PRINCIPLES AND PRACTICE 
OF 
CROWN AND BRIDGEWORK 
HART J. GOSLEE PRINCIPLES AND PRACTICE 
OF 
CROWN AND BRIDGEWORK 
A treatise upon the modern methods of restoring natural 
teeth, and of replacing missing teeth by means of 
artificial crown and bridgework. 
PY 
HART J. GOSLEE, B.S., D.D.S., F.A.C.D. 
ILLUSTRATED* 
FIFTH EDITION . 
BROOKLYN, NEW YORK 
DENTAL ITEMS OF INTEREST PUBLISHING CO. 
LONDON 
CLAUDIUS ASH, SONS & CO., LTD. 
1923 COPYRIGHT, 1903 
COPYRIGHT, 1907 
COPYRIGHT, I9IO 
COPYRIGHT, 1913 
COPYRIGHT, I923 
BY HART J. GOSLEE FOREWORD 
The wonderful advancements made in all branches of dentistry, and 
the splendid improvements made in the specialty of crown and bridgework, 
in particular, during the past few years, have seemed to demand an entirely 
new book to replace the few previous editions, and to justify the effort 
connected therewith. 
This work is offered to the teachers, practitioners and students of 
dentistry without apologies, but with the belief that it may be useful as a 
modern and practical text and reference book. 
The work was a work of love, and was inspired by the continued en- 
couragement of many friends and associates. To all of them assurances 
of deeply-felt gratitude, and of profound affection are expressed. 
Chicago, October Twenty-Third, 
Nineteen Twenty Three. 
Hart J. Goslee. CONTENTS 
CHAPTER PAGE 
I History 1 
PRINCIPLES AND TECHNICS OF CROWN WORK. 
II Indications for Artificial Crowns 12 
III Requirements of Artificial Crowns 16 
IV Metallurgy 29 
V Impressions and Casts 42 
VI Investment and Investment Compounds .... 49 
VII Soldering 54 
VIII Casting 67 
IX Preparation of Teetii and Roots 78 
X Gold Telescope Crowns 117 
XI Gold Telescope Crowns with Porcelain Facings . . 158 
XII Dowel Crowns 167 
XIII Porcelain Crowns 199 
PRINCIPLES AND TECHNICS OF FIXED 
BRIDGEWORK. 
XIV Bridgework 243 
XV Fixed Bridgework 253 
XVI Porcelain Bridgework 351 
PRINCIPLES AND TECHNICS OF REMOVABLE 
BRIDGEWORK. 
XVII Removable Bridgework 366 
PRINCIPLES AND TECHNICS OF CLASP 
DENTURE CONSTRUCTION. 
XVIII Clasp Dentures 410 
VII VIII 
CONTENTS 
FINAL CONSIDERATIONS. 
CHAPTER PAGE 
XIX Insertion of Gold Fillings in Porcelain Teeth and 
Facings 435 
XX Removing and Repairing 440 
XXI Finishing and Polishing 450 
XXII Mounting 456 PRINCIPLES AND PRACTICE 
OF CROWN AND BRIDGEWORK 
CHAPTER I. 
HISTORY. 
History records that the crowns of natural teeth were restored and 
missing teeth were replaced before the Christian era. Specimens of 
bands, of crowns, and of dental bridgework made by the Etruscans have 
been found and are preserved in the National Museum of Italy, in Naples, 
and in the Lombros collection at Athens. 
Writing in the fifth century b.c., Herodotus and Hippocrates refer 
to dental operations. Aristotle, also, wrote on the subject about 350 b.c. ; 
Horace, 65 to 8 b.c.; Ovid, 43 b.c. to 17 or 18 a.d., and Martial, who 
lived in Rome, and whose writings cover the period from 43 b.c. to 104 
a.d., was a satirist, as well as a poet, and in one of his poems runs this 
couplet: 
“False teeth and hair flaunts Laelia shamelessly, 
But not false eyes, for these she cannot buy.” 
From these writings it is evident that artificial teeth were made and 
used in Rome at that time. Other Latin and Greek poets, including 
Cicero, refer to them, and in the tenth century a.d., Abulcasis describes 
the operation through which artificial crowns were attached to adjacent 
natural teeth. 
These historical facts would indicate that the ancients of the classic 
period were proud of their teeth, and that efiforts toward restoration and 
replacement were made. 
It is the general belief that the Romans acquired their knowledge of 
dental restorations from the Etruscans, and the Etruscans and Greeks, in 
turn, from the Egyptians. 
I his belief is based on the fact that specimens of dental work have 
been found in the jaws of mummies buried probably 500 or 600 years 
before the Christian era. 
1 2 
CROWN AND BRIDGEWORK 
Artificial teeth made of ivory, bone, wood, or stone and attached to 
the natural teeth by means of cord, or gold, or silver bands, or ligatures, 
were the progenitors of modern artificial crowns. And natural teeth, 
bound together with gold bands, pioneered the way to modern bridge- 
work. 
Fig. i. 
Fig. 2. 
In so far as is known, no authentic specimens of fillings of equal 
antiquity have been discovered. Gold fillings believed to have been found 
in the teeth of Egyptian mummies, upon investigation, proved to be 
merely superficial applications of gold made for ornamental purposes. 
The Etruscan craftsmen, particularly, were familiar with a variety 
of the requirements of bridgework, and it is recorded that the Romans 
constructed both fixed and removable appliances. Among the relics 
found at Tanagra, which date from probably 600 b.c., and which are now 
preserved in the Lombros Collection at Athens, is one which points 
clearly to an effort to stabilize loose teeth by means of an assemblage of 
bands made of soft gold (Fig. 1), and another which shows an effort 
toward the replacement of missing teeth (Fig. 2). HISTORY 
3 
Whether dentistry became a lost art in the middle ages is not known. 
Dental literature at the beginning of the eighteenth century records the 
application of “pivot” teeth to roots, but the beginning of the resurrection 
of ancient methods was not marked until the early part of the nineteenth 
century, and the first evidences of the revival doubtless came from the 
French. 
Advent of Porcelain, 
In the remote ages human teeth, the teeth of cattle and sheep, hippo- 
potamus tusks, elephant and other ivories and bone were used for crown 
and bridgework restorations, but in 1728 Fauchard, a French dentist, 
proposed the use of porcelain. The actual manufacture of “mineral” 
teeth, however, did not begin until some time between 1774 and 1776 
Fig. 3. 
Fig. 4. 
when Duchateau, a French chemist, assisted by Dubois, a dentist of 
Paris, introduced porcelain teeth. 
The practical introduction of artificial restorations for the natural 
crowns of teeth lost through accident, or caries, and the ultimate devel- 
opment of the specialty of crowu and bridgework are products of the 
last half of the nineteenth century. This development is due to the pro- 
gressive efforts of American dentists, and to the application of the 
principles of American dentistry. 
Crown and bridgework has grown into an important specialty hand in 
hand with the growth of the profession as a scientific vocation, and even 
though no standardization of methods has been possible, the evolution of 
this specialty provides material for an interesting chapter in the history 
of dental art. 
New fields for higher esthetic conceptions have been opened through 
this specialty, and the general advancement of the profession has been 
promoted, for, at one time, it seemed that dentistry must be divided into 
two separate branches—operative and prosthetic. It was believed for a 
time that the average practitioner, who could or would become pro- 
ficient in both branches, would be the exception rather than the rule. 4 
CROWN AND BRIDGEWORK 
However, crown and bridgework, dividing the work of mind and hand, 
chair and laboratory, equally, reunited the two branches. 
Much of the advancement which the profession has made since then 
must, therefore, be placed to the credit of this specialty, and no field in 
art or mechanics offers greater opportunity for the display of artistic 
attainments and skilful craftsmanship. And the possession and de- 
velopment of these talents draws a fine line of distinction between the 
artisan and the true artist. 
Primitive Applications of Artificial Crowns. 
From available records, the first application of “pivot” teeth is described 
by Fauchard, 1728, in which description a crown, fastened to a root with 
a “pivot,” is mentioned. If a natural tooth was not available, the artificial 
Fig. 5. 
crown was carved out of bone or ivory, and was mounted upon the root 
with a roughened pivot of silver or gold- (Fig. 3.) The interior of the 
root was first filled with lead, into the center of which a hole for the recep- 
tion of the pivot was drilled, the other end of the pivot having been 
cemented into a hole in the crown previously. 
In 1816 de Chemant makes many references to the use of “mineral” 
paste and a brief description of a “single tooth with pivot” is given. The 
description is accompanied by a crude illustration which indicates it was 
intended to be attached to a root. (Fig. 4.) 
Other designs of “mineral” teeth are recorded in subsequent French 
literature, but it was not until about 1840 that much effort was made 
toward, or much thought given to, the problem of restoring lost crowns 
of teeth. It is evident that the prevailing and common practice then was 
to extract them and insert dentures, or, in some instances, to grind them 
down even with the gingival tissues and retain them for the purpose of 
preventing absorption. 
About this same time more progressive and esthetic ideas were con- 
ceived, and the English tube-teeth, designed and used previously for metal 
dentures, were introduced and adapted to the restoration of the natural HISTORY 
5 
crowns of teeth. (Fig. 5.) Originally they were ground to fit the support- 
ing root and mounted with pivots of hickory wood. 
This practice was a revelation, and marked the advent of modern 
crown work. The wooden pivot, however, was impracticable, because the 
expansion often caused a fractured root, while the presence of moisture, 
which was necessary to expansion, invited caries. 
Dodge Crown. 
Modifications of this method became necessary, and followed promptly. 
In 1844 a porcelain crown and a method of attaching it to the supporting 
root were patented by Dr. J. S. Dodge. This patent involved a wooden 
tube mounted in the root, and a porcelain crown having a pivot of gold 
or silver. The pivot engaged closely into the cylinder of wood by which 
Fig. 6. 
means the crown was attached, and removal made possible. As a means 
of permitting subsequent treatment, which frequently became necessary 
because of failure to obtain asepsis primarily, removal and replacement 
were demanded. 
In 1849 a crown was patented by Dr. F. H. Clark. This patent was 
simply for an improvement upon the Dodge crown, and involved the in- 
sertion of a metal tube in the root, instead of one made of wood. The 
crown was then anchored to the root by means of a “screw-pivot” having 
a large head and perforated through the center to allow “accumulated 
gases” to escape. 
Foster Crown. 
In 1855 a crown known as the Foster crown was patented. This crown 
had a base, almost flat, with a perforation in the body of the porcelain. 
The perforation was so shaped as to form a seat for the accommodation 
of the enlarged head of a screw-pivot by which means it was anchored to 
the root. (Fig. 6.) 
Mack Crown. 
In the preceding types the dowel was attached first to the crown, and 
then to the root- In 1872, however, a deviation was made, and a patent 6 
CROWN AND BRIDGEWORK 
was issued to Dr. C. H. Mack, covering an artificial crown in which the 
dowel was attached firmly to the root before the crown was mounted. 
The crown was made with a countersunk cavity in the body of the porce- 
lain, and was attached by filling this cavity with a plastic substance. 
(Fig- 7-) 
The Gold Telescope Crown. 
The possibility of restoring the crowns of posterior teeth by means 
of all gold crowns was probably conceived and suggested first by Dr. 
W. N. Morrison, but that type of artificial crown restoration which is now 
known as the gold telescope crown was patented in 1873 by Dr. J. B. 
Beers. 
Fig. 8. 
Fig. 7. 
The difficulty incident to adapting dowel crowns to posterior teeth 
led to the invention and application of the gold telescope crown. The 
application of a hollow telescoping restoration permitted the conservation 
of tooth structure, and made possible a useful and serviceable reproduction 
of the natural tooth crown. For the first time, the line of junction between 
crown and root was carried under or within the free gingival margin. 
The success of this type of crown for the posterior teeth has resulted 
in the invention of many systems and methods of construction, all of 
which, while varying in detail, accomplish practically the same end. 
Gates-Bonwill Crown. 
As a result of the successful application of the Foster and Mack 
crowns, an improvement appeared later and became known as the Gates- 
Bonwill crown. A patent was issued to Dr. W. H. Gates in 1875, and 
one to Dr. W. G. A. Bonwill in 1881, covering practically the same ideas. 
This crown was made of porcelain and was constructed with a concave, 
instead of a flat base, and with a triangular perforation through the body 
of the porcelain. (Fig. 8.) The formation of the perforation afforded HISTORY 
7 
a secure means of attachment to the supporting root. A metal dowel was 
threaded and screwed into the canal first, and the crown was then attached 
with amalgam. 
Howland-Perry Crown. 
Shortly afterward the Howland crown, subsequently modified by Dr. 
S. G. Perry, and designated as the Howland-Perry crown, was suggested, 
and manufactured. This crown was similar to the preceding types, but, 
like the Mack crown, differed in that the accommodation for the dowel 
was confined to a cavity in the body of the porcelain, instead of passing 
entirely through it. (Fig. 9.) The preservation of the continuity of the 
Fig. 9. 
Fig. io. 
exposed surfaces of the porcelain, thereby encapsulating the end of the 
dowel and the mounting medium, offered opportunities for greater per- 
manency and superior esthetics. 
“Richmond” Crown. 
In 1880 a type of artificial crown, which became known subsequently 
as the “Richmond” crown, was patented by Dr. C. M. Richmond. This 
type of crown consisted of a metal coping adapted to the end of the root, 
and a facing, similar to the ordinary flat-back facing, which was attached 
to the coping by soldering. 
This type of construction involved the first practical application of a 
peripheral band to the roots of anterior teeth. As originally designed, it 
consisted of a band, to which was soldered a floor, thus forming a coping. 
A facing of special design was attached to the coping by means of a 
threaded dowel which, passing through the coping, was screwed into a 
tube mounted previously in the root canal. (Fig. 10.) 
The original principle of the “Richmond” crown, however, was soon 
abandoned, but the modifications and improvements resulting from this 
suggestion are the basis of the accepted practice of to-day. 8 
CROWN AND BRIDGEWORK 
Buttner Crown. 
The practicability of using a peripheral band in the construction of 
dowel crowns for anterior teeth was questioned by many, and led to the 
introduction of the Buttner crown, invented by Dr. H. W. Buttner. The 
advantages of a peripheral band were recognized and also its possible 
irritating influences, and this led to an effort to obtain the former and 
avoid the latter. These features were accomplished by trephining the 
periphery of the basal end of the root, thus forming a shoulder for the 
Fig. 12. 
Fig. 11. 
accommodation of the band, and this idea, probably, was the progenitor 
of modern jacket and shoulder crown restorations. (Fig. 11.) 
How Crown 
Variations followed rapidly. In 1883 Dr. W. S. How devised a crown 
which became known as the How crown. This type of crown consisted 
of a thin facing having four pins, and a lingual surface formed to accom- 
modate a “screw-post” which was anchored to the facing by bending the 
pins. (Fig. 12.) The facing was backed, and the contour was built up 
with solder. 
Weston Crown. 
Another crown of similar type was invented by Dr. Henry Weston in 
1883. In the original design the dowel was formed in such manner as to 
engage the pins, as illustrated in Fig. 13. 
This method of attachment was modified subsequently, and the dowel 
was fixed securely to the root first and the crown was then held in con- HISTORY 
9 
tact with the root and attached by packing amalgam through the opening 
on the lingual surface. (Fig. 14.) 
It will be observed that up to this time crown and dowel consisted of 
two separate parts. A deviation from this principle followed, and the 
dowel became an integral part of the crown by being baked into the body 
of the porcelain. 
Fig. 13. 
Fig. 14. 
Fig. 15A. 
Fig. 15B. 
Logan Crown. 
The Logan crown was invented and patented by Dr. M. L. Logan in 
1885. This type of crown was made in porcelain with a platinum dowel 
as an integral part. More closely approaching the esthetic requirements 
than any of its predecessors, its use became popular for a time. 
Brown Crown. 
Shortly afterward Dr. E. Parmley Brown introduced a similar type 
of porcelain crown. This crown had the base convex instead of concave, 
with a view to affording the greatest degree of strength at the line of 
junction between crown and dowel, and between crown and root. (Fig. 
15 A.) 
The adaptation of the crown to the root was made by using a bur which 
produced a concavity to accommodate the convexity of the base of the 
crown. Because the increased strength of the crown was gained at the 
expense of the root, however, it was soon abandoned. 10 
CROWN AND BRIDGEWORK 
Webb Crown. 
The advantages to be obtained from a close adaptation of the artificial 
crown to its supporting root, and the difficulty incident to grinding one 
surface to fit another, stimulated a desire for better adaptation, and a 
metal coping was suggested by Dr. M. H. Webb. 
The coping was constructed by burnishing or swaging a metal base 
to fit the end of the root. The base was then perforated to admit the 
insertion of a dowel into the root canal. The dowel was then soldered 
to the base, and the facing attached subsequently. (Fig. 15 B.) The pos- 
sibilities of accurate adaptation, and its advantages, are now generally 
recognized, and this type of construction is still in common use. 
Porcelain Jacket Crowns. 
Throughout the evolution of artificial crown work, a desire for methods 
which might more closely simulate nature, and which might avoid the 
conspicuous display of gold, has been evidenced. This desire inspired a 
keener appreciation of the legend “true art is to conceal art,” and created 
a recognition of the full possibilities of porcelain work. 
Dentures of platinum and porcelain had been constructed successfully 
for many years; hence, it was believed that porcelain crowns and bridge- 
work might be constructed successfully also. The porcelain jacket crown 
followed. 
The first suggestions along these lines were made by Dr. C. H. Land. 
The primitive application met with varying degrees of success and failure, 
but this was due more to overenthusiasm and faulty technic than to any 
shortcomings in the porcelain itself, and this type of crown is now recog- 
nized as the most ideal method of procedure. 
Bridgework. 
The first presentation of modern methods of supplying missing teeth 
by means of bridgework was made by F. Maury in 1828, in a French work 
entitled “A Treatise on Dental Art.” This was translated into English by 
J. B. Savier in 1843. 
Among several illustrations in this book are two wherein remaining 
teeth, or roots, afford means of attachment for artificial teeth, without any 
apparent effort to stabilize the fixture by contact with the mucosa. 
In 1856 Dr. W. A. Dwindle suggested that which has been termed the 
“progenitor of modern bridgework.” This embraced a description of a HISTORY 
11 
method of adapting a coping to the end of a root, and attaching an arti- 
ficial tooth to it. The description was supplemented with the statement 
that “the plate may be carried across the intervening space unoccupied by 
roots, and an unbroken row of teeth mounted upon it.” 
This idea, broadcasted through the profession, brought about a renais- 
sance of methods of greater or less antiquity, and marked the beginning 
of an era of development which has resulted in the various bridgework 
technics of to-day. 
Fig. 16. 
In 1871 Dr. B. J. Bing contributed to this development by devising 
an artificial tooth made of porcelain, with a platinum bar projecting from 
each lateral side. The ends of the platinum bar were to be anchored in 
fillings in adjacent natural teeth. This became known as the “Bing 
bridge.” (Fig. 16.) 
While applicable to the replacement of a single tooth only, its intro- 
duction marked the advent of the modern application of fixed bridgework. 
In 1873 Dr. W. G. A. Bonwill devised a type of removable bridgework 
in which a metal tube, previously threaded on its inner surface, was 
mounted in the root canal and used as a means of affording attachment 
for a removable crown. The crown was adapted to the root and held in 
position by a threaded dowel which passed through a perforation in its 
base, and engaged the tube. The attachment was also capable of carrying 
an adjacent tooth. 
Modern dental bridgework, however, had its beginning with the advent 
of the gold telescope, and the band and dowel type of crown restorations, 
and its advent, therefore, dates back to the period between 1878 and 
1883, when the usefulness of these types of crown restorations was first 
recognized. Since then the development of methods has been rapid. 
From the very beginning, however, it will be observed that there has 
been an ever-growing tendency toward the development of esthetics. This 
has resulted in the introduction of many varying methods, embracing a 
multitude of ingenious ideas. While most of them have been but modifica- 
tions of original principles, and many were abandoned soon after their 
introduction, all have aided in the development of modern crown and 
bridgework, and stand as “records that defy the tooth of time.” Principles and Technics of 
Crown Work. 
CHAPTER II. 
INDICATIONS FOR ARTIFICIAL CROWNS 
Since it is not within the province of human effort to improve upon 
normal conditions, no artificial crown restoration is, or can be, as good 
as the natural crown of a tooth. And, furthermore, the same state of 
health that exists in the investing and environmental tissues of the natural 
crown rarely ever presents about an artificial crown restoration, irrespec- 
tive of the degree of accuracy obtained in its adaptation to the supporting 
tooth or root. 
Therefore, an artificial crown restoration is indicated as a last resort 
only, and when no other reparative process, or no other method of attach- 
ment for bridgework seems to offer opportunities, or possibilities, for a 
favorable or permanent restoration. 
In the application of artificial crowns the health of the investing and 
environmental tissues may and will be conserved in proportion as the 
restoration does, or does not, offer any degree of mechanical irritation. 
Evidences of mechanical irritation are quite common, but may be 
diminished or increased by the accuracy of the adaptation of the artificial 
crown to its supporting tooth or root. The crowning of a tooth, therefore, 
may be considered a successful operation in proportion to the skill dis- 
played and the accuracy obtained. 
Success in whatever line of art or mechanics depends largely on one’s 
visualizing the completed work. If one has the power to visualize the 
possible result, before commencing the procedure, creative ideas, so essen- 
tial to success, are more readily inspired. 
The field of artificial crown and bridgework offers splendid opportuni- 
ties for the attainment of more than average skill, and for the display of 
the highest artistic talents. Skill and talent alone, however, do not always 
insure success. Accuracy, facility and deftness in instrumentation must 
12 INDICATIONS FOR ARTIFICIAL CROWNS 
13 
be acquired to a degree of efficiency that will inspire the confidence of the 
patient. Details must be observed keenly. 
Methods which are quickest are not always best. The operator must 
be governed by the most conscientious efforts in using judgment and dis- 
crimination regarding the particular method most applicable to the case 
in hand. Often, upon preliminary examinations, several methods seem 
applicable, but, upon closer study, usually one method in particular will 
meet all requirements best. 
With recognition and appreciation of these basic principles, artificial 
crown restorations'are indicated in three general classes of cases: 
First: In extensive loss of tooth structure from the ravages of caries, 
or from accidental causes. 
Second: In occasional cases of malformation, malposition and dis- 
coloration in which an artificial crown may offer the best means of insur- 
ing usefulness and permanency in the restoration of impaired function, 
and of affording relief from disfigurement. 
Third: As a means of obtaining anchorage for bridgework. 
Class i—Extensive Caries. Accidental Causes. 
Extensive Caries. The most typical indications for the application 
of an artificial crown are embraced by those instances where the natural 
tooth crown has suffered to such an extent from caries as to make restora- 
tion by filling, with any assurance of permanency, a negative or doubtful 
procedure. 
In all cases where it seems a question of judgment as to the advisa- 
bility of effecting the restoration by means of a filling, or by means of 
an artificial crown, unless for esthetic reasons, the preference should be 
given to filling, provided that any reasonable degree of success and per- 
manency may be insured. 
Frequently, the remaining walls of badly broken-down teeth or roots 
may be protected and usefulness restored by the insertion of a dowel 
into one or more of the canals, either as a separate or as an integral 
part of the filling. Such a procedure is often indicated, and often prefer- 
able because of the fact that restoration by means of an artificial crown 
may thus be deferred. Indeed, a crown may become a remote necessity, 
for a well-adapted and well-anchored filling is more conducive to the con- 
servation of the normal condition of the investing and environmental 
tissues than the most skilfully adapted artificial crown. 
Accidental Causes, The loss of a portion or of all of the natural 
tooth crown as the result of a fall, blow, or other accident, or from ab- 14 
CROWN AND BRIDGEWORK 
normal masticatory stress upon hard substances is by no means uncommon. 
Such cases usually call for immediate relief, and often the restoration may 
be most efficiently made by means of an artificial crown. 
Class 2—Malformation. Malposition. Discoloration 
Malformation. In conditions of faulty enamel formation, such as 
conical or “peg-shaped” laterals (Fig. 17), or pitted structure such as is 
Fig. i 7. 
Fig. 18. 
found often in the incisors and first permanent molars (Hutchinson’s 
teeth) (Fig. 18), the application of a full artificial crown restoration may 
be indicated as the best means of affording permanent relief from 
disfigurement. 
Malposition. In cases of simple irregularity, or malposition, of one 
or more of the anterior teeth (Fig. 19), where the age of the patient, the 
presence of caries, or other environmental conditions may not seem to 
warrant correction by the usual orthodontic procedures, the desired re- INDICATIONS FOR ARTIFICIAL CROWNS 
15 
suit may often be obtained by sacrificing the natural crown and substituting 
an artificial one, as the simplest means of correcting the malposition. 
Discoloration. A conspicuous and embarrassing disfigurement is 
often caused by the presence of badly discolored anterior teeth. When the 
discoloration refuses persistently to yield to repeated efforts at chemical 
bleaching, an artificial crown may often be indicated as the best and 
simplest means of effectively and permanently relieving the disfigurement. 
Class 3—Anchorage for Bridgework. 
Irrespective of the emphasis placed upon the desirability of conserving 
the natural crowns of teeth, and the possible irritating influence of an 
artificial crown, the application of artificial crowns may sometimes be indi- 
Fig. 19. 
cated as the best means of obtaining adequate and permanent anchorage 
for bridgework. 
The use of artificial crowns for this purpose, however, should not be 
regarded as being indicated generally, nor should an artificial crown be 
regarded as the only means through which adequate or permanent attach- 
ment to the supporting teeth, or roots, may be obtained. But some type 
of artificial crown restoration often may seem to insure a greater measure 
of strength and permanency in the replacement of missing teeth than it 
would be possible to obtain with any other procedure. 
The indications for the utilization of artificial crowns as attachments 
for bridgework, therefore, should be determined only after careful con- 
sideration, and must be based on good judgment. The mutilation of the 
natural crown of a good, sound tooth for any purpose is always a serious 
and questionable procedure and should never be viewed with indifference. CHAPTER III. 
REQUIREMENTS OF ARTIFICIAL CROWNS. 
No superstructure can be more enduring than its foundation; hence 
no artificial crown of any type can be better or endure longer than its 
supporting tooth or root. 
Hence, when it has been determined that an artificial crown is indicated, 
every preliminary and basic requirement which may have to do with obtain- 
ing and insuring a conservation or restoration of the normal health and 
function of the tooth, or root, together with its investing and environ- 
mental tissues, must be observed. This applies whether the artificial crown 
indicated is to restore the tooth, or root, as a single unit, or for the pur- 
pose of obtaining anchorage for bridgework. 
It is essential that the operator should have a broad, general knowledge, 
first, of the preliminary requirements which are fundamentally necessary 
to placing such teeth, or roots, as are to support artificial crowns in the 
most favorable condition possible; and, second, of the basic requirements 
upon which comfort, usefulness and permanency will depend. 
Preliminary Requirements.—These preliminary requirements may 
be considered in three general classes: 
First: Physiological requirements; 
Second : Pathological requirements; 
Third: Therapeutic requirements. 
A recognition and appreciation of the importance of each of these re- 
spective preliminary features necessarily must precede a consideration of 
all others. 
Physiological Requirements 
Histology teaches that the dental pulp is the developmental organ of 
the tooth and that its physiological function practically terminates with 
complete root-end development. Apparently, therefore, the pulp itself is 
not necessarily essential to the vitality, health, stability and longevity of 
the tooth, thereafter, provided that it may be thoroughly and aseptically 
16 REQUIREMENTS OF ARTIFICIAL CROWNS 
17 
removed, and that the root canals may be filled completely under the same 
conditions, all of which is now recognized as an absolute requirement for 
health. 
It is recognized further that whenever pulp destruction, pulp removal 
and root canal filling may be accomplished under these conditions, the 
tooth so treated will receive sufficient nourishment through the peridental 
tissues to sustain it, and that it may continue its normal functional ac- 
tivity more or less indefinitely, although deprived of its main source of 
nourishment. 
Notwithstanding this generally recognized fact, and irrespective of the 
highly developed degree of skill attained in the technic and in the applica- 
tion of modern aseptic means in thus removing pulps and in treating and 
filling root canals, it remains a further indisputable fact that a pulpless 
tooth is not so good as one having a vital pulp. Invariably, too, there is 
some element of doubt or uncertainty regarding the thoroughness with 
which root canals may be completely filled in all cases, and particularly 
in malformed roots and multirooted teeth. 
Pulp Devitalization.—The devitalization of pulps for any reason 
whatever is a procedure demanding the most serious consideration, and 
is a practice now justifiable or excusable, only when the requirements 
permit of absolutely no other course. 
With modern technic, and with radiographs as a first aid, there should 
be but little uncertainty regarding the successful filling of the root canals 
of all normally formed single rooted teeth. But the uncertainty attached 
to cases embracing abnormally formed roots, or multirooted teeth, together 
with the possibilities of reinfection, or of subsequent infection demands 
most serious consideration of the case in hand. 
For many years no special consideration was given to the importance 
of pulp conservation, nor to the possible serious troubles which might be 
the sequelae of pulp destruction and imperfect root canal filling. The 
devitalization of pulps, in a large percentage of all teeth to be restored by 
means of some form of artificial crown, was quite generally taught and 
practiced. 
During this period, devitalization was regarded as a preventive measure, 
and, therefore, as a safer procedure. Several more or less tenable reasons 
justifying these teachings and practices were given. 
First among these it was claimed that the removal of the pulp is 
necessary in a large percentage of cases as a means of making it possible 
to shape the remaining tooth crown properly, in order to adjust a well 
adapted and correctly fitted artificial crown. 18 
CROWN AND BRIDGEWORK 
In all cases where a crown having a full telescoping band is to be made, 
and particularly in bicuspids and molars where the remaining natural 
crown is of typically normal form, the actual mechanical requirements of 
root preparation are so exacting as to make devitalization a necessity in 
many cases. Hence, whenever this type of artificial crown must be used, 
a close adaptation to the supporting root must obtain. And, if the de- 
struction of the pulp is necessary as a means of making this adaptation 
possible, it is then, to this extent, still a justifiable procedure. 
If a suitable restoration might obtain from the use of some other type 
of artificial crown, however, or from any method other than a crown— 
one through which the vitality of the pulp may be conserved—such pro- 
cedure is the better practice. 
Secondly, it was a prevailing belief that the application of a full arti- 
ficial crown with a telescoping band, demanded so much grinding and 
shaping of the remaining natural crown that disastrous results would 
follow. Also it was believed that as a result of shock to and over- 
stimulation of the pulp, calcification in the form of secondary dentin, pulp 
nodules, and other pathological disturbances would follow in many cases. 
Such possibilities, of course, would be lessened by the age of the pa- 
tient, and would become a negative consideration, perhaps, in advanced 
age, on account of the gradual atrophic degeneration of the pulp, but such 
a result might be produced in the teeth of young and middle-aged patients. 
In any and all cases, however, such a possibility is to be eliminated to 
a large extent by careful technic, or by conduction anesthesia or nerve- 
blocking. Hence, it is not now to be regarded as a tenable reason for pulp 
devitalization. 
And, third, it was claimed that the complete inclosure of a tooth having 
a vital pulp would establish an abnormal condition. It was claimed that 
the gold crown and the intervening cement would so isolate the tooth from 
the external influences of moisture and temperature that it would be ex- 
cluded from its quota of nerve and blood supply, and that the ultimate 
result would be a complete loss of pulp vitality in many cases. 
Such a result, of course, is possible, but the complete abandonment of 
the full telescoping gold crown is, nevertheless, doubtful. Clinical experi- 
ence proves that it has afforded many years of useful service in tooth 
restorations; but even the possibility of such a result, remote or rare as 
it may be, suggests that the complete enclosure of a tooth having a vital 
pulp undoubtedly establishes a condition which is not altogether ideal. 
Therefore whenever and wherever possible, it should be avoided and 
preference given to some other form or type of restoration which will not 
endanger the vital pulp even thus remotely. REQUIREMENTS OF ARTIFICIAL CROWNS 
19 
Pulp Conservation.—From every viewpoint, therefore, it must be 
recognized that every effort should be made to conserve the vitality of the 
pulp in all teeth and in all cases. Its destruction, though necessary at 
times, must be regarded always as a radical procedure and as indicated 
only when demanded by the requirements of the case. And this is 
especially important in the teeth of young patients where complete root- 
end development has not yet obtained. 
The final word with regard to pulp conservation, then, may be encom- 
passed in the statement that the vitality of all pulps should be conserved 
whenever and wherever possible, and that pulp destruction is excusable 
only when absolutely demanded. 
Pathological Requirements. 
The treatment of pulpless and infected teeth is recognized as a most 
important pathological consideration in its relation to the requirements 
fundamental to the conservation and restoration of the natural teeth by 
any reparative procedure. 
It is especially important at the present time, because some modern 
writers and teachers of prominence claim that a pulpless tooth is a “dead” 
tooth. Irrespective of whether the tooth has ever been infected, or whether 
any attachment of the periapical tissues remain, they claim its retention 
is a certain and positive menace to health. 
These teachings, almost revolutionary in portent, have gained many 
followers who regard the intrinsic value of the natural teeth in negative 
terms. 
The more conservative writers, teachers and practitioners, however, do 
not accept such views without question. They maintain that the natural 
teeth have a valuation in their relation to the human economy far exceed- 
ing any form of artificial substitute; and that consequently, every efifort 
should be made to conserve and restore them to health and usefulness, 
rather than to condemn them at once as being hopeless. 
Focal Infection. There is no doubt that root ends of pulpless teeth 
may become foci of infection. There is no doubt that they may be and 
often are causative or contributing factors, responsible for distant lesions 
and general systemic disturbances; but to accept the theory that root-end 
infection as diagnosed mainly by the radiolucent areas shown in the radio- 
graph is invariably the cause for all hidden or remote physical disturbances, 
not otherwise so easily traced, and to condemn all pulpless teeth because 
of this, is to be regarded as a radical and irrational practice. It is also 
a reflection upon the progress made in the study of the chemistry and 20 
CROWN AND BRIDGEWORK 
pathology of pulp decomposition and in the scientific teachings of modern 
dental therapeutics. 
Scientific investigation is now being made with a view to obtaining 
definite knowledge regarding the root ends of teeth and whether specific 
germs may be traced to them. And, so long as conflicting opinions regard- 
ing the relationship between focal infection, associated with teeth, and 
metastatic diseases in general are held, it is but rational to conclude that a 
conscientious, well directed effort to save pulpless teeth is safe and sane 
practice. 
The more conservative thinkers along these lines are firm in the belief 
that the ultimate findings in the solution of the problem will be that a 
properly treated and well filled pulpless tooth is a safe unit in an otherwise 
healthy group or environment, and that it may be expected reasonably 
to perform its normal function indefinitely, much better than any form 
of artificial substitute. 
They are also firm in the belief that if all pulpless teeth are a menace 
to health, if they must be removed irrespective of the cause of lost vitality 
or the age of the patient; and irrespective of whether their root canals 
are properly filled, or whether they have ever been infected; and, if the 
value and efficiency of the natural teeth, as compared with artificial sub- 
stitutes of any form, are to be of no consideration whatever, then, until 
such time as preventive dentistry shall have made restorative and repara- 
tive procedures unnecessary, an era of edentulous jaws, inefficient masti- 
cation, faulty metabolism, impaired nutrition, artificial dentures and 
premature old age is inevitable. 
It is readily admitted, however, that a knowledge of pathology, a cor- 
rect diagnosis, and a favorable prognosis are essential to success in deter- 
mining the borderline of safety in the retention of pulpless teeth. Also, 
that any effort to eradicate hopelessly incurable pathological conditions is 
misdirected energy in all cases, and a dangerous practice in many cases. 
Every assurance that health, comfort, usefulness and permanency will 
result, is demanded in all cases and under all conditions in placing an 
artificial crown upon a pulpless tooth or root, because a moral responsibility 
for the health of the patient is thus and thereby assumed. 
A knowledge of the possible dangers of root-end infections and their 
sequelae, and a realization of this responsibility, are absolutely essential 
and demand—• 
First: That all pathological conditions must be cleared up, and— 
Second: That the canals of all pulpless teeth must be filled thoroughly 
and their apices sealed hermetically before any permanent prosthetic pro- 
cedure follows. REQUIREMENTS OF ARTIFICIAL CROWNS 
21 
Well directed, conscientious effort along these lines, combined with 
the application of modern technic, and supplemented by the use of radio- 
graphs as an aid both to diagnosis and to proving the results obtained, 
will insure success. Much will depend, however, upon a correct interpre- 
tation of the radiograph. While radiographs are not infallible, they are an 
invaluable guide and an indispensable aid in all cases. 
In the light of present knowledge, the prevailing conservative teach- 
ings and opinions indicate that every reasonable effort should be made to 
conserve pulpless teeth, unless absolutely irrefutable evidence of incurable 
lesions, which may be traced directly to the teeth, be present. If all of 
the pathological requirements in the composite should not be recognized 
fully, appreciated keenly and observed carefully, then the removal of pulp- 
less teeth undoubtedly would be the safer and more rational procedure. 
As a result of these teachings and of our present knowledge, undoubt- 
edly a more wholesome respect for pulp vitality and its conserva- 
tion, and a higher regard for the necessity of a more careful and positive 
diagnosis in the treatment and management of pulpless teeth will prevail. 
A summary of the entire subject relative to the retention of pulpless 
teeth may be stated thus: 
All existing pathological conditions or lesions must be cleared up, 
primarily, and a state of health of the teeth and of their investing and 
environmental tissues must obtain under any and all circumstances. 
This applies also to teeth having vital pulps, and to the eradication of 
pyorrheal pockets, and other expressions of periodontoclasia. 
Therapeutic Requirements. 
The therapeutic requirements to be observed in the preparation of teeth 
and roots which are to support artificial crowns are the same as apply 
to any form of restoration. 
When the requirements of the case demand pulp devitalization, and a 
correct diagnosis and a favorable prognosis have been made, the necessary 
therapeutic treatment, which will aid in obtaining and maintaining asepsis 
and health, should be the first consideration. This is obvious in all efforts 
directed toward the conservation of pulpless teeth. 
In the treatment and filling of the root canals, the isolation of the tooth 
or root by means of the application of the rubber dam is always indis- 
pensable. Its use affords immunity from moisture, facilitates the procedure 
and reduces the possibilities of reinfection. 
In cases where the remaining natural crown may be badly broken down, 
or entirely gone, the careful fitting of a temporary band will facilitate the 22 
CROWN AND BRIDGEWORK 
application of the rubber dam to a great extent. The band, if properly 
fitted, may be worn throughout the treatment and filling of the canals. 
When the rubber dam is properly adjusted, the use of the usual thera- 
peutic agencies indicated by the requirements should follow. And they 
should be continued until thorough and certain asepsis obtains. The root 
canals then should be filled to their entire length, irrespective of the type 
of artificial crown to be used. The root filling should be temporarily pro- 
tected with cement until it has become well solidified. 
As the life and usefulness of all pulpless teeth depend upon the thor- 
oughness with which the root canals are filled, the importance of this 
procedure cannot be overestimated. In every case it is vital that every 
modern means of insuring success, including radiographic aid and proof, 
should be observed. 
Basic Requirements. 
The basic requirements fundamental to the restoration of teeth or 
roots by means of an artificial crown of any type and upon which comfort, 
usefulness and permanency will depend, may be classified as follows: 
First:—Anatomical requirements. 
Second :—Mechanical requirements. 
Third :—Esthetic requirements. 
Anatomical Requirements. 
The first group, designated as anatomical requirements, embraces a 
consideration, first, of the importance of a reproduction of natural tooth 
crown formation, and of a restoration of approximal contact and marginal 
angles; and, second, a knowledge and study of occlusion, and functional 
activity. 
Reproduction of Natural Tooth Form. Since it is quite impossible 
to hope to improve upon Nature, under normal conditions, a close repro- 
duction of natural tooth form must be recognized as essential to the suc- 
cessful construction and application of artificial crowns of any type. 
To this end, a study and thorough knowledge of the typical form of 
the crowns of natural teeth must be recognized as absolutely necessary. 
These may be obtained from casts of the normal denture, or from a study 
of dental anatomy, or both. 
Approximal Contact. A restoration of the normal approximating 
relationship between artificial crowns and the natural crowns of adjacent 
teeth in any place in the denture is an absolute necessity. It is a considera- REQUIREMENTS OF ARTIFICIAL CROWNS 
23 
tion of the greatest importance. Only by a good, close contact may the 
interproximal tissues be protected from the influences of irritation, and 
normal health maintained. These tissues are so susceptible and so respon- 
sive to irritation that the normal condition must be preserved. And, fur- 
ther, without a restoration of good, close contact, proper mastication with 
any degree of comfort is impossible. 
Marginal Angles. Only through a close and careful reproduction 
of the marginal angles in the restoration of the bicuspids and molars is it 
possible to secure the greatest efficiency in mastication and the maximum 
of protection to the investing tissues. Both conditions are absolutely es- 
sential to the maintenance of health and comfort. 
This requirement is quite as important as that of approximal contact, 
and. likewise, must be observed. 
Articulation and Occlusion. 
Heretofore the terms “articulation” and “occlusion” have been used 
more or less synonymously, and their definitions have been vague, elastic 
and misleading. Since these terms do not mean the same thing, and for 
the purpose of aiding in the establishment of a correct terminology, the 
following definitions, suggested by the Committee on Nomenclature of the 
American Dental Association, are accepted by the author, and will be used 
throughout this work. 
Occlusion: The contact of the teeth of both jaws, when closed, or 
during those excursive movements of the mandible which are essential 
to the function of mastication. 
Centric occlusion: The contact of the teeth when the jaws are closed 
in the position of rest. 
Eccentric occlusion: The contact of the teeth in the excursive move- 
ments of the mandible. 
Functional occlusion: Such contact of the teeth of both jaws as will 
provide the highest efficiency during all the excursive movements of the 
mandible which are essential to the function of mastication, without pro- 
ducing trauma. 
Traumatic occlusion: Such contact of the teeth of both jaws as 
would induce trauma during centric or eccentric occlusion, because of the 
malposition of the teeth, or the disarrangement of the occlusal planes. 
Malocclusion: Such malposition of the teeth as will interfere with 
the highest efficiency during the excursive movements of the mandible 24 
CROWN AND BRIDGEWORK 
which are essential to the function of mastication. This would not neces- 
sarily indicate lack of occlusal contact when the jaws are closed, nor would 
it always indicate traumatic occlusion. 
Articulation: The arrangement of artificial teeth to conform to the 
requirements of the edentulous space, or spaces, which they are to occupy, 
and to adequately serve the purposes of the natural organs which they are 
intended to replace. 
Articulation refers to the actual placing of artificial teeth, one by one, 
into required position; but articulation is not to be used to describe the 
occlusal relations of artificial teeth after they have been arranged. 
Functional Activity.-—Function is the keystone of occlusion, and 
only through the establishment and maintenance of functional occlusion 
is resistance sustained and disease prevented. 
A restoration of the normal functional activity of the supporting tooth 
or root, and the degree of usefulness, comfort and permanency of an ar- 
tificial crown, or any other form of restoration, depends largely upon an 
accommodation for functional occlusion during the process of articulating 
the artificial substitute. 
Therefore, it is necessary to make every effort to reproduce the natural 
tooth form for the accommodation of all movements and excursions of the 
mandible. 
The result of faulty or imperfect occlusion usually manifests itself in 
the form of more or less acute peridental inflammation, followed by loose- 
ness and soreness, finally resulting in traumatic occlusion, which is often 
the direct cause of broken crowns or of fractured roots. 
Thus it will be observed that the requirements of articulation and oc- 
clusion are highly important, and a part of crown and bridge construction 
that cannot be overlooked nor underestimated. 
Indeed, it is such an important feature that carbon paper, or other 
similar material, such as lampblack mixed with vaseline, is essential in the 
final adjustment of all forms of restoration to meet these requirements. 
Mechanical Requirements. 
The second group of requirements may be designated as mechanical, 
and embrace a consideration of the essential features of first, adaptation; 
second, stress; and third, strength; all of which bear materially upon 
comfort, usefulness and permanency. 
Adaptation. The susceptibility of the investing and environmental 
tissues to any degree of mechanical irritation, and the more or less irrep- REQUIREMENTS OF ARTIFICIAL CROWNS 
25 
arable injury to health and function resulting therefrom, together with 
an appreciation of the further requirements of prevention, demands that 
an artificial crown be adapted to its supporting root accurately. The 
adaptation must be sufficiently accurate to preclude the possibilities of un- 
due irritation. 
This means that an artificial crown must “fit’ both the basal end and 
the periphery of the root, irrespective of the type of crown used. In pro- 
portion as a conservation of the continuity of the root obtains, the degree 
of accuracy of adaptation between crown and root increases, Hence, in 
proportion as the “fit” is good or bad, the possibilities of irritation will be 
decreased or increased. 
In other words, the better the crown fits the root, the less the irritation 
produced and the greater the health of these tissues; and the greater the 
health of these tissues, the greater the comfort and permanency obtained. 
Thus, it is evident that an artificial crown should be so constructed and 
so adapted as to offer but little, if any, irritation to these tissues. And, 
to this end, every precaution which will aid in avoiding irritation must 
ever be observed. 
Furthermore, the possibilities of subsequent disintegration of the 
supporting tooth or root from caries, or of a dissolution of the mounting 
medium, either of which, sooner or later, would result in failure, are 
minimized, or eliminated entirely, by the degree of accuracy obtained in 
the adaptation. Thus, it will be observed, that permanency, as well as 
health, depends upon accuracy. 
Stress. All of the teeth in the normal denture are subjected to the 
influences of stress in different directions in accordance with their func- 
tional requirements and activities. 
The findings and teachings of Prof. G. V. Black have proved that the 
natural teeth in a normal denture are capable of sustaining stress to a 
degree that varies from one hundred and twenty-five pounds to two hun- 
dred and fifty pounds; and, in some instances, even more, according to 
the size of the teeth, the density of their supporting structures and the 
power of the masticatory muscles. 
Any type of artificial crown, therefore, must be constructed and at- 
tached to its supporting tooth, or root, with a view to withstanding this 
degree of stress and to accommodate any and all variations. 
The line of the greatest natural resistance to stress is in a vertical 
direction. Hence, every precaution should be made to prevent undue or 
unnatural stress in any other direction. It must be remembered that no 
tooth, or root, will accommodate abnormal stress to any great degree in 26 
CROWN AND BRIDGEWORK 
any direction, other than vertical, and remain permanently comfortable and 
healthy. 
The stress assumed by the six anterior maxillary and mandibular teeth 
tends to force them outward and forward. These natural tendencies are 
to be accommodated only by a close observation of the requirements of 
root preparation, restoration of approximal contact and the method of at- 
tachment of the artificial crown to the root. 
The functional activities of the bicuspids cause them to receive stress 
in both vertical and lateral directions. Provision must be made for this 
stress in the same manner, though perhaps not to the same degree, as in- 
dicated in the restoration of the anterior teeth. 
The molars are least susceptible to displacement, due to the fact that 
lateral stress is limited in proportion to the degree of the normal accuracy 
of occlusion. And, as the greatest stress is in the direct, or vertical line, 
the essential requirement is a good, firm seating, supplemented by accu- 
rate occlusion. 
Strength. Inherent strength, both in the crown itself and in the 
method by which it is attached to its supporting tooth, or root, is an 
essential to the mechanical requirements of crown construction. 
It must obtain to a degree that will be adequate to the demands of 
stress in any type of crown and in all cases. Even the always desirable 
feature of esthetics must be sacrificed sometimes to insure a degree of 
strength necessary to meet these requirements. 
Attachment to Supporting Tooth. 
Two distinct mechanical principles are the basis of adequate strength in 
attaching artificial crowns to their supporting teeth, or roots. Both of 
these principles are indicated, first, by the type of crown to be constructed; 
and, second, by the exposed surface of natural tooth crown remaining, 
and to which the attachment may be made. These involve the telescoping 
principle and the dowel principle. 
Telescoping Attachment. Wherever enough of the natural tooth 
crown remains to insure adequate strength in the attachment of an arti- 
ficial crown by telescoping over it, the principle may be used successfully. 
If the artificial crown may telescope over the remaining natural crown 
equal to one-half of the length of the artificial crown, from the gingival 
line to the incisal edge or occlusal surface, adequate strength in the at- REQUIREMENTS OF ARTIFICIAL CROWNS 
27 
tachment will obtain. And this strength increases in proportion to the 
increase in length of the telescoping surface contact. 
Dowel Attachment. Wherever all of the remaining natural crown 
must be, or is already, sacrificed to the gingival line, leaving no oppor- 
tunity for the adoption of the telescoping principle, a secure mechanical 
fixation of the crown to the root may be obtained by extending a dowel of 
proper size into the root canal to a distance equal to the length of the arti- 
ficial crown. 
The dowel may or may not be an integral part of the artificial crown, 
but must be attached securely thereto. 
This method of attachment is indicated in the restoration of all an- 
terior teeth or roots, with any type of crown, other than the porcelain 
jacket, in order that the esthetic requirements may be observed. 
Esthetic Requirements. 
Esthetic requirements embrace a field of effort giving the greatest 
possible scope to individuality and artistic talent on the part of the operator. 
An artificial crown should preserve the gingival outline and the sym- 
metrical alinement of the adjacent teeth to comply with the highest at- 
tainments in esthetics. It should be of the same length as the adjacent 
teeth, and, if of porcelain, it should match them closely in color. And, if 
within the range of vision, it should correspond in general form and in 
type and characteristics with the corresponding tooth in the opposite side 
of the natural denture. 
Where porcelain is used, no metal should be visible unless displayed 
to conform more closely with the adjacent teeth or corresponding tooth. 
Where the remaining natural teeth are filled freely with the gold, small 
fillings in the artificial crown produce a greater degree of harmony with 
its neighbors thus making detection more improbable. Legitimate decep- 
tion is true evidence of art and Nature’s great law of harmony should be 
observed always. 
Epitome. 
The requirements of an artificial crown, in the composite, epitomized, 
are as follows: 
First: The primary requirement is essentially the health of the sup- 
porting tooth, or root, and of its investing and environmental tissues. 
Second: It must restore the typical anatomical form of the natural 
crown, including marginal angles, cusps, sulci, embrasures, and approxi- 
mal contact with adjacent teeth. 28 
CROWN AND BRIDGEWORK 
Third: It must meet all the requirements of articulation and occlusion, 
and normal function. 
Fourth: A restoration of the peripheral continuity must obtain be- 
tween crown and supporting tooth, or root, with a degree of accuracy that 
will offer no mechanical irritation to the investing and environmental tis- 
sues, and which will insure protection from subsequent caries and perma- 
nency in the attachment. 
Fifth: A degree of inherent strength adequate to the requirements of 
stress must obtain, both in the crown and in the method of its attachment 
to the supporting tooth, or root. 
Sixth: It must preserve the symmetrical alinement of the adjacent 
teeth. And, if within range of vision, must match them closely in size, 
type and color, and simulate the corresponding tooth on the opposite side 
of the natural denture. And, all unnecessary display of gold or other 
metal should be avoided. CHAPTER IV. 
METALLURGY. 
The metals and their alloys, their characteristics, physical properties 
and methods of manipulation, play an important part in the field of oral 
restorations. 
A study and a broad and comprehensive knowledge of dental metal- 
lurgy, therefore, is a requirement scarcely second in importance to those 
which have been designated as basic. 
It is not now necessary for the dental prosthetist to be an expert metal- 
lurgist, or to refine, alloy, or otherwise prepare his metals for any and all 
special purposes. This is done better and much more scientifically by 
reliable dental gold manufacturers. But the acquirement and development 
of skill in manipulation of these special products is necessary at all times. 
The Metals. 
Organic chemistry teaches there are fifty-two known metallic elements. 
Of these it is necessary to consider only those which are used more or 
less generally in dentistry. They are included in the following table: 
Metal 
Symbol 
0 F. 
0 C. 
Gold 
Au 
2016 
1102 
Platinum 
Pt 
3632 
2000 
Iridium 
Ir 
More refractory than Pt. 
Copper 
Cu 
1996 
1091 
Silver 
Ag 
1873 
1023 
Zinc 
Zn 
773 
412 
Lead 
Pb 
617 
326 
Tin 
Sn 
442 
228 
Bismuth 
Bi 
507 
264 
Cadmium 
Cd 
442 
228 
Antimony 
Sb 
842 
45° 
Alumini 
A1 
1292 
700 
Iron 
Fe 
3000 
1600 
Nickel 
Ni 
3000 
1600 
Fusing Point 30 
CROWN AND BRIDGEWORK 
Expert gold and platinum smiths are not metallurgists, necessarily, 
but they are master manipulators of metals. And the requirements of 
modern crown and bridgework now demand that the dentist, too, should 
be in possession of similar knowledge and craftsmanship. 
Classification of Metals. 
Metallurgy divides the metals into two groups, known as noble and 
base, and so classified because of their affinity for and property of com- 
bining with oxygen. 
Noble Metals. The noble metals have less affinity for oxygen, do 
not combine with it so readily, and are more easily separated from its com- 
binations when subjected to heat. 
The noble metals are gold, silver, platinum, and iridium. 
Base Metals. The base metals have a much greater affinity for 
oxygen, combine with it more readily, and are separated from it with 
more difficulty because their compounds are not decomposed by heat. 
The base metals are copper, tin, zinc, lead, bismuth, cadmium, antimony, 
aluminum, iron and nickel. 
Physical Properties. All metals of both groups possess distinctive 
physical properties. To facilitate the skilful manipulation of those used 
more or less extensively, it is essential that one should understand thor- 
oughly the nature of the metals and their alloys. 
Chemical Action. All metals are more or less susceptible to the 
chemical action of the oral secretions. Gold and platinum are the least 
affected. Platinum withstands any action, and permanently retains its 
color and luster much better than gold. This is due probably to the fact 
that platinum is used mainly in its pure state of fineness, while gold, 
nearly always, is alloyed with one or more of the base metals. 
The action upon gold in its pure state of fineness is practically the same 
as upon platinum. But, under the influence of the oral secretions at body 
temperature, it oxidizes and tarnishes in direct ratio to the proportion of 
base metals used in alloying or in reducing to the state of fineness. 
It is recognized that the soft tissues seem to tolerate, or take more 
kindly to platinum than to gold—probably due to this superficial oxida- 
tion, characteristic of the latter. 
Odor and Taste. All metals have a distinct odor and taste, but 
noticeable only to an infinitesimal extent. 
Copper and zinc carry the most distinct metallic odor and taste. This METALLURGY 
31 
is of no special importance, however, for they are used merely for the 
purpose of alloying and the odor and taste are apparent only when they 
are subjected to a temperature higher than body temperature. 
Color. Each metal possesses a characteristic color. These colors 
vary from the grayish-white of platinum and silver, to the muddy blue of 
lead, and from the rich, bright yellow of gold, to the dark, red-dirt color 
of copper. The color of all metals is modified by alloying. 
Gold and platinum possess color and luster that, in contrast, is more 
pleasing to the eye, more in harmony with the environment and least 
susceptible to change by the chemical action of the oral secretions. 
Malleability. Malleability is an inherent property of a metal which 
admits of its being hammered, or rolled, into thin sheets without destroy- 
ing the continuity of its surface, and permits of its easy manipulation and 
adaptation. 
Ductility. Ductility is the property which admits of metals being 
drawn out into lengths of a small diameter, such as wire. 
Tenacity. Tenacity is the property of molecular resistance to tension 
upon which depends the strength of the metal. 
In studying the accompanying table, it will be noted that gold, while 
ranking first of the five principal metals most commonly used, in malle- 
ability and ductility, ranks last in tenacity. This, of course, refers to pure 
gold, the tensile strength of which is greatly increased by alloying with 
copper, silver or platinum. 
Malleability 
Ductility 
Tenacity 
Rank i: Gold 
Gold 
Iron 
Rank 2: Silver 
Silver 
Copper 
Rank 3: Copper 
Platinum 
Platinum 
Rank 4: Platinum 
Iron 
Silver 
Rank 5: Iron 
Copper 
Gold 
Density. The density of metals depends upon the intimacy of the 
relationship or contact between the molecules. This property is influ- 
enced by expansion and contraction, by the temperature to which it is 
raised and the rapidity with which it is cooled. 
Fusibility. All metals are capable of being reduced to a fluid state 
under the influence of heat. But like the color, the fusing point, or 
degree of fusibility, differs greatly and is modified by alloying. 
The high fusibility of platinum of any thickness greatly facilitates 
some classes of work; and the control, at will, of the fusing point of gold, 32 
CROWN AND BRIDGEWORK 
by alloying, makes the assemblage of innumerable parts and the art of 
soldering comparatively easy and simple. 
Physical Processes. 
The physical processes which concern the dentist mostly in the manipu- 
lation of the metals are those of soldering, welding, annealing, temper- 
ing, and alloying. A knowledge of each is important. 
Soldering. Soldering is the process of uniting surfaces of metal 
by superficial alloying. 
Welding. Welding is the process of uniting surfaces of metal by 
molecular attraction under heat and pressure. 
Annealing. Annealing is the process of softening, or increasing 
malleability. As all metals expand under the influence of heat, they, in 
turn, become softened because of the separation of the molecules produced 
by expansion. 
To accomplish this, they should be heated slowly to a cherry red and 
allowed to cool gradually. Plunging gold or platinum into water, how- 
ever, does not interfere with the process of annealing; and to plunge 
either into alcohol seems even to increase their softness. 
Tempering. Tempering is the process of hardening. In gold, plati- 
num, silver, copper, etc., it obtains as the result of manipulation, due to 
molecular condensation. Iron containing carbon (steel) is tempered by 
sudden thermal changes from various degrees of heat. This produces 
hardness in proportion to the quantity of carbon present, and the man- 
ner and method of cooling. 
Alloying. Alloys are a combination of two or more metals and alloy- 
ing is, of course, the process of combining metals. A study and knowledge 
of this art is important, because so few metals now used are in their 
pure state. 
Most metals enter freely into combination with others and the alloy 
produced frequently possesses characteristics entirely different from those 
of any one of the component metals. They always fuse lower than the 
highest fusing and often lower than the most easily fusible. In compound- 
ing them, the least fusible usually should be melted first in a clean crucible, 
and the others added in relation to and in accordance with their fusibility, 
after first carefully weighing out the proper proportions. 
Alloys of gold, copper and silver can be melted and incorporated al- METALLURGY 
33 
most simultaneously, with comparative ease. Those containing platinum 
or zinc are more difficult. Platinum, usually, is added by feeding it into 
the molten mass in thin foil form. Zinc is best incorporated in the shape 
of brass, or some other alloy of known formula, because of the rapidity 
with which it volatilizes. 
When zinc is to be added in the pure state, the proper quantity should 
be weighed, broken into small pieces and each piece coated with a film 
of paraffin, or wax, then thrust quickly into the molten mass. 
In compounding alloys it is necessary to be familiar with the table of 
troy weight commonly used by metallurgists. 
Troy Weight 
24 grains (gr.) 1 pennyweight (dwt.) 
20 pennyweight (dwt.) = 1 ounce (oz.) 
12 ounces (oz.) 1 pound (lb.) 
Scale. 
lb. oz. dwt. gr. 
1 12 240 5760 
1 20 480 
1 24 
Field of Usefulness of Metals. 
Each of the metals and its alloys has a distinct field of usefulness as 
applied to crown and bridgework. This field will be considered in the order 
of each metal’s relative value for various purposes. 
Gold. The color, malleability, compatibility and slight susceptibility 
to the chemical action of the oral secretions and other qualities possessed 
by gold, make it easily the nearest approach to the ideal for universal use. 
While the highest artistic and esthetic efforts should be directed toward 
avoiding its conspicuous display as much as possible, its sphere of useful- 
ness is unlimited. 
Owing to its softness, the uses of pure gold necessarily are limited in 
prosthetic procedures. Its use is confined usually to backings for porce- 
lain facings, crown copings, etc., where a close adaptation is desired and 
where it is afterward to be reinforced. 
Karat. Twenty-four is the quotient used to denominate purity. In 
alloying gold the term karat is applied to the degree of fineness. Thus, 
karat designates the proportion of pure gold to the ratio of 24 parts. 
Hence, 24 K. is virgin gold, while 18 K. is composed of 18 parts of gold 
and 6 parts of other metal or metals used for alloying. 34 
CROWN AND BRIDGEWORK 
Platinum. Platinum has rapidly acquired an extensive field of use- 
fulness in dental art, and, because of its many admirable physical prop- 
erties, is second only to gold. 
The properties of malleability and practical infusibility are valuable 
and have made possible the successful application of porcelain work in all 
of its various phases. It withstands the chemical action of the secretions 
so much better than gold that it ranks first in compatibility with the tis- 
sues. It is used extensively also in alloying gold, to which it imparts spe- 
cial properties. 
Iridium. The physical properties of iridium resemble platinum, but 
are more refractory. Its use is confined to alloying with platinum, the 
combination forming a tougher, harder alloy, such as is indicated in cast- 
ting alloys, and in other instances where more than ordinary strength is 
required. 
Alloys. 
Alloys of Gold. For the purpose of reducing the fineness and in- 
creasing the strength of pure gold, copper and silver mainly are used 
for alloying, usually in the proportion of two parts of copper to one of 
silver. Copper imparts hardness and strength and silver imparts pliability 
and a preservation of the original color, which copper alone would change. 
For crown and bridgework, where strength and good color should be 
combined and are prerequisites, the gold most generally used to the best 
advantage is of about 22 K. fineness. This is necessary to resist or to se- 
cure immunity from the chemical action of the secretions, retain its color 
and luster and withstand the stress. Tt is used in rolled plate and of a 
thickness varying from 28 to 30 United States Standard Gage. 
The following are three basic formulae used for this purpose: 
No. 1—22 K. 
Pure gold 22 dwt. 
Pure copper 1 dwt. 
Pure silver 18 gr. 
Platinum 6 gr- 
No. 2—21.6 K. 
Pure gold 90 parts 
Pure copper 5 parts 
Pure silver 5 parts 
No. 3—21.6 K. 
Coin gold 50 parts 
Pure gold 45 parts 
Pure silver 5 parts METALLURGY 
35 
Coin Gold. The United States coinage—gold go, copper io—for 
many years was the means of furnishing an alloy which was used ex- 
tensively. It is, perhaps, not used so extensively now because of its hard- 
ness and because of the characteristic reddish color, which is not particu- 
larly pleasing to the eye when contrasted with the bright yellow of a pure 
gold filling. 
Coin gold may be used to good advantage, however, in combination 
with pure gold and silver in proper proportions, because of the definite 
knowledge of the proportion of copper it contains. 
Gold and Platinum Alloy. Platinum in various proportions is used 
as an alloy for gold wherever additional strength, elasticity and increased 
fusing point are desired. Platinum, varying from 5 per cent to 10 per cent, 
gives these properties to the alloy. 
Platinized Gold. “Platinized” gold is a form of drawn plate made 
by fusing pure gold over one surface of platinum, which, when passed 
through rollers, presents a smooth, unbroken surface of each metal. It is 
used where extreme thinness and greater infusibility is desirable. It is 
used also for backings for porcelain facings, because of the advantage 
of controlling or preserving the color by placing next to the porcelain that 
surface which will cause the least change, or produce the most desirable 
change. 
Casting Alloys. The advent and successful application of the casting 
process has almost completely revolutionized the character and require- 
ments of alloys of gold and platinum used for other purposes. It has 
created a demand for various kinds of alloys, each one possessing special 
physical properties and characteristics which make it applicable to the re- 
quirements for some particular line of casting. 
The casting of a metal, or of an alloy, brings about an entirely differ- 
ent arrangement of the molecules and results in a product entirely differ- 
ent from that which the same metal, or alloy, would produce if rolled or 
drawn. This molecular rearrangement undoubtedly diminishes the in- 
herent strength and increases the brittleness of all alloys. 
Gold and platinum are, of course, the basic metals in compounding 
alloys for casting. Pure gold is easily and successfully cast, but the cast- 
ing is too soft for any purpose other than inlays. And, even in inlays, 
22 K. gold is generally used. It is regarded as better than pure gold be- 
cause of its better retention of form and contact under the influence of 
stress. 
For the same reason 22 K. gold is recommended generally for castings 36 
CROWN AND BRIDGEWORK 
for crown and bridgework in all cases where accuracy of adaptation is 
paramount to strength. 
But where strength and elasticity in the casting are required, it be- 
comes necessary to combine various other metals which will impart the 
desired physical characteristics, and also add to the flowing and spreading 
properties of the alloy. 
An alloy which flows and spreads smoothly is cast more easily. It 
also casts to the finer details of the mold with greater accuracy than a 
heavy, sluggish alloy. Therefore any combination of metals designed to 
meet special requirements must be worked out along scientific lines. 
The scientific compounding of alloys discloses the fact that those com- 
binations which will produce and insure desirable requirements in fusi- 
bility and in efficiency after casting, and, particularly, those of the harder 
and more springy class, will show necessarily a greater tendency to oxidize 
in melting and casting. This tendency to oxidize, however, is not es- 
pecially injurious to the casting and may be taken care of by the use of 
the proper reducing flux. If this precaution is not always taken, the 
alloy is likely to be sluggish and to cast indifferently. 
Scientific tests prove conclusively that it is not possible to compound 
an alloy suitable to the requirements and possessing desirable physical 
characteristics which will not oxidize under the influence of heat. 
The overheating of any alloy in melting should always be avoided, 
however, as this increases oxidation. The higher the heat, the greater the 
tendency of an alloy to absorb oxids; hence, when brought to a white heat, 
and when boiling and sputtering, an alloy is too hot to be cast. 
An ideal condition for casting any alloy is immediately after the surface 
coating breaks and a mirrorlike surface presents. And, as long as the 
alloy is molten, the cooler it is at the time of casting, the smoother will be 
the casting. But the greater the disturbance caused by excessive heat, the 
less accurate and smooth will be the casting. And, furthermore, great care 
must be taken always in melting an alloy to guard against carbonizing 
and oxidizing influences. 
Solders. 
Platinum Solders. The advent of procelain work and the use of 
high-fusing porcelain compounds on a base of platinum demand a solder 
more infusible than pure gold. This is necessary in order that joints so 
made will not be affected by the high degree of heat necessary to fuse or 
vitrify these compounds. 
If there is absolute contact of the parts to be united by soldering, pure METALLURGY 
37 
gold may be used successfully in small pieces; because if thoroughly fused 
it will be absorbed by and alloy with the platinum. But, in extensive work, 
platinum solder is an advantage because its use overcomes the possibility 
of any change in the relation of the parts which may be caused by the 
shrinkage of the porcelain compound in fusing. 
Platinum solders are now prepared for this purpose, varying in the 
percentage of platinum in combination with gold. Less than 20 per cent 
platinum is of no advantage, and more than 25 per cent is unnecessary. 
Gold Solders. Gold solders are alloys of gold so compounded as 
to fuse slightly lower than plate gold of the same fineness, or karat. They 
should be composed of the same metals in order to preserve a close re- 
semblance in color, and differ only in the incorporation of a base metal 
which will reduce the fusing point and impart flowing properties. Thus 
20 K. solder, for instance, should fuse readily on 20 K. plate; otherwise it 
would not be a “solder.” 
Zinc and bismuth are used mostly for reducing the fusibility and im- 
parting the requisite flowing properties. They should not be used in 
greater proportion than il/2 to 2 parts in 24, however. If incorporated 
in greater quantity, the alloy would be rendered brittle, the strength di- 
minished, and the susceptibility to chemical influences increased when 
exposed to the action of the oral secretions. 
Solder of a lower karat than is absolutely necessary should never be 
used. The lower the karat the greater the susceptibility to chemical action 
and to oxidation. Consequently, the joint and all exposed surfaces are 
rendered more or less conspicuous. It is always desirable to use solder 
of as high karat as possible to begin with so that subsequent solderings 
may be made with a degree of fineness of solder which will aid in pre- 
cluding this tendency. 
All grades of solders invariably run lower than the karat stamp upon 
them; hence 16 K. and 14 K. solders have but a very limited field of use- 
fulness. 
The following formulae will give an idea of the average composition of 
the various grades of dental solders: 
22 K. Solder 
Pure gold 22 parts 
Brass 2 parts 
Coin Solder 
Coin gold 5 dwt. 
Brass i dwt. 38 
CROWN AND BRIDGEWORK 
20 K. Solder 
Pure gold 20 parts 
Dorrance’s alloy 4 parts 
18 K. Solder 
Pure gold 18 parts 
Pure silver 3 parts 
Pure copper 1 part 
Brass 2 parts 
Compounding Solders. 
Because of the ease with which the various karats of plate golds and 
solders may be procured now by the dentist, it is scarcely necessary to be 
familiar with the methods used in ascertaining and computing the fine- 
ness of gold. But, as it may be desirable sometimes to compound solders, 
it is well to know the method of reducing scrap gold of known fineness to 
the various karats of solder desired. 
The following simple rule will enable any one to reduce a given quality 
of scrap gold of given fineness to any desired karat of solder: 
Rule for Compounding Solders.—Multiply the weight of gold by 
the karat and divide by the desired karat. The difference between the 
answer, after dividing, and the original quantity of gold, is the proportion 
of alloy necessary to be added. 
Example. Reduce 4 dwt., 3 gr., 22 K. gold to 18 K. solder. 
4 dwt., 3 gr. (original quantity) equals 99 gr. 
99 X 22 (original karat) equals 2178. 
2178 divided by 18 (desired karat) equals 121. 
121 minus 99 (difference between result and original quantity) equals 
22. 
Answer: 22 gr. of alloy should be added. 
Base Metal Alloys. 
For the purpose of compounding solders, the alloy used should contain 
copper and zinc, or silver and zinc. Such alloys may be obtained in con- 
venient form in known formula, such as brass, Dorrance’s alloy, or silver 
solder. 
Brass. Brass is composed of copper and zinc in proportions suitable 
for the purposes for which it is to be used. The proportions usually vary METALLURGY 
39 
from equal parts of each, to 70 of copper and 30 of zinc. Owing to the 
close resemblance to gold in physical properties, characteristics, and even 
color, brass is much used in various lines. When used as an alloy for gold 
in compounding solders, its definite formula should be ascertained. 
Dorrance’s Alloy. An alloy, known as Dorrance’s alloy, is used ex- 
tensively in reducing gold to solders. It is a combination of the three 
principal metals used, in good proportions, with copper in the preponder- 
ance. Following is the formula: 
Copper 6 parts 
Silver 2 parts 
Zinc 4 parts 
Silver Solder. Silver solder is an alloy of copper, silver and zinc, 
with silver predominating. It is used extensively in making gold solders. 
Being a “hard’' solder it is used also in various lines of work embracing 
brass and German silver. A common formula follows: 
Silver 6 parts * 
Copper 3 parts 
Zinc 1 part 
German Silver. The alloy known commercially as German silver is 
used to some extent for temporary purposes and temporary work of all 
kinds. It is composed of copper and zinc, in combination with nickel, 
which metal increases the fusing point and makes a harder, tougher alloy. 
The following formula is much used: 
Copper 50 parts 
Zinc 30 parts 
Nickel 20 parts 
Fusible Alloys. Fusible alloys are those alloys in which the lower 
fusing base metals, such as lead, tin, bismuth, antimony and cadmium 
are combined in varying proportions. They are useful for making dies 
and counter-dies for swaging, and for the purpose of obtaining casts 
directly from plaster, or compound impressions, or from “mouldine” 
compounds. 
The extreme fusibility of these alloys depends, to a large extent, upon 
the proportion of bismuth incorporated, and varies accordingly. 
The following are formulae of some of the various well-known alloys, 
with their approximate fusing points: 40 
CROWN AND BRIDGEWORK 
No. 1 
Bismuth 5 
Lead 4 
Tin 2 
Cadmium 1 
Fusing point 140° F. 
No. 2 
Bismuth 8 
Lead 8 
Fusing Point 1740 F. 
Tin 3 
No. 3 
Bismuth 8 
Lead 5 
Tin 3 
Fusing point 200° F. 
No. 4 
Bismuth 8 
Tin 5 
Lead 3 
Fusing point 2200 F. 
The lower fusing of these alloys may be cast or poured directly into 
plaster, gutta percha or compound impressions. But they never should 
be overheated in melting, and should be cast just before they begin to 
congeal. 
Soft Solder. The use of soft solder in dentistry may be indicated 
sometimes in temporary work. Ordinary tinner’s solder is composed of 
equal parts* of tin and lead. Any of the fusible alloys will answer the 
purpose equally as well. Zinc chlorid is the “flux” for soft solder. 
Flux for Base Metals. Base metals and their fluxes are used in 
the dental laboratory only in exceptional operations. 
The best flux for lead is resin. Paraffin, wax, Burgundy pitch, gum 
dammar, gum copal, etc., have the same properties as rosin, but are no 
better and are much more expensive. 
Tallow and palm oil are used for tin, and sal ammoniac is the flux used 
for zinc. 
Refining Scrap Gold. 
The scrap gold that accumulates in the laboratory often becomes so 
contaminated with base metals that it could not be melted and used 
over again without first having been subjected to some simple process of 
refining. 
The Roasting Method. When the scrap is composed mostly of a 
known degree of fineness, the refining may be accomplished quite easily 
without resorting to the chemical process, by what is known as the “roast- 
ing” method. 
This consists of placing the scrap in a clean crucible with plenty of 
borax. Heat then is applied until a perfect fusion is reached, when small 
pieces of potassium nitrate (saltpeter) should be added consecutively; or, METALLURGY 
41 
equal parts of borax and potassium nitrate may be mixed together pre- 
viously, and then added. 
This oxidizing agent furnishes sufficient oxygen to oxidize all base 
metals and the oxids are absorbed by the borax. If kept up long enough, 
the gold will be refined sufficiently to be used over again. 
Recovering and Refining Waste Gold. 
The average dentist, probably, does not have time, nor the facilities, 
for recovering the waste gold that daily finds lodgment in, or becomes at- 
tached to sweepings, rugs, carpets, disks, strips, etc., yet the method usu- 
ally employed in reclaiming and refining it may be of general interest. 
The Wet Method. The sweepings and such various articles as may 
contain gold are placed first in a suitable vessel. Then they are subjected 
to a degree of heat in a blast furnace which will reduce them to ashes 
and residue which, afterward, is powdered finely. 
The next step is to separate the gold from most of the ash, carbon, sand, 
etc., by the mechanical process of washing. During this process, because 
of the high specific gravity of the metallic masses, they seek the lowest' 
point, allowing the residue to remain on top. 
The gold may be extracted from the remaining mixture of heavy ma- 
terials by the following method: 
Treat with nitrohydrochloric acid (aqua regia); heat gently; agitate 
occasionally; and then allow the mixture to stand for a few hours. 
The solution now is evaporated until all free acid has been expelled, 
when it is allowed to cool and alcohol and potassium chlorid are added, pre- 
cipitating any platinum that may be present. 
The gold then may be precipitated from the filtered solution by adding 
ferrous sulphate, C. P.; or, by heating it with a solution of oxalic acid, 
when the precipitate, a fine, brown powder, should be washed with dis- 
tilled water, placed in a graphite crucible and fused thoroughly with po- 
tassium nitrate (saltpeter) or borax, or a combination of both, as previ- 
ously indicated. CHAPTER V. 
IMPRESSIONS AND CASTS. 
In the building of crown and bridgework much of the detail of 
adaptation may be executed directly upon the supporting teeth and roots 
in the mouth, but the actual details of construction must be done upon 
what may be termed a reproduction of the normal foundation. 
Hence, a means of obtaining this reproduction with certainty and ac- 
curacy, and of thus transferring the field of work from the patient to the 
laboratory, is necessary. 
This reproduction of the normal foundation is obtained, primarily, by 
means of a mold or of an impression. No reproduction is ever as accurate 
as the original, however, and no reproduction can be any more accurate 
than is the means by which it is obtained. 
A mold or an impression of the teeth, roots and associated parts, there- 
fore, and one as accurate as it is possible to obtain, is essential to an 
equally accurate reproduction, or cast. And an accurate cast is the equiva- 
lent of an accurate means of transfer from patient to laboratory- 
Too much emphasis, therefore, cannot be given to the importance of 
exercising every effort, first, to obtain a good, accurate impression, and, 
second, to obtain as a resultant a good, accurate cast. 
Cast or Model. 
The cast or “model” which is to become the foundation upon which all 
of the technical details of construction are to be completed must be not 
only an accurate reproduction, but also must possess strength and inde- 
structibility adequate to the requirements. 
The terms “cast” and “model” are generally, but wrongly, used more 
or less synonymously. Cast means that which is obtained by pouring or 
otherwise introducing a plastic substance into a mold and subsequently 
separating it therefrom; model means a pattern or an object to be copied. 
The impression, then, becomes the mold and is filled with a plastic sub- 
stance that subsequently crystallizes and is separated therefrom. The re- 
42 IMPRESSIONS AND CASTS 
43 
sultant is the cast. Being scientifically correct, therefore, the term cast 
is to be used exclusively. Its use should become general. 
Impressions. 
The impression is the intermediary between the original foundation 
and its replica, or reproduction. It is the means of transferring not only 
the foundation itself, but also various parts of the work in process of con- 
struction. 
Regardless of the talent or the skill displayed in building the super- 
structure, its adaptation can be no more accurate than the cast upon which 
it is built; nor can the cast be more accurate than the impression from 
which it is obtained. 
Thus, if accuracy is to obtain at all, it must begin with the impression. 
For this purpose two materials are used—plaster of paris and impression 
compound. 
Plaster of Paris. The requirements of accuracy demand the use of 
a material for impressions which will be applicable universally and depend- 
able always. Plaster of paris is absolutely the only substance which will 
subscribe to these demands. It will not draw nor pull in removing; it will 
fracture before it is distorted and it is this feature that insures accuracy. 
A good grade of “impression” plaster should “set,” or crystallize 
quickly. The rapidity of crystallization may be controlled by the use of 
potassium sulphate or sodium chlorid. 
Impression Tray.—A form of impression tray suitably adapted to 
the requirements of the case should be selected and care should be exer- 
cised ; first, to have the mix as thick as can be used without danger of 
setting too rapidly; second, to avoid any unnecessary surplus; third, to 
adjust it to place accurately in the mouth; and fourth, to hold it firmly 
in position until crystallization begins. 
As soon as a small surplus piece of the same mix may be broken to a 
clean fracture between the fingers, the impression should be gently, but 
firmly, loosened, but not removed. It should then be allowed to remain 
until well crystallized. To loosen it before it becomes thoroughly crystal- 
lized will cause it to fracture easily, where fracture is to be, thus facili- 
tating the subsequent detachment and removal. It also diminishes the 
strain placed upon the remaining natural teeth in its removal. 
If the tray used has been prepared previously in a manner which will 
insure the removal of the body of the impression with it—a precaution 44 
CROWN AND BRIDGEWORK 
always to be observed—it is of little consequence if the impression is frac- 
tured into any number of pieces. If all pieces are reclaimed they may be 
replaced in their proper relation and sustained in position with melted wax. 
Another method which will be found very effective in insuring an accu- 
rate impression, requires that the impression tray be kept bright and 
smooth, and it is well to advise the patient that the tray, when removed, 
will leave the plaster in the mouth. As soon as the plaster has thoroughly 
crystallized, the tray is removed, and the plaster scored in suitable places 
to permit the plaster which is towards the face to be broken off, usually 
in three pieces, after which the part against the palate usually is readily 
removed in one piece. But whatever number of pieces there may be, they 
are to be thoroughly washed under a running water faucet, to remove 
minute particles. The tray is also similarly washed, after which the pieces 
of plaster are assembled in the tray, rather loosely. When all are prop- 
erly placed, they can be forced into correct and very close relationship, the 
tray acting as a restraining matrix. 
Fig. 20. IMPRESSIONS AND CASTS 
45 
For single crowns and small bridges, simple crown and bridge impres- 
sion trays are used. These are made in several designs. One is adjustable 
and adapted to universal use. The others are adapted to unilateral appli- 
cation only, and are designated as right and left. By transposing, they 
are applicable to both upper and lower arches. (Fig- 20.) For larger 
cases the ordinary partial or compound impression trays are used. 
(Fig. 21.) 
Fig. 21. 
Where any of the parts of work under construction are to be removed 
with the impression, it should be noted carefully that they are in their 
proper positions and held securely. This precaution is very important. 
Assured that the impression is sufficiently accurate and satisfactory 
in all its details, it should be allowed to dry and then be varnished with 
some preparation that will insure and facilitate separation. 
Separating Fluids. Any good separating fluid which will insure 
separation, afford a line of demarkation between impression and cast, and 
impart a smooth surface to the cast, will answer the purpose. 
A coating, first, of shellac varnish and then of sandarac varnish prob- 
ably gives the best results. Collodion, colored with potassium perman- 
ganate, or an indelible lead pencil, also gives good results. Thin oils and 
soap are used also, but do not make a line of demarkation, nor insure a 
smooth surface to the cast, both of which are important considerations. 
Many commercial separating fluids are prepared and answer the purposes 
satisfactorily. 46 
CROWN AND BRIDGEWORK 
At this point every detail that will insure strength in the cast should 
be observed. A precaution which will insure a maximum of strength in 
the reproduction of the teeth, and particularly where teeth stand alone 
and are unsupported, may be observed by placing an ordinary pin, point 
downward, into the mold of such teeth in the impression. (Fig. 22.) Thus 
strengthened, it is seldom that teeth break off and greater accuracy results. 
Pouring the Cast. When the impression has been prepared, it should 
be dipped in water and poured. 
Fig. 22. 
A good grade of “cast” plaster should be used in making all casts that 
are not to be subjected to the heat of soldering. 
Where great indestructibility and the minimum change of form are de- 
manded, the magnesium oxid compounds and a compound known com- 
mercially as “metcom” are useful. 
But in all cases where soldering is to be done directly on the cast, the 
cast must be made of some high-grade investment compound. These 
compounds withstand heat far in excess of plaster, which is disintegrated 
at a temperature much lower than that required for soldering. 
Separating Cast from Impression. It has been suggested that the 
body of the impression usually should cling to and be removed with the 
impression tray. This is to be insured by notching or indenting the edges 
of the tray, or by attaching a rim of wax securely to the edges, or both. 
Because of this precaution, care must be exercised in separating; first, 
to remove the tray without endangering the cast; and, second, to trim the 
impression slowly and carefully to a point which discloses the line of de- 
markation made by the varnish. The remaining thin portions may then 
be removed cautiously without defacing the cast or breaking off the teeth. IMPRESSIONS AND CASTS 
47 
Self-separating Plaster. A self-separating plaster compound com- 
mercially known as “complaster” is also used for impressions, and is use- 
ful for many purposes. This compound is manipulated like ordinary 
plaster. In its use the impression is separated from the cast by placing it 
in tepid water and then increasing the temperature, gradually, until the 
boiling point is reached. It should then be boiled until the “complaster” 
impression is dissolved entirely. If liquid silex is used as a separating 
varnish a cast having smooth and definite surface outlines results. 
Impression Compounds. The use of impression compound, com- 
mercially called “modeling compound,” for impressions for crown and 
bridgework is not recommended. It is a material which provides an easy 
means at the expense of accuracy. 
Any material, like impression compound, which remains more or less 
plastic at body temperature, or which will pull or draw in removing, is 
entirely inadequate to the requirements of accuracy. Even the most diffi- 
cult or complex case would offer no excuse for its use. Indeed it is in such 
cases that a degree of accuracy far beyond the possibilities of compound, 
or of similar materials, is demanded. 
Taking the Bite. 
The procedure which has to do with obtaining and transferring the 
correct occluding relationship of the opposing teeth, and which, for the 
want of a better term, perhaps, is referred to as “taking the bite,” is second 
in importance only to the impression. 
It is a procedure always replete with uncertainty and one which de- 
mands close observation and painstaking care if accuracy is to be insured. 
Whenever any parts of the work under construction are to be trans- 
ferred to the cast by means of the impression, the “taking of the bite” 
must precede the taking of the impression. This becomes necessary be- 
cause the parts which are to be removed with the impression must be in 
place when the “bite” is taken in order that the “bite” may be adjusted 
correctly to the cast with the parts in place thereon. 
Pink base plate wax is the best material for the purpose. The “bite” 
should include all adjacent remaining natural teeth and should afford a 
good, deep imprint of the opposing teeth. Every precaution must be 
taken to insure a correct reproduction of the occlusal relationship of the 
opposing teeth. 
The requirements of accuracy also demand the exercise of care in the 48 
CROWN AND BRIDGEWORK 
adjustment of the wax “bite” to the cast, and in filling completely the im- 
prints of the opposing teeth in mounting the case upon the articulator. 
For this purpose a good, hard plaster should be used because a maxi- 
mum degree of indestructibility of the opposing teeth, when mounted upon 
the articulator, will facilitate and insure a more accurate occlusion. 
In instances where these requirements are specially exacting, greater 
accuracy will result from filling the imprints of the opposing teeth in the 
wax bite with any of the so-called “artificial stone” compounds. And 
even amalgam often may be used for this purpose to advantage. The time 
required for hardening or for crystallization will be compensated for 
through greater indestructibility and increased accuracy. 
Fig. 23. 
Articulators. 
No form of articulator now used will meet all of the requirements of 
articulation and occlusion satisfactorily. 
The requirements of accuracy in reproducing functional occlusion in 
crown and bridgework are to be obtained best from the use of some type 
of “anatomical” articulator in all cases. 
An approximate reproduction of lateral mandibular movements is al- 
most as essential in crown and bridgework as it is in denture construction. 
For single crowns and small bridges, however, a simple form of crown 
and bridge articulator (Fig. 23) may answer the purpose. CHAPTER VI. 
INVESTMENT AND INVESTMENT COMPOUNDS. 
In crown and bridgework the finished product, whether it be small or 
large, simple or complex, presents as a single unit, or as one or more in- 
terrelated single units. But, just as the mass is composed of atoms or 
molecules, and tissues are made up of cells, this finished product in the 
composite is made up of an assemblage of several or many basic units. 
In the technical details of construction, the assemblage of these basic 
units must be made with every possible degree of certainty and accuracy. 
And certainty and accuracy obtain only by observing some means of tem- 
porarily sustaining the desired relationship of these units until their per- 
manent assemblage may be effected. 
To sustain this relationship in a secure and dependable manner and 
otherwise to protect each and every single unit as the requirements may 
demand is the purpose of the investment. 
Purpose of Investment. The combined purposes of the investment, 
therefore, are, first, to sustain the correct relationship of all of the single 
units of which the piece is to be composed while they are being assembled 
permanently; and, second, to protect any and all parts which require, or 
demand, protection by the more or less equal distribution of heat during 
the process of assemblage. 
All metals and all minerals expand and contract under the influence of 
heat and cold. And in exact ratio to the control of this expansion and con- 
traction by the gradual and uniform distribution of heat, will the resulting 
molecular changes be harmful or harmless. 
The physical properties of the metals are so entirely different from the 
physical properties of the minerals that special care must be exercised 
whenever both are to be used in the same combination, and are to be sub- 
jected to the influence of excessive heat at the same time. 
Porcelain absorbs and gives off heat so slowly in comparison with gold 
that whenever porcelain teeth or facings are to be assembled in combina- 
tion with gold or platinum, which is frequently necessary, they must be 
protected against the possibilities of being heated too rapidly, cooled too 
49 50 
CROWN AND BRIDGEWORK 
rapidly, or too sudden expansion or too sudden contraction. The invest- 
ment affords this protection. 
Preliminary Requirements. Previous to their investment, the re- 
lationship of all units to be assembled must be securely sustained, first, 
with hard wax. When this has been done, the surfaces of all metal to 
which solder is to become attached, upon which it is to flow and with 
which it is to become alloyed, should be covered with wax. This precau- 
tion is necessary in order to keep these surfaces clean, uncovered and 
freely exposed in the investment, after the wax has been removed, either 
by burning out or with boiling water. 
A special “hard” wax, made hard by the incorporation of resin, is pre- 
pared for the purposes of crown and bridgework by the manufacturers 
of dental supplies and always should be used in this work. 
Requirements of Investment. Where the cast has been made of 
investment compound and it is desired to assemble the parts, under con- 
struction, without removing them from the cast, first submerge or dip 
the cast in water of normal temperature and then apply the investment 
compound. This should be mixed to a proper consistency and in sufficient 
proportions to sustain securely the relationship of all parts, and to insure 
their necessary protection during the application and under the influence 
of the required heat. 
As all reliable investment compounds necessarily are composed of re- 
fractory and more or less infusible ingredients, it follows that they are 
also poor conductors of heat. 
The completed investment, therefore, never should be larger in size 
than sufficient to insure adequate strength. The larger the investment, the 
more heat required in the assemblage of the parts. Hence, when the added 
quotient has become thoroughly crystallized, all unnecessary surplus above 
and beyond the actual requirements should be trimmed away as a means 
of economizing, both in length of time and degree of heat. 
Removing Parts from Cast. Whenever it is desirable to preserve 
the cast for further use, or whenever the cast may have been made of plas- 
ter, instead of investment compound, the parts to be assembled must be 
transferred to a separate investment. 
While not quite so reliable, this procedure may be accomplished safely, 
first, by detaching carefully all parts fixed in their positions on the cast in 
such manner as will admit of their accurate replacement. 
When thus detached and replaced, the desired relationship of all parts 
to be assembled should be sustained securely with hard wax. The whole 
then should be removed from the cast and invested separately. INVESTMENT AND INVESTMENT COMPOUNDS 
51 
The single units may be detached from the cast in an easy and accu- 
rate manner, and mutilation of the cast prevented, by painting the surfaces 
of the exposed parts in the impression, before pouring the cast, using 
melted wax applied with a small brush. When this precaution is taken, 
all parts so treated may be detached easily from the cast by heating slightly, 
after which they may be cleaned in the acid bath and replaced accurately. 
In the investment of parts which have been thus detached and replaced, 
attention should be directed to filling them completely with investment 
compound. If not well filled, air spaces may result, inviting the accumu- 
lation of heat and endangering the fusing of such parts during the solder- 
ing process. 
Whenever a more than ordinarily smooth cast of investment compound 
is desired, a well-defined surface detail is to be obtained by first filling the 
impression with a thin mix of cast plaster; then inverting the impression 
until only a thin surface coating remains, when it is poured immediately 
with investment compound. The resultant cast will possess all of the 
advantages demanded by the requirements of accuracy and of heat-with- 
standing properties. 
Removing Wax. When the investment has become thoroughly 
crystallized and has been trimmed to the desired form and size, the wax 
should be removed by pouring boiling water over it. All thin, overhang- 
ing edges of investment should be trimmed away carefully, the parts to be 
assembled properly fluxed, the cast placed over a flame, and heated 
gradually. 
Requirements of Investment Compounds. 
Good, reliable investment compounds, adapted to the requirements of 
crown and bridgework, must possess the following physical properties: 
First: They must withstand heat successfully. 
Second: They must offer a minimum of expansion and contraction 
properties. 
Third: They must be strong inherently. 
Heat. The property of withstanding excessive heat is essential be- 
cause the investment compound is to be subjected to a degree always equal 
to the fusing point of the solders used in the final assemblage of the parts. 
To possess this property the compound necessarily must be composed 
largely of such refractory and infusible ingredients as will not be subject 
to any appreciable change under the influence of the required heat. Com- 
pounds which will subscribe to these requirements are necessarily poor 52 
CROWN AND BRIDGEWORK 
conductors of heat, but where such an excessive degree of heat is required, 
conductivity is a negative factor. 
Shrinkage and Expansion. A minimum of non-shrinkage and non- 
expansion properties is important because all of the accuracy to be ob- 
tained in preserving the relationship of the parts to be assembled depends 
entirely upon, and is insured only in proportion to the degree to which 
these properties are possessed by the compound. 
Strength. The element of inherent strength is an important require- 
ment of all investment compounds, and must obtain in order that the in- 
vestment may retain its given form, and support and sustain the various 
physical changes which take place in the process of heating, soldering and 
cooling. 
Character of Investment Compounds. Two general classes of in- 
vestment compounds are used, each possessing different physical properties 
and characteristics, and each useful for the respective purposes for which 
it is intended. 
These classes of compounds are: First, those that possess the physical 
property of crystallization at normal temperature; and, second, those which 
do not crystallize and are used in a semiplastic state and which are hard- 
ened subsequently by burning or heating. 
Crystallizing Compounds. An investment compound that crystallizes 
without heating offers the greatest field of usefulness, and is adapted more 
universally to all classes of work. Its use is indicated generally for the 
purpose of obtaining casts from plaster impressions where inherent 
strength is necessary. It is used also for all other purposes where a defi- 
nite form is to be given to and must be maintained by the investment. 
The property of crystallization, however, is obtained by the incorpo- 
ration of plaster of paris with the other more refractory and infusible 
ingredients. And as plaster of paris will not withstand heat, and is 
disintegrated at a very low temperature, it is used only as a binder and 
as a means of imparting the property of crystallization to the compound. 
Beyond this, the incorporation of plaster of paris is harmful and its 
presence subtracts from the desired physical properties of these com- 
pounds in all other directions. 
Non-crystallizing Compounds. That class of compounds known as 
non-crystallizing compounds do not contain plaster of paris. They are 
used in the semiplastic state and are hardened by burning or heating. 
These compounds, under the influence of heat, shrink and expand to 
a lesser degree than those which contain plaster of paris and crystallize. INVESTMENT AND INVESTMENT COMPOUNDS 
53 
Their use, therefore, whenever indicated insures a maximum of accuracy 
in the assemblage. Their field of usefulness is confined to the assemblage 
of such units as may be held in proper relationship with hard wax, 
invested in a semiplastic mix of the compound, and then placed imme- 
diately over a flame, and heated with a slowly increasing temperature, 
the wax being burned out simultaneously. A fine wire mesh is useful 
as a means of sustaining the investment while heating and soldering. 
Drying and Heating. The drying and heating of an investment is 
important. Both classes of compounds contain water of crystallization 
and this must be evaporated or driven off slowly and gradually The 
investment should, therefore, be placed over a low flame at first, and 
the heat increased slowly until thoroughly dry, after which the tempera- 
ture may be raised more rapidly until the case is well heated and ready 
for soldering. CHAPTER VII. 
SOLDERING. 
Soldering is an art. It is an art that requires special skill, and an 
art that presents a fertile field for the acquirement and development 
of skill in many lines of effort. 
Metallurgy teaches that soldering is the physical process of uniting 
metals by the superficial alloying of one with another. Or, the process 
of uniting metals by the fusion of one to another, one being slightly 
more fusible than the other. 
Whether this process be executed by the itinerant tinsmith in the 
simple act of mending his wares, by the modern plumber in the more 
difficult feat of “wiping a joint,” by the expert gold and platinum smiths 
in their highly artistic lines of work, or by the skilful dentist in his 
particular field of effort, the process of soldering is always an interesting 
procedure. 
The special field of crown and bridgework offers almost unlimited 
opportunities and possibilities for the acquirement, development and 
display of skill in the art of soldering. And versatility in skilful attain- 
ments along these lines must include this art, because skill in designing 
and skill in effecting accuracy of adaptation are evidences of wasted 
effort and energy only, unless they be combined with skill in assembling; 
for without skill in assembling, the finished product is faulty. 
But soldering is not the work of an automaton. Nor may its highest 
possibilities as an art ever be reached if it is attempted in a perfunctory 
manner. Once the lesson has been learned, however, the technical details 
of procedure are simplified and soldering becomes easy. 
To this end the dentist cannot apply himself, or herself, too closely 
in an effort to learn the lesson, thus to become, if not expert, at least 
sufficiently skilled, to render the procedure one of simplicity and ease, 
thereby reducing to a minimum all attending dangers and eliminating 
entirely all possibilities of failure. 
These possibilities will result from and follow a broad and compre- 
hensive knowledge of the basic requirements, and a careful observation 
of all essential details fundamental to success. 
54 SOLDERING 
55 
Basic Requirements. 
The basic requirements which must be observed are as follows: 
First: Freedom from oxidation. 
Second: Apposition of surfaces to be united. 
Third: Proper application and distribution of heat. 
Fourth: Use and proper application of flux- 
Freedom from Oxidation. The first essential requirement is that 
of freedom from or removal of oxidation. As all metals oxidize under 
the influence of heat, and as solder will not attach to nor alloy with an 
oxidized surface, all surfaces of metal to be united, or upon which solder 
is to flow, must be clean and free from oxidation. 
And this applies also to the surfaces of the solder itself, because solder 
is even more susceptible to oxidation, for the reason that it contains a 
greater proportion of base metals as an alloy, and base metals oxidize 
more readily than do the noble metals. 
It is apparent, therefore, that all surfaces of the metals to be united, 
and of the solder which is to unite them, should be perfectly clean and free 
from oxidation at all times during the process of soldering. 
This cleanliness of surfaces and this removal of oxidation may be 
effected either by scraping or filing, or by immersing in the acid bath. 
Acid Bath. The acid bath is the quickest and most effective way 
of removing oxidation and all traces of extraneous and foreign matter 
from the surfaces of metal. 
For this purpose hydrochloric or sulphuric acid, diluted with equal 
parts of water, is used. Hydrochloric acid is preferable, because it is a 
better solvent of the silicates and of the flux used in soldering. It should 
be kept in a suitable container, such as the ordinary procelain evaporating 
or Petri dish, having a lid or cover. 
For the simple soldering of bands and all small pieces where no 
investment is used, the parts may be cleaned effectively by heating them 
to a cherry-red and then plunging them into the acid bath at normal 
temperature. 
But if heating directly in the flame is not indicated because of the 
size of the piece, or because of the presence of porcelain teeth or facings, 
it is necessary to place the bath containing the work over the flame and 
to allow it to simmer or, perhaps, even to boil until the parts are thoroughly 
clean. 
Precautions. When thus properly cleaned, all traces of acid should 
be removed immediately by immersing in a solution of sodium bicarbonate, 56 
CROWN AND BRIDGEWORK 
followed by the copious application of water. If this precaution be not 
taken and the parts again be subjected to heat while any traces of acid 
remain upon their surfaces, the salts of the baser metals will be precipi- 
tated and any subsequent soldering made exceedingly difficult, if not 
prevented entirely. 
Apposition. As a means of facilitating their union, apposition of, 
or close contact between, all surfaces to he united should obtain always. 
Solder may be made to flow over clean, properly fluxed surfaces, 
and sometimes to flow uphill or against gravity, but it balks at jumping 
over a space. 
Therefore, when the desired relationship between the parts to be 
united will not admit of direct apposition, or of close contact between 
them, any existing space should be filled in with small pieces of wire, 
or plate, closely fitted in such manner as to fill the space and restore 
apposition. 
These supplementary pieces thus fitted into spaces over which solder 
is to flow are called “Dutchmen” by the manufacturing jeweler, and their 
use will facilitate the soldering process. 
Application and Distribution of Heat. The proper application and 
distribution of heat is a consideration of the greatest importance in solder- 
ing. Because of a failure to recognize, appreciate and observe the re- 
quirements in this regard, much discouragement often follows, and much 
unnecessary and useless effort is often expended. 
To insure successful results, it must be remembered that soldering is 
the process of alloying. And, to make alloying possible, all surfaces to 
be alloyed must he exposed freely, to be adequately and uniformly heated. 
Also, it follows that these surfaces must be heated to a temperature 
slightly exceeding, or at least equal to, the degree of heat required to 
fuse the solder, before the solder will unite or alloy with the metal. 
This means that the case to be soldered, whether it is invested or not, 
must be properly, uniformly and adequately heated over the flame, or 
with the blowpipe, or both, before any effort is made to flow the solder. 
If this requirement of heat is observed properly, and then if the 
parts are fluxed properly, the process of soldering is made simple. 
Use and Proper Application of Flux. Attention has been directed 
previously to the oxidation of metals under the influence of heat, and 
to the necessity of removing, reducing, in so far as possible, and pre- 
venting their oxidation in the process of soldering. What is known as 
a “flux” is used for this purpose. 
The flux, fusing at a low temperature, protects the surfaces to be SOLDERING 
57 
soldered from oxidation by fusing over and upon them, and, by thus 
keeping them clean, the process of alloying, or soldering, is aided and 
made possible. 
It is equally necessary, also, that each piece of solder to be used should 
be treated similarly, for, being a lower grade of alloy, it is oxidized more 
easily. And when the solder is not so treated, the oversight frequently 
might cause much obstinacy in fusing, and demand a greater degree of 
heat than otherwise would be required. 
Borax. Borax is used generally for this purpose and meets all 
requirements. It should be made into a thick, creamy paste and applied 
Fig. 24. 
to all surfaces upon which solder is to become attached before they are 
heated. A convenient container and a brush of proper size are illustrated 
in Fig. 24. 
The use of dry, powdered borax is objectionable, and the use of a 
greater quantity than necessary should be avoided. Either is dangerous 
in invested cases because when first heated it expands to such extent 
as to endanger the integrity of the investment and the relationship of the 
parts. 
Liquid Flux. Liquid flux, which is a saturated solution of equal 
parts of borax and boric acid in water, is a convenient form of flux for 
soldering simple bands and small pieces, where no investment is required. 
Technic of Soldering. 
Fortified with a knowledge of the basic requirements, the lesson of 
soldering, as it applies to crown and bridgework, may be learned by a 
careful observation of the various technical procedures involved. 
Soldering Without an Investment. The simplest form of soldering 
presents when the proper or desired relationship between the surfaces or 
parts to be united may be sustained during the process of soldering with- 
out resorting to an investment. 58 
CROWN AND BRIDGEWORK 
Soldering without an investment is accomplished much 
more easily than when an investment is used, because less 
heat is required; and its application may be made more di- 
rectly and may be distributed more uniformly. 
Fig. 25. 
The simple soldering of bands, copings, dowels, or any 
and all other parts requiring no investment may be done 
directly over the flame and often without the use of the 
blowpipe. 
In soldering directly in a flame, however, it is necessary 
to know something about the varying degrees of intensity 
of heat developed by a flame. The Bunsen burner will be 
used, for example, though the flame of an alcohol burner— 
from the viewpoint of the flame itself—is the same. Small 
pieces of work may be soldered in an alcohol flame, but a 
Bunsen burner, because of affording a greater volume and a 
more concentrated intensity is more generally useful. 
Flame. The flame of a Bunsen burner consists of an 
outer sheath, varying in color from a dark blue at the base 
to a yellowish white at the point. This outer sheath envel- 
Fig. 26. SOLDERING 
59 
ops a central cone of light-bluish color; at the apex of this central cone is 
the greatest degree of heat. (Fig. 25.) 
Hence, all parts to be soldered should be carried to a point in the 
flame immediately over the apex of this central cone. The work should 
be grasped firmly with small pointed pliers at a 
point on its surface which is removed as far as 
possible from the immediate point of solder- 
ing. This precaution is necessary, for the 
pliers will absorb heat, and the closer they are 
to the point of soldering the greater will be 
the heat required. Steel pliers are used gen- 
erally for this purpose. (Fig. 26.) Nickel 
pliers, however, would be better, for nickel 
would not absorb the heat so readily as it is a 
poorer conductor than steel. 
When the parts to be soldered are properly 
and securely grasped thus (Fig. 27), flux 
should be applied to the surfaces upon which 
the solder is to flow, carried to the flame and 
fused; and the solder, also fluxed properly, is 
then placed in position so as to be in contact with the immediate surfaces 
to be united, and then fused. Care must be exercised to remove the work 
from the flame as soon as the solder flows, because, the object being: ac- 
Fig. 27. 
Fig. 28. 
complished, any additional heat beyond this requirement would only invite 
the fusing of the parts themselves. 
Mouth Blowpipe. As a rule, a simple mouth blowpipe, such as is 
used commonly by jewelers (Fig. 28), will answer all purposes, and the 
soldering frequently may be accomplished by means of the flame alone 
and without the aid of any form of blowpipe. A small bench blowpipe 60 
CROWN AND BRIDGEWORK 
used in combination with compressed air is useful, especially because it 
gives the operator free use of both hands. 
Soldering with an Investment. Whenever an investment is re- 
quired as a means of sustaining the relation of the parts, the process of 
soldering, necessarily, is more difficult and the requirements more exact- 
ing, but more difficult and more exacting only because greater heat will 
be required: and greater heat is made necessary only because of the 
Fig. 29. 
presence of the investment, which must also and always be heated 
adequately before any attempt is made to flow the solder. 
Therefore, when the invested case is trimmed properly, fluxed properly 
and otherwise is ready for soldering, it should be placed on a soldering 
mesh, over a good-sized flame (Fig. 29), and allowed to remain until 
heated thoroughly throughout. And the more thoroughly the case is 
heated before attempting to solder, the easier will be the process of 
soldering. And, further, the larger the case, and the larger the invest- 
ment, the more heat and the more time will be required. 
When the case is heated properly, thus, over the flame, it is ready 
then for the blowpipe. 
Combination Blowpipe. What is known commonly as the “com- 
bination” blowpipe is used in all cases requiring any very great degree 
of heat, and always when an investment is necessary. (Fig. 30.) SOLDERING 
61 
The combination blowpipe, used with illuminating gas, may be operated 
by means of the mouth, bellows, or compressed air, at the pleasure and 
convenience of the operator. In the absence of illuminating gas, various 
Fig. 30. 
Fig. 31. 
forms of gasoline blowpipes, operated by means of the bellows, may be 
used. (Fig. 31.) 
Management of Solder. The solder to be used should be cut into 
pieces as large as may be convenient, well fluxed, placed in position on the 62 
CROWN AND BRIDGEWORK 
surfaces to be soldered, and a moderate-sized, pointed flame from the 
blowpipe then directed upon the whole. A large or “brush” flame from 
the blowpipe is useful only for the purpose of primary heating. 
In fusing the solder, a small, pointed flame from the blowpipe should 
be directed over and upon both the parts to be united and the solder; 
and it must be remembered, that all surfaces upon which the solder 
is to flow must be heated first to a degree equal to the fusing point of 
the solder before the solder will flow smoothly upon or attach itself to 
them. 
As the solder begins to fuse and flow nicely, the flame from the 
burner underneath may be reduced in volume and the flame from the 
blowpipe directed upon the parts and continued until all of the solder, 
which the requirements of strength and contour demand, has been added 
and fused properly. 
Balling Up of Solder. Whenever the solder will not behave thus, 
when it will not flow smoothly and attach itself without trouble, or when- 
ever it persists doggedly in fusing within itself and assuming globular 
form, or shaping itself into spheroids, which is commonly termed, “balling 
up”—positive evidence is presented that the parts to be soldered are not 
yet uniformly and adequately heated. 
Effect of Gravity. In soldering large cases, and particularly if they 
involve the anterior teeth where the curvature is great, it is frequently 
necessary to change the position of the investment as the process of 
soldering progresses. This change is necessary as a means of observing 
the law of gravity and of retaining the solder at the desired point while 
it is yet in the fluid state. This feature should be observed to a greater 
or lesser extent in all cases. 
Soldering Porcelain Facings. Porcelain facings rarely, if ever, 
should be subjected to the heat of soldering. This statement does not 
imply that porcelain facings which have pins made of platinum, or of any 
of the precious metals baked in them, should not be used. But it does 
mean that when they are used they should be attached to their supporting 
structure by cementation, or other means which will not require that they 
be soldered. Soldering, at best, always weakens porcelain facings, and 
the process of soldering invites the possibility of fracturing them. 
This possibility is due to the very marked difference in the physical 
properties of the porcelain on the one hand, and of the metal pins on the 
other hand. Porcelain absorbs heat slowly and gives it off slowly, while 
the metal pins absorb heat rapidly and give it off rapidly. 
Hence, in soldering porcelain facings, the utmost care must be exer- SOLDERING 
63 
cised in applying heat in such manner as to insure the expansion of the 
porcelain previous to, or at least simultaneously with, the expansion of 
the pins. This is necessary in order that the porcelain may be able to 
receive and accommodate the expansion of the pins. Otherwise, uneven 
expansion will occur and the facing, being a friable substance, may be 
fractured thereby. 
The same precautions must be observed in cooling after soldering, 
and for the same reasons. Therefore, when porcelain facings are to be 
soldered, the investment should be heated slowly and the temperature 
raised gradually; and when the soldering has been completed the same 
care in cooling must be observed. 
It is necessary to note, also, that no overhanging edges of backing 
are permitted to remain in contact with porcelain facings which are to 
be soldered. The shrinkage of the solder in cooling, irrespective of the 
care given, invariably will cause a degree of impingement upon the porce- 
lain which will result in fracture and which can be overcome only by 
avoiding overhanging edges. 
Soldering Gum Block Teeth. If single porcelain facings having 
metal pins baked in them should be subjected rarely, if ever, to the heat 
of soldering, it is equally certain that gum block teeth having similar 
pins, should almost never be soldered. 
And yet their use may be indicated, in very rare instances, where 
the piece must restore excessive absorption, and where the best result 
from an esthetic point of view may result only by using gum block teeth. 
Gum block teeth may be soldered successfully, by backing separately 
each tooth contained in the block, and by not having contact between these 
separate backings. This precaution will assist in accommodating shrink- 
age, and thus provide against fracture. 
Shrinkage of Solder. The shrinkage of solder is an element which 
cannot be overcome. It cannot even be reduced, but it can be guarded 
against. All solders shrink more than do the basic metals, because they 
contain a low-fusing, base metal alloy. 
To guard against any possible change in the relation of the parts 
to be assembled by soldering, it should be observed: First, that the 
parts are in close apposition; and, second, that only a minimum of 
solder should be fused, or be carried to the fluid state at any one time. 
In work having several units to be assembled, therefore, the units 
should be assembled in small sections first, using a solder of a higher 
grade than that which is to be used in the final assemblage. By this 
means, when the sections are assembled finally into one piece, the quantity 64 
CROWN AND BRIDGEWORK 
of solder required to effect the assemblage and which must be brought 
to the fluid state at this time will be reduced, and the dangers from 
shrinkage lessened correspondingly. 
Cooling After Soldering. When the process of soldering has been 
completed, the heat should be reduced slowly in order to avoid too rapid 
contraction. When the temperature will permit handling, the invest- 
ment should be broken away and the case subjected to the acid bath. To 
cool slowly is particularly necessary where porcelain is used. 
Fig. 32. 
Pure Gold as a Solder. In the use of pure gold as a solder for 
platinum, very little flux is required, because the degree of fineness of 
both metals decreases the tendency to oxidation. Pure gold does not 
fuse and flow so easily nor so readily as solder, however, and, therefore, 
greater heat is required- 
If no investment, or merely a very small one, is necessary, pure gold 
may be fused with the combination gas or gasoline blowpipe and the 
bellows, or compressed air; or, with the oxyhydrogen flame. But, what- 
ever may be the source of heat production, the gold must be thoroughly 
fused and practically alloyed with the platinum if any degree of strength 
in the union of the parts is required, and is to obtain. Hence the plati- 
num must be brought to a very high degree of heat and this heat must 
be maintained during the flowing of the gold used as a solder. 
Platinum Solder. For all forms of platinum work, where any great 
degree of strength in the soldering is required, or where a greater degree 
of infusibility is demanded, both may be obtained by the use of platinum 
solder. 
Platinum solders, varying from ten per cent, to twenty-five per cent, 
of platinum in pure gold, are made for such purposes. These solders SOLDERING 
65 
are to be fused successfully on\v by means of the oxyhydrogen blowpipe. 
Hence, no advantage is obtained by using less than twenty-five per cent 
and this alloy should be the standard platinum solder. 
Oxyhydrogen Blowpipe. For all forms of soldering where either 
pure gold or platinum solder is used, a more intense and more concen- 
trated flame than is afforded by the combination gas and air blowpipe 
is required. 
Nitrous oxid gas in combination with illuminating gas produces a 
flame of great heat intensity. This is known as the oxyhydrogen flame. 
An oxyhydrogen blowpipe is a simple, inexpensive and quite necessary 
part of the equipment for doing soldering of this character. A simple 
form of blowpipe is illustrated in Fig. 32. 
A proper manipulation of the oxyhydrogen blowpipe involves the 
problem of obtaining perfect combustion. 
Sweating Method of Soldering. In soldering, the process known as 
“sweating” is often useful. “Sweating” solder means that the solder is 
fused only partially; or, that it is fused only until it alloys with or attaches 
itself to the metal, without being brought to the fluid state. 
This procedure is useful in many kinds of repair work where contact 
of the parts to be united does not present, or in covering up or filling 
in pits, holes and perforations. And, also, in instances where the complete 
fusing of the solder might endanger the relationship existing between 
the parts by the fusing of the parts, or the refusing of the solder used 
previously. 
In “sweating” solder, every requirement of soldering should be ob- 
served, except that of bringing the solder to the fluid state. 
To Prevent Unsoldering. Some means of preventing the refusing 
of solder previously used is often a very desirable, and even necessary, 
precaution to be observed. 
This may be accomplished by painting any surfaces of metal or solder 
with an anti-flux, such as a paste of precipitated chalk, whiting, plumbago, 
or crocus, before heating. By this means the refusing of solder pre- 
viously used is prevented, and any danger of destroying the existing 
relationship of parts is thus largely, if not entirely, overcome. 
Base Metal Contamination. In using gold and platinum alloys of 
any kind, and particularly when they are to be subjected to the heat of 
annealing or of soldering, care should be exercised at all times to prevent 
any possibility of contamination by base metals. 
The presence of any of the lower fusing base metals in contact with 
gold or platinum, when heated, endangers the fusing of these metals 66 
CROWN AND BRIDGEWORK 
and destroys their integrity. Contact with mercury, which is absorbed 
rapidly, is dangerous also, and should be avoided. 
Any contaminating influence of the base metals may be overcome 
if they are removed by boiling in acid before heating, either in the flame 
or with the blowpipe. 
Autogenous Solder. Autogenous soldering is the process of uniting 
surfaces of metal by immediate interfusion, without the use of a lower 
grade or more fusible alloy. The procedure offers no advantage, except 
that a joint made in this manner is not increased in stiffness or thickness. 
In executing the process of autogenous soldering, the surfaces, or 
edges, to be united, must be retained in close apposition, must be fluxed 
properly, and then heated carefully until superficial fusion unites them. 
The dangers are greater than are the advantages thus to be obtained. 
Liquid Gold Solder. A solution of gold known commercially as 
“liquid gold” solder may be used in soldering platinum, and all karats of 
gold. In its use the surfaces to be united must be placed, and held, in 
close contact. The liquid solder is then painted on with a brush and 
fused over a Bunsen burner. No flux is necessary. 
The use of liquid solder would be a means of facilitating autogenous 
soldering, but otherwise no advantage obtains. 
Soft Soldering. Soft soldering means the uniting of parts or sur- 
faces with a low-fusing, base metal alloy called “soft” solder. Except for 
emergency or temporary work, “soft” soldering is seldom indicated in 
dental work. The alloy used most commonly for soft soldering is com- 
posed of equal parts of tin and lead, though any of the fusible alloys 
will answer the purpose. Zinc chlorid is the flux. 
The necessary heat is applied usually with a soldering iron, or a small 
alcohol or Bunsen flame may be used. 
Application of Electricity. The wonderful advancements made in 
the application of electricity to heat-producing purposes makes it reason- 
able to expect that this clean and refined method of heat production will 
eventually be applied successfully to both soldering and casting. CHAPTER VIII. 
CASTING. 
Casting is also an art. History teaches that the casting of metals 
was an ancient art, but its application to dentistry is modern. 
With the advent of the application of the casting process to dentistry, 
former methods of practice were revolutionized; text-books were re- 
written, and results more certain and more definite were made possible 
and more easily accomplished. 
And, yet, the casting process is not necessarily a method which affords 
only the “easiest way,” nor is it a lazy man’s method. Its successful 
application to the field of crown and bridgework demands all of the 
painstaking care, all of the close and keen observation of minute detail, 
all of the talent and all of the skill that is required in the successful 
application of any combined artistic and mechanical procedure. 
The application of the casting process involves making the original 
pattern in wax and reproducing the original wax pattern in metal. 
Wax is a plastic and easily manipulated substance, but since the 
reproduction in metal can never be more perfect nor more accurate than 
was the original wax pattern, it is apparent that quite as much skill 
must be displayed in making the wax pattern as will be demanded in the 
application of the process by which its reproduction is insured. 
Records show that ancient and primitive efforts in casting metals 
embraced the wax pattern; the investment of this pattern; the burning out 
or the disappearance of the wax by the application of heat; and the re- 
sultant mold in one single unit. But these efforts were directed along 
purely artistic lines. The designs and the castings made were for artistic 
and ornamental purposes only, and were not made with any idea of fitting 
anything. 
The possibilities of making these castings to fit something, or of ob- 
taining accuracy of adaptation in casting probably were not even con- 
ceived. At least, it is not recorded in the early history of casting that 
any effort was made to combine the possibilities of making the pattern in 
wax and reproducing it in metal, with the result of obtaining a casting of 
definite form which would fit accurately to something possessing a given 
and definite shape. 
67 68 
CROWN AND BRIDGEWORK 
The conception of the idea of making a wax pattern in a mold of 
definite form and shape, and then of reproducing it in metal by the casting 
process, and of reproducing it in such a manner and with such accuracy 
as to have the reproduction fit the original mold, or its replica, was re- 
sponsible first for the introduction of the application of the casting 
process to dentistry. 
An immediate recognition of the advantages obtainable inspired the 
development of a technic which would insure success in its application. 
And, as a result of this inspiration and of the original development 
of a successful technic by Dr. William H. Taggart, the casting process 
is recognized now as being generally applicable to an almost unlimited 
field of usefulness in dentistry. It is indeed the very foundation of mod- 
ern successful achievements in crown and bridgework. 
The Casting Process. 
The advantages offered by the application of the casting process to 
crown and bridgework, using former methods of procedure as a basis of 
comparison, may be enumerated as follows: 
First: Accuracy of adaptation. 
Second: Increased opportunities for obtaining desired form and 
contour. 
Third: The use of alloys of higher grade or better quality. 
Fourth: Simplicity and definiteness of technic. 
Application. The casting process may be applied to almost any of 
the methods of construction in crown and bridgework. It is applicable 
equally to the simplest type of crown, or the simplest form of attach- 
ment for bridgework; or to the most extensive and complex requirements 
of bridgework, either of fixed or removable type. 
Its field of usefulness practically is unlimited, and its range of suc- 
cessful application is limited only by the acquirement of the necessary 
skill, and the development of a technic which will preclude failure and 
insure success. And these will accrue from the practice of observing 
all of the most minute details most carefully, and from an effort to 
standardize the technical details of procedure involved. 
Technic. A technic which will insure success in casting cannot be 
standardized and made applicable to all alike. The personal equation 
enters into the execution of all mechanical pursuits so largely that it 
renders any effort-toward this end impracticable. 
But a study of the basic principles, and a strict adherence to the CASTING 
69 
basic principles will aid very materially in the development of an indi- 
vidual technic that will be successful in the hands of the person who 
develops it. 
During the acquirement of a successful technic by any one, failure 
must be expected at times, and the only way to avoid failure is to profit 
by it. Study the cause of the failure and eliminate the possibility of a 
recurrence due to the same cause. 
The primary consideration, essentially, is a knowledge of the require- 
ments of the wax pattern and of the methods by which the pattern may 
be secured in the best manner. Two methods of procedure are in vogue. 
These are known as the direct method and the indirect method, and each 
has its respective field of usefulness. 
Direct Method. The method known as the direct method is that 
in which the wax pattern is made directly into or upon the natural tooth, 
or root, in the mouth. 
For the reason that no reproduction is ever as accurate as the original, 
the direct method afifords some advantages. But the direct method is 
limited in its application, and is successful only in single units, such as 
inlays, and in some forms of partial or full crowns. 
When the opportunities present for obtaining the required accuracy 
of adaptation directly in the mouth, and when they present with every 
assurance of success, the direct method is indicated. 
In its application, the pattern always should be made with a wax 
sufficiently hard to withstand the influence of body temperature. This 
is essential in order that the pattern may be handled in the fingers without 
danger of warping or distortion. Any wax which is adapted to this 
purpose is to be heated best and most uniformly in hot water. 
Indirect Method. The indirect method is the method universally 
used in crown and bridgework, and that by which the best results are 
to be obtained. This method is indicated in all cases where the pattern 
which is to be made involves more than a simple, single unit. 
The indirect method requires: First, a good, accurate impression; 
and, second, a good, accurate cast. 
Impression Compound Impressions. In all cases where only a single 
unit is involved, the best, smoothest and most reliable impression is to 
be obtained by the use of a hard grade of impression compound which 
is prepared in stick form specially for this purpose. This special com- 
pound should be used in conjunction with a small seamless band, which 
has been adapted previously and properly to the requirements of the 
case. (Fig. 33.) 70 
CROWN AND BRIDGEWORK 
Amalgam Casts. The most accurate, reliable and indestructible cast 
may be obtained by filling this compound impression with a good, quick- 
setting amalgam alloy. To obtain such a cast the excess compound should 
be cut away from the copper band, and the band with the impression 
should be invested in plaster of paris in such manner as to form a matrix 
for the amalgam. The impression is pressed down into the plaster so as 
to afiford extra height to the amalgam cast. (Fig. 34.) When so invested 
a good grade of quick-setting amalgam alloy should be mixed properly 
Fig. 33- 
and packed carefully into the impression, completely filling the mold 
formed by the impression and the surrounding plaster. 
When the amalgam has crystallized, the plaster matrix should be 
broken away, and the amalgam cast and compound impression placed in 
hot water until the compound is softened sufficiently to admit of its easy 
removal from the cast. 
If the compound impression has been taken with sufficient care 
to be accurate and with sufficient care to possess smooth and definite 
outlines, the resulting amalgam cast will require no finishing. Any surplus 
of amalgam, however, which might interfere with a free exposure of 
the outlines of the surfaces and margins to which the adaptation is to 
be made, may be removed with stones or disks. (Fig. 35.) 
Indications. A cast made of amalgam and obtained in this manner 
is indicated in all cases involving only a single unit. This includes casts 
of the basal ends of roots, and of desired tooth surfaces and tooth out- 
lines for all forms of inlay and partial crown restorations of any type. 
Making Wax Pattern. When the amalgam cast is prepared thus, 
all surfaces to which casting wax is to be molded in making the pattern 
should be lubricated with thin oil. A hard casting wax should then be 
melted on a spatula, poured into the mold with some excess, and, when 
cooled, carved and trimmed to the desired outlines and proportions. A 
softer wax might be adapted properly, without melting, but better results 
always result from the use of a hard wax. CASTING 
71 
If the amalgam cast is an accurate reproduction, and if the wax 
pattern is made with care, the possibilities of obtaining an accurate casting 
are favorable, provided that all details incident to the requirements of 
casting are observed carefully. 
When expense is of no special consideration, and where a maximum 
of accuracy and indestructibility in the cast is desired, amalgam casts 
are useful also in the application of the indirect method to the making 
Fig. 34- 
Fig. 35- 
of patterns for castings which involve more than a single unit, or for 
castings of any size. 
Plaster Impressions. For castings involving two or more units, 
and for castings embracing all forms of basic structures, such as saddles, 
accurate results will be obtained in a quicker and less expensive manner 
by taking the impression in plaster, and by making the cast either of 
plaster or of investment compound of a kind which crystallizes. 
A plaster cast usually presents a smoother surface, however, than 
one made of investment compound; hence, unless some soldering is to 
be done on the cast, which is seldom, if ever, indicated, a cast made of 
plaster meets all the requirements necessary for making the wax pattern. 
Casts Made of Plaster or Investment Compound. When a cast, 
made either of plaster or of investment compound, has been obtained 
and possesses sufficient accuracy of detail for the purpose of making the 
wax pattern, the outline of the pattern first should be traced upon its 
surface. This tracing is done best with an indelible pencil. The surface 
should then be treated with some form of varnish, or with a thin oil, 
as a means of preventing the wax pattern, which is to be molded upon 
it, from adhering to it. 
Making Wax Pattern. The pattern should be made of casting wax, 
carefully molded to the desired outline, or form, and trimmed and carved 72 
CROWN AND BRIDGEWORK 
to meet the requirements. Where considerable contouring and some 
strength is required in the pattern, a hard casting wax, softened in water, 
should be used. For basic structures, such as saddles, etc., a casting 
wax, made in thin sheet form, is best adapted to the requirements. This 
may be warmed in hot water or over the flame and adapted with the 
fingers. 
Fig. 36. 
While there is very little danger of making the pattern too thin, still, 
very thin wax often should be reinforced in places. This may be done 
easily by adding a bead of melted hard wax to the surface of the softer 
sheet wax. 
This precaution serves two purposes. It insures a retention or a 
preservation of the form and shape of the pattern while it is being in- 
vested. And an additional thickness of the pattern, here and there, 
and especially in large cases, facilitates the flowing of the metal in cast- 
ing, even though this additional thickness of the casting may need to 
be trimmed down afterward. 
As a further means of preserving the shape and form of the wax 
pattern in large cases, and of preventing any distortion of the pattern 
in investing it, a thin layer of investment compound may be painted 
carefully over its entire surface, after the sprue-formers have been ad- 
justed properly and allowed to crystallize before the pattern is removed 
from the cast. This interferes in no manner with the subsequent 
complete investment of the case. 
Attachment of Sprue-formers. In castings of any size, the proper 
adjustment and proper attachment of the sprue-former is of great 
importance. CASTING 
73 
Small Patterns. In patterns ranging in size from a single unit to 
medium-sized proportions, a single sprue-former usually will meet all 
requirements. This may be of metal or of wax. If of metal, provision 
for its subsequent removal must be made. 
The size of the sprue-former must be proportionate with the size of 
the casting to be made, and its attachment to the pattern must be secure. 
The attachment should be made at a central point and upon or to a surface 
Fig. 37- 
which will not interfere with the fit or adaptation of the casting, or to or 
upon a surface which will require finishing. (Fig. 36.) 
Large Patterns. In patterns for larger castings, one or more addi- 
tional sprue-formers may aid materially in the rapidity with which the 
metal may be distributed to all parts of the mold while in the fluid state. 
Any additional sprue-formers which the requirements of the case 
may seem to indicate should be attached to the main central sprue-former 
at a favorable point, and diverge from it to a position on the pattern 
which is favorable to a uniform distribution of the metal in casting. 
(Fig- 37-) 
Use of Acetone. If the wax pattern is painted with or dipped in 
acetone just previous to investing, all extraneous matter will be removed 
quickly, the investment compound will adhere to its surfaces more closely, 
and smoother castings will result. 
Investment. When the sprue-former has been attached securely, it 
should be adjusted to position in the base of the flask (Fig. 38), and 
invested. 
Excepting in very small, simple castings, the wax pattern with sprue- 74 
CROWN AND BRIDGEWORK 
former attached, always should be placed in position in the flask, previous 
to investing. This precaution is necessary as a means of ascertaining 
that the position of the sprue-former, or the arrangement of the sprue- 
former, is accommodated by the flask. And the pattern should not come 
in contact with the flask at any point. If it should come in contact with 
the flask, a distortion of its form or a wastage of metal in casting might 
cause failure. When these precautions have been taken the pattern then 
should he invested. 
Fig. 38. 
Investment Compounds. Investment compounds adapted to the pur- 
poses of casting should possess the following physical properties: 
First: They must possess adequate heat-withstanding properties. 
Second: They should possess a minimum of shrinkage or expansion 
properties. 
Third: They should be of a texture sufficiently fine to insure a 
smooth casting. 
Fourth: They also must be sufficiently porous to accommodate and 
take care of the contained air, which must be expelled from the mold 
before the casting may be made. 
Fifth: They must be removed easily from the metal after casting. 
A compound may possess all of these combined properties. When 
one which possesses these properties is used, a successful casting, in so 
far as the investment compound is concerned, is insured. 
Vitreous Compounds. Highly vitreous compounds cannot be em- 
ployed successfully. 
The so-called “artificial stone,” and other compounds of vitreous 
character, present a density of structure which reduces the possibilities 
for expelling the contained air from the mold. This endangers the success 
of the casting. Also, they are more difficult to remove from the surface 
of the metal after casting. CASTING 
75 
The compound used should always be thoroughly mixed, but should 
never be too thick. A fluid consistency should be maintained until after 
the investment has been completed. As a means of guarding against or 
of preventing the confinement of air along the surfaces of the pattern, 
the investment compound should be applied carefully to the surfaces of 
the pattern, first using an artist’s small brush for the purpose. 
The same compound may be used throughout the investment. No 
great advantage is gained through using a finer texture next to the 
Fig. 39- 
pattern, and a coarser texture over this, provided the one compound is 
adapted to all of the requirements. 
In investing large patterns, the use of a fluid investment compound 
will be found to be necessary as a medium to prevent any distortion of 
the pattern. 
Heating Flask. The investment never should be disturbed until 
complete crystallization has taken place. After complete crystallization, 
the base of the flask should be warmed over a flame and detached, and 
the sprue-former of metal removed. (Fig. 39.) The case should then 
be heated properly and the wax burned out. 
The flask should be placed over a low flame at first and should remain 
over a low flame until all water of crystallization has been driven off 
or evaporated. Then the size of the flame may be increased gradually 
until all wax and its gases and by-products have been dissipated 
thoroughly. 
The position of the investment in its relation to the flame, or in its 
relation to the direction in which it receives the heat from the flame, is of 
no great importance, so long as it is heated more or less uniformly 
throughout. 76 
CROWN AND BRIDGEWORK 
Overheating, or heating to a red-heat, or heating to a point higher or 
beyond the point required to drive off or evaporate the water of crystalliza- 
tion and to burn out the wax and dissipate its by-products, is never 
indicated. It is always injurious to the integrity of the investment 
compound. 
Overheating also increases the degree of expansion both of flask and 
mold, and any degree of excessive or unnecessary expansion may destroy 
the continuity of the mold, and the accuracy of adaptation of the casting. 
For these reasons, it is evident that the most accurate results will 
result from casting into a mold that is only hot enough to prevent 
chilling the fluid metal, and which is never overheated nor overexpanded. 
Casting. The casting should be made as soon as the mold has been 
burned out properly and heated adequately. 
The alloy to be used in the casting always should be melted previously 
into a fresh, clean ingot of proper proportions. An ingot of alloy, 
freshly melted and cleaned in the acid bath, casts more freely and to 
more definite and accurate outlines. The use of an ingot too small, or 
of insufficient proportions, only invites failure. And an ingot too large 
is dangerous to the success of the casting when pressure machines are 
used. Any great over-surplus may clog up the air channels. And a 
sluggish, refractory alloy will not cast smoothly. 
In making the casting, the alloy should be brought to a fluid state 
as quickly as possible, and the casting should be made the moment com- 
plete fluidity obtains. Any overheating of the alloy to be cast increases 
oxidation and causes it to become more refractory, both of which result 
in a more or less indifferent casting. 
When the casting has been made, it should be allowed to cool slowly 
and to assume normal temperature before removing from the investment. 
Casting Machines. Several different methods of casting and several 
different types of casting machines involving different basic principles 
are used. These vary from the simple method of generating and con- 
fining steam to the application of centrifugal force, and include the pro- 
duction of a vacuum by the displacement of the air from the mold and 
the utilizing of pressure in various ways. 
The pressure machines in which definite, regulated pressure is obtained 
from compressed air, or gas, and the machines which utilize the prin- 
ciple of centrifugal force afford the most successful and reliable means 
of casting. This fact is proven especially in large castings. The applica- 
tion of electricity for melting purposes, used in combination with centrif- 
ugal force for casting, would be the ideal method. CASTING 
77 
In the use of any casting machine, however, the principles and the 
mechanism involved must be understood thoroughly. When these are 
understood, if the machine is kept in good order and properly and care- 
fully manipulated, successful results usually will be insured. 
Casting Flasks. Each type of casting machine usually is accom- 
panied by a special form of casting flask adapted to its use. And some of 
the larger and more pretentious machines have a series of flasks varying 
in size to accommodate the size of the casting to be made. 
Casting to Surfaces of Metal. Where it may be desirable to have 
some metal projecting from the wax pattern, and included as a 
part of it, such as pins, dowels, etc., and to cast to it, or have it picked 
up by the casting, and become a part of the casting, the procedure is 
practicable. 
It is very doubtful, however, if any actual physical union occurs be- 
tween the casting and the parts thus picked up. The attachment is purely 
a mechanical one, particularly if a high grade of alloy is used in casting. 
But if a physical union is desired, it may be obtained, first, by fusing 
solder to the surfaces to which the casting is to become attached. Or, if the 
alloy used in casting contains a considerable proportion of solder or is of 
base metal alloy, a physical union may be obtained. 
Casting to Porcelain. Castings may be made directly to and upon 
porcelain teeth and facings, but the practice offers no advantages and pre- 
sents some objectionable features. 
The difference in the physical properties of metal and porcelain, and 
the shrinkage of alloys in casting, necessarily must endanger the integrity 
of any form of porcelain subjected to these influences. And, in addition 
thereto, the same opportunities for repair, or for the replacement of porce- 
lain teeth, or facings, so used does not present. The subsequent attach- 
ment of the porcelain tooth, or facing, to the casting by means of cemen- 
tation is always to be regarded as much safer and more reliable. 
Removing Investment After Casting. Gold alloys in the fluid state 
have a great affinity for the silicates, and hence investment compounds 
which contain a large proportion of the silicates usually adhere firmly to 
the surface of the metal after casting, and much difficulty is experienced 
at times in removing all remaining traces. 
Dilute hydrochloric acid at the boiling point is a slow solvent and may 
be used successfully. Hydrofluoric acid, however, is a better and quicker 
solvent Hence, all remaining traces of investment compound may be re- 
moved most quickly and thoroughly from the surfaces of gold alloy cast- 78 
CROWN AND BRIDGEWORK 
ings by immersing them in hydrofluoric acid for a few moments. A wax 
container of suitable size and shape must be used for this purpose. 
Casting Base Metal Alloys. Base metal alloys may be cast with the 
same technic used in casting higher grade alloys and with equal success. 
Their use, however, presents no advantages over the alloys of gold, other 
than that of economy. CHAPTER IX. 
PREPARATION OF TEETH AND ROOTS. 
If the superstructure is to endure, the foundation upon which it rests 
must endure. In all engineering and mechanical pursuits in any field of 
construction work a properly prepared foundation must be recognized as 
essential to the stability and durability of the superstructure. 
And it must be recognized, also, that any skill displayed in building 
the superstructure is but a waste of energy unless equal skill is manifest in 
the preparation of the foundation which is to support it. 
Thus, it is evident, successful achievements in construction work of any 
kind will depend, primarily, upon a knowledge and application of correct 
basic principles, and upon a close observation of all of the basic require- 
ments fundamental to the proper preparation of the foundation. 
As applied to the construction and application of crown and bridge- 
work, a knowledge and close observation of all of the basic requirements 
is particularly essential, and the demands are even more exacting because 
the foundation is a part of the human body, and because the field of opera- 
tion is confined to vital tissues. * 
And, furthermore, the superstructure which is to be attached to and 
supported by this foundation must be of a character which not only will 
endure, but which will not do irreparable injury. For wherever injury is 
done, discomfort follows, health is jeopardized and failure is invited and 
becomes inevitable. 
The foundation must be prepared properly, therefore, even though the 
demands may be exacting and even though the requirements may be diffi- 
cult to meet. Hence the skilful preparation of teeth and roots which are 
to support artificial crowns and dental bridgework must be recognized 
as a primary essential to the achievement of successful results. 
Basic Principles. 
Artificial crowns of any type are attached to their supporting roots 
by two different methods. Each method involves a different basic me- 
chanical principle. 
79 80 
CROWN AND BRIDGEWORK 
The two different basic principles involved are known in mechanics 
as the telescoping and the dowel principles, and all types of artificial crowns 
are attached to the supporting tooth, or root, by either one or the other. 
The basic requirements of tooth and root preparation, therefore, are de- 
pendant, necessarily, upon the principle involved in the attachment of the 
crown to its supporting tooth or root. 
Variations. Any variation in the type of artificial crown, or any varia- 
tion in the details of construction, may require some slight variation in the 
details of tooth or root preparation, but these variations, in the main, in- 
dicate versatility of ideas only, and this versatility will not occasion nor 
demand any appreciable deviation from the basic requirements. 
Based upon the method by which the attachment is made to the sup- 
porting tooth, or root, all types of artificial crowns may be considered in 
two general classes: First, telescope crowns; and second, dozvel crowns. 
The basic requirements of tooth and root preparations, therefore, will be 
considered from the respective viewpoints of this general classification. 
Telescope Crowns. 
Any type of crown attached to the periphery of the supporting tooth, 
or root, by means of telescoping over some remaining portions of the 
natural crown, is designated as a telescope crown. 
Artificial crowns, in this classification, include full crown restorations 
made or platinum, and with or without a shoulder; all types of 
jacket crdfcms; all types of partial crowns; and all other variations of con- 
struction in and by which fixation and permanent attachment may result 
by means of the telescoping or of the overlapping of the crown upon 
the supporting tooth, or root. 
While the telescoping principle of attachment is understood generally 
as indicating the type of crown used in restoring the crowns of the pos- 
terior teeth, the same general principles apply to jacket crowns and to 
partial crown restorations upon the anterior teeth, and to all types of con- 
struction in which the attachment is made to the remaining natural crown 
of the tooth involved. 
Dowel Crowns. 
All types of crown restorations which embrace a full crown (except 
the jacket crown), and where the line of junction between the crown and 
its supporting root is at a point approximating the gingival line, may be 
designated as dowel crowns. PREPARATION OF TEETH AND ROOTS 
81 
When the line of junction is made at this point the use of a dowel 
anchored into the body of the crown, and then extending into the root 
to the required depth, is necessary to the mechanical fixation and to the se- 
cure attachment of the crown. It is necessary because the shortness of 
the root precludes utilizing the telescoping principle to any advantage, and 
because the requirements of strength and permanency in the attachment 
demand that adequate resistance to stress must be secured. 
The dowel may be a joined or a separable part of the crown, and in 
size and length it must be adequate to the requirements of strength. When 
these features are observed, a secure attachment is insured, for the reason 
that the stress imposed upon and assumed by the crown is distributed thus 
throughout the length of the supporting root to the extent to which it en- 
gages the dowel. 
Dowel crowns are indicated in all restorations where the remaining 
natural crown of the supporting tooth has been lost, or where it is sacri- 
ficed purposely, to the gingival line; and where the esthetic requirements 
demand the use of porcelain teeth, or facings, in all types of construction 
other than jacket crowns. 
The application of dowel crowns, therefore, will be confined largely 
to the restoration of the ten anterior maxillary and mandibular teeth, or 
to those teeth which are within the range of vision. 
Thus, it will be observed, the basic requirements incident to the prepa- 
ration of teeth and roots which are to support artificial crowns must vary 
necessarily with the mechanical principles involved in the method of attach- 
ment. 
Preparation for Telescope Crown with Peripheral Band. 
The telescope crown with peripheral band, commonly designated as 
the “shell” crown, when properly adapted and properly constructed, is 
probably one of the most useful methods of restoring the crowns of 
posterior teeth. 
In order that this type of crown may meet the requirements of accu- 
rate adaptation, considerable preparation of the remaining natural tooth 
crown is demanded. 
In all teeth having vital pulps the actual mechanical requirements are 
so exacting and at times so difficult as to cause considerable discomfort 
to the patient. Nevertheless, the requirements must be met properly 
at all times and in all cases. Any indifference to them, occasioned by sym- 
pathy or an inclination to treat them in a perfunctory manner, only lessens 
the possibilities for obtaining accuracy of adaptation. And accuracy of 
adaptation is fundamentally essential to success at all times. 82 
CROWN AND BRIDGE WORK 
Restoration of Continuity of Natural Crown. 
In a very large proportion of cases, where the use of a full telescope 
crown is indicated, much of the natural crown and some of its remaining 
walls have been lost through the ravages of caries. The loss of remaining 
axial walls by caries frequently carries the cavity margin beneath the 
Fig. 41. 
gingival line at some point. When this condition prevails, some means 
of effecting a permanent restoration of the continuity of the root, previous 
to its final preparation for the reception of a crown, is essential. 
In cases of this kind some means of permanent restoration, independent 
of the crown, is advantageous because of the support and protection such 
restoration may afford. If the restoration is made properly, the integrity 
of all remaining walls of the natural crown is preserved, the opportunities 
for obtaining a better adaptation of the artificial crown to’the entire cir- 
cumference of the root are increased, and a more permanent restoration is 
insured. 
Restoration with Cement. Cement will answer all requirements in 
effecting such restorations provided it may be completely covered with the 
crown, subsequently. But where the position of the cavity margin in re- 
lation to the gingiva (Fig. 40) may make it inadvisable or impossible to 
so adjust the edge of the crown to cover the cement completely and pro- PREPARATION OF TEETH AND ROOTS 
83 
tect it, the best and most permanent results are obtained through the use 
of amalgam. 
Restoration with Amalgam. In making the restoration with 
amalgam adequate mechanical retention must be insured. This may be 
obtained in vital teeth by so shaping the remaining walls of the natural 
crown as to insure retention; or, in pulpless teeth, the pulp chamber and 
root canals may be so enlarged and so shaped as to afford secure retention. 
The use of a circular band made of German-silver plate, about 36 gage, 
to act as a matrix will facilitate the making of the restoration with amal- 
Fig. 42. 
gam. When a matrix has been fitted properly and adjusted as illustrated in 
Fig. 41, the surface presenting toward the tooth to be restored should be 
covered with vaseline, melted wax, or some other medium for preventing 
its attachment to the amalgam and of insuring its easy detachment from 
the tooth and amalgam restoration after it has crystallized. As a fur- 
ther means of facilitating the removal of the matrix after crystallization, 
the amalgam never should be built up flush with the edge of the matrix. 
(Fig. 42.) 
If the walls of the remaining tooth crown are just smeared with thin, 
well-mixed cement immediately preceding the packing of the amalgam, the 
adhesive properties of the cement will strengthen the remaining walls and 
insure a closer and better adaptation of the amalgam restoration to the 
tooth. 
In instances where the entire natural crown has been lost, or must be 
sacrificed to a point approximating the gingiva, and where the use of a 
telescope crown may be desirable, one or the other of two procedures must 
be followed. 
If no part of the natural crown remains, it is evident the telescoping 
principle of attachment will not meet the requirements. Hence, if a full 
telescoping crown is to be used, either the root must be partially restored 
first, or a dowel must be used, or both. 84 
CROWN AND BRIDGEWORK 
Such restorations may be made easily by providing adequate retention 
in the body of the root, adjusting a circular matrix and then building the 
restoration to the desired extent, shape and form with amalgam. 
If opportunity for obtaining adequate anchorage of the amalgam to the 
root is not offered, or if a sufficiently secure anchorage seems to be doubt- 
ful, such an anchorage may be insured by first fitting a threaded dowel 
into one or more canals, mounting the dowel or dowels with cement, and 
then building the amalgam restoration around their projecting ends. 
(Fig. 43-) 
Fig. 43. 
When the amalgam has crystallized, the matrix should be detached and 
removed, and the restoration then thoroughly finished and polished. 
Since the crown to be adjusted subsequently can offer no greater per- 
manency, and no more freedom from irritation than is insured by the res- 
toration itself, the restoration should be properly finished before fitting 
and mounting the crown. 
Shaping Remaining Natural Crown. 
The natural crowns of typically formed teeth present their greatest 
circumference at the contact point. The gingival edge of a telescope crown 
must be adapted closely to the supporting tooth at some point between the 
contact points and the gingivae. 
Therefore it is evident that the proportions of the entire natural crown, 
or of any of its remaining axial walls, must be reduced until the greatest 
circumference presents at the immediate point to which the crown is ex- 
pected to fit. Any degree of accuracy of adaptation of a telescope crown 
to its supporting tooth, or root, is impossible unless this absolute me- 
chanical requirement is observed. 
Hence the natural crown of a tooth which is to support a telescope 
crown must be shaped in such manner as to insure accurate adaptation. 
Comfort, health, usefulness and permanency depend entirely and com- 
pletely upon the absence of mechanical irritation, and while unnecessary PREPARATION OF TEETH AND ROOTS 
85 
or ruthless mutilation or destruction of any part of the crown of a natural 
tooth is never warrantable, yet the mechanical requirements demand that 
all axial walls be reduced until the greatest circumference presents at the 
point to which the final adaptation of the artificial crown is to be made. 
In reducing the natural crowns of typically formed teeth, and in shap- 
ing the remaining walls to meet this requirement, it will be observed that 
considerable tooth structure must be sacrificed along all axial walls and 
including the occlusal surface. (Fig. 44.) The occlusal surface must be 
sacrificed to an extent that will provide adequate space for its proper 
reproduction in the artificial crown. 
Fig. 44. 
To increase further the opportunities for insuring a close and accurate 
adaptation of the artificial crown to its supporting tooth, or root, all re- 
maining axial walls should be inverted slightly, rather than made straight 
and mutually parallel. This precaution will insure the greatest circumfer- 
ence at the desired point, and thus cause the crown to fit more closely as 
it is forced to its proper position. 
If irritation is to be avoided and if health and comfort are to obtain 
and are to be maintained, the gingival edge of an artificial crown never 
should be permitted to encroach upon the investing tissues, nor to pass be- 
neath the free margin of the gingivae. This will be possible only in pro- 
portion to the favorable shaping of the tooth, or root, to meet this re- 
quirement. 
Paralleling Converging or Diverging Teeth. 
Once the normal denture has been disturbed by the loss of a single 
unit, the loss is followed by the migration of the adjacent units. They 
migrate toward the space left vacant by the missing unit, but they do not 
migrate along lines perpendicular with their long axis. Because of the loss 
of contact with the adjacent tooth the normal occlusal relationship is no 
longer sustained, and, hence, they are no longer normally fortified against 
the influences of stress. They move along the line of least resistance 
and their crowns move more than their roots. Hence they tip—converge 86 
CROWN AND BRIDGEWORK 
toward, or diverge from one another. (Fig. 45.) This tipping, or con- 
verging, or diverging continues indefinitely, or, at least, until the affected 
teeth find a relationship with their opponents which sustains them even 
though their normal functional activity may be greatly impaired or lost 
entirely. 
Fig. 45- 
This migration is to be prevented only by the replacement of the miss- 
ing unit immediately following its loss. But when immediate replacement 
is not made, and migration has started, it can be arrested and normal 
functional activity restored by the application of some form of bridge- 
work. Thus, it often may become necessary to attach bridgework to 
converging or diverging teeth as a means of preventing migration and of 
restoring functional activity. 
In such cases, all of the basic requirements incident to the preparation 
of the remaining natural crown which is to be restored as a single unit 
by means of the telescope crown, must be observed. And, in addition, the 
remaining natural crowns must be made to present perpendicular and mu- 
tually parallel lines in order that any type of restoration in which the 
telescope crown is used may be made effectively. 
Operative Procedure. In the preparation or proper shaping of the 
remaining natural crowns of molar and bicuspid teeth for telescope crowns 
with a peripheral band, the operative procedure incident to an observation 
of all the mechanical requirements is both difficult and exacting. It is diffi- 
cult particularly when teeth with vital pulps are involved, because the pa- 
tient usually and necessarily is subjected to considerable discomfort; and 
it is exacting because the requirements must be observed, irrespective of 
the degree of discomfort. PREPARATION OF TEETH AND ROOTS 
87 
The procedure may be greatly facilitated and the degree and extent 
of discomfort lessened, however, by the use of a good assortment of car- 
borundum stones which cut clean and run true; and by the use of new, 
sharp burs, when the use of burs is indicated. Vibration, and consequent 
discomfort in the use of carborundum stones, is increased or decreased in 
proportion as they may cut clean and run true. And any overheating of 
Fig. 46. 
the tooth may be avoided by the use of a spray of tepid water, directed 
upon the stone during the procedure. The use of cutting stones of any 
kind which are not mounted true, or which are so worn as to present 
an irregular cutting edge, only increases vibration and adds to the dis- 
comfort of the patient. 
The occlusal surface of all remaining walls should be removed 
to the desired point first, by using a thick-edged stone of proper diameter 
for the purpose. 
The buccal and lingual walls should be properly reduced then, and 
this may be done best, first with a thick or blunt-edged stone of proper 
dimensions, and later with a thin-edged stone. Care must be exercised to 
avoid the formation of a groove, or shoulder, and to insure a smooth, con- 
tinuous surface. 
When the occlusal, buccal and lingual surfaces have been reduced 
properly, the mesial and distal surfaces, where the greatest difficulty will 
be encountered, should be reduced likewise. For this purpose thin carbor- 
undum separating disks are most useful, and a small, cross-cut fissure bur 
may be used also to advantage. Safe-edged, side-cutting stones (Fig. 46) 
and inverted cone and other shapes of stones also are useful frequently. 
The use of enamel cleavers is seldom indicated in the preparation of 
bicuspids and molars for a telescope crown. Such instruments are not 
applicable to the removal of enamel of the density and to the proportions 
here indicated. 
When all surfaces have been reduced thus, the preparation should be 
completed by the rounding of all sharp angles. (Fig. 47.) The degree of 88 
CROWN AND BRIDGEWORK 
accuracy obtained in the completed preparation will be evidenced by the 
ease with which a measurement wire, twisted taut around the circumfer- 
ence, at the point where the edge of the crown is expected to fit, may be 
removed. 
Fig. 47. 
Fig. 48. 
Variations. Where the esthetic requirements demand the use of 
porcelain, the telescope crown, made of gold or platinum, often may be 
used in combination with porcelain facings, in which only a slight varia- 
tion in the requirements of tooth, or root, preparation will be demanded. 
The variation consists only in reducing the buccal wall to an extent 
sufficient to accommodate the presence of a porcelain facing as a compo- 
nent part of the completed crown. (Fig. 48.) This may be done after the 
requirements of preparation in all other directions, as indicated, have been 
observed. 
Preparation for Shoulder Crowns. 
The basic requirements for tooth and root preparation for shoulder 
crowns of any type fundamentally are the same as the requirements for PREPARATION OF TEETH AND ROOTS 
89 
any type of telescope crown. They differ only in the formation of a 
shoulder at the gingival line, or at a point just within the gingival border. 
Full Shoulder Crown Restorations. Full shoulder crown restora- 
tions are made of gold and of porcelain. The application of full shoulder 
crowns made of gold is confined almost entirely to the restoration of the 
molar and bicuspid teeth. Full crown restorations made of porcelain are 
not limited in their application. This type of restoration is known as the 
“jacket” crown, and is applicable, more or less universally, to the restora- 
tion of all teeth of the denture. The preparation of the supporting tooth 
is the same, practically, for either gold or porcelain, and varies only as it 
applies to the teeth involved in the preparation. 
Preparation for Full Shoulder Gold Crowns. 
In the preparation of the remaining crowns of molar and bicuspid 
teeth for the application of full shoulder gold crowns, all requirements 
incident to the reduction of the occlusal surface and remaining walls 
should be observed. 
The occlusal surface should be reduced first, using a small, thick-edged 
stone for the purpose. Except where the natural tooth crown has been 
worn so as to present a flat surface, the reduction of the occlusal surface 
should be made to follow the shape and outlines of the original cusp for- 
mation. By observing this feature, tooth structure is conserved, the pulp 
is protected better and resistance to normal stress in all directions is in- 
creased. 
The mesial and distal surfaces then should be reduced to a point just 
within the gingival border, using a thin vulcan-carborundum disk, about 
seven-eighths inch in diameter, for the purpose. By using disks of this 
kind a shoulder may be formed at the desired point, its extent being coin- 
cident with the thickness of the disk. 
The buccal and linqual surfaces then should be reduced to the required 
dimensions, using a small, flat-edged stone about one-half to five-eighths 
inch in diameter. When these surfaces are reduced thus the shoulder 
should be formed. The formation of a shoulder may be accomplished 
best by the use of small stones of cylinder shape. These stones should be 
used either in the straight or right-angle hand-piece, as the requirements 
may demand. 
When the shoulder is formed thus upon all surfaces the angles should 
be rounded and the shoulder made smooth and continuous around the en- 
tire circumference of the tooth. The angles may be rounded best by the CROWN AND BRIDGEWORK 
90 
use of fissure burs and the shoulder should be of uniform thickness, not 
less than one millimeter, nor more than one and one-half millimeters. 
(Fig. 49.) 
Where the buccal and linqual walls of the remaining natural crown are 
good, and where their conservation may be desirable, full shoulder crowns 
may be made without sacrificing these surfaces entirely by forming the 
Fig. 49. 
Fig. so. 
shoulder at any point between the occlusal angle and the gingiva. 
(Fig- 5°-) 
As any unnecessary display of gold is always objectionable, a conser- 
vation of these walls adds materially to the esthetic results. 
Either of these types of full gold shoulder crowns may be used as a 
means of restoring the tooth as a single unit, or as a means of obtaining 
anchorage for bridgework without deviating from the requirements of 
tooth preparation. 
Preparation for Partial Shoulder Gold Crowns. 
Partial shoulder crowns made of gold and possessing all of the ad- 
vantages of a full shoulder crown, together with a conservation of the 
entire buccal and labial surfaces of the supporting teeth, are used fre- 
quently. 
This type is known commonly as the “three-quarter” crown. It is not 
indicated nor used as a means of restoring the natural tooth crown as a 
single unit, but it is a most useful and valuable means of obtaining at- 
tachment to the crowns of teeth having vital pulps, for the purpose of 
anchorage for bridgework. 
The same basic requirements indicated for the preparation for a full 
shoulder crown are essential to the preparation for a partial shoulder 
crown, except that the buccal or labial surface of the supporting tooth 
is not involved. PREPARATION OF TEETH AND ROOTS 
91 
Preparation of Posterior Teeth. In the preparation of molars and 
bicuspids for partial shoulder crowns, the mesial, distal and lingual sur- 
faces are prepared in exactly the same manner indicated for full shoulder 
crowns, but some additional preparation is demanded to prevent dis- 
placement and to insure secure mechanical fixation. 
Fig. 51. 
Fig. 52. 
This additional requirement should be obtained after the shoulder has 
been formed, and consists in grooving slightly the mesial and distal axial 
walls to a sufficient depth toward the pulp, parallel with the long axis of 
the tooth, and to lines parallel to each other at a point immediately lingual 
to the remaining buccal wall, as indicated in Fig. 51. 
If the greatest distance from mesial to distal surfaces is from A to A, 
and the next greatest distance is at B, with the shortest distance at C, any 
possibility of displacement is overcome, and a secure mechanical fixation 
is insured. 
These retention grooves may be made best with a fissure bur of proper 
size and it is essential that these grooves should be placed parallel with 
the long axis of the tooth and parallel with each other. 
The typical preparation for biscuspid teeth is illustrated in Fig. 52. 
Preparation of Anterior Teeth. In the preparation of anterior 
teeth for the application of partial shoulder crowns, the basic requirements 
are the same in all details except that the mesial and distal retention 
grooves should not be placed parallel with the long axis of the tooth. 
The secure retention of partial shoulder crowns applied to anterior 
teeth will depend entirely upon the position of the retention grooves in their 
relation to the supporting natural crown; hence, their proper position is of 
great importance. 92 
CROWN AND BRIDGEWORK 
Because of the normal gingival curvature, the shortest distance from 
the incisal end to the gingiva presents at the center, labiolingually, of the 
mesial and distal surfaces of the natural crown, if measured by lines 
drawn parallel with the long axis of the tooth. If the retention grooves 
are made along lines parallel with the long axis of the tooth they are placed 
at a point where they necessarily must be the shortest. But a maximum, 
rather than a minimum length of retention grooves is necessary to insure 
Fig. 53. 
Fig. 54- 
strength in the attachment; hence, in order that a maximum of strength 
may obtain, the retention grooves must be placed parallel with the labial 
plate of enamel, as indicated in Fig. 53, A to A and not parallel with the 
long axis of the tooth as indicated in the line drawn from B to B. 
When the retention grooves are placed at this angle, Fig. 54, A, and are 
terminated in an incisal groove, Fig. 54, B, the length of the retention area 
will be nearly equal to the entire circumference of the natural crown, and 
stability in the attachment will be insured. 
Whenever the thickness of the incisal end of the natural crown will 
permit, an incisal groove made at the expense of the lingual plate of enamel 
and extending from mesial to distal angles always should be made. 
Enamel Margins. After cutting the retention grooves, the enamel 
margins and all sharp angles should be beveled slightly. No preparation 
in which the formation of enamel margins is involved is ever complete 
unless the preparation embraces the protection of all remaining short 
enamel rods. Hence, a knowledge of the histology of the teeth is essential 
primarily, in order that this protection may be supplied in all cases. 
In cases where the remaining natural crowns of anterior teeth are very 
thin labiolingually, and where no cingulum and only a gradual sloping PREPARATION OF TEETH AND ROOTS 
93 
convexity from gingivae to incisal end presents, the formation of an in- 
cisal groove may be impracticable. In such cases incisal retention may be 
abandoned and compensated for by utilizing the lingual pit. The lingual pit 
may be deepened and enlarged sufficiently to receive and engage a small 
pin, as illustrated in Fig. 55, with every assurance of affording adequate 
strength in the attachment. 
The requirements of preparation are very exacting, and, because of 
Fig. 55- 
Fig. 56. 
the size of the natural crowns, such crowns are more generally applicable 
to the upper central incisors and to the upper and lower cuspids than to 
the upper laterals and lower incisors. The typical preparation for an 
upper cuspid is illustrated in Fig. 56. 
On account of the natural tipping of the anterior teeth and the more 
perpendicular position assumed by the posterior teeth, the placing of the 
retention grooves on a line parallel with the labial plate of enamel in the 
preparation of anterior teeth and the placing of these grooves on a line 
parallel with the long axis of the teeth in the preparation of posterior 
teeth will not preclude, necessarily, the utilizing of both anterior and pos- 
terior attachments combined in one fixture. But care must be exercised, 
of course, to make the preparation in such manner as will insure a proper 
alinement of one with the other. 
Preparation for Full Shoulder Porcelain Crowns. 
Full shoulder crowns made entirely of porcelain are designated gen- 
erally as porcelain “jacket” crowns, or as a porcelain “veneer” crowns. 
Neither term is expressive of a scientific nomenclature, but by common 
usage both terms are accepted and recognized as meaning a full all-porce- 94 
CROWN AND BRIDGEWORK 
lain shoulder crown. In the absence of a more scientific term the older 
of these terms—“jacket” crown—will be used. 
All of the basic requirements fundamental to the preparation of the 
remaining natural crown for the application of a shoulder crown made of 
gold, apply to, and must be observed in, the preparation for porcelain 
jacket crowns. Indeed, the requirements are even more exacting and 
must be observed even more closely for the reason that porcelain is not an 
indestructible substance. 
On the contrary, porcelain is a friable substance, and, being friable, 
will possess strength equal to the requirements of crown restoration, 
only when it may be adequately protected against the influences of stress. 
Protection against stress will obtain from resistance to stress; and 
resistance to stress will be increased in proportion as the supporting na- 
tural crown is prepared properly to protect the porcelain restoration ade- 
quately and to insure for it a maximum of resistance to stress. 
A study of the histological structures of the teeth shows how won- 
derfully the enamel is supported and protected against stress by the forma- 
tion of the dentin. 
Therefore, since it is difficult to improve upon Nature’s plan, and since 
the porcelain restoration is to take the place of the enamel, it should be 
protected and supported in much the same manner as the enamel is pro- 
tected and supported. 
Indeed, if by some metaphysical means it might be possible completely 
to denude the natural crown of a tooth of its enamel, the normal forma- 
tion of the supporting dentin would be most favorable to the support and 
protection of an all-porcelain jacket crown. 
Hence, the requirements of preparation will be met in the most 
successful manner by so removing the enamel, and by so shaping the re- 
maining natural crown as to leave the supporting dentin much as its nor- 
mal outlines present originally. The formation of a shoulder is advan- 
tageous only as a means of afifording a definite line of junction between 
the crown and its supporting tooth. 
Because of the friability of porcelain a definite line of junction is es- 
sential to the requirements of strength. It is essential, also, to the preserva- 
tion of accuracy in the adaptation. Thin, attenuated edges of porcelain 
are brittle, and hence must be avoided. And, because of this brittleness, 
sufficient thickness must exist always to insure adequate strength. For 
this reason the preparation of a shoulder is advantageous. 
In denuding the remaining natural crown of its enamel, in properly 
shaping the supporting dentin, and in forming the shoulder, the following 
basic requirements must be observed: PREPARATION OF TEETH AND ROOTS 
95 
Coronal Preparation. First: When properly prepared, the remain- 
ing coronal proportions of the natural teeth should assume the general 
outlines of the original formation of the dentin. This preparation is abso- 
lutely necessary in order that normal resistance to stress may obtain. 
Second : When the original outline of the supporting dentin obtains, the 
remaining coronal proportions should then be tapered slightly in order 
that the greatest circumference may present at the point where the shoulder 
is to be placed. 
Third: The completed preparation must be free from all undercuts, 
and all sharp angles must be rounded. 
Shoulder Preparation. First: The shoulder should be placed 
slightly within the free gingival margin. This is necessary in order that 
the immediate joint between crown and root may be placed at a point 
where it will be both inconspicuous and immune to the action of secretions. 
Second: The shoulder should be of a thickness not less than one milli- 
meter, and should be uniform and continuous around the entire circum- 
ference of the tooth. 
These basic requirements apply to the preparation of both anterior and 
posterior teeth and to teeth having vital pulps, as well as to pulpless teeth. 
Preparation of Teeth Having Vital Pulps. In the preparation of 
teeth having vital pulps, extreme care must be taken always to avoid 
overheating, and to minimize the usual attending discomfort. Pulp vi- 
tality may be impaired or greatly endangered by overheating. In the use 
of stones the attending discomfort may be reduced and overheating may 
be prevented by the constant application of a stream of tepid water di- 
rected upon the stone while grinding. When steel instruments are used, 
compressed air played upon the tooth will answer the same purpose. These 
precautions should be observed in all cases. 
Preparation of Pulpless Teeth. Even though pulpless teeth are 
not so responsive to overheating, the same care always should be exercised 
to prevent any unnecessary discomfort and to facilitate the operative 
procedure. 
Operative Procedure. 
In the operative procedure incident to the preparation of the remain- 
ing natural crown for jacket restorations, only a few instruments are 
necessary. Too many are confusing. A good selection of stones of vary- 
ing sizes and shapes, and a few special forms of burs are all that will be 
required. 
The angle outlines should be made first and no effort should be made 96 
CROWN AND BRIDGEWORK 
to form the shoulder until the remaining natural crown has been reduced 
to the proper and desired outlines. 
Anterior Teeth. In the preparation of the incisors and cuspids, the 
incisal end of the remaining natural crown should be removed first. This 
Fig. 57- 
Fig. 58. 
edge should be cut away to a point approximating the line of junction 
between the enamel and the dentin, or to a point slightly deeper than this 
junction (Fig. 57, A to B)and it should be cut away on a plane inclining 
slightly toward the lingual surface (Fig. 57 C). A flat-edged stone from 
five-eighths to three-fourths of an inch in diameter is adapted best to 
this purpose. 
The mesial and distal angles should be removed in such manner as to 
assume a slight taper from incisal end to gingivae, as illustrated in Fig. 58. 
A thin vulco-carborundum disk, about seven-eighths of an inch in diam- 
eter, is invaluable for this purpose. 
The labial and lingual surfaces are then reduced. A small, thin, flat- PREPARATION OF TEETH AND ROOTS 
97 
edged carborundum stone about five-eighths inch in diameter will be 
found effective for this purpose. 
When all surfaces have been reduced thus (Fig. 59 A) the angles 
should be rounded. The rounding of the angles may be accomplished by 
Fig. 59. 
Fig. 60. 
using a small stone, cone-shaped (Fig. 59 B) followed by the use of sand- 
paper disks. 
The shoulder is formed immediately thereafter. Small cone- and 
cylinder-shaped stones are used to start with, and these are followed by 
the use of plain, straight-sided fissure burs. In using fissure burs, the 
tool should be placed on a line parallel with the labial surface first (Fig. 
60 A) and then forced rootwise until its end reaches the point just within 
the gingival border, at which the shoulder is to be placed. (Fig. 60 B.) 
The bur is then carried laterally (Fig. 60 C) until the shoulder is made 
continuous and of the desired thickness around the entire circumference. 
(Fig. 60 D.) 98 
CROWN AND BRIDGEWORK 
An end-cutting bur, designed for the purpose, is used to complete the 
formation by making the shoulder straight and smooth. The formation 
of the shoulder having been thus completed, sandpaper disks should be 
used to smooth and round all angles and surfaces. (Fig. 61.) 
Posterior Teeth. In the preparation of bicuspids and molars, the 
occlusal surfaces should be reduced first, and in the manner described for 
the preparation for shoulder crowns made of gold. This surface never 
should be ground off flat, except where the natural crown has been worn 
Fig. 6i. 
'down, but should be shaped to follow the planes of the original cusp for- 
mation. 
The mesial and distal surfaces should be cut away, using a thin vulcan- 
carborundum separating disk, held at such an angle in its relation to the 
long axis of the tooth as will cause these surfaces to be slightly tapered, 
and, at the same time, to make a shoulder of the thickness of the disk at 
the desired point within the gingival border. 
The buccal and lingual surfaces then should be reduced as indicated. 
The reduction of the mesial, distal, buccal and lingual surfaces thus com- 
pleted to the desired extent, the angles may be rounded and the shoulder 
upon the buccal and lingual surfaces made with small, cylinder-shaped 
stones, used in straight or right-angle handpiece as the requirements may 
demand. The shoulder then may be made of uniform thickness, and 
smooth and continuous around the entire circumference, by the use of fis- 
sure burs. 
Much of the success of porcelain jacket crowns depends upon the 
formation of the shoulder and every effort must be made to meet the 
requirements of shoulder formation with definiteness and exactness. 
Care must be exercised to place the shoulder where it should be placed, 
and the precaution of not cutting too much must be observed always. 
Restoring Roots, Reduced to Gingival Border. In cases where 
all of the remaining natural crown has been, or must be, sacrificed PREPARATION OF TEETH AND ROOTS 
99 
to a point approximating the gingivae, the application of porcelain 
jacket crowns still may be made successfully. The preparation is 
simple. 
In such cases the entire basal end of the root first should be trimmed 
smooth and even to a point just within the free gingival margin. The 
canals may be enlarged sufficiently then to receive and accommodate a 
dowel and a restoration of the body of the natural tooth crown is made 
by casting. 
Fig. 62. 
This restoration is called an “internal cone” and is made in such man- 
ner as to form a shoulder by leaving the marginal edge of the entire 
periphery of the root freely exposed. (Fig. 62.) 
The internal cone restoration should be formed, or shaped, to follow 
the outlines of the original contour of the dentin, and the dowel, or dowels, 
should be an integral part of the restoration. It should be cast in gold, 
and when cast, finished and polished, it should be cemented to place on the 
root. 
Where the remaining natural root is fragile, or where caries may have 
reduced one surface below the normal gingival line, a somewhat different 
technic is demanded. In such cases, the cone should be extended to 
cover and protect the free margins of the natural root, except at the labial 
(or buccal) aspect and the shoulder should be made on the cone. When 
this method is used the porcelain jacket is in contact with the root end, at 
the labial (or buccal) margin but with the gold at the other three sides. 
A cone thus constructed protects the end of the root, but should not be 
high enough above the gingival margin to reduce the bulk of the porce- 
lain, and thus weaken the crown. 
Reduced roots are restored thus in a very simple and effective manner. 
One or more dowels may be used in accordance with the requirements of 
the root to be restored. 100 
CROWN AND BRIDGEWORK 
Preparation of Teeth Having Vital Pulps for Attachments 
for Bridgework. 
While full and partial shoulder crowns, perhaps, are the most generally 
useful methods of obtaining attachment to the crowns of teeth having 
vital pulps for the anchorage of bridgework, still, more simple methods 
involving a less complicated preparation are possible and indicated at 
times. 
Preparation for Inlays. 
Cast gold inlays frequently provide a useful method of obtaining at- 
tachments for bridgework and, particularly, in cases where the natural 
tooth crown already has been partially wrecked by caries, or where fillings 
are present. 
Where inlays are to be used for this purpose, the requirements of prep- 
aration demand that the remaining natural crown be prepared to insure 
every degree of strength in the attachment of the inlay, which resistance 
to stress in all directions, as well as permanency, will require. 
These requirements demand: 
First: That all thin, unsupported or weakened walls be trimmed down 
until adequate strength in the supporting tooth crown is assured. 
Second: That all cavity margins be extended to areas immune from 
contact with any part of the structure which is to be supported by the 
inlay. 
Third: The preparation must be made in such manner as to lock the 
inlay mechanically into place in its relation to the supporting tooth crown, 
and thus fortify it against the influences of stress in all directions. 
Unless resistance to stress in all directions is afforded and insured by 
the strength of the supporting tooth crown, and by the shape and form of 
cavity preparation, both combined, small holes for the accommodation of 
one or more short pins or dowels, should be provided. 
In teeth having vital pulps, the drilling of holes in the dentin for the 
accommodation of pins or dowels, of any size or length is both difficult 
and dangerous. Therefore, whenever this additional security is deemed 
necessary, every precaution must be taken to place the holes at points 
where pulp exposure, or pulp vitality, will not be endangered. 
In the preparation of the crowns of pulpless teeth, the pulp 
canal should be used, of course, for the accommodation of the dowel. 
Where a pulp canal may be used, one dowel, usually, is all that will be 
required. PREPARATION OF TEETH AND ROOTS 
101 
Preparation of Anterior Teeth. A type of preparation involving the 
incisal end and mesial and distal surfaces of upper anterior teeth is illus- 
trated in Fig. 63, and another variation involving a more extensive prepa- 
ration of the lingual surface, and only the mesial or distal surface together 
Fig. 63. 
Fig. 64. 
Fig. 65. 
Fig. 66. 
with a partial shoulder and a small pin placed in the lingual pit is illustrated 
in Fig. 64. 
These two forms of preparation are applicable, generally, to the six 
upper anterior teeth, and are useful when the preparation may be made in 
accordance with all the basic requirements. 
As a rule, the crowns of the six lower anterior teeth, and particularly 
of the incisors, are too small to accommodate such extensive preparation 
without endangering the vitality of the pulp. 
A simpler and less dangerous preparation, useful and generally appli- 
cable to the lower incisors, consists in placing two small holes parallel 
with each other, and vertical with the long axis of the tooth at a point 
on the lingual surface near the incisal end. (Fig. 65.) 
The holes should be about three millimeters in depth and of a size 
which will accommodate pins made of round iridio-platinum, or clasp- 
metal wire 18 to 20 gage. Wherever such holes may be placed success- 
fully, a more or less secure form of attachment may be made. 102 
CROWN AND BRIDGEWORK 
Preparation of Posterior Teeth. The preparation of cavities in the 
crowns of bicuspids and molars must include an observation of all the 
basic requirements. A series of typical cavity preparations is illustrated 
in Fig. 66, and the use of pins in conjunction with otherwise favorable 
cavity outlines is illustrated in Fig. 67. 
Fig. 67. 
Preparation for Combination Inlay and Partial Peripheral 
Band. 
A useful method of attachment to the crowns of posterior teeth involve 
the use of an inlay in combination with a partial peripheral band. Thu 
type of attachment is known as the McBpyle attachment. It is applicable 
to teeth having vital pulps, as well as to pulpless teeth. 
The use of a partial peripheral band in combination with an inlay affords 
a method of attachment possessing several advantageous features: 
First: Less extensive cavity preparation is required. 
Second: The peripheral band, being adapted to the largest circumfer- 
ence of the crown of the supporting tooth, requires but little preparation 
of the periphery. 
Third: The addition of the peripheral band adds materially to the 
strength of the attachment, even though the inlay is less extensive. 
Fourth: All margins of the attachment are carried beyond any possible 
contact with the bridgework structure. 
Fifth: Gingival contact and any resulting gingival irritation are 
avoided. 
Requirements. The requirements of preparation for this type of 
attachment, while demanding less extensive cavity preparation, demand 
that the inlay be seated well in and securely anchored to the natural tooth 
crown which is to support it, and that the peripheral band must be adapted 
closely to its supporting walls. And when two attachments are to be used 
in one fixture, the surfaces of the natural crowns which present toward 
each other must be made parallel the one with the other. The reduction of PREPARATION OF TEETH AND ROOTS 
103 
these surfaces, of course, is made at the expense of the enamel and may 
denude the dentin entirely, but when any appreciable reduction becomes 
necessary, it is restored with and by the peripheral band. 
Fig. 68. 
Fig. 69. 
Preparation for Simple Groove Attachments. 
Attachments, the use of which involves and requires but a minimum of 
destruction of the supporting natural tooth crown, may be designated as 
“groove” attachments. They also are known as Carmichael and Alexan- 
der attachments. This type of attachment may be used successfully when 
its application is confined to cuspids and bicuspids. 
The requirements of preparation involve the cutting of lateral and of 
incisal or occlusal retention grooves, and of shaping the mesial and distal 
walls to present parallel lines, and sacrificing the lingual or occlusal sur- 
faces to receive and accommodate the attachment. 
The cutting of the retention grooves is accomplished in the manner 
indicated for partial shoulder crowns, and, except that no shoulder is 
made, all other requirements are the same. 
The requirements of preparation, as applied to the crowns of cuspid 
teeth, are illustrated in Fig. 68, and as applied to bicuspids in Fig. 69. 
Preparation for Open-face Partial Crowns. 
Gold telescope crowns with a large portion of the labial surface cut 
away leaving only a narrow band presenting upon this surface, and cover- 
ing all other surfaces of the supporting tooth crown, are used sometimes 
as a means of obtaining attachment for bridgework. This type of at- 
tachment is known as an “open-face” crown, and, wherever indicated, 104 
CROWN AND BRIDGEWORK 
its application may be made without sacrificing or mutilating the natural 
tooth crown to any appreciable extent. 
If a maximum of conservation of the natural tooth crown is necessary, 
the application of this type of attachment is limited to cases where the 
natural tooth crown is of favorable conformation primarily. A primarily 
favorable shape, or a primarily favorable conformation will be found to 
limit a successful application to the cuspid teeth exclusively. 
Fig. 70. 
Fig. 71. 
The requirements simply demand that the mesial and distal surfaces 
of the supporting tooth crown be made parallel with each other (Fig. 70) 
and that the lingual surface he sacrificed to an extent sufficient to accom- 
modate the thickness of the gold which is to cover it. (Fig. 71.) 
Preparation of Roots for Dowel Crowns. 
Various types of all-porcelain dowel crowns are manufactured and 
may be purchased. Their adaptation to the supporting root is obtained by 
grinding the basal end of the crown to fit the root as closely as possible. PREPARATION OF TEETH AND ROOTS 
105 
A better and more permanent adaptation to the root, however, is obtained 
by making a coping of gold or platinum to meet more perfectly the 
requirements of adaptation, and building the crown upon this coping. 
Root-end Copings. In the construction of dowel crowns the term 
“coping” is used to designate the base of the crown, or that part of the 
crown which is adapted to, or engages with, the end of the root. The 
Fig. 72. 
Fig. 73- 
copings for dowel crowns are made with and without a peripheral band. 
The requirements of root preparation necessarily vary accordingly. 
Preparation for Dowel Crown with Full Peripheral Band. The 
requirements of root preparation for a dowel crown, with a full peripheral 
band as a part of the coping, include all requirements indicated for tele- 
scope crowns. They vary in one feature only: all of the remaining na- 
tural crown must be sacrificed to, or near to, the gingival line. 
Operative Procedure. In sacrificing the remaining portions of the 
natural crown, every effort to eliminate any and all unnecessary grinding, 
every effort to avoid shock and every effort to avoid the danger of 
fracturing the remaining root should be made. 106 
CROWN AND BRIDGEWORK 
Excising Remaining Natural Crowns of Incisors and Cuspids. 
In the incisors and cuspids, the removal of the remaining natural crown 
may be accomplished easily and quickly first by undermining the enamel 
by removing the supporting dentin with a good, sharp bur; then by cut- 
Fig. 74- 
Fig. 75. 
ting a groove into the labial and lingual surfaces at a point about one milli- 
meter from the gingivae (Fig. 72) the remaining crown may be excised 
easily without appreciable shock, and without danger of a root-wise frac- 
ture, by the careful use of the excising forceps. (Fig. 73.) 
The remaining natural crown never should be sacrificed primarily to a 
point even or flush with the gingiva, because a slight surplus facilitates 
both the removal of the remaining enamel, and the subsequent taking of 
the measurement and fitting of the band. 
Excising Remaining Natural Crowns of Bicuspids and Molars. 
The same procedure applies to the removal of the remaining natural 
crowns of bicuspids and molars, except that a good, sharp bur should be 
used to destroy the continuity of the buccal and lingual walls (Fig. 74) 
before using the excising forceps. 
Excising forceps are useful instruments in root preparation, but ex- 
treme care to prevent unnecessary shock, or fracturing of the remaining 
root beyond the desired point, should be observed always. 
Removal of Enamel. Wherever a peripheral band is to be used, all 
of the remaining enamel must be removed. The removal of the remaining 
enamel may be effected in the best and quickest manner by means of 
“enamel cleavers.” (Fig. 75.) PREPARATION OF TEETH AND ROOTS 
107 
Use of Enamel Cleavers. Enamel cleavers are useful only in pro- 
portion as they may be used properly. Several designs are obtainable. 
They are made with a strong, blunt end and a sharp, cutting edge. In 
their use the cutting edge must be held in its proper relation to the axial 
Fig. 76. 
Fig. 77 A, 
walls of the root, and a fulcrum must be established as a means of admit- 
ting the application of the force necessary to break the continuity of the 
remaining ledge of enamel and to detach it from its supporting structure. 
To establish a fulcrum, the handle of the instrument should be grasped 
firmly and the thumb rested steadily upon the incisal ends of the crowns 
of the adjacent teeth. (Fig. 76.) 
In the absence of adjacent teeth, a suitable rest may be made by mold- 
ing impression compound upon the soft tissues. If molded to a good 
adaptation and to proper proportions, and then chilled, in cold water, 
enamel cleavers may be used effectively and without discomfort to the 
patient. 
Shaping Periphery of Root. The requirements incident to the 
proper shaping of the periphery of the root are illustrated before shaping 108 
CROWN AND BRIDGEWORK 
and after shaping in Fig. 77 A. The correct position of the cutting point 
of a useful design of enamel cleaver, for first destroying the continuity 
of the remaining enamel, and the correct position for removing the enamel 
are shown in Fig. 77 B. 
Fig. 77 B. 
Fig. 78. 
A small crosscut fissure bur and short blunt files (Fig. 78.) are also 
useful in shaping the mesial and distal surfaces. 
Shaping Basal Surface of Root. The formation of the basal sur- 
face of the root is a procedure of considerable importance. 
Where a crown with a full peripheral band is to be used, the basal 
surface should not be shaped finally until after the enamel has been re- 
moved, the measurement obtained, and the band fitted. All of these pro- 
cedures are facilitated by allowing the root to project beyond the gingiva 
until they have been completed. When the final fitting of the peripheral 
band has been obtained, the root may be cut down to the desired point, 
and the proper shape given to its basal surface. 
Anterior Maxillary Roots. In anterior maxillary roots, the labial 
surface always must be cut down to a point at least approximating, and, 
in some instances, even slightly beneath the gingival line. This necessarily 
will cause the band to be very narrow along this surface, but the require- 
ments of esthetics preclude the use of a wide band. 
The esthetic requirements do not demand that the lingual surface be 
cut down to the same point, and, hence, this surface may be allowed to 
remain longer and to project beyond the gingival line. 
A projection of the root beyond the gingival line in the six anterior 
maxillary teeth ofifer a mechanical advantage. It provides more surface PREPARATION OF TEETH AND ROOTS 
109 
for telescoping contact between it and the band, and thus it strengthens 
the attachment of the artificial crown to the root by fortifying the attach- 
ment against the greatest stress which is imposed. By this means resistance 
to stress is increased mechanically. 
Fig. 79. 
Fig. 8o. 
Fig. 81. 
A combination of these esthetic and mechanical requirements in the 
formation of the basal surface will demand that the labial or buccal 
aspect be beveled as illustrated in Fig. 79, or that it assume a gradual in- 
clined plane as illustrated in Fig. 80. 
As any impingement is positively injurious to the health of the invest- 
ing tissues, the root never should be cut down beneath the gingiva at any 
point, except labially or buccally. This feature should be observed 
unvaryingly in the formation of the basal surface of all roots. 
The shape of the basal surface may be formed best with a flat-edge, 
true-running carborundum stone. (Fig. 81.) The stone should always be 
kept wet while cutting. When reduced to a point approximating the gingi- 
val curvature, with a stone, in this manner, the labial or buccal edge may 
then be carried to a point slightly within the free gingival margin by the 110 
CROWN AND BRIDGEWORK 
use of the Ottolengui root facer. (Fig. 82.) In choosing the root facer one 
should be selected the diameter of which is no greater than the mesiodistal 
diameter of the root end and extreme care must be exercised always to 
prevent any undue laceration of the investing tissues. 
Fig. 82. 
Fig. 83 A. 
Fig. 83 B. 
Mandibular Anterior, and Bicuspid and Molar Roots. In mandibu- 
lar anterior teeth, and in bicuspids and molars, both maxillary and man- 
dibular, the basal end should be cut down and shaped to follow the gingi- 
val curvature closely at all points. Adequate resistance to stress is offered, 
and the health of the investing tissues is conserved thereby. 
Preparation for Dowel Crowns Without Peripheral Band. 
In the preparation of roots for dowel crowns without a peripheral 
band, the requirements are the same in every respect and in every detail, 
except that the removal of the enamel and any peripheral preparation what- 
ever is entirely unnecessary. And for the reason that no peripheral prepa- PREPARATION OF TEETH AND ROOTS 
111 
ration is required and that the normal condition of the investing tissues is 
conserved, therefore, the advantages offered by this type of dowel crown 
are evident. Typical root preparation is illustrated in Fig. 83 A. Another 
type of preparation involves a four-sided bevel (Fig. 83 B) and is particu- 
larly useful where the coping is made by casting. 
Preparation of Root Canal. The dowel plays an important role 
in the construction of all types of dowel crowns. A knowledge of the re- 
Fig. 84. 
quirements of a dowel, therefore, and of the preparation of root canals 
for the reception of dowels, is essential. 
Requirements of a Dowel. All the strength obtainable in the attach- 
ment of a dowel crown to its supporting root is afforded by the dowel it- 
self. 
The mounting medium protects the root, and the crown coping protects 
the mounting medium—just in proportion as the adaptation is good—but 
the crown coping affords but little resistance to stress. It adds but little 
strength to the attachment, therefore. It is evident, then that a dowel must 
be adequate to all requirements of strength. 
To be adequate to the requirements of strength, it must be proportion- 
ate in size with the size of the root. It must extend into the root to a dis- 
tance equal to the length of the crown (Fig. 84) and it must be composed 
of an alloy possessing inherent strength. 
Where these requirements are met a single dowel, even in multi- 
rooted teeth, will adequately supply secure and permanent mechanical 
fixation. But in multi-rooted teeth it may not be possible always to 
prepare a single canal to receive a single dowel, meeting these require- 
ments in size and length. In such instances two dowels, or, in rare cases, 
even three dowels may be needed. 
The supporting root never should be weakened unnecessarily by the 
preparation of its canal or canals to accommodate a dowel or dowels. 112 
CROWN AND BRIDGEWORK 
In multi-rooted teeth, if the largest canal may not be prepared properly 
to accommodate a dowel subscribing to these requirements, then smaller 
and shorter dowels should be used. 
In preparing the canal to receive and accommodate the dowel, tapered 
twist drills, or round burs of a size just slightly larger than the diameter 
of the dowel, should be used. 
Any necessary enlargement of the canal always should be made in the 
direction of the lingual surface. This provision causes the surplus end of 
the dowel which is to project through the coping to be carried well toward 
the lingual aspect of the root, thus providing for the subsequent accom- 
modation of the porcelain tooth, or facing. 
Unless this precaution is taken, the subsequent proper alinement of 
porcelain tooth, or facing, is to be obtained only by sacrificing the sur- 
plus end of the dowel. And, if this surplus end is sacrificed to too great an 
extent, the strength of the relationship between the body of the crown and 
its supporting dowel is diminished accordingly. 
Whether the crown be a combination of metal coping and porcelain 
tooth, or facing, or whether it be made entirely of porcelain; or whether 
the dowel be separate and unattached to either root or crown previous to 
mounting, or whether it be made an integral part of the crown before 
mounting, the final attachment between crown and dowel always must 
be made in such manner as to insure adequate strength. 
The procedure should be followed with extreme care at all times and 
particularly in first biscuspid, molar and all constricted roots, and every 
effort must be made to avoid drilling through the end, or perforating the 
walls of the root. 
Shape of Dowel. The dowel may be round, triangular or square, 
and, like the root which is to receive it, should be tapering throughout 
its entire length. Its largest diameter should be at the immediate line of 
junction between crown and root where the greatest strength is required. 
It may be threaded, or roughened with a file, as a means of insuring a 
more secure attachment of the mounting medium. 
Alloys for Dowels. Special alloys, possessing the physical properties 
of inherent strength, toughness and sufficiently high fusibility should be 
used for dowels. 
Iridio-platinum or high-fusing, round clasp-metal wire, not larger than 
14 gage, nor smaller than 16 gage properly shaped to meet the require- 
ments of the individual case is generally used for dowels. 
Alloys of nickel are used, also, but dowels made of alloys containing 
nickel, or any of the base metals, do not alloy well with gold solders or PREPARATION OF TEETH AND ROOTS 
113 
casting alloys and are effected to a greater or less extent by the acid bath, 
and by the cements used in mounting. Economy, therefore, is the only 
advantage obtained from their use. 
Treatment of Perforated Roots. 
The roots of teeth, otherwise good and healthy, may present sometimes 
with a perforation through their peripheral walls at some point. The 
perforation may be caused by accident or it may be the result of caries. 
If it is the result of accident, it usually presents through the side of the 
root somewhere between the gingiva and the apex. Such perforations are 
usually made during the procedure incident to enlarging the canal for the 
accommodation of the dowel. 
If the perforation is the result of caries, it usually presents through the 
walls of the pulp chamber and in between the bifurcation of the roots in 
multi-rooted teeth. 
In either class of cases, a successful reparative procedure is difficult 
and doubtful. Hence, perforated roots are usually doomed to early loss. 
In cases where the conservation of the root is important, however, and 
where the age of the patient and the general health of the root and of its 
investing tissues is favorable, an effort to repair the perforation is war- 
rantable and may be attempted. 
A successful reparative procedure demands that such perforation be 
filled under aseptic conditions and hermetically sealed with some non-irri- 
tating and insoluble substance. Gold foil, tin foil and gutta-percha are 
used for the purpose. If any of these is made previously into a cone, 
or formed into a shape approximating the size of the perforation, and then 
gently forced into the perforation until it is filled completely, and more or 
less compactly, and without forcing the material beyond the external walls 
of the perforation to any appreciable extent, and the filling is then covered 
over with cement, the procedure may be rewarded with success. At least 
the possibilities justify the effort. 
Where the perforation presents in roots the canals of which have not 
been filled previously, the perforation should be filled and the protecting 
layer of cement allowed to become crystallized thoroughly before any ef- 
fort is made to fill the canal. Otherwise, a surplus of root-filling material 
is certain to be forced through the perforation. 
This procedure is usually facilitated by placing root-canal broaches, or 
wires, into the canals to the full length and size of the canals, first, and 
filling the perforation while the broaches, or wires, are in place, after 
which they may be removed gently and the canals filled at a subsequent 
time. 114 
CROWN AND BRIDGEWORK 
While gold foil and gutta-percha may be used successfully, the use of 
tin foil offers an additional advantage over each. If the perforation is 
filled successfully with tin foil, under the influence of temperature and 
moisture, the oxid of tin is formed and a more hermetical sealing is af- 
forded thereby. 
Treatment of Fractured Roots. 
The roots of teeth are fractured frequently, either as a result of acci- 
dent or from the influence of stress. A fractured root often is a hopeless 
root and the proper treatment consists usually in its immediate removal. 
There may be instances, however, where the nature of the fracture, 
the age of the patient, the importance of the tooth, the desirability of its 
retention and the general health of the investing tissues, all combined, 
would indicate and justify some effort toward the conservation of frac- 
tured roots. 
Anterior Roots. A very large proportion of the fractured roots 
in which any great effort toward their conservation would be at all justifi- 
able would be confined to the anterior teeth. 
Fractures of the roots of anterior teeth usually present labiolingually, 
with the labial portion broken away from the body of the root. Where 
the fractured portion does not extend any great distance beyond the alve- 
olar border it is best to remove the fractured portion, compress the 
soft tissues with gutta-percha, or temporary stopping, until the end of 
the remaining root is exposed freely, and then effect the restoration of 
the lost section with and as a part of the artificial crown. This may be 
accomplished best by means of the indirect method. Where the restoration 
is not too extensive good results may result. 
Where the fracture extends beyond the alveolar border to any great 
extent, any mechanical treatment is usually hopeless, and the removal of 
the entire root becomes necessary. 
If mechanical treatment may seem to offer any hope whatever, it may 
be obtained in the best manner, by first thoroughly cleansing and drying 
the fractured parts with alcohol and hot air, and, second, flowing thin, 
well-mixed cement into the joint. The fractured root then may be brought 
into close apposition by twisting strong silver suture wire, or copper meas- 
urement wire, tight around the entire circumference, and permitting the 
wire to remain until the cement has crystallized. It then may be removed 
and a narrow band made of platinum, or gold, fitted carefully to the per- 
iphery of the root and cemented permanently. 
By this means a secure fixation of the fractured section may obtain, PREPARATION OF TEETH AND ROOTS 
115 
after which an artificial crown may be constructed, the adaptation of the 
crown being made over the band previously cemented to the root. 
In exceedingly large roots where the line of fracture leaves each seg- 
ment in nearly equal proportions, what is known as an intradental band 
may be used instead of a peripheral band. 
In the use of an intradental band, the same procedure indicated for 
using a peripheral band up to and including the twisting of the temporary 
Fig. 85. 
Fig. 86. 
wire is followed. A circular groove of adequate but safe depth is then 
trephined into both segments of the root (Fig. 85) and an intradental 
band made of gold, or platinum, then forced to place within the groove. 
A very simple set of trephines and exact measurements are used and 
this procedure affords a secure fixation of the fractured segment within 
the periphery of the root. The fixation thus obtained may be fortified fur- 
ther and strengthened by the application of an artificial crown having a 
peripheral band. 
Posterior Roots. The same conditions and the same possibilities and 
limitations apply to the mechanical treatment of the fractured roots of 
posterior teeth. But, since conservation of the roots is not so important 
in the posterior teeth as it is in anterior teeth, effort in this direction is 
justifiable in a much smaller proportion of cases. 
Instead of using an intradental band, which is not applicable to pos- 
terior roots to the same extent, a similar means of mechanical fixation may 116 
CROWN AND BRIDGEWORK 
be obtained by undercutting and dovetailing each segment of the fractured 
root. 
This should be done after temporarily sustaining their relation by 
means of a tightly twisted wire, or with a temporary band fitted closely 
to the periphery. This counter dovetailed preparation of each segment 
forms a cavity which then may be filled with amalgam and which, when the 
amalgam has crystallized, will insure a more or less secure fixation (Fig. 
86) after which a permanent crown may be made. 
Free Exposure of Basal Surface. 
In the preparation of all roots the natural crowns of which are sacri- 
ficed, necessarily, to the gingiva and at all times during the construction 
of dowel crowns of any type, the basal surface should be exposed freely 
and should be kept exposed freely. The free exposure of the basal surface 
of the root facilitates its proper preparation, facilitates the requirements 
of adaptation of the crown and lessens the usual attending discomfort to 
a very appreciable extent. 
These advantages are important and they are to be obtained easily by 
packing gutta-percha, or temporary stopping, firmly over the basal surface 
of the root after the remaining natural crown has been sacrificed, and 
previous to making any attempt to effect the adaptation of the coping and 
insuring its secure retention. 
And, once the root has been prepared, the patient never should be 
dismissed for any length of time, beyond a few hours, without taking 
this precaution. The mounting of some form of temporary crown will 
answer the same purpose. 
Aside from the advantages arising from a free exposure of the basal 
surface of the root and considering the simplicity with which a temporary 
crown may be made, as well as the embarrassment and disfigurement oc- 
casioned by the absence of a missing anterior tooth—a patient for whom 
a permanent restoration is being made never should be dismissed without 
some type of temporary crown upon the root. CHAPTER X. 
GOLD TELESCOPE CROWNS. 
The gold telescope crown with peripheral band, commonly designated 
as the “shell” crown, was one of the early achievements in the restoration 
of the crowns of natural teeth. 
As a means of restoration as a single unit, and as a means of affording 
attachment for bridge work, this type of crown has served the purpose so 
long and so well that probably a greater number of teeth have been saved 
and restored to usefulness by it than by any other. 
When indicated and when constructed properly and well adapted, the 
gold telescope crown with a band is a useful means of crown restoration. 
Being a useful means of restoration, however, does not imply that it is 
applicable to all teeth at all times. 
The adaptability of gold, the indestructibility of a full gold crown and 
the opportunities for restoring teeth and roots to usefulness, in a manner 
more or less simple, efficient and permanent, presented advantages which 
were rapidly recognized. And the recognition was followed quickly by 
abuse. But the abuse was such as always follows indiscriminate application 
and failure to observe requirements. Indiscriminate application and fail- 
ure to observe requirements always must end disastrously; but this should 
not necessarily condemn the method or principle involved. 
Indications. In restoring the crowns of teeth, and in obtaining at- 
tachment for bridgework, no one method of procedure is applicable uni- 
versally, and adaptability and indestructibility are not the only require- 
ments. 
The full gold telescope crown possesses several advantageous features 
and has a place of usefulness, but that does not often embrace application 
to the restoration of teeth which are within the range of vision. 
The restoration of the crowns of teeth, the replacement of missing 
teeth, the practice of crown and bridgework all are associated with 
artistic possibilities. To imitate or to simulate nature so closely that 
detection is difficult, if not impossible, is a fascination of art, but an in- 
harmonious and unnecessary display of gold is an offense to art and violates 
all traditions of art. 
The use of full gold crowns, or the unnecessary display of gold, there- 
117 118 
CROWN AND BRIDGEWORK 
fore, is contraindicated in the restoration of the teeth within the area 
of visibility. 
Hence, the range of application and the field of usefulness of gold 
crowns should begin with the molars and should end with the second 
bicuspids. In rare instances, where the “bite” is abnormally close, where 
the restoration must be exceedingly short and where the requirements of 
esthetics must give place to the requirements of indestructibility, the 
general limitations may be extended to include the first bicuspids: and this 
will be more often true in the lower jaw. In such cases and under such 
conditions the application of gold crowns to first bicuspids may be 
indicated as the best and safest procedure. 
Anterior to first bicuspids, however, the use of a gold crown, or the 
unnecessary display of gold, is an offense to the possibilities of dental 
art, and to the cultural refinement of the patient. Or, it is an admission 
of indifference, or an evidence of charlatanism on the part of the dentist. 
For these reasons the application and the methods of construction 
of anterior gold crowns will receive no further consideration. 
Requirements. In addition to the abuse following indiscriminate 
application, the evils of faulty adaptation have much reduced the possible 
usefulness of the gold telescope crown. This type of crown, or any 
type of crown involving a telescoping peripheral band, is susceptible 
to abuse in proportion as the band does or does not fit its supporting 
tooth or root. Peripheral bands may cover a multitude of sins, and, 
unquestionably, are often a menace to the health and vitality of the in- 
vesting tissues unless the requirements of adaptation are observed closely. 
If the band is too large, or if it is forced too far beneath the gingival 
border, both of which are common practices, irritation of the investing 
tissues must result. Radiographic evidence proves conclusively that a 
large proportion of gold telescope crowns are thus badly adapted. The 
use of manufactured or ready-made crowns, or of “seamless” crowns 
made by dental laboratories, is responsible, largely, for an indifference to 
the necessity of proper adaptation. But if the requirements of adaptation 
are observed closely, a peripheral band need not necessarily be a source 
of irritation. 
Any tooth or root which is deserving of restoration by means of an 
artificial crown of any type is deserving of a restoration which fits. And 
any tooth, or root, which is capable of affording attachment for bridge- 
work is deserving of an attachment which will not do irreparable injury. 
The successful application of full telescope crowns with a peripheral 
band, therefore, will depend upon an observation of the requirements of GOLD TELESCOPE CROWNS 
119 
adaptation; and the degree of success will be proportionate to the degree 
of accuracy obtained. 
Full telescope crowns, with a peripheral band, must be sufficiently 
thick and heavy when finished to insure adequate strength and perma- 
nency, and must be made of a gold alloy sufficiently high in karat to with- 
stand the chemical action of the oral secretions. 
Telescoping portion. The edge of the band which telescopes the end 
of the root should fit closely around the entire circumference; pass a 
short, but uniform, distance beneath the gingival border, and possess a 
smooth, rounding edge, so as to offer no possible irritating influence to 
the investing tissues. The band itself then should be contoured to typical 
form; it should restore the points of contact, and preserve a proportionate 
and symmetrical alinement with the adjacent teeth. 
Occlusal surface. The cusp formation of the occlusal surface should 
mimic or approach a typical reproduction of the particular tooth, restore 
functional occlusion, and offer no interference to the various excursions 
of the mandible in the movements of mastication. 
The cusps also should be deep and sharp enough to be effective in 
mastication, and of sufficient thickness to withstand constant and con- 
tinued attrition. The presentation of a more or less smooth and uncon- 
toured masticating surface precludes the proper mastication of food, and 
thus diminishes the efficiency. 
Methods of Construction. The construction of full telescope crowns 
with a peripheral band involves two different methods of procedure. One 
consists, first, in making and fitting the band, and subsequently forming 
and attaching the cusps, or the occlusal surface, to it. This method is 
known as the sectional method. The other consists in making the entire 
crown in one piece and is known as the seamless method. 
Sectional Method. 
In the sectional method the band and cusps are made separately. This 
method affords every advantage offered by the seamless method, and em- 
braces a more simplified, technical procedure. It affords opportunity for 
greater accuracy of adaptation and even better reproduction of contour. 
It requires less time and permits the use of a heavier gage of gold 
throughout the construction. These important advantages cause it to be 
readily accepted as the most universally useful and successful method of 
construction. 
The joint made by the union of band and cusps offers no objectionable 
feature and in no way interferes with artistic possibilities, provided that 
the edges are closely approximated, and that the union is made with a 120 
CROWN AND BRIDGEWORK 
solder resembling closely the color of the crown gold, and sufficiently 
high in karat to withstand the chemical action of the secretions without 
subsequent discoloration. 
Making the Band. In the procedure incident to the construction of 
crowns having a peripheral band, the details to be observed embrace first, 
a true measurement of the circumference of the root and second, making 
Fig. 87. 
Fig. 88. 
the band. A band of accurate dimensions can be secured only from an 
accurate measurement. 
Measurement: Small copper wire, about No. 32, is generally used. 
A suitable length of wire should be cut, made in circular form, somewhat 
larger than the root, and the ends securely attached to a small dentimeter. 
While many varieties of dentimeters may be used, a jewelers’ small, slide 
pin-vise affords the quickest, easiest and most secure adjustment, with 
less danger of cutting the wire when twisting. 
The loop of wire should be carried to place over the tooth, or root, 
passed just freely beneath the gingival border and twisted taut, being 
careful in the meantime to conform and adapt it to all concavities. 
(Fig. 87.) 
Where the root is short, or cut down to the gingival line, it may 
become necessary to hold it in position with a suitable instrument, in 
order to prevent any displacement of the wire while twisting. Usually 
it is most convenient to twist from the buccal surface; but on second and 
third molars, it sometimes may be found more convenient to twist from 
the lingual surface. GOLD TELESCOPE CROWNS 
121 
After thus securing the correct measurement of the circumference 
of the tooth, or root, the wire should be cut in two at a point farthest 
away from the twisted end, and each end of the former loop carefully 
straightened out until smooth, continuous and at right angles with the 
dentimeter. (Fig. 88.) 
When two or more crowns are being constructed at the same time, 
and especially when the roots are nearly of the same size, each measure- 
Fig. 89. 
ment should be given some characteristic bend or twist, in order to 
distinguish one from the other. By this means any confusion in the 
subsequent fitting of the bands may be avoided. 
The strength possessed by the finished crown, in its attachment to 
the root, increases in proportion to the thickness of the gold plate of 
which the band is made. As gold stretches easily, and since its thickness 
is diminished necessarily to a certain degree by subsequent finishing and 
polishing, plate gold, not thinner than 28 gage nor less than 22 karat 
in fineness, should always be used for bands. As thin as 29, or even 30 
gage gold plate may be used, but 28 gage retains its shape better and 
admits of greater freedom in finishing. 
Width : The desired width of the band should be noted with the eye, 
or, if necessary, measured with a piece of cardboard trimmed to the 
correct width; or with a small pair of calipers. (Fig. 89.) 
Length: The band should always be cut with the grain of the metal, 
and the cervical edge, or that edge which is to be fitted to the tooth, or 
root, should be cut to approximate the exact length of the measurement 
wire. Any great variation between the circumference of the root and 
the dimensions of the space to be filled by the crown may require that 
one edge of the band be cut on such an angle as to make a difference 122 
CROWN AND BRIDGEWORK 
between the circumference of its cervical and occlusal edges when soldered. 
(Fig. 90.) 
Perfectly straight edges usually will afford sufficient opportunity for 
obtaining the necessary contouring of the occlusal edge of the band, but 
Fig. go. 
Fig. 91 
frequently it is desirable and sometimes even necessary to have this edge 
of slightly larger proportions, especially in bicuspids, in order to meet 
more perfectly the requirements of contact and alinement. 
Where the circumference of the root is greater than the space to be 
filled—a condition which is usually caused by the migration of the adja- 
cent teeth—the converse may be indicated in order to secure and preserve 
the buccal and lingual alinement of the occlusal surfaces. In such in- 
stances the edges should be cut straight to facilitate the adaptation to the 
root. The circumference of the occlusal edge may then be reduced 
adequately as illustrated in Fig. 91. 
Cone-shaped Bands. Where the maximum circumference of the root, 
properly prepared, is much less than that of the space which the crown 
must fill, or where an exaggerated contour is required to meet the demands 
of contact and alinement, a cone-shaped band may be made by cutting 
the gold on a curve, as indicated in Fig. 92. 
Soldering the Band. When the band has been cut properly, it should 
be annealed by heating to a cherry-red and plunging into alcohol or water. GOLD TELESCOPE CROWNS 
123 
The edges, then, should be made true and smooth, so as to approximate 
evenly when brought into contact, and the band made into circular form. 
Contact between the edges is essential to insure accurate size, and to 
facilitate soldering. This contact may be sustained by overlapping the 
Fig. 92. 
Fig. 93. 
Fig. 94. 
edges first (Fig. 93), and then bringing them back into direct contact. 
This procedure condenses the molecules sufficiently to overcome expan- 
sion, which, otherwise, would cause a separation when heated. It is 
preferable to wiring the outside circumference of the bands, because the 
solder frequently penetrates the joint and attaches the wire to the gold, 
necessitating its being ground off afterwards. 
When the edges have been approximated thus, the band should be 
grasped with fine-pointed pliers at a point as remote from the joint as 
possible, so that the pliers absorb but little heat. (Fig. 94.) Flux should 
be applied, carried to the flame and fused. A very small piece of solder 
should then be fluxed and placed immediately over the joint. 
In soldering, the band should be held in the flame in such manner as 
to heat both edges uniformly. If either edge should receive a greater 
degree of heat than the other, the solder would become attached to it, 124 
CROWN AND BRIDGEWORK 
and the addition of a second piece made necessary. The use of more 
solder than is required to make the joint is objectionable because of addi- 
tional stiffness thus imparted to the band. 
To prevent subsequent refusing, and to admit of finish- 
ing with solder of as high karat as possible, all bands should 
be soldered with 22 karat solder. Lower than 20 karat 
never should be used. 
For convenience and comfort, the pliers used for solder- 
ing bands should possess a long handle and thin, taper- 
ing points. (Fig. 95.) The soldering may be accomplished 
easily and quickly by holding the band over an ordinary 
Bunsen flame. 
Fitting. Fitting the band to the tooth, or root, may be 
made with facility and accuracy and without great dis- 
comfort if it is shaped previously to conform to the root 
and its surrounding tissues before any attempt is made to 
adjust it. The requirements which should be observed in 
this connection, in detail, are as follows: 
First: The band should be conformed to the general 
shape and outline of the root before any attempt at fitting 
is made. 
Second: The edge of the band which is to pass slightly 
within the gingival border must be trimmed to follow 
closely the outlines of the gingival curvature, in order that 
this edge will come in contact with the investing tissues 
evenly and uniformly at all points, before the final pressure 
is applied. 
Third: The edge must be round and smooth in order 
that no unnecessary irritation will be offered. 
Fourth: For convenience and to avoid any confusion 
in adjusting and readjusting bands, and because the usual 
convexity of roots at this point facilitates the adaptation of 
the stiffened portion of the band, and because of placing 
the soldered joint where it will be least conspicuous in case 
of subsequent discoloration, as well as being most easily 
accessible for reinforcement in the assemblage of bridge- 
work, the joint should always be placed at the center of 
the lingual surface of the root. 
To overlook or neglect any of these essential features 
adds to the difficulties incident to fitting bands and to the 
degree of discomfort occasioned by the procedure. In ob- 
Fig. 95. GOLD TELESCOPE CROWNS 
125 
serving these features the band should be placed gently over the tooth, or 
root, first, and then shaped with pliers until it is made to conform to the 
general outline, and to any existing concavities or inequalities. 
Gingival Edge. The gingival edge then should be trimmed care- 
fully with curved pointed shears (Fig. 96) until it meets the gingival line 
evenly at all points. Then it should be rounded nicely from the outer 
surface with a fine half-round file until blunt and smooth. The possi- 
bility of irritation is thus overcome without any appreciable loss of thick- 
ness of gold. 
Fig. 96. 
When these requirements have been met the band should be placed 
upon the tooth or root, and gently pressed to place until the edge passes 
just beneath the gingiva. For this purpose, a small piece of wood of 
convenient size, with flat, smooth surfaces, is most useful. If used 
properly, a small piece of wood greatly facilitates the procedure and over- 
comes any necessity for using more force, or for driving the band to place. 
This latter procedure is entirely unnecessary, even brutal, and should 
always be avoided. 
In instances where a normal, healthy recession of the gingiva may 
have exposed the root beyond the normal outlines at some point, which 
condition is found frequently, a separate extension of the band may be 
indicated in preference to trimming it upon all other surfaces sufficiently 
to admit of contact with the gingiva at this particular point. 
This may be accomplished : First, by fitting the band accurately without 
regard to this extension, after which a small piece of pure gold plate 
may be tacked first, with solder, to the outer surface of the band, and 
then trimmed and burnished until the exposed portion of the root is 
covered. When the desired outline and adaptation have been obtained it 
may be sustained permanently by reenforcing the extension with a high 
grade solder. 126 
CROWN AND BRIDGEWORK 
When the cervical adaptation of the band has been completed, the 
occlusal edge should be trimmed to afford accommodation for the adjust- 
ment of cusps of uniform and sufficient thickness. 
Occlusal Edge. In trimming the occlusal edge of the band, two 
methods of procedure are followed. The first and preferable procedure 
consists in allowing the full band to remain as long as possible and trim- 
ming its entire occlusal edge until it is just clear of contact with the oppos- 
ing natural teeth. (Fig. 97.) 
Fig. 97. 
Fig. 98. 
This procedure brings the immediate joint between band and cusps 
at the occlusal angle and provision for the thickness of the cusps must 
be made, of course, from the inside, and at the expense of the occlusal 
end of the supporting tooth. 
If such provision is made, this is the logical point for the joint. 
Placing the joint at this point affords every opportunity for the artistic 
reproduction of tooth form by contouring, and carries the line of solder 
to a point where subsequent discoloration will not be in evidence. 
Contouring. The entire artistic effect of the finished crown, as well 
as an observation of the requirements of contact and alinement depend 
in a great measure upon the form and shape given to the occlusal edge 
of the band. 
By contouring is meant the reproduction of the natural form and 
outline of the tooth. Artistic results are made possible only by a thor- 
ough knowledge of the surface angles and general form of the crowns of GOLD TELESCOPE CROWNS 
127 
natural teeth, the outlines of which should be reproduced in this edge of 
the band. This may be done, irrespective of the necessary form assumed 
by the cervical edge, and without change of it. 
Fig. 99. 
Fig. ioi. 
Fig. 100. 
For contouring purposes, various styles and designs of pliers are 
used, but only a few are needed. All of the artistic results necessary 
may be accomplished easily with two pairs of pliers. These are known 
as “hawk-bill” and “straight-nose” pliers. The hawk-bill pliers are 
particularly adapted to contouring the buccal and lingual surfaces of 
bands where some expansion of the central portion is desired. (Fig. 98.) 
Straight-nose pliers which have beaks which come together closely and 128 
CROWN AND BRIDGEWORK 
which possess rounded edges (Fig. 99) are useful in producing angles 
and ridges and in contracting the edges as illustrated in Fig. 100. 
The full possibilities of contouring as applied to bicuspid and molar 
bands trimmed to the occlusal angle is illustrated in Fig. 101. 
The other and second method of procedure which probably is used 
more generally, consists in trimming the occlusal edge of the band to 
allow for the full thickness of the cusps. This method places the joint 
Fig. 102. 
between band and cusps at a point where any discoloration of the solder 
will be visible, but, otherwise, affords the same artistic possibilities. 
The typical results possible in this method of procedure and which 
are obtained from a knowledge of the form and outlines of the teeth, 
and from a skilful manipulation of the pliers, are illustrated before and 
after contouring the band in Fig. 102. 
In instances where the size of the supporting tooth, or root, after 
being prepared properly, is larger than the dimensions of the occlusal sur- 
faces of the adjacent natural crowns, it may become necessary to reduce 
the circumference of the occlusal edge of the band to secure a symmetrical 
alinement. 
This reduction may be accomplished easily by cutting numerous slits GOLD TELESCOPE CROWNS 
129 
around the approximal and lingual surfaces of the occlusal edge and then 
drawing in the flaps thus made, overlapping them until the circumference 
is reduced sufficiently, as illustrated previously in Fig. 91. These slits 
will be filled with solder and a smooth, uninterrupted surface will present. 
When the desired requirements of contour of the band have been ob- 
tained by either method, the details incident to the production of the 
cusps or the formation of the occlusal surface follows. 
Forming the Cusps. 
Several different methods of procedure are followed in the formation 
of the occlusal surfaces. These methods include swaging and casting and 
are so numerous as to make a selection of the one universally best method 
practically impossible. 
The simplest and most accurate occlusal surfaces are undoubtedly 
obtained by transferring the band from the mouth to the laboratory by 
means of an impression and cast. 
Impressions and Casts. When the details of occlusal surface forma- 
tion are to be transferred to the laboratory, the interior of the band, in 
position on the supporting tooth or root, should be filled first flush with 
its edge with wax, or temporary stopping. This precaution facilitates 
the taking of the bite, and its subsequent adjustment to the cast. 
Bite. The bite always should be taken previous to taking the im- 
pression, because the imprint of the band is necessary to admit of its 
adjustment to the cast having the band in place. Ordinary pink base- 
plate wax is preferable for this purpose, because of the facility with which 
a good imprint of the teeth may be secured, and because of its more easy 
and accurate adjustment to the cast. 
In obtaining the bite, sufficient wax should be used to secure the im- 
print of several teeth on each side of the crown. And, in the procedure, 
it should be ascertained definitely that the teeth are in centric occlusion. 
When a proper relationship is obtained the patient then should be in- 
structed to close firmly and to press the wax against the lingual surfaces 
of the teeth with the tongue. By compressing it closely to the buccal 
surfaces with the fingers at the same time, a well-defined bite is obtained 
readily. 
Impression. The impression always should be taken with plaster 
and, corresponding with the bite, should include several teeth on each 
side of the crown. This is necessary in order to prove the bite and to 
sustain the correct relationship when mounted upon the articulator. 130 
CROWN AND BRIDGEWORK 
The use of plaster for the impression is essential because of the diffi- 
culty of, and the uncertainty in, adjusting the band to its accurate position 
in the impression when any material is used which draws in removing. 
This very important procedure may be accomplished with a degree of 
absolute certainty when plaster is used. 
Fig. 103. 
Because of the natural form of the crowns of teeth it will be necessary 
to fracture the plaster impression in removing it. Accuracy is insured 
by fracturing. The fractured pieces must be reclaimed, however, and 
must be large enough to be replaced accurately and the replacement 
sustained securely with hard wax. 
When the parts are replaced accurately and their relationship sus- 
tained securely, the impression should be varnished, filled, separated, the 
bite adjusted, and then mounted securely upon the articulator. 
Originally the occlusal surface of gold crowns was formed by solder- 
ing a flat surface of gold plate to the occlusal edge of the band and the 
cusps were constructed with small globules of scrap gold, or with pieces 
of triangular irridio-platinum, or clasp-metal wire, attached with solder. 
The desired form was obtained subsequently by grinding. 
Die and Die-plate Methods. 
While many of these crude, inaccurate and inartistic efforts were suc- 
cessful from the standpoint of usefulness, a desire for more artistic results 
led to the introduction of dies and the process of swaging. GOLD TELESCOPE CROWNS 
131 
Individual Dies. The first efforts in the direction of dies were made 
in the form of individual dies obtained from extracted teeth Suitable 
teeth were selected and mounted in a plaster base, trimmed to favorable 
shape. A mold was made in sand and a casting made of zinc. (Fig. 103.) 
Fig. 104. 
Plate gold was swaged to conform to the outlines of the natural cusps 
by driving the zinc die into a smooth surface of lead, or tin, or an old, dis- 
carded counter-die. This method was productive of such a degree of 
improvement over the former procedure as to cause the manufacturers 
to make dies of brass. They were made in sets including various sizes 
and forms. 
Die-plates. Because of the immediate necessity for a suitable counter- 
die to take the place of the block of lead or tin, the introduction of the 
die-plate followed. 
Die-plates comprise various numbers of cusp-molds grouped in a 
brass or steel casting. (Fig. 104.) In their use, swaging is accom- 
plished easily and quickly by driving a disk of plate gold, of suitable size 
and thickness, into the mold selected, with an ingot of lead or of an alloy 
of lead and tin. Ordinary buckshot, size No. 1 or No. 2, answer the 
purpose nicely. Die-plates made of steel may be used thus, or may be 
used to form solid cusps by driving an ingot of gold directly into the 
mold selected. 132 
CROWN AND BRIDGEWORK 
These die-plates are to-day in common use. Their usefulness and their 
range of application increases in proportion to the number and variety 
of cusp-forms embraced, and their limitations decrease accordingly. 
Use of Die-Plates. In the use of die-plates, the mold should be 
selected which best represents the individual tooth to be crowned, and 
which approximates the size of the band. The requirements of occlusion 
must be observed in the fitting and adjustment of the swaged cusp-form 
to the band. This can be done only after swaging. 
Adjusting Swaged Cusps to Casts. Swaged cusp formed by any 
die-plate system or method can be fitted and adjusted best to the require- 
ments of occlusion by obtaining the relationship with casts mounted upon 
the articulator. Opportunity is thus afforded for trimming the band, or 
the swaged cusps, or both, until their approximation, together with a 
favorable occlusion, obtains. By this means accuracy can be noted upon 
the lingual, as well as upon the buccal surfaces. 
The requirements of occlusion may be obtained and perfected by 
depressing or expanding the cusps, using a blunt instrument or a piece of 
hard wood for the purpose. When the requirements have been met, an 
effort should be made to approximate closely the edge of the swaged cusps 
to the band. A close approximation may be made by bending the edge of 
one or the other with pliers. Care must be exercised not to distort the 
shape of the band, nor destroy its contact and alinement. 
As a final means of perfectly meeting the requirements of occlusion, 
and of proving that accuracy obtains, it is good practice to attach band 
and cusps, first, with a minimum of solder, and then place the crown 
in position on its supporting tooth or root, in the mouth. 
Owing to the temporary thinness of the cusps at this time, they may 
be made to meet all the requirements of functional occlusion, more per- 
fectly, by having the patient bite firmly and in every direction. When 
the desired accuracy has been obtained thus, the cusps then may be 
reinforced adequately with solder. 
Adjusting Cusps Without Casts. Where it may be desirable to 
construct the crown without an impression, or a cast, and to make the 
adjustment directly in the mouth, the cusps should be swaged, adapted 
to the edge of the band and band and cusps attached. The crown then 
may be placed in position on the supporting tooth, or root, and the opposing 
teeth closed into it firmly. The soldering may be completed, then, and 
the necessary reinforcement made. In cases where the requirements are 
particularly difficult, this process may be facilitated further by swaging 
the cusps of 28 or 30 gage pure gold. Pure gold, of this thickness, is GOLD TELESCOPE CROWNS 
133 
so much more yielding than 22 karat gold that but little resistance to the 
closure of the teeth into firm occlusion will be offered, and accurate results 
will be insured. 
But cusps made of pure gold should be attached and reinforced with a 
very high grade of solder, because the extreme softness will result shortly 
in wear and the exposure of the solder. 
Making Special Dies. 
Of the various methods for securing suitable cusp forms, or repro- 
ductions of the occlusal surface outlines which will typify the natural 
teeth, and meet the requirements of occlusion, by swaging, but one general 
line of procedure offers absolute certainty and accuracy in all cases. 
Throughout the entire evolution of methods for procuring cusp repro- 
ductions, some “system” of typical dies was in general use until the casting 
process, offering greater possibilities, became the better practice. 
In the construction of crowns of this type, the conditions presenting 
vary in proportion to the degree of the accuracy of occlusion, to the posi- 
tion of the tooth, or root, and its relation to the adjacent teeth, and in the 
length and shape of the band and the depth of cusps required. Hence, 
a ready-made form which will approximate closely the edge of a properly- 
contoured band and occlude accurately with the opposing teeth is not 
always a reasonable expectation. 
If the requirements are to be observed, and the swaging method is 
to be used, the demands of certainty and accuracy are to be obtained in 
the best manner by making an original carving from an imprint of the 
opposing teeth. A special die then may be made from this carving. 
This procedure probably may require more time than other methods, but 
time should not always be the only factor to be considered. 
Dies and Counter Dies. Dies are made for the purpose of conform- 
ing gold plate of suitable thickness to the outlines of the surfaces desired 
and thus reproduced. 
The original reproduction of surface outlines is known as the “die” 
and is made, usually, of an alloy which will withstand stress without 
appreciable change of form, and without being defaced easily. When 
the die has been made a counter-die is obtained by pouring a lower-fusing 
and somewhat softer metal, or alloy, directly upon it. 
For larger work, zinc, or Babbitt metal, is used for the die. Both 
are moderately low-fusing and present dense, hard surfaces. The coun- 
ter-die is made usually of tin, or lead, or of an alloy of these two metals. 
In pouring the softer and lower-fusing counter-die, the metal, or 134 
CROWN AND BRIDGEWORK 
alloy, used must not be overheated in melting and must be poured when 
cool, or poured just before it begins to congeal in cooling. This precau- 
tion is necessary as a means of preventing adhesion between die and 
counter-die by fusion. Coating the surface of the die with whiting, 
Fig. 105. 
Fig. 106. 
mixed with alcohol, just previous to pouring the counter-die is useful 
as a further and supplementary precaution. 
The counter-die usually should be made of a metal, or alloy, softer 
in character than that of which the die is made, as well as being lower 
in fusibility. The use of a softer metal, or alloy, for the counter-die 
presents an advantage because it offers less resistance and yields more 
readily in swaging. By yielding more readily, the gold being swaged is 
less likely to be torn or stretched. GOLD TELESCOPE CROWNS 
135 
But for small work, such as the swaging of cusps, the die and counter- 
die both may be made with fusible alloy. Two different alloys, one of 
higher fusibility than the other, would be less likely to become attached 
to each other in pouring one upon the other; but the use of two different 
alloys is unnecessary if the precautions indicated are taken. 
Dies made of fusible alloys may be obtained in a very simple manner 
by pouring directly into a mold made in moldine. Moldine is composed 
of potters’ clay and glycerin. The lower-fusing fusible alloys may be 
poured directly into plaster impressions, or into compound impressions. 
Fig. 107. 
Fig. 108. 
Carved Cusps and Special Dies. The technical procedure involved 
in carving special cusps and in making special dies requires the taking of 
a bite and impression, and the making of casts. 
When the cast, with band in place, has been mounted upon the articu- 
lator (Fig. 105), all surfaces of plaster in close proximity with the 
band should be varnished with collodion, sandarac, or liquid silex. The 
band now should be filled with thin, well-mixed plaster, into which the 
occlusal surfaces of the opposing teeth are imprinted by closing the 
articulator firmly. (Fig. 106.) 
The accurate reproduction on the cast, of the teeth adjacent to the 
band, serves to sustain and prove the proper relationship. When the 
plaster in the band has crystallized, the articulator should be opened and 
the band, with its plaster contents, detached from the cast in a manner 
which will preserve its definite outline and relationship. The surplus 
plaster around the outer edge of the band should be removed first with 
a small, sharp carving instrument. This leaves the plaster remaining 
within the band somewhat crude and irregular in surface outline, but 
accurate in so far as concerns occlusion. (Fig. 107.) 
Artistic results in proportion to the degree of skill possessed by the 
operator may now be obtained by carving and reproducing the typical 
outlines of the natural tooth crown. This may be done without destroy- 
ing the points of contact which insure accuracy of occlusion. (Fig. 108.) 136 
CROWN AND BRIDGEWORK 
Impression compound and certain special forms of hard wax are used 
also instead of plaster. The use of any of these compounds, however, 
is not so reliable as plaster because of the tendency to flake or chip in 
carving, and because of their susceptibility to change of form in the 
subsequent process of securing the mold for the die. 
Fig. 109. 
Fig. 110. 
In carving it is not altogether necessary that absolutely correct 
anatomical outlines should be reproduced. Nevertheless, the masticatory 
purposes of cusps, inclined planes, ridges and sulci should be thoroughly 
understood and the fundamental principles thereof should be observed in 
producing the artificial occlusal surface. Moreover, the age of the patient 
and the contour of the natural teeth, which have resulted from wear, 
should be the guide. Fig. 109 shows such compromise carving. 
The most generally useful and the simplest method of making special 
dies is known as the direct method. In this procedure, the band, with 
its plaster cusps, is imbedded in a metal ring (Fig. no), filled flush 
with its edge, with moldine, with cervical end down, until only the plaster 
cusps are exposed, and exposed even with edge of band. The rubber 
ring, which is a part of moldine “outfits,” is then placed over this (Fig. 
in), and fusible metal poured directly against the plaster cusps, thus 
forming a fusible metal mold, or what is known as a counter-die. The 
cusps now may be swaged into this by using No. 1 or No. 2 buckshot, or 
ingots, or swaging plugs made of tin and lead. (Fig. 112.) GOLD TELESCOPE CROWNS 
137 
Fusible alloy “outfits” are made for this and for other similar pur- 
poses. They include moldine and both metal and rubber rings. 
In melting, the fusible alloy should never be overheated. And in 
the making of dies for any purpose it should be poured just before it 
begins to congeal. In pouring the fusible alloy directly upon the plaster 
Fig. nt. 
Fig. 112, 
Fig. 113 
cusps a smoothness of surface will result if the plaster is thoroughly dry. 
This precaution should be taken always. 
In the absence of suitable swaging slugs, or ingots, a die made of the 
same fusible alloy may be obtained by lightly coating the surface of the 
original counter-die with whiting, mixed with alcohol, adjusting the rub- 
ber ring and pouring directly upon it. The two may be separated easily, 
provided that the fusible alloy is not poured when too hot. This pro- 
cedure affords a die and counter-die of the same alloy. (Fig. 113.) 
Swaging. 
Swaging is the process of adapting or conforming plate gold, or other 
metals or alloys, to the outlines of the surface of the die. 
In the process of swaging, the surfaces of the dies should be oiled. 
This facilitates the procedure and prevents the gold from adhering to the 138 
CROWN AND BRIDGEWORK 
dies. Defacing the gold is to be prevented by stretching a piece of rubber 
dam over it before driving it into the counter-die. This precaution also 
prevents any small flakes of die metal from adhering to the surface of 
the gold. Any danger of tearing the gold may be reduced to a minimum 
by swaging first, between the dies, a few layers of heavy tin foil, covered 
with rubber dam. 
Fig. 114. 
The gold, used for swaging cusps, should be of the same karat and 
color as the gold used for the band, and should be of 28 gage thickness, 
although 29 gage, and even 30 gage, is used. A disk, somewhat larger 
than the diameter of the cusps to be formed, should be cut and should 
be annealed frequently during the swaging process. A round or disk- 
shaped piece of plate gold will yield more readily to the swaging process, 
and will have less tendency to overlap at the angles. All unnecessary sur- 
plus should be removed before the final swaging. Steady and uniform 
pressure, such as will result from the use of a press of adequate power, 
probably is the best means of swaging. In the absence of a press a 
heavy hammer and a few well-directed blows will answer the purpose. 
Adjusting Cusps to Band. 
When the swaging of the cusps, made by any method, has been com- 
pleted and when all surplus gold has been trimmed away, the edge of the 
cusps should be adjusted carefully to proper relationship and contact with 
the band. 
The final trimming should be done with a fine, flat-surface gold file, 
and may be best accomplished by holding the file steady and carrying the GOLD TELESCOPE CROWNS 
139 
cusps backward and forward over its flat surface. When trimmed thus, 
until the edge approximates evenly with the edge of the band, and the 
desired occlusion obtains upon closure of the articulator (Fig. 114), the 
cusps should be soldered to the band. 
Soldering. All necessary reenforcement of the cusps sufficient to 
withstand constant and continued attrition may be made with solder 
simultaneously with the attachment of the cusps to the band. Filling 
the cusps with solder previous to their final attachment to the band facili- 
tates the soldering. 
Fig. 115. 
During the process of soldering, the relationship between cusps and 
band should be sustained securely. This is to be accomplished best by 
using automatic soldering pliers designed for the purpose, as illustrated 
in Fig. 115. Wiring cusps to the band is objectionable for the same 
reasons previously mentioned in connection with soldering the band. 
Before soldering, both the band and the cusps should be treated to the 
acid bath and then washed freely with water. When adjusted in the 
pliers, flux should be applied and fused and the parts then united with 
22 or 20 karat solder. The necessary reenforcement should be made with 
the same karat solder. Any perforation resulting from swaging should 
be filled first with plate or foil gold, by which means no trouble will 
be experienced in filling in with solder. 
Finishing. When the soldering has beer, completed, the crown should 
be treated again to the acid bath to dissolve remaining borax. It should 
be finished down with carborundum stones and disks and polished. 
Seamless Method. 
The seamless method of constructing gold telescope crowns involves 
the formation of the entire crown with a single piece of gold, through 
swaging. While many “systems” have been devised for this particular 
style of construction, a close observation of the relative advantages, com- 
pared with the sectional method, fails to afford any real or practical evi- 140 
CROWN AND BRIDGEWORK 
dence of special merit in this process. Therefore, it is to be regarded as 
an obsolete method, and as one affording no advantages over a manufac- 
tured or ready-made crown. 
Gold Crowns Applied to Separated Molar Roots. 
Where the roots of molar teeth have become separated at the bifurca- 
tion as the result of extensive disintegration of the natural crown, and 
where each individual root remains healthy and firm in its attachment, the 
application of a gold crown may be indicated. At times a crown will not 
only restore the separated roots to their former usefulness, but also will 
Fig. 116. 
preclude impaired occlusion of the adjacent teeth, as a result of migration 
following the loss of such roots. 
The retention of the roots of the first permanent molars, particularly 
during early life, by any adequate method of restoration is an important 
consideration. 
When retention is indicated and restoration is demanded, the indi- 
vidual roots should be prepared carefully and each root built up separately 
with amalgam (anchored with a post, or anchored by other means of 
mechanical retention) until it presents a shape suitable for the perma- 
nent attachment of a separate band. (Fig. 116.) 
Separate bands should he fitted to each root, the occlusal ends trimmed 
to allow for cusps, and contoured to approximate each other, and to 
restore contact with adjacent teeth. 
A bite in wax and an impression in plaster should be obtained, and 
the casts mounted upon the articulator. When the articulator has been 
separated the bands should be detached from the cast in such manner as 
to preserve their outlines and admit of accurate replacement. They 
should be readjusted to position on the cast and united securely with hard 
wax. After this, the bands are removed, and the cervical half imbedded 
in investment material. Their relationship is then permanently sustained 
with 22 karat solder. Uniting the occlusal ends, only, will leave a free, 
clean, interproximal space. (Fig. 117.) GOLD TELESCOPE CROWNS 
141 
Following this, the united bands should be replaced upon the cast and 
the cusps formed by any method desired, and formed as though for a 
single band. 
In attaching bands to cusps, however, care must be exercised to 
prevent refusing the solder with which the bands were united previously, 
thus destroying the relationship between them. The use of a lower karat 
Fig. i 17. 
Fig. 118. 
of solder will preclude such a mishap, and to facilitate the procedure 
further, the cusps should be filled with solder immediately following their 
proper adaptation and adjustment, and previous to attaching them to the 
bands. The use of an anti-flux (whiting and alcohol) is a precaution, 
also, which it is well to observe. 
Restoring Single Roots of Molar Teeth. 
A single molar root which possesses sufficient strength to warrant re- 
tention and restoration often may be retained and made serviceable by 
the application of a gold crown. 
The occlusal surface of a gold crown, supported by a single root, may 
be made to afford a continuous masticating surface by extending it 
mesially, or distally, until it effects approximal contact with the crown 
of the adjacent natural tooth. (Fig. 118.) The contact point between 
the crown and the adjacent natural tooth, however, should be sufficient 
only to prevent any tipping of the root from the stresses of occlusion. 
And, for prophylactic reasons, it should rest closely to the occlusal sur- 
face and be smooth and well rounded. 142 
CROWN AND BRIDGEWORK 
Gold Crowns Acting as Cantilever Bridges. 
Small intervening spaces between two gold crowns may be bridged 
over by the crowns in such manner as to afford an uninterrupted masti- 
cating surface. (Fig. 119.) This type of restoration might be indicated 
and warrantable in cases where a very small space existed; but, where the 
space is sufficiently large to accommodate a properly formed pontic, an 
assembled bridge would be the better procedure. 
Fig. i 19. 
Open-Face Crowns. 
A type of partial crown with telescoping peripheral band, used as a 
means of obtaining attachment for bridgework, and used much more often 
than it should be, is known as an “open-face” crown. 
This type of crown has a limited field of usefulness. It is better than 
a full gold crown, only because less gold is displayed. And it is better 
than some other methods of attachment to the crowns of natural teeth 
for the anchorage of bridgework, only because in its application less 
mutilation of the natural tooth crown is necessary. 
A favorable degree of strength in the attachment to the supporting 
tooth, with a minimum of mutilation of natural crown are the chief assets 
of the open-face crown. But these assets obtain at the expense of 
esthetics. 
Indications, In cases where the requirements of esthetics must give 
place to the requirements of strength, and in cases where the age of 
the patient, or the stability of the tooth, or other reasons which do not 
warrant a more extensive preparation of the natural crown are present, 
the application of an open-face crown may be indicated as being the 
simplest means of obtaining attachment for bridgework—especially when 
the attachment is to be made to the cuspid teeth. GOLD TELESCOPE CROWNS 
143 
The natural shape of the crowns of the cuspid teeth is favorable to 
a more or less accurate adaptation of the open-face crown without exten- 
sive preparation. With rare exceptions, its application should be confined 
to these teeth. 
Construction. In the construction of an open-face crown, when the 
supporting natural crown has been prepared properly, a wire measure- 
ment should be taken and a wide band made of 28 gage, 22 karat gold. 
The band should be wider than the full length of the natural crown, and 
its edges should be cut straight, and soldered with 22 karat solder. 
A 
B 
C 
D 
Fig. 120. 
The gingival edge then should be trimmed to follow the gingival curva- 
ture and made blunt and smooth. The band now should be forced to 
place on the supporting tooth until this edge passes just within the 
gingival border. (Fig. 120 A.) The labial portion then should be 
trimmed away until only a narrow band presents around the labio- 
gingival border, after which the lingual surface is cut away at the mesio- 
lingual and distolingual angles. (Fig. 120 B.) This will form a band 
exposing both labial and lingual surfaces of the natural crown, but cover- 
ing the mesial and distal surfaces to the incisal angle. 
A separate piece of plate gold of the same thickness and karat, but 
with some surplus, then should be shaped to conform to the lingual curva- 
ture of the band (Fig 120 C), and then attached to this edge of the band 
with 22 karat or 20 karat solder. After soldering, all surplus should be 
trimmed away until a smooth and continuous surface presents. The 
crown should then be placed in position on the supporting natural crown 
and the final adaptation completed by burnishing. (Fig. 120 D.) 
Pure gold, 28 gage, or even 30 gage, may be used to form the lingual 
surface, and its use will afford increased opportunity for obtaining ac- 
curacy of adaptation to this surface of the natural crown. Where pure 
gold is used, howevei, it must be reinforced adequately with a high grade 
of solder, after the burnishing has been completed. 144 
CROWN AND BRIDGEWORK 
Manufactured or Ready-made Gold Crowns. 
Manufactured or ready-made seamless gold crowns are procurable 
in a large variety of sizes and typical forms for bicuspids and molars. 
They are made of 30 gage, 22 karat gold. 
In the use of ready-made gold crowns, a measurement is taken and 
a size of crown approximating the size of the tooth to be restored is 
selected. In effecting the adaptation, the gingival edge is trimmed grad- 
ually until a length which will accommodate the requirements of occlusion 
obtains. Restoration of contact and preservation of alinement with adja- 
cent natural teeth is observed thereafter, and gingival adaptation is made 
as accurate as possible by the use of contouring pliers. The occlusal 
surface then should be reinforced adequately with solder. 
If any degree of accuracy is secured, the time required to adapt a 
ready-made crown properly to all requirements will usually equal, if 
not exceed, the time required to construct one for the case. And the 
results will be much less satisfactory. 
Application of Casting Process. 
With the advent and successful application of the casting process, the 
construction of crown and bridge work was revolutionized, and many 
former methods of procedure abandoned. 
In the construction of gold crowns, the use of dies and of die-plates 
becomes unnecessary, and swaging is resorted to only as a supplementary 
procedure. All of the combined advantages of the sectional and seam- 
less crown methods may be obtained, and better adaptation and more 
definite and more artistic results are made possible. 
In its application, the band may be long or it may be short. It may 
be trimmed to allow for the full thickness of cusps, or it may be trimmed 
to be just free of the occlusal planes of the opposing teeth. Or no band 
at all may be used. And the technical procedure of construction may be 
conducted upon the tooth or root in the mouth directly, or it may be 
transferred to the laboratory and done on casts. 
Two general lines of procedure are followed. These may be desig- 
nated as the direct and as the indirect methods. Each has its advantages 
and its respective field of application and usefulness. 
Direct Method. 
In the application of the direct method to the construction of gold 
crowns, the casting process involves the formation of the cusps only, and 
the details of procedure are applied to the mouth directly. This eliminates GOLD TELESCOPE CROWNS 
145 
the taking of impression, the making of casts, the use of dies or die- 
plates, and swaging. 
Wherever the direct method may be followed, much time is saved, 
and, since no reproduction is as accurate as the original, even greater 
accuracy is possible, in proportion as correct technic may be developed. 
Telescoping Peripheral Band. The simplest method of forming 
the cusps by the casting process involves the making and fitting of a 
wide peripheral band, the formation of the cusps in casting wax, directly 
Fig. 121. 
on the supporting tooth, or root, in the mouth, and their reproduction in 
gold by casting directly to the band. 
Although physical union between band and cusps does not result, or 
is not insured, all requirements of adaptation are satisfied and complete 
physical union may be insured by the use of a very small bit of solder, 
after the casting has been completed. 
The band should be made of 28 gage, 22 karat gold plate and trimmed, 
fitted and contoured to meet all requirements indicated for swaged cusps. 
When these requirements have been met, the band should be placed 
in position on the supporting tooth in the mouth (Fig. 121 A), and 
casting wax of proportions just sufficient to fill it completely and to 
accommodate an imprint of the opposing teeth, should be made plastic 
by immersing it in hot water. It then should be pressed firmly to place 
inside of the band. The opposing teeth should be closed compactly into 
the wax and all the varying movements of functional occlusion observed 
while the wax is still plastic. (Fig. 121 B.) This latter precaution is 
exceedingly necessary as a means of insuring an accommodation for all 
movements of occlusion in the finished crown, after casting. 
Casting Wax. In the use of casting wax for this purpose, the best 
results are obtained always, by heating the wax in hot water. The tem- 
perature of the water should be just sufficient to insure uniform plasticity, 
without destroying integrity. If overheated, it will not offer resistance, 146 
CROWN AND BRIDGEWORK 
its integrity will be destroyed, and molding to definite, accurate outlines 
will be impossible. 
When the imprint of the opposing teeth has been obtained satis- 
factorily, the band and wax cusps should be removed carefully from the 
supporting tooth. The interior of the band should be filled with casting 
investment compound, exercising care to exclude all contained air. Any 
contained air would destroy accuracy of adaptation. Immediate filling 
sustains the relationship of the wax and band, and facilitates carving. 
(Fig. 122 A.) 
Fig. 122. 
Fig. 123. 
Carving. When the investment compound has crystallized, the sur- 
plus wax should be trimmed down until even and flush with the band. 
The wax cusps then should be formed by carving, in which a reproduc- 
tion of typical inclined planes, sulci, marginal ridges and grooves should be 
secured. (Fig. 122 B.) 
Additional Contouring. Where the premature loss of an adjacent 
natural tooth precludes the restoration of contact by contouring the band 
(Fig. 123 A), the occlusal surface restoration may be made with the wax. 
(Fig. 123 B.) 
Additional reinforcement, or additional contouring of the band, also 
may be made with wax at this time. 
Investing and Casting. When all requirements have been observed, 
the sprue-former should be attached securely, usually at a point where 
the wax is thickest (Fig. 123 C), and the crown then invested and cast. 
Just previous to investing, it is well to submerge the crown in water GOLD TELESCOPE CROWNS 
147 
until the investment compound previously placed in the band is saturated. 
This precaution insures a close attachment of the freshly-made mix to 
be used in the final investment. 
In order that the completed crown may be of uniform color, it is 
essential that a grade and color of gold similar to that of which the band 
is made, be used in casting the cusps. 
The same grade of gold may be used without danger of melting the 
band, because the band is protected by the investment. The addition 
of a small proportion of solder to the gold to be cast, however, will reduce 
Fig. 124. 
the fusibility and increase the fluidity, thereby insuring a better union 
with the band. Scrap gold may be used, provided it is of similar color, 
and provided also that it is melted and refined previously. 
When the casting has been made, the crown should be cleaned in the 
acid bath. When all traces of investment compound and of acid have 
been removed, physical union may be insured by fusing a small bit of 
22 karat or of 20 karat solder into the joint. The crown then should 
be finished and polished. 
Variations. 
While more, or less, accurate results are obtained from the simple 
technic just described, several variations of technic, insuring even greater 
accuracy, may be followed. 
Accurate Interior Adaptation. The most accurate method of fitting 
the interior of the crown to the supporting tooth, or root, consists in 
taking an impression and making an amalgam cast of the tooth, or root, 
previous to making the band. A coping of thin, pure gold, about 36 
gage, is then adapted closely to the amalgam cast, and trimmed to follow 
the gingival curvature uniformly around the entire circumference without 148 
CROWN AND BRIDGEWORK 
passing beneath the gingiva. When the coping has been made, the band 
is made and fitted as usual, and in accordance with all requirements. 
The pure gold coping then is placed in position upon the supporting 
tooth, the band placed over it, and casting wax then forced firmly into 
the interior of the band and over the coping, and the requirements of 
occlusion observed. The same technic of investment and casting is then 
followed. 
Irrespective of the length or shape of the supporting tooth or root, 
absolute accuracy in the interior adaptation of the crown is insured, and 
Fig. 125. 
the highest possibilities of crown construction in which a peripheral 
band is used may be obtained from this technic, which is used extensively 
by Dr. W. D. N. Moore. (Fig. 124.) 
Short Roots. In the construction of gold crowns for short roots, 
where the occlusal surface of the crown would be very thick and unneces- 
sarily heavy, if constructed by either of the preceding methods, one or the 
other of two different procedures should be observed. 
First: The root should be restored previously or built up to a more 
favorable height with amalgam. In very short roots this is the better 
procedure always. And the restoration should be made to a point approxi- 
mating the length of the band when fitted and contoured. The restoration 
then should be finished and polished and the band made and the crown 
constructed as indicated. 
Second: Where the root is not short enough to require restoration 
with amalgam, and yet where the cusps would be unnecessarily thick 
and heavy, the thickness of the wax may be reduced by the use of a 
“suction carver” designed for this and similar purposes. (Fig. 125.) 
In the use of this instrument all unnecessary thickness of wax should 
be reduced from the interior of the crown just after the wax has been GOLD TELESCOPE CROWNS 
149 
molded to the requirements of occlusion. It should be reduced in such 
manner, however, as will leave a shoulder of wax remaining around the 
entire circumference of the interior of the band. The formation of this 
shoulder, when reproduced in the casting, will cause the finished crown 
to rest firmly upon the end of the supporting root when mounted. (Fig. 
126.) 
Any type of gold crown always should rest firmly upon the end of 
its supporting root. Crowns so constructed assume their proper position 
Fig. 126. 
A 
B 
Fig. 127. 
on the supporting root much as an inlay goes to its place in a cavity. 
It is impossible to force them too far within the gingival border; there- 
fore, less discomfort is occasioned, less irritation of the investing tissues 
is produced and less cement is required in mounting. And all of these 
features are desirable and advantageous. 
Another variation of technic consists in making a narrow band and 
utilizing it for the purpose of obtaining gingival adaptation only, and 
then forming the crown entirely in wax. In this procedure a narrow 
band, made of 30 gage or of 32 gage gold or platinum, is fitted to 
conform to the requirements of gingival adaptation. Casting wax of 
proportions adequate to the size of the crown is then made plastic and 
modeled over the supporting root with band in position. When molded 
to contact with the band, and to meet all of the other requirements, band 
and wax are removed, their relationship sustained by filling with invest- 
ment compound, then carved, invested and cast. 
In this technic the band is used as a means of obtaining and insuring 
a degree of accuracy in the adaptation of the gingival edge of the crown, 
which would not be possible by the use of wax alone, and good results 
may be obtained. 
Still another variation of technic, suggested by Dr. C. E. Meerhoff, 
consists in making the band somewhat wider than the length of the sup- 
porting tooth crown and then slitting the surplus occlusal end of the band 150 
CROWN AND BRIDGEWORK 
and overlapping the flaps thus formed upon the end of the root. (Fig. 
127 A.) Wax then is molded and carved to meet the requirements and 
the casting made. (Fig. 127 B.) A good adaptation to the supporting 
root is insured by this method. 
Indirect Method. 
The indirect method involves the taking of the bite and impression 
and the making of casts. This method is indicated whenever it is desir- 
able to transfer the technical procedure from the patient to the laboratory, 
and whenever accuracy may be obtained with greater facility by the 
use of casts. If an accurate bite and impression and an accurate cast may 
be secured, the indirect method may be used successfully in any of the 
preceding technical procedures. 
When the band has been fitted, the bite should be taken in base-plate 
wax and the impression then taken in plaster. The band usually will be 
removed with the impression. If it is not removed it should be detached 
from its supporting root and placed carefully and accurately in place in 
the impression. 
After varnishing the impression and before pouring the cast, the 
interior of the band should be painted with melted wax. This precaution 
will insure its subsequent detachment from and its accurate replacement 
upon the cast. The cast then should be poured. A good grade of hard 
plaster should be used. When the cast has been separated from the im- 
pression, the bite should be adjusted accurately and both mounted upon 
the articulator. A very hard plaster, or compound, should be used in 
mounting. 
When the articulator has been separated and the wax bite removed, 
all unnecessary surplus should be trimmed away. The band then should 
be warmed and detached carefully, cleaned in the acid bath and replaced 
accurately in position on the cast. 
Casting wax now may be made plastic, molded and carved as desired, 
and the crown invested and cast as indicated in the direct method. 
Where a peripheral telescoping band is used, the application of the 
indirect method is seldom productive of any very great advantages. In- 
deed, one of the features of the casting process lies in the fact that much 
of the technical detail formerly transferred to casts, necessarily, now may 
be accomplished in the mouth directly. 
Shoulder Crowns. 
The gold telescope crown, however, is not limited to the use of the 
peripheral band. Where a peripheral band is used, the adaptation of GOLD TELESCOPE CROWNS 
151 
the gingival edge is made by overlapping the periphery of the root, thus 
making what is known as a “lapped” joint. A lapped joint may, or 
may not, preserve a close continuity between crown and root, and may, 
or may not, become a source of irritation. Both depend upon the closeness 
and smoothness of the adaptation at the immediate line of junction 
between crown and root. 
Wherever a lapped joint may be made in such manner as to restore and 
preserve a close, smooth continuity between crown and root, without 
impingement upon the investing tissues, it will not be irritating to these 
tissues. But, unless the adaptation of a lapped joint does conform to 
these requirements, it will necessarily be a source of irritation. And, if 
it is a source of irritation, it will be a menace to health and a positive 
injury to these tissues. 
The devastating influence of irritation which is invited by faulty 
adaptation of a lapped joint may be diminished greatly, or may be over- 
come entirely by the formation of a shoulder at the gingival line, and 
by the close adaptation of the gingival edge of the crown to this shoulder. 
By this means a “butted” joint between crown and root is formed, and 
a well-adapted and well-finished “butted’ jointed unquestionably is the 
ideal procedure for conserving the normal conditions. 
Indications. The demands of prophylaxis require that every means 
of eliminating, reducing or minimizing any and all forms of mechanical 
irritation of the investing and environmental tissues must be observed. 
Therefore, if a peripheral band means irritation, and, if irritation is 
to be avoided by the formation of a shoulder at the gingiva and a shoulder 
crown restoration—then, a shoulder crown is indicated, wherever its suc- 
cessful construction may be insured. It is certain that the application 
of a shoulder crown which fits, conserves and reproduces normal condi- 
tions better and more closely than any other. And it is certain, also, 
that it is difficult to improve upon normal conditions. 
Full Shoulder Crowns. 
For these very important reasons, full shoulder crowns must be re- 
garded as the ideal means of crown restoration, whenever and wherever 
the remaining natural crown may be prepared properly, and whenever 
and wherever accuracy of adaptation may be insured. 
Because of the difficulty of conforming accurately, or adapting a plastic 
substance like wax to the entire periphery of a tooth or root, and to all 
other requirements, in the mouth, full shoulder crowns may be success- 
fully constructed only by means of the indirect method. 152 
CROWN AND BRTDGEWORK 
Indirect Method. The technical procedure involved in the construc- 
tion of full shoulder crowns in gold is identically the same as that used in 
the construction of full shoulder crowns in porcelain. 
Unit Impression. The first essential requirement is a good, accurate 
impression of the remaining natural crown, as prepared, and including the 
shoulder as a single unit. 
This impression is obtained, first, by carefully trimming and fitting an 
impression band or cup, which should always be done before the shoulder 
Fig. 128. 
is formed, as this procedure avoids discomfort. Seamless impression 
bands, made of thin copper and aluminum, and in various sizes, are ob- 
tainable for this purpose. When a band of suitable size has been selected, 
or has been made for the case, it should be fitted to slip just freely over 
the remaining natural crown, including its shoulder, then trimmed to 
follow the gingival curvature closely. 
When the impression band has been fitted, it should be filled, with a 
slight surplus, with impression compound made plastic in hot water, or 
over the flame. A special, hard impression compound, made in stick form, 
is prepared for this purpose. Band and plastic compound then should 
be forced firmly over the remaining natural crown and pressed rootwise 
until an imprint of the shoulder around the entire circumference is ob- 
tained. The impression should be held firmly in place until chilled with 
a spray of cold water, then removed carefully. Accuracy, definiteness 
and exactness in details must obtain in the unit impression. 
Amalgam Cast. When a satisfactory impression has been thus ob- 
tained (Fig. 128 A), it should be imbedded in plaster in such manner as 
to form a matrix which will in turn form a base, or root extension, to the GOLD TELESCOPE CROWNS 
153 
amalgam cast. (Fig. 128 B.) A good grade of quick-setting amalgam 
should be mixed thoroughly and packed carefully into the impression, and 
the surrounding plaster matrix. 
The amalgam cast of the prepared natural crown is useful only as a 
means of obtaining accuracy in the adaptation of the crown to the root 
itself. (Fig. 128 C.) 
The requirements of occlusion, and of restoration of alinement and 
contact demand a cast which includes several adjacent teeth, together 
Fig. 129. 
Fig. 130. 
with the amalgam cast in its proper relationship, both to the adjacent and 
to the opposing teeth. 
Several different lines of technical procedure may be followed in ob- 
taining the maximum of requirements in this connection, but uniformly 
accurate and reliable casts should be obtained in the following manner: 
After securing the impression of the remaining tooth crown as a single 
unit, in the manner indicated, a coping of base-plate gutta-percha, or of 
temporary stopping, should be molded over the remaining natural tooth 
crown to fill the space and to conform to the general outlines of the tooth 
to be restored. This coping, however, should not be brought into contact 
with the crowns of adjacent teeth, but the surfaces adjacent to the tooth 
being restored should be allowed to remain exposed freely. (Fig. 129.) 
An impression to include several adjacent teeth, with this coping in 
place, now should be taken in plaster. The coping will be removed with 
the impression. (Fig. 130.) The bite then should be taken and the re- 
maining details transferred to the laboratory. 154 
. CROWN AND BRIDGEWORK 
When the amalgam has crystallized, the impression and cast should 
be placed in hot water and separated. The surplus base of the amalgam 
cast, which has been formed by the plaster matrix, now should be made 
somewhat conical in shape and finished with smooth disks. It is well, 
Fig. 131. 
Fig. 132. 
Fig. 133- 
also, to designate the buccal surface by some form of marking. (Fig. 
131. This will avoid confusion or mishap in placing the cast into posi- 
tion in the plaster impression, or in the subsequent construction of the 
crown. 
When the plaster impression has been varnished, the amalgam cast 
should be placed in position in the coping made of temporary stopping, 
or gutta-percha, and its proper position sustained with melted wax. (Fig. 
132. The certainty and the facility with which the cast may be placed 
in position in the coping of temporary stopping, or gutta-percha, gives 
immediate evidence of the advantage obtained by observing this detail. 
The cast, then, should be poured. 
Absolute indestructibility of the crowns of the adjacent teeth on the 
cast may be obtained by filling their imprints in the impression with 
amalgam before pouring the cast. When this feature is observed the 
head end of a short, blunt pin should be imbedded in the amalgam as a 
means of sustaining it securely as a part of the resultant plaster cast. 
(Fig. 133.) And the amalgam should be allowed to crystallize before 
pouring the cast. GOLD TELESCOPE CROWNS 
155 
When the cast has been obtained (Fig. 134), the bite should be ad- 
justed accurately to place, and both mounted on the articulator. When 
separated, the amalgam cast should be detached from the plaster cast in 
such manner as will admit of its ready and accurate replacement. 
Fig. 134- 
Fig. 135 
Fig. 136, 
After thus detaching and replacing the amalgam cast, its exposed sur- 
faces should be lubricated with thin oil and the desired crown restoration 
built with casting wax. 
When the wax restoration has been formed and contoured to meet all 
requirements, a provision to allow for shrinkage of the casting must be 
made. Such a provision may be secured by cutting a slit entirely through 
the wax on both mesial and distal sides of the band, the slit extending 
from the cusps to the gingival edge. (Fig. 135.) 
The sprue-former then should be attached securely at a favorable 
point and the restoration gently detached from the cast, invested and cast. 
After casting, removing all surplus and roughly finishing, the crown 
should be fitted to the amalgam cast. Driving to place by swaging may 
be necessary, but, if necessary, the amalgam cast will withstand it, 156 
CROWN AND BRIDGEWORK 
and accuracy of adaptation is insured. When the desired adaptation is 
obtained, the slits may be filled with high-grade solder and the crown 
finished and polished. (Fig. 136.) 
Any effort to make the casting without thus, or in some similar man- 
ner, providing for shrinkage, will result only in failure. 
Partial Shoulder Crowns. 
Partial shoulder crown restorations are seldom used as a means of 
restoring the natural crown as a single unit. But they are used mainly 
and more or less extensively as a means of obtaining attachment for 
bridgework. Restorations of this type are known as “three-quarter” 
crowns and are applicable to the anterior as well as to the posterior teeth. 
In the technical details of construction, either the direct or the indi- 
rect method may be used. 
Indirect Method. In the use of the indirect method, the same tech- 
nical details as apply to the construction of full shoulder crowns may be 
followed with good results. And the possibility of final swaging after 
casting is to be regarded always as an advantage of importance. 
Direct Method. In the application of the direct method of construct- 
ing partial shoulder crowns, accurate results are to be obtained only in 
proportion as a careful and accurate technic is developed. 
The most highly developed technic is suggested and used by Dr. E. T. 
Tinker. This consists in making and fitting the impression band to con- 
form to all of the requirements previously indicated. When thus fitted, 
it is filled with casting wax heated in hot water until the proper plasticity 
obtains. Band and wax are carefully forced to place on the natural tooth 
crown until gingival adaptation is insured. 
It is removed and all surplus wax extending or projecting beyond the 
band is trimmed away. Gingival adaptation of wax is perfected by trim- 
ming down to the desired point, or by the addition of a small bead of 
melted wax at some point, if necessary. Where melted wax is added, 
a fine spray of hot water is applied to the surface of the wax and it is 
forced to place again. This procedure is continued until the desired 
adaptation at the gingival line is obtained. 
Band and wax then are held in place firmly, and the continuity of 
the band is destroyed by cutting it in two with a small, round bur. A 
small spray of cold water is directed upon the bur while cutting the band 
to prevent any overheating or distorting of the wax. The band is re- 
moved, and the gingival adaptation of the wax completed. 
In posterior restorations, a spray of hot water is directed upon the GOLD TELESCOPE CROWNS 
157 
occlusal surface of the wax. By this means this surface of the wax is 
made sufficiently plastic to permit the firm closure of the opposing teeth. 
When this feature has been observed, all further requirements in the 
form of a reproduction of inclined planes, sulci, marginal ridges and 
grooves by carving are carried into effect. Then the sprue-former is 
attached securely and the pattern carefully removed, invested and 
cast. A special, hard, casting alloy always should be used for partial 
shoulder crowns. 
After the casting has been made, it should be cleaned in the acid bath 
and then finished with stones and disks. 
The final adaptation to the natural tooth crown may be greatly facili- 
tated by carbonizing the casting first and then adjusting it to place on 
the supporting tooth crown. Carbonizing is accomplished by holding the 
casting in a yellow flame and allowing it to cool slowly. When car- 
bonized and forced gently to position on the tooth, all points, or surfaces, 
which bind, or which prevent perfect seating of the gold are indicated 
by bright spots. These points should be relieved with small stones and 
the process of carbonizing, replacing and grinding continued until the 
desired adaptation is obtained. 
The typical application of partial shoulder crowns both to anterior and 
posterior teeth is illustrated later in Fig. 267. CHAPTER XI. 
GOLD TELESCOPE CROWNS WITH PORCELAIN 
FACINGS. 
Gold telescope crowns subscribe to all requirements of crown restora- 
tion, except in two particulars. 
In their application, pulp conservation is possible. Conservation of 
remaining natural crown is possible. Accuracy of adaptation is possible. 
Restoration of function is possible. Strength of attachment to the sup- 
porting tooth, and a degree of indestructibility, which will insure 
permanency, are possible. 
And, yet, however well gold crowns may subscribe to all these require- 
ments, they do not meet the requirements of esthetics; nor do they sub- 
scribe to the highest possibilities of prophylaxis and of sanitation. 
These two important requirements may be obtained by the use of 
porcelain, only. But porcelain is a friable substance, and crown restora- 
tions made entirely of porcelain are not applicable universally. They are 
not applicable universally as a single unit restoration because a degree 
of indestructibility not possessed by porcelain is demanded frequently. 
And they are not applicable where the restoration is to serve as an attach- 
ment for bridgework, because opportunity for attachment to them is not 
afforded. 
All of the advantages of the full gold telescope crown, however, may 
be combined with an observation of the requirements of esthetics. These 
combined advantages are obtainable by the use of porcelain facings in 
combination with gold telescope crowns. 
Indications. This type of crown construction is useful, and is in- 
dicated specially, in several different classes of cases. 
First: In those cases where it is desirable to conserve the vitality 
of the pulp. 
Second: Where it is desirable to conserve as much of the natural 
tooth crown as possible. 
Third: Where the requirements of strength in the attachment of the 
crown to the supporting tooth make the telescoping principle of attach- 
ment preferable to the dowel principle, irrespective of whether the tooth 
has a vital pulp or is pulpless. 
158 GOLD TELESCOPE CROWNS WITH PORCELAIN FACINGS 
159 
Fourth: Where the requirements of stress demand indestructibility. 
Fifth: Where the use of gold as a means of affording opportunity 
for the attachment of bridgework is necessary. 
Sixth: Where the requirements of esthetics preclude the display of 
gold, and demand the use of porcelain. 
Application. The application of a type of construction which will 
afford all of these combined advantages is particularly useful in the 
restoration of the ten or twelve anterior teeth; or in the restoration of 
all teeth which are within the range of vision and where pulp devitalization 
and the use of dowel crowns is contraindicated. 
Application to Posterior Teeth. 
In the application of this type of construction to the restoration of 
bicuspids and first molars, two different methods of procedure may be 
followed: 
First: The telescoping band may be made and fitted, a replaceable 
facing then adapted to the band, and the crown completed by casting the 
cusps directly to the band and to the backing for the facing. 
Second: The gold telescope crown may be made with swaged cusps, 
and a thin, flat-back porcelain facing adapted subsequently, and soldered 
to the crown. Either method of procedure is productive of good results 
and each has a field of usefulness. 
Advantages of Replaceable Facings. 
The use of replaceable facings is indicated always in preference to 
the use of soldered facings, wherever possible. Replaceable porcelain 
facings are not weakened, primarily, by being subjected to the heat of 
soldering, nor by the influence of expansion and contraction because they 
are not invested with the parts to be united; hence, the finished crown, 
whenever a replaceable facing is used, is a stronger crown. 
Replaceable facings, attached to the basic structure by means of 
cementation are stronger to begin with, and, being cushioned somewhat 
by the cement used in their attachment to the structure, they are less 
liable to fracture. Their replacement with ease and facility, in the event 
of fracture, and the additional advantages obtainable by grinding dupli- 
cates, at the time of construction, and preserving them for future use 
in case of accident, make the use of replaceable facings the preferable 
procedure in all cases. 160 
CROWN AND BRIDGEWORK 
Use of Replaceable Facings and Cast Cusps. The most ideal type 
of construction results from the use of replaceable facings, and from 
casting the cusps directly to band and backing. 
In this procedure a wide telescoping band is made and fitted in accord- 
ance with all requirements. When adapted thus, the completion of con- 
struction can be accomplished best by the indirect method. This involves 
Fig. 137. 
taking the bite with the band in position on its supporting tooth, and fol- 
lowing this with a plaster impression. Before pouring the cast, the interior 
of the band in position in the impression, should be painted with melted 
wax. This precaution will permit of its subsequent detachment from the 
cast, and its accurate replacement thereon. The cast, then, should be 
made in plaster, the wax bite adjusted, and both mounted upon the 
articulator. 
When separated, the band should be detached carefully from the cast 
and cleaned in the acid bath. A replaceable porcelain facing should be 
selected to meet the requirements of size, type and color. The buccal sur- 
face of the band should be cut away (Fig. 137 A), using small, pointed, 
curved shears, until accommodation obtains for the desired and required 
relationship between band and facing with its backing trimmed properly 
and in place. (Fig. 137 B.) 
The reproduction of the root-end inside of the band should be var- 
nished, now, to prevent the wax from adhering to it, and casting wax 
softened and molded over it—sufficient to fill the band. The exposed end 
of the porcelain facing, which is not covered by its backing, should next 
be lubricated, and for the same reason; facing and backing then should 
be forced to place in proper relationship with the band. This relationship 
should be sustained and the imprint of the opposing teeth in the wax 
obtained. Band, wax and facing then should be detached carefully from 
the cast, the surplus wax trimmed away and the necessary contouring and 
carving perfected. The porcelain facing now should be detached, 
the sprue-former attached securely, and the crown invested and cast. In GOLD TELESCOPE CROWNS WITH PORCELAIN FACINGS 
161 
investing, it is extremely necessary that the interior of the band should 
be filled carefully with the investment compound, because the adaptation 
of the finished crown depends entirely upon an observation of this fea- 
ture ; and, also, care should be exercised in covering the exposed backing 
with investment compound, as a means of protecting it during the casting 
process. 
Fig. 138. 
Backings for replaceable porcelain facings are made of gold alloy, 
and of base-metal or nickel alloys. Only those made of gold alloy should 
ever be used in casting. These may be used without danger of fusing, if 
casting into the mold when heated to a red heat is avoided. 
After casting and finishing, the facing should be cemented to place, 
and when the cement has crystallized, the final polishing is given. 
Use of Soldered Facings and Swaged Cusps. 
In the procedure which involves the use of soldered facings and 
swaged cusps, the full crown should be made and completed, primarily. 
In its construction any method of forming the cusps by swaging may be 
used and either the direct or the indirect method is applicable, but a high 
grade of solder (22 karat) always must be used in soldering the band and 
in attaching the cusps. No reinforcement of the cusps should be made 
at the time of their attachment. 
When the crown is completed thus and roughly finished, the buccal 
surface should be cut entirely as indicated in Fig. 138 A, using a thin, 
vulco-carborundum disk for the purpose. 
A thin, flat-back facing of proper size, type and color now should 
be selected. The edges of the crown and of the facing then should be 
ground until the desired and required adaptation and relationship between 
crown and facing is obtained, with an allowance for the backing. 
The facing, then, should be backed with pure gold, 36 gage, allow- 
ing a slight surplus to project upon all surfaces. (Fig. 138 B.) No 
effort to sustain the backing in its relationship to the crown should be 162 
CROWN AND BRIDGEWORK 
made at this time, but it should be burnished to close adaptation. Facing 
and backing then should be placed in position in the crown (Fig. 138 C), 
and the proper relationship between backing and crown designated by 
marking the backing, using a fine, pointed instrument. The facing should 
be removed, the backing placed in proper position and then soldered 
to the crown. 
Fig. 139. 
The soldering should be done from the outer surface of the crown 
and no investment is necessary. The proper relationship may be main- 
tained while soldering by the use of soldering tweezers as indicated in 
Fig- J39- The ordinary, straight-pointed automatic or spring soldering 
tweezers may be adapted to this purpose by simply bending one end at a 
right angle. 
The soldering should be done in a manner which will insure a flush 
joint between crown and backing when finished, and 20 karat solder 
should be used. The desired and required reinforcement of the cusps 
may be made after the backing has been soldered and as low as 18 karat 
solder may be used for this purpose. 
When the soldering has been completed, the facing should be placed 
in its position in the crown (Fig. 138 D) and its relationship sustained 
and secured by bending the projecting ends of the pins down close to the 
backing, from the inside of the crown. If the porcelain is well protected 
by the gold at the occlusal angle, this simple retention, if further fortified 
by cementing the facing to the backing before bending the pins, may 
meet all requirements. Facings used in this manner are replaceable easily 
in the event of fracture. 
But where the protection afforded by the gold is doubtful, or where 
greater strength in the attachment of the facing to the crown than is 
offered by the thinness of the pure gold backing is demanded, the pins 
may be soldered to the backing. 
In soldering the pins to the backing, either of two methods of pro- 
cedure may be followed: GOLD TELESCOPE CROWNS WITH PORCELAIN FACINGS 
163 
First: Crown and facing may be invested with a thin covering of 
soldering investment compound, heated to a high heat over the flame, 
primarily, and then soldered with 18 karat solder, using a small, pointed 
flame from the blowpipe. In this procedure just enough soldering in- 
vestment compound to protect the porcelain and the solder used pre- 
Fig. 140. 
viously, and to sustain the relationship, should be used. And the flame 
from the blowpipe must be small enough to penetrate the inside of the 
crown, and to reach the pins and solder. Such a procedure may be 
accomplished with ease, if the invested crown is heated previously to a 
red heat before attempting to solder. 
Second: A simpler method of investment consists of wrapping the 
crown and facing in asbestos paper and holding directly in the flame. 
(Fig. 140.) This method may be used successfully if the asbestos paper 
is folded over and covers the occlusal end of the crown well, and if the 
crown and facing are heated slowly and carefully. 
Silicate Cement Facings. 
The silicate cements, instead of porcelain facings, may be used as a 
means of avoiding the display of gold in the restoration of bicuspids and 
first molars. In the use of these vitreous products for this purpose, the 
crown may be made by any of the methods described. Definite marginal 
angles and a retentive shape should be given to the buccal surface. 164 
CROWN AND BRIDGEWORK 
When the crown has been finished and polished, the desired color of 
silicate cement should be selected, mixed properly and carefully adapted 
to the surface outlines. When crystallized, it should be polished with 
fine disks, and then kept moist until the crown is mounted. 
If the crown is to be used as an attachment for bridgework, the silicate 
facing should not be placed until the work is completed and finally pol- 
ished. Artistic results are possible, but permanency of color and of 
form is doubtful. 
Application to Anterior Teeth. 
The combination of gold telescoping crown with porcelain facing in- 
applicable also to the restoration of anterior teeth. In this application 
the type of construction embraces the features of an all-porcelain jacket 
crown, and differs only in the fact that the formation of a shoulder is 
unnecessary and the body of the restoration is made of gold. 
When a crown is to serve as a single unit restoration, only, a full 
all-porcelain jacket crown would be the more ideal restoration in all cases. 
But where pulp and tooth conservation are desirable, and where the 
restoration is to be used as an attachment for bridgework, thus demand- 
ing the use of gold for the purpose, or, in the absence of adequate, skilful 
technic, or of proper facilities for doing porcelain work, this type of 
construction often may be found useful. 
In the construction and application of this type of crown restoration, 
the formation of a gingival shoulder is unnecessary for the reason that 
gold, instead of porcelain, is used in obtaining adaptation to the root. 
Gold, when finished down to a thin, attenuated edge, is not friable, hence 
a thin, overlapping, or telescoping joint may obtain in the use of gold, 
which would not be practicable in the use of porcelain alone. 
Since the strength of the crown, even though it is made with gold 
in combination with a porcelain facing, must obtain at the expense of the 
supporting natural crown, it is necessary that a preparation of the re- 
maining natural crown which will be favorable to the possibilities of 
strength in the restoration, must be made. 
This means that the supporting natural crown must be sacrificed to 
an extent which will insure adequate inherent strength in the restoration, 
and to an extent often exceeding the requirements for a full porcelain 
jacket crown restoration as a single unit. The increased requirements 
in this connection are illustrated in Fig. 141 A.* 
Construction. The type of construction which is productive of the GOLD TELESCOPE CROWNS WITH PORCELAIN FACINGS 
165 
best results in the application of gold telescope crowns in combination 
with porcelain facings, for the anterior teeth, is obtainable first, by taking 
a single unit impression of the remaining natural crown in hard impression 
compound and making an amalgam cast. 
Coping. When the cast has been obtained, a coping of pure gold, 
36 gage, should be adapted to it. This should be done previous to any of 
the following details of technic. A measurement of the circumference of 
A 
B 
C 
D 
Fig. 141. 
the tooth then should be obtained and a narrow band made, using 22 karat 
gold plate about 30 gage in thickness. The band should be trimmed to 
follow the gingival curvature, and, when so trimmed, should be adapted 
to the tooth. 
When this adaptation has been completed, the thin, pure gold coping, 
which has been made previously, should be placed in position on the tooth, 
and the narrow band then forced over it and into position. The relation 
between coping and band should be sustained with wax, or temporary 
stopping, and the two removed. The interior of the band and coping 
should be filled with just enough soldering investment compound to sustain 
their relationship while soldering. 
When the investment compound has crystallized, the wax, or tem- 
porary stopping, should be warmed and removed carefully. The band 
and coping, then, should be united with 22 karat solder. In uniting them, 
the lingual surface may be reinforced with solder sufficiently to insure a 
retention of form and shape. But the labial surface should remain thin 
in order to accommodate the subsequent adjustment of the facing. 
The coping, now, should be fitted finally to the supporting tooth and 
all requirements of adaptation perfected. The band around the labial 
gingiva may be allowed to remain as wide, or as narrow, as the require- 
ments may seem to indicate; or it may be cut away entirely at this point. 
The remaining details of construction may be secured best by the in- 
direct method. When the final requirements of adaptation of the coping 
have been completed, it should be placed in position on the tooth, and 
the bite and impression taken. 166 
CROWN AND BRIDGEWORK 
A bite may, or may not, be necessary in anterior crown restorations, 
but it is always safest to have this guide and to be fortified with the 
assurance of a correct relationship of the opposing teeth. 
The impression should be taken with plaster. When the impression 
has been varnished, and just previous to pouring the cast, the interior 
of the coping should be painted with melted wax. This precaution per- 
mits of its subsequent detachment from the cast without danger of dis- 
torting its shape. The cast now should be poured with plaster. 
When the casts have been obtained, the coping should be warmed 
over a flame and detached carefully; then cleaned in the acid bath and 
replaced. 
The porcelain facing then should be selected. The replaceable type 
should be used, if possible, but the required thinness may demand the 
use of a long-pin facing. Where a replaceable facing may be used, it 
should be placed in position on its backing and the two then ground to 
the desired adaptation. When this has been secured the relationship 
should be sustained with wax, the facing removed, and the crown detached 
from the cast. 
The completion of the crown may be accomplished either by casting 
or soldering as the requirements may indicate. Where some opportunity 
for contouring the lingual surface, and where some little thickness of 
wax presents, casting produces the best results. But if extreme thinness 
is demanded, soldering may be preferable, or may be necessary. 
Replaceable Facings. In the use of replaceable facings, where the 
crown is to be completed by soldering, the backing should be extended to 
cover the gingival end of the porcelain, as a means of obtaining a more 
sanitary and more finished result. 
Such extensions are secured readily and easily by tacking a small 
piece of platinum foil, i-iooo in thickness (or pure gold 36 gage) to 
the backing with a small bit of solder. After being attached, thus, to 
the backing, this extension then may be burnished closely to the neck of 
the facing and all surplus trimmed away until a continuous backing 
presents. 
Flat-back Facings. The ordinary long-pin facings may be used suc- 
cessfully also. Those of the long, thin-neck variety are adapted especially 
for this purpose. (Fig. 141 B.) In their use the selection and the subse- 
quent adaptation should be made with care. When the desired adaptation 
has been obtained (Fig. 141 C), the facing should be backed with pure 
gold, 36 gage. (Fig. 141 D.) Then it may be attached to the coping by 
means of casting or of soldering. GOLD TELESCOPE CROWNS WITH PORCELAIN FACINGS 
167 
Casting. When the crown is to be completed by casting, the facing 
and backing should be placed in their proper relation to the coping and the 
desired contour made with casting wax. This completed, the facing 
should be detached from its backing and small graphite pins then inserted 
into and to the full depths of the holes made and left in the wax by the 
pins. Pocket pencil leads answer this purpose nicely and the use of these 
graphite pins reserves accommodation for the pins of the facing after the 
casting is made. Afterward, they may be removed from the casting by 
boiling in dilute hydrochloric or sulphuric acid. When this procedure is 
followed it is well, also, to lubricate the projecting ends of the pins as a 
means of facilitating their subsequent detachment from the wax. 
When the crown has been cast, and the graphite pins have been re- 
moved from the holes, the facing should be adjusted to position and 
finally cemented. Threading the pins with a small tap, which is made 
for this purpose, affords increased strength in the attachment of the facing 
with cement. 
Soldering. Where the crown is to be completed by soldering, the same 
procedure may be followed to good advantage in all cases where the pins 
may be allowed to remain their full length. All of the advantages to be 
obtained by cementing the facing present. But in cases where the pins 
must be shortened in order to effect the desired adaptation of the facing to 
the coping, soldering may be indicated. 
Where the attachment of the facing by soldering is indicated, the pins 
should be bent over upon the backing, and the crown then invested, heated 
carefully and, finally, soldered. CHAPTER XII. 
DOWEL CROWNS. 
The telescoping method of attachment permits pulp conservation, 
and of the conservation of the remaining natural tooth crown. The dowel 
method of attachment is applicable to pulpless teeth only, and requires the 
removal of the remaining natural crown to the gingival line. 
Wherever the pulp must be devitalized, or where it has been devital- 
ized ; wherever the pulp-canal must be filled, or where it has been filled; 
wherever the remaining natural tooth crown must be sacrificed to the 
gingival line, or where it may have been thus sacrificed previously; and 
where the esthetic requirements demand a porcelain restoration of the 
lost natural crown, some type of dowel crown is indicated as a means 
of insuring stability and permanency in the attachment of the restoration 
to the supporting root. 
This type of crown restoration was designated formerly as a “pivot” 
tooth, and, later, as a “Richmond” crown. It is applicable to the restora- 
tion of the crowns of all teeth within the range of vision, and much versa- 
tility in the methods and technical details of construction has been dis- 
played. 
Dowel. The use of a dowel is the mechanical means of obtaining 
resistance to stress and of insuring strength and stability in the attachment 
of the crown to its supporting root. Accommodation for the dowel is made 
by enlarging the pulp canals. 
Coping. A coping may or may not be used. Accuracy of adapta- 
tion of the crown restoration both to the periphery and to the basal end 
of the supporting root, however, is increased and insured by the use of a 
coping. And in proportion as accuracy of adaptation of the basal end of 
the crown to its supporting root is obtained, protection of the root against 
the influence of caries and against the possibilities of fracture also will 
be secured. And permanency in the restoration will be increased corre- 
spondingly. 
It is in the direction of making and adapting the coping that the great- 
est versatility has been exhibited. Full bands encompassing the entire 
168 DOWEL CROWNS 
169 
circumference of the root are used. Partial bands adapted to all surfaces, 
except the labial or buccal, are used. And copings adapted to the basal 
end only, and without any band whatever, are used. 
These variations all have a place of usefulness, and the requirements of 
root protection and of dowel crown construction are so varying that no 
one method of procedure nor any one type of construction is applicable 
universally to all cases. Success, therefore, will depend upon the exercise 
of judgment in the choice of that method which seems best adapted to 
the requirements of the individual case. 
Requirements. The requirements incident to the application and con- 
struction of dowel crowns may be considered from three viewpoints : physi- 
ological, mechanical and esthetic. 
Physiological.—As pulp devitalization, pulp removal and root-canal fill- 
ing are necessary, and since the health of the supporting root and of its 
investing tissues, and, hence, the success and permanency of the crown 
restoration, are to depend entirely upon the successful execution of these 
procedures, it is evident that the requirements in this connection must be 
met properly and to the fullest extent. 
Radiographic evidence that no eradicable infection presents, that 
health obtains, and that the root canals are filled well, always should precede 
all mechanical efforts in the direction of restoration. 
In addition to the requirements pertaining to the conservation and main- 
tenance of health, the restoration of function must be considered because 
health will not be maintained unless normal functional activity in all direc- 
tions is restored. 
A restoration of normal functional activity demands that the physiologi- 
cal requirements of alinement, approximal contact and occlusion be sat- 
isfied always—and carefully. 
Mechanical. Following an observation of the physiological require- 
ments, maintenance of the health of the investing tissues will depend 
largely upon the absence of gingival irritation, and the absence of the 
latter will depend entirely upon accuracy of adaptation in the relationship 
existing between the supporting root and the crown restoration. 
Hence, in the adaptation of the crown to the supporting root, with or 
without a coping, the adaptation must be made in such manner and with 
such accuracy as to preclude, or, at least, minimize the possibilities of 
mechanical irritation. This applies in all cases, whether a coping is used 
or not, or whether a full band, a partial band, or no band at all is in- 
volved. 
An observation of this requirement means: First: the supporting root 170 
CROWN AND BRIDGEWORK 
must be prepared properly to receive whatever type of coping, or of 
crown, is indicated and is to be used; and, second: an accurate adaptation 
of the crown, both to the periphery and the basal end of the root, must 
exist always. The success of the restoration, from a mechanical view- 
point, depends entirely on a strict adherence to these procedures. 
Esthetics. An observation of the requirements of esthetics is made 
possible by the use of porcelain. An ambition to develop an eye for 
Fig. 142, 
color and for form, an appreciation and a recognition of Nature’s great 
law of harmony and an effort to simulate existing environmental condi- 
tions, are all essential to the achievement of the highest possibilities in the 
use of porcelain, and in the construction of dowel crowns. 
Color. In the selection of porcelain teeth or facings which are to be 
used in the restoration of the crowns of all teeth within the range of 
vision, it is essential to exercise the greatest care in matching the color 
of the natural crowns of the adjacent teeth. 
The selection must be made with a view to insuring a finished restora- 
tion that will match the crowns of the adjacent teeth so closely in color that 
it will not be conspicuous. If the color cannot be matched perfectly, or 
even closely, a shade darker, rather than a shade lighter, always should be 
used. 
Type. To obtain an expression of harmony in the restoration, the se- 
lection of the porcelain tooth or facing to be used should be made al- 
ways with a view to simulating the form or type of the crowns of the 
adjacent natural teeth. In this connection it is especially necessary that 
the type of tooth selected should simulate closely the type of the crown 
of the corresponding tooth on the opposite side of the arch. Thus, a cen- 
tral incisor should resemble its mate closely in type. A lateral incisor 
should correspond in type with its mate, the opposite lateral incisor, and 
a cuspid likewise, should correspond with the cuspid present. DOWEL CROWNS 
171 
Harmony. Color and type constitute two expressions of harmony. In 
restorations involving the six anterior teeth, however, further expressions 
of harmony are to be obtained by simulating closely the incisal edge, in- 
cisal angles, abrasions, erosions and discolorations of the adjacent teeth, 
or of the corresponding natural tooth crown. 
Display of Gold. Any unnecessary display of gold is always objec- 
tionable. But in cases where the natural crowns of the adjacent teeth are 
filled freely with gold, and where the restoration would be the only tooth 
not so defaced, and therefore conspicuous because of its perfection, the 
insertion of small gold fillings, in the restoration, may add a further and 
desirable expression of harmony by simulating more closely the environ- 
mental conditions. 
The display of gold at the gingival line, however, is objectionable and 
should be avoided always. A display of gold at this point is a common 
fault in the construction of dowel crowns with full peripheral bands. 
This fault is to be overcome by making the band narrower and by ob- 
serving the proper gingival curvature of the band and facing, in the con- 
struction of the restoration. (Fig. 142.) 
Methods of Construction. 
In the construction of dowel crowns several methods of procedure are 
followed. These methods involve, primarily, the construction of a sup- 
porting coping, of which the dowel becomes an integral part. 
Construction of Coping. In the construction of the coping, the 
variations of the construction are the use of a full peripheral band, a par- 
tial band only, and of no band at all. And, both the direct and the indi- 
rect methods of construction are applicable to all types. 
Copings with Full Peripheral Bands. 
The construction of copings involving a full peripheral band may be 
made successfully either by the direct or the indirect method. This type 
of construction is indicated most generally in cases where the crown is to 
serve as an attachment for bridgework. 
Direct Method. In the application of the direct method of construc- 
tion, a wire measurement of the circumference of the root at the gingival 
line is taken with measurement wire. A narrow band is made, using 22 
karat gold plate, 28 or 29 gage, cut to the exact length (Fig. 143) and 
soldered with 22 karat solder. 172 
CROWN AND BRIDGEWORK 
The band is purposely made much wider than necessary, in order 
that it may be trimmed to follow the gingival curvature evenly and to fa- 
cilitate fitting. It is then conformed to the general outline of the root, 
trimmed to accommodate the gingival curvature, and gently forced to place 
upon the root until the edge passes just within the free gingival margin 
Fig. 143. 
Fig. 144. 
uniformly. It is then removed and the surplus edge cut away until the 
desired width obtains. 
Full peripheral bands for dowel crowns are used only for the purpose 
of protecting the supporting root more adequately against the possibility 
of fracture, and of obtaining a maximum of strength in the attachment 
of the restoration, and a maximum of protection to the cement to be used 
in mounting. 
The band around the labial or buccal surface of the root should be 
only wide enough to afford these features, and to admit of placing the gin- 
gival edge of the porcelain tooth, or facing in close proximity to the gin- 
gival tissues. It may and should be wider upon tbe mesial, distal and 
lingual surfaces. Its width, however, must be governed by the shape 
given to the basal end of the root (Fig. 144 A), and the edge must be 
trimmed to approximate this surface of the root evenly at all points. 
(Fig. 144 B.) 
When thus trimmed, it may be removed, using a small, pointed instru- 
ment for the purpose. A floor now should be soldered to this edge 
of the band. While the same thickness and karat of gold used for the 
band may be used for the floor, it is desirable to use a thinner gage in 
order to admit of placing the porcelain tooth, or facing, in closer relation- 
ship with the gingival tissues. Hence, 32 gage, 22 karat gold, or 36 
gage platinum should be used. Platinum of thinner gage than gold DOWEL CROWNS 
173 
may be used because of its higher fusibility. No special degree of 
strength is needed in the metal used for the floor because it is to be rein- 
forced adequately later. 
In soldering the floor to the band, a liberal surplus of the floor metal 
will facilitate the procedure, and only sufficient solder of 22 karat or 20 
Fig. 145- 
Fig. 146. 
karat to unite floor and band should be used. The soldering may be ac- 
complished by holding the parts directly in the flame as indicated in Fig. 
145- 
When band and floor have been united thus, the surplus should be 
trimmed away and the coping then finished to the point of polishing. 
Reinforced Bands. Greater strength and better formation of the 
gingival outline of the completed restoration will be obtained by rein- 
forcing the mesial, distal and lingual surfaces of the band. This rein- 
forcement may be accomplished easily by allowing a slight surplus of the 
floor to extend from the band upon these surfaces, painting the interior 
of the coping with whiting, and then forming the desired reinforcement 
with 22 karat solder. (Fig. 146.) 174 
CROWN AND BRTDGEWORK 
The use of whiting painted on the inside of the coping prevents refus- 
ing the solder previously used in uniting band and floor. It also prevents 
the solder from flowing to the inside of the coping. 
Fig. 147. 
Coping with Partial Bands. 
In many cases a full peripheral band is both unnecessary and objec- 
tionable. It is unnecessary because all of the advantages of a full band 
may be obtained by the use of a partial band. And it is objectionable 
because the normal condition of the labial or buccal gingiva is disturbed, 
recession of these tissues is invited, and some display of gold is unavoid- 
able. 
In the application of dowel crowns to the ten anterior teeth, therefore, 
if the use of a band is indicated at all, a partial band, adapted to all sur- 
faces except the labial or buccal meets all requirements, eliminates some 
objectionable features, and affords the most favorable type of construction. 
Copings which involve the application of a partial band only may be 
constructed either by the direct or the indirect method. 
Direct Method. In the application of the direct method, the best 
results are obtained by making and fitting a full band, primarily, and 
attaching the floor to it in exactly the same manner indicated previously, 
except that the floor is not soldered to the band along the labial or buccal 
edge. 
To prevent the floor from becoming attached to the band at this point, 
the edge of the band may be painted with whiting, or other suitable anti- 
flux, or a piece of very thin mica may be inserted between band and floor 
at the desired point. (Fig. 147 A.) 
The floor then should be soldered to the remaining edge of the band 
and the desired reinforcement made, after which the labial or buccal 
surface of the band may be cut away to the desired pofnt. (Fig. 147 B.) 
This unsupported edge of the floor finally may be adapted directly to the DOWEL CROWNS 
175 
root, and a well-adapted coping having a partial band, only, obtains. 
(Fig. 147 C.) 
Burnishing. Another and simpler method of constructing a coping 
having a partial band is by burnishing the coping to the desired form and 
outline directly upon the root. Burnishing, however, while a simple pro- 
Fig. 148. 
cedure when soft metals of thin gage are used, is not always productive 
of accuracy. It is always difficult and uncertain because of the attending 
discomfort. 
Where a coping with a partial band is to be constructed by burnishing, 
a piece of thin platinum, or pure gold, about 36 gage, should be cut some- 
what larger than the size of the root. Gold, being the softer metal, is 
adapted more readily by burnishing, and the best results, therefore, are 
obtained from its use. The piece should be annealed, placed in position 
upon the root, held in place firmly and burnished carefully to the basal end, 
using blunt instruments. When the outline of the end of the root is well 
defined in the surface of the gold, the surplus around the labial or buccal 
edge should be trimmed away entirely. Only enough surplus to form the 
partial band should be permitted to remain around the mesial, distal and 
lingual surfaces. This surplus then should be slit in the center of the lin- 
gual surface and at one or more other favorable points. It then may be 
replaced upon the root and the flaps formed by slitting, bent over upon 
and burnished closely to these surfaces of the root. When the desired ac- 
curacy of adaptation has been secured, the slits may be filled with 22 
karat solder, and the coping completed. (Fig. 148.) 
Coping without Band. 
A coping having no peripheral band whatever, and yet well adapted 
both to the basal end and to the periphery of the root, is the least irri- 
tating and the most ideal construction. 176 
CROWN AND BRIDGEWORK 
Where the crown is to serve as a means of affording attachment for 
bridgework, the use of a partial band, and, in some instances, the use of 
a full band, is advantageous, and, perhaps, necessary. But, where the 
crown is to serve merely as a single unit restoration, the use of any form 
of band is unnecessary in a very large proportion of cases, provided that 
the coping is well adapted both to the basal end and to the periphery of its 
supporting root. 
Direct Method. The adaptation of coping without a band may be 
obtained with some degree of accuracy by means of the direct method, or 
by burnishing directly upon the tooth. Platinum or pure gold of about 36 
Fig. 149. 
gage should be used. The same detail of procedure indicated for partial 
bands should be followed with the same relative advantages of platinum 
over pure gold. (Fig. 149.) More accurate results and less discomfort, 
however, are to be obtained, always, from the indirect method, and from 
swaging instead of burnishing. 
Indirect Method. In the construction of copings by the indirect 
method, greater simplicity in the technical details of procedure and in- 
creased accuracy of adaptation both to the periphery and to the basal 
end of the root obtain. These features may be secured by taking a single 
unit impression of the root-end, making an amalgam cast, and swaging 
the coping in one single piece. 
The additional time required in this method is compensated for by the 
increased accuracy of adaptation. And this advantage is combined with 
the further advantage of making a coping which may embrace and include 
a full band—any part of a band, or no band at all—as the requirements 
of the case or the preference as to type of construction may indicate. 
In the application of the indirect method, a free exposure of the root- 
end is absolutely necessary. If the root-end is not exposed freely, the 
gingival tissue should be packed away first, until a favorable exposure is 
obtained. This may be accomplished by mounting some type of temporary 
crown previously, or by packing temporary stopping tight over the root- 
end. DOWEL CROWNS 
177 
A unit impression band of a size which will pass just freely over the 
root-end, should be selected and trimmed to meet the gingival curvature 
evenly upon all surfaces. An impression of the root-end should be taken 
with impression compound. (Fig. 150 A.) The impression then should be 
invested in plaster in such manner as to form a matrix for the body of 
the amalgam cast. When the plaster has crystallized, the matrix should 
Fig. 150. 
Fig. 151. 
be trimmed until all surfaces of the imbedded impression are exposed 
freely. (Fig. 150 B.) The amalgam cast now should be made. 
When the cast has been obtained (Fig. 150 C) it should be mounted in 
impression compound in a metal ring, such as constitutes a part of various 
swaging and moldine outfits. The ring of a casting flask will answer the 
purpose. (Fig. 151 A.) 
Platinum or pure gold, 36 gage, should be conformed to the surface 
outlines of the amalgam cast by swaging or burnishing. (Fig. 151 B.) 
During the process of swaging or burnishing, the metal should be annealed 
often, and the surplus trimmed away gradually until the adaptation and 
the desired outlines are obtained. 178 
CROWN AND BRIDGEWORK 
The use of a thin gage of metal facilitates the adaptation, and while 
pure gold is adapted with more ease, the use of platinum is preferable 
because of its greater resistance and higher fusibility. The greater resis- 
tance of platinum insures the retention of its given form and shape, and 
its higher fusibility eliminates the possibility of subsequent fusing in the 
final assemblage of the crown. The use of platinum, therefore, will afford 
the best and most reliable results when the coping is constructed by the 
indirect method. 
Dowels. 
When the coping is completed by any of the preceding methods, it 
should be placed in position on its supporting root and the dowel fitted 
and subsequently soldered to it. A dowel embracing all requirements for 
the individual case then should be made. 
In enlarging the pulp canal to receive and accommodate the dowel, it 
should be noted that the enlargement of the canal at is orifice in the basal 
end of the root is made at the expense of the lingual area, mainly, or, 
perhaps, entirely. An observation of this precaution carries the end of 
the dowel to a point where it will accommodate the proper and desired re- 
lationship of the porcelain tooth or facing to be used with the coping when 
it is attached to, and becomes an integral part of the restoration subse- 
quently. 
The importance of observing this precaution at this time must not be 
underestimated. And, in order to obtain the desired relationship between 
the coping, the dowel and the porcelain tooth or facing to be used, the 
porcelain tooth or facing should be selected previously. When the pulp 
canal is enlarged thus to receive and accommodate the dowel, the coping 
should be placed in position on the root and the floor perforated. The 
perforation should be made of such size as to fit the dowel closely, and 
should be placed at a point which will receive and sustain the dowel in 
its proper relationship. 
If by any mishap the perforation should be made too large to afford 
contact with the dowel around its entire circumference, another and a 
smaller piece of gold or platinum may be perforated properly and bur- 
nished to a close adaptation to dowel and floor, thus restoring contact and 
facilitating soldering. This supplementary piece will become a part of the 
coping at the time of soldering the dowel. 
When the desired relationship has been obtained, it should be sus- DOWEL CROWNS 
179 
tained temporarily (Fig. 152 A) and coping and dowel then removed 
carefully and invested and soldered. Adhesive wax, base-plate wax, or 
temporary stopping answer this purpose nicely, and either may be re- 
moved easily after investment. An investment compound which crys- 
tallizes should be used and a larger quantity than just sufficient to sustain 
the relationship while soldering (Fig. 152 B) is unnecessary. 
Dowels in Multi-rooted Teeth. In the construction of copings for 
multi-rooted teeth, one dowel is all that will be required, provided it en- 
Fig. 152. 
Fig. 153. 
gages the canal to a sufficient depth, and provided that it is proportionate 
in diameter with the requirements of strength. Where these two features 
may not be observed without endangering the strength of the root un- 
necessarily, more than one dowel may be used. Where more than one 
dowel is used, they may be made shorter in length and smaller in diameter. 
In upper first bicuspids, if one dowel will meet the requirements, it 
should be placed in the lingual canal in order that its surplus end may 
offer no obstruction to the placement of the porcelain tooth or facing in 
its desired relationship. If two dowels are necessary, care must be exer- 
cised not to weaken the root unnecessarily in the enlargement of the 
canals to receive the dowels. (Fig. 153.) 
The same precautions and the same care must be observed with molar 
roots. CROWN AND BRIDGEWORK 
180 
Application of Porcelain Teeth or Facings. 
When the coping has been constructed and adapted by any of the pre- 
ceding methods, the porcelain tooth or facing to be used should be se- 
lected. The selection of the tooth or facing is an important detail and 
should be made even before the completion of the coping in most cases, 
for the reason that some special technic is most applicable, usually, to the 
particular type of tooth or facing used. 
The esthetic requirements of dowel crown construction may be met by 
the use of two different types, full porcelain crowns and simple facings. 
Use of Full Porcelain Crowns. 
Full porcelain crowns are applicable in the construction of dowel 
crowns in all cases where the requirements of occlusion will admit their 
use without extensive grinding. When a selection may be made which 
will not require extensive grinding, this type of porcelain tooth will pos- 
sess strength adequate to the requirements in most cases. But where 
extensive grinding becomes necessary, the strength of the porcelain is 
diminished accordingly, and may be diminished to a degree which will 
contraindicate the use of an all-porcelain crown and demand the greater 
indestructibility obtainable by the use of a simple facing only. 
Advantages. Where full porcelain crowns may be used, better form, 
better color and higher esthetic possibilities constitute the chief advantages. 
In the restoration of the crowns of the six anterior teeth, gold backings 
are avoided; hence, greater translucency, and, therefore, better color is 
assured. And, in the restoration of crowns of posterior teeth, the use 
of all-porcelain crowns insures better form and greater masticatory effi- 
ciency than may be obtained by the use of simple facings in combination 
with gold. 
When these advantages are to be combined with the further advantage 
which is obtainable from cementing the porcelain to its supporting basic 
structure, and from making and retaining duplicates at the time of con- 
struction, the highest possibilities of dowel crown restorations are 
achieved. 
Any of the all-porcelain crowns not having dowels as an integral part 
may be used. The Goslee tooth was designed especially to meet all of the 
requirements of dowel crown restorations without grinding. But any of 
the all-porcelain crowns without attached dowels may be used to advan- DOWEL CROWNS 
181 
tage, and successfully, by grinding the basal end to simulate the general 
form and outlines of the original Goslee tooth. (Fig. 154.) 
Application. In the construction of dowel crowns in which this type 
of all-porcelain tooth is used, the adjustment of the tooth to the coping 
is accomplished best by making it directly upon the supporting tooth in 
the mouth, and by doing this before the dowel is soldered to the coping. 
Fig. 154. 
Direct Method. The tooth to be used should be selected when the 
coping has been made and adapted. Then it should be ground to meet 
all requirements of gingival curvature, contact, alinement and occlusion. 
When these requirements have been met, the coping should be placed 
in position on the root and perforated to receive the dowel. The dowel 
now should be adjusted to the root in such manner as to sustain the proper 
and desired relationship between coping and tooth. When this has been 
done the adjustment ot the dowel to the coping should be sustained with 
melted wax. Dowel and coping now should be detached from the root, 
invested, as indicated previously, and then soldered. (Fig. 155 A.) A 
small bit of solder only should be used because any unnecessary surplus 182 
CROWN AND BRIDGEWORK 
might interfere with the adjustment of the porcelain tooth to the coping 
after soldering. 
Up to this point the coping fits the root but does not fit the tooth. 
Adaptation to the basal end of the porcelain tooth, together with adequate 
Fig. 155 
Fig. 156. 
reinforcement of the coping must then be secured. These may be accom- 
plished by casting or by soldering. 
Casting. 
The casting method offers the best and simplest means of completing 
the coping. When it is to be used, the final adjustment of the porcelain 
tooth to the coping should be made with casting wax, and the best re- 
sults are obtained by making the adjustment directly in the mouth. 
To accomplish this step of the procedure in the best and most simplest 
manner, a small bit of soft casting wax should be melted upon the surface 
of the coping first, and the coping placed in position on the root. The 
basal end of the porcelain tooth now should be lubricated with oil and the 
tooth forced to place in its relation to the coping. The soft wax admits 
of and sustains this relationship. 
Tooth and coping now should be detached from the root carefully, 
and the space between them filled with melted casting wax until com- 
pletely filled and until the desired contour is obtained. (Fig. 155 B.) DOWEL CROWNS 
183 
The use of a hard casting wax is advantageous for this purpose be- 
cause retention of shape and form is necessary. When the desired shape 
and form obtain, the porcelain tooth should be detached carefully from 
the wax, then replaced, and the sprue-former attached securely where 
the wax is thickest. (Fig. 156 A.) The porcelain tooth now should be 
removed and the investment and casting made. 
Fig. 157. 
A high grade gold alloy should be used in making the casting, and 22 
karat is preferable. When the casting has been made (Fig. 156 B), the 
surplus should be cut away, the base cleaned in acid and then finished, and 
the porcelain tooth cemented to place. A physical union between pure 
gold coping and casting may result; but, if it does not result, a small bit 
of 22 karat or of 20 karat solder may be used. 
Soldering. 
When it is desirable to complete the construction of the coping by 
soldering, instead of by casting, a backing of pure gold (36 gage) must 
be adapted to the basal end of the porcelain crown previous to the final 
adjustment of the tooth to the coping. 
The adaptation of the backing to the porcelain crown may be made 
by burnishing, and a slight surplus of the backing should be allowed to re- 
main and to lap over upon the porcelain until after the soldering has been 
completed. (Fig. 157 A.) 
When the porcelain crown has been backed with pure gold in this 
manner, the backing should be perforated immediately over the hole in the 
crown, and the relationship between the crown and its backing and the 
coping then obtained. (Fig. 157 B.) This relationship may be sustained 
with soft base-plate wax. Crown and coping now should be detached 
from the root, the space between coping and backing filled with melted 
wax, and the crown removed. 
Coping and backing then should be invested, using enough investment 
only to sustain their relationship securely. When the investment has 184 
CROWN AND BRIDGEWORK 
crystallized, the wax should be removed with boiling water, the surfaces 
of metal fluxed, and the case placed over the flame and heated to a high 
temperature. The space between coping and backing then should be filled 
completely and to the desired contour with 22 karat or 20 karat solder. 
The base, thus completed, should be cleaned in acid, the porcelain crown 
cemented to place, and the crown finished and polished. 
Fig. 158. 
Indirect Method. 
The indirect method is applicable to the construction of crowns of this 
type, but does not afford the same opportunities for alining and adjusting 
the crown and the dowel to the root with quite the same degree of ac- 
curacy and facility. 
Where it may be desirable to use the indirect method, the adjustment 
of the dowel to the coping and to the crown must be made directly upon 
the root. When this adjustment has been secured, and when the dowel 
has been soldered to the coping, the indirect method may be followed 
successfully in the completion of the crown. 
This procedure consists in taking the bite in wax and the impression in 
plaster, with the completed coping in position on the root. The coping, 
usually, will be removed with the impression, but its correct relationship 
must be insured. The exposed surfaces of coping and dowel then should 
be painted with melted wax as a means of insuring removal from and ac- 
curate replacement upon the cast. The impression should be varnished 
and the cast poured in plaster. When the cast has been obtained and 
mounted upon the articulator, the coping should be warmed, detached, 
cleaned in acid, and then replaced upon the cast. 
The remaining details of construction may be carried out, as indicated, 
and the coping may be completed either by casting or soldering. (Fig. 158.) 
Use of Porcelain Facings. 
The use of porcelain facings, instead of all-porcelain crowns, in the 
construction of dowel crowns, produces results that do not subscribe to DOWEL CROWNS 
185 
the esthetic requirements to the same degree, but greater indestructibility 
may often be obtained: First, from constructing the body of the crown 
with gold; and, second, from protecting the thin porcelain facing in 
proper manner. 
Fig. 159. 
Two types of porcelain facings are used. These are known as “re- 
movable and replaceable” facings, and “flat-back” facings. 
Indications. The use of thin porcelain facings of some type is in- 
dicated in all cases where the occlusion and the requirements of stress 
demand greater indestructibility than is possessed by an all-porcelain 
crown. 
Removable and Replaceable Facings. 
Every advantage obtainable from the use of porcelain facings is 
secured in the best manner by the use of replaceable facings. 
In the use of facings of this type, the porcelain is not subjected to the 
heat of soldering; its attachment to the supporting structure being cush- 
ioned by cement is less rigid, and, therefore, it is less likely to be frac- 
tured ; duplicates may be made at the same time; every opportunity for re- 
placement presents, and special backings are made for them. 
The type known as Steele’s Replaceable Facings are used generally. 
These are made in thin veneer facings for the six anterior teeth. (Fig. 
159 A.) A different type of bicuspids and molars presents an occlusal sur- 
face of porcelain. But the posterior teeth are adapted better to the re- 
quirements of a pontic for bridge work, than they are to the construc- 
tion of crown restorations. 186 
CROWN AND BRIDGEWORK 
Special backings made of gold alloy and also of a base metal alloy 
which will withstand high grade solders, or casting, are made for use 
with these facings. (Fig. 159 B.) The time required for making a back- 
ing, therefore, is saved. Backings made of gold alloy are preferable. 
Fig. 159. 
Fig. 159. 
Application. For the reason that the adjustment of the facing and 
its backing to the coping is made in the best manner when casts are used, 
the application of replaceable facings to the construction of dowel crowns 
is best secured by the use of the indirect method in all cases. 
Indirect Method. In the application of the indirect method, the 
coping should be made and completed, and the dowel soldered to it. The 
bite and impression then should be taken with the coping in position on the 
root. Care should be taken in ascertaining that the coping is in its cor- 
rect position in the impression and provision made for facilitating the de- 
tachment and removal of the coping from the cast, by painting it with 
melted wax previous to pouring the cast. 
The cast then should be made of plaster and mounted upon the ar- 
ticulator. When the coping has been detached, cleaned in the acid bath 
and replaced upon the cast, the facing should be selected and ground to fit 
the coping at the gingival edge closely, and to meet all other requirements. 
The backing then should be placed upon the facing and adapted to the 
coping. In order to insure a good, close joint between backing and coping, 
the edge of the backing must come in direct contact with the coping. DOWEL CROWNS 
187 
If direct contact is secured, the joint between the porcelain facing and 
the coping will be close in proportion as it may have been ground to fit 
closely. This will be close enough to insure a joint which will in most 
cases be more or less invisible when the facing is mounted with cement. 
But, where direct contact between backing and coping is not secured, 
the backing must be extended. Such an extension frequently is necessary, 
Fig. 159. 
and may be made easily. When the backing has been trimmed to the re- 
quired adaptation to all other surfaces of the facing (Fig. 159 C) a small 
piece of thin, pure gold (36 gage), or of platinum foil (1-1000) should 
be tacked to the backing with a tiny bit of solder. When tacked with 
solder, the extension should he burnished to a close adaptation to the 
porcelain facing and all surplus trimmed away. (Fig. 159 D.) 
In trimming away the surplus, the backing should be finished close 
to the mesial and distal edges of the facing; but it is always well to leave 
a slight surplus projecting beyond the facing upon the incisal end. It is 
well also to reinforce the incisal end of the backing with clasp metal. 
This reinforced surplus when finished down to the porcelain, after the fac- 
ing is mounted with cement, will insure a better protection to the porcelain 
than will obtain if finished close before cementation. (Fig. 159 E.) 
Facing and backing now should be placed in proper position on the 
coping and their relationship sustained securely with melted wax. If the 
construction is to be completed by the casting process, hard casting wax 
should be used. When the final construction is to be completed by solder- 
ing, adhesive wax should be used. 
When the desired relationship has been sustained in this manner, the 
crown should be removed from the cast, and the facing detached carefully. 
Then it should be invested in accordance with the requirements of cast- 
ing, or of soldering, as indicated. If to be completed by soldering, the 
investment should be made as illustrated in (Fig. 159 F). When com- 188 
CROWN AND BRTDGEWORK 
pleted by either method, the facing should be cemented to place, and the 
crown then finished and polished. (Fig. 159 G.) 
In the cementation of the facing, a cement of similar color always 
should be used. 
Fig. 159. 
Duplicate Replaceable Teeth and Facings. 
In the use of replaceable facings, a feature of advantage and import- 
ance results from the making of duplicates at the time of construction. In 
observing this procedure, the duplicate tooth, or facing, should be ground 
to the proper and required adaptation to the crown just previous to 
cementing the original. When thus ground and fitted, it should be placed 
in a convenient form of container, properly labeled and filed away; or, it 
may be given to and retained by the patient. 
Whenever duplicate teeth, or facings, are made, the mold number and 
the color used always should be a matter of permanent record. In the 
event of accident, replacement is facilitated. 
Use of Flat-Back Facings. 
Thin porcelain facings having platinum or platinum alloy pins baked 
in them are applicable also to the construction of dowel crowns. Facings 
of this type may be used in either one of two methods: 
First: They may be backed properly and attached to the coping by 
soldering or casting; or, second, they may be backed, removed from the 
backing while it is being assembled to the coping and attached to the com- 
pleted crown subsequently by means of cementation. And, if desirable, 
cementation may be supplemented by riveting the ends of the pins over 
upon the body of the finished crown. 
Because of the advantage to be obtained from the use of replaceable 
facings cemented to the basic structure, however; and because of the dan- DOWEL CROWNS 
189 
gers attending the soldering of porcelain facings, together with the weak- 
ening of the porcelain; and the elimination of opportunity for replacement 
in the event of fracture, this type of crown construction is not recom- 
mended for universal use. 
Application. When this type of facing is used in the construction 
of dowel crowns, its application can be made best by means of the indirect 
method. When the casts have been obtained and mounted upon the ar- 
Fig. 160. 
ticulator in accordance with an observation of all requirements previously 
mentioned, the facing should be selected and ground to the proper and de- 
sired adaptation. It then should be backed with gold. 
Backing. In backing flat-back facings, the incisal end should be 
ground until a sharp angle is produced. (Fig. 160.) The presentation of 
a sharp angle along this edge affords a definite finishing line for the back- 
ing, and a better protection for the porcelain in the finished crown. 
Pure gold, 36 gage, now should be cut somewhat larger than the 
size of the facing, annealed, perforated to accommodate the pins and burn- 
ished to a close adaptation to the facing. All surplus except a slight bit 
along the incisal end then should be trimmed away. Thin, pure gold is 
used because of the facility with which a close adaptation may be secured. 
In perforating the backing to engage the pins of the facing, care must 
be exercised in making the perforations. They must be of a size which 
will fit the diameter of the pins closely. When facings having short, 
sharp-pointed pins are used, the proper place for the holes may be located 
by placing the thin, pure gold backing on a pad of soft wood or heavy 
blotting paper, and pressing the pins entirely through the gold. Or, in the 
use of facings having pins with blunt ends, the ends of the pins may be 
pressed firmly against the gold as a means of locating the place for the 
perforations accurately, and a “plate-punch” then used. 
Casting. If the crown is to be completed by the casting process— 
casting directly to the porcelain—further reinforcement of the backing is 190 
CROWN AND BRIDGEWORK 
unnecessary; but close apposition of the backing to the facing should be 
secured and sustained. This is to be accomplished by bending the pins 
over upon it. 
Care should be exercised in bending the pins, and notching them at the 
desired point with a file, previously, will facilitate bending them. Facing 
and backing now should be placed in proper relation with the coping, the 
Fig. 161. 
Fig. 162. 
relationship sustained with casting wax (Fig. 161 A) and the crown 
removed from the cast. The contour desired now should be formed with 
casting wax (Fig. 161 B) the sprue-former attached securely, and the 
investment and casting completed. (Fig. 161 C.) 
If the case is heated to a high temperature before the casting is at- 
tempted, and if it is allowed to cool slowly after casting, the danger of 
fracturing the porcelain facing will be diminished. No advantages are 
obtained by casting directly to the porcelain, however, and, hence, it is a 
procedure which is unnecessarily dangerous. 
Soldering. When the construction of the crown is to be completed 
by soldering the facing to the coping, additional reinforcement of the 
thin, pure gold backing always should be made, previous to soldering. 
Reinforced Backings. Adequate and uniform reinforcement may 
be obtained easily by adapting a second backing made of 22 karat gold, 28 
gage or 30 gage in thickness to cover the thin, pure gold backing from 
and including the pins, to the incisal end. When the second piece of back- DOWEL CROWNS 
191 
ing has been adapted thus, the two backings should be united with solder. 
During the soldering, their proper relationship may be sustained by the 
use of automatic soldering pliers as indicated in Fig. 162. The backings 
should be united with 22 karat or 20 karat solder. After soldering, the 
backing should be placed in position upon the facing, (Fig. 163 A) and 
its relationship sustained by bending the pins (Fig. 163 B). All edges 
Fig. 163. 
Fig. 164. 
Fig. 165. 
of the backing then should be finished down close to the facing until no 
overhanging edges of gold present. (Fig. 163 C.) 
Facing and backing now should be placed in position on the coping, 
the relationship sustained with adhesive wax, the crown then removed from 
the cast, invested and soldered. (Fig. 164.) The soldering may be accom- 
plished easily by fluxing the surfaces of gold and heating the case thor- 
oughly before attempting to solder. And soldering may be accomplished 
with less danger of fracturing the porcelain facing than presents in cast- 
ing. 
The construction of a dowel crown involving a coping having a full 
peripheral band, the facing backed with a reinforced backing, and the 
crown completed by soldering is illustrated in Fig. 165. 192 
CROWN AND BRIDGEWORK 
The requirements of root preparation, the application of a coping 
having no peripheral band, and the crown completed by soldering are 
illustrated in Fig. 166. 
Fig. 166. 
Cementing and Riveting. 
Since no advantages are to be obtained either from casting or soldering 
directly to the facing, and since every advantage is to be gained by reliev- 
ing the porcelain facing from the influences of heating and cooling, and 
of expansion and contraction, there is but little, if any, excuse for using 
porcelain facings in this manner. 
The objectionable features are overcome, and all of the desirable fea- 
tures of a replaceable cemented facing gained by the use of flat-back fac- 
ings retained in their relationship to the basic structure: first, by means 
of cementation only; and, second, by means of riveting the surplus ends 
of the pins to the surface of the finished crown. 
In the use of flat-back facings which are to be sustained to the basic 
structure by cementing or by riveting, all the advantages of a replaceable 
facing may be secured, and are applicable to the construction of the crown, 
either by casting or by soldering. The “Lockit Cups” which are illus- 
trated in connection with the use of flat-back facings in the construction 
of posterior pontics for bridgework are useful. 
Casting. In this procedure, if the construction of the crown is to 
be carried through by the casting process, a single thickness of backing 
made of thin, pure gold should be adapted to the facing without bending 
the pins over upon it. (Fig. 167 A.) With the facing and backing in 
proper position in relation to the coping, the pins should be lubricated 
with oil or vaseline and hard casting wax then melted over and around 
them, and against the backing, and the desired form and contour made. DOWEL CROWNS 
193 
The facing then should be detached from the backing and coping care- 
fully. Small graphite points now should be inserted through the holes 
in the backing and to the full depth of the holes in the wax. (Fig. 167 B.) 
A slight surplus may be allowed to project beyond the backing. The sprue- 
former now should be attached securely (Fig. 167 C) and the crown in- 
Fig. 167. 
Fig. 168. 
vested and cast. After the casting has been made, boiling in dilute hydro- 
chloric acid will remove the graphite points. The crown then may be 
finished and the facing cemented to place subsequently. As a means of 
insuring a secure attachment of the cement, the pins may be notched with 
a file, or threaded with a tap made for the purpose. 
Soldering and Riveting. Where it is desirable to construct the 
crown through soldering the backing to the coping, instead of casting, the 
facings always should be backed with a reinforced backing in the man- 
ner described previously. A reinforced backing is the only means of in- 
suring a uniform thickness and adequate strength in the backing along 
its edges. 
When backed properly, without bending the pins, facing and backing 
should be placed in position on the coping and the relation sustained with 
adhesive wax. (Fig. 168 A.) The facing then should be detached and 
removed, and graphite points placed through the holes in the backing 
as indicated in Fig. 168 B. The crown now should be invested and sol- 
dered, the required contour being obtained at the same time. When the 
soldering has been completed, the graphite points may be removed with 
acid, the crown then roughly finished and the facing fitted to place. The 
ends of the pins may, or may not, project through the body of the crown. 
If they do not project through, the facing may be attached securely by 
cementation only. If they do project through, the attachment may be made 194 
CROWN AND BRIDGEWORK 
doubly secure by riveting their exposed ends down close to the surface 
of the crown. 
The process of riveting may be accomplished easily by investing the 
crown first in a large base of plaster, as indicated in Fig. 169. When this 
Fig. 169. 
Fig. 170. 
is crystallized thoroughly the riveting may be accomplished with a small 
riveting hammer. (Fig. 170.) If used carefully, any danger of fracturing 
the porcelain facing is overcome by the support and protection offered by 
the plaster investment. When the riveting has been completed the crown 
may be finished and polished. 
Temporary Dowel Crowns. 
In the construction of dowel crowns, the use of some simple form 
or type of temporary crown is indicated frequently. The application 
serves a double purpose. 
A temporary crown, mounted with gutta-percha or temporary stop- 
ping, either of which is satisfactory as a mounting medium, compresses 
the investing tissues and affords a free exposure of the root-end and DOWEL CROWNS 
195 
an immediate, though temporary, relief from disfigurement in emergencies. 
Both are desirable features. 
To obtain a good adaptation of the coping for a dowel crown without 
first compressing the investing tissues and obtaining a free exposure of the 
root-end is difficult in all cases and impossible in many others. 
Fig. 171. 
Fig. 172 
To dismiss a patient with a missing anterior tooth during the con- 
struction of a crown restoration is almost criminal negligence. Or, to be 
unable to afford relief from temporary disfigurement, in emergencies, is 
an acknowledgment of limited skilful resources. 
The simplest form of temporary crown, yet one which is most use- 
ful, may be made by using a flat-back facing, and attaching a dowel only. 
If one is provided with a limited selection of flat-back facings for the six 
anterior teeth, and with a few dowels made of 14 gage, round German 
silver wire, a temporary crown, which will answer the purpose nicely, 
may be constructed in a few moments. German silver wire in all sizes 
may be procured from dental and jewelers’ supply houses. (Fig. 171.) 
In this procedure, a facing which will approximate the requirements 
of esthetics should be selected. When the selection has been made, a dowel 
should be made and fitted to it. A length of 14 gage round wire adequate 
to the requirements of the case should be cut. The end which is to en- 
gage in the root canal should be tapered to fit the supporting root. It 
then should be annealed and the other end made flat and sufficiently broad 
to accommodate the position of the pins in the facing, when it has been 196 
CROWN AND BRIDGEWORK 
notched with a file for this purpose. This end may be formed, thus, with 
a hammer on a swaging block, or on a small laboratory anvil. (Fig. 172.) 
When it has been flattened and then notched to fit the pins closely, relation- 
ship between dowel and facing may be sustained securely by bending the 
pins over upon the wire, as illustrated in sequence in Fig. 173. 
If this mechanical attachment between facing and dowel does not ap- 
pear to insure adequate strength, facing and dowel may be invested, heated 
Fig. 173. 
carefully, and soldered. A low grade of gold solder, silver solder, or 
even soft solder, will answer the purpose. 
Any of the manufactured or ready-made porcelain crowns, either with 
dowels united or separable, also may be used to good advantage for tem- 
porary purposes. 
Ready-Made, All-Porcelain Dowel Crowns. 
Several types of ready-made, all-porcelain dowel crowns are manu- 
factured and may be used successfully. They are made with the dowel 
as an integral part of the crown, and with the dowel as a detached or 
separable part. A coping may or may not be used. 
When a coping is not used, the requirements of adaptation are obtained 
by grinding the basal end of the crown to fit both the basal end and the 
periphery of the root. No greater accuracy is possible than the limited 
accuracy which is to be obtained through grinding one surface to fit an- 
other surface. Hence, a maximum of protection to the supporting root, 
and a maximum of permanency in the restoration is not obtainable, usu- 
ally, nor is it to be expected through the use of ready-made, all-porcelain 
dowel crowns. 
The type of crown in which the dowel is baked into the body of the 
crown, and thus is an integral part of it, was among the early achieve- 
ments in porcelain dowel-crown construction. (Fig. 174.) 
The difficulty in obtaining accuracy in the adaptation of the crown 
to the root, by grinding, is increased by the presence of an inseparable 
dowel. And this feature, together with the difficulty of obtaining an 
alinement with the crowns of the adjacent natural teeth without unnec- DOWEL CROWNS 
197 
essarily and, in some instances, greatly weakening the supporting root, 
have caused the practical abandonment of this type of crown, and the 
general use of crowns having separable, or detached, dowels. 
Indications. The use of ready-made, all-porcelain crowns adapted 
to the supporting root by grinding, and used without any form of coping, 
does not usually insure a maximum of permanency in the restoration. 
Fig. 174. 
Fig. 175. 
Hence, this type of crown is indicated mainly in the restoration of roots 
where great permanency is not demanded or is not expected. 
Requirements. The health of the supporting root and of its in- 
vesting tissues and the permanency of the restoration will depend en- 
tirely upon the accuracy of adaptation obtaining between crown and root 
at the line of junction and around the entire circumference—and will in- 
crease accordingly. 
Therefore it is evident that a good, close joint between the basal end of 
the crown and the basal end of the root must be made in order that a 
minimum of cement in the joint may be exposed to the action of the se- 
cretions. And it is evident, also, that the continuity of the root must 
be preserved by a close adaptation of the crown to its periphery in order 
that no irritation of the investing tissues may be offered. 
Application. In the application of ready-made, all-porcelain dowel 
crowns, the selection of the crown will be facilitated by taking a simple 
impression of the root first, including several adjacent teeth, with base- 
plate wax, and obtaining a plaster cast. (Fig. 175.) 
Selection of Crown. With a more or less accurate plaster cast as a 
guide, a crown which meets all requirements should be selected. Color, 
type, size, contact and alinement, together with a basal end which ap- 
proximates in size and shape the basal end of the root, must be considered 
in making the selection. 
If it is not possible to obtain a selection which approximates the size 
and shape of the basal end of the root, a larger, but never smaller, size 198 
CROWN AND BRIDGEWORK 
should be selected. A crown of larger basal-end proportions may be 
ground to a joint closely approximating the periphery of the supporting 
root, but one which is too small never can be adapted to a satisfactory 
degree of accuracy. 
Adaptation to Root. When a suitable crown has been selected, it 
should be ground slowly and carefully until the desired and required 
adaptation is obtained. The use of lampblack, mixed into a paste with 
vaseline, and painted on the basal end of the root, will aid materially in 
effecting a good, close adaptation. 
Increased Accuracy. Increased accuracy in the adaptation of the 
crown to the periphery of the root may be secured by first taking a single 
unit impression of the root-end in impression compound, and making an 
amalgam cast. 
The amalgam cast should be formed in the shape of a conical root of 
sufficient proportions to insure its retention in a plaster cast which is to 
be made subsequently. 
When the amalgam cast has crystallized, it should be finished roughly 
and the labial or buccal surfaces indicated or designated by a definite mark- 
ing. 
An impression of the root, together with the crowns of the adjacent 
natural teeth then should be taken with base-plate wax. The amalgam 
cast of the root now should be placed in its proper position in the wax 
impression, and sustained securely with melted wax. A plaster cast then 
should be made. When the cast has been obtained, the amalgam repro- 
duction of the root-end should be exposed freely by trimming away the 
surrounding edge of plaster. 
The desired adjustment of the porcelain crown to the amalgam cast of 
the root-end, and the requirements of alinement with adjacent teeth, may 
be made then with greater accuracy than probably would be obtained from 
an effort to accomplish the adjustment directly in the mouth. This is 
possible because all surfaces of the amalgam cast of the root-end are fully 
visible, and because opportunity for correct alinement exists at the same 
time. 
Final adaptation and adjustment may be made directly upon the root. 
The dowel then should be adjusted to meet the requirements, and the 
crown mounted. 
Since the successful application of ready-made porcelain crowns de- 
pends entirely upon the degree of accuracy obtained in their adaptation 
to the supporting root, any effort which will insure greater accuracy will 
add materially to permanency. CHAPTER XIII. 
PORCELAIN CROWNS. 
Ceramics is the highest achievement in modern dental art. From 
the time of the introduction of “mineral” teeth, first suggested by Fauchard 
and later by Duchateau, to the present time, the possibilities of porcelain 
work have been recognized. 
As a means of simulating closely the natural teeth in color, form and 
texture, and as a means of attaining the highest requirements in the direc- 
tion of hygiene and sanitation, and, therefore, in the conservation and 
promotion of health, porcelain work stands preeminent. It stands alone. 
The primitive application of porcelain was made to the restoration of 
the crowns of teeth as single units. These restorations were known as 
“pivot” crowns. This was followed by the application of porcelain to 
denture construction. 
The discovery that various minerals might be combined arid made to 
form a compound which would be applicable and controllable, and which 
would possess and afford all the desired esthetic and hygienic advantages 
in the reproduction of the natural teeth, as single units, led to further 
experimentation with a view to producing a color which would simulate 
closely the color of the contiguous soft tissues. 
The color problem soon was mastered successfully and no vegetable 
compound yet discovered even approaches the close simulation to the color 
of the soft tissues which can be obtained with porcelain. 
The problem of color having been mastered successfully, further de- 
velopment resulted in the control of fusibility, and in obtaining success- 
fully and retaining permanently a given form or shape. The latter re- 
quirements were made possible by the use of platinum. This member of 
the small group of noble metals is adapted peculiarly to the requirements 
of porcelain work. It possesses the desired and required physical prop- 
erties of malleability and high fusibility. Its malleability permits accu- 
racy of adaptation, and retention of given form and shape. And its high 
fusibility, irrespective of thickness, permits it to withstand the varying de- 
grees of temperature required by high-fusing porcelain compounds. 
199 200 
CROWN AND BRIDGEWORK 
Originally, porcelain compounds were made in two grades only. One 
grade was known as “foundation body” and the other was designated as 
“enamel body.” The foundation body was the same as was used in making 
porcelain teeth, and the enamel bodies were pink in color and fused at 
a temperature lower than that required to fuse the foundation body. 
Full porcelain dentures made upon a base of platinum were suggested 
and perfected by and through the early efforts of Dr. John Allen and Dr. 
S. L. Close. This type of artificial denture became known as “continuous 
gum” work, and, in many respects, continuous gum dentures afford the 
highest and most ideal type of construction. 
The early efforts in fusing these compounds were confined to the use 
of a coke furnace and a bellows. This crude method of heat production 
required considerable effort and much time and usually was done at night. 
Idle successful application of porcelain, in combination with a base of 
platinum, to denture construction was followed by the advent of the por- 
celain jacket crown made upon a platinum matrix, as orginally suggested 
and perfected by Dr. C. H. Land. The matrix was and is used only for 
the purpose of insuring accuracy of adaptation and retention of form, and 
subsequently is stripped off or removed entirely. And, originally, when 
various colors were desired they were obtained by breaking and pulver- 
izing porcelain teeth of proper color. 
The advantages obtaining from the successful application of porce- 
lain to denture construction, and, later, to jacket crown restorations, were 
soon recognized as being of such importance as to demand better facilities 
for baking or fusing porcelain compounds, and as possessing such desirable 
features as to warrant a more general application to the field of crown and 
bridgework. 
The use of gas and gasoline furnaces followed, and while these methods 
of heat production were an improvement upon the former primitive 
method, the noise and odor incident to their use was objectionable. Fur- 
thermore, the integrity of the porcelain and the preservation of its color 
were endangered always by the possibilities of “gassing” or of gas con- 
tamination. 
The ingenuity of the profession, however, soon proved equal to the 
demands, and the advent of the electric furnace followed. This refined 
method of heat production was the missing link, and the electric furnace 
has eliminated all former objectionable features and dangers incident to 
fusing porcelain and now is used exclusively. 
Porcelain compounds were improved correspondingly and now are 
made in several grades, with different degrees of fusibility and in varying 
colors. PORCELAIN CROWNS 
201 
With these improvements in materials and in facilities, the scope 
of porcelain work became enlarged, and its application to the construction 
of dowel crowns, and to all forms of bridgework followed. 
As applied to the construction of dowel crowns with platinum coping 
and porcelain facing, the application of porcelain was and is more or less 
successful. 
The application of porcelain to bridgework, however, was more or 
less disastrous. Early efforts proved unsuccessful because porcelain is 
a friable substance, and even though supported and protected by a strong 
and well-built platinum superstructure, it is not applicable universally. 
Failure, however, was attributable to injudicious application, or to 
faulty technic, or both, perhaps more than to the inherent weakness of the 
porcelain itself. 
There is no legerdemain, no wizardry, about porcelain work. Its suc- 
cessful application is but a question of skill; nothing more, nothing less. 
It has passed through the experimental stages and now is recognized as 
a necessary and permanent part of modern dentistry; and as being an art 
encompassing a field of usefulness almost unlimited in scope. 
Jacket Crowns. 
The porcelain jacket crown is the most ideal type of crown restoration. 
It stands to-day and must stand always as the one ideal method of re- 
storing the crown of a natural tooth as a single unit. From all viewpoints 
it meets all requirements to an extent which completely overshadows all 
other methods and to such an extent that the author of this book feels 
it a duty to broadcast its advantages to the limit of his ability; and to 
indulge and express the wish that some day it might be possible to use no 
other type of crown in effecting the restoration of the natural teeth. 
If the all-porcelain jacket crown might be used universally, and to the 
exclusion of all other methods of crown restoration, dental art would be 
placed upon a higher plane; dental skill would be of an order immeasur- 
ably higher, and greater health of teeth and of investing and environmental 
tissues would obtain, and would be maintained. 
Advantages. The advantages obtainable from the use of all-porcelain 
jacket crowns may be enumerated, specifically, as follows: 
First: Esthetic. 
The possibilities for reproducing tooth-form and color with exactness, 
and for simulating type and characteristics with artistry and accuracy are 
limited only by the skill which may be acquired, developed and displayed 
along these directions. 202 
CROWN AND BRIDGEWORK 
Second: Hygiene and Sanitation. 
Porcelain being a vitreous substance, it presents a surface when fused, 
which is absolutely non-irritating and non-absorptive, and, hence, a surface 
which is kept clean easily. 
Third: Promotion and Maintenance of Health. 
It is recognized that the investing tissues take more kindly to porcelain 
than to gold or platinum. Hence, any degree of mechanical irritation is 
unnecessary and may be eliminated entirely in proportion as accuracy of 
adaptation may obtain. And in proportion as the possibilities of irritation 
may be eliminated, the health of these tissues will be promoted and main- 
tained. 
Fourth: Pulp Conservation. 
The application of porcelain jacket crowns permits pulp conservation 
and the advantages of pulp conservation are recognized as among the 
most important considerations incident to the restoration of the crowns of 
teeth. 
Fifth: Non-conductivity. 
Porcelain being a good non-conductor of thermal changes, the possi- 
bilities of shock to the nerve and blood supply of the pulp, with its possible 
devastating influence, is eliminated entirely. 
Sixth: Influence of Light. 
The influence of light is recognized as exercising a normal stimulation 
to the vitality of the tooth pulp. Porcelain is translucent; and, while 
jacket crowns are mounted with cement, which is not translucent, but which 
is opaque, translucency is not overcome entirely by the opaqueness of the 
cement used in mounting because of tbe thinness of the layer intervening 
between the porcelain and the pulp. Hence, the possible stimulating in- 
fluence of light, while diminished, is not overcome entirely. 
Seventh: Masticatory Efficiency. 
Masticatory efficiency is an important consideration in the restoration 
of the crowns of the posterior teeth, particularly, and a surface of porce- 
lain is recognized as affording greater efficiency than is afforded by a 
surface of gold. Gold, whether finished roughly or polished highly, will 
wear smooth, while porcelain is not so susceptible to the influence of con- 
tinued attrition. 
Eighth: Strength. 
Porcelain, by no means, is indestructible, nor is it as inherently strong 
as gold. And, yet, a degree of strength adequate to the requirements of 
stress may be obtained from the use of high-fusing compounds. Adequate 
strength will be secured provided first, that the supporting tooth is pre- PORCELAIN CROWNS 
203 
pared properly; second, that the porcelain is not overfused; and, third, 
that functional occlusion is insured. 
Indications. Cases may and do present where the requirements of 
occlusion demand absolute indestructibility in the restoration, and where 
proper preparation of the supporting tooth to receive and sustain a porce- 
lain jacket crown is inadvisable or impossible. 
In such cases some other method of restoration is indicated, may be 
preferable, or may be demanded. But, with these exceptions, porcelain 
jacket crowns are applicable more or less universally. 
They are applicable to the restoration of posterior teeth as well as to 
anterior teeth, and they are applicable to pulpless teeth, as well as to 
teeth having vital pulps. Their use is indicated, therefore, in the restora- 
tions of the crowns of all teeth when the restoration is to be made as a 
single unit, and when skill equal to the requirements has been developed. 
Requirements. In the building of porcelain jacket crowns, several 
basic requirements are essential to successful achievement. These are as 
follows: 
First: Detail. 
It must be recognized that exactness in technic is demanded. The de- 
velopment of skill in porcelain work is simply a question of ambition and 
of application, combined with a recognition and appreciation of the fact 
that exactness in technic must be observed, in sequence, from the beginning 
to the end of the procedure. 
Second: Preparation of Supporting Tooth. 
It must be observed that the supporting tooth is prepared properly. 
Where the root preparation involves the making of a shoulder the require- 
ments, as indicated previously, demand that the shoulder be formed defi- 
nitely and properly; that it be placed well within the gingival border, be 
smooth and continuous, and that no undercuts present. If undercuts do 
present, they must be filled with cement and polished until smooth surfaces 
obtain. 
Third: Stress. 
A study of the adjacent natural teeth, of the opposing teeth, and of 
the demands of occlusion, constitute a basic requirement. This is essential 
in order that the requirements of stress may be adequately met from tbe 
viewpoint of each individual case. 
Fourth: Type. 
A study of the type and characteristics of the adjacent and opposing 
teeth must be made in each case. This is necessary in order that the res- 204 
CROWN AND BRIDGEWORK 
toration may simulate closely the natural teeth in all of their characteris- 
tic features. 
Fifth: Color. 
The Color Problem 
A fundamental knowledge of the phenomena of color is essential to 
the achievement of the highest possibilities in esthetics. This scientific and 
exacting problem is an interesting study, and a knowledge of the physical 
manifestations of color, of the interpretation of colors, and of the psychol- 
ogy of color vision will be helpful in the application of porcelain work 
to any of its fields of usefulness. 
In the development of skill and in the accomplishment of successful 
results, it is necessary to know, fundamentally at least, that sunlight is the 
greatest source of illumination; that it is a white light; that it is the most 
perfect light, and that it is the source of all color; and, therefore, the 
standard by which color is judged. 
It is necessary, also, to know that sunlight is composed of the color 
rays of all colors, and that the physical manifestations of color is pro- 
duced by the reflection of certain rays of light not absorbed by the object, 
and that these reflected rays are perceived as a distinct color. 
It is necessary to know, furthermore, that the interpretation of color 
depends upon at least three varying conditions: 
First, intensity; second, phenomena in the body itself; and, third, the 
individual peculiarities of the eye which views. 
Thus, briefly, in proportion as sunlight is diminished in intensity, color 
appears darker and is interpreted differently; also, when viewed under 
the rays of any illuminant other than sunlight, the rays being different, 
the reflection is different, and, hence, the color is different. 
It is observed, also, that the phenomena in the body itself control its 
color, and that the same object, whether transparent, translucent, or 
opaque, may be made to appear different by diminishing its thickness, or 
by altering its surface condition. And that a rough, or an uneven, or ir- 
regular surface always appears darker than a surface which is smooth and 
highly polished. 
It is found, too, that the difference in refraction in individuals, and 
the variations at different ages, are important considerations, and that 
it is estimated that at least five per cent, of the human race is “color 
blind.” 
All of these considerations have an important bearing upon the inter- 
pretation of color, and cause the problem of color to be a difficult one. 
Hence the matching, the production and the reproduction of color or of PORCELAIN CROWNS 
205 
colors is a question largely of individuality. Therefore no standard rules 
which will be applicable universally may be formulated. 
However, certain definite rules for obtaining, or matching, color are 
applicable to all, and should be observed carefully. These are as follows: 
First: Good light is essential to accurate color selection. 
Second: The patient should be placed in the proper position in relation 
to the source of light. 
Third: The teeth to be matched must be clean and free from stains. 
Fig. 177. 
Fig. 176. 
Fig. 178. 
Fourth: Any and all discoloration caused by caries should be removed. 
Fifth: The teeth to be matched should not be dry. 
Sixth: There are two colors in almost every tooth; both should be 
matched. 
Seventh: One must know and be a master of the colors with which he 
works. 
Technics of Construction. 
Many methods of procedure are followed in the technic of building 
porcelain jacket crowns. Almost every skilful craftsman develops and 
adopts a technic which is suited best to himself, and from and by which 
he can obtain the best and most certain results, without waste of time. 
It is results, in the composite, which count in the end, and the method 
of procedure followed in obtaining the result is of interest and importance 
to others, only in proportion as it may be applied and utilized by others. 
Hence, a technic which may be followed successfully by the greatest num- 
ber, and which will insure uniformly successful results in the largest pro- 
portion of cases should be followed. 
No effort to save time at the expense of results, or at the expense of 
accuracy and certainty, ever should be made. 206 
CROWN AND BRIDGEWORK 
Impressions and Casts. Porcelain jacket crowns must be built by 
the indirect method. Hence, good, reliable impressions and good accurate 
casts are the first essentials to success. 
Unit Impression. A unit impression of the tooth, or root, must be 
obtained first. When the preparation has been completed satisfactorily 
Fig. 179. 
Fig. 180. 
Fig. 181. 
as illustrated typically in Fig. 176, an impression band (Fig. 177) made of 
copper or aluminum, should be selected and fitted. It should be fitted 
so that it will pass freely over the shoulder and should be trimmed to 
follow the gingival curvature closely; and this should be done before the 
shoulder is formed. (Fig. 178.) A mark to designate the labial or buccal 
surface then should he made. (Fig. 179.) The band should be filled with 
hard, stick impression compound, softened over a flame. The impression 
then should be taken by forcing band and softened compound over the 
tooth firmly. (Fig. 180.) When well seated, with a slight surplus of com- 
pound showing around all surfaces (Fig. 181), it should be chilled with a PORCELAIN CROWNS 
207 
spray of cold water, and then removed. If a good imprint of the shoulder 
around the entire circumference presents (Fig. 182), the impression is 
satisfactory. If a good imprint does not present, the compound must be re- 
heated and the procedure repeated until a good impression is obtained. 
When a satisfactory unit impression has been obtained, a small piece of 
impression compound, or of temporary stopping, should be softened in the 
flame and molded over the tooth to form a coping. This coping should 
Fig. 182. 
Fig. 183. 
cover all of the exposed tooth surfaces, but should not come in contact 
with the crowns of the adjacent teeth. (Fig. 183.) 
Impression of Adjacent Teeth. An impression, including several 
adjacent teeth on either side, now should be taken with the coping made 
of compound or temporary stopping, in position on the tooth. Plaster or 
baseplate wax may be used for the impression. Plaster is much more 
accurate and reliable and, therefore, is preferable. When the impression 
is removed, the coping will come away with it. 
Taking the Bite. The bite now should be taken in base-plate wax. 
This procedure may be effected in the best manner by lubricating the in- 
terior surfaces of an adjustable partial impression tray with oil, glycerin, 
or vaseline, filling the tray with base-plate wax of proper plasticity, and 
then forcing it to place over the opposing teeth. A good imprint, which 
is desirable, thus is obtained of the opposing teeth. The tray should be 
removed from the wax immediately, and, while the wax is still soft, the 
patient should be instructed to close firmly. Then, by pressing the wax 
with the fingers firmly against the labial or buccal surfaces of the adjacent 
teeth, and instructing the patient to do likewise upon the lingual surfaces 
with the tongue, and observing that the teeth are held firmly in centric 
occlusion a good, accurate bite results. 
While the use of an impression tray in taking the bite is not absolutely 
necessary, still, a good, deep imprint of the crowns of the opposing teeth 208 
CROWN AND BRIDGEWORK 
insures a good reproduction of these teeth in the cast, and a good repro- 
duction of the opposing teeth, however it may be obtained and insured, is 
desirable always. 
The selection of color and the temporary protection of the prepared 
tooth now should follow. 
Fig. 184 A. 
Fig. 184 B. 
Temporary Protection. The temporary protection of the tooth, 01 
root, and the compression of the gingival tissues during the period re- 
quired to build the crown, is important. 
In posterior teeth this may be accomplished satisfactorily by packing 
temporary stopping over the exposed tooth tightly, and molding it to fill 
the space and to preserve the alinement between the adjacent natural 
teeth. This same procedure is applicable also to the anterior teeth, but 
an equally useful and a more esthetic result may be secured easily and 
quickly by making a temporary restoration with the silicate cements. 
Silicate Cement Crowns. Thin, transparent tooth-crown forms, 
made of celluloid, are useful for this purpose. In the use of these forms, 
one which will meet the requirements of the case should be selected, 
trimmed and fitted. (Fig. 184, A.) Silicate cement of the proper color 
now should be mixed in the proper consistency and packed tight into PORCELAIN CROWNS 
209 
the celluloid form. The exposed surfaces of the tooth then should be 
lubricated slightly to facilitate the subsequent removal, and the form 
filled with silicate and then forced to place over the tooth. When the 
silicate has become thoroughly crystallized, the celluloid form may be 
removed by cutting it with a thin, sharp blade. The requirements of 
Fig. 185, 
occlusion now should be noted carefully, and any necessary change in 
form or contour made. (Fig. 184, B.) Such crowns may be worn 
more or less indefinitely, and, because of having used a lubricant pre- 
vious to mounting, they are removed easily at any time. 
Crown restorations made of the silicate cements and formed in this 
manner are recommended for permanent restorations by the manufac- 
turers of these products, but some doubt as to the permanency of form 
and color prevails. 
Where restorations are made in this manner with a view to obtaining 
whatever degree of permanency the procedure may afford, the supporting 
tooth should not be lubricated, but should be dried thoroughly and then 
covered with a thin layer of ordinary crown and bridge cement previous 
to mounting. For the reason that silicate cements are not adhesive, the 
use of cement is advantageous. 
Obtaining the Casts. When the unit impression, the impression of 
the adjacent teeth and the bite have been obtained, and when the tooth 
has been protected, as indicated, the work then is transferred to the 
laboratory. 
Amalgam Cast. An amalgam cast of the tooth should be made first. 
To make this the unit impression should be surrounded with a rim of 
thin, sheet wax in such manner as to form a matrix for building and 210 
CROWN AND BRIDGEWORK 
forming the amalgam cast. The wax rim should be of a width which 
will afford a root-end extension to the cast. (Fig. 185 A.) This now 
should be invested in plaster even with the edge of the wax rim. When 
the plaster has crystallized, the impression should be filled with amalgam, 
packed carefully and firmly. 
Quick-setting amalgam alloys are prepared for this and other labora- 
tory purposes. Cement is used also for making the unit cast, but cement 
is not indestructible, and, hence, is not accurate nor reliable. 
Fig. 186. 
When the amalgam has crystallized thoroughly, the plaster invest- 
ment should be broken away, using a sharp blade and a hammer. Im- 
pression and cast should be placed in hot water and separated. The 
root extension then should be trimmed down with disks until a typical 
root of conical formation, with a mark to designate the center of the 
labial or buccal surface is secured. (Fig. 185 B.) No undercuts along 
any of the surfaces should present and finishing to the point of polishing 
is advantageous. 
Plaster Casts. When the amalgam cast has been finished, and when 
the plaster impression has been varnished, the cast should be placed in cor- 
rect position in the impression. The coping of compound or temporary 
stopping, which is a part of the impression, will permit of its accurate 
placement, since it was made and is used for this purpose exclusively. 
(Fig. 186.) The relationship should be sustained securely with melted 
wax, and the cast poured with plaster. When separated, the compound 
or temporary stopping coping should be heated slowly and removed care- PORCELAIN CROWNS 
211 
fully. The bite now should be adjusted carefully and the case mounted 
upon the articulator. 
Indestructible Surfaces. Indestructible surfaces in the reproduction 
of the crowns of the adjacent teeth, as a part of the plaster cast, may be 
Fig. 187. 
Fig. 188. 
obtained easily, and add materially to the accuracy of the cast, and thus 
to the accuracy of the work being built upon it. 
This advantage applies particularly to the mesial and distal surfaces 
and contact points of the teeth immediately adjacent to the restoration. 
It is obtained by filling the imprint of these teeth in the impression with 
amalgam, and permitting the amalgam to crystallize before pouring the 
cast. 
When this procedure is to be followed, quick-setting amalgam alloy 
should be packed carefully and firmly into the imprints of the crowns 
of the adjacent teeth, after the impression has been varnished. While 
the amalgam is still plastic, the head of an ordinary pin should be im- 
bedded into the amalgam in the center of each tooth. The pin will 
become attached to the amalgam and will sustain it securely in its rela- 
tionship to the cast. (Fig. 187.) 212 
CROWN AND BRIDGEWORK 
After the amalgam has crystallized, the cast should be poured with 
plaster. When separated, the cast presents an accurate and indestructible 
reproduction of the crowns of the adjacent teeth. (Fig. 188.) Casts 
made in this manner insure accuracy at all times, and should be used 
invariably. 
When the casts have been mounted upon the articulator, and the wax 
bite removed, the amalgam cast of the root should be detached from 
the plaster cast in such manner as to permit of its replacement with 
accuracy. Casts thus obtained present all the advantages of indestructi- 
bility and of increased accuracy. 
In building bicuspid and molar restorations, the reproduction of the 
occlusal surfaces of the opposing teeth may be made in the same manner, 
and such procedure will afford the same advantages. 
Fig. 189. 
Restoring Pulpless Teeth. 
Porcelain jacket crowns, with a shoulder, also are applicable to the 
restoration of the roots of teeth the crowns of which have been sacrificed 
previously, or which must be sacrificed to the gingival line, and restora- 
tions so made present all of the advantageous features which have been 
mentioned. Indeed, such restorations are made even more easily because 
the requirements of root preparation are not so exacting, and the forma- 
tion of a shoulder is simplified. 
In the restoration of the roots of teeth where the natural crowns 
have been, or must be sacrificed to the gingival line, however, a restoration 
approximating the normal outlines of the dentin should be made previous 
to, and independent of, the porcelain crown restoration itself. 
Making Cones. Such restorations are called “cones” and may be 
made by the casting process, either of gold or silver. The use of gold 
alloy similar to that used for casting crowns and inlays, however, is recom- 
mended, and such restoration can be made best by the indirect method. PORCELAIN CROWNS 
213 
Indirect Method. In making a cone it is necessary to observe, first, 
that the margins of the basal end of the root are carried to a point within 
the gingival border. 
The canal should be prepared and a dowel made of iridio-platinum or 
high-fusing clasp-metal alloy and then fitted. The dowel should extend 
into the canal to a depth adequate to the requirements of strength, with 
a surplus end projecting incisally or occlusally to a considerable extent, 
but always free from contact with the opposing teeth. (Fig. 189.) 
An impression band now should be fitted to the root and trimmed 
and marked as indicated. It should be observed also that the band does 
not interfere with the opposing teeth. The unit impression of the root, 
with the dowel in place, then should he taken in the manner indicated. 
When a satisfactory unit impression has been obtained, the bite should 
be taken in base-plate wax with the unit impression in place. Following 
the bite, the impression of the adjacent teeth should be taken in plaster, 
or base-plate wax, also with the unit impression in place. Both will be 
removed together. 
The unit impression, with the dowel in place, now should be detached 
and removed from the plaster impression and the amalgam cast of the 
root made separately. To prevent the dowel from becoming attached 
to the amalgam cast which is built over and around it, the dowel should 
be painted with melted wax before packing the amalgam. This precaution 
will prevent attachment by amalgamation, or disintegration by mercury, 
and permit of the removal of the dowel from the amalgam cast subse- 
quently. In forming the amalgam cast, the root extension should be 
made conical in shape, and undercuts should be avoided. 
When the amalgam has crystallized it should not be separated from 
the impression, but, still attached, both should be placed in accurate posi- 
tion in the plaster impression and the cast poured with plaster. After 
separating the plaster cast from the impression, the bite should be adjusted 
and the case mounted upon the articulator. 
The taking of a bite and the making of occluding casts is necessary 
always in building restorations for the posterior teeth, but not always 
necessary in anterior teeth. 
When the casts have been obtained, the impression band and impression 
compound should be warmed and removed carefully. The dowel now 
should be warmed, detached, and cleaned in the acid bath; then replaced. 
A cone of desired shape and form, and which will leave a suffi- 
cient width of tooth surface exposed to form a shoulder around the entire 
circumference should be made over and around the exposed end of the 
dowel, with casting wax. The cone must be made of a shape favorable 214 
CROWN AND BRIDGEWORK 
to the requirements of the porcelain jacket crown which is to be made 
over it ; and accommodation for an adequate thickness of porcelain must 
be provided. 
When so formed, the sprue-former should be attached securely, and 
the investment and casting made. When the casting has been made, it 
Fig. 190. 
Fig. 191 
should be finished and polished, then placed in position on the cast, and 
the porcelain crown built. 
While greater accuracy may be obtained by making the cone by the 
indirect method, the direct method may be used successfully in restoring 
the anterior teeth particularly. 
Direct Method. Where the direct method is to be followed, the 
restoration, or cone, should be made first with casting wax directly upon 
the root and with the dowel in position. When trimmed and formed to 
the desired outlines, the casting should be made, finished and polished. 
It is then placed in position on the root, the impressions and bite taken, 
the casts obtained and the porcelain crown made. The same procedure 
which is followed where the natural tooth crown remains is observed. 
When the porcelain crown is completed, cone and crown are mounted at PORCELAIN CROWNS 
215 
the same time. The steps in order and in detail for anterior teeth are 
illustrated in Fig. 190, and for posterior teeth in Fig. 191. 
Making the Matrix. Platinum foil, 1-1000, is used for the matrix. 
The formation or adaptation of the matrix to the amalgam cast may be 
obtained by burnishing or by swaging. 
Fig. 192. 
If the adaptation is to be made by swaging, the amalgam cast should 
be imbedded in a ring filled with impression compound, leaving only the 
crown and shoulder exposed freely. Any of the crown swaging presses, 
or cylinders, which include a plunger of soft rubber may be used. 
Burnishing, however, is productive of results which are equally 
accurate, and the procedure is simpler. 
In obtaining the formation of the matrix for the anterior teeth by 
burnishing, a piece of platinum foil of proper proportions should be cut 
of rhomboidal shape (in the form of a diamond) with the greatest 
diameter mesiodistally. (Fig. 192 A.) 
Holding the amalgam cast in the fingers, place one of the shorter 
points at the center of the labial, or buccal, surface of the cast, well up 
on the root, and freely beyond the shoulder. Then fold the opposite point 
over the lingual surface of the cast, and burnish with the fingers until the 
outline of the shoulder around the entire circumference obtains. Then 
hold the finger firmly against the foil and cast upon the labial or buccal 
surface; sustain their relation and open the matrix. 
Then cut off the excess as indicated in Fig. 192 B, and cut a slit at 
the mesial and distal angles of the labial surface to a point approximating 
the incisal angle. Now fold this central flap over the incisal end (Fig. 
192 C) to the lingual surface of the cast, and then again close the lateral 
wings of the matrix around the shoulder. 216 
CROWN AND BRIDGEWORK 
Bring the ends of these wings together with foil pliers, and cut off 
the excess, leaving enough excess, however, to make a double lap. Now 
remove from the cast and cut away all unnecessary gingival excess, allow- 
ing a surplus of about two millimeters to project beyond the shoulder 
Fig. 193. 
Fig. 194. 
Then replace the matrix upon the cast and complete the burnishing, using 
wood points and blunt-end instruments. 
Complete the burnishing upon the labial surface first, and burnish 
always toward the joint. When well adapted, the surplus ends at the 
joint should be pulled together tight, and then lapped over again in the 
same direction in which the flaps were folded originally. (Fig. 193 A.) 
This double lapping of the surplus at the joint is necessary as a means 
of sustaining the form and shape of the completed matrix. Any unneces- 
sary surplus presenting upon the lingual surface, and due to the concave 
outlines of this surface, may be cut away before the final burnishing, and 
the thickness of the joint at the shoulder (Fig. 193 B) may be diminished 
with a small, fine-grit stone. 
The completed matrix, showing the extent of surplus which should 
be permitted to overlap the shoulder, and which is necessary as a means 
of guarding against any change of form which might be caused by shrink- 
age in the fusing of the porcelain is illustrated in Fig. 193 C. PORCELAIN CROWNS 
217 
In adapting the matrix to bicuspids and molars, the same procedure 
is followed except that a strip of platinum foil of proper size, and having 
straight edges, is used to begin with, and that a slit is cut at every one 
of the four occlusal angles. (Fig. 194.) 
Any unnecessary surplus should be cut away from time to time as the 
burnishing progresses, and the adaptation may be facilitated by annealing 
occasionally. Annealing is accomplished best in the electric furnace. 
When the adaptation of the matrix has been completed, the porcelain 
then should be applied. 
Fig. 195. 
Jacket Crown Restorations Without Shoulder. 
Jacket crown restorations may be made successfully without a shoul- 
der by following the technic suggested by Dr. A. L. LeGro. In this 
procedure the supporting tooth is prepared in accordance with all the 
requirements indicated previously, except that no shoulder is formed. 
The unit impression band is trimmed carefully and fitted to pass freely 
within the gingival border. When fitted, the outline of the gingival 
border is then marked carefully around the circumference of the impres- 
sion band. (Fig. 195 A.) The impression in hard compound is then 
taken. When this is satisfactory a shoulder is built around the impression 
band with wax, about one millimeter in thickness, and following the 
gingival outline as marked. (Fig. 195 B.) The amalgam root cast is then 
made. When the cast has been separated a shoulder, following the 
gingival curvature, presents. (Fig. 195 C.) 
A study of this illustration in comparison with Fig. 185 B discloses the 
fact that in the former the shoulder in the amalgam cast is entirely within 218 
CROWN AND BRIDGEWORK 
the periphery of the tooth, whereas in the latter (Fig. 195 C), the shoulder 
is entirely external to the periphery, the dotted lines indicating the shape 
of the natural root. 
In the subsequent procedure the jacket crown is constructed upon the 
amalgam cast exactly as though it represented a shoulder crown prep- 
aration. Thus the finished crown will present with its external circum- 
ferential surface flush with the periphery of the amalgam cast, whereas 
the true periphery of the natural root is represented by the inner circum- 
ferential margin of the jacket crown. If placed on the natural root, the 
shoulder would impinge upon the gum tissues. This gingival shoulder 
therefore must be reduced to a thin edge and should be rounded in imita- 
tion of the natural enamel. To accomplish this without fracturing the 
porcelain, the jacket crown is placed on the amalgam cast, and the porce- 
lain and amalgam ground away coincidently, using fine stones kept wet. 
This ground surface of the porcelain is polished highly with fine disks 
lubricated with vaseline. The rounded margin thus produced fits under 
and supports the gingival gum tissues. 
This method of procedure makes the preparation of a shoulder on 
the supporting tooth unnecessary; insures the same accuracy of adapta- 
tion ; and affords a rounded edge at the line of junction between crown 
and root which more nearly simulates the normal condition. 
This type of jacket crown is especially applicable in the restoration 
of teeth in the mouths of young patients, where the pulps are large, 
and the cutting of a shoulder might cause an exposure, or too close 
an approach to the pulp. But whether in the young or the old a 
particularly close joint between the crown and the root is essential, in 
order to minimize the danger of irritation to and consequent recession 
of the gingiva. The surface of the root therefore should be planed 
and polished smooth, just as scrupulously as is done by the periodontist 
in treatment of diseased conditions. In this instance it is for prevention 
rather than cure. 
Porcelain Compounds, 
In the manipulation of porcelain compounds, one should be not only 
a master of the colors, but also of the compounds with which he works. 
And, to be a master of the compounds, he must know their composition, 
their physical properties and characteristics, and be familiar with the 
most advanced methods of manipulation. 
Composition. Porcelain compounds are supplied in powder form 
and are known as “bodies,” “enamels” and “gum enamels.” They are PORCELAIN CROWNS 
219 
composed of silica, feldspar, kaolin and a suitable flux, and are colored 
or tinted with metallic exodies. 
Silica. Silica is the dioxid of silicon, a very refractory and prac- 
tically infusible substance found in the form of agate and flint. It is 
the base of all true porcelain “bodies” and imparts structural strength to 
them. 
Feldspar. Feldspar is a double silicate of aluminum and potassium. 
This material is somewhat less refractory than silica, and is incorporated 
for the purpose of imparting stability to and increasing the translucency 
of the compound. 
Kaolin. Kaolin is the hydrated silicate of aluminum. This is a very 
fine grade of clay, and is a most essential ingredient, being incorporated 
as a binder, and for the purpose of imparting stability of form by hold- 
ing the particles together, and thus facilitating the molding and carving 
of the mass into the lesired shape. 
Flux. The flux is composed usually of carbonates of the alkaline 
metals, sodium and potassium, though in some classes of compounds 
the oxid of lead is used. 
The quantity and nature of the flux, and the manner of its incorpora- 
tion, determines the fusibility of the former refractory ingredients, and 
the tensile strength, or resistance to fracture, of the mass when all are 
fused together. 
Coloring Material. The coloring material used for the purpose of 
imparting the required variations of shade must be more or less high 
fusing in character, in order that the color or tint may not be dissipated 
or burned out in the fusion of the compound. 
While the coloring material itself practically has no influence upon 
the fusibility of the compound, the color imparted is affected materially 
by the degree of heat required. For this reason, metals, or metallic oxids, 
are used for this purpose, in which the basal shades imparted approxi- 
mately are as follows: 
Yellow Titanium 
Brown Iron 
Blue Cobalt 
Gray Platinum 
Pink (gum enamel) Silver and tin in combination 
with gold (purple of cassius). 220 
CROWN AND BRIDGEWORK 
The colors and tints characteristic of the different porcelain com- 
pounds are produced by the use of these various coloring materials in 
varying proportions, but the exact formulae and methods of procedure 
are of special interest to manufacturers only, and usually are carefully 
guarded by them. 
High and Low Fusing Compounds. 
Porcelain compounds may be classified into two distinct grades, high 
and low fusing, with the line of common distinction between them based 
approximately upon the fusing point of pure gold. 
Comparative Advantages. An analysis of the comparative advan- 
tages of the two classes of body demands some limited familiarity with 
the composition of these compounds, and with the characteristics of their 
respective ingredients. 
Silica, being the most refractory and infusible substance, it might be 
supposed that a body capable of being fused at a lower temperature than 
another necessarily would contain less of this ingredient and more feld- 
spar and kaolin in proportion. 
Such an assumption would be correct if the flux played a less con- 
spicuous part in the reduction, but the same relative formula of the three 
basal ingredients may be used, and yet the fusing point of the resulting 
compound be regulated by the proportions of the flux subsequently added 
to this formula. 
But as a body must possess sufficient inherent integrity and stability 
to ofifer a high degree of resistance to stress, and must possess translucency, 
an adequate proportion of these three basal ingredients seems essentially 
necessary since each has its place and purpose in the compound. 
This being apparent, if the fusing point is regulated or controlled 
by the proportion of flux, and if it is conceded that the latter does not 
impart to the compound the highest degree of strength, it is evident that, 
when a sufficient proportion of flux to reduce the fusing point of these 
refractory materials below a certain point is incorporated, the maximum 
degree of strength is not imparted to, nor obtained in, the product. 
It, therefore, seems evident that when a maximum degree of strength 
is to be obtained, such as is required in the construction of crown and 
bridgework, where the finished product is to assume the full stress of 
mastication, the compound which will serve the purpose best must possess 
the integrity and stability imparted by the three basal ingredients to a 
degree not destroyed entirely by the incorporation of too great a propor- 
tion of flux. PORCELAIN CROWNS 
221 
Shrinkage. All porcelain compounds shrink in fusing, in propor- 
tion to the degree of their fineness of texture, and the quantity and nature 
of the flux used; and the degree of shrinkage adds to the difficulties 
incident to their manipulation. It is estimated that the high-fusing com- 
pounds shrink one-sixth of their bulk, while the low-fusing compounds 
shrink up to twenty-five per cent. 
All of the compounds are translucent in proportion to the degree of 
fineness to which they are pulverized before fusing. The lower fusing 
bodies are reduced to a much finer texture in their preparation and hence 
they possess a greater density of structure. 
This increased density, however, is due to the more homogeneous 
coalescence of the particles, as a result of the more thorough admixture 
of the flux, and is gained at the expense of translucency and stability, 
since the flux, beyond a certain proportion, does not add integrity to the 
mass, but, on the contrary, increases the shrinkage, friability and tendency 
to globulate in fusing. 
A summary of the objections to the use of low fusing bodies thus 
consists in the degree of shrinkage; the diminished strength and trans- 
lucency, and the lack of stability of form and color possessed by them. 
These features cause their manipulation with accuracy and certainty 
to be more difficult, because of the necessity for discontinuing the heat 
the moment the fusing point is reached. This is imperative in order to 
avoid a dissipation of the color, and a loss of the desired form, as a 
result of their tendency to globulate immediately, beyond the point of 
fusion. 
For these reasons, the use of the low fusing, or so called enamel bodies, 
or those which contain a large enough proportion of flux to reduce their 
fusing point below that of pure gold, cannot be considered reliable for 
this work. 
Gum Enamel Bodies. The compounds designated as gum enamel 
bodies contain a larger proportion of flux than basal bodies, and, 
consequently, fuse at a lower degree of heat, and possess less strength. 
Hence, when their use is indicated for the purpose of producing an 
artificial restoration of gum color, the major portion of the contour of 
the piece should be made of basal body, and the gum enamel applied 
subsequently where necessary, and only for the purpose of imparting 
the color. 
Previous to the application of the gum enamel, the basal body to be 
covered by it should be fused until it presents a fairly smooth and well 
vitrified surface. This is necessary because it is not to be refused, and 222 
CROWN AND BRIDGEWORK 
the maximum degree of strength will not obtain until its particles are 
well coalesced, and all shrinkage has taken placei 
Requirements for Crown and Bridgework. 
A compound possessing qualities adaptable to the maximum require- 
ments for crown and bridge-work must belong to the high-fusing variety, 
and should be prepared in one grade of a sufficient variety of colors, and 
pulverized only to a degree of fineness which will admit of being carved 
nicely. This latter feature is essential, because the shrinkage is increased 
and the fusing point decreased, in any given compound, in proportion 
to the degree of fineness in which it is prepared. 
The following porcelain compounds are made especially for, and are 
supplied in a variety of colors quite adequate to the requirements of this 
work: 
S. S. White high-fusing 2560 degrees F. 
Justi 2500 degrees F. 
S. S. White crown and bridge 2300 degrees F. 
In building jacket crowns, one grade of body should be used through- 
out, and greater strength and better color are obtained from the use of 
the higher fusing bodies. A lower fusing body is useful mainly for 
making any final touches such as increasing contact points, producing 
sharp angles and in making any addition to or changes of contour or 
color which may become necessary. 
Use and Manipulation of Porcelain Compounds. 
Selection of Color. The colors selected should match the shade of 
the natural teeth as closely as possible. The shade-guide, which accom- 
panies the porcelain compounds, is not always reliable. Hence, it is 
safer to make a shade button from the contents of each jar of compound 
before using it. 
If the exact color cannot be matched, and some variation becomes 
necessary, a shade slightly darker should be used, in preference to one 
which is lighter, owing to the possibility of bleaching in fusing. In this 
connection it should be remembered that the true color of porcelain com- 
pounds will be exhibited only when they are fused to the exact point of 
complete vitrification, and that they will become lighter in shade as they 
are carried beyond, or above, this point. PORCELAIN CROWNS 
223 
Mixing Body. An adequate quantity of the body selected should 
be placed upon a clean glass, porcelain, or agate mixing slab, and, using 
distilled water or alcohol, mixed thoroughly with a suitable spatula, until 
it assumes a thick, plastic consistency. As it is mixed, the water or 
alcohol may be added in the most convenient manner by means of a 
“dropper.” 
Sufficient water or alcohol to insure the desired consistency and thor- 
ough mixing are quite essential. Any surplus of body is not wasted, 
because what remains unused may be placed in its proper container and 
used at another time. 
Alcohol is used because of its rapid evaporation, but this is more 
often an objection than an advantage. Clean, pure water is preferable. 
It should be distilled, however, because the presence of the lime salts, 
or organic matter, is objectionable. 
The addition of a small quantity of gum tragacanth is recommended 
as furnishing a means of increasing the cohesion of the mix and thus 
facilitating the carving and contouring. Its use is objectionable, how- 
ever, because it acts as a flux. The manufacturers of porcelain compounds 
usually incorporate a small proportion of gum tragacanth, or of starch, 
for this special purpose. 
Applying and Building. In the manipulation of porcelain com- 
pounds, it must be remembered that shrinkage plays quite an important 
part, and must be taken into consideration at all times. 
One Grade of Body. In the use of one grade of body throughout 
the construction of the case, the desired shape and contour for the finished 
crown should obtain for the first, or primary, bake. It is seldom pos- 
sible, however, and rarely ever expedient to complete the case in one 
bake because of the shrinkage. 
This feature of shrinkage necessitates two, and sometimes even three 
bakes, but by forming the desired contour, even to the requirements of 
occlusion and approximal contact for the primary bake, the second 
application of body is made for the purpose of restoring the original form 
to the extent to which it has been changed by shrinkage. 
The matrix must be perfectly clean before applying the body. This 
is to be insured by passing it over a flame until a red heat obtains. It 
then should be placed in position on the amalgam cast, and a small piece 
of heavy paper previously cut to the required size, wrapped around the 
cast and matrix in such manner as to form a wall (or matrix) for the 
purpose of sustaining the porcelain in contact with the platinum matrix, 
of aiding in building the porcelain to the required proportions, and of 224 
CROWN AND BRIDGEWORK 
facilitating packing it firmly. Any kind of paper, except one haying a 
glazed surface, may be used. When the paper matrix has been adjusted 
it may be held in place by tying it with a ligature. 
A small quantity of body, mixed to the proper consistency, should be 
picked up with the point of a suitable instrument and first placed against 
and packed around the shoulder. This may be facilitated by gently tap- 
ping the amalgam cast, or by drawing a coarsely serrated instrument 
across it, and this procedure should be continued until the paper matrix 
is completely filled and the body is packed thoroughly. 
A convenient carving instrument designed for universal use in this 
work is illustrated in Fig. 196. 
As a means of insuring a high degree of strength in the compound 
when fused, and of overcoming porosity in fusing, by insuring a close 
and compact coalescence of the particles, the feature of condensation is 
imperative throughout the entire building up of the crown. 
Fig. 196. 
As the building up progresses, and as each additional application of 
body is carried to place, and the contour formed, the procedure may be 
facilitated by absorbing the excess moisture as it is brought to the sur- 
face. A clean piece of linen, or cotton cloth, or blotting or bibulous paper 
may be used for this purpose. 
The latter part of the procedure may be facilitated by mixing the body 
to a thicker consistency. 
When the required form has been obtained, any remaining excess 
moisture should be evaporated by passing it over a flame, or by waiting 
until the mass is sufficiently dry to retain its form and to admit of being 
carved nicely. It should be allowed to remain moist enough, however, 
to be carved and trimmed without flaking or crumbling, and in the event 
of its becoming too dry to admit of fine carving, it may be moistened 
again by touching it with a wet brush. 
Variations in Shading. Variations in shading may be obtained 
easily by selecting the desired colors and mixing them separately, and 
on separate mixing slabs. The colors for the foundation, or gingival 
portion of the crown should be applied and built up to the desired point, 
after which the incisal, or occlusal color may be added without allowing 
the first to become completely dry. PORCELAIN CROWNS 
225 
Opoortunity for blending them as desired is afforded thus and very 
artistic results are possible, particularly in those cases where the base is 
to be yellow or brown, and the incisal or occlusal end blue or gray, in 
any of their variations. 
Carving and Contouring. When the moisture has been evaporated 
sufficiently, the paper matrix should be removed and the crown contoured 
and carved as desired. If not too dry, the procedure incident to contour- 
Fig. 197. 
ing and carving is quite simple, but the artistic results will depend much 
upon a knowledge of tooth form. 
This knowledge may be acquired easily by a close study of natural 
teeth, and a good plaster cast of a full typical arch will assist by serving 
as a guide in the execution- of this work. 
The requirements of occlusion and of approximal contact may be 
satisfied by trying the crown upon the casts frequently during the process 
of carving, and in order to prevent any flaking, or change of form, it 
may be moistened slightly with a wet brush previous to such trials. 
In carving and contouring, the porcelain must not overlap the shoulder 
at any point. And, previous to placing the crown in the furnace, all 
particles of body which may have become deposited upon the inside of 
the matrix should be removed carefully with a clean, dry brush to prevent 
it from becoming attached in fusing. 
The brushes used in this work should be of good quality such as are 
used in water-color painting, and three useful sizes and shapes are illus- 
trated in Fig. 197. The one of largest size always should be kept dry 226 
CROWN AND BRIDGEWORK 
and used only for smoothing up the surfaces, while the one of medium 
size should be used for the purpose of remoistening the body when neces- 
sary, and the smaller one only for deepening the finer lines in carving. 
Shrinkage. In contouring and carving a surplus is demanded by 
the shrinkage, which is estimated at one-sixth in all high-fusing com- 
pounds, but the exact shrinkage may be ascertained with accuracy only 
by a familiarity with the compound used. 
It is impossible to control or overcome shrinkage, and, hence, an 
allowance for shrinkage must always be made in building porcelain 
crowns. The foundation proportions, therefore, must be approximately 
one-sixth larger in every direction than the size desired and required in 
the finished crown. 
All porcelain compounds assume globular form if overfused, or when 
fused to a degree beyond that required to produce a vitreous surface. 
They begin to fuse on the surface and at the point where they are thinnest, 
and, hence, shrinkage begins at this point; but the shrinkage is in the 
direction of a common center, and the common center is at the point where 
the greatest thickness obtains. 
The thinnest point in a jacket crown is at the shoulder, and the plati- 
num matrix, being a good conductor of heat, fusion and shrinkage begin 
at this point. Therefore, when fusion begins, and as it progresses, the 
porcelain will draw away from the platinum matrix at the shoulder, and 
shrink toward the center. 
In order to prevent any distortion of the matrix which might be 
caused by the shrinkage at this point, and, in order to aid, rather than to 
retard shrinkage, it is always best to destroy any actual contact between 
porcelain and matrix at the shoulder before fusing. This precaution 
should be taken always and may be accomplished best by first slightly 
moistening the porcelain around the entire circumference at the shoulder, 
and inserting a very thin blade between it and the matrix at this point 
before fusing. 
When the carving has been completed, and when this and all other 
requirements have been met, the crown is then ready for the primary bake. 
Primary Bake. The crown should be detached from the amalgam 
cast carefully, and then placed in the furnace properly and baked until a 
vitrified surface presents, but complete vitrification should not be permitted 
at this time. 
Fusing to the point of the beginning of vitrification in the primary 
bake is necessary because of the desirability of securing a maximum degree 
of shrinkage at this time. PORCELAIN CROWNS 
227 
Final Bake. Usually the crown may be completed in two bakes. 
For the final bake, the body should be mixed thoroughly to a thin con- 
sistency, and first worked well down into every crevice and fissure caused 
by the shrinkage. Necessary restoration should be made until the desired 
contour is again obtained at all points. The crown then should be 
placed in the furnace and fused to the required degree of vitrification 
for the finished work. 
If, after this bake, the crown presents an irregular or broken surface, 
or if further additions are necessary, the same, or a lower-fusing body 
may be used and the crown fused again, though, if the proper precautions 
are taken, this seldom will be necessary. 
Fig. 198. 
Precautions Incident to Fusing. No portion of this work is of 
more importance than the baking or fusing of the body, because the 
strength of the porcelain and its true color are dependent upon its being 
fused properly. 
Supporting Crown in Furnace. When the crown is ready for the 
furnace, it must be adjusted to a suitable support which will allow it 
to rest firmly and evenly, and which will sustain it in a vertical position 
while in the furnace. It may be supported thus by means of a piece of 
platinum wire of suitable length, mounted in a base made of fireclay 
(Fig. 198), or it may be placed in a bed of coarse silex. 
Placing Crown in Furnace. In placing the crown in the furnace, 
it should be observed that it does not come in contact with the walls of 
the muffle, and it should be held in a vertical position in order to preclude 
any change of form which the influence of gravity might cause, if even 
slightly overfused. A design of pliers useful for this purpose has been 
illustrated previously in Fig. 26. 228 
CROWN AND BRIDGEWORK 
Heating Furnace. As a matter of expediency, the heating of the 
furnace should begin at some time during the building up of the crown, 
so that the muffle will be warm when the crown is ready for the baking. 
When this precaution has been taken, the support carrying the crown 
should be placed near the opening of the heated muffle and allowed to 
remain for a few moments, in order to become thoroughly dry, before 
it is placed inside of the furnace. This will preclude blistering the sur- 
face of the body, or the flaking of particles from the crown, as a result 
of the expansion of the remaining moisture, which would be induced by 
too rapid heating. 
In placing the crown in the furnace, it should be carried to a position 
as nearly in the center of the muffle as possible, or to that point where 
there are the greatest number of heat units. For the reason that the 
heat area varies in intensity to a considerable extent, it is seldom advisable, 
in the smaller muffles which have an opening in one end only, to bake 
more than one, or possibly, two crowns at a time; and, if each is to be 
baked uniformly, they must be placed crosswise in the center of the 
muffle, as the temperature increases toward the back and decreases toward 
the opening. 
Fusing. In fusing porcelain bodies, the physical process involved 
constitutes changing the powdered granular mass into a vitreous sub- 
stance, which then is homogeneous in proportion to the thorough admix- 
ture of the flux, or the degree of complete coalescence of all the particles. 
Hence, unless a pyrometer furnace is used, the proper fusing of these 
compounds is largely a matter of experience. In very low fusing bodies, 
the proper and desired degree of vitrification may be ascertained easily 
and definitely by observing this physical change as it is produced in the 
application of heat. This also is true of higher fusing bodies to some 
extent, but the greater degree of heat required, and the consequent in- 
candescence within the furnace, cause it to be more difficult. 
The eye may be trained to a degree of familiarity with the physical 
changes which will enable the experienced craftsman to distinguish more 
or less easily the disappearance of the rough or granular surface, and 
the appearance of the smooth, glassy, or vitreous surface, even in the 
somewhat trying glare of incandescent heat. With the majority of 
persons this may be done without greatly endangering or impairing the 
sight because it is not necessary to bring the eyes close enough to the 
furnace to be affected seriously by the heat, but smoked or colored glasses 
may be found useful for those who may fear impairment of sight. 
During the fusing of the body, the furnace may be opened occasionally, PORCELAIN CROWNS 
229 
and without danger to the porcelain, because the volume of heat units is 
too great to admit of the ingress of cold air. 
While any one desiring to do porcelain work in the most accurate 
and successful manner without a pyrometer furnace should cultivate this 
degree of familiarity with the characteristic appearance of the body in 
the various stages of vitrification, skill may be acquired only through 
experience. 
When the crown is placed properly in a furnace having no pyrometer, 
the heat should be increased gradually until a bright red color is produced. 
This may be done by degrees without observing the crown itself, but 
from this point on the fusing should be watched closely so as to observe 
when the rough and granular surface becomes smooth and vitreous, 
which, to the experienced eye, is indicated by the degree of incandescence 
reached, and as soon as a glassy appearance has spread over the entire 
surface of the porcelain, the heat should be discontinued immediately. 
Tests. Many tests for determining the exact heat required to fuse 
the various bodies properly have been suggested, but none is accurate or 
reliable. The use of pure gold will serve as a guide to the beginner, and 
as an aid to the experienced. A pellet of foil, or a small piece of plate 
placed beside the crown in the furnace will indicate when a temperature 
approximating 2016 degrees F. has been reached, by melting and assuming 
globular form. 
In fusing compounds, which fuse higher than pure gold, the heat 
required beyond this point is gaged by time, and some experimentation 
is required to ascertain the exact number of minutes and seconds beyond 
this point for the particular compound used. Pure gold, therefore, is 
helpful only to this extent. 
Pyrometer Furnaces. Any element of uncertainty, doubt, or danger, 
is overcome entirely, and certainty and accuracy in all cases are made pos- 
sible and insured by the use of the electric furnace with a pyrometer. 
Its use affords results which are true, scientific and accurate, and 
such results are desirable and necessary in porcelain work. If high fusing 
compounds are used, and if the best results obtainable are desired, the 
electric furnace must be used, and the pyrometer furnace should be used, 
to the exclusion of all other methods of heat production, and of accuracy 
in fusing. 
Cooling and Annealing. When the baking has been completed and 
the generation of heat has been discontinued, the furnace should be allowed 
to cool slowly. The crown never should be removed from the muffle 230 
CROWN AND BRIDGEWORK 
until cool enough to be held in the hand. This eliminates any danger of 
fracture, or brittleness, and so anneals the porcelain as to insure a maxi- 
mum of strength in the finished product. 
Final Requirements. When the crown has been removed from the 
furnace after the last baking, the surplus matrix should be trimmed away 
even with the porcelain at the shoulder. The crown then should be 
tried to place on its supporting root in the mouth. If any changes of 
Fig. 199. 
form are required they should be made at this time, and before the entire 
matrix is removed. 
If additions to the contact points, to the angles, or in length are de- 
manded, requiring another baking, such additions should be made and 
the crown baked again. 
If any desired change in form or outlines should necessitate grinding, 
the grinding should be done with clean carborundum stones of fine grit. 
Surfaces which have been ground should be polished highly with fine 
disks after grinding, and if any extensive grinding is demanded, the 
crown should be baked again. This is necessary, because a surface once 
ground never can be glazed again by polishing. 
Porosity. Porosity after baking is an unnecessary and discouraging 
calamity. It is due to one or the other of three different causes: To 
imperfect spatulation in mixing; to imperfect condensation in packing 
the body in forming the crown, or to overfusing. Imperfect spatulation 
and imperfect condensation are inexcusable, and overfusing must be 
avoided. PORCELAIN CROWNS 
231 
Overfusing. In the fusing of porcelain compounds, overfusing must 
be avoided. Strength and form and color in any of these products may 
be obtained only when the compound is fused properly, and never when 
it is overfused. 
Staining and Coloring. The characteristics of the remaining natural 
teeth may be reproduced, and grooves, pits and sulci may be tinted as 
desired by the use of mineral stains which are prepared for the purpose. 
Fig. 200. 
As these colors fuse at a lower heat than the porcelain body, however, 
this work is done to the best advantage after the crown has been com- 
pleted otherwise. When they are used for the reproduction of erosions, 
etc., on the labial or buccal surfaces, the desired inequalities first should 
be ground and formed with a small carborundum stone in the engine, 
and this outline tinted properly with the stains, or colors, and the crown 
then placed in the furnace again until the colors become vitreous. 
Grooves, pits, and sulci may be stained without grinding, and highly 
artistic results are possible. 
When all requirements of a finished product obtain satisfactorily, the 
crown then should be dipped in alcohol, or water, and the matrix removed. 
Mounting. In mounting porcelain jacket crowns, a cement, approxi- 
mating the color of the crown, should be used, and care should be exer- 
cised to avoid fracturing or chipping the edge in forcing it to place. 
After mounting, the joint between crown and supporting root always 232 
CROWN AND BRIDGEWORK 
should be finished down until smooth, using fine, narrow finishing strips 
for the purpose. 
Some idea of the possibilties of porcelain jacket crown restorations 
may be obtained from Fig. 199, and the restoration of the six upper 
anterior teeth in a case of typical Hutchinson teeth is illustrated in 
sequence in Fig. 200. 
Fig. 20i. 
Fig. 202. 
Use of Porcelain Teeth as Veneers. 
As a means of obtaining form, type and color with accuracy and cer- 
tainty, vulcanite teeth may he used instead of building and carving the 
crown entirely of porcelain. In the absence of suitable porcelain bodies, 
and in the absence of skill in selecting colors, and in reproducing form 
and type, this method of veneering the matrix, as suggested by Dr. E. B. 
Spaulding, is productive of good results. 
Porcelain teeth designed for vulcanite work are used, because of the 
advantage afforded by the lingual shoulder. (Fig. 201 A.) In their use 
for this purpose, a tooth which meets the requirements of form, type 
and color should be selected. The pins and the entire lingual surface 
should be ground away to the shoulder, until only a thin veneer presents. 
(Fig. 201 B.) PORCELAIN CROWNS 
233 
This procedure may be accomplished easily with small mounted stones 
of appropriate size and shape, kept wet while grinding. The grinding 
should be continued until the veneer fits over the matrix, as indicated in 
Fig. 201 C. 
When the desired adaptation has been obtained, the correct relation- 
ship between the veneer and the matrix should be sustained with tem- 
porary stopping (Fig. 201 D) and the two then removed from the cast. 
Then they should be adjusted to tweezers, or pliers, which will retain 
this relationship securely, while packing and carving the body to meet 
the requirements of form and contour. Soldering pliers having a lock- 
ing band are useful. A small piece of unvulcanized rubber should be 
placed between the veneer and one of the beaks as a means of holding the 
veneer securely, and to prevent it from slipping. The other beak should 
be carefully inserted inside of the matrix. (Fig. 202.) 
The two thus held securely, the temporary stopping should be warmed 
and removed, and the body applied, formed and carved as the require- 
ments may demand. When the carving has been completed the body 
should be allowed to become thoroughly dry, and the crown then removed 
from the pliers carefully, adjusted to position in the furnace properly, 
and fused. Two bakings usually will complete the crown. 
Porcelain in the Construction of Dowel Crowns 
Porcelain may be applied successfully to the construction of dowel 
crowns also. 
Restorations of this type are made with a platinum coping and a flat- 
back facing soldered to the coping. The body of the crown then is 
completed with porcelain. 
Indications. Crowns built in this manner are indicated wherever 
the esthetic requirements demand the use of porcelain, and wherever the 
dowel-crown type of construction, for any reason, may be preferable to 
the jacket crown. Porcelain dowel crowns, however, are not as strong 
as all-porcelain jacket crowns, and they possess but one advantage over 
the jacket crown. 
It is difficult, therefore, to conceive of any application in which the 
use of this type of crown might be preferable to a full all-porcelain restora- 
tion as a single unit. And, yet, when such crowns are built properly, 
they possess esthetic features combined with a degree of strength, quite 
adequate to the requirements of single unit restorations, and, being built 
upon a platinum coping, they also afford an esthetic means of attachment 234 
CROWN AND BRIDGEWORK 
for bridgework of any kind. This latter feature constitutes the one 
advantage. 
Requirements. To obtain such results with a maximum degree of 
strength, however, three essential requirements must be observed: 
First: The coping must be made strong enough to afford adequate 
strength in the attachment of the crown to its supporting root, and to 
support and protect the porcelain forming the body of the crown. 
Second: The facing must be adapted properly and attached securely 
to the coping. 
Third: The application of porcelain must be made only with a view 
to and for the purpose of meeting the requirements of form and esthetics. 
Coping. In order that adequate strength may obtain in the coping, 
a gage of platinum sufficiently thick to retain its shape and form must 
be used for all parts except the dowel. For this purpose the alloy of 
iridium and platinum is used because of the infusibility of platinum and 
of the additional strength imparted to it by the incorporation of a small 
proportion of iridium. 
Soldering. In soldering, perfect contact between all joints must ob- 
tain and a solder which will withstand the subsequent baking of the crown 
must be used. If absolute contact obtains, pure gold may be used as a 
solder, provided it is fused thoroughly, and until it practically becomes 
alloyed with the platinum. But if the greatest degree of strength is to 
be obtained, platinum solder, 25 per cent, should be used, and its use is 
absolutely necessary wherever contact does not exist. 
Should absolute contact not exist, and pure gold be used as a solder, a 
union which will withstand the heat of the blowpipe, or of the furnace, 
will not be secured. 
Oxyhydrogen Blowpipe. The oxyhydrogen blowpipe is necessary 
in the use of platinum solder, and also may be used to good advantage 
with pure gold. 
Root Preparation. The requirements of root preparation are the 
same as indicated previously for any of the various types of dowel crowns. 
The coping may be made either by the direct or the indirect method, 
and the details of procedure for each method are the same as indicated 
previously for dowel crowns. 
Adaptation is the basic requirement in the construction of copings 
for any type of crown restoration. Hence, when this requirement obtains, 
the particular method by which adaptation is secured is of but little im- PORCELAIN CROWNS 
235 
portance. A choice of methods, therefore, is a question largely of 
personal preference. 
Indirect Method. While platinum is not quite so soft and malleable 
as pure gold, still it may be swaged, or burnished, easily. Therefore, the 
indirect method may be used successfully. But in making a platinum 
coping by the indirect method, a thickness of plate as heavy as can be 
swaged, or burnished successfully, must be used, because it is not reen- 
forced subsequently to any appreciable extent. 
In order that adequate strength may exist in the coping itself, there- 
fore, when the indirect method is followed, pure platinum, 30 gage, 
Fig. 203. 
should be used, and never thinner than 32 gage. Platinum of this thick- 
ness may be swaged or burnished successfully and easily, thus insuring 
accuracy of adaptation; and it is heavy enough also to provide strength. 
While a full band, a partial band, or no band at all may be used, as 
the requirements of the case may indicate, the indirect method is ap- 
plicable more particularly to restorations where a partial band only is to 
be used. 
Direct Method. The direct method is indicated especially in cases 
where the requirements demand a full band, and a maximum of strength 
in the coping. 
Full Bands. Where a full band is to be used, it should be made 
of platinum (28 gage) and the edges should be overlapped. This pre- 
caution should be taken as a means of securing additional strength, and of 
precluding the subsequent opening of the joint from the exceedingly high 
degree of heat necessary to fuse the porcelain. The exact length of the 
measurement of the root should be designated on the surface of the plati- 
num plate from which the band is to be cut. A band of proper width 
then should be cut, with an allowance of about one millimeter surplus. 236 
CROWN AND BRIDGEWORK 
(Fig. 203 A.) Each end then should be slightly beveled on one side and 
the band annealed and bent into circular form. The surplus end, desig- 
nated by the measurement marking, should overlap the other end until 
the marking approximates evenly with this edge. (Fig. 203 B.) 
The surplus overlapping end must be placed on the outside to pre- 
vent diminishing the size of the band, and the relationship may be sus- 
tained by pinching the ends together closely with flat-nose pliers. This 
produces a sharp angle on each side of the joint and affords a flat surface 
contact. (Fig. 203 C.) This procedure usually will overcome any change 
in the relationship of the surfaces which might result from expansion 
when heated. 
The joint then should be soldered with 25 per cent platinum solder, 
or with pure gold, in the manner indicated. The band now should be 
trimmed to follow the gingival curvature, the edge nicely rounded and 
then fitted to the root. It afterward should be trimmed down until as 
narrow as possible, in accordance with the requirements mentioned. 
Floor. A piece of platinum about 32 gage now should be cut some- 
what larger than the diameter of the band. The band should be placed 
in position on it, and the relationship first simply tacked with a small bit of 
solder. This primary attachment secures the relationship and anneals 
the floor, so that it then may be burnished easily into close and direct 
contact with the edge of the band, without danger of changing the shape 
of the latter. 
The soldering now may be completed. If pure gold is used, it must 
be noted carefully that perfect contact exists at all points. After solder- 
ing, the surplus may be trimmed away and finished down until flush with 
the edge of the band. 
Dowel. The dowel should be made of iridio-platinum wire of a 
size proportionate with the size of the root and the requirements of 
the crown. It then should be fitted to the canal in the manner outlined 
previously. 
The coping now should be adjusted to position on the root, and the 
floor perforated at the proper point. The perforation then should be 
enlarged to the diameter of the dowel by forcing the dowel to place 
through it. 
This insures a perfect contact between floor and dowel, which is 
essential to the strength of the joint and to the facility with which the 
soldering may be accomplished. 
The relationship now should be sustained temporarily with hard wax, 
or temporary stopping, and the parts then removed, invested, and soldered. PORCELAIN CROWNS 
237 
Impression and Bite. When the coping has been completed, finished 
and adjusted to its proper position on the root, the bite then should be 
taken in wax and the impression in plaster. 
It should be observed that the coping rests firmly and accurately in 
place in the impression. The interior of the band and the exposed end 
of the dowel then should be painted with melted wax to facilitate its 
removal from, and to admit of its accurate replacement upon, the cast. 
Fig. 204 
This precaution is important, because of the necessity for trying the 
crown to place on the cast frequently during construction, and particularly 
in cases requiring restoration of contact and occlusion. 
Selection of Porcelain Facing. A flat-back porcelain facing, having 
platinum pins, should be selected carefully and should meet all require- 
ments of color, size and type. As the color is likely to be bleached slightly, 
instead of becoming darker, if some variation is necessary, it invariably 
should be darker rather than lighter. Porcelain teeth made of high-fusing 
porcelain retain their color and rarely change to any appreciable extent. 
But it is always necessary to use a body, the fusing point of which will 
not afifect the color of the facing. As an example, the use of high-fusing 
body in combination with English facings (Ash and Sons) will destroy 
the color entirely. 
In grinding the facing, the edge of the coping should be nicely rounded 
previously with disks. (Fig. 204 A.) The facing then should be ground 
to overlap the labial, or buccal, surface of the coping, in order to prevent 
undue prominence at this point. (Fig. 204 B.) 
This overlapping is necessary as a means of bringing the gingival edge 
of the facing into close proximity with the gingival tissue. It is neces- 
sary also for the purpose of affording a mechanical retention to the porce- 
lain with which this portion of the band should be covered. 
If the band is not covered entirely upon this surface, it always will 
show through the thin, transparent, gingival tissue and cause a dark blue 
appearance at this point. 238 
CROWN AND BRIDGEWORK 
This discoloration is a decidedly undesirable feature, and since there 
is no physical union between porcelain and platinum, the overlapping of 
the facing affords a secure mechanical retention for porcelain, sufficient 
to cover this portion of the band, and to present a smooth, flush joint in 
the finished crown. 
Wherever it is desirable to retain porcelain in contact with a surface 
of platinum, some means of mechanical retention is always necessary. 
Fig. 205. 
Fig. 206. 
Increased mechanical retention may be obtained by allowing a very slight 
space to exist between facing and coping. (Fig. 204 C.) 
When the facing has been adapted properly, its relationship to the 
coping should be sustained with adhesive wax, and coping and facing 
then detached from the cast and invested. The finished crown, showing 
the possibilities of contour, strength and esthetics, is illustrated in Fig. 
204 D. 
Investment. In investing, only enough investment to sustain the 
relationship and to afford sufficient strength should be used, and when 
the investment compound has crystallized, all surplus should be trimmed 
away until the entire lingual surface of the facing is exposed freely. 
(Fig. 205.) 
A free exposure is necessary as a means of facilitating soldering, and 
it may obtain without danger of fracturing the facing, if the case is heated 
adequately before attempting to solder. PORCELAIN CROWNS 
239 
Soldering Facing. Before heating the case, the pins should be bent 
down toward the facing until their ends may be brought into absolute con- 
tact either with the dowel or with the coping. This bending may be done 
by holding the facing firmly in place with a blunt instrument, and then 
applying sufficient pressure to the extreme ends of the pins to bend them 
into the relationship desired. It is desirable always to bend the pins down 
close to the facing and thus afford more space for the porcelain. 
Anterior Crowns. In anterior crowns, the pins should be bent down 
close to the facing until their ends are brought into direct contact with the 
Fig. 207. 
Fig. 208. 
surplus end of the dowel at a point as close to the floor of the coping as 
possible. (Fig. 206 A), or, until they are in direct contact with the floor 
itself. (Fig. 206 B.) 
This feature of construction is important because it affords the same 
degree of strength in the attachment of the facing to the coping and 
adds to the strength of the finished crown. Otherwise the pins would 
divide the porcelain through the center and interfere with the proper and 
desired contour of the lingual surface. 
In cases where the ends of the pins will not reach to the floor, or to the 
dowel, the space should be filled in with platinum plate, or wire, until 
contact is secured as illustrated in Fig. 206 C. The finished crown, show- 
ing the possibilities of contour, strength and esthetics is illustrated in 
Fig. 206 D. 
Leaving Pins Exposed. Another variation of construction con- 
sists in bending the pins down until their ends come in contact with the 
floor, and then filling in between them with platinum solder, and subse- 
quently making no effort to cover them with porcelain. (Fig. 207.) 
Bicuspid Crowns. Since there is no physical union between the 
porcelain and the platinum, in the construction of bicuspid crowns it is 
not only desirable to make as much accommodation for the porcelain 
which is to form the entire lingual contour of the crown as possible, but 240 
CROWN AND BRIDGEWORK 
it also is necessary to provide some means for mechanically retaining and 
supporting it. 
Adequate mechanical support to the porcelain may be obtained best 
and most easily by soldering a narrow strip of platinum plate, about one 
millimeter in width, to the floor of the coping on a line even with the 
edge of the band. This addition should be fitted before heating the case, 
and should be attached at the time of soldering the facing. It thus forms 
a box-like support for the porcelain. (Fig. 208 A.) 
Fig. 209. 
Fig. 210. 
This method of construction is applicable to incisor, cuspid and molar 
crowns, as well as to bicuspid crowns. The finished crown is illustrated 
in Fig. 208 B. 
Reenforced Coping. Inherent strength in the coping itself is a 
prerequisite in this class of work. Therefore, the increased strength to 
be obtained by reenforcing the coping in the manner previously suggested 
as applicable to the construction of dowel crowns, often may be used to 
advantage. 
This increased strength is to be secured by allowing the floor to project 
slightly beyond the band upon the mesial, distal and lingual surfaces, and 
then filling in the shoulder so formed with platinum solder (25 per cent) 
until smooth and flush, as illustrated previously in Fig. 147. 
Molar Crowns. In the construction of molar crowns, two methods 
may be followed. One embraces the use of a facing, as described in the 
construction of bicuspid crowns, and the other consists of making the 
coping and building the entire crown of porcelain without the use of a 
facing. 
With Facing. While it is true that the requirements of color are 
not quite so important in molar restorations, yet the use of a facing often 
is indicated as a means of obtaining form and color. 
When a facing is used, the details of construction are the same as 
indicated for bicuspid crowns. (Fig. 209 A.) The finished crown is 
illustrated in Fig. 209 B. PORCELAIN CROWNS 
241 
Without Facing. In cases where the requirements of occlusion de- 
mand a very short restoration, the use of a facing may be contraindicated, 
and the best results obtained by making a simple coping and forming the 
entire crown with porcelain. In such cases the porcelain must be sup- 
ported by a boxing or housing around the entire circumference, which, 
together with the finished crown, is illustrated in Fig. 210. 
Fig. 21 i. 
Fig. 212. 
Additional mechanical attachment of the porcelain to the coping may 
be secured by roughening the surface of the platinum with a sharp-pointed 
instrument, or by soldering small loops made of round platinum wire. 
Partial Band. Where only a partial band is required, and where the 
direct method of construction may be preferable to tbe indirect method, 
for any reason, a platinum coping may be made in the manner indicated 
previously for dowel crowns with partial bands, combined with an observa- 
tion of the requirements for porcelain work. 
The band should be made of 28 gage, and the floor of 32 gage plati- 
num and the structural requirements for porcelain work, together with 
the completed crown, are illustrated in Fig. 211. 242 
CROWN AND BRIDGEWORK 
Without Band. In the construction of porcelain dowel crowns with- 
out a band, the adaptation of the floor, or basal portion of the coping, may 
he made successfully either by swaging or burnishing, and pure platinum, 
about 32 gage, should be used. The structural requirements and the 
completed crown are illustrated in Fig. 212. 
Casting Porcelain. Efforts directed toward casting porcelain have 
been made and are being made. Success would revolutionize porcelain 
work, much as casting gold has revolutionized all other restorative and 
reparative procedures. Hence, the advent of casting porcelain success- 
fully will be welcomed. Principles and Technics of 
Fixed Bridgework 
CHAPTER XIV. 
BRIDGEWORK. 
Perhaps nowhere in the human economy is the mystifying ingenuity 
of the Creator evidenced more wonderfully than in the masticatory 
mechanism. 
And when it embraces a full complement of sound, healthy, normally 
posed single units, perfectly coordinated, it is not within the realm of 
human endeavor, nor within the province of art to reproduce, much less 
to improve upon, the original plan. 
In the original plan the loss of any one single unit probably was 
never anticipated. That this is true, is evidenced in the eruption of the 
third molars, which, appearing after all other teeth, after the period of 
adolescence, and after complete development, majestically close and lock 
the arches. 
History teaches, however, that from the beginning of civilization the 
human family has suffered the loss of teeth, and that efforts toward the 
replacement of missing teeth were made many years before the Christian 
era. 
While it is probable that the primitive efforts in the replacement of 
missing teeth were made for the purpose of esthetics alone, it is recog- 
nized now that esthetics constitutes but one indication for restoration, and 
that restoration of function is even of greater importance. 
It is recognized now that once this wonderfully coordinated mechanism, 
the dental arches, is disturbed, it never again will be physiologically per- 
fect ; that the loss of even a single unit unlocks the interrelationship of 
the whole, and that any derangement is followed by impairment of normal 
functioning activities. And it is recognized further that any impairment 
of the normal functioning activities of the teeth is followed by a lowering 
of the tonicity, health and resistance of their investing and environmental 
tissues. 
243 244 
CROWN AND BRIDGEWORK 
Therefore, it is evident that when either of the dental arches has been 
disturbed by the loss of one or more units, the missing units must be 
replaced in order that normal health may be restored, and in order that 
normal balance may be maintained. 
The replacement of missing teeth, however, is always a problem of 
serious portent, because it means that the remaining teeth, or the environ- 
mental tissues, or both, must bear the burden of assuming the function 
of the missing unit, or units, in addition to the requirements incident 
to their own normal activities. 
And as the extent of impairment and the degree of additional burden 
increases in proportion to the number of units lost, and which must be 
replaced, it will be observed that an intrinsic value should be placed upon 
each and every single unit in the normal denture. 
A recognition and an appreciation of these important considerations 
always should encourage a conscientious effort to avoid impairment of 
normal function, and of overburdening of remaining teeth, and, thus, to 
contribute to health, to comfort, and to longevity by conserving the 
natural teeth. 
The maintenance of normal conditions and the conservation of health, 
therefore, places a responsibility upon the shoulders of all who are in- 
clined honestly and conscientiously; and this responsibility should en- 
courage an effort to save the natural teeth under all favorable conditions. 
And yet, however zealously such effort may be made, until such 
time as preventive dentistry shall have become a realization, teeth will 
be lost. 
They will be lost as they have been lost, because of neglect, disease or 
accident, or by virtue of the ravages of time and use, habits and foods, 
and largely because of failure to recognize and appreciate their value. 
When they are lost from any of these causes they must be replaced, 
and when they are replaced, the replacement must be made in a manner 
which will cause the least injury to the remaining natural teeth, and 
which will insure the maximum of efficiency and of permanency in the 
restoration of function. 
The replacement of missing teeth, therefore, is an art. It is an art 
which occupies an important place in the field of prosthetic dentistry, or 
prosthodontia. 
Prosthetic dentistry, or dental prothesis, defined, means the art of 
restoring lost dental organs and associated parts with an artificial 
substitute. 
Prosthodontia, defined, means a restoration of the teeth by means of 
an artificial substitute, or substitutes. The term, prosthodontia, thus BRIDGEWORK 
245 
limiting the restoration to the teeth alone is not entirely comprehensive, 
and, hence, has not been accepted generally. 
Previous to the advent of the specialty of crown and bridgework, miss- 
ing teeth were supplied by means of partial dentures made of gold or 
silver, and, later, of vulcanite, covering the hard palate, or the underlying 
tissues, and retained by adhesion only. 
Fig. 213 
The introduction of clasps followed. This means of retention was 
such an improvement over adhesion alone that the supporting base was 
made smaller and smaller. It soon was discovered, however, that partial 
clasp dentures may be injurious to the crowns of supporting natural 
teeth, and the base itself, irrespective of its size, may be injurious to the 
health and normal relationship of the gingival tissues around the re- 
maining natural teeth. 
Then came a resurrection of the ancient method of supplying missing 
teeth by attachment to remaining natural teeth, and the introduction of 
modern fixed bridgework followed. This seemed to offer so many fea- 
tures of advantage over former methods that it soon came into general 
use, and was applied indiscriminately. 
The possible advantages of supplying missing teeth by a fixed attach- 
ment to remaining natural teeth, and of avoiding, thus, the wearing of 
any type of removable structure, which appealed at once to the wearer, 
were buried soon under an avalanche of indiscriminate and injudicious 
application, with the result that the requirements of health, hygiene and 
sanitation were ignored, and failure followed. 246 
CROWN AND BRIDGEWORK 
The irreparable injury done to sound teeth, together with a failure 
to observe the requirements of health, hygiene and sanitation, could be 
expected only to result in failure. And, notwithstanding the myriad of 
methods and devices which were introduced from time to time, failure 
was recorded in a large percentage of cases. 
Fig. 214. 
As a means of obtaining increased opportunities for an observation 
of the important requirements of health, hygiene and sanitation, the 
introduction of removable bridgework followed, and innumerable methods 
and devices for the construction of structures of this type also have been 
presented from time to time. 
Removable bridgework, however, is susceptible equally to indiscrimi- 
nate and injudicious application, and is not a panacea for all defects 
and faults to be found in other methods. 
Both fixed and removable bridgework have passed through the experi- 
mental stages. Each has done much damage and has caused the loss of 
many good teeth. The failures, however, were attributable more largely 
to overenthusiasm, to indiscriminate application and to faulty technic, 
than to incorrect principles. 
Typical cases showing a flagrant indifference to the requirements of BRIDGEWORK 
247 
strength in fixed bridgework, and an indifference which could only invite 
and result in failure, are illustrated in Fig. 213. And typical cases show- 
ing an indifference to the requirements of stress in the application of 
removable bridgework which could only invite and result in failure are 
illustrated in Fig. 214. 
Methods. 
In the replacement of missing teeth there is no one best line of pro- 
cedure, and no one best method. The conditions and requirements are so 
varying, and the highest possibilities are so exacting that no one line of 
procedure, and no one method possesses a range of application sufficiently 
broad to meet the demands of universal usefulness. 
Nearly all of the accepted methods and practices of today have a 
place, a range of application, and a field of usefulness, when selected with 
intelligent discrimination, and good judgment, and when the application 
is made skilfully. 
To use intelligent discrimination in the selection of the particular 
method of procedure which seems adapted best to the case at hand, de- 
mands that one must be familiar, first, with all methods and must know 
the advantages and disadvantages of each. One must be a keen observer 
of cause and effect also, and must possess an unprejudiced judgment, to a 
degree which will result in the selection of the particular method by 
which he can obtain the best results. 
The physiologically ideal method of replacing missing teeth is not yet 
within the range of the most hopeful vision, and until such time as the 
ideal procedure in all cases is possible, all methods of replacement must 
be but a choice of evils. 
Classification. 
In all cases where any number of natural teeth remain, in either 
arch, the replacement of missing teeth may be effected successfully by 
any one of three different methods, namely: fixed bridgework, removable 
bridgework and clasp dentures. 
Whenever the number and distribution of the remaining natural teeth 
is favorable, and where teeth favorable to the requirements in all respects 
may be used for the purpose of attachment and support for the structure 
which is to supply the missing teeth and afford the restoration required, 
fixed or removable bridgework may be used. But where the number 
and distribution of the remaining natural teeth is unfavorable to the 
physiological and mechanical requirements of bridgework of any type, 
then a clasp denture is indicated. 248 
CROWN AND BRIDGEWORK 
Fixed Bridgework. Fixed bridgework embraces that type of fixture 
which is designed to be attached securely and permanently to the abutment 
teeth which support it. It thus becomes a fixed part of the denture. 
And becoming a fixed part of the normal denture, the requirements of 
hygiene and sanitation demand that no part of the structural formation 
ever should cover the subjacent mucosa. 
Removable Bridgework. Removable bridgework embraces that type 
of structure which is designed to rest firmly upon the subjacent mucosa 
and which is held in place by some means of retaining attachment, and 
where the retaining attachment itself assumes the entire burden of the 
stress imposed, affords fixation and stability when in position, and yet 
admits of removal and replacement without destroying the integrity of 
any of the parts. 
In the structural formation of removable bridgework, some form of 
“saddle” resting firmly upon the subjacent mucosa always must supple- 
ment the retaining attachment. The use of a saddle adds strength to the 
body of the structure, stabilizes its retention, and admits of restoration. 
Type. In the construction either of fixed or removable bridgework, 
the type varies with the requirements of the case, but all cases may be 
classified as simplex, compound, complex and cantilever in type. 
Simplex. Bridgework of the simplex type may be either anterior or 
unilateral, and involves the replacement of one or two teeth and never 
more than three teeth of similar functional activity. 
Compound. Bridgework of the compound type may be either an- 
terior, unilateral, or antero-posterior, and involves the replacement of 
more than two teeth, and of teeth of different functional activity. 
Complex. Bridgework of the complex type may be antero-posterior, 
or bilateral, and embraces the replacement of any great number of teeth 
of different functional activity in one structure. 
Cantilever. Bridgework of the cantilever type may be unilateral, 
antero-posterior, or anterior, and embraces that type in which positive 
fixation obtains at one end only, and where a simple rest, or a support 
in the form of a flexible or movable joint obtains upon the other end. 
Assemblage. The application and construction of all forms of fixed 
or removable bridgework involve the assemblage of abutments, attach- 
ments and pontics. 
Abutments. The natural teeth which are used for the purpose of 
attachment, and which afford retention and support to the structure, are 
known as the abutments. BRIDGEWORK 
249 
Attachments. In fixed bridgework the mechanical agency which is 
used to attach the fixture to the abutment, whether it be full crown, a 
partial crown, an inlay or any variation of these types, is known as the 
attachment. 
Retaining Attachments. In removable bridgework of any kind, the 
mechanical agency which is to support and retain the structure in its 
relation to the abutment, and which admits of removal and replacement 
is known as the retaining attachment. 
Pontics. The artificial substitutes for the missing natural teeth, which 
form the intermediaries between or adjacent to the attachments, are 
known as pontics. 
Requirements. 
In the application and construction of bridgework of any type, certain 
physiological and mechanical requirements must _ obtain and be observed 
always. 
Physiological. The physiological requirements demand: 
First: That a state of health exist in the teeth which are to be used 
for abutments, and in their investing and environmental tissues. 
Second: That normal conditions be reproduced and simulated as 
closely as possible. 
Third: That the adaptation of all attachments to all abutments be 
made in a manner which will preclude mechanical irritation and which, 
therefore, will not invite pathological changes. 
Mechanical. The mechanical requirements demand: 
First: That all abutments be prepared properly to receive and accom- 
modate the attachments, and to withstand the influences of stress. 
Second: That all attachments possess strength adequate to the re- 
quirements of stress, and that all requirements of occlusion should be 
adequately met. 
Third: That the structural outlines should be adapted to all require- 
ments and that adequate inherent strength to support the pontics while 
functioning should obtain. 
Fourth: That the pontics be so formed and so shaped as to meet 
the demands of strength, sanitation, and esthetics to the highest degree 
possible. 
Occlusal Stress. 
A knowledge of the influence of stress in mastication is one of the 
most important basic requirements incident to the successful application 250 
CROWN AND BRIDGEWORK 
of any form or type of bridgework. While cases requiring the replace- 
ment of missing teeth rarely ever present with absolutely normal occlusion, 
still, even if they did, the same knowledge would be-essential. 
Incision, prehension and trituration are the functions of the teeth of 
mammals. These activities obtain as a result of the opposing forces of 
the mandibular teeth against the maxillary teeth. The direction in which 
the teeth move in functioning varies with the teeth brought into play, 
and the stress imposed upon the anterior teeth in incision, or upon the 
cuspids and first bicuspids in prehension, or upon the second bicuspids 
and molars in trituration, is not the same either in direction or in intensity. 
In incision the forces expressed drive the upper incisors upward and 
outward, and the lower incisors downward and outward. 
In prehension the forces expressed drive the upper cuspids outward 
and slightly upward, and the lower cuspids inward and slightly down- 
ward. The forces of stress received by the upper bicuspids drive them 
upward, outward and backward, while the lower bicuspids are driven 
downward, inward and slightly forward. The upper molars are driven 
outward, backward and upward, while the lower molars are driven inward, 
backward and downward. 
All of the teeth yield to stress in these directions first, but in assuming 
their normal positions again, they, of course, move back, or in the opposite 
direction. 
Thus they move continually, as stress is initiated or released, and all of 
these conditions must be observed in order that they may be accommodated. 
Traumatic Occlusion. The influence of trauma upon the investing 
tissues in restorations of any type must always receive careful considera- 
tion. 
Traumatic occlusion includes abnormal occlusal stress which is 
capable of producing, or has produced an injury to the periodontium. 
This is a condition which exists frequently, and often is not recognized 
until too late. It may occur in cases in which a full complement of 
natural teeth is present; and it is found, almost invariably, whenever the 
dental arch is weakened by the loss of one or more teeth. Therefore, it 
may be found in all classes of cases and under all conditions. 
Traumatic occlusion obtains whenever one tooth strikes the opposing 
tooth, or teeth, with more force than the other teeth strike. And the 
greatest injury is not produced so much in the act of mastication, where 
the stress is cushioned by food, as it is by direct contact of tooth upon 
tooth, as in swallowing. In the act of swallowing it has been estimated 
that from three to eight pounds of stress is imposed. BRIDGEWORK 
251 
In bridgework, if the supporting teeth are normal and healthy, the 
opposing teeth will respond to traumatic occlusion before it manifests in 
the supporting teeth themselves. Hence, if traumatic occlusion exists 
in the natural teeth, it may be produced by a simple filling, by a crown, 
or by a restoration of any type. And when this condition is discovered 
it must be corrected. 
In the application and construction of bridgework, therefore, all the re- 
quirements of functional occlusion must be carefully accommodated, and 
Fig. 215. 
every effort should be made to avoid traumatic occlusion. And no restora- 
tion, whether fixed or removable, ever should be inserted, nor ever will 
be successful unless functional occlusion obtains. Whether it be a single 
crown or a bridge of the most complex type, every precaution must be 
taken to avoid traumatic occlusion, and to insure a restoration of normal 
function. 
A carbon paper known as “articulating paper” is prepared for this 
purpose and always should be used as a means of checking up and finally 
perfecting the construction to meet occlusal requirements. 
Phonation. 
The structural design in any and in all of its details, and irrespective 
of whether fixed or removable, must be made in such manner as to offer 
no appreciable impediment to correct speech. 
A dental restoration of any type must offer no interference with normal 
enunciation and this will obtain only when normal outlines are reproduced, 
and when the conformation and adaptation are favorable. 
Combination Fixed and Removable Bridgework. 
Various methods of combining the advantages both of fixed and re- 
movable structures in a single appliance have been suggested. Many of 
the suggestions are ingenious, but all of them are more or less intricate, 
and none of them ever has been accepted as a useful method of procedure. 
Generally, appliances of this type embrace adjustable retaining at- 252 
CROWN AND BRIDGEWORK 
tachments which, when placed in position on the supporting teeth, are 
then locked with a small screw. (Fig. 215.) This admits of removing, 
cleansing and replacing the appliance at intervals sufficiently close to in- 
sure some degree of sanitation. 
The psychological aspect of the possibilities of sanitation, however, 
is the only feature of advantage possessed by this type of construction, 
and it never has been used extensively. The best results are obtained 
from the use of an appliance which either is fixed definitely and positively, 
or which is removable definitely and easily. 
Clasp Dentures. 
Clasp dentures embrace that type in which the subjacent soft tissues 
support the body of the denture and assume the burden of the stress im- 
posed, the clasps acting as a retaining medium only, except where the clasp 
is supplied with an occlusal rest, in which case the burden is shared by 
the abutment teeth. 
The application and construction of clasp dentures do not belong 
properly to bridgework, yet this type of construction is associated closely 
with removable bridgework. Clasp dentures are indicated and often used 
in preference to removable bridgework because of greater simplicity, and 
because the application requires no preparation, and, therefore, less 
immediate destruction of the abutment teeth. 
Selection of Methods. 
In the selection of the method which seems best adapted to the case 
at hand, it must be remembered that conditions vary to such an extent 
that no mechanical device which is designed to become a part of the 
human economy is applicable universally. 
Each case presenting must be studied carefully from the viewpoint of 
the foundation, first, and the requirements of health, hygiene, occlusion and 
stress must be considered before the selection can be made intelligently. 
And when the selection has been made, it must be made conscientiously 
and with a view to accomplishing the replacement, not in the simplest man- 
ner, nor by the easiest method, but in the best manner and by the method 
best for the case in hand. 
“The thing easiest to do rarely is done well,” is a truism applicable 
to bridgework, because any method used in the replacement of missing 
teeth is not easy if the highest achievements are to obtain. CHAPTER XV. 
FIXED BRIDGEWORK. 
Modern fixed bridgework has been a common feature of practice for 
many years. The possible advantages that may be obtained from the re- 
placement of missing teeth by means of an attachment fixed to remaining 
natural teeth were recognized early, and were alluring. 
“Teeth without plates” became a psychological magnet, and many were 
carried away on a wave of enthusiasm. As a result, all other methods of 
replacing missing teeth, except in edentulous cases, were forgotten tem- 
porarily by many, and the virtues of fixed bridgework were championed 
and extolled to a point beyond the limits of reason. 
Those were pioneer days, however, and the methods were pioneer 
methods. The application met with varying degrees of success and fail- 
ure. 
Some, overenthusiastic, used fixed bridgework to the exclusion of all 
other methods. Those who did, soon encountered failures. The more con- 
servative, however, soon recognized possible disadvantages, and possible 
reasons for failure. They made an effort to eliminate or to minimize both, 
and to use this method, not to the exclusion of all others, but where it 
seemed to be a rational procedure. 
Others, who were less analytically inclined, were so influenced by the 
percentage of failures, as to become discouraged, and, ultimately, criticized 
and even condemned fixed bridgework in whole and in part. 
The criticism and condemnation, however, have been productive of 
much good, and have reacted in such manner as to revolutionize former 
methods of practice, and to place the skilful application of modern fixed 
bridgework in its proper place, as one of the useful methods of replacing 
missing teeth. 
The use of fixed bridgework to the exclusion of all other methods of 
replacing missing teeth was a practice that justified criticism and con- 
demnation. 
Like any other one method of procedure, this one is not universally 
applicable. And, like all other methods that may have an elastic range of 
application and an extensive field of usefulness, it has been abused. And 
when any method is abused by indiscriminate, overzealous and incompetent 
application, criticism must follow, and condemnation often is warrantable. 
253 254 
CROWN AND BRIDGEWORK 
Heretofore, fixed bridgework has been a mass of empirical methods, 
applied indiscriminately. Possible injury to the supporting natural teeth, 
and the requirements of hygiene and sanitation have been ignored largely. 
Both considerations are vital issues always. The conservation, promotion 
and maintenance of health must be the fundamental consideration in the 
replacement of missing teeth by any method. And the application of 
any method which does not involve and include favorable possibilities 
in these directions is to be regarded as approaching the border line of 
malpractice. 
In the application of fixed bridgework, therefore, the conservation of 
the health of the supporting natural teeth is the first consideration, and 
hygiene and sanitation follow closely as basic requirements. 
A certain amount of injury to the supporting natural teeth must follow 
the replacement of missing teeth by any method, irrespective of whether 
the restoration be of the fixed or the removable type. But unless the 
partial immobilization of the supporting natural teeth which follows the 
application of fixed bridgework, in itself, is absolutely detrimental to the 
health and vitality of the teeth so treated, then no greater injury results, 
necessarily, from one method than from another. 
Fixation as a Principle. 
The “fixation,” or the partial immobilization of natural teeth which 
follows the application of fixed bridgework, therefore, is a consideration 
of importance, theoretically and physiologically, at least, because nothing 
quite analogous is attempted otherwise, or, in so far as is known, is tol- 
erated by Nature. 
Biology teaches that “the function of normal tissues in organs at work 
cannot be violated seriously, without impairing the vitality of the organs 
involved.” In the partial immobilization of the natural teeth, the normal 
functioning movements are restricted necessarily, and, to a degree, an 
abnormal condition is established. But whether the limited restriction of 
movement, or the establishment of a condition which is not physiologically 
ideal, will invite or produce a pathological condition, is doubtful, and is 
not proven by clinical evidence so far. 
It is true that Nature does not tolerate absolute fixation, nor abso- 
lute immobilization, of any tissues in the body which move in functioning, 
and that where this condition obtains indefinitely, degeneration and atrophy 
follow. And it is true, too, that all movable tissues require a certain 
amount of exercise and stimulation in order that health may be promoted 
and maintained. FIXED BRIDGEWORK 
255 
Also it is true that teeth move in functioning and that a reasonable 
amount of exercise and stimulation is essential to the health of their in- 
vesting and environmental tissues. And it is true also that inflammation 
begins with stasis, and that prolonged stasis of circulation, at any given 
point, will be followed by degeneration and atrophy. 
These biological principles apply to the teeth as well as to other tissues, 
and, doubtless, would obtain and follow in sequence if the teeth were to be, 
or if they could be, immobilized absolutely and permanently. But the teeth 
are not entirely analogous with any other tissues in the body. They are 
cushioned peculiarly by their investing tissues, and they are cushioned in 
such manner, and by tissues of such character, and of such tolerance, as to 
make complete and absolute immobilization practically impossible. 
As a strictly hypothetical proposition: If the full complement of teeth 
in either arch were to be banded first as single units, and if the bands were 
assembled into one major fixture, and this fixture then cemented to place 
upon the teeth, absolute fixation, or complete immobilization, would not 
obtain. Some movement, even though restricted, and limited, and far 
from normal, would be possible because of the character and resiliency of 
the investing tissues. 
A lowered tonicity and resistance of these tissues would follow, of 
course, but, so long as some degree of normal functioning activity were 
possible, a pathological condition would not be invited, necessarily. 
Therefore, if complete and absolute immobilization of the teeth prac- 
tically is impossible, and if the investing and environmental tissues will 
tolerate partial immobilization, then fixed bridgework is a rational and use- 
ful method of supplying missing teeth, and its application often may be 
indicated as the choice of evils, or as the lesser evil. 
Clinical evidence, extending over a period of many years, indicates be- 
yond a reasonable doubt, that the degree of immobilization which follows 
the application of well designed, and well built, and properly adapted fixed 
bridgework does not condemn teeth, necessarily, nor condemn the vitality 
of their pulps, nor invite a pathological condition. 
And it is noteworthy to observe, too, that pulpless teeth are tolerated 
under these conditions quite as well as are teeth having vital pulps; also, 
that partial immobilization, instead of insuring an impairment of the vi- 
tality and usefulness, and the ultimate loss of teeth so treated, on the con- 
trary, frequently adds to their usefulness and longevity. 
Indeed, teeth which have lost the support and protection previously af- 
forded by adjacent and opposing teeth, where the investing tissues are 
of low tonicity, and where usefulness and comfort are negative, often may 
be made comfortable and serviceable for many years by stabilizing them. 256 
CROWN AND BRIDGEWORK 
In many instances of this kind partial immobilization is not only not injuri- 
ous, and not destructive, but is a positive restorative measure. 
Therefore, while it cannot be claimed that a physiologically ideal condi- 
tion follows the application of fixed bridgework, and while it is apparent 
that a semi-, or a quasi-abnormal condition obtains, still it is evident that 
Nature does and will tolerate a partial immobilization of the natural 
teeth, and that teeth so immobilized, with all other conditions made favor- 
able, may and do remain healthy and serviceable for many years. 
Like collateral circulation, and like the accentuation of the remaining 
senses following the loss of one, and like many other physiological phe- 
nomena, these clinical truths afford only another evidence of the resource- 
fulness of Nature. 
Advantages. In the replacement of missing teeth by any method 
the aim should be: First, to obtain a maximum of efficiency in the restora- 
tion of function; and, second, to obtain this maximum of efficiency with 
a minimum of injury to the supporting natural teeth. 
Functional efficiency increases with stability and decreases with mo- 
bility. Flence, in proportion as any type of restoration is stabilized in 
functioning, its efficiency will be increased. Absolute fixation, therefore, 
insures the maximum of stability. 
In addition to the important feature of increased efficiency, the modern 
methods of attachment require less destruction of the supporting natural 
teeth for fixed bridgework than is required for any type of removable 
bridgework, other than clasp dentures. 
Indications. Fixed bridgework is indicated and may be used suc- 
cessfully, whenever the application may be made under favorable condi- 
tions and within reasonable limitations. 
Favorable conditions mean that health must obtain, primarily, in all 
teeth which are to be used as abutments; and reasonable limitations mean 
that a knowledge of the basic laws of mechanics, or of dynamics in particu- 
lar, must obtain, and must be applied in each and every case. Irrespective 
of however well fixed bridgework may be built and adapted, no case will 
be successful unless sound mechanical principles are followed through- 
out its construction and application. 
The ideal and most typical indications for the use of fixed bridgework 
embrace: 
First: those cases where only a few teeth are to be replaced in a single 
fixture: and, second, those cases where teeth of similar functional ac- 
tivities only are included in the same fixture. 
While it is not imperative that only teeth of similar functional activi- FIXED BRIDGEWORK 
257 
ties should be included in a single fixture, a more typically physiological 
condition obtains, undoubtedly, whenever the normal functioning move- 
ment of the supporting natural teeth is restricted to a minimum extent, 
rather than to a maximum extent. 
In grouping the teeth of similar functional activity, the four incisors 
and cuspids, moving in the same general direction in functioning, may be 
linked together and designated as Group No. i. The bicuspids and molars, 
moving in the same general direction in functioning, may be linked to- 
gether and designated as Group No. 2. The most ideally successful 
results will be obtained when the dental arches are divided thus into three 
segments, each segment embracing and including only teeth of similar 
functional activities, as follows: 
Group No. 1. Any combination of abutments and attachments which 
is confined to the six anterior teeth, exclusively. 
Group No. 2. Any combination of abutments and attachments which 
is confined to unilateral groups embracing the bicuspids and molars only. 
The distribution of the abutment teeth in either group is important, 
and, usually, the number of abutment teeth should be equivalent to the 
number of missing teeth to be supplied. This rule is not imperative, how- 
ever, because the strength of the abutment teeth in their relation to the re- 
quirements of stress is the controlling factor in all cases. 
Clinical evidence proves conclusively that the teeth will withstand and 
will tolerate a burden of stress in excess of normal functional demands. 
But the extent to which they may be expected to assume this additional 
burden, and the duration of expected toleration, must be within the limits 
of reason. 
Under favorable conditions one tooth will do the work of two teeth, 
but to do the work of two teeth, the abutment tooth must be supported or 
protected against the influence of excessively abnormal stress. This is an 
imperative rule in all cases. The simplest application of this rule may be 
made in the replacement of a single missing tooth by attachment to a single 
abutment. 
Supplying Missing Teeth. 
Supplying a Single Missing Tooth. A single abutment will sup- 
port a single pontic, only under favorable conditions, and favorable condi- 
tions demand: First: that the abutment tooth be the larger and stronger; 
and, second, that it must be protected against the influence of the addi- 
tional and abnormal stress to which it will be subjected. 
In supplying a single pontic by attachment to a single abutment, the 258 
CROWN AND BRIDGEWORK 
abutment acts as the fulcrum and the pontic becomes a lever. Hence, the 
power of the lever is exerted upon the abutment tooth at all times. As 
a result of the continued influence of stress, increased by the power of the 
lever, the abutment tooth will yield, and it will yield in the line of least 
resistance. 
In the posterior teeth, this line of least resistance is toward the eden- 
tulous space. Posterior pontics, therefore, must be supported against 
stress in the line in which the preponderance of stress is received, which 
is in a vertical direction. Hence, posterior pontics must be supported 
against vertical stress. 
In the anterior teeth, where the roots are of conical formation, usu- 
ally, yielding to the line of least resistance, the influence of stress would 
result in an outward and rotary displacement of the upper teeth, and in 
an inward and rotary displacement of the lower teeth. Hence, a sus- 
pended anterior pontic must be supported against lateral stress, or stress 
which would result in torsion, or in the rotation of the abutment tooth on 
its long axis. 
Therefore, in supplying a single posterior pontic by attachment to a 
single posterior abutment, an extension resting into or upon the occlusal 
surface of the natural tooth, adjacent to the pontic, is necessary always 
and when adjusted properly will support the abutment tooth adequately 
against both vertical and lateral stress. 
The same provision must obtain in the anterior teeth also and all an- 
terior abutments to which pontics are suspended must be protected against 
torsion, or rotation, on their long axes. A simple rest upon the lingual 
surface of the natural tooth adjacent to the pontic will meet the require- 
ments in this respect. 
These mechanical requirements must be provided in all cases where a 
single pontic is suspended from a single abutment, except, perhaps, in 
cases where the first molar is used to support a missing second bicuspid. 
The normal size and stability of the first molar in such cases, as compared 
with the size and requirements of the second bicuspid, do not make 
such provisions imperative in all cases, though the strain upon the abut- 
ment tooth would be lessened and the efficiency of the pontic increased, 
if this provision is supplied even in these cases. 
Supplying Two Missing Teeth. In supplying two missing teeth, 
two abutments are necessary in all cases, irrespective of whether the teeth 
to be replaced are adjacent to each other, or are separated by one of the 
abutment teeth. 
The most typical fixed bridgework is that type which is attached to FIXED BRIDGEWORK 
259 
abutments at each extreme end, however large or however small the fixture 
may be, but this typically favorable condition is not imperative. It is 
not imperative because when the distribution is favorable, one pontic may 
be suspended. But a suspended pontic must be suspended anteriorly of 
the first molar and anteriorly of its attachment to the abutment tooth. 
This rule is imperative because the maximum of occlusal stress centers 
in the first molar, and diminishes proportionately with each tooth anterior 
thereto, and because no suspended pontic should be placed where it will 
be subjected to a degree of stress exceeding the stress imposed upon and 
assumed by the supporting abutment. 
Anterior Teeth. In replacing two anterior teeth the attachments 
must be securely fixed to the abutment teeth in all cases. 
Posterior Teeth. In the replacement of posterior teeth, either a 
fixed attachment at both ends or the cantiliver type of fixture may be 
used successfully. 
Cantilever Type. A fixed attachment at one end and a movable 
joint at the other end of small posterior fixtures often is advantageous, 
but the possible advantages and usefulness of this type of construction are 
limited to cases in which one, and never more than two, pontics are sup- 
plied. 
Because of the difiference in the normal functioning activities of the 
cuspids and the first bicuspids, the cantiliver type of construction often may 
be used to advantage in fixtures which involve these particular teeth. 
A movable joint between cuspid and first bicuspid, when it may be 
supplied without weakening the fixture, is a physiologically ideal type of 
construction because of permitting the abutment teeth to function inde- 
pendently of each other, but it is not imperative that a movable joint should 
be placed at this point in all cases. 
As an example: A missing cuspid may be supplied successfully by at- 
tachment to the first bicuspid alone. And a missing lateral incisor and a 
missing first bicuspid may be supplied by attachment to the cuspid and sec- 
ond bicuspid in a single fixture, and with or without a movable joint be- 
tween the cuspid abutment and the bicuspid pontic. 
Field of Usefulness. 
VVith the preceding fundamental principles as a basis, the range of ap- 
plication and the field of usefulness of fixed bridgework, of each of the 
four basic types, may be classified as follows: 260 
CROWN AND BRIDGEWORK 
Fig. 216. 
Fig. 217. 
Fig. 218 FIXED BRIDGEWORK 
261 
Fig. 219. 
Fig. 220. 
Fig. 22i. 
Fig. 222. 262 
CROWN AND BRIDGEWORK 
Simplex Type. 
The range of application of fixed bridgework of the simplex type 
embraces all small fixtures involving teeth of similar functional activities, 
mainly, as classified previously in Groups No. 1 and No. 2. 
Group No. 1. 
Class i.—Replacing Missing Central Incisor. In replacing a miss- 
ing central incisor (Fig. 216 A), the pontic should be supported both by 
mesial and distal attachments, each fixed to the abutment teeth. (Fig. 
216 B.) 
A fixed attachment to the adjacent central incisor alone, together with 
a simple rest upon the lingual surface of the lateral incisor (Fig. 217), 
might answer the purpose in some cases, but a maximum degree of sta- 
bility and permanency would not be obtained in this manner. 
Any type of attachment to the central incisor alone would be entirely 
inadequate in either arch. 
Class 2.—Replacing Missing Lateral Incisor. A missing lateral 
incisor (Fig. 218 A) may be supported adequately by attachment to the 
cuspid (Fig. 218 B) or to the central incisor, (Fig. 218 C) only, but in 
either case a lingual rest must be placed aganist the tooth not used as an 
abutment. 
Rotation of the abutment tooth on its long axis invariably would follow 
a failure to observe this precaution, and a misalinement of the pontic, as 
indicated in Fig. 219, soon would result. 
A definite fixed attachment both to the central incisor and the cuspid, 
as illustrated in Fig. 220, however, is entirely unnecessary. Either one of 
the abutment teeth is sufficiently strong to support the missing lateral 
incisor, when a provision against rotation is made; therefore, a simple 
rest against the tooth not used as an abutment would answer the purpose 
of fixation, and offer no interference with the normal functioning move- 
ment of either tooth, which would be advantageous. 
Class 3.—Replacing Missing Central Incisors. In replacing the two 
central incisors (Fig. 221 A) a secure fixed attachment to the two lateral 
incisors (Fig. 221 B) will prove adequate in most cases, where the con- 
ditions of occlusion are favorable. Owing to the relative weakness of 
the roots of the lateral incisors, however, a successful and permanent 
fixture will obtain only when these conditions are favorable. FIXED BRIDGEWORK 
263 
Fig. 223. 
Fig. 224. 
Fig. 225. 
Fig. 226. 264 
CROWN AND BRIDGEWORK 
Fig. 228. 
Class 4.—Replacing Missing Lateral Incisors. Missing lateral 
incisors (Fig. 222) may be replaced successfully, by either of one or two 
methods of procedure. First, a fixed attachment to the two central incisors 
will support the laterals in a more or less secure and permanent manner. 
(Fig. 223 A.) And, second, a fixed attachment to each cuspid, with a 
simple lingual rest against the central incisors, thus making two inde- 
pendent fixtures, will answer the purpose. (Fig. 223 B.) 
A choice between these procedures should depend upon the presence 
of caries, fillings, or other defects in the crowns of the teeth to be used 
as abutments, and those having defects of any kind should be used in 
preference to good, sound teeth in all cases. 
Class 5.—Replacing a Missing Central and Lateral Incisor. A 
missing central and lateral incisor, adjacent to each other (Fig. 224 A), 
may he supported successfully by a fixed attachment to the cuspid and 
central incisor. (Fig. 224 B.) 
When the missing central and lateral incisors are not adjacent to each 
other (Fig. 225 A), the attachment should be made to the remaining cen- 
tral and lateral incisors, in which case it is not necessary to include or 
involve either cuspid. (Fig. 225 B.) FIXED BRIDGEWORK 
265 
Fig. 229 A. 
Fig. 229 B. 266 
CROWN AND BRIDGEWORK 
Fig. 230. 
Fig. 231. 
Class 6.—Replacing Missing Central and Both Lateral Incisors. 
The two cuspids and one remaining central incisor (Fig. 226 A) will 
support the missing central and two lateral incisors successfully. The 
presence of the intervening central incisor will stabilize the fixture and 
insure permanency. (Fig. 226 B.) 
Class 7.—Replacing Missing Centrals and One Lateral Incisor. 
The two cuspids and one lateral incisor also will support the missing 
centrals and lateral successfully. The compound anchorage at one end 
also stabilizes the fixture and insures success. (Fig. 227.) FIXED BRIDGEWORK 
267 
Fig. 232. 
Fig. 233. 268 
CROWN AND BRIDGEWORK 
Class 8.—Replacing Missing Four Incisors. The four incisors 
(Fig. 228 A), upper or lower, may be replaced successfully by a fixed 
attachment to both cuspids (Fig. 228 B), and the strength and stability 
of the cuspid teeth insures a more or less permanent fixture usually. 
The most satisfactory results are obtained, however, in cases where 
any great overlapping of the upper teeth upon the lower teeth does not 
present (Fig. 229 A), but where an incisal relationship, which is more 
nearly end to end obtains. (Fig. 229 B). As a means of preventing an- 
terior protrusion, this relationship should obtain whenever possible. 
Class 9.—Replacing Missing Cuspid. A first biscuspid will support 
a missing cuspid successfully. (Fig 230 A). While the first bicuspid is 
a good, strong, and well-balanced abutment, usually, still a lingual rest 
upon the adjacent lateral incisor is a safe precaution against misalinement. 
(Fig. 230 B.) 
Class 10.—Replacing Missing First Bicuspid. The cuspid will 
support a missing first bicuspid (Fig. 231 A) successfully in favorable 
cases, provided that no effort to restore the occlusal surface of the pontic 
is made. (Fig. 231 B.) If occlusal restoration is demanded, a fixed 
or a movable attachment to the second bicuspid must be supplied. 
The suspension of a first bicuspid pontic from a cuspid abutment is 
classified in Group No. 1 because the cuspid tooth, which belongs in this 
group, is involved, principally. 
Group No. 2. 
Class i.—Replacing Missing First Bicuspid. A missing first bicuspid 
may be replaced in the best and most permanent manner by means of a 
fixed attachment to the second bicuspid. 
The conical formation of the root of the second bicuspid, however, 
demands a rest against the lingual surface of the cuspid as a provision 
against rotation and displacement. (Fig. 232.) This provision must be 
supplied in all cases, and at all times, and as a further means of diminish- 
ing the stress necessarily assumed by the abutment in these cases, the 
politic never should possess a full occlusal surface restoration. 
Any appreciable amount of restoration of the occlusal surface of first 
bicuspid pontics is never necessary. These particular teeth assume but a 
minimum of actual masticatory stress, normally, and as a rule, the pontic 
used in effecting the replacement never should be required to assume any 
great burden of stress. 
Class 2.—Replacing Missing Second Bicuspid. The first molar will 
support the second bicuspid successfully where no attempt is made FIXED BRIDGEWORK 
269 
Fig. 234. 
Fig. 235. 270 
CROWN AND BR1DGEWORK 
Fig. 236. 
to restore the occlusal surface of the second bicuspid pontic. (Fig. 233.) 
If occlusal restoration is demanded, then either a fixed or a movable 
attachment to the first bicuspid must obtain. 
Class 3.—Replacing Missing First Molar. In the replacement of a 
missing first molar, the requirements of stress are so great that both 
mesial and distal attachments must be used in all cases. (Fig. 234.) 
The attachments may be both fixed, involving the simplex type, or a 
fixed attachment at one end and a movable attachment at the other end, 
thus involving the cantilever type, may be used, and either will be suc- 
cessful. 
If any appreciable advantage may be obtained from not interfering 
with the independent movement of the abutment teeth, the application of 
the cantilever type would be typically applicable in this class of cases. 
Class 4.—Replacing Missing First Molar and Second Bicuspid. 
A second molar and a first bicuspid will support the intervening second 
bicuspid and first molar successfully because all teeth involved in this 
class of cases are of similar functional activity; and, because of the length 
of the fixture and the burden of stress which the pontics must assume, the 
best results will be obtained from a fixed attachment at each end. (Fig. FIXED BRIDGEWORK 
271 
FlG; 237. 
Fig. 238. CROWN AND BRIDGEWORK 
272 
Fig. 239. 
Fig. 240. FIXED BRIDGEWORK 
273 
235-) This type of fixture is the simplest application of the simplex 
type of construction to Group No. 2. 
Class 5.—Replacing Missing First Molar and First Bicuspid. 
A missing first molar and first bicuspid may be replaced successfully 
by a fixed attachment to the second molar and second bicuspid. (Fig. 
236.) This also is a typical application of the simplex type of construc- 
tion to cases classified in Group No. 2. 
Class 6.—Replacing Missing First and Second Molars. A third 
molar and a second bicuspid will support the intervening first and second 
molars successfully and this also is a typical application of the simplex 
type. (Fig. 237.) But owing to the burden of stress assumed by the 
pontics, the best results will result from absolute fixation at both ends of 
the fixture. 
Class 7.—Replacing Missing Second Molar and Second Bicuspid. 
The third molar and the first molar will support the second molar and 
second bicuspid, and is a typfcal application of the simplex type also. 
(Fig. 238.) The best results in this application of the simplex type also 
will result from a continuous fixture. 
Compound Type. 
Fixed bridgework of the compound type dififers from the simplex 
type only in so far as involving teeth of different functional activity, and 
may be applied successfully to the following classes of cases: 
Class 1.—Replacing Missing Lateral Incisor and First Bicuspid. 
A missing lateral incisor and first bicuspid (Fig. 239 A) may be sup- 
plied successfully by attachment to the cuspid and second bicuspid. (Fig. 
239 B.) In this application a movable joint between the cuspid and first 
bicuspid may or may not be used. A movable joint at this point may be 
advantageous in some cases, but even though the abutment teeth are of 
different functional activities, successful results will follow the applica- 
tion of a continuous unbroken fixture in the average case. The central in- 
cisor and cuspid could be used successfully also, in which case the fixture 
would belong to the simplex type. (Fig. 239 C.) 
Class 2.—Replacing Missing Cuspid and Second Bicuspid. A 
missing cuspid and second bicuspid (Fig. 240 A) may be replaced suc- 
cessfully by attachment to the lateral incisor and first bicuspid (Fig. 
240 B), provided that no restoration of the occlusal surface of the second 
bicuspid pontic is attempted. 
If occlusal restoration of the second bicuspid pontic is desirable, or is 274 
CROWN AND BRIDGEWORK 
Fig. 241. 
Fig. 242. FIXED BRIDGEWORK 
275 
Fig. 243. 
Fig. 244. 276 
CROWN AND BRIDGEWORK 
Fig. 245. 
Fig. 246. FIXED BRIDGEWORK 
277 
Fig. 247. 
necessary, then attachment to the first molar must be made. And when 
attachment to the first molar obtains, no attachment to the lateral incisor 
is necessary. (Fig. 241.) 
Class 3.—Replacing Missing Cuspid and First Bicuspid. A miss- 
ing cuspid and first bicuspid (Fig. 242 A) may be supplied successfully 
by attachment to the lateral incisor and second bicuspid (Fig. 242 B), 
but owing to the inherent weakness of both abutment teeth, this affords 
probably the weakest type of compound fixture. Hence it must be made 
in one continuous fixture at all times, and even then will be of doubtful 
permanency. 
Class 4.—Replacing Missing Bicuspids (Unilateral). The two 
bicuspids on either side of the arch (Fig. 243 A) may be supported suc- 
cessfully by attachment to the cuspid and first molar. (Fig. 243 B.) 
Even though teeth of different functional activities are involved, success 
is insured in the application of this type of case because of the normal 
strength and stability of the abutment teeth. 
Class 5.—Replacing Missing Lateral Incisor and Both Bicuspids. 
A missing lateral incisor and both bicuspids on one side of the arch 
(Fig. 244 A) also may be supplied successfully by attachment to the 
cuspid and first molar. (Fig. 244 B.) The normal strength and stability 278 
CROWN AND BRIDGEWORK 
Fig. 248. 
of the cuspid and first molar are adequate to the additional requirements 
of the lateral incisor pontic thus suspended. 
Class 6.—Replacing Two Bicuspids and First Molar. The first 
molar and both bicuspids (Fig. 245 A) also may be supplied successfully 
in one fixture by attachment to the cuspid and second molar. (Fig. 245 B.) 
This involves a longer fixture and a somewhat weaker abutment at the 
posterior end, but under favorable conditions a successful application 
may be made. 
Class 7.—Replacing Bicuspids and First and Second Molars 
(Unilateral). In cases where the two bicuspids and first and second 
molars are missing (Fig. 246 A) on one side of the arch only, they may 
be supplied by attachment to the cuspid and third molar. (Fig. 246 B.) 
Such cases, however, will overburden the abutment teeth to the extreme 
limit; hence, the replacement of these teeth usually is best effected by 
means of some form of removable bridgework. Restoration of lost tissue, 
also, usually is required in these cases, and such restoration demands the 
use of a removable structure at all times. 
Class 8.—Replacing Missing Lateral Incisor, Bicuspids and First 
Molar (Unilateral). The most complex application of fixed bridgework 
of the compound type would involve the replacement of the lateral incisor, FIXED BRIDGEWORK 
279 
Fig. 249. 
bicuspids, and first molar (Fig. 247 A) by attachment to the central in- 
cisor, cuspid and second molar in one unilateral fixture. (Fig. 247 B.) 
The application of a fixture of this size might be made successfully under 
very favorable conditions, but because of its extensiveness, a removable 
fixture would be a safer and preferable procedure in most cases. 
Complex Type. 
The complex type of fixed bridgework embraces all forms of bilateral 
fixtures in which the replacement of missing teeth on both sides of the 
arch in one single fixture is involved. 
Class i.—Replacing Missing Incisors and Cuspids. In replacing 
the six anterior teeth (Fig. 248 A) the first bicuspids alone will not 
support the intervening cuspids and incisors successfully in any form of 
fixed bridgework. But the first bicuspids, together with any one of the 
intervening cuspids or incisors (Fig. 248 B), will support the remaining 
anterior teeth successfully when the requirements of occlusion are favor- 
able. (Fig. 248 C.) 
Class 2.—Replacing Missing Incisors and First Bicuspids. The 
second bicuspids and the cuspids (Fig. 249 A) frequently will support 
the missing incisors and first bicuspids successfully. (Fig. 249 B.) This 
type of fixture is approaching the limitations of successful fixed bridge- 280 
CROWN AND BRIDGEWORK 
Fig. 250. 
Fig. 251. 
work very closely and almost to the borderline of reason, but its applica- 
tion may be successful in cases in which all conditions are favorable. 
Class 3.—Replacing Missing Incisors, Cuspid and First Bicuspid. 
The second bicuspids, together with two other anterior teeth (Fig. 250 
A), will support the remaining missing anterior teeth, provided the FIXED BRIDGEWORK 
281 
Fig. 252. 
Fig. 253, 
distribution of the abutment teeth is favorable to a more or less equal 
distribution of stress. (Fig. 250 B.) The entire success of fixtures of this 
type will depend upon the careful observation of basic mechanical prin- 
ciples in their application, and unless the conditions are favorable to all 
requirements, a removable structure should be used. 282 
CROWN AND BRIDGEWORK 
Class 4.—Replacing Missing Lateral Incisors, Cuspids and Bi- 
cuspids. Missing lateral incisors, cuspids and bicuspids (Fig. 251 A) 
may be supported successfully by attachment to the two central incisors 
and the two first molars. (Fig. 251 B.) The supporting teeth, how- 
ever, would be overburdened, and the practicability and permanency of 
the fixture would be so doubtful as to indicate some type of removable 
structure. 
Fig. 254. 
Class 5.—Replacing Missing Incisors and Bicuspids. The cuspids 
and first molars, normally, are the strongest teeth in the arch. Hence, 
under the most favorable conditions they will support the missing incisors 
and bicuspids more or less successfully and more or less permanently. 
(Fig. 252.) Fixtures of this type, however, are the extreme limit in the 
application of fixed bridgework, and such application should be made only 
in cases where the requirements of restoration of lost tissue are negative, 
and where every other condition is favorable. Otherwise, a removable 
structure is demanded. 
Class 6.—Variations. Any variations in the distribution of the abut- 
ment teeth, such as is illustrated, for example, in Fig. 253, will not effect 
the successful application of fixtures of the complex type materially, 
provided that the distribution is favorable to the basic mechanical re- 
quirements. 
Cantilever Type. 
The cantilever type of fixture is indicated and used most frequently in 
the replacement of missing first molars and first bicuspids. 
Class i.—Replacement of Missing First Molars. In the replace- 
ment of missing first molars, a secure attachment to the second molar, 
and some form of simple movable joint which will sustain both vertical FIXED BRIDGEWORK 
283 
and lateral stress in the attachment to the second bicuspid will meet all 
requirements, (hig. 254.) Each abutment then may move to a degree 
independent of the other while functioning. And if any advantage obtains 
from some increased mobility, it is obtained easily in this manner without 
diminishing the efficiency of the politic. 
Class 2.—Replacement of Missing First Bicuspids. The cantilever 
type of fixture also is useful in cases which involve several teeth of differ- 
ent functional activity. A movable joint between the cuspid and first 
bicuspid affords the advantage of permitting the abutments to move some- 
what independently of each other in functioning. (Fig. 255.) This ad- 
vantage never must obtain at the expense of strength and efficiency, 
however. 
Fig. 255. 
Interrupted Fixtures. 
A type of construction, known as an “interrupted” fixture, is used 
sometimes in cases where a single good tooth remains intermediate to the 
teeth to be used as abutments and the pontics to be replaced, and where 
the number and distribution of the abutment teeth is favorable to the re- 
quirements, without using or in any manner involving the remaining tooth. 
It is, of course, never advisable to use more teeth than necessary to 284 
CROWN AND BRIDGEWORK 
insure stability, efficiency and permanency. Hence, in cases of this type, 
there is a temptation to conserve all good teeth not actually needed in 
meeting the requirements, and to build the fixture qround such teeth. 
This is accomplished by making the fixture in segments and joining, or 
uniting, the segments with heavy plate or wire. Round iridio-platinum, or 
clasp-metal wire, about 16 gage, is generally used for this purpose, and it 
is placed to the lingual of the remaining tooth, and just free from contact 
with it and the mucosa. (Fig. 256.) 
Fig. 256. 
This type of construction presents two objectionable features: First, 
even though the wire is not in actual contact with the tooth, or with its 
surrounding tissues, such fixtures are not sanitary; and second, the wire 
is an impediment to speech, usually. Therefore, as a rule, it would be 
better either to build two separate fixtures, or to include and involve the 
intermediate tooth. 
Extension Fixtures. 
Previous to the application of fixed bridgework along the more mod- 
ern and more rational lines now practiced, a type of construction known as 
“extension” bridgework was used. Fixtures of this type involved a saddle 
extending from the fixture proper, and resting upon the mucosa, as a 
means of supporting one or more suspended pontics. (Fig. 257.) 
Because of the yielding character of the subjacent soft tissue as com- 
pared with the resistance offered by the abutment teeth, the entire burden 
of stress assumed by such extensions must be supported by the abutment 
teeth alone, and this burden is increased proportionately by the power 
of the lever. FIXED BRIDGEWORK 
285 
Hence, irrespective of the number, distribution and original stability 
of the abutment teeth, all pontics supported by an extension, which is 
fixed at one end only, are not to be regarded as efficient restorations, nor 
is this type of fixture to be regarded as one which subscribes to the basic 
requirements of sanitation to an extent which would give it a place of use- 
fulness among modern methods of procedure. 
Fig. 257. 
Saddle Fixtures. 
A saddle resting firmly upon the subjacent mucosa and incorporated as 
a part of the structural formation of fixed bridgework was used more or 
less extensively at one time. 
This type of construction was used as a means of increasing the struc- 
tural strength of the fixture, and of effecting the restoration of lost tis- 
sue ; and it was claimed that if the saddle is shaped properly and adapted 
closely the fixture will be sanitary; but no greater fallacy ever was pro- 
mulgated. 
When any form of saddle resting upon the subjacent mucosa is used in 
fixed bridgework, capillary stasis and congestion follow, and health and 
sanitation are impossible. Hence the use of a saddle of any form or size 
never is indicated and is not to be regarded as a rational procedure in the 
modern application of successful fixed bridgework. 
Requirements. Primarily, fixed bridgework embraces an assemblage 
of attachments and pontics into one continuous fixture which is cemented 
to place upon its supporting abutment teeth. It therefore becomes a fixed 
part of the dental arch, and if the best results are to be obtained, the 
requirements are exacting and must be satisfied. 
Adaptation. Adaptation, essentially, is the first requirement. Hence, 
the adaptation of all attachments to their supporting abutment teeth, and 286 
CROWN AND BRIDGEWORK 
of all pontics to the subjacent mucosa must be of such character as to pre- 
clude the possibility of mechanical irritation. 
Strength. Since no fixture can be stronger than its weakest part, 
inherent strength adequate to meet the requirements of stress in each 
and every part of fixed bridgework of any type always must exist. Any 
deficiency in this direction only invites failure. 
Attachments. As a means of conserving health by precluding the 
possibility of mechanical irritation, all attachments, whether they are full 
crowns, partial crowns, inlays or any variations of either, must be adapted 
closely. Accuracy of adaptation means absence of mechanical irritation, 
and absence of mechanical irritation means health, comfort and perma- 
nency. 
Pontics. For esthetic reasons, all anterior pontics must be placed in 
close contact with the subjacent mucosa, but posterior pontics never should 
be placed in closer contact than the esthetic requirements demand; and as 
a means of providing further against mechanical irritation, the gingival 
edge of all pontics must be blunt, round and smooth. And all pontics 
should be of such shape and form, and should be placed in such relation- 
ship with the tissues and with each other, as to insure proper sanitation. 
Hygiene and Sanitation. The problem of hygiene and sanitation is 
an important consideration in the replacement of missing teeth by any 
method. A failure to recognize and to appreciate the requirements in this 
connection has been a common practice and has been the cause of much 
criticism and condemnation of fixed bridgework. Generally, it has been 
justifiable. 
That fixed bridgework may be a menace to health, and that a countless 
number of good teeth have been lost through misuse and abuse is unques- 
tionable. Unsanitary conditions, in the main, are to be attributed to two 
general causes, however. First, to faulty adaptation of the attachments 
to the abutments; and second, to faulty structural formation. 
Accuracy of adaptation is possible, and a type of structural formation 
favorable to sanitation is possible, also, but when an observation of these 
features, combined, is not possible, then fixed bridgework is not indicated. 
Structural Formation. Anterior pontics, being of more favorable 
shape, usually are more susceptible of hygienic care than posterior pon- 
tics; hence, posterior pontics should be as nearly convex in form, bucco- 
lingually and mesio-distally as possible, and never should be larger 
bucco-lingually than the actual requirements of usefulness demand. This 
precaution will reduce inaccessible surfaces and will make it easier to ob- FIXED BRIDGEWORK 
28; 
serve hygienic care. Also, all interproximal spaces between the pontics 
themselves, and between pontics and attachments, must be sufficiently large 
to insure sanitation, and no form of saddle resting upon the subjacent 
mucosa ever should be used. 
Instructions to Patients. If these requirements and precautions are 
observed carefully, and if the patient then is given proper instructions as 
Fig. 258. 
Fig. 259. 
to the necessity for hygienic care, and is taught how it may be obtained, 
fixed bridgework may be kept as sanitary as the natural teeth themselves 
may be kept. 
Paralleling Abutments. In the successful application of fixed 
bridgework, two or more teeth are to be linked or bound together with a 
single fixture. Hence, all abutment teeth must be prepared properly, not 
only as single unit abutments, but also along mutually parallel lines. 
Parallelism of the axial surfaces of all abutment teeth, therefore, is an 
important and necessary consideration and must obtain in all cases and 
at all times. (Fig. 258.) 
If parallelism does not obtain, accuracy of adaptation of attachments 
is impossible, and an unnecessary and often injurious strain is placed upon 
the roots of the abutment teeth. And, unduly forcing abutment teeth out 
of normal position invariably will invite a pathological condition. 
When this requirement has been met properly, fixed bridgework will 
go to place readily, without appreciable effort and without strain. And 288 
CROWN AND BRIDGEWORK 
the requirements are the same in all cases irrespective of the type of ah 
tachment to be used, as illustrated typically in the use of a dowel crown 
and a telescope crown in a single fixture in Fig. 259. 
Radiographic assistance always is essential and the use of a paralleling 
instrument, or even of simple calipers, will aid appreciably in meeting the 
demands of this requirement. 
Articulation and Occlusion. The efficiency, comfort and permanency 
of fixed bridgework demand that the requirements of articulation and oc- 
clusion be met with exactness, and exactness demands accurate casts and 
Fig. 260. 
a careful study of the occlusion, in order that the pontics may be articu- 
lated so as to meet the requirements of functional occlusion when in use. 
One of the commonest errors made in the construction of fixed bridge- 
work is a failure to meet the requirements of stress in relation to the 
resistance offered by the abutment teeth. The direction in which the 
greatest and the least resistance is offered must be noted, and the occlusion 
so adjusted as to conform closely thereto. 
In this connection it must be remembered that the abutment teeth will 
withstand vertical stress to the degree indicated, but that undue lateral, or 
antero-posterior stress lessens the stability, usefulness and permanency 
of the fixture which they support. 
Therefore, the depth of the cusps and the adjustment of the relation- 
ship between the opposing teeth must provide for accommodation for the 
various excursions of the occlusal surfaces in functional occlusion. 
If the long axes of the abutment teeth are along parallel lines, as il- 
lustrated in Fig. 260, any antero-posterior movement is mutual, and, hence, 
not especially injurious; but if the long axes of the abutment teeth are 
not parallel, one with the other, one will receive stress in line with its 
greatest resistance, and the other in line with its least resistance. In such 
cases the attachments should be adjusted to meet the requirements of 
each abutment tooth separately first, and the pontics then formed in such 
manner, and placed in such relationship with the opposing teeth as to 
permit the abutment teeth to assume the burden of stress at all times. FIXED BRIDGEWORK 
289 
A proper formation of the cusps in such cases means that they should 
not be deep, and should not interdigitate appreciably, nor interlock to any 
degree; and also that they should be no wider bucco-lingually than ab- 
solutely necessary to provide some degree of usefulness. 
Opening the Bite. Whenever the teeth in either arch are deprived of 
their normal relationship with the opposing teeth, elongation follows, is 
inevitable, and often results in an exasperating condition. 
Fig. 261 
Elongation. This condition frequently demands correction, and cor- 
rection often requires that the bite be opened, and that a new relationship 
between the opposing surfaces of the maxillary and mandibular teeth be 
established, before any type of useful restoration may be made. 
When such conditions are encountered, accurate impressions and casts 
of all remaining teeth in both arches should be obtained and mounted 
upon an articulator. By careful study, the extent to which the bite should 
be opened then may be determined definitely. When the extent to which 
the bite should be opened has been determined, certain teeth upon each side 
of the arch which seem best adapted to the requirements incident to estab- 
lishing the new closure, or relationship, should be selected. 
The teeth selected then should be built up, or down, first as single units, 
by some means of permanent restoration. If the permanent restoration 
is to become a part of some type of fixed bridge work, the fixture should 
be completed and all restorations used in establishing the new relationship 
should be mounted at the same time. A typical case of elongation and the 
possibilities of restoration is illustrated in Fig. 261. 
Grinding Natural Teeth. In cases of elongation, frequently it is ad- 
visable and often necessary to grind the occlusal, or the incisal surfaces 290 
CROWN AND BRIDGEWORK 
of elongated teeth. A reasonable amount of grinding is permissible wher- 
ever it may be indicated, provided that the surface ground is polished 
smooth after grinding. 
In this connection, if the precaution of polishing smooth after grind- 
ing is observed carefully, the incisal ends of anterior teeth often may be 
ground until true and even without injury, and often to good advantage 
from the viewpoint of esthetics. 
Fig. 262. 
Fig. 263. 
Wherever it may be necessary to grind the crowns of natural teeth to 
a point which leaves the dentin exposed to any great extent, the insertion 
of a simple filling may be indicated as a means of precluding caries. 
Abrasion. Opening the bite is demanded frequently in cases of 
abrasion also. In such cases the desired relationship of the opposing 
teeth should be established first, by means of occlusal restorations, in the 
form of pin-locked inlays. These should be made for the teeth selected 
as single units first, after which they may be assembled, if assemblage 
is desired or necessary. 
Occlusal restorations which are used for the purpose of opening the 
bite, whether used as single units, or assembled into one fixture, never FIXED BRIDGEWORK 
291 
should be mounted finally until the new relationship is sustained by teeth 
on both sides of the arch, and by more than two teeth on each side, when- 
ever possible. 
The greater the number of opposing natural teeth which are involved 
in the initial procedure incident to the establishment of a new relation- 
ship, or to the restoration of the original relationship between the maxillae 
and mandible, the less discomfort will be occasioned, and as some slight 
temporary discomfort follows opening the bite in nearly all cases, the 
preliminary precaution of using several teeth in the initial operation 
should be observed always. 
Fig. 264. 
Iridio-platinum, or high-fusing clasp metal wire, 19 or 20 gage, is 
used for the pins in forming pin inlays. The inlays may be made either 
by the direct or the indirect method, and care must be exercised in placing 
and in drilling the holes in the natural teeth in order to avoid pulp ex- 
posure, and to insure parallelism. 
A simple case of pin inlays used for the purpose of opening the bite 
in cases of abrasion is illustrated in Fig. 262, and a more extensive case 
in Fig. 263. The full possibilities in an extensive case of abrasion before 
and after opening the bite is illustrated in Fig. 264. 292 
CROWN AND BRIDGEWORK 
Construction. 
The construction and application of fixed bridgework involves an as- 
semblage of attachments and pontics. The attachments to the supporting 
natural teeth are the retaining agencies and, hence, they are essentially the 
vital factors in the success or failure of fixed bridgework of any type. 
Attachments. 
Since the advent and during the experimental and evolutionary stages 
of fixed bridgework, a myriad of methods of obtaining attachment to the 
natural teeth have been suggested and used, but only a few are recognized 
now as useful and reliable. 
All methods of attachment necessarily involve some destruction of the 
supporting natural teeth, and hence the application of any method is 
largely a choice of evils. 
In the selection of the particular method which seems best adapted 
to the case in hand, the essential features which should be considered, are 
as follows: 
First: Which method will require the least destruction or mutilation 
of the supporting natural tooth. 
Second: Which method will best aid in the maintenance of the health 
of the supporting teeth and their investing tissues. 
Third: Which method will insure the greatest efficiency in the restora- 
tion of function. 
Fourth: Which method will insure the greatest permanency in the 
restoration. 
Fifth: Which method will be the least objectionable from the view- 
point of esthetics. 
These considerations constitute the basic requirements for attachments 
for fixed bridgework and should govern the selection made for each and 
every case. 
No two cases are alike in all of their details, and hence no one method 
is applicable universally. And when the selection of the method which 
seems best adapted to the case in hand has been made, then all of the re- 
quirements of adaptation must be met with the same care with which 
the selection itself was made. 
The methods of attachment now in general use, and which afford the 
maximum range of application, may be classified as follows: 
First: Full crown restorations. 
Second: Partial crown restorations. 
Third: Inlays. FIXED BRIDGEWORK 
293 
Full Crown Restorations. 
As attachments for fixed bridgework, full crown restorations of any 
type unquestionably comprise the most permanent method of procedure. 
While some simpler method often may offer assurance of several years 
of usefulness, and postpone final restoration by means of a full crown, 
thus adding to the aggregate longevity of the supporting tooth, still, the 
use of a full crown is indicated in many cases as the best means of ob- 
taining a maximum of strength and of permanency in the initial restoration. 
Dowel Crowns. 
The use of dowel crowns as attachments for fixed bridgework is indi- 
cated whenever it may be warrantable to sacrifice all of the remaining 
natural crown to the gingival line, or whenever it may have been sacri- 
ficed to this point previously, and especially when any of the ten anterior 
teeth is involved. 
Any of the various types of dowel crowns having a gold, or platinum 
coping may be used, and each crown should be made and finished as a single 
unit before the final grouping and assembling of the pontics. And when 
two or more dowel crowns are to be used in one fixture, parallelism of the 
dowels must be secured and provided for in the enlargement of the canals 
to receive them. 
In the use of dowel crowns as attachments for bridgework, each 
and every crown must be made and finished as a single unit, first, irre- 
spective of the size or relationship of the pontics to be supported by it. 
This is important and is necessary because the porcelain tooth or facing 
used must be placed directly over its supporting root in order to comply 
with the combined requirements of esthetics and sanitation. 
Frequently, in cases where the supporting abutment root has moved or 
shifted mesially or distally, there is a temptation to place the porcelain 
tooth or facing to the mesial, or to the distal of the coping adapted to its 
supporting root, in order to make accommodation for the pontics to be 
supplied. But, unless the porcelain tooth or facing is placed immediately 
over its supporting root and in a direct line with its long axis, a shoulder 
is made by the offset, and whenever a shoulder is formed in this manner, 
it is formed at the expense of sanitation. 
Use of All-Porcelain Teeth. In the use of all-porcelain teeth in the 
construction of dowel crowns which are to be used as attachments for 
bridgework, it is essential that the coping should present a surface of 
metal mesially, or distally, which will be adequate to the requirements of 
strength in the assemblage of the crown to the fixture. 294 
CROWN AND BRIDGEWORK 
This provision obtains in the use of the Goslee tooth, and with any 
of the all-porcelain crowns having detachable dowels, by grinding the 
mesial, or distal surfaces in such manner as to accommodate an extension 
of the coping which will afford opportunity for soldering in the final 
assemblage. 
This mesial and distal extension of the coping must present toward 
the edentulous space on one or both sides in all cases, and must be suffi- 
ciently heavy to facilitate soldering and to insure strength in the final 
assemblage. 
Fig. 265. 
Fig. 266. 
The requirements of construction of the coping in this connection and 
the typical application of the Goslee tooth is illustrated in Fig. 265. 
When any other type of all-porcelain tooth is used, it may be ground 
in similar manner and to similar form, or it may be ground upon one 
surface only, as the requirements of soldering may demand, and as illus- 
trated in Fig. 266. 
Use of Porcelain Facings. In the use of dowel crowns with por- 
celain facings, the ideal type of construction, of course, embraces the 
use of replaceable facings, but whether replaceable facings are used or 
not, each crown should be made and finished to the point of polishing as 
a single unit. If replaceable facings are used, however, the facings never 
should be cemented to place until after the final assemblage of the 
entire fixture. 
Telescope Crowns 
Full telescope crowns with or without a shoulder probably afford the 
most permanent means of restoration and attachment as applied to the 
molar teeth. Their use is more or less generally indicated whenever it is FIXED BRIDGEWORK 
295 
warrantable to prepare the supporting natural tooth to the extent de- 
manded for this type of crown. And when used as an attachment for 
bridgework, each crown should be made and finished as a single unit before 
the final grouping and assemblage of the fixture. 
Partial Crown Attachments. 
Notwithstanding the fact that full crown restorations probably ofifer 
opportunities for obtaining the maximum of permanency in the attach- 
ment of fixed bridgework, still, methods which require less destruction 
and mutilation of the supporting natural teeth, and which do not impinge 
upon nor involve the gingival tissues, present many advantages, and are 
indicated frequently. 
The advantages to be obtained from the use of partial crown restora- 
tions are, primarily and manifestly, those of natural tooth conservation; 
and any method which will conserve the supporting natural tooth crown 
and pulp vitality, and at the same time insure permanency in the attach- 
ment, has a wide field of usefulness and should be used whenever the in- 
dications are favorable. 
All methods of obtaining attachment to the crowns of remaining na- 
tural teeth may be grouped together and classified as partial crown attach- 
ments. These embrace many useful methods, but none susceptible to uni- 
versal application. Therefore the selection of the one best adapted to the 
case at hand must be made with discriminating judgment, and with the 
conservation of the natural tooth crown and of pulp vitality as the domi- 
nating factor. 
Partial Shoulder Crowns 
The partial shoulder crown, commonly called the “three-quarter” 
crown, is indicated and used only as an attachment for fixed bridgework. 
As applied to the six anterior teeth, it is the most difficult and yet the 
most ideal method of attachment now in use, and is indicated whenever 
teeth favorable to the requirements of the preparation present; whenever 
the required preparation can be attained, and whenever the adaptation 
may be made with accuracy and certainty. 
The partial shoulder crown will appeal to all who are skilled craftsmen, 
but its application requires skill of a high order, combined with careful 
and precise technic, first, in the preparation of the supporting natural 
crown; second, in the construction of the attachment as a single unit; 
third, in transferring the work to the laboratory; and in the final as- 
semblage of the fixture of which it is to become a part. 296 
CROWN AND BRIDGEWORK 
Fig. 267. FIXED BRIDGEWORK 
297 
When a partial shoulder crown is used as an attachment, it may be 
made either by the direct or by the indirect method, as indicated previously, 
and it should always be made of a high fusing special alloy. 
Also, parallelism with all other attachments must be obtained, and ex- 
treme care must be exercised in taking the final impression, in making the 
final cast, and in the assemblage of all parts with solder. It must be noted 
especially that the attachment is seated properly and securely in the impres- 
sion, that it is sustained in position firmly on the cast, and that no change 
in its relationship may occur as a result of the shrinkage of solder in the 
final assemblage. 
When all of these precautions have been taken, the partial shoulder 
crown has a wide field of usefulness as an attachment for fixed bridgework, 
but otherwise some simpler method is indicated. A series of partial shoul- 
der crown attachments is illustrated in Fig. 267. 
Groove Attachments 
A much simpler form of attachment may be designated as a simple 
groove attachment, though it is known both as the Carmichael and the 
Alexander attachment, and has been used more or less successfully for 
many years. 
Anterior Teeth. In the application of this method of attachment 
to anterior teeth, a simple groove is cut into the center of the mesial and 
distal surfaces of the supporting natural crown, and the two lateral grooves 
then joined by cutting a groove through the lingual plate of enamel, as 
illustrated in Fig. 68. 
Previous to cutting the grooves, the mesial and distal walls must be 
made to assume straight and parallel lines which is done with a thin vulco- 
carborundum disk. The mesial and distal grooves then should be cut, 
using small cylindrical stones first and finishing with a cross-cut fissure bur. 
The lingual groove then is made, using first a thin vulco-carborundum 
stone and finishing with a round bur. 
The grooves are cut to a depth which would accommodate a round 
wire, about 17 or 18 gage. Pure gold, about 36 gage, then is adapted 
to these grooves, and to cover the entire lingual surface of the natural 
tooth crown. 
This adaptation may be made by burnishing directly to the tooth, or by 
the indirect method. When the adaptation has been completed, the pure 
gold should be trimmed to the outlines desired, and then reinforced prop- 
erly. The reinforcement may be made either by casting or by soldering. 
Casting. If the casting method is used, the form and contour de- 298 
CROWN AND BRIDGEWORK 
sired should be made by building on the pure gold with casting wax; the 
sprue-former is then attached and the piece invested and cast, using a 
good clasp-metal alloy. 
While this type of attachment might be made by the indirect method 
entirely, and without the use of pure gold as a matrix, still, the use of 
pure gold in the manner indicated, insures a better surface adaptation and 
diminishes the possibilities of any change of form which might be caused 
by shrinkage. 
Fig. 268. 
Fig. 269. 
Soldering. If the reinforcement of the pure gold is to be made by 
soldering, it should be protected with base-plate wax and then removed 
carefully and invested properly for soldering. Clasp-metal wire, 17 or 18 
gage, should be fitted into the groove carefully, bending one piece of wire 
to fill the groove completely. The reinforcement may be made with a high- 
grade solder. Small pieces of clasp-metal plate may be placed here and 
there to impart additional strength and resilience to the finished attach- 
ment. (Fig. 268.) When the attachment has been completed by either 
method it should be finished to the point of polishing and then adapted 
finally to its supporting tooth. 
On account of the more favorable shape of the crowns of the cuspid 
teeth, this method of attachment is more generally useful when applied 
to these particular teeth, but it is applicable also to bicuspids. FIXED BRIDGEWORK 
299 
Posterior Teeth. In the application of a simple groove attachment 
to bicuspid teeth, the lingual cusp must be sacrificed to accommodate a 
restoration of sufficient occlusal thickness to insure strength; and the 
mesial, distal and lingual surfaces must be reduced to an extent which will 
admit of a close adaptation at the gingival line. The grooves then should be 
cut as illustrated in Fig. 69, and the attachment made in the manner de- 
scribed. Because of the difficulty of burnishing even 36 gage pure 
Fig. 270. 
gold directly to the tooth, the best results are secured by the use of the in- 
direct method. A good unit impression, and a good amalgam cast will 
insure a good adaptation, but the use of a matrix of pure gold, previously 
adapted to the amalgam cast by burnishing, is necessary and advantageous 
for the reasons mentioned. The completed attachment is illustrated in 
Fig. 269. 
Pin Attachments. 
A simple pin attachment involving only the lingual surface of the sup- 
porting tooth is used frequently in obtaining attachment to the six anterior 
teeth, only. 
Vital Pulps. In the application of this simple method of attach- 
ment to the upper anterior teeth having vital pulps, the lingual surface of 
the natural tooth crown is first ground sufficiently to admit of the presence 
of a protecting plate of gold. Two holes, having a diameter proportion- 
ate with the size of the tooth, and as deep as possible without endangering 
pulp vitality, are drilled into the body of the natural crown, and toward 
the mesial and distal angles, as illustrated in Fig. 270 A and B. 
In central incisors and cuspids, iridio-platinum, or clasp-metal wire, 18 
to 20 gage, should be used for pins and the holes should be drilled with 300 
CROWN AND BRIDGEWORK 
a spear drill or round bur of the same diameter. In lateral incisors, a 
smaller wire, of course, must be used. 
When the holes have been drilled and the pins fitted, pure gold, about 
36 gage, should be adapted closely to the entire lingual surface of the 
natural tooth crown by burnishing. When the adaptation has been com- 
Fig. 271. 
pleted, the pure gold should be perforated over the holes, and the pins ad- 
justed to place through the perforations, allowing a surplus of about two 
millimeters to project. 
The relationship of pins and pure gold (Fig. 270 C) now should be sus- 
tained with adhesive wax and the piece then removed, invested, soldered 
and reinforced heavily, using 22 or 20 karat solder. The pure gold is used 
as a support and protection to the pins, and to the mounting medium after 
mounting, and for the purpose of affording a soldering surface adequate 
to the requirements in the final assemblage of the fixture. Therefore, it 
should be as heavy as occlusion will permit, in order that it may not change 
form under the influence of stress. 
The surplus ends of the pins never should be cut off until the final as- 
semblage of the fixture has been completed for the reason that they facili- 
tate the removal of the attachment with the impression, and insure the cor- 
rect relationship of the attachment in the impression. 
In the application of this attachment to lower incisors, where it is par- FIXED BRIDGEWORK 
301 
ticularly useful, the holes necessarily must be smaller, and should be placed 
well toward the incisal end in order to minimize the danger of pulp in- 
volvement. In these teeth the pins should be made of 20 to 22 gage wire, 
usually. A typical application of this type of attachment to the lower in- 
cisors is illustrated in Fig. 271. 
Open-Face Crowns. 
The type of partial crown known as an open-face crown has been 
used as an attachment for fixed bridgework for many years, with vary- 
ing degrees of success and failure. 
Fig. 272. 
A minimum of destruction of the supporting natural crown, and sim- 
plicity of construction, which are always desirable features, constitute the 
chief advantages obtainable from the application of this type of attach- 
ment. These advantages cause it to have a limited field of usefulness. 
Anterior Teeth. Open-face crowns are applicable to the anterior 
teeth mainly, and to the cuspid teeth in particular. Because of the normal 
shape of the crowns of the cuspid teeth, less preparation is required in ob- 
taining adaptation than is required for any other type of attachment. The 
natural shape of the crowns of the lower incisors also is more or less fa- 
vorable for this type of attachment, but the more exaggerated bell shape 
of the crowns of the upper incisors demands such extensive preparation 
upon their mesial and distal surfaces as to contraindicate the use of an 
open-face crown in practically all cases. 
And even when the application is made to the crowns of teeth which are 
of favorable shape, and where but little destruction or mutilation is re- 
quired, this method of attachment does not subscribe to the esthetic re- 
quirements, and is objectionable for this reason. 
However, when this objectionable feature may be waived, or may be 
the lesser evil, and when a maximum conservation of the natural tooth 
crown is desired, the use of an open-face crown affords opportunity for 
a secure and more or less permanent attachment for fixed bridgework. 302 
CROWN AND BRIDGEWORK 
And as an attachment it will be successful and permanent in proportion as 
it may be well adapted and offer no degree of gingival irritation. This 
latter feature is a most important consideration at all times. 
The requirements of preparation have been illustrated previously in 
Figs. 70 and 71, and the requirements of construction in Fig. 120. 
Posterior Teeth. Simple open-face crowns also are applicable to 
the posterior teeth, and their use may be indicated upon these teeth in occa- 
Fig. 273. 
sional instances. In their application to bicuspids and molars, the lingual 
cusps should he sacrificed as indicated previously for groove attachments, 
and the mesial, distal and lingual surfaces of the natural tooth crown 
must be reduced to an extent which will admit of an adaptation at the gin- 
gival line. 
In many instances, however, an adequate attachment may be obtained 
without permitting the peripheral band to approach closely to the gingival 
tissues. Whenever this feature is obtainable with opportunity for sanita- 
tion and with reasonable assurance of integrity in the attachment to the 
supporting tooth, a free exposure of the tooth at the gingival line is a 
desirable feature. (Fig. 272.) 
Partial Telescope Crowns. 
Partial telescope crowns which do not involve contact with the gingival 
tissues are useful as attachments in many cases, and particularly where 
the supporting natural crown is of considerable length occluso-gingivally. 
In such cases, attachments of this type may be made to include and 
involve only the occlusal two-thirds of the crown of the supporting natural 
tooth, thus avoiding any impingement upon or contact with the gingival 
tissues. FIXED BRIDGEWORK 
303 
Whenever adequate strength in the attachment to the supporting abut- 
ment is insured, this type of partial crown possess a distinct advantage 
over a full telescope crown, and is a useful attachment for fixed bridge- 
work. 
Partial crowns of this type may be made with a band and a swaged 
or cast occlusal surface, or by the indirect method and casting, as de- 
scribed previously in connection with full telescope crown restorations. 
In the use of this type of attachment, the mesio-gingival, or disto-gingival 
edge of the telescoping band must be carried to a point where it will be 
free from contact with the adjacent natural tooth crown, or the pontic, 
or both, as illustrated in Fig. 273. 
Inlays. 
Inlays of some form may afford attachment for all types of fixed 
bridgework. With the advent of the cast inlay it was thought that the 
possibilities of adaptation insured a successful means of attachment to 
the remaining crowns of supporting natural teeth in all classes of cases, 
and for all types of bridgework, and simple inlays were used indiscrimi- 
nately, but with disastrous results in many instances. 
With the increasing demands of prophylaxis, any effort to conserve 
natural tooth structure and to make restorations, or to obtain attachment 
for bridgework without impinging upon the gingival tissues, or otherwise 
disturbing the normal conditions, is highly commendable. Inlays sub- 
scribe to the requirements in these desirable features, but when used as 
attachments for bridgework, they must subscribe also to other require- 
ments if success is to be insured. 
A simple inlay, irrespective of how well it may fit the supporting cavity 
walls and margins, and of how well it may restore the supporting tooth 
as a single unit restoration, is not always a reliable attachment in bridge- 
work. But when all requirements are observed, inlays of some form 
have a wide range of application and a broad field of usefulness. 
In the use of inlays as attachments for bridgework, it must be recog- 
nized that the inlay must be adapted to the supporting tooth in „ such 
manner as to resist the influence of stress in all directions, and the influ- 
ence of torsion, in particular. Primarily, resistance to stress demands: 
First, that the supporting cavity be prepared properly; second, that the 
inlay be seated firmly in the cavity; and, third, that it be locked mechan- 
ically in its relation to the supporting tooth. 
The requirements of cavity preparation are based upon extension for 
prevention in all cases, and demand an observation of the following general 
rules: 304 
CROWN AND BRIDGEWORK 
First: The cavity should be formed with a square, flat base. 
Second: No weak and unsupported walls should present. 
Third: The axial margins should be slightly diverging and beveled 
sufficiently to protect the enamel rods. 
Fourth: All deep pits and fissures should be included in the cavity 
formation. 
Fig. 274. 
Fig. 275 
Fifth: All axial margins must be extended beyond any possible con- 
tact with adjacent natural teeth or pontics. 
Sixth: The linguo-axial margin presenting toward the edentulous 
space must be extended sufficiently to afford a free exposure of the inlay 
in order to facilitate soldering and to insure strength. 
Anterior Teeth.. In the use of inlays as attachments to the anterior 
teeth, but two general forms of cavity preparation are adopted generally. 
One involves the lingual and both mesial and distal surfaces of the sup- 
porting tooth, and is practically the same as described in connection with 
partial crown restorations. (Fig. 274.) The other involves the lingual 
and mesial or distal surfaces only, as illustrated in Fig. 275. 
Where the lingual and both mesial and distal surfaces are involved, 
the use of pins is not necessary, but where the lingual and mesial or distal 
surfaces only is involved, the use of one or two pins is usually necessary. 
In making inlays of the former type where no pins are used, either the 
direct or the indirect method may be used successfully. FIXED BRIDGEWORK 
305 
Posterior Teeth. In the use of inlays as attachments to the posterior 
teeth, the conditions vary to such an extent that it is almost impossible 
to follow any one typical outline, provided that the general rules govern- 
ing cavity formation are observed. A series of typical cavity formations 
and inlays are illustrated in Fig. 276. In simple inlays either the direct or 
the indirect method may be used successfully. 
Fig. 276. 
Use of Pins. Whenever there is any doubt as to the possibility of 
a secure attachment of an inlay to its supporting natural tooth crown, 
where it is to serve as an attachment for bridgework, often one, or more, 
pins must be used as a supplementary means of insuring stability and 
positive fixation. 
Teeth with Vital Pulps. In teeth having vital pulps, one, two, and 
sometimes three small pins may be used to good advantage, and are 
frequently necessary. 
In drilling holes for the reception of pins, it is important to place the 
holes at points which will insure stability, and yet will not endanger 
pulp vitality. A spear drill, or round bur, of the same size as the wire 
of which the pins are made should be used, and it is important that the 
holes should be drilled along parallel lines. 306 
CROWN AND BRIDGEWORK 
Pins which are to become an integral part of the inlay should be made 
of round iridio-platinum, or clasp-metal wire, 20 to 22 gage, and, in the 
use of pins, the best results are obtained by the use of a matrix made of 
pure gold, about 36 gage, and adapted previously by burnishing or swag- 
ing, which may be done either by the direct or the indirect method. 
Use of Matrix. The use of a matrix insures the proper relationship 
of the pins to the holes and with each other. When the cavity formation 
has been completed, the holes drilled, the pins fitted, and the matrix 
adapted satisfactorily, the matrix should be perforated over each hole. 
Each pin then should be forced through the perforation and to the full 
depth of the hole, allowing a surplus of about two millimeters to project. 
The relationship between matrix and pins now should be sustained 
with adhesive wax, then removed, invested, and each pin soldered to the 
matrix with a very small bit of high grade solder. Matrix and pins now 
should be replaced in position on the supporting tooth and finally trimmed 
and burnished. The desired restoration of contour then may be made 
by casting, or with solder, in the manner described previously. 
Without Matrix. In cases where only one, or perhaps two pins are 
to be used, a matrix may not be necessary. In such cases the surplus ends 
of the pins should be bent at right angles and the wax pattern then made 
directly in the cavity with the pins in position, and the casting made 
subsequently. 
Where no matrix is used, and where the wax pattern is adapted by 
the direct method, it is important to observe that the pins are engaged in, 
or attached securely to the wax pattern before the investment and casting 
are made. 
A typical preparation for bicuspid teeth in which only one pin is used 
in this manner, and for molar teeth in which two pins are used is illus- 
trated in Fig. 67. 
Separable Pins, In posterior teeth having vital pulps where the use 
of a pi* may be desirable, and yet where some danger of pulp complica- 
tions present, inlays having a separable pin which may be placed at any 
angle are sometimes useful. 
Separable single pins which may be inserted through the inlay and 
at a tangent with each other when two are used in the same fixture, and 
which may be placed at the time of the final mounting of the fixture, 
may be made by drilling the hole into the tooth at the desired point, first, 
to the required depth, and at any angle which will insure adequate strength 
with freedom from pulp complications. 
A pin of proper size and length then should be fitted into the hole FIXED BRIDGEWORK 
307 
allowing a liberal surplus to project. The wax pattern then should be 
made over and around the projecting end of the pin and when formed 
and contoured to the desired outlines, it should be teased gently until it 
may be removed from the cavity. The pin then should be warmed slightly 
Fig. 277. 
Fig. 278. 
Fig. 279. 
Fig. 280. 
Fig. 281. 
by grasping the surplus end with warm pliers, detached from the wax pat- 
tern, and a carbon point of the same diameter as the pin, then introduced 
into the opening. Inlay and carbon point now should be replaced in the 
cavity and the carbon point sealed to the wax pattern. (Fig. 277.) 
When removed, both ends of the carbon point should be exposed freely, as 
illustrated in Fig. 278. The pattern then should be invested and cast, 
after which the carbon may be removed by boiling in dilute hydrochloric 
acid. The inlays then should be finished (Fig. 279) and the fixture built 
independent of the pins. 308 
CROWN AND BRIDGEWORK 
Fig. 282. FIXED BRIDGEWORK 
309 
When completed, the fixture and pins should be mounted at the same 
time. The completed fixture, with the separable pins in place before 
mounting, is illustrated in Fig. 280, and the result after mounting and 
after removing the surplus ends of the pins, is illustrated in Fig. 281. 
Inlay in Combination with Partial Peripheral Band. 
One of the simplest and most useful methods of attachment to pos- 
terior teeth involves an inlay in combination with a partial peripheral 
band, made all in one piece by the indirect method and the casting process, 
as suggested by Dr. R. E. MacBoyle. 
As a means of circumventing the use of pins in inlay attachments, 
and of obtaining a maximum of strength in the fixation of the attachment 
to its supporting tooth with a minimum of tooth destruction, and as a 
means of avoiding any impingement upon, or contact with the gingival 
tissues, and of affording every opportunity for soldering the attachment 
to the fixture, this type of attachment is useful. 
Because of involving and including a partial peripheral band adapted 
to the largest circumference of the supporting natural tooth crown, the 
use of pins is unnecessary, less extensive cavity preparation is required 
and the indirect method is used exclusively, as described previously. 
The requirements of preparation consist, first, in reducing the con- 
vexity of the mesial or distal axial wall adjacent to the edentulous space, 
and then forming a cavity of typically retentive outlines. The peripheral 
band must involve only the largest circumference of the axial walls em- 
braced, and usually need not embrace more than half of the circumference 
of the supporting natural tooth crown. 
A series of typical attachments of this type are illustrated in Fig. 282. 
Pin Inlay Attachments. 
A combination of pin and inlay attachments both for anterior and 
posterior teeth, which embrace a distinctive and more or less ideal type 
of preparation, has been suggested and is used extensively and success- 
fully by Dr. James Kendall Burgess. 
Anterior Attachments. The preparation required for attachments 
to the anterior teeth consists in making three or four steps in the lingual 
surface of the natural tooth crown, and making each step of dimensions 
large enough to form a seat with a flat base and square shoulder, and 
large enough to accommodate a hole for the reception of a pin, as illus- 
trated in Fig. 283. 310 
CROWN AND BRIDGEWORK 
Posterior Attachments. The preparation required for attachments 
to the posterior teeth consists first in reducing the convexity of the mesial 
or distal axial wall adjacent to the edentulous space, and then forming a 
cavity not deeply, but of typical retentive outlines. Holes then are drilled 
for the reception of pins. 
A matrix is made of 36 gage, pure gold, in the adaptation of which 
either the direct, or the indirect, method may be used. When the matrix 
Fig. 283. 
Fig. 284. 
is adapted properly and trimmed to the desired outlines, perforations are 
made over each hole, and the pins are carried to place through the perfora- 
tions. The relationship is sustained with adhesive wax, and the matrix 
and pins are removed, invested, and the pins attached to the matrix with 
solder. The pin inlay then may be completed by investing and building 
the contour with 22 karat solder, or by casting. The typical preparation, 
together with completed attachments, are illustrated in Fig. 284. 
This type of attachment is useful also for stabilizing loose teeth. 
Stabilizing Loose Teeth. 
Attention has been directed previously to the advantages obtainable 
by stabilizing loose teeth. In many cases this procedure is indicated 
and offers possibilities for adding to the comfort, usefulness and reten- 
tion of teeth for many years. Stabilizing loosened teeth will not remove 
a pathological condition, but where no lesion exists, or where existing 
lesions may be cleared up, fixation puts the teeth to rest and gives Nature 
a chance to build up and restore. 
The stabilizing of loosened teeth may be accomplished by two methods 
of procedure: First, by simple bands made and adapted first as single 
units and then assembled into one continuous fixture and cemented to 
place; and, second, by a series of pin-locked inlays made also as single 
units, and then assembled into one fixture and mounted. 
When simple bands are used, they should be made narrow upon the FIXED BRIDGEWORK 
311 
labial surface, and wide upon the lingual surface, in order to avoid any 
unnecessary or objectionable display of metal. Iridio-platinum, or 22 
karat gold plate, 32 gage, is used for this purpose. The bands should 
be made first and fitted carefully to each tooth to be involved in the fixa- 
tion, then placed in position on the teeth and an impression in plaster 
obtained. 
Fig. 286. 
Fig. 285. 
After removing the impression, it should be noted that each band 
is in its proper position, after which the impression should be varnished 
and filled with soldering investment compound which crystallizes. Press- 
ing the point of an ordinary pin firmly into the center of the imprint of 
each tooth and band in the impression before pouring the cast will insure 
strength in the cast. The bands then should be assembled, using only a 
sufficient quantity of solder to insure strength, and when assembled prop- 
erly, the fixture should be finished, polished and mounted. 
The use of pin-locked inlays requires the drilling of two small holes 
in the lingual surface of each tooth to be included in the final fixation. 
These holes should be of the size of 19 or 20 gage round wire, and, in 
anterior teeth, should be placed well toward the incisal end, and well 
toward the mesial and distal angles, both of anterior and posterior teeth, 
in order to avoid pulp complications. 
While drilling the holes and otherwise preparing the natural teeth, 
they may be stabilized temporarily by previously molding impression com- 
pound to their labial and buccal surfaces, and tying it to place with 
ligatures as illustrated in Fig. 285. 
When the holes are drilled, each inlay should be made separately, using 
a matrix of pure gold, 36 gage. The matrix may be made either by the 
direct or the indirect method. 312 
CROWN AND BRIDGEWORK 
When each inlay has been made as a single unit, all should be placed 
in position on the teeth and an impression taken in plaster. The same 
precautions indicated previously for simple bands should be taken in 
obtaining the cast. The inlays then should be assembled into one fixture 
with a high-grade solder, and subsequently finished and polished. 
The finished result, showing large interproximal spaces, and the absence 
of any cause for gingival irritation, is illustrated in Fig. 286. 
Fig. 287. 
Pulpless Teeth. 
In the use of inlays as attachments for bridgework, in pulpless teeth, 
one strong dowel of a size proportionate with the size of the tooth in- 
volved, will meet the requirements in all teeth having but one root canal. 
In multi-rooted teeth two dowels may be used if necessary, but care should 
be taken not to weaken the supporting natural crown unnecessarily. 
Even in multi-rooted teeth one dowel will be sufficient usually, and 
this should be placed always in the largest canal. When one dowel only 
is used, a matrix rarely ever is indicated, and the best results are obtained 
by making the inlay by the direct method and casting to the dowel. As 
a means of insuring accuracy, the surplus end of the dowel should be 
retained in all flat-surface inlays until after the final assemblage of the 
fixture. 
Temporary Attachments. 
Fixed bridgework may be indicated at times in cases where any prep- 
aration of the crowns of the supporting natural teeth either is inadvisable 
or impossible. 
Cases of this character often present in the mouths of young patients, FIXED BRIDGEWORK 
313 
where the replacement of missing teeth is essential to the correction of 
malocclusion, and where any immediate or appreciable destruction of the 
crowns of natural teeth is inadvisable; and in cases of advanced age, 
frequently, any preparation of the natural crowns of teeth might be inad- 
visable or unnecessary because of the physical condition of the patient. 
In such cases, some simple form of attachment might be indicated in 
preference to any procedure which would involve some destruction and 
mutilation of the crowns of natural teeth. 
Fig. 288. 
Simple bands made of 22 karat gold plate, or of platinum, 32 gage, 
made in the usual manner and fitted closely to the largest circumference 
of the natural tooth crown, without any preparation whatever, often will 
serve a useful purpose in these cases. 
In obtaining attachment to the anterior teeth, the band should be as 
narrow as possible upon the labial surface, but wide enough upon the 
lingual surface to insure stability and to prevent displacement, as illustrated 
in Fig. 287. 
Attachments to the posterior teeth should be adapted in similar man- 
ner, but should be provided with an occlusal extension, resting into the 
mesial and distal embrasures, as a means of precluding displacement. 
(Fig. 288.) 
Lingual Supports. 
In the construction of small anterior fixtures, where one tooth is sus- 
pended anterior to its abutment, some provision against the rotation of 
the abutment tooth on its long axis, and the resulting displacement of the 
suspended pontic, always must be provided. What is called a “lingual 
support” is used for this purpose. 
A lingual support may or may not be sanitary, and may or may not do 314 
CROWN AND BRIDGEWORK 
injury to the natural tooth crown against which it rests. Both depend 
entirely upon its adaptation. 
In the use of lingual supports the following basic features must be 
observed: 
First: The support must be sufficiently strong to withstand the stress 
imposed upon it. 
Second: It must be in direct contact with the adjacent natural crown 
at its extreme end only. 
Fig. 289. 
Fig. 290. 
Third: It must not impinge upon the gingival tissue. 
Fourth: It must not interfere with the opposing teeth. 
If these requirements are met carefully, lingual supports may be sani- 
tary, and will do no serious injury to the natural crown against which 
they are placed. 
Round iridio-platinum, or clasp-metal wire, about 16 or 17 gage 
should be used, and the adjustment can be made best after the case has 
been invested, and just previous to heating and soldering. The require- 
ments of adaptation are illustrated in Fig. 289. 
Occlusal Rests. 
In the replacement of one, or sometimes two, posterior teeth, the canti- 
lever type of fixture which involves positive fixation at one end, and a 
simple rest into a filling at the other end, is used frequently, and has 
some advantages. The advantages obtaining consist mainly in permitting 
each abutment tooth to move more or less independently of the other in 
functioning. 
A simple projection, extending from the fixed part of the structure 
and resting into an inlay restoration, in or near the occlusal surface of 
the adjacent abutment tooth, provides a flexible or movable joint at this FIXED BRIDGEWORK 
315 
end of the fixture, and yet offers adequate support against both vertical 
and lateral stress. These projections are known as “occlusal rests.” 
In the construction of inlay restorations which provide for an occlusal 
rest, the inlay should be made and finished as a single unit first. A seat 
having a flat, square base, with slightly flaring axial walls, then should be 
cut into the center of the occlusal surface extending toward the gingival 
margin as illustrated in Fig. 290. The dimensions of this seat should 
be such as to accommodate freely, round or square iridio-platinum, or 
clasp-metal wire, about 16 gage. When the seat has been prepared in 
Fig. 291. 
this manner a matrix of pure gold, about 36 gage, should be burnished 
well into the seat, allowing a slight surplus to overlap upon all margins. 
A piece of wire as indicated should be cut of proper length and fitted into 
the pure gold matrix. The relationship should be sustained with adhesive 
wax, and matrix and wire then invested and united with 22 or 20 karat 
solder, using sufficient solder to make all surfaces smooth and continuous. 
When soldered and finished a well adapted occlusal rest obtains. A 
surplus projection of the wire always should present as a means of insur- 
ing proper relationship and adequate strength in the final attachment of 
the occlusal rest to the fixture. 
Occlusal rests, made in this manner, should be finished and polished 
finally, after the fixture is mounted, and will fit so closely as to be more 
or less sanitary. A typical application has been illustrated previously 
in Fig. 254. 
Another method of providing an occlusal rest is to drill a simple, 
round hole of suitable dimensions in the wax inlay pattern just previous 
to investing and casting and at a point not involving any of the margins. 
This may be done with a spear drill or round bur. When the inlay has 
been cast and finished the hole should be reamed out smooth and the end 
of a piece of iridio-platinum, or clasp-metal, wire fitted into it carefully. 
The surplus end of the wire then should be bent to close contact with the 
axial wall of the inlay so as to offer opportunity for attachment to the 316 
CROWN AND BRIDGEWORK 
fixture and without interfering with the correct placement of the adjacent 
pontic. When the fixture is completed and finally polished, fixture and 
inlay restoration are placed in their correct relationship and mounted at 
the same time. (Fig. 291.) 
Pontics. 
“Pontic” is the name given to an artificial tooth used as a substitute 
for a missing natural tooth in the construction of dental bridgework. 
To the patient pontics play a most important role. And, if missing 
natural teeth could be replaced successfully without abutments and with- 
out attachments, esthetics often would be the chief, if not the only 
requirement demanded. 
But, in the art of replacing missing teeth in all except edentulous cases, 
to the dental craftsman the abutments are the foundation, the attachments 
are the keystone, and the pontics are the superstructure only. 
And, yet, even though the pontics are third in the order of construc- 
tion, they, too, must subscribe to all requirements of usefulness, sanitation 
and permanency, as well as to the requirements of esthetics in particular. 
The basic requirements of pontics, therefore, are manifold: First, 
they must restore function; second, they must be of such form and shape 
as to insure sanitation; and, third, they must meet all demands of esthetics. 
Hence, the selection of the type of pontic which will be or which is best 
adapted to all requirements of the case in hand is an important considera- 
tion in the construction and application of dental bridgework, and no one 
type is applicable universally. 
Selection of Type. Previous to the selection of the type of pontic 
best adapted to the requirements, each attachment should be finished to 
the point of polishing, as a single and separate unit. The finished attach- 
ments then should be placed in position upon their supporting teeth and 
an accurate bite and an accurate impression secured. 
Bite. The bite should be taken in base-plate wax previous to taking 
the impression, and care must be observed to obtain the normal occluding 
relationship of the opposing natural teeth. 
When taking the bite it is absolutely essential to observe that the 
jaws are closed in centric occlusion. This procedure is not easily con- 
trolled because there is always a pronounced tendency to move the 
mandible forward or laterally, or to close into some position of eccentric 
occlusion when biting through wax, or when resistance is offered. 
Impression. When the bite has been taken as indicated, it should be 
observed again that all attachments still remain in their proper relationship FIXED BRIDGEWORK 
317 
with the supporting abutments and the impression then should be taken 
in plaster. Except in very small cases, the final impression should include 
all remaining natural teeth in the arch. After removing the impression, 
all attachments should be seated firmly in their correct position therein 
and the impression then varnished. 
Fig. 292. 
Any attachments which are to be detached from the cast during the 
construction of the fixture, should be painted with melted wax previous 
to pouring the cast. This precaution will facilitate their detachment, but 
should be taken only when detachment is necessary. 
Attachments never should be detached from the final cast, however, 
unless absolutely necessary, and when they are not to be detached it must 
be observed that they are filled completely in pouring the cast. 318 
CROWN AND BRIDGEWORK 
Cast. The cast should he made of a high-grade soldering invest- 
ment compound whicji crystallizes, is of a dense, smooth texture, and 
which does not shrink nor expand appreciably during or after 
crystallization. 
When the cast has been obtained, the bite should be adjusted care- 
fully, and the case then mounted upon an articulator as illustrated in 
Fig. 292. 
The selection and the correct adjustment of pontics can be made 
properly only after the case has been mounted upon the articulator. And, 
Fig. 293 
except in very small cases, the use of some form of anatomical articulator 
is advantageous. 
Anterior Pontics. 
In the replacement of missing anterior teeth three different types of 
pontics are used. These embrace: First, replaceable porcelain facings; 
second, replaceable all-porcelain teeth; and, third, flat-back facings with 
platinum, or platinum alloy pins. 
Median Line. In the selection of anterior pontics involving the re- 
placement of central incisors, the median line must be preserved at all 
times and under all conditions. Any deviation from the median line 
will destroy completely all esthetic possibilities. (Fig. 293.) Therefore, 
it must be established definitely and positively. 
Width. With the median line as a guide, the pontics must be of 
such width as will be required to fill the edentulous space with the proper 
number of pontics. And they must be of proportionate and uniform size 
and the same on each lateral side of the arch. FIXED BRIDGEWORK 
319 
The width of the pontics, therefore, is governed entirely by the num- 
ber of pontics required to fill the edentulous space on each lateral side of 
the arch, from the median line to each lateral abutment, and, irrespective 
of the distribution of the abutments, each lateral side must correspond. 
Uniformity and symmetry must obtain always if a high order of 
esthetics is to be achieved. 
Length. In order to conform to the requirements of esthetics, when- 
ever possible, the pontics should be of the same length as the crowns of 
any remaining natural anterior teeth. Also, they should be of a length 
which will permit the gingival edge to rest firmly upon the mucosa, and 
the incisal ends to correspond with the length of the crowns of the re- 
maining natural teeth. 
In the replacement of all six anterior teeth, where there is no other 
guide, the lip line and the requirements of occlusion will govern the length, 
and the normal arc of the circle should be restored always. 
Color. The highest possibilities in esthetics demand always that the 
color of the remaining natural teeth be simulated closely. Whenever 
a more or less perfect match in color is impossible, a shade darker, rather 
than one lighter, should be selected, and when several teeth are used in 
the same case, some slight variation in color often is advantageous. 
In the use of porcelain facings of any type, the translucency of the 
porcelain is destroyed by the presence of metal backings. Hence, the 
facings are always a shade darker after being attached permanently by 
cementation, or by soldering, and an allowance for this change must be 
made at the time of making the selection. 
Replaceable Facings. 
Replaceable porcelain facings are the most generally applicable and, 
therefore, the most useful type of pontic for the replacement of missing 
anterior teeth. Several different designs have been suggested and manu- 
factured, but the type known as Steele’s Interchangeable Facings of the 
“Trubite” mold are used, practically to the exclusion of all others. 
Special backings are made in gold alloy and in a base-metal alloy for 
each size of facing. While either will withstand casting, or will withstand 
a high-grade solder, still, those made of gold alloy are more reliable and 
should be used always. 
The backings should be obtained at the time the facings are selected, 
and the selection of duplicate facings at the same time also is always 
advisable. 320 
CROWN AND BRIDGEWORK 
When the selection has been made, each facing should be ground first 
to the desired and required adaptation to the cast, and with each other. 
The backings for each facing then should be fitted. The gingival and 
mesial and distal edges of the hackings should he finished flush and smooth 
with the facings, but a slight surplus should he allowed to remain at the 
incisal edge, as illustrated previously in Fig. 159 C. This affords oppor- 
tunity for a better protection of the porcelain facing after cementation. 
Whenever the requirements of occlusion will admit of reinforcement, 
some reinforcement of the incisal ends of each hacking as a single unit 
should be made. This may be accomplished by attaching a piece of 
Fig. 294 A, 
clasp-metal, or 22 karat plate, 28 or 30 gage, with solder, previous to 
the final assemblage. (Fig. 159 E.) The completed pontic showing the 
protection of the incisal end is illustrated in Fig. 294 A. 
And where several backings are to be assembled in one fixture, they 
should he assembled previously, in sections of two or three. By this 
means the final assemblage of facings and backings upon the cast previous 
to investing and soldering is facilitated; and because of the advantage 
obtainable from the use of a minimum of solder fused at one time, in 
the final assemblage, the precaution also facilitates the final soldering. 
Relationship of Gingival Edge of Facing to Mucosa. Where the 
natural teeth have been missing for any considerable length of time, and 
where more or less complete alveolar absorption has occurred, the cast 
should be relieved immediately beneath the gingival edge of each facing, 
after it has been ground to fit, in order to insure a firm bearing of the 
neck of the facing upon the mucosa, as illustrated in Fig. 294 B. If this 
precaution is not taken, this end of the facing will not rest firmly against 
the mucosa in the finished fixture. 
Recent Extraction. In cases where the restoration is made immedi- 
ately following the extraction of the roots of the natural teeth, which is a FIXED BRIDGEWORK 
321 
desirable procedure always, and a necessary one frequently, instead of 
overlapping the gingival edge of the pontic upon the mucosa, it should be 
inserted into the socket left open by the extraction of the root. 
The depth to which the gingival end of the pontic may be extended, 
or may project into the socket of recently extracted teeth, varies some- 
what in each case, but a projection equal to from one-fourth to one-third 
of the length of the root, and never exceeding one-third, is safe, generally, 
and if no irritation presents, the sockets usually close in over and around 
such projections, and the tissues become hard and dense and remain 
healthy. 
When it is desirable to so place the pontics that their gingival ends 
project into the sockets left by recently extracted roots, the sockets should 
Fir. 294 B. 
Fig. 294 C. 
be packed with aseptic gauze soon after extraction and kept open in this 
manner until the completion and final mounting of the fixture. 
As a means of affording an accurate cast, and of facilitating the proper 
placement of the projecting gingival ends of facings into the sockets, just 
previous to taking the bite and the impression, each socket should be 
filled with a plug of base-plate wax, made plastic and molded carefully 
in such manner as to fill the socket and to project slightly. If the surplus 
projection is shaped favorably, these plugs will be removed with and be- 
come part of the impression, and, later, of the resulting cast. When 
the cast has been obtained, the plugs may be removed with boiling water. 
The necks of the facings then may be placed into the sockets thus formed 
in the cast with a degree of certainty and accuracy. Pontics so placed 
afford a more permanent relationship with the mucosa, and provide a 
correlation which in no way interferes with the normal process of 
absorption. 
Pontics with Porcelain Root Extensions. Pontics having porcelain 
root extensions, which project into the sockets left by teeth recently ex- 
tracted, or which are formed in the edentulous tissues for their accommo- 
dation by surgical procedure, are used in some cases, and recommended 322 
CROWN AND BRIDGEWORK 
as an ideal method of procedure. Steele’s replaceable facings, or Flat- 
back facings, may be used, and a special technic is required for each. 
The completed pontic is illustrated in Fig. 294 C, and the special technic 
used is described in the construction of posterior politics. 
In the replacement of any single one, or perhaps two, of the six 
anterior maxillary teeth, when the pontic may be inserted immediately 
following the extraction of the root, or roots, extensive absorption may 
be prevented, or delayed appreciably, and normal contour may be pre- 
served thus, for a time, but the advantages are doubtful, both in character 
and in degree of permanency. 
Fig. 295 A. 
Fig. 295 B. 
While it is recognized that the mucosa takes kindly to the presence 
of and contact with highly-vitrified porcelain, still no attachment of course 
ever occurs, and, therefore, in the absence of attachment, a pocket must 
be present; and in proportion as tbe area of unattached tissues increases, 
the area of the pocket increases; and in proportion as the area of the pocket 
thus formed increases, the possibilities of hygiene and sanitation decrease. 
And, hence, politics with porcelain root extensions must be regarded 
as ideal but unsanitary restorations. 
Final Assemblage on Cast. 
Before the final assemblage of facings and backings upon the cast it 
should be observed that each facing may be detached from its backing 
easily. When this precaution has been taken, facings and backings should 
be assembled in proper position on the cast and the relationship of each 
backing sustained securely with adhesive wax. FIXED BRIDGEWORK 
323 
When the desired relationship has been sustained, the facings then 
should be detached carefully and backings and attachments then invested 
properly and assembled finally with solder. 
All-Porcelain Replaceable Teeth. 
Wherever the extent of absorption and the requirements of occlusion 
are favorable, the Goslee tooth or any of the all-porcelain crowns with 
detachable dowels, ground to similar basal formation, may be used 
successfully. (Fig. 295 A.) 
Restoration of natural tooth form, color and translucency, with a 
minimum display of metal are the advantages obtainable from the use 
of all-porcelain replaceable teeth as pontics; but unless the extent of 
absorption affords an abundance of space, these advantageous features 
obtain at the expense of opportunities for sanitation. Hence, this type 
of pontic is not applicable universally. 
In the use of this type of pontic the selection should be made with 
great care and a size of tooth which will require but little or no grinding 
should be used always. Any extensive grinding beyond that demanded 
by the requirements of retention to the basic structure, by backing and 
soldering, is done at the expense of the strength of the porcelain, and 
weakened porcelain of any form, or shape, only invites failure. 
Whenever it is impossible to obtain the exact size in width and length, 
then the preference should be given to a size smaller, rather than to one 
larger, in order that grinding to the point of weakening the porcelain 
may be avoided, and it is well always to select duplicates of each tooth at 
the same time. 
When the selection has been made in accordance with the require- 
ments, a backing of 36 gage pure gold should be made for each pontic 
by burnishing, or swaging. A retaining dowel then should be fitted and 
soldered to the backing, using 22 karat solder. After soldering the re- 
taining dowel, the backing should be placed in position again on the pontic 
and finally burnished and trimmed to the desired adaptation and outline. 
Each backing then should be reinforced to the full extent of the de- 
mands of strength and contour, as a single unit, which may be done with 
22 karat solder by investing again, or by casting. (Fig. 295 B.) 
Flatback Facings with Pins. 
Flatback porcelain facings having pins made of platinum, or of plati- 
num alloy, baked in them, antedated replaceable facings and this type of 324 
CROWN AND BRIDGEWORK 
facing was used formerly and exclusively in the construction of pontics 
for all types of dental bridgework. 
In view of the many advantages obtainable from the use of inter- 
changeable, or replaceable, porcelain teeth and facings, however, and in 
view of the objectionable features presenting and always resulting from 
the use of facings which are retained in their relation to the basic struc- 
ture by means of soldering, the field of usefulness of this type of facing 
in the construction of anterior pontics now is limited. Indeed, there is 
no longer any excuse for the use of pin facings which are soldered to the 
basic structure, except in porcelain work. 
Fig. 296. 
When used in connection with gold fixtures, the selection should be 
made in accordance with all requirements indicated previously for re- 
placeable facings and with the same care. Each facing then should be 
ground to meet all requirements of adaptation and when so ground should 
be backed properly. 
Since the porcelain facing, which is to be soldered, must be amply 
protected against stress, the backing must be of uniform thickness, and 
of adequate strength to insure the protection necessary. 
In order that this protection may obtain, the incisal end of the facing 
should be ground first until a sharp angle presents, as illustrated pre- 
viously in Fig. 160. Pure gold, about 36 gage, then should be perforated 
to engage the pins properly, and adapted closely to the facing by burnish- 
ing. The backing now should be trimmed to a close, flush joint upon 
the gingival, mesial and distal surfaces, but allowing a surplus to extend 
upon the incisal end. 
When so adapted, the backing then must be reinforced. Uniform and 
adequate reinforcement of the backing is secured in the best manner by 
adapting a supplementary backing made of 22 karat, 28 or 29 gage gold 
plate, extending from and including the pins and to the incisal end only. 
When both backings are adapted properly, they should then be united 
with a small bit of high-grade solder as illustrated previously in Fig. 162. 
When each facing has been backed in the manner indicated (Fig. 296), 
all facings should be assembled in place upon the cast, and the relationship FIXED BRIDGEWORK 
325 
sustained with adhesive wax, after which they may be invested and 
soldered. A simple technic for making flat-back facings replaceable is 
described in connection with posterior pontics. 
Posterior Pontics. 
In the replacement of missing posterior teeth four general types of 
pontics are used. These embrace : First, all porcelain replaceable teeth; 
second, replaceable facings with occlusal surface restorations made in 
gold; third, flatback pin facings with occlusal surface restorations made 
in gold; and, fourth, solid cast pontics; and many variations in the methods 
of procedure in the use of these basic types are followed. 
All-Porcelain Replaceable Teeth. 
Whenever the extent of absorption and the demands of occlusion are 
favorable to the requirements of strength and sanitation, an all-porcelain 
replaceable tooth is the ideal type of posterior pontic. 
The conspicuous display of occlusal surface restorations of gold in 
fixed bridgework construction is and always has been an objectionable 
feature. The use of all-porcelain replaceable teeth overcomes this and 
subscribes to the highest possibilities, both in esthetics and in efficiency. 
Advantages., The reproduction of natural tooth form in pontics is 
desirable always and should obtain whenever possible, but it must not 
obtain at the expense of sanitation. And efficiency, too, is a requirement 
which must be observed always, but efficiency must not be temporary. 
It must be permanent. 
For actual masticatory purposes, an occlusal surface of porcelain 
if the glaze is removed insures greater efficiency than an occlusal surface 
of gold, but porcelain is destructible and gold is indestructible, and these 
are vital factors in the selection of pontics. 
Indications. In the use of all-porcelain pontics, efficiency and perma- 
nency may be combined, but they can be combined only when the porcelain 
may be of proportions sufficient to insure strength, primarily, and when it 
then may be adequately supported and protected against stress by the metal 
superstructure. 
Whenever all-porcelain replaceable teeth may be used as posterior 
pontics under these conditions, then the use of this type of pontic is indi- 
cated. But where insufficient space presents, and where the requirements 
of occlusion are exacting, greater indestructibility than is possessed by all- 
porcelain replaceable pontics may be demanded. And when indestructi- 326 
CROWN AND BRIDGEWORK 
bility is demanded, and is the first requirement, the use of all-porcelain 
replaceable teeth as posterior pontics is contraindicated. 
This type of pontic also is contraindicated in all cases which do not 
present every opportunity for sanitation. Opportunity favorable to sani- 
tation demands a more or less extensive absorption of the edentulous 
tissues in order that the lingual surface of the completed pontic may be 
of such shape and' form, and may be placed in such relationship with 
the mucosa as to make sanitation possible. An extent of absorption, a 
Fig. 297, 
relationship, and a shape and form of lingual surface which would make 
sanitation difficult and practically impossible, and which, therefore, would 
contraindicate the use of all-porcelain teeth as posterior pontics is illus- 
trated in Fig. 297. 
When the indications for the use of posterior pontics of this type are 
favorable, three types of replaceable porcelain teeth may be used. These 
embrace the ordinary Diatoric vulcanite teeth, the Goslee tooth, and 
Steele’s interchangeable bicuspids and molars. 
Diatoric Teeth. Diatoric bicuspid and molar teeth, designed for 
vulcanite work, are also well adapted to use as pontics for fixed bridge- 
work. 
In the use of Diatoric teeth, the selection as to type, size and color 
must be made with care, and with a view to avoiding all or any unneces- 
sary grinding. For the reason that the form is favorable, and that grind- 
ing to any appreciable extent only weakens the finished politic, this precau- 
tion should be taken always. 
Backing. When the selection has been made, each tooth should be 
adapted properly to all of the requirements of the case, primarily, and 
then each tooth should be backed with pure gold about 36 gage. The 
backing may be adapted by burnishing, or by imbedding the tooth in 
impression compound and swaging. The backing should be so adapted as FIXED BRIDGEWORK 
327 
to box in the porcelain tooth completely upon all surfaces except the 
buccal and occlusal. 
Reinforcing. When the backing has been adapted and trimmed as 
indicated, it then should be perforated over the hole in the porcelain and 
burnished to close contact into and with the walls of the hole. Each 
backing then should be reinforced heavily and uniformly and contoured 
to the desired form and shape as a separate unit. The reinforcement and 
contouring necessary may be done either by casting or with solder. 
Fig. 298. 
Casting. When it is desirable to make the reinforcement and con- 
touring by casting, the interior of the hole should be lubricated with oil, 
and casting wax then shotild be pressed firmly into it first, after which 
all of the reinforcement and contour desired should be made also with 
casting wax. The sprue-former then should be inserted into the wax at 
its thickest point, and the investment and casting made. 
The use of a backing adapted previously, as indicated, is absolutely 
necessary as a means of overcoming shrinkage and warpage and of thus 
insuring accuracy of adaptation when the casting process is used, and the 
casting should be made with a good grade of casting alloy. 
When the casting has been made, if a physical union between the 
pure gold backing and the alloy used in casting does not obtain, a small 
bit of high-grade solder should be used, taking care that it does not flow 
over upon the pure gold. The use of whiting or of any anti-flux will 
prevent such a mishap. 
Each porcelain tooth then should be fitted carefully into its respective 
backing, and each backing finished to the point of polishing as a single 
unit. (Fig. 298.) 
Before the final assemblage of the pontics upon the cast, previous to 
investing and soldering, it should be observed that each tooth may be 
detached easily from its backing. This precaution insures ready detach- 
ment of each porcelain tooth previous to investing, and the use of stick 
adhesive wax will facilitate this procedure. 
With Solder. Each pontic must be backed with pure gold, pri- 
marily, as indicated, and each backing must be reinforced uniformly and 328 
CROWN AND BRIDGEWORK 
adequately, and contoured to meet the requirements, as indicated. These 
features are imperative and may be accomplished best by casting. But, 
with care, they may be accomplished with solder, though not with the 
same degree of certainty and accuracy. 
When the reinforcement of each backing as a single unit is to be made 
with solder, a sustaining dowel of a size proportionate with the size of 
the hole in the pontic and with the demands of strength must be used. 
Fig. 299. 
Round iridio-platinum, or high-fusing clasp-metal wire, 12 to 16 gage, is 
used for this purpose. 
When the pontic has been backed properly, the backing should be 
perforated slightly immediately over the center of the hole and a short, 
blunt, sustaining dowel then forced through the perforation to the full 
depth of the hole, allowing a surplus to project. The relationship between 
backing and dowel now should be sustained with adhesive wax, allowing 
the wax to cover this surface of the backing fully and completely. This 
precaution will insure a clean surface, freely exposed, when backing and 
dowel have been removed from the pontic and invested. 
Backing and dowel should be invested carefully in soldering investment 
compound, allowing the wax to remain freely exposed. When the in- 
vestment compound has crystallized, the wax should be removed with 
boiling water, the exposed surfaces of backing and dowel fluxed properly, 
and the investment then heated. 
The relationship between backing and dowel then may be sustained 
and the necessary reinforcement and contour made with solder. Since 
subsequent soldering in the final assemblage will be necessary, 22 karat 
solder should be used at this time. When the desired and required rein- FIXED BRIDGEWORK 
329 
forcement and contour obtain, each backing should be finished and the 
assemblage upon the cast, and the final investment made, as has been 
described. 
The Goslee Tooth. 
The Goslee tooth was designed for universal use in the restoration 
of the crowns of teeth as single units, and as a pontic for bridgework. 
Fig. 300 A. 
Fig. 300 B. 
In the construction of posterior pontics this, or a similar type of all- 
porcelain replaceable tooth, is useful. The lingual and retentive surface is 
convex, both mesio-distally and occluso-gingivally. This admits of a 
maximum of porcelain and a shape favorable to the requirements of sani- 
tation, and definite angle margins for the adaptation of the backing are 
provided. (Fig. 299.) 
The use of this type of tooth for posterior pontics is indicated in the 
same class of cases as permit the use of Diatoric teeth. It offers the 
same advantageous features, and is used in exactly the same manner, 
and with exactly the same technic as described for the Diatoric tooth. 
Round iridio-platinum, or clasp-metal wire, 14 gage, should be used for 
the sustaining dowel, and each tooth should be back with 36 gage pure 
gold (Fig. 300 A), and the backing reinforced subsequently, either by 330 
CROWN AND BRIDGEWORK 
casting or with solder, and finished as a single unit as indicated. Rein- 
forced backings, made by casting, are illustrated in Fig. 300 B. Fixtures 
showing the application of both anterior and posterior politics of this type 
are illustrated in Fig. 301. 
Fig. 301 
Fig. 302. 
Backings Made in Sections of Two or Three. Backings including 
two and even three teeth may he made in a single unit by backing each 
tooth first with pure gold, separately, assembling the backings primarily 
by forming the reinforcement and contour with casting wax, and then 
casting; or, by investing and making the reinforcement and contour with 
high-grade solder. 
This procedure may be indicated in cases of extensive absorption of 
the edentulous space, but better results will be obtained, usually, by making 
each backing as a separate unit. FIXED BRIDGEWORK 
331 
Backings made in sections by casting are illustrated in Fig. 302. 
In the use of politics of this type, the selection should be made with 
painstaking care, and duplicates should be provided and the definite 
formula of mold and color used should be recorded in all cases. 
Fig. 303 A. 
Fig. 303 B 
Steele’s Posteriors. 
Steele’s interchangeable “posteriors” also are a useful type of pontic. 
(Fig. 303 A.) In the illustration, “A” shows the post hole, “B” shows the 
rib-slot, and “C” shows the plane surface. On account of the thinness 
of the occlusal surface of porcelain, this type of pontic, perhaps, is more 
generally applicable than either of the preceding types, but the shape of 
the lingual surface of the completed pontic often is not favorable to the 
highest requirements of sanitation. 
Special backings, made both in gold alloy and in base metal alloy 
are provided in two sizes. (Fig. 303 B.) The post “A” and “C,” and the 
rib “B” and “D” vary in size. Gold alloy backings, however, always 
should be used. Backings which do not extend to the gingival edge of the 
tooth, and which do not form a complete box for the porcelain, however, 332 
CROWN AND BRIDGEWORK 
present an element of weakness. (Fig. 304 A.) Such extensions may 
and should be made by attaching a small piece of pure gold, 36 gage 
(Fig. 304 B), to each backing with solder (Fig. 304 C), and after solder- 
ing (Fig. 304 D), burnishing the extension to include and overlap the 
gingival edge. (Fig. 304 E.) When thus backed (Fig. 304 F), adequate 
Fig. 304. 
reenforcement and desired contour may be made either by casting, or 
with solder, and this should be done and each pontic finished as a separate 
unit before the final assemblage. 
Use of Tube Teeth. 
An all-porcelain pontic to be used in combination with gold, and 
requiring the presence of an individual saddle resting upon the mucosa 
beneath each pontic, is known as the tooth. It is made like 
Ash and Sons’ “tube” tooth, with a round central hole extending entirely 
through the occlusal surface. A round wire of the same diameter as the 
hole is attached to the saddle in a vertical line and supports the tooth, 
which is cemented to place after the completion of the fixture. Porcelain 
rods are made for the purpose of filling the occlusal surface of the hole 
afterward. 
Because of the objectionable features incident to the use of a saddle 
in fixed bridgework, this type of pontic is applicable more particularly FIXED BRIDGEWORK 
333 
to removable structures, though it may be used successfully in fixed struc- 
tures which are built in gold. The esthetic results, however, are obtained 
at the expense of sanitation. The use of this type of pontic is described 
in the chapter on Removable Bridgework. 
Replaceable Facings. 
Next to the use of all-porcelain teeth, replaceable facings used in 
combination with an occlusal surface restoration made in gold, as a part 
of the backing, is the most useful type of posterior pontic. 
Fig. 305. 
This type of pontic is indicated in all cases where the esthetic require- 
ments demand the use of porcelain, and yet where the stresses of occlusion 
demand greater indestructibility than is afforded by the use of an all- 
porcelain tooth. 
Steele’s replaceable facings may be used successfully in the construc- 
tion of posterior pontics of this type. In their use, the selection as to 
size and color should be made with the same care as indicated previously, 
and backings and duplicates should be obtained at the same time. 
Each facing then should be ground to the requirements of adaptation 
and the backings fitted and trimmed as already described. (Fig. 305 A.) 
Suitable occlusal surface restoration then may be made as a part of the 
backing, either by casting or swaging, and each pontic should be made 
as a single unit primarily. 
Casting. When the occlusal surface restoration is to be made by 
casting, which is the best and simplest procedure, each respective facing 
and backing should be placed in position on the cast and the requirements 
of contour and occlusion met by molding casting wax to the backing, 
and then forming and carving the wax to the desired outlines of the 
occlusal restoration. (Fig. 305 B.) 
It should be observed that the backings are clean and free from oxida- 
tion, and that the casting wax is attached securely, and all of the require- 334 
CROWN AND BRIDGEWORK 
ments of occlusion, and of typical tooth form, should be obtained by 
carving. 
When these requirements have been observed, the facing should be 
detached carefully, the sprue-former attached securely at a favorable point 
in the wax, and backing and wax invested carefully and the casting made. 
Gold alloy backings should be used always. A good grade of casting 
alloy, fused and cast properly, will attach securely to the backing, pro- 
vided that the mold is not overheated before casting. 
Fig. 306 A. 
Fig. 306 B. 
In investing, it must be observed that the exposed surface of the back- 
ing is covered entirely and thus protected with the investment compound, 
and in order to prevent unnecessary disintegration, the mold should he 
burned out and heated carefully, and never overheated before casting. 
When the casting has been made it should be cleaned in the acid bath, 
the facing fitted, and the pontic then finished to the point of polishing, as 
a single unit. When each pontic has been completed in this manner, it 
should be observed that the facing may be detached easily. The pontics 
then should be assembled on the cast, the relationship sustained securely 
with adhesive wax, the facings then removed and the case invested, and 
the final assemblage with solder made. 
Swaging. When the occlusal surface restoration is to be made by 
swaging, any of the die, or die-plate methods of forming the occlusal 
surface may be used successfully, and 22 karat gold plate, 28 to 30 gage, 
should be used. 
When suitable dies have been selected, and the swaging completed, 
the buccal surface of tbe occlusal restoration should be trimmed away as 
indicated in Fig. 306 A, and then fitted carefully and closely to the desired 
relationship with the facing and backing. This relationship then should 
be sustained with adhesive wax (Fig. 306 B), and the facing detached. FIXED BRIDGEWORK 
335 
Backing and occlusal restoration now should be invested, and soldered, in 
which procedure all of the desired contour of the lingual surface should 
he made. While the desired contour may be formed with solder alone, 
it may be facilitated greatly by the use of small spheroids of 22 karat gold 
plate, previously prepared. These are not fused with the solder, and, 
hence, any desired contour is obtainable with ease, and when finished 
withstands the final assemblage without change of form. 
Fig. 307. 
When the soldering and contouring have been completed, the same pro- 
cedure indicated for casting then should be followed carefully. 
Swaging in Sections of Two or Three. Two, or even three, pontics 
may be made in this manner at one time by carving special occlusal sur- 
face restorations, making special dies in fusible alloy, and swaging all in 
one piece, as illustrated in Fig. 307. No advantage obtains from this 
procedure, however, and proper and individual lingual contour is made 
more difficult. 
Flatback Pin Facings. 
Flatback porcelain facings, having pins baked in them, combined with 
gold occlusal surface restorations, and all united with solder, were the 
primitive type of posterior pontics, and politics made in this manner 
are still used. 
The use of pin facings which are attached to the superstructure by 
soldering, however, must be regarded generally as an antiquated method 
of procedure and as a method offering no possible advantages, but some 
objectionable features. 
The objectionable features incident to the use of pin facings soldered 
to the superstructure have been considered elsewhere, but may be enu- 
merated again as follows: 
First: The presence of pins baked into the porcelain weakens the 
facing to begin with; second, the influence of heat and of expansion and 
contraction in soldering further endangers their strength; and, third, 336 
CROWN AND BRIDGEWORK 
opportunity for replacement and repair with any degree of facility does 
not present. 
In view of these objectionable features, and of the advantages obtain- 
able from the use of replaceable facings, the use of pin facings which are 
soldered to the basic structure does not afford a type of posterior pontic 
which subscribes to the maximum of requirements. 
Fig. 308 A. 
Fig. 308 B 
In the primitive method of using pin facings in the construction of 
posterior pontics, the occlusal surface restoration was made by swaging. 
It then was filled to its full depth with solder. The occlusal end of the 
facing then was ground flat and at a right angle with the buccal surface. 
The facing then was backed with thin, pure gold, and facing and occlusal 
surface restoration invested and attached with solder. The finished pontic 
presented an entire occlusal surface of gold. This extensive display of 
gold is unnecessary and objectionable and is overcome now by trimming 
away the buccal surface of the occlusal restoration, and so fitting the 
facing to it as to avoid any unnecessary display of gold and to present 
but a minimum line upon the buccal surface of the completed pontic. 
The comparative esthetic results are illustrated in single pontics in Fig. 
308 A, and in completed structures in Fig. 308 B. FIXED BRIDGEWORK 
337 
Soldering. In the construction of posterior pontics of this type, the 
facings should be selected as indicated, but duplicates are unnecessary 
if they are to be attached by soldering. When the selection has been 
made, each facing should be ground to meet the requirements of adapta- 
tion. They should be backed then with pure gold, about 36 gage, leaving 
a slight surplus project beyond the occlusal angle. (Fig. 309 A.) The 
Fig. 309 A. 
Fig. 309 B. 
Fig. 309 D. 
Fig. 309 C. 
backing should be retained then in its relation to the facing by bending 
the pins over upon it, as illustrated previously. 
The occlusal surface restoration then is made by swaging, and when 
swaged and trimmed to the outlines desired, the buccal surface should 
be cut away to the occlusal angle. (Fig. 309 B.) Facing and backing 
now should be fitted to each other in such manner as to present only a 
thickness of gold at the occlusal angle which will be adequate to protect 
the porcelain. When fitted in this manner the relationship should be 
sustained with adhesive wax, and then invested as indicated in Fig. 309 C. 
The final assemblage and the contour required then is made with solder, 
as described previously. (Fig. 309 D.) 
Casting. In the use of pin facings in the construction of posterior 
pontics, the occlusal restoration may be made also by the casting process. 
In the use of the casting process, however, it is not necessary, nor is it 
desirable, to cast directly to the porcelain facing. And, if this is not done, 
the advantages of a replaceable, or a cemented facing mav be obtained. 
In making the. occlusal restoration by casting, and to obtain the 
advantages of a cemented facing, the facing should be ground and backed 338 
CROWN AND BRIDGEWORK 
as indicated, except that the pins should not be bent over upon the back- 
ing, but should be made straight and parallel. 
With the backing in position on the facing, the pins should be lubri- 
cated with oil, and a piece of casting wax of suitable proportions heated 
in water and then molded over the projecting pins and against the backing. 
The casting wax then should be sealed to the backing securely around all 
Fig. 310. 
edges, using a heated spatula. It then should be contoured and carved 
until the desired outlines obtain. 
The facing now should be teased loose and detached carefully from 
backing and wax, and, when removed, carbon points of the same diameter 
of the pins are introduced through the holes in the backing, and to the 
full depth in the wax. 
The investment and casting then should be made, after which the 
carbon points may be removed by boiling in dilute hydrochloric acid. The 
holes formed by the carbon points should be reamed out with a spear 
drill, or round bur, of similar diameter, and the facing fitted to place. 
The assemblage on the cast should follow, the facing should be removed 
and the final investment and final assemblage with solder made. 
Flat-back Facings Made Replaceable. A simpler and much better 
method of making a flat-back facing replaceable comprises the use of 
what are known commercially as “Lockit Cups.” (Fig. 310 A.) In FIXED BRIDGEWORK 
339 
the use of these simple agencies it should be observed that the pins are 
straight and parallel. They should then be threaded, and a cup placed 
over each. The threading of the pins is recommended for the purpose 
of facilitating cementation. (Fig. 310 B.) A backing of 36 gage 
pure gold should now be adapted to facing and cups, the relationship 
sustained with wax, the facing then removed, and backing and cups in- 
vested and attached with a small bit of solder. (Fig. 310 C.) 
The occlusal surface restoration may then be made and the pontic 
completed by casting, or by swaging and soldering, as described pre- 
Fig. 311 
viously. (Fig. 310 D.) This simple technic makes a useful pontic, 
affords all of the advantages of a replaceable facing, and constitutes the 
only way in which a flat-back facing should be used. 
Gingival Extensions of Porcelain. 
If the highest requirements in the direction of health conservation, 
and of sanitation could be met in all cases, and at all times, the ideal pontic 
would be one made entirely of porcelain. But the requirements of stress 
and strength, and the inherent weakness of porcelain demand greater 
indestructibility. The advantages obtained from placing a surface of 
highly vitrified porcelain in contact with the mucosa, however, may be 
achieved by combining gold and porcelain, and making posterior pontics 
having gingival extensions of porcelain, as suggested by Dr. E. T. Tinker. 
(Fig- 311-) 
Pontics of this type, unquestionably, are the nearest approach to the 
ideal, and the most sanitary type of construction, but they are not ap- 
plicable universally. The field of usefulness is limited to those cases 
where the extent of absorption permits the use of pontics of consider- 340 
CROWN AND BR1DGEWORK 
able occluso-gingival length, and in such cases pontics of this type afford 
the highest type of construction. 
A knowledge of porcelain work, and an exactness of technic are de- 
manded in the construction, and either Steele’s replaceable facings, or 
posteriors, or flat-back facings may be used. 
In the use of Steele’s replaceable facings, or posteriors, special “angle 
backings” and “root-sections” are provided for this work, and a special 
Fig. 312 A, 
Fig. 312 B 
technic is required. (Fig. 312 A.) Flat-back facings also may be used 
in the manner illustrated in sequence in Fig. 312 B. 
The facings should be selected, ground, and the gingival extension 
made in porcelain, and of such proportions as will admit of resting gently 
upon the mucosa, leaving large, free, open interproximal spaces between 
the politics themselves, and between the pontics and the attachments. 
When the gingival extension is so formed, and adapted properly by 
final grinding, it is then re-fused and carried to a point which presents a 
highly vitreous surface. The pontic then should be backed with pure gold, 
36 gage, and the contour and restoration desired made in casting wax. 
The facing should be removed, and the occlusal surface restoration made 
by casting. FIXED BRIDGEWORK 
341 
The use of “Lockit Cups” facilitates the procedure, and affords all 
of the advantages of a replaceable facing. 
Facings and occlusal surface restorations, finished as single units, are 
assembled, the facings removed, and the case invested and assembled 
finally, with solder, in the manner described previously. 
Fig. 313. 
Wherever the extent of absorption and the requirements of occlusion 
will permit the use of this more or less ideally sanitary type of pontic, a 
conservation of health, and increased opportunities for sanitation obtain. 
Solid Cast Pontics. 
In the replacement of missing posterior teeth, many cases present 
where the requirements of esthetics are not exacting, where opportunity 
for sanitation is of greater importance, or where the requirements of 
occlusion demand absolute indestructibility. In such cases the use of a 
solid cast pontic may be indicated, as the best means of obtaining a maxi- 
mum of combined requirements in the restoration of function. 
Solid cast pontics for posterior teeth may be made separately as single 
units, or to involve and include two, or even three teeth in one section. 
In the construction of this type of pontic, whether as a single unit, or 
including two or three teeth, the most ideal formation from the view- 
point of sanitation is obtainable from a triangular shape, with the apex 
of the triangle presenting toward, and approaching closely to, the mucosa. 
(Fig. 313.) 
If this general formation obtains, and if large interproximal spaces 
between the pontic and the attachment present, all surfaces are exposed 
freely, may be reached by the tooth-brush nicely, and may be kept clean 
easily. 
The so-called “self-cleansing” type of occlusal restoration which in- 
cludes the restoration of the occlusal surface only, types of which are 342 
CROWN AND BRIDGEWORK 
illustrated in Fig. 314, is a travesty on the possibilities of sanitation. 
Mouth hygiene and oral sanitation demand that all surfaces of dental 
bridgework which is attached in a fixed manner should be exposed and 
accessible as nearly as possible always; but this condition does not obtain 
beneath simple occlusal surface restorations, and hence, “self-cleansing” 
is a fallacy, and this type of construction is to be condemned. 
Fig. 314. 
In the construction of solid cast politics, casting wax made plastic in 
hot water should be molded to the cast, in such manner as to fill com- 
pletely the edentulous space between the attachments and to accommodate 
the requirements of occlusion. The cast should be varnished previous to 
molding the wax as a means of preventing its becoming attached thereto. 
When molded to meet all requirements, the wax should be detached 
and then carved to the shape and form desired and required. The sprue- 
former now should be attached securely and the investment and casting 
made. The casting should be made of a good grade of casting alloy 
similar in color to the alloy used in making the attachments. After the 
casting has been made, the pontic should be finished as a single unit and 
finally assembled, invested and soldered. 
Silicate Cement Facings. 
Aside from a failure to subscribe to the requirements of esthetics, 
the chief objection to solid cast politics made in the manner described lies 
in the more or less extravagant use of gold, and the weight of the finished 
fixture resulting therefrom. 
Esthetic features may be increased and the amount of metal other- 
wise required may be reduced to advantage often and without deviating 
from the desired shape and form of the completed pontic, by the use of 
silicate cement. Whenever these features and possible advantages may 
be desirable, suitable accommodation for the silicate facings should be 
provided in the wax pattern just previous to investing. FIXED BRIDGEWORK 
343 
This may be accomplished by removing the entire buccal surface of 
the wax pattern and forming a cavity of retentive shape and with definite 
margins, and as deep as may be practical, in the body of the pattern. The 
formation of the cavity in the wax pattern is made easily by the use of a 
large, round bur in the engine and a sharp carving instrument, or with 
the “suction carver” designed for similar purposes. When all unneces- 
sary thickness of wax is reduced, and when the requirements of reten- 
tion have been met, as illustrated in Fig. 315, the pattern then should be 
invested and cast. 
Fig. 315. 
When the casting has been made, the pontic should be finished and 
assembled as indicated previously. The silicate cement facing should 
not be placed until just before the fixture is to be mounted, and should 
be polished smoothly before mounting. Much artistic effort may be dis- 
played in the construction of posterior pontics in this manner, but the 
advantages obtained will depend upon the permanency of the silicate 
cement. If any doubt as to the permanency of these products prevails, 
the same advantageous features may be obtained by burnishing a matrix 
and making a baked porcelain inlay. 
Bucco-Lingual Dimensions of Posterior Pontics. 
While the restoration of function is one of the imperative requirements 
of posterior pontics, still the abutment teeth receive all of the stress 
assumed by the pontic. Therefore, in proportion as the stress imposed 
upon the pontics may be diminished without destroying their usefulness, 
the degree of stress which must be assumed by the abutments likewise 
will be diminished correspondingly. Hence, the dimensions of the occlusal 
surface restorations of all posterior pontics never should be greater than 
the actual requirements of usefulness demand. And, furthermore, in 
proportion as the bucco-lingual dimensions of posterior pontics are re- 
duced, the opportunities for sanitation are increased. 344 
CROWN AND BRIDGEWORK 
The mesio-distal dimensions cannot be reduced beyond the require- 
ments, but the bucco-lingual dimensions may be and should be confined to 
the requirements of restoration of function only, and should be held within 
these limitations at all times. 
Fig. 316. 
Articulation of Pontics. 
The articulation of the politics is important, and should be observed 
carefully, and with a full comprehension of the requirements of func- 
tional occlusion. 
If the pontics are improperly articulated one of two evils must 
result. Either they will be in a position of malocclusion with a propor- 
tionate reduction in masticatory efficiency, or they may be so incorrectly 
placed in relation to the occlusal planes as to induce traumatic occlusion, 
or result in fractured porcelain teeth or facings. 
Assembling, 
Since no structure which is designed to endure can be stronger than 
its weakest point, the final assemblage of all of the single units of which 
the fixture is composed is an important procedure in the construction of 
fixed bridgework. FIXED BRIDGEWORK 
345 
Requirements. The requirements of assembling, therefore, must be 
observed in detail and with great care. These requirements are as 
follows: 
First: When all of the single units have been completed and finished 
to the point of polishing, they should be assembled in proper position and 
relationship on the cast, and the position and relationship then sustained 
securely with adhesive wax. (Fig. 316.) 
Second: All surfaces of metal which are to be and which should 
be exposed in the investment, as a means of facilitating the final assemblage 
with solder, then should be covered with wax also. 
Fig. 317 A. 
Third: The cast now should be removed from the articulator and 
immersed in cold water until all confined air is dispelled. This will be 
indicated when air bubbles cease to rise. 
Fourth: A high grade of soldering investment compound, which 
crystallizes, should be mixed to the proper consistency, and then applied 
freely to and over all surfaces of metal, or of porcelain, which have not 
been covered by wax. 
Fifth: When the investment has crystallized the wax should be re- 
moved with boiling water. 
Sixth: When all wax and residue have been removed, all surplus 
overhanging edges of investment should be trimmed away until a free 
exposure of all surfaces which should be exposed obtains. 
Seventh: The entire investment then should be reduced by trimming 
away all unnecessary surplus and leaving the final investment of propor- 
tions no larger than necessary to insure strength, and to withstand heat. 
(Fig. 317 A.) 
Eighth: All particles of debris must be removed, and all surfaces 
of metal must be clean. 
Ninth : All parts to be assembled must be in apposition and if absolute 
contact does not obtain small pieces of wire or of plate should be fitted 
carefully into the joint. 
Tenth: All surfaces to which solder is to become attached then 346 
CROWN AND BRIDGEWORK 
should be fluxed properly with borax mixed into a thin paste, and the 
case then placed over a flame and allowed to remain until heated thor- 
oughly, before attempting to effect the final assemblage with solder. 
Anterior Fixtures. In the final assemblage of fixtures involving the 
six anterior teeth, it is necessary always to adopt some means of insuring 
adequate strength, while preserving the individuality of each facing, 
when facings are used, by preventing the complete union of the backings 
from the gingiva to the incisal end. 
Fig. 317 B. 
Nothing adds more to the esthetic features of anterior fixtures than 
the absence of any display of gold in the interstices, and, hence, it should 
be observed that the backings do not come in direct contact at the incisal 
ends. Filling in between the incisal ends of the backings with a thin 
solution of whiting before the case is heated, which may be done easily 
with a small, pointed brush, will prevent the solder from running into 
the joint and uniting the backings at the extreme incisal ends. 
As this procedure usually will leave but a very small portion of the 
backings in direct contact, extreme care must be exercised to obtain the 
necessary strength in the assemblage. Adequate strength may be insured, 
however, by fitting a piece of round iridio-platinum, or clasp-metal wire, 
about 18 gage, across the backings at about the center, and from cuspid 
to cuspid, before the case is heated, and then uniting the backings only 
over and around this wire. (Fig. 317 B.) 
If each backing has been reinforced previously, adequate strength, 
and a better lingual contour will result. In this connection it is always 
desirable to carry as small a quantity of solder to a fluid state at one 
time as possible, in order to minimize shrinkage, and the value of the 
use of wire in this manner, therefore, is apparent. 
Posterior Fixtures. No special precautions, other than those indi- 
cated, are demanded in the assemblage of posterior fixtures, but it must 
be observed that the requirements of strength and contour obtain always. FIXED BRIDGEWORK 
347 
Soldering. All of the precautions incident to soldering which have 
been emphasized previously must be taken, but by way of special emphasis, 
it should be remembered that no effort to solder ever should be made 
until the case has been allowed to remain on the burner sufficiently long 
to become heated thoroughly. 
If the surfaces of metal and solder then have been fluxed properly, 
but little effort will be required, and the ordinary combination blow-pipe 
will answer the purpose. While compressed air may be used in extensive 
Fig. 318. 
cases requiring large investments, still, to regulate and control the heat 
with the mouth blow-pipe is manifestly more reliable and safer. 
In the management of a large mass of solder, such as is required in 
assembling extensive fixtures, the procedure may be facilitated greatly by 
cutting the solder into good-sized pieces, and then using the sharpened 
point of an ordinary slate pencil to pull, push, or guide it to the desired 
point when in the state of fluidity, and, in placing the solder, long, pointed 
pliers may be used with more comfort, of course, than short ones. 
When considerable filling in, or contouring is required, previously 
melting gold plate, or scrap, into globules of various size, and then placing 
these properly before fusing the solder, also will facilitate and expedite 
the work of soldering. 
When the soldering has been completed, the heat should be discon- 
tinued, and the case allowed to cool slowly, before removing from the 
investment. When removed, it should be cleaned in boiling dilute hydro- 
chloric acid, then finished to the point of polishing, after which all re- 
placeable teeth, or facings, should be cemented, and the final polish given. 
Final Considerations. 
Throughout the construction and application of fixed bridgework suc- 
cessful achievement will depend, not so much upon the method used, nor 
upon the technic followed, as upon a knowledge and observation of correct 
basic principles. 348 
CROWN AND BRIDGEWORK 
In the building of fixed bridgework the basic principles which must 
be observed always, embrace and include, first, a correct relationship 
between the abutments and the attachments; second, a correct relationship 
between the attachments and the pontics; third, a correct relationship be- 
tween the pontics themselves; and fourth, a correct relationship between 
the pontics and the mucosa. 
This relationship is illustrated typically in Fig. 318. 
Fig. 319. 
Some idea of the highest esthetic possibilities in the replacement of 
missing teeth by means of fixed bridgework is illustrated, through the 
courtesy of F. P. Worth, in Fig. 319. 
Whatever may be the shortcomings of fixed bridgework, and however 
far it may be from a physiologically ideal method of procedure, when 
used only where indicated, and when built along the lines suggested, no 
indictment not supported by damaging clinical evidence is rational or 
tenable. 
And, if clinical evidence is of value, and, if the legend, “a survival of 
the fittest,” may be applied to the methods of replacing missing teeth and 
holds true, fixed bridgework will be doing good service when all other 
methods, except clasp and full dentures, will have been abandoned, or 
forgotten. FIXED BRIDGEWORK 
349 
Basic Rules. 
The following basic rules may be regarded as fundamental to the 
successful application of fixed bridgework: 
1. Primarily, all conditions must be favorable. 
2. Favorable conditions demand good health, and every opportunity 
for proper sanitation. 
3. While the most ideal physiological conditions present when only 
teeth of similar functional activity are involved, and when the 
abutment teeth may move slightly independent of each other, while 
functioning, yet neither is imperative. 
4. Sound basic mechanical principles must obtain in all cases. 
5. The teeth are capable of withstanding stress in excess of their 
own normal functional demands to a limited degree. 
6. One tooth will do the work of two teeth under favorable conditions. 
7. The distribution of the abutments must be favorable to the re- 
quirements of stress and strength in all cases. 
8. Usually the number of abutment teeth should be equivalent 
to the number of missing teeth to be replaced. 
9. When the number of pontics to be supplied exceeds the number 
of abutments, the strength of the abutments must be equal to 
the requirements of stress. 
10. A greater number of abutments than is required to meet the 
demands of stress and strength is not necessary and never should 
be used. 
11. Never more than one pontic should be suspended from the abut- 
ment, or abutments. 
12. When one pontic is suspended from one abutment, the pontic 
never should be larger than the abutment. 
13. When one pontic is suspended from one abutment, the abutment 
and not the pontic must assume the burden of stress. 
14. In designing and planning fixtures of any size it is necessary to 
recognize that the first molar is the center of masticatory stress, and 
that the degree of stress diminishes as it radiates from this com- 
mon center. 
15. A pontic may be suspended anterior, but never posterior, to the 
abutment, or abutments, except to prevent elongation of opposing, 
or migration of adjacent teeth. 
16. In suspending a single pontic from a single abutment in the region 
of the anterior teeth, a provision against rotation of the abutment, 
and lateral displacement of the pontic, must be made. 350 
CROWN AND BRIDGEWORK 
ly. In suspending a single pontic from a single abutment in the pos- 
terior teeth, the efficiency of the pontic will depend entirely upon 
adequate provision against vertical stress. 
18. A first bicuspid pontic never should present an occlusal surface 
of normal proportions. 
19. Whatever type of attachment is used, it must fit. 
20. Whatever type of pontic is used its shape must insure sanitation. 
21. Whenever porcelain teeth or facings are used they should be of 
the replaceable type. 
22. Large interproximal spaces between attachments and politics and 
between the pontics themselves must present always. 
23. In the assemblage of attachments and pontics, the soldered joint 
should involve the immediate contact points only, in anterior fix- 
tures, and the occlusal one-third only, in posterior fixtures. 
24. The structural formation of fixed bridge work possesses no greater 
strength than obtains at its weakest point. 
25. Strength adequate to the requirements of stress must obtain in 
every part of the fixture. 
26. The gingival edge of all anterior pontics should be rounded and 
smooth, and should rest firmly upon the subjacent mucosa. 
27. The gingival edge of all posterior pontics may touch but never 
should rest firmly upon the subjacent mucosa. 
28. The bucco-lingual dimensions of posterior pontics never should 
be greater than actual efficiency demands. 
29. No form of saddle of any size or shape resting upon the subjacent 
mucosa ever should be used in fixed bridgework. 
30. The greatest success in fixed bridgework will result in cases in 
which two, three, four, five, and possibly six, teeth are involved. 
31. Where more than six teeth, and where bilateral fixtures of the 
complex type are involved, successful application will depend en- 
tirely upon favorable conditions, correct mechanical principles, 
careful technic, and diligent sanitation. 
32. A careful mounting and a final adjustment to and checking up 
of the requirements of functional occlusion after mounting must be 
observed in all cases. 
33. Each fixture should be finished well and polished like a piece of 
jewelry before it is mounted. CHAPTER XVI. 
PORCELAIN BRIDGEWORK. 
The successful application of the ceramic art to the restoration of 
the crowns of teeth as single units, together with a recognition of the 
almost unlimited possibilities for achieving the highest requirements in 
esthetics, hygiene and sanitation, at one time encouraged a wave of 
enthusiasm in applying ceramics to the broader field of bridgework. 
Disaster followed in a large proportion of cases. 
Porcelain ranks first in subscribing to the requirements of esthetics, 
hygiene and sanitation. It ranks absolutely last in relation to the require- 
ments of strength. And strength is a basic and essential element in the 
replacement of missing teeth by any method. 
Hence, because of the inherent physical weakness of porcelain itself, 
porcelain bridgework is not applicable universally. It is recognized now 
only in a limited field of usefulness. 
Indications. Porcelain bridgework is limited to cases in which the 
requirements of esthetics are the primary consideration. 
And, even in cases of this type, porcelain bridgework will be successful 
only when the porcelain may be supported and protected properly and 
adequately by the superstructure itself. 
When porcelain is used under these conditions and its application is 
confined to small restorations which involve the replacement of but one, 
two, three, or, perhaps, four teeth in a single fixture, all of the advan- 
tages of porcelain may obtain successfully—but only under these 
conditions. 
Attachments. Full dowel crowns, made with platinum copings and 
platinum pin facings, or full telescope crowns, made in platinum, are the 
only types of attachments which may be used successfully in porcelain 
bridgework, due to the fact that the attachments, as well as the pontics, 
must be subjected to and must withstand successfully the degree of heat 
required to fuse the porcelain. 
Dowel Crowns. In the use of dowel crowns as attachments for 
porcelain bridgework, the strongest form of coping is obtained by making 
351 352 
CROWN AND BRIDGEWORK 
the band of 28 or 29 gage platinum, with lapped joint, as illustrated in 
Fig. 320. 
When the band has been made and fitted, as described previously, and 
trimmed to the width desired, a floor of platinum, or of iridio-platinum, 
30 to 32 gage, should be attached. The dowel then should be made of 
round iridio-platinum wire 14 to 16 gage. In enlarging the canal and in 
Fig. 320. 
perforating the floor of the coping to receive the dowel, the surplus end 
of the dowel must project through the coping at a point far enough toward 
the lingual edge of the basal surface to permit of the proper placement 
and alinement of the facing at the gingival end. 
When the coping has been completed, the bite and impression should 
be taken and the cast made. Precautions providing for the ready detach- 
ment of the coping from the cast should be taken. 
A flat-back facing, having platinum pins, then should be selected and 
ground to the desired adaptation to the coping. The coping then should 
be detached from the cast, replaced, and the relationship between facing 
and coping sustained with adhesive wax, after which they should be 
removed, invested and soldered. 
After investing, and just previous to soldering, the pins of the facing 
should be bent toward the coping in such manner as to bring them in 
contact with the surplus end of the dowel, or with the floor of the coping, 
as illustrated in Fig. 321. 
This precaution insures strength in the attachment of the facing to 
the coping and provides accommodation for a maximum of porcelain. 
And it must be remembered that the strength of porcelain increases in 
proportion as its bulk increases. PORCELAIN BRIDGEWORK 
353 
Telescope Crowns. In the use of full telescope crowns as attach- 
ments for porcelain bridgework, the band should be made of 28 gage 
platinum, with a lapped joint, as described. When fitted and contoured 
as required, the occlusal surface restoration should be made by the indirect 
Fig. 321. 
Fig. 322. 
method, and by swaging. Any necessary reinforcement of the occlusal 
surface restoration, after uniting it to the band, may be made by swaging 
a second, or duplicate piece and fitting it to the inside of this surface of 
the crown, and then attaching the two with solder. 
Adequate reinforcement may be made also by fusing porcelain over 
this surface of the crown upon the inside after the assemblage of all 
the single units composing the fixture, and at the time of baking the 
porcelain. 
No type of partial-crown restoration can be made in platinum, or can 
be used in porcelain work, except pin inlay attachments. And pin inlay 
attachments to be used in this work must be made with a platinum matrix 
and iridio-platinum pins, united with 25 per cent, platinum solder, in order 
that they may withstand the fusing of the porcelain. 
Assemblage. When the attachments are completed as single units, 
they should be placed in position on the abutments and the final bite and 
impression taken, and the cast made as previously described. 354 
CROWN AND BRIDGEWORK 
The final cast always should be made with investment compound, and 
the attachments never should be detached from the cast until after the 
final assemblage. 
Anterior Fixtures. In the construction of anterior fixtures in porce- 
lain, as soon as the cast with the attachments in position has been ob- 
Fig. 323. 
tained and mounted upon an articulator, the pontics should be selected and 
adapted. 
The labial surfaces of attachments and pontics then should be covered 
completely with investment compound, after which the cast should be re- 
moved from the articulator and the whole trimmed down until just large 
enough to sustain the relationship of the various units and to insure 
strength. 
When the investment has been trimmed to the size and outlines desired, 
the lingual surfaces of copings and facings should be exposed freely, as 
illustrated in Fig. 322 A. 
Round iridio-platinum wire, about 16 gage, then should be fitted care- 
fully in such manner as to rest firmly upon the basal surface of each 
coping, and to afford close contact with each pontic and each pin, as 
illustrated in Fig. 322 B. If contact between the pins and the assembling 
wire does not obtain easily, each pin should be bent to close contact; and 
the assembling wire should be placed in close apposition to the facings 
in order that it may offer no interference with the restoration of the 
desired lingual contour in porcelain. When the assembling wire has 
been fitted in this manner, the case then should be heated and each point 
of contact soldered in such manner as to insure strength. PORCELAIN BRIDGEWORK 
355 
After the assemblage has been completed, the case should be allowed 
to cool slowly, then removed from the investment, cleaned in the acid 
bath, and finished roughly with stones and disks. All sharp edges and 
angles of assembling wire and pins should be rounded nicely and every 
opportunity for the restoration of contour with porcelain should be 
afforded. 
Typical cases, involving the replacement of missing anterior teeth, 
together with structural requirements, are illustrated in Fig. 323. 
Fig. 324. 
Through the tendency of the natural teeth to migrate toward an 
edentulous area, a condition in which a single abutment must be required 
to support two pontics, presents occasionally. In such cases the best 
results may be obtained by sacrificing the remaining natural crown of the 
abutment tooth, and using its root with a single coping as a means of 
replacing its own crown, together with the missing tooth. (Fig. 324.) 
In cases of this type the best results are obtainable with porcelain. 
When the coping has been made of platinum, as indicated, it should be 
placed in position upon its supporting root, the bite and impression taken, 
and the cast made of investment compound. 
When the cast has been obtained, platinum pin facings of the proper 
color and size should be selected and ground to the required adaptation. 
Then they should be soldered to the coping, taking all precautions pre- 
viously indicated, after which the desired contour may be obtained in 
porcelain. By using gum enamel, any display of the platinum coping 
between the gingival ends of the facings may be avoided. Esthetic fea- 
tures not to be obtained in any other manner are possible in cases of this 
character. 356 
CROWN AND BRIDGEWORK 
Restoration of Gingival Tissue. In cases of extensive loss of tissue 
as a result of surgical procedure, or of long-continued absorption, and 
as a means of subscribing to the esthetic demands of the individual case, 
particularly in the replacement of single missing anterior teeth, some 
restoration of the gingival tissues is often necessary. 
The politics, in such cases, must never appear to be longer than the 
crowns of the remaining natural teeth. Therefore, if esthetic results 
Fig. 325. 
Fig. 326 A. 
Fig. 326 B. 
are to be secured, a restoration of the gingival tissue must be made with 
gum enamel, and this should be done previous to assembling the pontic 
and its attachments. 
This restoration is easily constructed by selecting the facing to meet 
the requirements of the case (Fig. 325 A), and then building the neces- 
sary restoration with gum enamel, subsequently grinding the restoration 
to conform to the adaptation. (Fig. 325 B.) PORCELAIN BRIDGEWORK 
357 
Any type of facing having platinum pins may be used, and one slightly 
longer than necessary facilitates the procedure. In building such restora- 
tions, two and sometimes three, bakes will be required, and any of the 
gum enamel bodies which produce the color desired may be used. 
Less extensive, but equally typical conditions of this type are illus- 
trated in Fig. 326 A. A more extensive restoration, involving the re- 
placement of two teeth, together with the structural requirements, is 
illustrated in Fig. 326 B. 
Fig. 327 A. 
Fig. 327 B. 
Fig. 327 C. 
While a saddle of any form, or shape, is indicated rarely in the con- 
struction and application of fixed bridgework for sanitary reasons; still, 
if gingival restoration is demanded the adaptation is facilitated by the 
use of a very thin gage of platinum adapted to the proper outlines pre- 
viously by burnishing, or by swaging, and making it a part of the struc- 
tural formation of the fixture. 
Posterior Fixtures. The successful application of porcelain in pos- 
terior restorations is limited to small fixtures only, owing to the increased 
demands of occlusal stress. 
The replacement of missing first bicuspids by attachment to a dowel 
crown restoration on the second bicuspid, may be made successfully if 
provided with a lingual rest, as illustrated in Fig. 327 A. And the re- 358 
CROWN AND BRIDGEWORK 
placement of a missing second bicuspid, by attachment to a dowel crown 
restoration on the first bicuspid, also may be made successfully if pro- 
vided with an occlusal support resting in an inlay in the first molar, as 
illustrated in Fig. 327 B. 
In the latter type of fixture, if the second bicuspid pontic must present 
an occlusal surface restoration, then a small saddle must be used to 
support the restoration, and the pontic must be built as a single unit, as 
illustrated in Fig. 327 C. But, if occlusal surface restoration is unneces- 
sary, or if a simple facing may meet the requirements, then the use of a 
saddle may be avoided, and a more sanitary type of fixture will obtain. 
Fig. 328. 
Fig. 329. 
Use of Saddles. 
In more extensive cases where the esthetic requirements may be 
extraordinary, demanding the use of an all-porcelain fixture, even though 
its application is made at the expense of some of the requirements of 
sanitation, results, successful in every other particular, may be obtained. 
But successful results in posterior restorations, which involve and 
require a reproduction of the occlusal surfaces of the pontics, are obtain- 
able only by means of a saddle resting firmly upon the mucosa beneath 
each and every pontic. In such cases complete absorption of the edentu- 
lous tissue must present, primarily, and the use of a saddle would be, 
then, but another instance of a choice of evils. 
The attachments should be completed first, in effecting the required 
accuracy of adaptation of a saddle in the construction of fixed bridge- 
work in porcelain. Upon completion, they should be placed in position PORCELAIN BRIDGEWORK 
359 
on the abutments and an impression taken in plaster. In removing the 
impression, the attachments may, or may not, be removed with it. If 
they are removed with the impression, they should be detached there- 
from, and laid aside. The impression then should be allowed to dry 
thoroughly, and each end filled in, either with plaster or moldine. 
The impression, prepared in this manner, then should be poured with 
fusible alloy, which afifords an accurate die. A counter-die then should 
be made, also with fusible alloy, as described previously, and as illustrated 
in Fig. 328. 
The saddle then should be formed by swaging, using platinum of about 
30 gage. When swaged, the saddle should be trimmed in such manner 
Fig. 330. 
as to conform to the gingival outlines and to support the occlusal restora- 
tion of each individual pontic, with a minimum of connecting surface 
between each pontic and each attachment, as illustrated in Fig. 329. 
When the adaptation and desired outlines have been secured, the at- 
tachments should be placed in position on the abutments, the saddle placed 
and held firmly in its relation to the mucosa, and an impression taken 
in plaster. 
It is imperative that the saddle should bear firmly against the mucosa 
while taking the impression. This may be accomplished easily by fitting 
an orange-stick wedge closely between the respective attachments first, 
and then forcing the saddle to place with adhesive or base-plate wax, or 
temporary stopping, as illustrated in Fig. 330. 
When the impression, in plaster, has been taken, it should be varnished 
properly and filled with soldering investment compound. When the cast 
has been separated from the impression the relationship between attach- 
ments and saddle should be sustained permanently by soldering. When 
attachments and saddle have been joined by soldering, the fixture should 
be cleaned in the acid bath, replaced in position on the abutments and 
the final bite and impression taken. 360 
CROWN AND BRIDGEWORK 
The cast should be made of soldering investment compound and, when 
mounted upon the articulator, the pontics should be selected and ground 
to the desired adaptation and relationship with the attachments and to the 
saddle. The case then should be invested for the final assemblage with 
solder. The assembling wire should be fitted carefully and the fipal 
soldering completed. 
The structural requirements and the completed fixture in a typical case 
involving the application of porcelain, with a saddle, to the construction 
of posterior fixtures in the upper arch, are illustrated in Fig. 331. 
Fig. 331. 
Fig. 332. 
In the lower arch, all requirements of a saddle, with a more sanitary 
type of construction, may be obtained frequently by the use of a half- 
round, or “D’’ wire of about 12 gage, with the convex surface adapted 
directly to the summit of the edentulous area between the attachments. 
The convex surface adapted to the edentulous ridge affords a fairly sani- 
tary result, while the flat surface affords all support necessary to the 
occlusal surface restoration of the pontics with porcelain. 
In the construction of a fixture of this type, the adaptation of the 
half-round wire may be made with pliers, instead of by swaging, and since 
the same close adaptation required of a saddle, as applied to the preceding 
type for the upper arch, is not required of this type in the lower arch, 
an impression under pressure is not necessary. In fact, the wire, used 
in this manner and for this purpose, may be adapted and soldered di- 
rectly upon the first cast. A final impression and cast then will afford 
opportunity for the adaptation of the pontics, the fitting of the assembling 
wire, and the final soldering. 
The structural requirements and the completed fixture in a typical 
case, made in this manner, are illustrated in Fig. 332. PORCELAIN BRIDGEWORK 
361 
Combination Gold and Porcelain Bridgework. 
In many instances, the advantages of gold and porcelain may be 
combined successfully in a single fixture. 
Dowel Crowns. Dowel crowns, made with a platinum coping and 
built of porcelain, may be used successfully as an attachment, in cases 
where it may be desirable to use pontics of some other type, and to com- 
plete the fixture with gold. 
In the use of a porcelain dowel crown as an attachment for bridge- 
work, the presentation of a liberal surface of the platinum coping toward 
Fig. 333- 
the adjacent pontic, or pontics, is necessary as a means of affording ample 
opportunity for soldering and of insuring adequate strength. This pro- 
vision is obtained easily by soldering an additional rim of platinum, 28 
gage, to the periphery of the basal surface of the coping at the time of 
soldering the facing. (Fig. 333 A.) The crown then may be completed 
with porcelain as a single unit (Fig. 333 B), and subsequently assembled 
to the fixture, as described previously; and in accordance with the re- 
quirements and without danger to the porcelain if the usual precautions 
are observed. 
Gold Crowns. Full, or partial telescope crowns, made in gold, may 
also be used as attachments for porcelain bridgework by building the 
porcelain part of the fixture to fit them, but independent of them, and 
subsequently uniting them with solder. 
If all other parts of the fixture must be built in porcelain, and must go 
through the furnace, very little advantage is gained from the use of full 
telescope crowns made in gold, as platinum would answer the same purpose 
in most cases; but some advantage may be obtained by the use of partial 
crowns made in gold in this manner. 
When the body of the fixture must be built in porcelain, and when it 
is desirable to use as an attachment some type of partial crown which 362 
CROWN AND BRIDGEWORK 
can be made only in gold, the attachments should be made and finished 
first as single units. The porcelain section then should be made in accord- 
ance with the requirements, and constructed to assume the desired rela- 
tionship with the attachments, and to include in its structural design the 
presentation of a freely exposed surface of platinum, adequate to the 
requirements of soldering and of strength, as illustrated in Fig. 334 A. 
Fig. 334 A. 
Fig. 334 B. 
When this provision has been observed properly and adequately, the 
porcelain section should be finished separately, after which the relation- 
ship between porcelain and gold units, whether full or partial crowns, 
should be sustained by means of an impression, the cast made with in- 
vestment compound, the porcelain section further invested and protected 
properly, the case heated carefully and assembled with solder. (Fig. 
334 B.) 
Making Porcelain Sections. It is necessary frequently to make 
porcelain sections, or “gum blocks,” particularly in the replacement of 
missing anterior teeth. In many cases of extensive loss of tissue as a 
result of the early or premature extraction of the natural teeth, or as a 
result of surgical procedure, the restoration of lost tissue, as well as the PORCELAIN BRIDGEWORK 
363 
replacement of missing teeth, is demanded. And when the restoration 
of lost tissue is demanded, a porcelain section, restoring the lost tissue with 
gum enamel, is the only means by which a high order of esthetics may 
be satisfied. 
Porcelain sections, with gum enamel restoration, to be used with at- 
tachments made in gold, may be built easily and successfully. The at- 
tachments to be used in the fixture should be made and finished as single 
Fig. 335 A. 
Fig. 335 B. 
units first. Then they should be placed in position on the abutments and 
an impression taken in plaster. A cast made in plaster is here preferable 
for the reason that it presents a smoother and, therefore, a more accurate 
surface. 
When the cast has been obtained, platinum pin facings of proper size, 
type and color, should be selected and ground to the adaptation desired. 
Their relationship should be sustained temporarily with adhesive wax. 
The labial or buccal surface of the facings then should be covered freely 
with investment compound in such manner as to sustain the relationship 
securely, and yet admit of their removal from the plaster cast. 
When the investment has crystallized, facings and investment should 
be detached from the cast. Round iridio-platinum wire, about 16 gage, 364 
CROWN AND BRIDGE WORK 
should be fitted to a close contact with each facing at the desired point 
between pins and gingival edge. If contact with all pins does not obtain, 
each pin should be bent toward the assembling wire until in contact with 
it. A flange of platinum plate, about 28 gage, then should be fitted to each 
end of the wire and sustained in contact by the addition of a small bit 
of investment compound. The case then should be heated thoroughly 
and each point of contact soldered securely. 
When the facings are assembled permanently in this manner, all sharp 
points and edges of platinum should be rounded nicely and finished smooth. 
The flanges at the mesial and distal ends of the assembling wire will 
afford a soldering surface and insure strength in the final assemblage to 
the attachments with solder. (Fig. 335 A.) 
In building* the restoration with gum enamel, accuracy of adaptation 
is obtained by covering this portion of the cast with thin tin foil first, 
and lubricating the foil with vaseline. The assembled facings then 
should be placed in position on the cast and the contour and restoration 
desired made by filling in between the tin foil and over and around the 
gingival ends of the facings, and over and around the assembling wire 
and the pins, with porcelain body of a color similar to the color of the 
facings. 
When the desired shape and contour has been obtained, the section 
should be detached from the cast carefully. Detachment is facilitated by 
lubricating the tin foil, but should the foil cling to the porcelain body, 
it should be teased away gently. The section now should be fixed in 
some form of fire-clay support, placed in the furnace and the added porce- 
lain fused until well but not highly vitrified. All cracks and crevices 
which present after the primary bake, as a result of shrinkage, should 
be moistened and a second application of the same body made and 
fused. 
Gum enamel body, of the color desired, now should be applied in 
sufficient thickness to insure the form and color required. The case 
then should be fused. Three bakes will be required; more are seldom 
necessary. Some difficulty may be experienced in procuring a gum 
enamel body of proper color, but the color desired must be obtained by 
experimentation and should be satisfactory before using. 
When the section has been finished and fitted to the original plaster 
cast, the attachments then should be removed from this cast, placed in 
position on the abutments and a final impression taken in plaster. This 
impression should be poured with investment compound and the resulting 
cast used for the final assemblage of the section to the attachments with 
solder, as previously described. PORCELAIN BRIDGEWORK 
365 
Some idea of the esthetic possibilities obtainable from making porce- 
lain restorations in sections for unusually exacting cases is presented in 
Fig. 335 B. 
Basic Requirements. 
In the construction of porcelain bridgework several basic require- 
ments are essential to successful achievement and must be observed. 
They are as follows: 
First: Platinum, or the alloy of iridio-platinum, must be used 
throughout the building of the superstructure. 
Second : All joints must be soldered with 25 per cent, platinum solder, 
or with pure gold. 
Third: If pure gold is used as a solder, it must be fused thoroughly, 
and fused until alloyed with the platinum. 
Fourth: In assembling the fixture, close contact between all parts 
to be united must obtain. 
Fifth: All of the strength required in the finished fixture must exist 
in the superstructure itself, and no sharp angles should present. 
Sixth: Flat-back facings having platinum pins should be used. 
Seventh: Porcelain must be used for esthetic purposes only, and 
must be supported and protected against stress in every direction. 
Eighth: The higher-fusing porcelain compounds are strongest and, 
hence, should be used exclusively. 
Ninth: While two and sometimes three bakes are necessary, the 
desired color, contour and carving, with allowance for shrinkage, should 
obtain in the primary bake. 
Tenth: In placing the piece in the furnace, it should be deposited 
in the center of the muffle, with all surfaces of porcelain presenting toward 
the opening. Principles and Technics of 
Removable Bridgework. 
CHAPTER XVII. 
REMOVABLE BRIDGEWORK. 
In combining the replacement of missing teeth with tissue restoration, 
the type of construction known as “removable” bridgework has a distinc- 
tive field of usefulness. It affords an opportunity for meeting the highest 
physiological and sanitary requirements, and demands all of the dental 
engineering skill and craftsmanship which is called for in the application 
and construction of fixed bridgework. 
Due to the recognized importance of oral hygiene and of the ever in- 
creasing demands of prophylaxis, the psychology of removable bridge- 
work is almost magical. 
Any effort directed toward, or which will aid in the promotion and 
maintenance of health is progressive and constructive, and is essential to 
successful achievements. But removable bridgework is not a panacea for 
all of the ills attached to the replacement of missing teeth by other 
methods; nor is it the only rational method of procedure. 
Except in edentulous mouths, all methods of replacing lost teeth are 
but a choice of evils. All require, or result, in more or less injury to 
the supporting and remaining natural teeth. And the application of 
removable bridgework demands, primarily, quite as much mutilation, and 
results eventually in quite as much injury as does any other method. As 
an intermediary between fixed bridgework and clasp dentures, however, 
it is a useful mode of procedure. 
Removable structures are more sanitary than fixed bridgework, though 
less efficient in the restoration of function. Yet they are often more 
efficient and less of a mechanical incumberance than clasp dentures. 
Removable bridgework comprises an assemblage of abutment and re- 
taining attachments. It embraces that type of construction, in which the 
body of the fixture which supports the missing teeth and restores lost 
tissue, rests firmly upon the edentulous tissues, and is held in position by 
366 REMOVABLE BRIDGEWORK 
367 
means of retaining attachments which are supported by the abutment 
teeth. 
The retaining attachments are agencies through which the structure is 
retained in position and stabilized when functioning and which also permit 
of removal and replacement. 
This type of construction is not the product of modern development. 
To a large extent it is the heritage of misapplied and unsuccessful fixed 
bridgework; the outgrowth of a recognition of the limitations of fixed 
bridgework and of the ever increasing and more exacting demands of 
sanitation. 
During the evolution of removable bridgework, the art of supplying 
missing teeth has been “revolutionized” many times by the introduction of 
“new” forms of retaining attachments. At the time of their introduction, 
most of them were heralded as revolutionary methods of procedure, 
applicable universally. Most of them were soon abandoned without seri- 
ously retarding the progress of dentistry. Many have been forgotten. 
None were, or are, applicable universally. 
Removable bridgework is a useful method of procedure in proportion 
as the indications for it are favorable, and as the application may be 
made skilfully. 
But, unless the indications are favorable, and unless all operative and 
mechanical details of construction are minutely and skilfully executed, 
removable bridgework will do as much irreparable injury to the supporting 
teeth and to their investing tissues as will result from the use of any 
other method of replacing missing teeth. 
It is probable that quite as many good teeth have been lost through 
the indiscriminate and unskilful application of removable structures as 
have been lost because of similar application of other methods. Hence, 
notwithstanding its advantages, it is not to be regarded as a universal 
method of procedure. 
Advantages. When used with discrimination, however, and when 
built and adapted skilfully, removable bridgework possesses many advan- 
tageous features, as follows: 
First: The replacement of missing teeth may be combined with the 
restoration of lost tissue in a manner which subscribes to the highest 
requirements of sanitation. 
Second: The normal functioning activity of the abutment teeth is 
restricted to a minimum extent only. 
Third: A minimum of contact with the mucosa and a minimum of 
mechanical incumberance is required. 368 
CROWN AND BRIDGEWORK 
The first advantage enumerated is an important consideration, because 
every opportunity for affording and for insuring sanitation must present 
in all cases when the replacement of missing teeth and the restoration of 
lost tissue is demanded. 
The second feature is important also for the reason that a more 
physiologically ideal condition undoubtedly obtains, especially in large fix- 
tures, when the replacement and restoration may be made in a manner 
which will not interfere appreciably with the normal functioning move- 
ment of the supporting teeth. 
And the third feature is important because a minimum of mechanical 
incumbrance is desirable at all times and in all cases. 
All of these features may be obtained in the use of well designed, well 
constructed and well adapted removable bridgework. And, when indi- 
cated, no other method of procedure offers quite the same opportunities, 
or answers quite the same purposes. 
Indications. Generally, removable bridgework is indicated whenever 
fixed bridgework is contraindicated; or, specifically, whenever fixed 
bridgework is contraindicated, some type of removable structure is 
demanded. 
Clasp dentures might answer the same purpose. Structures of this 
latter type are simpler, more economical, and require no mutilation of the 
supporting teeth; but they offer a degree of mechanical incumbrance 
which is minimized or eliminated entirely by removable bridgework. 
The indications for the rational use of removable bridgework embrace 
the following classes of cases: 
First: In cases where the number of missing teeth to be replaced 
greatly exceeds the number of remaining natural teeth which may be used 
as abutments. 
Second: Where the distribution of abutment teeth is unfavorable 
to the mechanical requirements of a fixed structure. 
Third: Where the restoration of lost tissue demands the use of a 
saddle, and where the requirements of sanitation demand a removable 
structure. 
Requirements. The successful application of removable bridgework 
depends, primarily, upon two basic requirements: First, upon the appli- 
cation of sound mechanical principles; and second, upon the development 
of a high order both of operative and mechanical skill. 
If these basic requirements in the composite may not be evidenced at 
all times, then removable bridgework should not be attempted, because REMOVABLE BRIDGEWORK 
369 
the operative part of the procedure is equally or even more exacting and 
cannot be consigned to expert dental laboratory technicians. 
Study Casts. A careful study of the composite requirements of each 
and every case always must precede the selection of the particular method 
of procedure which is adapted best to each individual case. No two cases 
are alike and no one method is applicable universally. Hence, in order 
to make an intelligent selection, study casts which include all of the re- 
maining natural teeth in both arches must be made and used in all cases. 
Abutment Teeth. In the replacement of more than two missing teeth 
and, particularly, in all structures which involve the bilateral or complex 
type of construction, the selection of the abutment teeth is an important 
consideration. In all cases the selection must be made carefully, and 
always with a view of obtaining the maximum degree of efficiency, 
permanency and comfort in the restoration. To this end, health, stability 
and favorable distribution are vital factors. 
Retaining Attachments. The selection of the type of retaining at- 
tachment which is best adapted to the requirements of each case is also 
an important consideration and must be made carefully. 
Since no one type of retaining attachment is applicable universally, an 
intelligent selection cannot be made without a knowledge of the respective 
advantages and disadvantages of each type. This knowledge is essential, 
for the reason that different types of retaining attachments are indicated 
often in the same structure. Indeed, in the use of two different types of 
retaining attachments in the same structure, parallelism often may be ob- 
tained more easily and with equal stability and sometimes with even 
greater resistance to stress. 
Saddles. Irrespective of the size of the structure, the shape and 
formation of the saddle and its adaptation to the edentulous tissues are 
important features in all cases. 
Assemblage. The assemblage of the saddle and of the retaining at- 
tachments in their proper relationship with the supporting abutments is 
the most exacting and the most difficult detail on the construction and 
successful application of removable bridgework. 
The stress imposed upon the abutment teeth, the strength of the re- 
taining attachments, and the efficiency of the structure all depend upon 
the degree of accuracy with which this procedure is executed. Hence, 
close attention to detail and exactness are demanded at all times. 370 
CROWN AND BRIDGEWORK 
Retaining Attachments. 
Several different types of retaining attachments are used successfully 
in the construction of removable bridgework. These vary somewhat in 
design, but all consist of two parts, one of which engages the other. One 
of these parts is attached securely to the abutment tooth and the other 
to the removable structure. 
All of the various retaining agencies now used may be grouped in 
two general classes and designated as “vertical” attachments and “hori- 
zontal” attachments. They may be so designated because of the relation- 
ship which the surfaces of frictional contact bear to the long axes of the 
supporting teeth. 
Requirements. If the highest possibilities of successful removable 
bridgework are to be attained, the retaining attachments must subscribe 
to the following requirements: 
First: The area of frictional contact of all retaining attachments 
should be confined within the circumference of the supporting abutment 
tooth. 
Second: The stress assumed by the retaining attachment should be 
imposed upon the abutment tooth in a line parallel with its long axis. 
Third: All retaining attachments must be mutually parallel and must 
retain the structure by frictional contact, and not by binding one against 
the other, nor by the displacement of the abutments. 
Fourth: Strength adequate to the demands of occlusal stress must 
exist in all forms of retaining agencies. 
Fifth: Some provision, or opportunity for tightening, or for over- 
coming the loss of frictional contact between the surfaces, by wear, should 
present always. 
Any retaining agency which extends or projects beyond the periphery 
of the abutment tooth to any appreciable extent acts as a lever of the first 
class and imposes abnormal stress. And any great degree of abnormal 
stress, continued indefinitely, will induce absorption and result in failure. 
Vertical Attachments. 
That class of attachments which may be designated as vertical attach- 
ments embraces all types of retaining devices in which the greatest area 
of frictional contact between the telescoping parts is in a line parallel with 
the long axis of the supporting tooth. 
Three different types of retaining attachments now in use may be 
placed in this class, as follows: REMOVABLE BRIDGEWORK 
371 
First: That type which consists of a friction plate of some form or 
shape which engages in a close-fitting, bucco-lingual jacket. 
Second: That type which consists of a split-post which engages in 
a close-fitting seamless tube. 
Third: That type which consists of two full crown restorations, one 
of which telescopes over the other. 
Friction Plate and Jacket Attachments. 
The type designated as friction plate and jacket retaining attachment 
is the smallest and the most generally useful retaining device. Several 
Fig. 336 A. 
Fig. 336 C. 
Fig. 336 B. 
designs of attachments of this type are used now, and while the shape 
and form of the friction plate varies somewhat in each type, yet all 
are similar and all involve the same principle. The friction plate tele- 
scopes bucco-lingually into a close fitting jacket. One of the original 
forms of this type of attachment is illustrated in Fig. 336 A. The 
jacket is shown in “A,” and the friction plate in “B.” 
One of the more modern types is illustrated in Fig. 336 B, and another 
type showing a variation in design, and known as the Roach attachment 
is illustrated in Fig. 336 C. 
Indications. Retaining attachments of this type may be used suc- 
cessfully in a large variety of cases. They are made usually in a gradation 372 
CROWN AND BRIDGEWORK 
of sizes adaptable to the varying dimensions of the crowns of natural 
teeth and of an alloy of iridio-platinum, or of some other especially hard 
alloy. Being the smallest type of retaining attachment, they are ap- 
plicable both to inlay and full crown restorations, and to teeth having 
vital pulps, as well as to pulpless teeth. 
Split-Post and Tube Attachments. 
The second type of vertical attachment is known as the split-post 
and tube attachment. This type consists of a split-post which engages in 
Fig. 337- 
Fig. 338. 
a closely fitting tube. The post is made by bending a half round or “D” 
shaped wire over upon itself with the flat surfaces approximating each 
other and then drawing it down to the size desired, thus forming a 
“split”-post. The tube is seamless, with one end closed. Both split-post 
and tube are made of iridio-platinum alloy, the post being especially hard, 
and are made in sizes of varying diameter. (Fig. 337.) 
Indications. Retaining attachments of this type are adaptable to and 
especially useful in two different classes of cases: First, in those cases 
in which a pulpless tooth, or root, is used as an abutment; and, second, 
in cases of assembled abutments. 
As applied to the roots of teeth, this type of attachment can be used 
successfully only in cases where the diameter of the root is sufficiently 
large to accommodate a split-post and tube of such size as will insure 
adequate strength. This requirement is essential to the strength both 
of the supporting root and the removable structure and limits the applica- 
tion almost entirely to the roots of the upper central incisors, cuspids 
and second bicuspids and to the lower cuspids and bicuspids. REMOVABLE BRIDGEWORK 
373 
Full Telescoping Crown Attachments. 
Full telescoping crown attachments also are a useful type of retaining 
agency. They consist of a basic coping having axial walls which are 
slightly inverted from the gingival line to the occlusal angle, and a per- 
fectly flat occlusal surface. The basic coping is to be attached to the 
supporting natural tooth crown. A full crown restoration which meets 
all of the requirements of contour and of occlusion is made then to 
Fig. 339- 
telescope over and fit closely to the basic crown, and this is attached 
subsequently to the removable fixture. 
Indications. This type of retaining attachment is indicated particu- 
larly in the restoration of molar teeth where full crown restorations may 
be used, or may be demanded. It is applicable to teeth having vital pulps 
as well as to pulpless teeth. Both basic and telescoping restorations which 
constitute this type of retaining agency are illustrated in Fig. 338. 
Horizontal Attachments. 
Retaining attachments which belong to that class designated as the 
horizontal type, differ from those of the vertical type in form and shape, 
in that the greatest area of frictional contact between the two parts con- 
stituting the attachment engages the supporting tooth in a line horizontal 
with its long axis. 
Attachments of this type consist of a friction bar and a close fitting 
jacket, and the relationship with the supporting abutment tooth neces- 
sarily demands that a large portion of the occlusal surface of molar teeth 374 
CROWN AND BRIDGEWORK 
be involved, the entire occlusal surface of bicuspid teeth and the entire 
lingual surface of the six anterior teeth, and the mesial or distal, or both 
the mesial and distal surfaces, to an extent, or depth, sufficient to imbed 
the attachment within the normal contour of the tooth. 
The friction bar may be split or solid. It is attached to the fixture 
and interlocks into the jacket in such manner as to preclude mesio-distal 
displacement, while any appreciable degree of bucco-lingual movement is 
overcome by imbedding the jacket in an inlay or full crown restoration of 
some type. 
Indications. Retaining attachments of this type are useful when the 
application may be made to pulpless teeth, but have a very limited field 
of usefulness as applied to teeth having vital pulps. Indeed, any form 
or type of retaining device which demands pulp destruction, involves 
procedure which closely approaches the border line of malpractice, and, 
hence, is of doubtful utility. A typical application of attachments of 
this type is illustrated in Fig. 339. 
Saddles. 
In removable bridgework that part of the structure which rests upon 
the edentulous area, supports the pontics, and affords the means of obtain- 
ing the desired restoration of lost tissue, is called the saddle. While this 
part of a removable structure may be made in vulcanite, the best results, 
from the combined viewpoints of certainty, accuracy and strength, are 
obtained from the use of gold or of platinum. 
Requirements. Next to the retaining attachments, the saddle is the 
most essential part of removable bridgework. It must subscribe to the 
following requirements: 
First: It must be adapted closely to and rest firmly upon the subjacent 
mucosa. 
Second: It must be retained securely in its relationship to the mucosa 
by parallel attachments which engage parallel abutments. 
Third : It must cover an area sufficiently large to stabilize the structure. 
Fourth: The size and outline will vary with, and must be governed 
by the number of missing teeth to be replaced. 
Fifth: It must not encroach upon the gingival tissues surrounding 
the abutment, nor upon the adjacent natural teeth. 
Sixth: It must be muscle trimmed and present no sharp edges. 
Seventh: It should be no thicker, nor heavier, than the requirements 
of restoration and strength demand. REMOVABLE BRIDGEWORK 
375 
Vulcanite Saddles. Because of the difficulty of sustaining and main- 
taining the proper relationship between the attachments and the saddle, 
no type of vertical, nor horizontal retaining attachment is applicable suc- 
cessfully with vulcanite saddles. 
In cases demanding extensive restoration of lost tissue, and, some- 
times, for purely economical reasons, vulcanite saddles may be indicated; 
but when indicated, or when used for any reason, all retaining attachments 
must be united previously by a basic structure, and in such manner as to 
insure proper relationship and adequate strength independent of the saddle. 
And even then it is necessary further to take every precaution which 
will insure a maintenance of this relationship on, and with, the cast during 
flasking, packing and vulcanizing. 
Construction. 
In the construction of removable bridgework of any type, success or 
failure will depend largely upon careful technic and absolutely accurate 
parallelism between the retaining attachments. 
Many types of retaining attachments are useful and, to a greater or 
less extent, special technic is involved in the application of each respective 
type. But, since no one type is.applicable universally, no one line of 
technical procedure is applicable, likewise, only insofar as basic principles 
are concerned. It is essential, therefore, that the operator should have a 
knowledge of basic principles. 
Any variations in technical procedure which are applicable only to 
the particular type of retaining attachment selected are useless as applied 
to any other type. More or less elaborate instructions are furnished by 
the manufacturers of each type. Therefore, in the selection and applica- 
tion of retaining attachments to be used, the special technic recommended 
in their use, should be followed closely. 
For these reasons, basic principles, only, as pertain to the application 
of all types of retaining agencies, in general, and to the requirements of 
parallelism, in particular, need be considered. 
Paralleling Retaining Attachments. 
Removable bridgework of any type and structures of any size require 
two retaining attachments. Seldom more. These may be of the same type 
or of different types, but absolute parallelism between them must be se- 
cured ; and absolute parallelism is not obtainable by the eye, alone. Hence, 
an accurate paralleling instrument must be used at all times and in all 
cases, irrespective of the type of retaining device used. 376 
CROWN AND BR1DGEWORK 
A paralleling instrument must be accurate, and to he accurate it must 
be perfect mechanically. It also must include alinement posts which 
terminate in an exact reproduction of the friction plate, post, or bar 
Fig. 340. 
Fig. 341 A. 
which constitutes the basic part of all types of retaining device. And 
these terminals must engage the jackets in exactly the same manner and 
with all of the accuracy with which the jackets are engaged by the friction 
plate, post, or bar, itself, except to allow for just enough play to permit 
of the detachment of one from the other with facility. 
Because of the exacting requirements in this connection, no type of 
retaining attachment can be used successfully, unless an accurate parallel- 
ing instrument is provided for or adapted to its special use. REMOVABLE BRIDGEWORK 
377 
Fig. 341 B. 
Fig. 341 C. 378 
CROWN AND BRIDGEWORK 
The simplest form of paralleling instrument, showing its applica- 
tion, is illustrated in Fig. 340. A more mechanically perfect instrument, 
designed by Dr. L. J. Weinstein, is illustrated in Fig. 341 A. Another 
known as the Brown-Maier in Fig. 341 B, and the Chayes “parallelometer” 
in Fig. 341 C. The three latter instruments are accurate, mechanically, 
and have a wide range of usefulness. 
Fig. 342. 
Fig. 343- 
Application of Vertical Attachments. 
Retaining attachments of the vertical type are the most generally use- 
ful retaining agencies. Being of the smallest proportions and dimensions 
consistent with the requirements of strength, they occupy the least space 
and, hence, are applicable to teeth having vital pulps, as well as to pulpless 
teeth. 
Vertical retaining attachments may be used successfully in connection 
with inlays, dewel, or full telescope crown restorations. 
Inlays. Because of the advantages obtainable from any method of 
procedure which permits of pulp conservation, the use of retaining attach- 
ments of the vertical type, in connection with inlays, offers the greatest 
range of application and the broadest field of usefulness. (Fig. 342.) 
Cavity Preparation. In the application of retaining attachments to 
inlays, all the basic requirements of cavity preparation, in general, must 
be observed. REMOVABLE BRIDGEWORK 
379 
Since the jacket should and must become a component part of the 
inlay, the cavity must be prepared in such manner and should be of such 
size as to accommodate the jacket within the circumference of the natural 
tooth crown, and to insure adequate strength and secure fixation. And 
adequate strength and secure fixation will not obtain unless the inlay is 
seated squarely, interlocked mechanically, and supported properly by 
good, strong cavity walls and margins. 
Fig. 344- 
Inlays which will accommodate the placement of the jacket for any 
of the various friction-plate and jacket attachments, and which will permit 
the jacket to become a component part thereof, may be made successfully 
and in a simple manner by the use of the indirect method, and by casting, 
though matrix inlays may be used successfully and in similar manner. 
Casting. In making inlays which are to accommodate the retaining 
jacket by the indirect method and by casting, a shell inlay, only is re- 
quired. No effort to accurately restore contour need be made primarily. 
A shell inlay affords all the accuracy of adaptation to the cavity walls 
and margins which is demanded and permits of and facilitates the correct 
placement of the jacket. The restoration of the inlay to the normal out- 
lines and the occlusal requirements of the supporting natural tooth crown 380 
CROWN AND BRIDGEWORK 
is made subsequently and at the time of attaching the jacket to the shell 
inlay with solder. In large inlays, such as are possible in pulpless teeth, 
the jacket and shell inlay may be united and the contour completed by 
casting, thus obviating an excess of solder. Previous to making the shell 
Fig. 345- 
inlay, the selection of the retaining attachments to be used must be made 
and should be of a size proportionate with the dimensions of the crown of 
the supporting natural tooth. 
In the selection of the attachments to be used, it is necessary to make 
sure that the cavity preparation embraces a bucco-lingual marginal exten- 
sion which will permit the inlay to accommodate the jacket freely, and 
without involving or encroaching too closely upon its buccal and lingual 
margins. 
When these features have been observed, a unit impression should 
be taken in hard impression compound and an amalgam cast made, as 
described previously. When the amalgam cast has been obtained, the 
cavo-surface and margins should be lubricated, and a hard casting wax 
melted and a thin coat painted over all surfaces of the cavity and just 
slightly overlapping upon all margins. (Fig. 343 A.) REMOVABLE BRIDGEWORK 
381 
All surplus thickness beyond that sufficient to permit of the attach- 
ment of a sprue-former at some convenient point should be trimmed 
off, observing particularly that accommodation for the jacket exists. This 
thin shell inlay, then, should be teased loose, the sprue-former attached 
(Fig. 343 B) and the inlay cast, using a good grade of casting alloy. 
Fig. 346. 
After casting, the inlay should be boiled in dilute hydrochloric acid, 
fitted to position on the amalgam cast and finished to the point of polishing. 
When two attachments of the same type are used in one fixture, both 
shell inlays should be made in similar manner and at the same time. A 
final adaptation then should be effected directly upon the supporting nat- 
ural tooth and all margins finished as desired. When the thin shell inlays 
are completed, they should be placed in position in the supporting natural 
teeth. (Fig. 344.) An impression then should be taken in plaster. 
The inlays should be removed with the impression, but their correct 
relationship therein must be insured. The impression should be varnished, 
and then filled, using a high grade of cast-plaster. 382 
CROWN AND BRIDGEWORK 
When the resulting cast with inlays in position has been obtained, all 
exposed surfaces of the inlays should be cleaned with alcohol and the 
jackets of the retaining attachments then adjusted to alinement posts on 
the paralleling instrument and placed accurately in the inlays. (Fig. 345.) 
When the adjustment of both jackets and their respective inlays has been 
obtained with accuracy, the desired relationship between inlays and jackets 
should be retained securely with adhesive wax. When the wax has been 
Fig. 347. 
chilled with cold water, the alinement posts should be detached carefully. 
(Fig. 346.) As a means of facilitating this detachment, the terminals of 
the alinement posts should be lubricated previous to placing the jackets 
and effecting the adjustment. 
With the correct relationship between jackets and inlays retained tem- 
porarily with adhesive wax, all exposed surfaces of the inlays should 
be covered also with wax, as a means of keeping them clean. The rela- 
tionship now should be retained securely with soldering investment com- 
pound and retained in such manner as to insure a preservation of the 
relationship between inlay and jacket while soldering. This is accom- 
plished in the best manner by filling each jacket carefully with a thin mix 
of investment compound, first, and then slipping a small wire tack or a 
slab of slate, or carbon, well down into each jacket, and completing the 
investment as illustrated in Fig. 347. 
The use of a small wire tack is recommended only as a means of insur- 
ing the complete filling of the interior of the jacket with investment com- 
pound, and of holding it securely in the investment, after inlay and jacket 
are removed from the cast. 
Slabs trimmed from an ordinary slate pencil, heated previously, or 
from large leads from a lead pencil, and fitted closely into the jackets, 
also will answer the same purpose, but the complete filling of the interior 
of the jackets is imperative in all cases. REMOVABLE BRIDGEWORK 
383 
When invested in the manner indicated, each inlay and jacket should 
be detached from the plaster cast, and invested as illustrated in Fig. 348. 
When the investment has crystallized, the wax should be removed with 
boiling water, the parts fluxed properly and the case then placed over the 
flame and heated thoroughly before soldering. The size of the investment 
and the small area of metal surfaces exposed demands that the case be 
Fig. 348. 
heated to a high temperature before attempting soldering. Inlay and 
jacket then are united and all desired contour made with 22 karat solder. 
When the soldering has been completed, the inlays should be boiled 
in dilute hydrochloric acid until all refractory material is removed from 
the interiors of the jackets, and then finished to the point of polishing. 
The friction plates then should be lubricated and adjusted to position in 
the inlays; then they should be placed in position in the supporting teeth 
and the impression taken and the saddle made. 
This method of procedure involves a useful and simple technic which 
is applicable to any type of friction plate and jacket attachment and 
accuracy is insured because of obtaining parallelism and contour all at 
one time and upon one cast. 
Matrix Inlays. This same technic also may be followed without cast- 
ing. The shell inlay may be made by burnishing or swaging a matrix of 
pure gold, 36 gage, to the amalgam cast and then investing and slightly 
reinforcing the matrix with 22 karat solder. After reinforcing the matrix 
the same details of procedure are followed and the same results are ob- 
tainable, except that the adaptation of an inlay made with a matrix is not 
so accurate as is the adaptation of an inlay made by casting. 
Direct Method. The direct method may be used successfully in 
large inlays. Where this method of procedure may be preferable, the 384 
CROWN AND BRIDGEWORK 
wax pattern should be made in the usual manner. Accommodation for 
the retaining jacket then may be made in the wax pattern by the use of a 
round bur, or the suction carving instrument and a sharp carving blade. 
If the wax pattern is made of a hard casting wax, and is kept chilled, 
this procedure may be accomplished with ease and without danger of 
Fig. 349- 
distortion. When accommodation, even more than adequate has been 
made, the sprue-former then should be attached at a favorable point and 
the inlay invested and cast. When the casting has been made, ample 
accommodation for the jacket should be insured in finishing. 
The inlay or inlays then should be finished to the point of polishing, 
placed in position in the supporting teeth and the impression taken, the 
cast made, and the jackets alined and adjusted to proper relationship with 
the inlays and with each other, as described previously in connection with 
shell inlays, and in the same manner. 
“Movable-Removable” Bridgework. 
A type of construction designated as “movable-removable” bridgework 
has been suggested by Dr. H. E. S. Chayes. This type of removable 
bridgework embraces the application of retaining attachments of the 
vertical, bucco-lingual type, to inlays, or to artificial crowns, and a saddle 
formation of original design. (Fig. 349.) REMOVABLE BRIDGEWORK 
385 
The retaining attachments are made in a variety of sizes, adaptable 
to both anterior and posterior teeth, and the successful application of the 
attachments is insured by the use of a mechanically perfect paralleling 
instrument designed for the purpose, and called a “parallelometer.” (Fig. 
34i C.) 
Dowel Crowns. 
Vertical retaining attachments of the friction-plate and jacket type 
are applicable also to dowel crowns of any type. When used in con- 
nection with restorations of this type, the coping should be made in the 
usual manner and the facing selected, adapted and backed as described 
Fig. 350. 
Fig. 351 
previously. Coping and backing then should be invested and united, or 
tacked together with just enough solder to sustain the relationship. 
When the restoration is partially completed in this manner it should 
be placed in position on the supporting root, together with the other at- 
tachment, or attachments, and an impression taken in plaster. The cast 
then should be poured with soldering investment compound. When the 
cast has been obtained, the retaining jackets should be adjusted to the 
paralleling instrument and placed and alined as indicated for inlays. The 
desired relationship should be sustained with adhesive wax, the alinement 
posts detached, and the investment made, as already described. 
The precaution of using a small tack, or slab of carbon, as a retaining 
pin and of filling the interior of the jacket completely with the investment 
material must be observed carefully. 
The case then should be heated properly and the relationship between 
coping and jacket sustained permanently with 22 karat solder. All neces- 
sary contouring may be done at this time, also, with solder, or may be 
done subsequently by casting, though the latter procedure is rarely ever 
indicated. 386 
CROWN AND BRIDGEWORK 
A typical dowel crown restoration, with the jacket as a component part 
and showing the correct position of the jacket in its relation to the coping 
and facing, is illustrated in Fig. 350. 
The same method of procedure is applicable also to dowel-crown resto- 
rations made with a platinum coping and flat-back facing, and completed 
with baked porcelain. The basic requirements and the completed restora- 
tion with the jacket as a component part are illustrated in Fig. 351. 
Full Telescope Crowns. 
Vertical retaining attachments also are applicable to full telescope 
crown restorations. When used in this connection the band should be 
made, fitted and contoured in the usual manner. A slot, corresponding 
with the bucco-lingual dimensions of the jacket, then should be cut out 
upon the surface which is to receive and accommodate the jacket and into 
which the jacket should be fitted snugly. (Fig. 352 A.) 
A 
B 
c 
Fig. 352. 
Hard casting wax or temporary stopping then should be molded over 
the basal end of the root, completely filling the interior of the band level 
with its occlusal edge. The other attachment, or attachments, should be 
placed in position on their supporting teeth or roots and the bite taken in 
wax and the impression in plaster. The cast should be poured in hard 
soldering-investment compound. The bite then is adjusted to place and 
the cast mounted upon the articulator. When separated, the wax or 
temporary stopping in the band should be warmed and removed. The 
band then should be detached carefully from the cast in such manner as 
to permit of accurate replacement, and care should be exercised to avoid 
defacing the reproduction of the basal end of the root. When detached, 
the band should be cleaned in the acid bath and replaced accurately upon 
the cast. 
The retaining jacket then should be alined properly and placed just 
free of the opposing teeth and its relationship with the band sustained 
with adhesive wax. When the alinement post has been removed, band 
and jacket should be detached from the cast and invested. In investing, 
the jacket should be filled completely with investment compound and the REMOVABLE BRIDGEWORK 
387 
head of a retaining tack, or a slab of slate, or carbon, slipped down to 
place, as indicated previously. Just enough investment compound to fill 
the interior of the band and to hold the retaining tack or slab, and the 
retaining jacket securely should be used. When this has crystallized, the 
adhesive wax should be removed with boiling water and the surfaces of 
jacket and band exposed freely. 
The case then should be heated properly and the jacket attached to 
the band with 22 karat solder. (Fig. 352 B.) When the soldering has 
been completed, band and jacket should be cleaned in the acid bath, re- 
placed upon the cast and the occlusal surface restoration formed in casting 
wax, then invested and cast. In investing, it is necessary to observe that 
the jacket is filled completely with investment compound. The completed 
restoration is illustrated in Fig. 352 C. 
While vertical retaining attachments of this type may be used suc- 
cessfully in combination with full telescope crowns in this manner, they 
offer no special advantages over a well adapted clasp, especially if the 
telescope crown is constructed so as to accommodate the clasp without 
undue enlargement of the circumferential dimensions. 
Application of Split-Post and Tube Attachments 
Split-post and tube attachments are useful retaining devices. They 
are indicated in two classes of cases: First, in cases where the natural 
crown has been sacrificed previously, or must be sacrificed, to the gingival 
line; and second, in cases of assembled abutments where extensive restora- 
tion of lost tissue is demanded. 
As applied to the roots of teeth, split-post and tube attachments are 
used in combination with dowel-crown restorations, and are indicated only 
in cases where the dimensions of the root are favorable, as stated pre- 
viously. 
In the construction of dowel crowns in which a split-post and tube 
are to be used as a retaining agency, a coping which includes a full or 
partial band should be made and adapted in the usual manner, except 
that the tube instead of the split-post is attached to the floor of the coping. 
Before attaching the tube to the floor of the coping permanently by 
soldering, proper alinement and parallelism with the other attachment or 
attachments must be secured. 
Accurate parallelism between the supporting root, the tube and the 
coping, and the other attachment or attachments used, is difficult and 
exacting, but is possible, provided that a properly adapted paralleling in- 
strument is used, and may be obtained by observing the following method 
of procedure: 388 
CROWN AND BRIDGEWORK 
When the coping has been completed, the canal should be enlarged to 
receive and accommodate the tube freely. It should be enlarged to the 
fullest extent possible without weakening the root unnecessarily. The 
floor of the coping then should be perforated immediately over the center 
of the enlarged canal. 
As a means of facilitating soldering and of insuring strength in the 
union of the coping and tube subsequently, care must be exercised in ob- 
Fig. 353- 
Fig. 354- 
serving that the perforation through the floor is not larger in diameter 
than the diameter of the tube. Each tube then should be placed in posi- 
tion in its canal, and the terminals of the paralleling instrument lubri- 
cated with vaseline and introduced into the tubes to the full depth. 
With both tubes thus alined and held in position, the impression should 
be taken in plaster. Tubes and copings, together with the paralleling 
instrument, will be removed with the impression, and it must be observed 
that they are in their proper relation. (Fig. 353.) 
The cast then should be made of soldering investment compound. 
When the cast has been obtained, and tbe terminals of the paralleling 
instrument detached, carbon points, made by trimming down an ordinary REMOVABLE BRIDGEWORK 
389 
lead pencil, should be fitted closely and introduced into the tubes to their 
full depth, allowing some surplus to project. 
Parallelism between tubes and copings is then made permanent by 
soldering directly upon the cast. When the relationship between tubes 
and copings has been made permanent by soldering, the surplus ends of 
the tubes should be cut away with a thin-edge stone until nearly flush with 
Fig. 355- 
Fig. 356, 
the floor of the coping. The completed coping which is to be attached to 
the supporting tooth is illustrated in Fig. 354. 
This basic coping then is placed in position upon the root and a dowel- 
crown restoration embracing a partial telescoping band, together with the 
split-post as a dowel, is made in the usual manner as a single unit, and 
in accordance with the requirements of the case. (Fig. 355.) 
Application of Telescoping Crown Attachments. 
As applied to molar teeth telescoping crowns are one of the most useful 
retaining attachments for removable bridgework. This type of attach- 
ment consists of two parts, a basic coping, and a telescoping coping, both 
of which must be made for the individual case. It is used extensively 
by Dr. F. A. Peeso, and is constructed as follows: When the supporting 390 
CROWN AND BRIDGEWORK 
tooth has been prepared as indicated in Fig. 356 A, the measurement is 
taken, and a band is made of 28 gage, 22 karat, or coin gold. In cutting 
the band, the edges should be cut at an angle which will make the circum- 
ference of the occlusal edge smaller than the gingival edge. (Fig. 356 B.) 
The band should then be made in circular form and soldered, using a 
minimum of solder. It should then be trimmed and fitted to the support- 
ing tooth. When fitted to meet the requirements, the occlusal edge should 
be adapted closely to the axial walls, and trimmed flush with the occlusal 
surface. A floor of the same karat and thickness of gold should be at- 
tached with a minimum of solder. (Fig. 356 C.) The surplus should 
be trimmed away, and the basic coping thus formed, finished and fitted to 
position on the tooth. 
When adapted satisfactorily, the basic coping should be removed and 
its interior painted with a thin coating of melted wax. A piece of heavy 
paper, cut previously to the size desired, should now be wrapped around 
the coping in such manner as to form a matrix for a handle, and should 
be tied with a ligature. A low fusing, fusible alloy should then be melted 
and poured into the coping and paper matrix. Painting the interior of 
the coping with melted wax will prevent contamination with the fusible 
alloy, and facilitate the removal of the coping subsequently. 
When the fusible alloy has cooled, the paper matrix should be removed. 
The basic coping then presents as shown in Fig. 356 D. A measurement 
of the gingival edge should now be taken, and the telescoping band made 
and fitted in exactly the same manner as was followed previously in making 
the basic band. When fitted to place over the basic coping, the occlusal 
edge should be flush with this edge of the coping, but the gingival edge 
should be a trifle shorter, as illustrated in Fig. 356, E. A floor now 
should be attached, and the telescoping coping completed. (Fig. 
356 F.) 
The basic coping now should be warmed slightly over a flame and re- 
moved from the fusible alloy. Both basic and telescoping copings should 
then be placed in position on the supporting tooth, a bite and impression 
taken, and the cast made and mounted upon an articulator. The restoration 
of contour should be made with casting wax, by applying it to the basic 
coping either in melted or in plastic form. When the contour required 
and the carving desired have been completed, the wax restoration then 
should be teased loose, and removed from the telescoping coping. (Fig. 
356 G.) 
The sprue-former should now be adjusted to position and the wax 
restoration invested and cast. When the casting has been made and 
finished, it should be attached to the telescoping coping with a small bit REMOVABLE BRIDGEWORK 
391 
of solder applied around the gingival edge. The completed telescoping 
restoration is illustrated in Fig. 356 H. 
Fig. 357- 
For the reason that better results and greater accuracy are obtainable 
by making the casting separately and attaching it with solder subse- 
quently, no effort should be made to cast the restoration directly to the 
telescoping coping. 
Assembled Abutments. 
The application of split-post and tube attachments is not limited to 
the roots of teeth alone, but may be made successfully in many classes 
of cases. It is a particularly useful type of retaining attachment in cases 392 
CROWN AND BRIDGEWORK 
of assembled abutments, and in cases demanding extensive or abnormal 
restoration. 
The assemblage of abutment teeth consists in obtaining attachment to 
two or more teeth and in uniting these attachments with a basic structure 
which rests upon the mucosa and which is cemented to place as a single 
unit. The replacement of missing teeth and the restoration of lost tissue 
Fig. 358. 
then is made in the form of a removable structure which is retained 
in position by means of the basic structure with which the abutments have 
been assembled. 
Indications. The assemblage of abutment teeth is a useful method 
of procedure in some cases, but it is a procedure which does not subscribe 
to the highest requirements of sanitation. It is indicated in two general 
classes of cases only : 
First: In cases where one or the other or all of the teeth which it REMOVABLE BRIDGEWORK 
393 
may be desirable to use as abutments have become loosened in their at- 
tachment to the investing tissues, with no absolute pathological condition 
existing, and where their retention is desirable. By means of assembling 
Fig. 359. 
them one with the other, health may be promoted and many years of use- 
fulness may be obtained by stabilizing them, or by placing them in a 
state of partial rest. 394 
CROWN AND BRIDGEWORK 
The somewhat prevalent opinion to the effect that if a tooth is suffi- 
ciently loose to require stabilizing, it is sufficiently loose to be lost, is not 
confirmed by clinical observation and is not entirely rational, unless an 
extreme pathological condition exists. 
A typical case of assembled abutments, showing the application of the 
Roach attachment, used in connection with inlays having a partial periph- 
eral band, and where considerable tissue restorations is required, is illus- 
trated in Fig. 357. 
Second: In cases demanding extensive restoration of lost tissue, and 
where it is not advisable, or may not be possible to have a fixture of any 
type rest upon the edentulous tissue. 
Fig. 360. 
A typical case of this class, involving the assemblage of the abutments 
and the successful application of a single split-post and tube attachment 
and an extensive restoration, is illustrated in Fig. 358 A. 
In many cases of cleft palate, or of extensive surgical procedure, the 
abutment teeth often may be good, sound and free from pathological 
lesions, and yet not firm. In such cases several years of usefulness may 
be obtained from their assemblage and partial fixation, even in the simplest 
manner. 
In this particular case, simple, open-face crowns, made of 28 gage 
platinum, were adapted to the abutments and assembled with a round, 
iridio-platinum wire, 14 gage. A split-post was attached securely to the 
center of the assembling wire by soldering. (Fig. 358 B.) Retaining 
plates, made of 28 gage, 22 karat gold plate, were attached to the tube 
labially and lingually and trimmed to follow the outline of the assembled REMOVABLE BRIDGEWORK 
395 
wire. (Fig. 358 C.) These retaining plates serve the purpose of afford- 
ing attachment of the tube to vulcanite (Fig. 358 D), of which the resto- 
ration was made. 
Another more extensive case, typically illustrative, and indicating the 
usefulness of assembled abutments and of split-post and tube attachments, 
and demanding an extensive restoration, is illustrated in Fig. 359 A. In 
this case the restoration involved the replacement of a segment of the 
mandible lost through accident. The assembling bar, designed by Dr. 
Calvin S. Case, ingeniously sustained the normal relation of the mandibular 
fragments and yet permitted a rotary movement upon the right side and 
a hinge movement upon the left side. It was made of round iridio- 
platinum wire, 12 gage, to the center of which two split-posts were 
paralleled and soldered. (Fig. 359 B.) The tubes then were united 
and a removable fixture built around them in vulcanite. (Fig. 359 C.) 
Application of Horizontal Attachments. 
As indicated previously, horizontal attachments embrace that type of 
attachment which consists of an interlocking friction bar and jacket in 
which the greatest area of frictional contact is mesio-distal and in a line 
horizontal with the long axis of the supporting tooth. 
Indications. Attachments of this type are applicable to inlays, dowel 
crowns or full telescope crown restorations and to anterior, as well as 
posterior teeth, but afford no especially advantageous features. 
Indeed, the depth to which horizontal attachments must be imbedded 
in the supporting teeth in order to insure adequate strength and stability, 
usually demands pulp destruction; and when pulp destruction is required, 
the rational application of any type of retaining attachment is limited. 
The general indications for the use of attachments of this type, therefore, 
embrace only teeth which are already pulpless. 
Attachments of this type are made for the individual case and the 
design and size of the friction bar vary accordingly. Usually a split-bar 
is used and is made by bending over upon itself a piece of flattened iridio- 
platinum wire, of a size and shape adapted to the requirements of the 
case, and then shaping and forming it as desired. To preclude mesio- 
distal movement, the free end of the friction bar is always bent in such 
manner as to interlock in its jacket. 
An open jacket then is made to fit three surfaces of the friction bar, 
using thin platinum or pure gold, about 36 gage, for the purpose. As 
in the case of split-post and tube attachments, the split-bar permits of 
tightening. 396 
CROWN AND BRIDGEWORK 
The placing, the alinement and the bucco-lingual paralleling of at- 
tachments of this type, whether used in connection with inlays, or dowel, 
or full telescope-crown restorations, are made upon the cast then with 
an observation of all precautions and careful technic indicated previously 
both for vertical and split-post and tube attachments. This type of re- 
taining attachment is used extensively by Dr. C. F. Ash. A typical appli- 
cation is illustrated in Fig. 360. 
Fig. 361 A. 
Fig. 361 B. 
Combining Retaining Attachments of Different Types, 
The use of two different types of attachments is indicated frequently 
if the selection is made with discrimination and if the particular types 
best adapted to the case at hand are wisely selected. Indeed, the use of 
two different types is often advantageous, insuring greater stability than 
would obtain from the use of two attachments of the same type. 
Indications. As an illustration : A cuspid root and a cavity involving 
the occluso-mesial surfaces of a first molar, with the bicuspids missing, REMOVABLE BRIDGEWORK 
397 
would provide indications typical for the use of a split-post and tube 
attachment upon the cuspid root, and a horizontal attachment resting in a 
gold inlay in the molar, as illustrated in Fig. 361 A. 
In the use of attachments of different types in the same fixture, how- 
ever, the requirements of adaptation and of mutual j. arallelism do not 
differ essentially and must be met with the same precautions and with the 
same careful technic that would be utilized in the employment of attach- 
ments of the same type, as indicated previously. (Fig. 361 B.) 
Construction of Saddles. 
The saddle is an important component part of removable bridgework. 
Its function is to sustain the relationship of the retaining attachments, 
stabilize the fixture, support the pontics, and afford opportunity for the 
artificial restoration of lost tissue. 
The first requirement incident to the construction of the saddle is an 
accurate impression. The second is an accurate cast. When the retain- 
ing attachments have been completed as single units, all refractory mate- 
rials should be removed from the interiors of the jackets and the friction 
plate, tube, or bar, lubricated with oil or vaseline and adjusted to its proper 
position in each jacket. The completed attachments then should be placed 
in position in the supporting abutments and an impression taken in plaster. 
When the impression has been obtained, the retaining attachments 
should be removed from the abutments and placed accurately in the im- 
pression. The latter then should be varnished and poured, using a good 
grade of cast plaster. Plaster is used for the reason that it affords 
smoother and more perfect surface outlines. 
When the cast, with the attachments in position, has been obtained, 
the saddle should be designed and the outlines traced with an indelible 
pencil. The surface of the cast at this point then should be depressed 
slightly by scraping. 
The design of the saddle is an important feature. The requirements, 
as previously indicated, should be observed carefully. 
In small, unilateral fixtures the general design, originally suggested 
by Dr. H. E. S. Chayes, meets the physiological and mechanical require- 
ments favorably and offers a minimum of mechanical incumbrance. 
When restoration is demanded, the size of the saddle must be increased 
proportionately; and in bilateral maxillary fixtures, the outline should 
be fitted in and around the rugae in such manner as to minimize mechanical 
incumbrance. When the design has been determined and outlined on 
the cast, the saddle may be made either by casting or by making dies and 
swaging. 398 
CROWN AND BRIDGEWORK 
Casting. The casting process offers the most simple, expedient and 
accurate means of making the saddle. Saddles made by casting are 
stronger. 
In making saddles by the casting method, the cast first should be lubri- 
cated with thin oil. Thin sheet casting wax, which is prepared especially 
for this purpose, then should be made plastic by dipping in warm water 
and molded over the cast, using pledgets of cotton, also dipped in warm 
water, to conform it to the surface of the cast closely. The wax pattern 
then should be trimmed to follow the outlines indicated on the cast, and 
to fit the exposed surfaces of the friction plate, tube, or bar in such manner 
as to facilitate their attachment to the finished saddle, subsequently, by 
soldering. 
Pontics 
The type of pontics to be used in the case must be considered at this 
time. In small fixtures involving one, two or three pontics, where but 
little, if any, restoration of lost tissue is demanded, the use of some type 
Fig. 362. 
of all-porcelain pontic affords the most esthetic and sanitary results. In 
the use of pontics of this type, the bite must be taken previous to taking 
the impression and the casts must be mounted upon the articulator. 
All-Porcelain Pontics. Several types of all-porcelain pontics are 
used. These include the “Trubridge’’ (Fig. 362) and Ash and Sons all- 
porcelain tube teeth, the Goslee tooth, and diatoric bicuspids and molars. 
Wherever tube teetb may be used as pontics, their use affords the 
most typical reproduction of natural tooth form; hence the most esthetic 
results. In their use the selection as to size, color and type should be 
made with care. 
When the selection has been made and the requirements of adaptation 
and of occlusion have been met, the central retaining hole should be filled 
with plaster; or this may be done before grinding. The basal end of each 
pontic then should be lubricated with thin oil, after which it should be 
placed in position on the wax pattern and its relationship sustained with REMOVABLE BRIDGEWORK 
399 
Fig. 363- 
melted wax. When all pontics have been assembled in this manner and 
when the assemblage meets all requirements, the basal end of each pontic 400 
CROWN AND BRIDGEWORK 
should be housed nicely with melted casting wax and the pattern reen- 
forced and contoured, as desired. 
The pontics then should be detached carefully and the sprue-former 
attached securely at a point relatively near the center of the pattern. 
(Fig. 363 A.) The entire surface of the saddle then should be wiped 
clean with acetone, using a small brush or pledget of cotton, and then 
covered carefully with a thin layer of casting investment compound. This 
should be painted over the surface with a small brush as a means of avoid- 
Fig. 364 A. 
ing confined air. Any confined air would result in imperfections in the 
casting. This layer of investment compound should be sufficiently heavy 
to insure a preservation of the shape and form of the wax pattern, and 
the sprue-fonner, of course, must be left exposed. (Fig. 363 B.) 
The partially invested pattern should be detached carefully from the 
cast, submerged in cold water, placed in the base of the flask, the invest- 
ment completed, burned out, and the casting made. (Fig. 363 C.) 
The same method of procedure should be followed in the use of dia- 
toric, Goslee, or similar types of porcelain teeth as pontics, except that 
in the use of teeth of this type, each pontic should be backed separately 
with pure gold, 36 gage, previous to final adjustment to the wax pattern. 
This precaution is necessary at all times, and in all cases, as a means of 
securing the relationship of the retaining post and of insuring accuracy 
of adaptation in the casting. 
When backings for pontics of this type have been adapted closely and 
trimmed to the outlines desired, a perforation should be made immediately 
over the retaining hole and a retaining post of proper diameter fitted, 
allowing some slight surplus to project beyond the surface of the backing. 
The relationship between backing and retaining post should be secured 
with adhesive wax and the two then removed from the pontic, invested, 
and united with solder. Any unnecessary surplus of retaining post then REMOVABLE BRIDGEWORK 
401 
should be cut off, allowing just sufficient surplus to insure strength to 
remain, as illustrated previously in Fig. 300 A. 
When each politic has been backed in this manner, all should be placed 
in position on the wax pattern, assembled properly, and the necessary 
contouring and reenforcement of the pattern made with casting wax. The 
politics then should be removed and the investment and casting made as 
indicated previously for tube teeth, and in the same manner. 
Fig. 364 C. 
Artificial Restoration of Lost Tissue, 
Where the artificial restoration of lost tissue is demanded to any 
appreciable extent, either porcelain or vulcanite must be used. 
Since it is not feasible and usually not possible to subject retaining 
attachments to the heat required to fuse porcelain compounds, if all-porce- 
lain restorations are demanded, they must be made separately and united 
subsequently. Restorations made in vulcanite, however, usually will 
subscribe to all requirements and answer all purposes. 
In making saddles where vulcanite restoration is demanded, the saddle 
should cover a somewhat greater area of the mucosa and the exact design 
and outlines should be determined and indicated on the cast. 402 
CROWN AND BRIDGEWORK 
The wax pattern should be formed on the cast and in the same manner, 
but should include thicker and more rounding edges and should provide 
for a secure and adequate mechanical attachment of the vulcanite, all of 
which may be provided for in the wax. The sprue-former should be 
attached (Fig. 364 A), and the investment and casting made. (Fig. 
364 B.) Larger castings of this type are illustrated'in Fig. 364 C. 
Swaging. 
In making the saddle the swaging process ofifers no advantages what- 
ever over casting, and while good results are obtainable by swaging, this 
method of procedure is indicated only in cases where the size of the 
saddle may make casting difficult, or in the absence of facilities for casting. 
In making dies for swaging saddles, low-fusing alloys may be used 
for small structures, but when of large size the best results will obtain 
from the use of a die made of Babbitt metal, or zinc, with a counter-die 
of tin and lead. 
In swaging, the surfaces of the dies should be oiled and 22 karat, 28 
gage, gold plate should be used. In small unilateral structures one thick- 
ness usually will be sufficient, but in larger, or in bilateral structures, re- 
enforcement, adequate to the requirements of strength must be made. 
Such reenforcement should be'obtained by swaging a second saddle of 30 
or 32 gage, somewhat smaller in outline and uniting the two with 22 karat 
or 20 karat solder, or by the use of clasp metal, or wire, adapted closely 
and attached with solder. 
When the saddle has been made by either method, and made in accord- 
ance with the requirements, it should be boiled in the acid bath and finished. 
It is ready then for the attachment of the retaining agencies by soldering. 
Assembling. 
The greatest possible care must be exercised in assembling the saddle 
and the retaining agencies. When the saddle has been completed, the 
retaining attachments should be placed in position on the supporting teeth 
and the final adaptation and adjustment of the saddle to the retaining at- 
tachments and to the mucosa made. An impression which will transfer 
this relationship to the laboratory accurately then should be taken in 
plaster. 
The saddle should be forced and held in its relationship with the 
mucosa gently, but firmly, previous to and at the time of taking the im- 
pression. A close adaptation of the saddle to the mucosa in the finished 
structure would not obtain if the assemblage of the saddle and the attach- REMOVABLE BRIDGEWORK 
403 
ments were to be made directly upon the original cast upon which the 
saddle was made. Nor will it obtain unless this feature of gentle but 
firm pressure is observed at the time of taking the impression. 
In small structures the best results are to be had by holding the saddle 
firmly with the fingers and placing just a small quantity of plaster over 
and around each attachment separately, and removing and soldering each 
Fig. 365 B. 
Fig. 365 A. 
attachment separately. In this procedure the saddle is held firmly with 
the finger, and the plaster is carried to place on the end of a spatula and 
plastered over and around the saddle and the attachment, using only 
enough to insure strength. The saddle and the attachment usually will 
be removed with the impression. 
It is rarely ever safe to attempt to solder the saddle to the friction 
plate, post or bar while in position in the jacket, but is always better 
and safer to separate the retaining attachment, and then carefully replace 
the friction plate, post or bar in the impression. If, for any reason, the 
parts should be reversed, the same precaution applies. The impression 
then should be varnished and poured, using an exceedingly hard soldering- 
investment compound. Care should be exercised in separating and, when 
separated, all exposed surfaces of saddle and retaining attachment should 
be cleaned thoroughly and fluxed properly. The case then should be 
heated and the parts united with 22 karat or 20 karat solder. 404 
CROWN AND BRIDGEWORK 
The same procedure then should be followed in obtaining the relation- 
ship and in effecting the assemblage of the remaining attachment or 
attachments. While it is safer usually to effect the assemblage of each re- 
taining attachment to the saddle separately and in this manner, it is not 
an imperative method of procedure. Other means of applying moderate 
pressure upon the saddle may be observed and the relationship between 
the saddle and both or all retaining attachments may be obtained with 
a single impression. 
Fig. 366. 
In small structures, adequate pressure upon the saddle may be secured 
by the use of a wedge made from an orangewood stick and base-plate wax, 
or temporary stopping, as indicated previously in Fig. 330. Or, in larger 
structures, mandibular pressure often may be used successfully and to 
advantage. 
In the application of mandibular pressure, a stick of orangewood 
should be cut to a length which will permit one end to rest firmly upon 
the saddle, relatively near its center, and the other end to rest upon the REMOVABLE BR1DGEWORK 
405 
opposing teeth, as illustrated in Fig. 365 A. If the opposing teeth are 
absent, one end may be cushioned with impression compound so as to rest 
upon the mucosa and permit of pressure without discomfort, as illustrated 
in big. 365 B. With the retaining attachments and saddle in position, 
the impression may be taken in a specially prepared tray (Fig. 366) with 
gentle, but firm, mandibular pressure upon the saddle by means of the 
orangewood stick. In the insertion of the impression, the slot in the tray 
will straddle the orangewood stick and permit the proper placement of 
the impression. 
When the impression has been obtained by either method of procedure, 
the retaining attachments should be removed and detached as indicated 
previously and for the same reasons. The friction plate, post or bar then 
should be replaced, the impression varnished and the cast made as 
indicated. 
When the assemblage of all retaining attachments has been completed, 
the fixture should be cleaned in the acid bath and fitted to position upon the 
supporting abutments. When the adjustment is satisfactory, the pontics 
should be attached. 
Attachment of Pontics. 
When tube teeth have been used as pontics, the plaster with which 
the retaining holes were filled previously should be removed. Each politic 
then should be placed in position on the structure and the retaining post 
adjusted and attached to the saddle. Iridio-platinum or clasp-metal wire 
of relatively the same diameter as the diameter of the retaining hole is 
used for the retaining post. 
In effecting the adjustment and attachment of the retaining post to 
the saddle, a length of wire somewhat longer than necessary should be 
cut. One end should be painted with lamp-black mixed with glycerin. 
With the pontic in its proper position, this end of the post should be intro- 
duced into the retaining hole and passed through the pontic until in con- 
tact with the saddle. The lamp-black will leave an imprint. 
The pontic now should be removed and a hole of the diameter of the 
retaining post then drilled through the saddle at this point. The pontic 
then should be replaced in position on the saddle and the retaining post 
inserted and forced through pontic and saddle until its surplus end projects 
through the saddle. The relationship between the saddle and the retaining 
post then should be sustained securely with adhesive wax. 
When the retaining post for each pontic has been attached to the saddle 
in this manner, the pontics should be removed and the structure invested. 406 
CROWN AND BRIDGEWORK 
The investment should be made in such manner as to leave exposed only 
that surface of the saddle which rests upon the mucosa. 
When the investment has crystallized, the adhesive wax used to sustain 
the retaining posts should be removed with boiling water, each joint fluxed 
and the case heated and the retaining posts attached to the saddle with a 
small bit of 22 karat or 20 karat solder. After soldering, the surplus 
end of the retaining posts should be cut away and the fixture cleaned in 
the acid bath and then finished and polished, after which the pontics should 
be cemented to place. 
When the retaining posts constitute a part of the casting, as indicated 
in the use of all other types of all-porcelain pontics, as soon as the as- 
semblage of the retaining attachments and the saddle has been completed 
and the structure finished and polished, the pontics should be cemented 
to place. 
Use of Replaceable Facings as Pontics. 
When replaceable facings are to be used as pontics, as soon as the 
retaining attachments have been assembled to the saddle and the relation- 
ship of the structure and its attachments to the supporting abutments 
has been proved correct, structure and attachments should be placed in 
position on the abutments, the bite taken in wax and the impression in 
plaster. 
The abutment part of the attachments should be detached and placed 
aside and the impression then varnished and filled with high-grade in- 
vestment compound. The bite should be adjusted and the case mounted 
upon the articulator. 
Facings and backings now should be selected and adapted to the re- 
quirements. The relationship between the backings and the saddle then 
should be sustained with adhesive wax and the facings removed. Before 
sustaining the relationship it is well to make sure that each facing may be 
detached easily from its backing. When the desired relationship has beenl 
sustained securely and all facings removed, the cast then should be de- 
tached from the articulator, submerged in cold water, and the relationship 
secured with investment compound, using only enough to cover and pro- 
tect the backings and to insure strength. When the investment has 
crystallized, the wax should be removed with boiling water, the surfaces 
of the saddle and backings fluxed properly and the case then heated and 
the assemblage and contour made with 20 karat solder. The same pro- 
cedure applies also to the use of posterior pontics of the replaceable 
type. REMOVABLE BRIDGEWORK 
407 
Vulcanite Restoration. 
In structures demanding restoration of lost tissue, and where the 
saddle has been made with provisions for the use of vulcanite, the struc- 
ture should be adjusted to position on the supporting abutments when 
the assemblage of the retaining attachments and the saddle has been made 
in the manner indicated. The bite then should be taken in base-plate wax 
and the impression in plaster. 
When the cast has been obtained and mounted upon the articulator, 
vulcanite pontics should be selected and adapted to the requirements. 
The required restoration then should be made with wax, the case flasked, 
packed, vulcanized, and finished as usual. 
Fig. 367. 
Vulcanite Saddles. When, for economical or other reasons, the 
entire saddle is to be made of vulcanite, accurate and reliable results will 
not be obtained unless the retaining attachments are assembled previously; 
and assembled in such manner as to insure a preservation of their rela- 
tionship during the procedures incident to flashing, packing and vul- 
canizing. 
Where the structure is to be made entirely in vulcanite, the retaining 
attachments should be placed in position in the abutment teeth, the im- 
pression taken in plaster and the cast made in investment compound in 
the manner indicated. 
The relationship between the attachments then should be sustained by 
uniting them with clasp-metal wire of a size which will insure strength 
in their assemblage, independently of the vulcanite. The assembling wire 
should be adapted in such manner as to be completely imbedded in the 
vulcanite, and yet not interfere with the placement of the pontics. Round 
clasp-metal wire, 14 gage to 16 gage is used for this purpose. (Fig. 367.) 
When the retaining attachments are assembled thus, they should be 
placed in position on the abutment teeth and the bite taken in pink base- 
plate wax and the impression taken in plaster. The cast then should be 
made in plaster and mounted upon the articulator. The pontics now 408 
CROWN AND BRIDGEWORK 
should he selected and adapted and the saddle and restoration required 
made with wax. The case then should be completed in the usual manner, 
as described for vulcanite work. 
Cementing Retaining Attachments to Abutments. 
In all types of removable bridgework, that part of the retaining agency 
which is to be attached permanently to the supporting natural tooth 
should not be cemented to place finally until both, or all, of the retaining 
attachments have been assembled securely, and their correct relationship 
proved. 
Irrespective of the fact that parallelism was obtained in seating the 
retaining agencies in their attachments to the supporting abutment teeth 
originally, it is advantageous to defer the final mounting until after the 
assemblage of the basic structure. As soon as the retaining attachments 
have been assembled with the saddle, or united with an assembling wire, 
however, and the correct relationship proved, the attachments may be 
cemented to the abutments. 
This procedure may be followed with the greatest degree of accuracy 
and certainty by assembling the structure and all of its attachments first, 
and then cementing it as a single unit. When cemented, the removable 
structure should not be disturbed until ample time for complete crystalliza- 
tion of the cement has been allowed. Any danger of uniting the retaining 
agencies may be overcome by attaching them with melted wax previous 
to cementing. 
When the attachments are cemented previous to the attachment of the 
pontics with vulcanite, the fixture should be removed and replaced several 
times before the bite and impression are taken. 
Summary. 
All types of retaining agencies, except clasps, consist of two parts, 
one of which engages the other closely. One part is attached to the sup- 
porting abutment in a fixed manner. The other is attached to the remov- 
able structure. Their relationship is sustained by frictional contact be- 
tween the closely interrelated telescoping surfaces. 
Manufactured attachments are made in steel dies and are perfect 
mechanically. Mechanically perfect attachments are essential to the suc- 
cessful application of removable structure. Therefore, in the use of re- 
taining agencies of any type, every precaution to insure preservation of 
close interrelationship between the telescoping surfaces must be observed 
at all times. REMOVABLE BRIDGEWORK 
409 
The friction plate, post or bar never must be bent, indented, nor de- 
faced in any manner and the interiors of the jackets and tubes must be 
kept clean and free from refractory materials. Throughout the construc- 
tion of removable bridgework, therefore, the telescoping surfaces of both 
parts of retaining agencies must be protected. 
Fig. 368. 
The interiors of jackets and tubes may be kept free from solder only 
by filling them carefully before soldering. A slate pencil heated to a 
cherry-red and trimmed to fit; graphite, from a lead pencil, trimmed to 
fit; crocus, cement, whiting, plaster, or any heat-withstanding oxidizing 
agent, which is removed easily by boiling in acid, will answer this purpose. 
No field of dental efifort offers so many diversified methods nor de- 
mands more exacting operative procedure, nor more exacting mechanical 
and technical training than does the successful application and construc- 
tion of removable bridgework. 
All methods of procedure and all methods of attachment have a field 
of usefulness. None are applicable universally. None may be used to 
the exclusion of all others. 
Precautions. 
In the replacement of but one or two missing teeth by means of re- 
movable bridgework, exceedingly small structures should be avoided. An 
element of danger from swallowing small structures enters into their in- 
sertion, and while such a mishap is unusual, it is nevertheless possible, as 
illustrated in Fig. 368. Principles and Technics of Clasp 
Denture Construction 
CHAPTER XVIII. 
CLASP DENTURES. 
Clasps were the original retaining agencies, and clasp dentures ante- 
dated all methods of mechanically retaining removable restorations in the 
replacement of missing teeth in partially edentulous cases. 
A clasp denture, therefore, is simply another and simpler form of 
removable bridgework, and when more than three or four teeth are to 
be replaced in a single structure, well designed and well made clasp 
dentures are still the most generally applicable, useful, efficient and 
economical method of procedure. 
The application of clasps as retaining agencies for partial restorations 
probably antedated the advent of vulcanite as a base, but since this time 
clasps of some type have been in general use, and quite as many types 
have been suggested and used as have been suggested and used as retain- 
ing agencies for removable bridgework. 
The primitive type of clasp was made by bending small round, or half 
round wire to partially encircle the crown of the supporting natural tooth, 
and then forming a loop for the purpose of affording attachment for 
vulcanite. (Fig. 369.) 
As an evidence that some injury to the natural crown of the supporting 
tooth followed the use of this simple form of clasp, as a result of abrasion, 
and that some effort to diminish or eliminate the devastating influence of 
abrasion must be made, the introduction of the Bonwill clasp followed. 
This type of clasp was made of heavy gold plate, and provided with an 
occlusal rest, and was undoubtedly the progenitor of modern clasps. 
(Fig. 370.) 
In the replacement of missing teeth in partial restorations clasps serve 
as retaining agencies by virtue of resilient arms which partially encircle 
and grasp the circumference of the crowns of the supporting natural teeth 
and are retained by frictional contact. 
410 CLASP DENTURES 
411 
Advantages. The use of clasps as retaining agencies affords three 
distinctively advantageous features: First, retention of the restoration 
without mutilation of the supporting tooth; second, simplicity of applica- 
tion and construction; third, economy. 
Retention. In all forms of partial denture restorations, efficiency 
and comfort are increased in proportion to the degree of fixation. But 
as the structure increases in size, in order that it may meet the demands 
of replacement and restoration, it must be removable. This is essential 
Fig. 369. 
Fig. 370. 
because of the requirements of sanitation. Hence, if natural tooth struc- 
ture and pulp vitality are to be conserved at all times, any method of 
obtaining fixation which will at the same time permit of removal and 
replacement without requiring immediate mutilation of the supporting 
tooth crown, has a wide range of application and usefulness. 
It is true that any type of clasp eventually will do more or less injury 
to the supporting natural crown, irrespective of however perfectly, or 
imperfectly, it may fit. Still, many years of usefulness as a retaining 
agent may be afforded before serious injury develops, while immediate 
injury in the form of more or less extensive mutilation is required in the 
application of all other types of retaining agencies now used. The 
application of clasps, therefore, is often the lesser evil for this reason. 
Simplicity. The simplicity of technic involved in the application and 
with which accuracy of adaptation may obtain, together with the less 
exacting demands of parallelism made possible by the proper formation 
of the resilient arms, cause clasps to be more generally and more suc- 
cessfully applicable in the hands of the greater number. And any 
method which involves a simplicity of technic, insuring successful appli- 
cation in the hands of the greatest number, is always a useful and valuable 
procedure. 
Economy. The successful application of some of the more complex 412 
CROWN AND BRIDGEWORK 
types of retaining agencies necessarily involves an expenditure of time 
which makes the cost of production prohibitive in many cases. 
The time required and the initial cost in the application of clasps are 
reduced to a minimum. This affords an economical advantage which 
places clasp fixtures within the reach of all. 
Indications. The use of clasps as retaining agencies in partial-denture 
restorations is indicated generally in the following classes of cases: 
First: When a removable type of fixation is preferable or necessary. 
Second: In all cases where any immediate mutilation of the crowns 
of supporting natural teeth is undesirable. 
Third: Wherever the number of missing teeth to be replaced greatly 
exceeds the number of abutment teeth. 
Fourth: When the distribution of the abutment teeth is unfavorable 
to the application of any other type of retaining agent. 
Fifth: When the shape and the inclination of the natural crowns 
of the abutment teeth are favorable to the adaptation and mechanical re- 
tention of the resilient arms of a clasp. 
Sixth: When normal stability of the abutment teeth does not obtain, 
and, hence, when the use of some simple form of retaining agent is 
demanded. 
Application. The successful application of clasps as retaining agencies 
will depend, primarily, upon the adaptation of the resilient arms to the 
circumference of the crowns of the supporting natural teeth. Hence, 
the shape and contour of the crowns of the natural teeth which are to 
support clasps must be favorable. 
Bicuspids and Molars. For this reason, successful application is 
limited chiefly to bicuspid and molar teeth, and when confined to the 
bicuspid and molar teeth, success and usefulness are usually insured. 
And whenever clasps may be adapted to and used in connection with 
full telescope-crown restorations (a particularly ideal application), the 
maximum of usefulness and of permanency obtains and is insured. 
Cuspids. Clasps may be adapted to the crowns of cuspid teeth and 
often may serve successfully as retaining attachments when applied 
thereto; but the natural shape and form of the cuspid teeth is not favor- 
able, primarily, to the secure retention of clasps. Hence, when the appli- 
cation to cuspid teeth must be made, too much must not be expected. 
Incisors. The natural formation of the crowns of the incisor teeth 
is still more unfavorable to the successful application of clasps as retain- CLASP DENTURES 
413 
ing agents. The usefulness of clasps as applied to the incisor teeth, there- 
fore, is negative and the application is contraindicated in all cases. 
Requirements. 
In the successful application of clasps as retaining agencies, they must 
subscribe, primarily, and in a general way, to the following requirements: 
First: A clasp must consist of a rigid center and two resilient arms. 
Fig. 371. 
Second: It must be made of an alloy which possesses both tensile 
strength and resiliency. 
Third: In order that its relationship may be retained firmly by fric- 
tional contact, it must encircle at least three angles of the circumference 
of the crown of the supporting natural tooth. (Fig. 371.) 
Fourth: Its width should not be greater than necessary to insure 
sufficient surface contact to sustain relationship. 
Fifth: It should be well adapted to the surfaces of the natural crown 
with which it comes in contact. 
Sixth: It should be provided with an occlusal or lingual rest which 
will sustain its relationship, diminish abrasion, and prevent any subsequent 
settlement of the structure which it supports. 
Seventh: It should not encroach upon the gingival tissues, nor inter- 
fere with occlusion. 
Eighth: It should not displace the supporting abutments, nor be 
retained by binding one against another. 414 
CROWN AND BRIDGEWORK 
Ninth: It should be attached to the structure securely, but not neces- 
sarily rigidly, at a point relatively near its center. And in order that 
resiliency may be effective, both arms must be free from contact with 
the structure itself. 
Tenth: All edges should be rounded and smooth, and all surfaces well 
polished in order that no irritation may be offered. 
Fig. 372 A. 
Fig. 372 B. 
Efficiency of Clasps as Retaining Agencies 
The efficiency of clasps, as retaining agencies, will depend entirely 
upon the relationship which they bear to the crowns of the supporting 
teeth. 
In order that a clasp may grasp the supporting tooth crown and may 
be retained in its relationship thereto, the central part, which is made 
rigid subsequently by its attachment to the structure, must never be ex- 
tended gingivally beyond the height of contour of the natural crown; but CLASP DENTURES 
415 
its two resilient arms must completely engage and extend gingivally 
slightly beyond the greatest circumference. 
Height of Contour. An analytical study of tooth surfaces will dis- 
close that a definite conformation has been provided by Nature, with 
the object of affording a protection to the environing soft tissues. A 
view from the occlusal surfaces of all teeth discloses a slanting plane 
leading away from the gingiva. As soon as this plane has been extended 
far enough to overhang the gingiva, the plane rapidly turns or slants back, 
Fig. 373- 
rootward, or towards the gingiva. The first or upper plane is long, 
and the second or receding plane is quite short. Just at the juncture of 
these two planes is what is known as the “height of contour.” We cannot 
speak of this as the “greatest circumference” of the tooth, because it is 
not a straight line, but follows accurately the festoon of the gingiva. 
It is imperative that the height of contour of the natural tooth crown 
should be located on the cast before designing the outlines of the clasp 
(Fig. 372 A), and that all abnormal inclinations and variations should be 
observed closely. Efficiency will depend more upon the position of the 
clasp in its relationship to height of contour of the supporting crown than 
upon the amount of actual contact surface. An adaptation thus made 
as illustrated in Fig. 372 B. 
Precision instruments have been designed for the purpose of locating 
the height of contour and measuring and charting all variations from 
the normal in the inclinations of the supporting teeth, and are useful in 
designing clasps to accommodate these variations. 
Any limited variations from the vertical which may present between 
two or more supporting teeth, either mesio-distally or bucco-linguady, 
if divided evenly in designing the clasp, will greatly increase clasp 
efficiency and decrease the stress imposed upon the supporting abutments. 416 
CROWN AND BRIDGEWORK 
Correct relationship of clasps which are adapted properly to the natural 
crowns of the supporting teeth is illustrated in Fig. 373. 
Selection of Abutment Teeth. 
In the application and construction of clasp dentures, the abutment 
teeth which are adapted best to the requirements and to the successful 
retention of the structure should be selected carefully. 
The natural tendency of the teeth to migrate toward the edentulous 
area results frequently in a mesial or distal inclination from the vertical 
to a degree which, in many instances, would preclude the successful use 
of such teeth as abutments. The teeth selected to support clasps, there- 
fore, should be as nearly vertical as possible and as nearly parallel as 
possible one with the other. Any great variation from relatively vertical 
and parallel lines must be noted and accommodated in the construction of 
the clasps. 
Two clasps usually are adequate to the requirements of fixation for 
any single structure. In bilateral structure the abutment teeth should be 
as nearly opposite each other as possible. In extensive cases where many 
teeth are to be replaced, where only a few abutments remain, and where 
the distribution of the abutments is not favorable to the secure mechanical 
retention of the structure, the use of three, and, perhaps, even four clasps 
may be indicated sometimes; but this is to be determined only by the 
application of sound mechanical principles and by the stability of the 
abutments. 
The selection of the abutment teeth and the construction of clasps to 
meet the requirements will be facilitated by the use of study casts in all 
cases, and the outlines of the arms of the clasps in their relation to the 
crown of the supporting tooth should be determined and traced with an 
indelible pencil. 
Construction of Clasps. 
The construction of clasps should follow the selection of the teeth to 
be used as abutments. Two types of clasps are used, wrought clasps and 
cast clasps. Several methods of procedure are followed in the construc- 
tion of each type. 
Wrought Clasps. Previous to the advent of the casting process, 
wrought clasps, made by adapting heavy clasp-metal plate, 24 to 26 gage, 
to conform to the desired outlines in relation to the crown of the support- CLASP DENTURES 
417 
ing natural tooth, were used exclusively. Clasps made in this manner are 
still used successfully and are indicated frequently. 
While it is true that the casting process offers opportunities for ob- 
taining greater accuracy of adaptation than Is possible by bending heavy 
clasp-metal plate, it is questionable whether absolute accuracy of adapta- 
tion in clasps which are retained in their relationship to the natural crown 
of the supporting tooth by frictional contact is an advantage. 
Fig. 374- 
In this connection it is noteworthy that well-constructed wrought 
clasps, which are wide and which fit closely but not accurately, cause the 
development of less hypersensitiveness in teeth having vital pulps; also 
they possess greater tensile strength. Therefore, they are less likely to 
become brittle and break than are cast clasps. 
If an exceedingly close adaptation of the clasp to the natural crown 
of a tooth having a vital pulp increases the deleterious influence of 
abrasion and promotes hypersensitiveness, which clinical observation seems 
to indicate, this feature, together with that of greater resiliency and greater 
tensile strength, indicate a permanent field of usefulness for wrought 
clasps. 
In any event, the use of wrought clasps is indicated, especially upon 
bicuspid and molar teeth in all cases where a maximum of resiliency 
and of tensile strength is demanded; and particularly in all cases where 
the supporting teeth are not overfirm in their attachment to the investing 
tissues. 
The adaptation of wrought clasps may be obtained in the best manner 
by taking a unit impression in impression compound first and then making 
an amalgam cast. When the cast has been obtained a piece of clasp-metal 
plate, 24 to 26 gage, should be cut to the proper dimensions and annealed 418 
CROWN AND BRIDGEWORK 
thoroughly. Annealing is accomplished best by heating to a cherry red 
and plunging in alcohol. 
With pliers of favorable shape the clasp then should be bent to conform 
closely to that surface of the reproduction of the natural crown which 
presents toward the edentulous space. The arms then should be adapted 
to the buccal and lingual surfaces and trimmed to follow the outlines 
traced previously on the study cast. 
Fig. 375- 
When the adaptation and outlines desired obtain, an occlusal rest made 
of the same gage of clasp-metal should be fitted and attached with solder. 
If additional strength in the arms is required, they may be reenforced by 
fitting first a strip of clasp-metal of the same gage, but much narrower, 
to the center of each arm and then uniting the reenforcement to the clasp 
with 22 karat or 20 karat solder. In both instances the relationship may 
be sustained with small pointed soldering pliers, and without an in- 
vestment, although an investment may be used, if the operator 
prefers. 
When occlusal rest and all necessary reenforcement has been provided, 
the clasp then should be fitted closely to the amalgam cast (Fig. 374) and 
then finished to the point of polishing. 
The reenforcement of the arms may be made with solder alone, but 
the use of solder alone destroys the resiliency of the alloy and makes the 
clasp brittle. 
A more accurate adaptation of the clasp may be obtained by burnishing 
pure gold, about 36 gage, to the cast first, with a generous surplus, and 
then fitting the clasp-metal over it and subsequently uniting the two with 
solder. But, as indicated previously, a closer adaptation than is obtainable 
by conforming the clasp metal directly upon the amalgam cast is of 
doubtful advantage. CLASP DENTURES 
419 
While the amalgam cast made from a single unit impression, taken in 
impression compound, is not an accurate reproduction of the natural tooth 
crown, it is sufficiently accurate for the purpose of making a wrought 
Fig. 376. 
A 
B 
C 
Fig. 377. 
clasp, in which absolute accuracy of adaptation is not desired, for the 
reasons mentioned. 
If preferable, the unit impression may be taken in plaster and the cast 
made with any of the low-heat fusible alloys. In making the cast of 
fusible alloy, the impression should be dried thoroughly and then closed 
at each end with moldine, or with plaster, and the fusible alloy poured 
when cool. (Fig. 375.) Or the impression may be taken in hard impres- 
sion compound if the cast is poured with a low-fusing alloy which may be 
used with impression compound. 
If wrought clasps are to be used on cuspids, half-round clasp-metal 
wire, 14 to 16 gage, should be used instead of plate, and a typical type of 
construction which may be used successfully, as applied to cuspid teeth, 
is illustrated in Fig. 376. Clasps which are to be adapted to cuspids, 
however, probably are made best by casting. 
Cast Clasps. Cast clasps are indicated whenever accuracy of adapta- 420 
CROWN AND BRIDGEWORK 
tion is demanded or is desirable. Several different methods of procedure 
are followed in the construction of clasps by the casting process. 
Simple Method. The simplest method of procedure involves taking a 
unit impression in impression compound and making an amalgam cast of 
the natural tooth crown. When the cast has been obtained it is lubricated 
with thin oil and the clasp formed to the desired outlines and thickness 
Fig. 378. 
with melted casting wax. (Fig. 377 A.) The wax clasp then is loosened, 
the sprue-former attached (Fig. 377 B) and the investment and casting 
made. (Fig. 377 C.) 
A unit impression taken in this manner does not insure a cast which 
is an absolutely accurate reproduction of the natural tooth crown, but 
where the natural tooth crown is of typical normal formation, sufficient 
accuracy to insure a well-adapted clasp obtains. 
In designing and forming the clasp on the amalgam cast, the study 
cast should be used as a guide in all cases. 
Where greater accuracy than is afforded by this simple method of 
procedure is desired, an absolutely accurate and exact reproduction of 
the natural tooth crown must obtain. 
To obtain an exact reproduction of the natural tooth crown the im- 
pression must he taken in sections, and in plaster. This is accomplished CLASP DENTURES 
421 
easily by the use of a separable impression tray, a convenient form of 
which is illustrated in Fig. 378. 
Two different methods of procedure are followed. One may be termed 
the direct method and the other the indirect method. 
Fig. 379. 
Fig. 380. 
Direct Method. In the procedure which may be designated as the 
direct method, the technic followed by Dr. F. E. Roach is productive of 
successful and reliable results. In this procedure the separable impression 
tray is coated with vaseline and filled with what is known commercially 
as “Complaster,” and the impression taken. (Fig. 379.) When the 
complaster has crystallized the tray handle should be removed and the 
impression divided into two lateral halves by the insertion of a sharp 
pointed instrument into the joint. 422 
CROWN AND BRIDGEWORK 
When divided and removed (Fig. 380 A), the two lateral halves of 
the impression should be placed in apposition again by closing the tray and 
inserting the tray handle. (Fig. 380 B.) The impression then should 
be varnished with liquid silex and filled with a casting investment com- 
pound which becomes especially hard after crystallizing. 
Fig. 381 
Fig. 382. 
When the cast has crystallized it should be placed in water, heated 
gradually and boiled until the complaster impression has been disssolved 
completely, leaving a clean, sharp cast. 
The clasp then should be formed directly upon the cast and to the 
outlines and thickness desired with melted casting wax. (Fig. 381.) 
The sprue-former then should be attached securely, the cast submerged 
in cold water and the investment and casting made. 
Indirect Method. In the procedure which may be designated as the 
indirect method, the technic suggested by Dr. N. B. Nesbett is useful and 
reliable. In this procedure a plaster impression is taken, using a separable 
impression tray. When separated, removed, and the two lateral halves 
again brought into apposition, the impression should be varnished, using 
shellac or sandarac varnish. The imprint of the tooth to be clasped then 
should be filled carefully with amalgam and a retaining tack inserted, as 
described previously. When the amalgam has crystallized, the impres- 
sion should be filled with hard plaster. CLASP DENTURES 
423 
When the cast has been obtained, the clasp then should be formed on 
the amalgam reproduction of the natural crown and to the outlines and 
thickness desired. The wax clasp then should be teased loose, detached 
carefully and replaced. The sprue-former now should be attached and 
the investment and casting made. 
The detachment of the amalgam cast from the plaster cast is seldom 
necessary, but if it should be desirable, it may be accomplished easily by 
Fig. 383. 
painting the amalgam and dowel with a thin coating of melted wax 
previous to pouring the impression. If preferable, cement may be used 
instead of amalgam and the cast may be made with one of the so-called 
artificial stone compounds, instead of plaster. 
Clasps in Combination with Full Crown Restorations. The most 
typically ideal application of clasps as retaining agencies obtains when 
they may be used in combination with full crown restorations, and par- 
ticularly when used in combination with full telescope crowns made in 
gold. 
In the construction of full crown restorations which are to support 
clasps, whether made in gold or in combination with porcelain, no effort 
should be made to restore contour. Straight axial walls or surfaces 
should be formed and accommodation for an occlusal rest should be pro- 
vided. (Fig. 382.) 
When the restoration has been constructed and finished, it should be 
placed in position on its supporting abutment, an impression taken in plas- 
ter, and the cast obtained in plaster. The clasp then should be made by 
the method preferred. 
In the application of clasps to full telescope crown restorations made 
by the casting process, a shoulder made for the purpose of affording a 
seat for the clasp may be provided in the construction of the restoration, 
and the clasp then made to fit the shoulder accurately, thus avoiding any 
abnormal contour, as illustrated in Fig. 383. In small fixtures of this 424 
CROWN AND BRIDGEWORK 
type the primary assemblage of the clasps with a small round clasp-metal 
wire, 16 to 18 gage, insures their correct relationship irrespective of the 
type of pontic used, or of how it may be attached to the clasps. Where a 
shoulder is formed in this manner, an occlusal rest is unnecessary, of 
course. 
1*ig. 384 
Clasps with Occlusal Rests in Inlays. Additional efficiency in the 
application of clasps as retaining agencies may be obtained in cases where 
fillings or cavities present, by making a gold inlay first and providing 
accommodation for the occlusal rest in the inlay. The clasp then is made 
with an occlusal rest which fits accurately as illustrated in Fig. 384. 
Formation of Saddles. 
When the clasps have been completed and finished they should be 
placed in position on the supporting abutments and the impression taken 
in plaster. When the impression has been obtained the clasps should be 
placed in their correct position therein and the cast then made in plaster. 
Gold Saddles. If the fixture is to be constructed in gold, the design 
of the saddle should be traced with an indelible pencil and then outlined 
in the surface of the cast by scraping. The saddle then may be made 
either by the casting process, or by swaging, and it should be observed 
that contact between the saddle and clasps obtains. 
In small unilateral structures, the saddle should be designed to meet the 
requirements of stability and the demands of restoration, as indicated 
previously in connection with removable bridgework. 
In maxillary structures of the bilateral type the palatal portion of the 
connecting saddle should be of such proportions only as will insure adequate CLASP DENTURES 
425 
strength in the completed structures. This part of the saddle often may 
be fitted in and around the rugae in such manner as to offer but a minimum 
of mechanical incumbrance, as illustrated in Fig. 385. 
Fig. 385- 
If the casting process is used in the formation of saddles of this type, 
it is advantageous often and frequently necessary to make the casting in 
three separate pieces and unite them subsequently by soldering. In this 
procedure each lateral saddle should be made first and finished and then 
placed in position on the cast and the palatal portion then made to fit 
both. When each segment has been completed, all should be assembled on 
the cast, the relationship sustained with adhesive wax and then removed, 
invested, and united with solder. The same procedure is applicable also to 
extensive mandibular dentures. 
When the saddle has been completed and finished, the clasps should 
be removed from the cast and placed in position on the supporting teeth 
and then united with the saddle by soldering. 
Assemblage of Clasps and Saddle. 
In dentures of any size and particularly bilateral dentures, each clasp 
should be attached to the saddle separately. In obtaining the correct re- 
lationship, the saddle should be placed in position and held securely by 
firm pressure while taking the impression. 
Ifi small unilateral saddles firm pressure may be secured with the 426 
CROWN AND BRIDGEWORK 
finger, or with gentle mandibular pressure, as described previously. In 
bilateral maxillary dentures mandibular pressure also may be used success- 
fully by resting a flat piece of orangewood stick upon the occlusal surfaces 
of the bicuspids or molars on each side of the arch, and then so adjusting 
another piece as to have one end rest upon this and the other upon the 
center of the saddle. The impression then may be obtained successfully 
by using a lower impression tray. 
Fig. 386. 
Certainty and accuracy are insured by taking a separate impression, 
filling it with soldering investment compound and soldering each clasp to 
the saddle separately. When each clasp has been soldered successfully 
the denture should be placed in position and the final bite and impression 
taken. When the case has been mounted upon the articulator, the pontics 
should be selected, adapted and attached in accordance with the require- 
ments, as indicated previously in connection with removable bridgework. 
Application of Lingual Bar in Lower Dentures. 
In bilateral mandibular dentures involving the replacement of the bi- 
cuspids and molars only, the assemblage of the unilateral saddles with a 
lingual bar affords the most ideal type of construction. 
The use of a lingual bar insures adequate strength in the structure, 
leaves the gingival tissues surrounding the remaining natural teeth ex- 
posed freely, and offers a minimum of mechanical incumbrance. 
In the construction of dentures involving the application of lingual 
bars, the clasps and saddles should be made first. Each clasp then should 
be attached to its respective saddle with solder. Saddles and clasps then 
should be placed in position and an impression taken in plaster. The 
impression should be varnished and filled with soldering investment com- 
pound and when the cast is obtained, the lingual bar should be adjusted. CLASP DENTURES 
427 
While the lingual bar may be made by casting, wrought bars made in 
different sizes and in different grades of special alloys are procurable and 
are tougher and stronger. When the bar has been made, or has been 
selected, it should be adapted properly to the curvature and each end 
should rest upon and be in direct contact with the saddle. 
A single layer of thin sheet wax then should be made plastic by dipping 
it in warm water and it should then be molded to conform closely to the 
surface of the cast, against which the bar has been adapted. The bar 
Fig. 387. 
then should be placed in position against the wax and both ends sealed 
securely to the saddles with adhesive wax. 
The thin sheet wax is used only for the purpose of holding the bar 
away from actual contact with the cast, and to a uniform extent at all 
points. This precaution is essential for the reason that close contact of 
the bar with the mucosa in the completed structure is not necessary and 
is often a source of discomfort and should be avoided. 
The cast then should be submerged in water and the relationship be- 
tween the bar and the saddles sustained with investment compound. 
When the investment has crystallized, the wax should be removed with 
boiling water, the cast heated and the bar and saddles assembled with 
solder. (Fig. 386.) 
When the assemblage has been completed, the structure should be ad- 
justed to position and the final bite and impression taken. The cast should 
be made in plaster (Fig. 387), and the bite adjusted and mounted upon 
the articulator. The pontics then should be selected and adapted and the 
case completed in vulcanite in the usual manner. 428 
CROWN AND BRIDGEWORK 
Use of Vulcanite. 
In the construction of vulcanite dentures the clasps should be com- 
pleted first, then placed in position on the supporting teeth and the final 
bite and impression taken. When the impression, with the clasps in 
position, has been obtained, it should be varnished and the inner surfaces 
of the clasps painted with melted wax. An ordinary pin then should be 
forced into the center of the imprint of each tooth clasped and the cast 
made in plaster; 
Fig. 388. 
When the clasps are to be retained in their relation to the structure 
with vulcanite alone, each clasp should be warmed slightly over a flame 
and detached from the cast. The presence of the pin and of the thin coat- 
ing of wax placed on the inner surface of the clasp, previous to pouring 
the cast, makes it possible to remove and replace the clasp with accuracy. 
After detaching the clasp it should be cleaned in acid and replaced 
on the cast. A retaining plate made of clasp-metal, 26 gage, then should 
be adapted to clasp and cast in such manner as to insure strength in the 
attachment of the clasp with vulcanite and to ofifer no interference with 
the correct placement of the pontic immediately adjacent. (Fig. 388.) 
The relationship should be sustained with adhesive wax and the clasp and 
retaining plate then removed, invested and soldered. 
Previous to replacing the clasp upon the cast, the bite should be ad- 
justed and the case mounted upon the articulator. When separated, the 
clasp should be placed in position, and the case completed in the usual 
manner. In investing the case for vulcanite, it is necessary to observe 
that the clasp is protected securely with plaster, and in addition to this, 
the use of cement, placed over and around the clasp previous to investing, 
is frequently a safe precaution. CLASP DENTURES 
429 
Application of Lingual Bar to Vulcanite Saddles. In the construc- 
tion of clasp dentures involving the use of a lingual bar in connection with 
vulcanite saddles, the bite, impression, and cast, with the clasps in posi- 
tion, should be obtained in the manner just described. The lingual bar 
Fig. 389. 
Fig. 390. 
then should be made or selected and adapted as described. Each clasp 
then should be detached from the cast, cleaned in the acid bath and re- 
placed. Small pieces of round, clasp-metal wire, about 16 gage, should 
be fitted in such manner as to afford contact with both bar and clasp. One 
or two wires may be used as the requirements may indicate. The rela- 
tionship between the bar, clasp and wires now should be sustained securely 430 
CROWN AND BRIDGEWORK 
with adhesive wax; all should be detached from the cast carefully, invested 
and soldered. Each clasp should be soldered separately. 
The bite should be adjusted without bar and clasps in position, and 
Fig. 391. 
the cast mounted upon the articulator. When separated, bar and as- 
sembled clasps should be placed in position on the cast (Fig. 389), the 
relationship sustained securely with melted wax and the denture then 
completed in the usual manner. (Fig. 390.) 
Mobility Attachments. 
Clasps are successful retaining agencies in all cases where frictional 
contact and resiliency may serve as a means of retention, and yet also 
permit of release without any displacement of the abutment teeth. But 
in cases where the inclinations of the abutment teeth preclude parallelism, 
and particularly in cases in which an unfavorable distribution of the CLASP DENTURES 
431 
abutment teeth causes the fixture to act as a lever, a rigid attachment 
between clasps and denture often causes the abutment teeth to assume a 
burden of stress beyond the limitations of comfort or of endurance. 
Fig. 392. 
In such cases an indirect connection between the clasp and denture 
and a connection which retains and yet which affords some freedom of 
movement is essential to efficiency, comfort and permanency. 
Any method of attachment which will afford an indirect or flexible, 
and yet secure connection between clasp and denture, therefore, is useful 
in many cases. Attachments of this type are designated as “stress 
breakers” or “stress transmitters.” 
Mobility attachments may consist of a simple hinge or of a length and 
freedom of wire which insures resiliency at the joint (Fig. 391), or any 
of the attachments which are manufactured for this purpose, and all have 
a field of usefulness when indicated. 
A typical class of cases in which attachments of this type are par- 
ticularly useful, and in which the denture becomes a lever and where a 
rigid attachment of the clasps to the structure would soon result in the 
loss of the supporting teeth, is illustrated in cases designed for vulcanite 
in Fig. 392. 
The use of a resilient wire in this manner requires no special technic, 432 
CROWN AND BRIDGEWORK 
Fig. 393- CLASP DENTURES 
433 
Fig. 393- 434 
CROWN AND BRIDGEWORK 
but a special technic is required in the successful application of all forms 
of attachments manufactured for this purpose. 
Separating the Natural Crowns of Teeth. 
In the application of clasps of any type it is never advisable to separate 
the crowns of natural teeth for the purpose of permitting the engage- 
ment of a clasp. The destruction of the contact point and the presence 
of a clasp passing between the natural crowns of teeth only invites failure. 
Use of Ready-Made Clasps. 
Ready-made clasps of various designs and in varying sizes are manu- 
factured ; but since accuracy of design and of adaptation are essential to 
the successful application and to the efficiency of clasps as retaining 
agencies, and since these features are not easily obtained even when the 
clasp is made for the individual case and of a known alloy, it is not reason- 
able to expect a ready-made form to meet the high requirements. 
Furthermore, no knowledge of the composition of the alloy of which 
they are made or of its heat-withstanding and resilient properties elim- 
inates certainty and reliability in their use. 
Summary. 
Whenever the indications are favorable, and whenever all of the re- 
quirements in the composite are met carefully, clasps are the simplest and 
most universally applicable type of retaining agents, and the clasp denture 
is the most generally useful type of removable structure. 
Perhaps the most objectionable feature incident to the application of 
clasp dentures is the frequent development of a hypersensitiveness of the 
tooth structure immediately beneath the clasps in teeth having vital pulps. 
This condition is undoubtedly caused by an induced erosion, and it is 
noticeable that it presents more frequently when cast clasps are used than 
when wide wrought clasps are used. This would indicate that close- 
fitting clasps are more injurious to tooth structure than are those which 
fit less accurately. 
Aside from the development of this hypersensitiveness of tooth struc- 
ture, other injurious effects which may result are largely a question of 
sanitation on the part of the patient. Hence, patients wearing clasp den- 
tures must be advised of the necessity for scrupulous sanitation and careful 
hygiene at all times. 
The typical application of clasp dentures to a variety of cases is illus- 
trated in Fig. 393. Final Considerations. 
CHAPTER XIX. 
INSERTION OF GOLD FILLINGS IN PORCELAIN 
TEETH AND FACINGS. 
Gold fillings are indicated very often in porcelain teeth, or facings 
used in the construction of crowns or of bridgework, in order to simulate 
more closely the remaining natural teeth and thus to comply with the 
requirements of harmony, as has been referred to previously. 
Indications. In the restoration of the crowns of any of the anterior 
teeth, where the remaining adjacent natural teeth are filled with gold more 
or less freely, the restoration may and often should carry one, or perhaps 
two small approximal fillings. 
In bridgework involving the upper anterior teeth, where the lower 
anterior teeth are filled freely with gold, the insertion of one or two 
small fillings in desirable locations often will aid materially in detracting 
from the artificial appearance of the denture. 
Such fillings, however, never should be inserted with a view to making 
the work conspicuous, nor for the exclusive purpose of additional remun- 
eration. They should be no larger than necessary to effect the harmonious 
and legitimate deception which may be indicated thus by the adjacent 
natural teeth. 
Methods. The procedure may be accomplished by any one of three 
different methods: 
First: The preparation of a retentive cavity and filling the cavity 
with gold foil. 
Second: The use of liquid or “Roman” gold, which is painted over 
the desired area, and then fired in the furnace in a manner similar to 
that employed in china decorating. 
Third: The construction of the filling as a part of the backing. 
Gold Foil. In the procedure embracing gold foil, a cavity, in the 
location selected and of the desired form, should be outlined first in the 
facing with a small, fine carborundum stone. (Fig. 394 A.) This out- 
line facilitates the drilling of a cavity and affords a definite marginal edge 
435 436 
CROWN AND BRIDGEWORK 
for the adaptation and finishing of the gold. When formed, adequate 
retention then may be secured by drilling a simple, countersunk cavity 
of sufficient proportions in the center of the outlined area (Fig. 394 B), 
or by cutting retentive grooves. (Fig. 394 C.) 
For the former purpose, applicable more generally to small cavities, 
an inexpensive diamond drill, to be used in the engine, is obtainable. 
Fig. 394. 
Fig. 396. 
Fig. 395- 
(Fig. 395 A.) Where retaining grooves which are adapted best to larger 
cavities are preferred, they may be cut easily with a small copper disk, 
coated with an abrasive, which is prepared for this and similar purposes. 
(Fig. 395 B.) A “cavity cutting” outfit, consisting of a set of engine 
instruments of oval form and graded sizes, and an abrasive compound 
composed of carborundum dust and glycerol, is manufactured for this 
purpose. 
In the application of the first procedure, the free use of oil or glycerin 
facilitates the rapidity of the cutting and entirely eliminates the danger 
of fracturing the facing. 
When the proper retention has been secured, the cavity should be 
cleaned thoroughly with soap and water and dried with alcohol and air. GOLD FILLINGS IN PORCELAIN TEETH AND FACINGS 
437 
It then is filled with small pellets of gold foil in the usual manner and 
finished. (Fig. 394 D.) 
It is advisable usually to defer the insertion of such fillings until after 
the completion of the work, in order to avoid subsequent scratching or 
defacing of the surface. However, it may be necessary at times, or may 
seem desirable, to insert the fillings before the construction of the work 
or the assemblage of the parts. 
This may be essential in bridgework in order to place the cavity in 
the desired location. When such procedure is indicated, it may be 
facilitated by imbedding the facing in a base of impressive compound or 
sealing wax, as a means of holding it securely. (Fig. 396.) 
In porcelain work, the procedure necessarily must be deferred until 
the piece is finished in order to preclude the fusing of the gold. In any 
event the preparation of the cavity and the insertion of the filling should 
be done in immediate sequence. 
Roman Gold. In the use of “Roman” gold, which is prepared for 
decorative purposes, and is quite applicable to this purpose, the cavity 
area should be outlined first, as indicated previously. (Fig. 394 A.) The 
gold then is mixed into a paste of proper consistency and painted thickly 
over the surface. Care should be taken that it follows the cavity margins 
closely and evenly. The facing now should be placed near a flame, or 
close to the previously heated furnace, and allowed to remain there until 
the gold has become thoroughly dry. Then it should be placed in the 
furnace and “fired” until the gold fuses. This may be known readily 
by its vitreous appearance. 
Allowing the case to cool more or less slowly, the filling then may be 
finished and polished with burnishers, or fine cuttlefish disks and the buff 
wheel. 
In gold work, fillings should be made before the final attachment of 
the facing to the metal parts. In porcelain work the lower heat required 
to fuse gold demands that they be made after the completion of the case. 
While this method affords artistic possibilities, the results are likely 
to be less permanent, because of a tendency to flake and chip. 
In Combination with Backing. A method involving less simple 
detail, requiring more time perhaps but productive of very artistic results, 
is also applicable. It consists of making the filling in combination with 
and as a part of the gold backing. 
This procedure is indicated particularly in simulating mesial and distal 
fillings involving the incisal angle. Because of the limited opportunity 
afforded by the ordinary facing for securing adequate anchorage for such 438 
CROWN AND BRIDGEWORK 
fillings, this procedure would often be more difficult by other methods. 
When such a filling is indicated, or where it may be desirable to use 
this method, a flat-back facing should be ground to the proper and re- 
quired adaptation first, and then prepared for the reception of the backing 
in the usual manner. 
That portion of the porcelain facing which involves the location and 
area of the desired gold restoration then should be ground away on a 
Fig. 397- 
slight bevel toward the lingual side until a perfectly smooth marginal out- 
line obtains. (Fig. 397 A.) 
A backing of pure gold, 36 gage, now should be adapted to the facing, 
and burnished close against the cavity margin, allowing a surplus of about 
1-2 millimeter to project beyond the latter, and upon the incisal end. 
(Fig. 397 B.) When this has been accomplished, a piece of 22 karat 
gold plate, 29 gage or 30 gage, should be adapted to the pure gold backing 
extending from the pins to the incisal end, and projecting to the original 
outline of that portion of the facing which has been sacrificed. (Fig. 
397 C.) 
This forms a matrix, outlining the desired formation of the filling, and 
the two backings now should be removed and united with solder in the 
manner previously described in connection with reenforced backings. 
Their detachment from the facing, without danger of changing the 
shape of the thin, pure gold backing, is made possible and facilitated by the 
slight lingual bevel given the cavity walls. 
When their union has been effected, the matrix formed by the two 
backings should be filled with 22 karat solder until the desired contour is 
obtained. (Fig. 397 D.) 
The completed backing then should be adjusted to the facing and 
finished with stones and disks until the adaptation of the backing and the 
contour of the filling are as desired (Fig. 397 E), when the case may be 
completed and finished in the usual manner. 
In obtaining the desired contour of the filling with solder, a high karat 
must be used because of the susceptibility of solder to discoloration, and 
care should be exercised to avoid a pitted surface. GOLD FILLINGS IN PORCELAIN TEETH AND FACINGS 439 
In filling the matrix with solder, the precaution of fitting a piece of 
gold wire or plate into it before the procedure will insure a preservation 
of the adaptation of the pure gold backing to the marginal outlines of the 
cavity. The adaptation might be changed somewhat by shrinkage if 
solder alone were used. CHAPTER XX. 
REMOVING AND REPAIRING. 
As a result of wear, of accident, or of failure to subscribe to the highest 
possibilities in some or in all of the requirements, or because of the 
development of caries, or of more serious pathological conditions involving 
the root-ends of supporting teeth, the removal and repair of restorations 
of all types is often necessary. And whenever necessary, operations of 
this character should be executed with the same deftness and skill which 
should be evidenced in the original construction and oftentimes with even 
greater expediency. 
Removing Full Telescope Crown Restorations. 
While it might be possible in many instances to drill through the 
occlusal surface of full telescope crown restorations, and by making a 
generous opening, to treat and fill pulp canals successfully, and subse- 
quently to restore this surface of the restoration with an inlay; or, while 
it might also be possible to treat caries successfully, or to correct the evils 
of faulty adaptation in a similar manner, still the immediate removal of 
the restoration will facilitate, to a great extent, an observation of any 
therapeutic or mechanical requirements, and is always the best method 
of procedure. 
In the removal of full telescope crown restorations, two methods are 
followed. In one the continuity of the telescoping portion of the restora- 
tion is preserved. In the other it is destroyed. 
Preserving Continuity of Band. Whenever it may be desirable to 
remove the restoration in such manner as to preserve the continuity of 
the telescoping band and thereby permit the repair and replacement of 
the same restoration, the procedure may be effected in a simple manner 
by drilling a small hole through the band at some convenient point imme- 
diately beneath the occlusal surface with a spear drill or round bur, as 
illustrated in Fig. 398. 
When the hole has been drilled entirely through the band, a round 
or fissure bur then should be carried laterally, or mesio-distally, until 
440 REMOVING AND REPAIRING 
441 
the layer of cement between the occlusal surface of the restoration 
and the end of the supporting root has been removed or its integrity 
destroyed. 
A small pointed instrument, not highly tempered, then should be 
introduced into the hole until its end rests firmly upon the supporting root 
at a point relatively near the center. With a fulcrum thus established 
the power of the lever may be used and the restoration easily detached 
and removed. 
Fig. 398. 
Fig. 399- 
Destroying Continuity of Band. Whenever this procedure is not 
successful immediately, or where the replacement of the same restoration 
is not desirable or necessary, removal may be effected in the simplest man- 
ner by destroying the continuity of the band. Special forceps designated 
as “crown-slitting forceps” are made for this purpose. (Fig. 399.) In 
their use the flat beak is placed firmly upon the occlusal surface of the 
restoration and the cutting beak carried beneath the gingival edge of the 
band. Slight compression upon the handles will destroy the continuity of 
the band and lift the restoration off easily. 442 
CROWN AND BRIDGEWORK 
Removing Dowel-Crown Restorations. 
The removal of dowel-crown restorations is more difficult usually, 
and more dangerous always. Great care must be exercised to avoid frac- 
turing the supporting root. 
Whenever applicable, the easiest and simplest method of removing 
dowel-crown restorations would be by the use of excising forceps. 
Fig. 400. 
Fig. 401. 
Fig. 40a. 
Fig. 403. 
In the use of excising forceps, the facing should be broken away first 
and the coping then grasped firmly, and carefully twisted or rotated. 
The power of the lever exerted carefully will result usually in de- 
stroying the integrity of the cement, permitting detachment without injury 
to the supporting root and without mutilation of the coping. 
If detachment is not obtained easily, it may be facilitated by destroying 
the continuity of the coping at some favorable point, as illustrated in 
Fig. 400. This usually may be accomplished easily by the use of a small 
round or fissure bur. 
Where detachment is not to be accomplished easily, however, it may 
become necessary to separate the coping from the dowel. This procedure 
involves drilling through the lingual surface of the coping at a point 
which will destroy the attachment between dowel and coping, leaving the 
dowel in the root, but permitting the removal of the coping. (Fig. 401.) 
The dowel then may be removed subsequently. 
Another method consists in destroying a large portion of the coping REMOVING AND REPAIRING 
443 
with round and fissure burs as illustrated in Fig. 402, but allowing enough 
to remain to facilitate the subsequent removal of the dowel. (Fig. 403.) 
The dowel then may be removed by means of a dowel removing in- 
strument designed for the purpose (Fig. 404), or by drilling it out with 
small round burs. In the use of burs, the smallest size round burs should 
be used, and in their use they should be passed around the periphery 
Fig. 404. 
of the dowel, but at the expense of the dowel and not at the expense of 
the supporting root. The diameter of the dowel should be reduced with- 
out appreciably increasing the diameter of the canal, and care must be 
exercised at all times to avoid perforating or unnecessarily weakening the 
root. 
In the use of the dowel-removing instrument the diameter of the ex- 
posed end of the dowel is reduced first, using a small trephine. The 
reduced end is then threaded with the tap. The socket of the instrument 
is now screwed securely to the threaded end of the dowel, and its removal 
affected by turning the large knurled head. 444 
CROWN AND BRIDGEWORK 
Removing Inlays. 
In the removal of inlays which have been used as abutment attach- 
cnents, great care must be exercised to avoid fracturing the supporting 
natural crown. This precaution, combined with easy removal, usually 
may be accomplished effectually by drilling a hole into the body of the 
inlay at an angle which will accommodate and engage the end of a strong, 
blunt-pointed instrument and permit the use of the instrument as a lever. 
If a hole is made at the proper angle, the inlay usually may be detached 
and lifted out easily. (Fig. 405.) 
Fig. 405- 
Removing All-Porcelain Crown Restorations, 
The removal of all-porcelain crown restorations of any type usually is 
a very simple procedure. When the restoration is of the dowel type, the 
insertion of the beaks of excising forceps into the immediate joint between 
the restoration and the supporting root, followed by the application of 
pressure upon the handles, will wedge the restoration from its attachment 
easily. The dowel then may be removed as indicated. 
The removal of all-porcelain jacket crowns may be effected in the best, 
quickest and easiest manner by cutting a deep groove in the center of 
the labial or buccal surface, extending from the gingival edge to the REMOVING AND REPAIRING 
445 
incisal or occlusal angle, and then destroying the con- 
tinuity by the insertion of a wedge-pointed instrument 
into the groove. 
Removing Fixed Bridgework 
The removal of fixed bridgework usually is attended 
with discomfort and effected with difficulty. When the 
replacement of the same fixture is desirable, fixed struc- 
tures often may be removed successfully and without 
mutilation of attachment or pontics by the use of a per- 
cussion hammer designed and made for this purpose. 
(Fig. 406.) 
In the use of this instrument an effort should be made 
to hook over, or grasp each attachment separately and 
then to loosen each attachment by the continued applica- 
tion of moderately heavy blows with the cylindrical 
weight as a percussion hammer. Detachment and removal 
will follow unless the fixation is so secure as to demand 
the mutilation or partial mutilation of the attachments. 
In this event, the procedures indicated previously for 
each of the various types of attachments may become 
necessary; but whenever the replacement of the same 
fixture is not to be made, detachment and removal should 
be effected in the easiest and simplest manner. 
Repairing. 
When the removal of fixtures which are to be repaired 
and replaced has been effected, the piece then should be 
boiled in dilute hydrochloric acid and washed thoroughly 
in a solution of sodium bicarbonate. Repair then should 
be made in accordance with the requirements of the case, 
and of investing and soldering as indicated previously. 
In repairing either single crown restorations or fixtures 
of any size in which replaceable facings or teeth have 
been used, and where the case must be invested and 
soldered after the pontics have been attached with cement, 
when repair has been effected, all of the pontics must be 
removed and replaced with a new mix of cement. Where 
it may seem desirable, the facings on teeth may be 
removed before subjecting the fixtures to the heat of 
soldering. 
Fig. 406. 446 
CROWN AND BRIDGEWORK 
Removal and replacement of all pontics so attached become necessary 
at all times and in all cases for the reason that the heat required in solder- 
ing disintegrates the cement to such an extent as to result in a very in- 
secure attachment, and an attachment which would not withstand chemical 
action of the oral secretions for any length of time, however perfectly 
the backings may be adapted. 
Therefore, when repair has been effected by soldering, the case should 
be boiled in the acid bath until all facings or teeth may be detached, after 
which they should be recemented. 
Repairing Without Removing. 
The replacement of porcelain pontics of all types is demanded fre- 
quently and constitutes a very large percentage of all repairing which may 
be accomplished without removing the restoration. 
Replacing Cemented Pontics. 
When any of the various types of interchangeable or replaceable 
facings or teeth have been used in the construction, replacement is simple. 
In the procedure, all remaining particles of porcelain and cement which 
may cling to the backing should be removed with a sharp chisel or bur, and 
the substitute then selected, ground to meet the requirements of adaptation, 
and cemented to place. 
Sample molds are useful in making the selection of substitutes, but 
in their absence a small impression should be taken in pink base-plate wax 
and a cast made and used for this purpose. 
Replacing Pin Facings. 
The replacement of pin facings which have been soldered to the basic 
structure is much more difficult, which constitutes another reason for not 
using facings of this type. 
When pin facings are to be replaced, however, several different methods 
of procedure may be followed. 
The simplest and most generally useful method, which is applicable 
either to single crown restorations or to bridgework, consists first in 
removing the remaining pins even with the surface of the backing and 
then drilling holes through the backing, cementing and clinching a new 
facing by bending the pins over upon the backing. REMOVING AND REPAIRING 
447 
In this simple procedure the projecting pins are removed with a small 
bur and a suitable facing selected. The backing now is covered with a 
thin coating of melted wax into which the ends of the pins of the new 
facing are imprinted. Holes of the same diameter as the pins then are 
drilled entirely through the backings at the points indicated. 
Accommodation for the pins being afforded thus, the facing then is 
ground to the proper adaptation. The ends of the pins should extend 
entirely through the backing and to an extent which will permit bending 
them over upon the lingual surface of the backing after cementation. If 
the backing is too heavy to leave the ends of the pins exposed to the 
desired extent, it should be made thinner previously by grinding. 
A 
B 
C 
Fig. 407. 
When the adjustment is completed, the facing then should be mounted 
with cement and the surplus ends of the pins bent with suitable pliers 
in such manner as to be clinched against the backing. After the cement 
has crystallized, the pins then should be flattened, using small stones and 
disks, and then finished and polished smooth. 
Another method, which also is applicable either to single crown restora- 
tions or to bridgework, and which is particularly useful in cases where 
the incisal end of the backing is not heavy or overstrong, consists in cut- 
ting grooves for the accommodation of the pins in the incisal edge of the 
backing, as illustrated in Fig. 407 A. The exact points at which the 
grooves should be placed may be indicated by means of a thin coating of 
melted wax, as suggested previously. 
When the grooves have been cut to the depth required, a backing of 
pure gold, about 36 gage, then should be perforated to accommodate the 
pins. (Fig. 407 B.) The facing then should be adjusted to position 
and the backing adapted closely to the basic structure by burnishing. 
When burnished, the relationship should be sustained with base-plate or 
adhesive wax and facing and backing then removed, invested, and attached 
by soldering. All of the reenforcement which the occlusion will permit 
should be made at the same time. When thus attached and reenforced 
(Fig. 407 C) facing and backing then are cemented to place. 448 
CROWN AND BRIDGEWORK 
Use of Bryant Repair Outfit. 
Another more complicated method of replacing pin facings involves 
the use of what is known commercially as the Bryant repair outfit. In 
the use of this method of procedure, a cone-shaped hole for the reception 
of each pin is drilled through the backing from the lingual surface, using 
a standard cutting bur for the purpose. (Fig. 408 A.) When the holes 
A 
B 
C 
D 
Fig. 408. 
Fig. 409. 
are drilled for each pin, the facing then is adjusted to the proper adapta- 
tion by grinding, after which the pins are threaded with a tap which is a 
part of the outfit. (Fig. 409.) The facing then is placed in position 
and a cone-shaped nut supplied especially for this work is adjusted to the 
threaded pin and screwed to place until the facing is retained firmly. 
(Fig. 408 B.) Any and all surplus subsequently is finished smooth and 
flush with the contour of the supporting basic structure. (Fig. 408 C.) 
The adjustment of the nut is accomplished with facility by means of a 
special wrench. (Fig. 408 D.) 
Cast Gold Pontics. 
In the replacement of posterior pontics, cast gold pontics often may 
be fitted to the basic structure and used to better advantage than would 
be afiforded by replacement with porcelain. REMOVING AND REPAIRING 
449 
In the replacement of porcelain pontics with cast gold pontics, casting 
wax should be made plastic and molded to fit the basic structure and to 
meet all of the requirements of occlusion and of contour in the usual 
manner. The pattern then should be invested and the casting made, fin- 
ished and cemented in the same manner as indicated for inlays. 
Use of Silicate Cements. 
In the replacement of pin facings, where the pins remain, the use of 
silicate cements often may afford successful results. 
Repairing Porcelain Bridgework. 
The repair of porcelain bridgework usually is a difficult and somewhat 
hazardous procedure. The removal must be made in accordance with 
the requirements of the case and along the lines suggested. 
When the fixture has been removed, it should be cleaned thoroughly 
first with soap and water. Then it should be boiled in dilute hydrochloric 
acid and afterward immersed in a tepid solution of sodium bicarbonate. 
Any remaining organic matter then must be removed before repair is at- 
tempted. The removal of organic matter may be accomplished success- 
fully only by the application of heat. 
In this procedure the piece should be placed in the furnace while the 
muffle is just warm, and the temperature then increased gradually until a 
red heat obtains and all organic matter is burned out. It then should be 
allowed to cool slowly. Any additions of new porcelain made necessary 
by the requirements of repair then may be made and fused successfully, as 
described previously. 
In large restorations any danger of fracture, or of injury to the fixture 
which may be caused by too rapid heating or cooling, in burning out 
organic matter may be overcome entirely by previously investing the case, 
using an investment compound composed largely of asbestos. CHAPTER XXI. 
FINISHING AND POLISHING. 
The wonderful luster and smoothness of surface obtainable by finish- 
ing and polishing gold and platinum and their alloys attracts the admira- 
tion of all and particularly of those who manipulate them. 
In all lines of purely artistic endeavor in which gold and platinum 
are used, finishing and polishing are a means of enhancing beauty. But 
in dental restorations of any type, finishing and polishing constitute an 
important part of construction and, irrespective of the skill displayed 
otherwise, unless a fine finish is obtained, the final product is not a work 
of art, nor does it subscribe to the highest possibilities from the viewpoint 
of hygiene and sanitation. 
A definition of finishing and polishing might be given as a succession 
of scratches all running in the same direction and growing finer and finer. 
And in proportion as the scratches grow finer, the surface becomes 
smoother and the luster more accentuated; and in proportion as smooth- 
ness and luster increase, hygiene and sanitation are rendered more possi- 
ble. 
Therefore, since both art and sanitation are thus obtained, restorations 
of any size and of all types must be finished properly and polished highly, 
irrespective of the time required. 
Finishing. When the piece has been treated to the acid bath and all 
traces of acid removed by immersing in a solution of sodium bicarbonate, 
then it should be finished. 
The preliminary finishing may be accomplished in the simplest and 
most expedient manner by means of stones and disks used in the engine. 
Beginning with carborundum and vulco-carborundum stones of 
medium coarseness and suitable size, all sharp edges and angles should 
be removed, inaccessible pockets and solder pits obliterated, and all sur- 
faces worked down until proper contour and definite finishing lines obtain. 
All grooves and sulci in the occlusal surfaces of telescope crowns 
should be made smooth and well defined, and where facings of any type 
have been used in the construction of anterior dowel-crown restorations, 
the natural shape and form of the lingual surface should be reproduced 
450 FINISHING AND POLISHING 
451 
in the backing, as illustrated in Fig. 410. This may be accomplished easily 
with small knife-edge stones and round burs. 
Coarse, then medium, and finally fine disks should be used until all 
deep scratches are removed, and until the desired contour and smoothness 
of surfaces obtain. 
Polishing. This procedure then should be followed by polishing with 
felt and brush wheels on the lathe. The primary polishing may be secured 
Fig. 410. 
Fig. 411. 
in the best manner by the use of a thin-edge felt wheel (Fig. 411) and a 
moistened abrasive powder or compound, and the felt wheel should be 
soaked previously in water in order that it may absorb and carry the 
abrasive during the procedure. 
When the desired smoothness of surface has been obtained thus, the 
final polishing should be given, first using a stiff brush-wheel (Fig. 412 A) 
with the abrasive, and then using a polishing compound, such as tripoli, 
or whiting, or precipitated chalk. This procedure should be followed 
with a soft brush-wheel (Fig. 412 B) and finally with a “buff” wheel 
(Fig. 412 C) until a highly polished surface is obtained. 
The more highly all surfaces of metal are polished, the less susceptible 
they are to discoloration, and the more permanent will be the polish. 
Fine silex and pumice stone, mixed into a thick paste, are used as an 
abrasive, and tripoli, jewelers’ rouge and various other polishing com- 
pounds are used with whiting, or precipitated chalk, with the “buff” wheel 
for a final polishing. 452 
CROWN AND BRIDGEWORK 
A 
B 
c 
Fig. 412. FINISHING AND POLISHING 
453 
Facilitating Procedure. As full telescope crown restorations are 
somewhat difficult to handle while polishing, various styles of “crown- 
holders” have been devised for facilitating this procedure. (Fig. 413.) 
Filling the restoration with impression compound, or with sealing wax, 
and then inserting a piece of wood into it while still plastic, is recom- 
mended also, but this procedure is objectionable because of the difficulty 
of removing the compound after the polishing is completed. 
Fig. 413. 
While dowel crowns are not quite so difficult to handle in polishing, 
the use of a jewelers’ small pin vise sometimes may be found convenient. 
Precautions. Although it is scarcely possible to give too high a polish 
to the surfaces of metal which are to be fixed permanently in the mouth, 
it is, however, quite possible and indeed sometimes quite easy to polish 
through the thinner portions of bands and saddles in the use of disks 
and felt wheels. Hence, extreme care should be exercised to prevent 
such a mishap, as well as to preclude any unnecessary thinning of such 
parts. 
Cementing Replaceable Teeth and Facings. 
When replaceable teeth or facings are used, the restoration should be 
finished to the point of polishing previous to the cementation of the teeth 
or facings; and if duplicates are to be made they should be ground to the 
proper and required adaptation at this time. 454 
CROWN AND BRIDGEWORK 
The original teeth or facings then should be cleaned with alcohol or 
chloroform, dried thoroughly, and cemented to place. When the cement 
has crystallized and all surplus has been removed, the final requirements' 
in connection with polishing should be observed. 
Gold Plating. 
An increased artistic effect and a more attractive finish may be ob- 
tained by subjecting the piece to the electroplating process, after it 
has been highly polished. This imparts a uniform rich yellow color to 
all metal surfaces and affords a surface of pure gold which is not so 
easily attacked and discolored by the chemical action of the secretions. 
Solutions for this purpose may be made by dissolving fifteen grains 
of the chlorid of gold in a porcelain or glass vessel containing about four 
ounces of distilled water, and then adding to this a like quantity of water 
into which about thirty or forty grains of pulverized potassium cyanid 
also have been dissolved previously in a similar vessel. This is known as 
the “cyanid solution,” the approximate formula for which, as generally 
employed, is as follows: 
Gold chlorid gr. xv. 
Potassium cyanid gr. xxx to xl. 
Distilled water oz. viii. 
A small, ordinary “primary” or “dry-cell” battery may be used and 
the work to be plated should be attached to the negative pole and then 
suspended in the solution with a piece of thin, pure gold plate, likewise 
suspended from the positive pole, avoiding contact between the two. 
A simple plug, known as the “Teter,” also may be used. In the use 
of this plug the current used for illumination purposes may be taken 
directly from the socket, resistance being obtained through the use of an 
eight-candle-power bulb in serial connection with the plug. 
If the piece is well finished, highly polished and then washed with 
bicarbonate of soda to remove all traces of extraneous matter, and then 
fastened to the pole with small copper wire, coiling the wire so as to 
have a well distributed contact over the surface of the piece to be plated, a 
few minutes’ immersion in the solution will produce the desired result, 
after which it should be highly polished again with the “buff” wheel. For 
heavy plating this procedure should be repeated two or three times. 
Prepared Solutions. Solutions which may be used without a battery 
are prepared for this purpose and while they seem to afford good results, 
the deposit of gold is not so heavy and hence more temporary, and the 
solution can be used only until it becomes inactive. FINISHING AND POLISHING 
455 
In the use of commercially prepared solutions a sufficient quantity 
should be placed in a porcelain or glass vessel and heated until warm, and 
the work then attached to a strip of pure zinc and immersed therein. 
Moderate heat and slight agitation will effect the desirea result in a 
few moments and the effectiveness of the solution may be increased by 
suspending a small piece of pure gold plate on another zinc strip hooked 
over the edge of the vessel so that the gold is immersed. CHAPTER XXII. 
MOUNTING. 
In all restorations which are to enter into a fixed relationship with 
the supporting abutment teeth, the permanency of the adaptation and the 
success of the restoration will depend entirely upon the manner in which 
fixation obtains. 
Hence, irrespective of the ingenuity displayed in designing, or of the 
skill evidenced in the construction of restorations of any type or size, their 
final fixation to the supporting abutments is an important feature which 
must be observed carefully and skilfully at all times. 
This procedure is termed “mounting” and the secure fixation and 
permanency of relationship is obtained by means of a suitable mounting 
medium. 
Requirements of Mounting Medium, 
Since much depends upon the mounting medium, any agency used for 
this purpose must subscribe to the following requirements: 
First: It must be sufficiently plastic to be moldable in order that all 
intervening space may be filled completely. 
Second: It must possess a fineness of texture which will permit an 
accurate adjustment of the relationship. 
Third: It must harden or crystallize to a degree which will insure 
strength. 
Fourth : It must be non-irritating. 
Fifth: It must be reasonably impervious and insoluble. 
But two agencies now in use subscribe in a general way to all of 
the requirements of a successful mounting medium—cement and gutta- 
percha. 
Cement. When a maximum of permanency in fixation is desired, 
cement is the one dependable mounting medium, and the zinc-oxyphosphate 
cements are used almost exclusively. They possess all of the requirements 
to a favorable degree and when mixed properly, and used in the absence of 
moisture, a maximum of strength and permanency is insured. In order 
456 MOUNTING 
457 
that the maximum of efficiency may be insured, however, dental cements 
must be mixed to the proper consistency, must be spatulated thoroughly, 
and moisture must be excluded during crystallization. 
In addition to an observation of these manipulative requirements, in- 
creased efficiency will be obtained by applying firm pressure and by avoid- 
ing any disturbing influence during crystallization. 
The application of pressure minimizes expansion and thus increases 
the accuracy of adaptation in the relationship; and crystallization obtains 
more perfectly when any disturbing influence is avoided during the period 
of chemical activity. 
If these features are observed, the adhesive properties of cement so 
strengthen and protect the supporting tooth or root as to insure a maxi- 
mum of strength and of permanency in the attachment of the restoration, 
which, in itself, is an advantage of incalculable value. 
The only feature incident to the use of cement as a mounting medium 
which might be regarded, in any manner, as a disadvantage, is the diffi- 
culty attached to the removal of restorations so mounted, but it is this 
very feature which insures permanency. 
Therefore, when permanency is desired or is demanded, cement 
should be used, but in cases where the possible necessity for removal is 
anticipated, no effort toward obtaining permanency should be made, and a 
more temporary form of mounting should be used. 
Gutta-percha. The vegetable compound known as gutta-percha is a 
useful mounting medium for single crown or fixed bridgework restora- 
tions whenever the possibility of removal may be anticipated, or where 
it may be desirable or advisable to provide for such contingency. 
Gutta-percha is a tough, strong product and is prepared for dental 
purposes in base-plate form and in two colors, pink and white. It may 
be made plastic by heat if carefully applied, and is soluble in chloroform, 
xylol and some of the essential oils. These features make it adaptable as 
a mounting medium and useful in all cases where permanency is not 
demanded, and, therefore, where the use of cement would be contra- 
indicated. 
When manipulated carefully and properly, even fairly permanent re- 
sults may be obtained. But it is a refractory product and difficult to 
manipulate, and, while it is not plastic at body temperature, it is not 
reliable as a permanent mounting medium, for the reason that sufficient 
plasticity to make it moldable and adaptable requires the incorporation 
of a small proportion of paraffin or of one of the waxes, or the use of 
one of its solvents. 458 
CROWN AND BRIDGEWORK 
The incorporation of wax reduces its refractory properties, but it is 
this very property which insures the strength demanded of a permanent 
mounting medium. And the use of one of its solvents in obtaining 
plasticity invariably will result in shrinkage. Hence the use of gutta- 
Fig. 414. 
percha is indicated only in cases where a temporary medium is demanded 
or is desirable. 
Preliminary Requirements. Previous to the final mounting of resto- 
rations of all types and of all sizes, each single unit must be adjusted to 
its proper position on the supporting abutment, and all of the require- 
ments of construction observed carefully. 
It is particularly essential that the occlusion should be perfected pre- 
vious to mounting. Articulating paper should be used in all cases. When MOUNTING 
459 
all necessary adjustments have been made, the restoration should be 
polished again. 
And, as a final procedure, the supporting abutment teeth should be 
disinfected and made aseptic by the free use of alcohol and hot air. 
Mounting with Cement. 
Since absolute immunity from moisture is essential to success and 
permanency when cement is to be used as the mounting medium, every 
precaution to exclude moisture should be taken; and since cement 
crystallizes more or less rapidly, thus limiting the time which may be 
Fig. 415. 
consumed in the operation, every convenience which will facilitate and 
expedite the procedure should be provided in advance. 
The use of non-absorbent cotton rolls and of the saliva ejector should 
be made in all cases, and will be found immeasurably helpful at all times. 
When all supporting teeth or roots are protected thus, or otherwise, 
they should be dried thoroughly, using alcohol and air freely. It then 
should be observed that the fixture itself is perfectly dry, after which 
the cement should be mixed properly and to the proper consistency and 
the mounting made. 
As a further means of facilitating the procedure, the cement should 
be mixed by an assistant whenever possible. 
In mounting anterior crowns the field of operation may be kept free 460 
CROWN AND BRIDGEWORK 
from moisture by the use of non-absorbent cotton rolls, as illustrated in 
Fig. 414. 
Dowel Crowns. In mounting dowel crowns the canal and basal end 
of the root should be bathed in alcohol, using a suitable, blunt root-canal 
instrument with cotton, and then dried thoroughly with air. Warm air, 
of course, is preferable. 
The cement now should be mixed properly and then pumped into 
the canal until it is filled completely, using a blunt, smooth root-canal 
plugger for the purpose. When the canal has been filled completely, the 
dowel and the basal surface of the coping should be covered with cement, 
Fig. 416. 
Fig. 417. 
and the restoration forced to its proper position and held firmly in this 
relationship by pressure with the fingers until the cement has crystallized, 
after which all surplus should be removed. 
Telescope Crowns. In mounting telescope crowns, posterior abut- 
ments may be protected from moisture by the use of cotton rolls placed 
buccally and lingually. These may be held in position by the fingers, 
or, in the lower arch, by means of a clamp, as illustrated in Fig. 415. 
The same detail of procedure then should be observed, except that 
it is not necessary usually to apply the cement directly to the root, but a 
sufficient quantity should be placed inside of the crown, in which pro- 
cedure it must be smeared over the surfaces in such manner as to avoid 
any confined air. 
Full or partial crown restorations made in gold may be seated more 
firmly by tapping them to place, using a heavy blunt-pointed instrument 
(Fig. 416) and a hand-mallet for this purpose. And in full telescope MOUNTING 
461 
crowns in which a peripheral band is used, the adaptation of the gingival 
edge of the band often may be perfected immediately after the mounting 
by holding the crown firmly in position with the fingers and then burnishing 
this edge to conform closely to the periphery of the supporting abutments. 
A useful form of burnisher, adapted particularly to this purpose and to 
similar purposes, is illustrated in Fig. 417. 
When the mounting has been made satisfactorily, the relationship may 
be sustained during crystallization by a firm closure of the teeth, or by 
closing firmly upon a cotton roll or small piece of soft wood and retaining 
the firm closure until complete crystallization obtains. 
Porcelain Jacket Crowns. Greater care, of course, must be taken in 
mounting porcelain jacket crowns. Firm, but gentle pressure, may be 
applied only with the fingers, or, in posterior restorations, by closing upon 
a cotton roll. 
In mounting porcelain jacket crowns the color of the cement used 
always should approximate the color of the restoration closely in order 
that any appreciable or undesirable change may not be caused. When 
some slight change is desirable, however, it may be produced by the use 
of a color lighter or darker, as may be indicated. 
Inlay Attachments. In mounting inlay attachments it should be ob- 
served always that they are seated firmly. Moderately heavy tapping 
with a suitable blunt instrument is safe usually and, when safe, is always 
advisable as a means of insuring a maximum of accuracy in the adaptation. 
Mounting Two or More Restorations. When two or more single 
unit restorations are to be mounted at the same sitting, and when they 
are to serve independently of each other, each should be mounted 
separately. 
By mounting each single unit separately, no special speed is required, 
and where no effort need be made to expedite the procedure, greater 
accuracy probably is assured. 
Fixed Bridgework. In mounting fixed bridgework where two or 
more attachments necessarily must be mounted simultaneously, the greatest 
possible care always must be exercised, first, in obtaining a free exposure 
of the supporting abutments; and second, in obtaining the exclusion of 
moisture during and immediately following the procedure. 
Fixed bridgework which is adapted properly and accurately should 
assume its proper relationship with the supporting abutments readily, and 
without any appreciable binding or displacement. 
And, yet, because of the varying inclinations of the abutments, or 
because of the unreliability of the materials and compounds used in the 462 
CROWN AND BRIDGEWORK 
construction, or both, some little effort frequently is required in the final 
and accurate adjustment of the relationship between the attachments and 
the abutments. 
Any necessary adjustment of the relationship always should be made 
before attempting the final mounting. If great difficulty is experienced 
in seating the fixture, inaccuracy undoubtedly results, and, if inaccuracy 
obtains, it must be corrected before the final mounting. 
Any appreciable binding, or any displacement of the abutments, means 
discomfort and invites failure, and when inaccuracy exists to this extent, 
warpage or distortion is the probable cause. And when warpage or dis- 
tortion presents, the attachments, one or the other, or both, or all, must 
be separated from the pontics and again placed in position on the abut- 
ments, an impression taken and the fixture reassembled. 
But if no very great binding or displacement is required, the final 
adjustment may be perfected and the mounting may be accomplished with 
greater ease and facility in many cases, and, particularly, in large fixtures, 
by placing the fixture in position and allowing it to remain unmounted 
for one, or possibly two days. Final mounting then may be effected with 
ease and facility. If worn for a longer period than one or two days, 
however, distortion and inaccuracy in the adaptation probably would 
follow. 
When the final adjustment is perfected and is satisfactory, the at- 
tachments should be dried with alcohol and air, and the abutments then 
treated as indicated. The cement should now be mixed and applied to 
each abutment and to each attachment and the fixture then forced to 
place and firm pressure maintained with the fingers, or by means of soft 
wood or cotton rolls, until the cement has crystallized. 
In mounting fixed bridgework which includes a saddle as a part of 
the basic structure, care must be exercised to insure the removal of all 
surplus cement which may be forced in between the saddle and the 
mucosa before crystallization is complete. If not removed before crystalli- 
zation is complete, all particles which may find lodgment upon this surface 
of the saddle would be sources of irritation. 
The retention of any surplus cement may be prevented, first, by placing 
a length of flattened silk tape floss, such as is used in prophylaxis, between 
the saddle and the mucosa, and mounting the fixture. When the mounting 
has been completed, and while the fixture is held with firm pressure, each 
end of the floss then may be grasped and drawn backward and forward 
over the entire surface of the saddle until the removal of all surplus is 
insured. Lubricating the tape floss with vaseline will facilitate the 
procedure. MOUNTING 
463 
Removable Bridgework. In mounting removable bridgework two 
methods of procedure are followed. The best results will be obtained by 
fastening the retaining attachments to the structure previously with melted 
base-plate wax, and then mounting the entire structure all at one time. 
The use of melted wax sustains the relationship of the attachments while 
mounting, precludes the ingress of cement into the joint between the tele- 
scoping parts, and permits of ready detachment after complete crystalliza- 
tion obtains. 
Fig. 418. 
When it may not be possible or advisable to follow this method of 
procedure, or where some advantage may be gained from mounting the 
attachments to the supporting abutments separately, each attachment may 
be mounted independently of the structure, and the structure then forced 
to place while the cement is still plastic. 
In either method of procedure, firm pressure should be maintained, as 
indicated previously, and the structure should not be disturbed until com- 
plete crystallization and secure fixation of the attachments has been 
insured. 
Mounting with Gutta-percha. 
Gutta-percha as a mounting medium is applicable only to full-crown 
restorations of the dowel and telescope type. 
Dowel Crowns. In mounting dowel crowns the gutta-percha should 
b*e cut into long, narrow strips and these strips then saturated well with 
oil of cajoput or eucalyptus. They then should be placed upon some 
form of heating iron and allowed to remain until plasticity obtains. Slow, 
indirect heating is essential to workable plasticity, which quality is not 
obtainable by the application of direct heat. A convenient form of heat- 464 
CROWN AND BRIDGEWORK 
ing iron designed for the purpose by Dr. George Evans is' illustrated in 
Fig. 418. 
When the required degree of plasticity obtains, a strip of suitable 
length should be coiled around the dowel, as illustrated in Fig. 419 A. 
The basal end and canal of the supporting root now should be moistened 
with tepid water and the restoration forced gently to place. This pro- 
cedure should be repeated until the gutta-percha is molded to meet the 
requirements of close adaptation and accurate relationship. (Fig. 419 B.) 
When these requirements have been met, the restoration should be 
placed upon the heating iron again and the supporting root then dried. 
Fig. 419 
The surfaces of basal end of the root and of the root canal now should 
be moistened slightly with oil of cajeput or oil of eucalyptus, or with a 
moderately thick solution of gutta-percha in chloroform, and the restora- 
tion then forced to place firmly. A spray of cold water then should be 
directed upon the restoration until the temperature is reduced to normal, 
when the mounting is completed. 
Telescope Crowns. In mounting full telescope crowns, the same pro- 
cedure should be followed, except that the gutta-percha should be cut 
into pieces of convenient form and size. 
Fixed Bridgework. When gutta-percha is to be used in mounting 
fixed bridgework, the same technic should be followed, but the adaptation 
to each abutment should be made separately. 
Removing Restorations Mounted with Gutta-percha. 
In the removal of restorations which have been mounted with gutta- 
percha the procedure is facilitated by the application of heat. This may 
be made successfully by protecting the soft tissues with cotton rolls and 
using a hot-air syringe, or by creating heat from friction. A leather, 
moose-hide, or felt polishing wheel placed in the engine and revolved 
rapidly, will accomplish the latter. MOUNTING 
465 
Combining Cement and Gutta-percha. 
In mounting dowel crowns the combined advantages of cement and 
gutta-percha, to a limited extent, may be obtained by molding the gutta- 
percha to the dowel, as indicated, and then completing the mounting with 
cement. Increased strength in the attachment to the supporting root ob- 
tains, and removal in the event of necessity is facilitated, but the latter 
feature probably is obtained at the expense of permanency, and hence 
no great advantage follows. 
Fig. 420. 
Temporary Mounting. 
For all temporary purposes and in all cases where only a temporary 
mounting is desired or is required, the use of any of the low-heat tem- 
porary stoppings, molded and adapted, as indicated for gutta-percha, will 
answer the purpose nicely and affords the advantage of facility and 
expediency. 
Precautions. 
In order to guard against the possibilities of unnecessary irritation 
of the investing tissues in the use of cement as a mounting medium, the 
final precaution of carefully and thoroughly removing all surplus must be 
exercised always. To this end, round or flattened floss ligatures should 
be passed between and around the abutment teeth, and between and be- 
neath all pontics in all cases. If this precaution is not taken, surplus in 
the form of nodules might remain, as illustrated in Fig. 420. These 
would be sources of irritation until dislodged or dissolved. 466 
CROWN AND BRIDGEWORK 
The Care of Dental Bridgework. 
In the replacement of missing teeth the first duty of the dentist is 
to place the oral cavity in a state of health. The second is to give to 
the patient only such service as will promote and insure health. And the 
third is to teach the patient the importance of oral hygiene, and the 
manner in and by which sanitation may be secured, and health promoted 
and maintained. 
Those who wear fixed bridgework should be cautioned as to the neces- 
sity for scrupulous sanitation at all times, and should be taught how to 
obtain it. And those for whom removable bridgework, clasp dentures 
and partial restorations of all types are constructed, should receive similar 
careful instruction. 
Removable structures should be cleansed before and after each meal, 
whenever possible, and should always be removed over night and placed 
in a glass containing a mild antiseptic solution. This permits the tissues 
to rest and capillary circulation to become normal. 
The remaining natural teeth must be kept clean, independently of the 
structure, and the structure itself, whether large or small, should be 
cleansed thoroughly, using tepid water, soap, and some form of abrasive 
as often as may be necessary to insure thorough asepsis. 
In any line of human endeavor, proficiency, if inspired by ambition, 
will be acquired by application and perseverance. INDEX 
Abutments in Bridgework, 249 
Abutment Teeth, Selection of, 416 
Acetone, Use of, 73 
Acid Bath, 54 
Adjusting Cusps to Band, 138 
Finishing, 139 
Soldering, 139 
Advantages of Replaceable Facings, 159 
Use of Replaceable Facings and Cast 
Cusps, 160 
Alloying, 32 
Alloys, Base Metal, 38 
Brass, 38 
Dorrance’s Alloy, 39 
Flux for Base Metals, 40 
Fusible Alloys, 39 
German Silver, 39 
Silver Solder, 39 
Soft Solder, 40 
Alloys of Gold, 34 
Of Metal, 34 
All-Porcelain Crown Restorations, Re- 
moving, 444 
Amalgam, Restorations With, 83 
Amalgam Cast, 152 
Anatomical Requirements for Artificial 
Teeth, 22 
Approximal Contact, 22 
Marginal Angles, 23 
Reproduction of Natural Tooth Form, 
22 
Anchorage for Bridgework, 15 
Annealing, 32 
Anterior Fixtures, in Pontics, 346 
In Porcelain Bridgework, 353 
Anterior Pontics, 3x8 
Color, 319 
Length, 319 
Median Line, 318 
Width, 318 
Anterior Teeth, Application of Gold 
Telescope Crowns, 164 
Application of Casting Process to Gold 
Crowns, 144 
Application of Lingual Bar in Lower 
Dentures, 426 
Application of Vertical Attachments, 
378 
Casting, 378 
Cavity Preparation, 378 
Direct Method, 383 
Inlays, 378 
Matrix Inlays, 383 
Application to Anterior Teeth, 164 
Casting, 167 
Construction, 164 
Coping, 165 
Flat-back Facings, 166 
Replaceable Facings, 166 
Soldering, 167 
Application to Posterior Teeth of Gold 
Telescope Crowns, 159 
Articulation, 23, 288 
Articulation and Occlusion, 23 
Articulation, 24 
Centric Occlusion, 23 
Eccentric Occlusion, 23 
Functional Activity, 24 
Functional Occlusion, 23 
Malocclusion, 23 
Occlusion, 23 
Traumatic Occlusion, 23 
Articulation of Pontics, 344 
Articulators, 48 
Artificial Crowns, Indications for, 12 
Primitive Applications, 4 
Artificial Crowns, Requirements of, 16 
Anatomical, 22 
Basic Requirements, 22 
Esthetic Requirements, 24 
Mechanical Requirements, 24 
Pathological Requirements for, 19 
Physiological Requirements for, 17 
Therapeutic Requirements, 21 
Artificial Restoration of Lost Tissue, 
401 
Assemblage, Bridgework, 248 
Cast, Final, 322 
Clasps and Saddle, 425 
Pontics, 344 
Porcelain Bridgework, 353 
Removable Bridgework, 369 
Assembled Abutments, 391 
Assembling, 402 
Attachments for Bridgework, Tempo- 
rary, 312 
Inlays, 312, 461 
Mobility, 430 
Attachments, Retaining, 370 
Application of Vertical, 378 
Friction Plate and Jacket, 371 
Full Telescoping Crown, 372 
Horizontal, 373 
Paralleling Retaining, 375 
Split-Post and Tube, 372 
Vertical, 370 
467 468 
INDEX 
Attachments to Supporting Tooth, 26 
Dowel Attachment, 27 
Telescoping Attachment, 26 
Band, Adjusting Cusps to, 138 
Cone-shaped, 122 
Destroying Continuity of, 441 
Making, 120 
Preparation for Combination Inlay 
and Partial Peripheral, 102 
Preparation for Dowel Crowns With- 
out Peripheral, no 
Preserving Continuity of, 440 
Soldering, 122 
Telescope Crown with Peripheral, 81 
Base Metal Alloys, 38 
Base Metals, 30 
Flux for, 40 
Basic Principles in Preparation of 
Teeth and Roots, 78 
Variations, 79 
Basic Requirements, for Artificial 
Crowns, 22 
For Porcelain Bridgework, 365 
For Soldering, 55 
Basic Rules for Fixed Bridgework, 
349 
Bite, 129, 3x6 
Blowpipe, Combination, 60 
Mouth, 59 
Oxhydrogen, 65 
Borax, 57 
Brass, 38 
Bridgework, 243 
Classification, 247 
Fixed, 248 
Methods in, 247 
Removable, 248 
Bridgework, Anchorage for, 15 
Care of Dental, 466 
Fixed and Removable Combined, 251 
Bridgework, Fixed, 243, 248, 251, 253, 
461, 464 
Basic Rules, 349 
Field of Usefulness, 259 
Bridgework, History of, 10 
Bridgework, Movable-Removable, 384 
Bridgework, Porcelain, 351 
Basic Requirements, 365 
Bridgework, Removable, 463 
Bridgework, Removing Fixed, 445 
Bridgework, Repairing Porcelain, 449 
Bridgework, Requirements in, 249 
Mechanical, 249 
Physiological, 249 
Bridgework, Selection of Methods, 252 
Bridgework, Temporary Attachments in, 
313 
Lingual Supports in, 313 
Occlusal Stress in, 314 
Pontics, 316 
Bridgework, Types of, 248 
Abutments, 248 
Assemblage, 248 
Attachments, 249 
Cantilever, 248 
Complex, 248 
Compound, 248 
Pontics, 249 
Retaining Attachments, 249 
Simplex, 248 
Brown Crown, History of, 9 f 
Bryant Repair Outfit, Use of, 448 
Buttner Crown, History of, 8 
Cantilever Bridges, Gold Crowns Acting 
as, 142 
Cantilever Bridgework, 248, 282 
Care of Dental Bridgework, 466 
Caries, Extensive, Requiring Crowns, 13 
Carving, 146 
Cast, 42, 129, 318, 369 
Cast, Amalgam, 70, 152 
Made of Plaster or Investment Com- 
pound, 71 
Cast Cusps, Use of Replaceable Facings 
and, 160 
Cast Gold Pontics, 448 
Cast of Model, 42 
Cast, Separating from Impression, 46 
Casting, 67, 76, 146, 167, 327, 333, 378, 
398 
Casting Alloys, 35 
Casting Base Metal Alloys, 78 
Casting, Direct Method, 144 
Casting Flasks, 77 
Casting, Indirect Method, 150 
Casting Machines, 76 
Casting Porcelain, 242 
Casting Process, 68 
Amalgam Casts, 70 
Application of, 68 
Attachment of Sprue-formers, 72 
Casting, 76 
Casting Base Metal Alloys, 78 
Casting Flasks, 77 
Casting Machines, 78 
Casting to Porcelain, 77 
Casts Made of Plaster of Investment 
Compound, 71 
Direct Method, 69 
Heating Flask, 75 
Impression Compound Impressions, 69 
Indications, 70 
Indirect Method, 69 
Investment, 73 
Investment Compounds, 74 
Large Patterns, 73 
Making Wax Patterns, 70, 71 
Plaster Impressions, 71 
Removing Investment After Casting, 
77 INDEX 
469 
Casting Process, Small Patterns, 73 
Technic of, 68 
Use of Acetone, 73 
Vitreous Compounds, 74 
Casting Process to Gold Crowns, Ap- 
plication of, 144 
Casting, Removing Investment After, 
77 
Casting to Porcelain, 77 
Cement, 456 
Combining with Gutta-percha, 465 
Mounting with, 459 
Restoration with, 82 
Cemented Pontics, Replacing, 446 
Cementing and Riveting, 192 
Casting with Lockit Cups, 192 
Soldering and Riveting, 193 
Cementing Replaceable Teeth and 
Facings, 453 _ 
Cementing Retaining Attachments to 
Abutments, 408 
Centric Occlusion, 23 
Chemical Action of Metals, 30 
Clasp Dentures, 252, 410 
Advantages of, 411 
Application, 412 
Bicuspids and Molars, 412 
Cuspids, 412 
Economy, 411 
Incisors, 412 
Indications, 412 
Retention, 411 
Simplicity, 411 
Clasps and Saddles, Assemblage of, 
425 
Clasps as Retaining Agencies, Effi- 
ciency of, 414 
Clasps, Construction of, 416 
Clasps, Use of Ready-Made, 434 
Clasps, Wrought, 416 
Cast, 416 
In Combination with Full Restora- 
tions, 423 
With Occlusal Rests in Inlays, 
424 
Classification of Metals, 30 
Coin Gold, 35 
Coloring Material in Porcelain, 
219 
Color of Metals, 30 
Color Problem, 204 
Combination Gold and Porcelain Bridge- 
work, 361 
Dowel Crowns, 361 
Gold Crowns, 361 
Making Porcelain Sections, 362 
Complex Bridgework, 248, 279 
Compound Bridgework, 248, 273 
Compounds, Impression, 47 
Compounding Solders, 38 
Construction of Clasps, 416 
Cast Clasps, 419 
Clasps in Combination with Full 
Crown Restorations, 423 
Clasps with Occlusal Rests in Inlays, 
424 
Direct Method, 421 
Indirect Method, 422 
Simple Method, 420 
Wrought Clasps, 416 
Contact, Approximal, 22 
Coping, 165, 168 
Construction of, 171 
Coping, Casting Method, 182 
Indirect Method, 183 
Soldering Method, 183 
Coping, Root-End, 105 
Coping With Full Peripheral Band, 
171 
Direct Method for, 171 
With Reinforced Band, 173 
Coping With Partial Bands, 174 
Construction by Burnishing, 175 
Direct Method for, 174 
Coping Without Band, 175 
Direct Method for, 176 
Indirect Method for, 176 
Crowns Acting as Cantilever Bridges, 
Gold, 142 
Crowns, Applied to Separated Molar 
Roots, 140 
Crowns, Artificial, 4 
Brown, 9 
Buttner, 8 
Dodge, 5 
Foster, 5 
Gates-Bonwill, 6 
Gold Telescope, 6 
How, 8 
Howland-Perry, 7 
Logan, 9 
Mack, 5 
Porcelain Jacket, 10 
Webb, 9 
Weston, 8 
Crowns, Conditions Requiring, 13 
Accidental Causes, 13 
Discoloration, 15 
Extensive Caries, 13 
Malformation, 14 
Malposition, 14 
Crowns, Dowel, 80 
Crowns, Gold, Manufactured or Ready- 
Made, 144 
Crowns, Indications for, 12 
Crowns, of Teeth, Separating Natural, 
434 
Crowns, Open-Face, 142, 301 
Crowns, Preparation, For Full Shoulder 
Gold, 89 470 
INDEX 
Crowns, Preparation for Full Shoulder 
Porcelain, 93 
Preparation for Open-face Partial, 
I03 
Preparation for Partial Shoulder 
Gold Crowns, 90 
Preparation of Roots for Dowel, 104 
Preparation for Shoulder, 88 
Preparation Without Peripheral Band 
for Dowel, no 
Crowns, Restoration of Continuity of 
Natural, 82 
Crowns, Shaping Remaining Natural, 84 
Crowns, Telescope, 80 
Cusps, Adjusting to Bands, 138 
Forming the, 129 
Density of Metals, 31 
Diatoric Teeth, 326 
Die and Die-plate Methods, 130 
Adjusting Cusps Without Casts, 132 
Adjusting Swaged Cusps to Casts, 132 
Individual Dies, 131 
Use of Die-plates, 132 
Dies, Making Special, 133 
Discoloration, 15 
Direct Method in Casting, 144 
Additional Contouring, 146 
Carving, 146 
Casting Wax, 145 
Investing and Casting, 146 
Telescoping Peripheral Band, 145 
Dodge Crowns, History of, 5 
Dorrance’s Alloy, 39 
Dowel, 178, 236 
In Multi-rooted Teeth, 179 
Dowel, Requirements of, m 
Alloys for, 112 
Shape of, 112 
Dowel Crowns, 80, 168, 385, 460, 463 
Color, 170 
Coping, 168 
Dowel, 168 
Display of Gold, 171 
Harmony, 171 
Requirements, 169 
Type, 170 
Dowel Crowns, All-Porcelain, Ready- 
made, 196 
Adaptation to Root, 198 
Application of, 197 
Indications for, 197 
Selection of, 197 
Requirements of, 197 
Dowel Crowns, Method of Construction, 
171 
Dowel Crowns in Porcelain and Gold 
Bridgework, 361 
Dowel Crowns in Porcelain Bridge- 
work, 351 
Dowel Crowns, Porcelain in Construc- 
tion of, 233 
Dowel Crowns, Preparation of Roots 
for, 104 
Dowel Crowns, Removing Restorations, 
442 
Dowel Crowns, Temporary, 194 
Dowel Crowns Without Peripheral 
Band, Preparation for, no 
Ductility of Metals, 31 
Eccentric Occlusion, 23 
Efficiency of Clasps as Retaining 
Agencies, 414 
Height of Contour, 415 
Electricity, Application of in Soldering, 
66 
Enamel, Removal of, 106 
Enamel Cleavers, Use of, 107 
Epitome, 27 
Esthetic Requirements in Artificial 
Crowns, 27 
Excising Remaining Natural Crowns of 
Bicuspids and Molars, 106 
Excising Remaining Natural Crowns of 
Incisors and Cuspids, 106 
Facings, Advantages of Replaceable, 
159 
Application of Porcelain, 180 
Cementing Replaceable, 453 
Insertion of Gold Fillings in Porcelain 
Teeth and, 435 
Flat-back, 166 
Removable and Replaceable, 185 
Application of, 186 
Indirect Method, 186 
Replaceable, 166 
Replacing Pin, 446 
Soldering Porcelain, 62 
Facings, Porcelain, 184 
Removable, 185 
Replaceable, 185, 319, 333 
Silicate Cement, 342 
Facings, Use of Flat-Back Facings, 188 
Application of, 189 
Backings for, 189 
Casting in Connection With, 189 
Flatback Pin Facings, 323, 325 
Reinforced Backings for, 189 
Soldering in Connection With, 189 
Facings, Use of Soldered, and Swaged 
Cusps, 161 
Feldspar, 219 
Field of Usefulness of Metals, 33 
Finishing and Polishing, 450 
Facilitating Procedure, 453 
Finishing, 450 
Polishing, 451 
Precautions, 453 INDEX 
471 
Fixation as a Principle, 254 
Advantages of, 256 
Indications for, 256 
Fixed Bridgework, 461, 464 
Fixed Bridgework, Basic Rules, 349 
Fixed Bridgework, Construction, 
292 
Attachments, 292 
Dowel Crowns, 293 
Full Crown Restorations, 293 
Groove Attachments, 296 
Partial Crown Attachments, 295 
Partial Shoulder Crowns, 295 
Pin Attachments, 299 
Telescope Crowns, 294 
Fixed Bridgework, Field of Usefulness, 
259 
Simplex Type, 262 
Group No. 1, Class 1—Replacing 
Missing Central 
Incisor, 262 
Class 2—Replacing 
Missing Lateral 
Incisor, 262 
Class 3—Replacing 
Missing Central 
Incisor, 262 
Class 4—Replacing 
Missing Lateral 
Incisor, 264 
Class 5—Replacing 
a Missing Cen- 
tral and Lateral 
Incisor, 264 
Class 6—Replacing 
Missing Central 
and Both Lateral 
Incisors, 266 
Class 7—Replacing 
Missing Centrals 
and One Lateral 
Incisor, 266 
Class 8—Replacing 
Missing Four In- 
cisors, 268 
Class 9—Replacing 
Missing Cuspid, 
268 
Class 10—Replacing 
Missing First Bi- 
cuspid, 268 
Group No. 2, Class 1—Replacing 
Missing First Bi- 
cuspid, 268 
Class 2—Replacing 
Missing Second 
Bicuspid, 268 
Class 3—Replacing 
Missing First 
Molar, 270 
Fixed Bridgework, Simplex Type 
Group No. 2, Class 4—Replacing 
Missing First 
Molar and Sec- 
ond Bicuspid, 270 
Class 5—Replacing 
Missing First 
Molar and First 
Bicuspid, 273 
Class 6—Replacing 
Missing First 
and Second Mo- 
lars, 273 
Class 7—Replacing 
Missing Second 
Molar and Sec- 
ond Bicuspid, 273 
Compound Type, 273 
Class 1—Replacing Missing Lat- 
eral Incisor and First 
Bicuspid, 273 
Class 2—Replacing Missing Cus- 
pid and Second Bi- 
cuspid, 273 
Class 3—Replacing Missing Cuspid 
and First Bicuspid, 277 
Class 4—Replacing Missing Bi- 
cuspids (Unilateral), 277 
Class 5—Replacing Missing Lat- 
eral Incisor and Both 
Bicuspids, 277 
Class 6—Replacing Two Bicuspids 
and First Molar, 278 
Class 7—Replacing Bicuspids and 
First and Second Mo- 
lars, 278 
Class 8—Replacing Missing Lat- 
eral Incisor, Bicuspids 
and First Molar (Uni- 
lateral), 278 
Complex Type, 278 
Class 1—Replacing Missing Inci- 
sors and Cuspids, 278 
Class 2—Replacing Missing Inci- 
sors and First Bicuspids, 
279 
Class 3—Replacing Missing Inci- 
sors, Cuspid and First 
Bicuspid, 280 
Class 4—Replacing Missing Lateral 
Incisors, Cuspids and 
Bicuspids, 282 
Class 5—Replacing Missing Inci- 
sors and Bicuspids, 282 
Class 6—Variations, 282 
Cantilever Type, 282 
Class 1—Replacement of Missing 
First Molar, 282 
Class 2—Replacement of Missing 
First Bicuspids, 283 472 
INDEX 
Extension Fixtures, 283 
Interrupted Fixtures, 283 
Saddle Fixtures, 283 
Fixed Bridgework, Principles and 
Technics of, 243, 248, 253 
Fixed Bridgework, Removing, 445 
Flame for Soldering, 58 
Flatback Facings, Use of, 188 
Casting, 337 
Made Replaceable, 338 
With Pins, 323, 335 
Fluids, Separating, 45 
Flux, 219 
For Base Metals, 40 
Liquid, 57 
Use and Proper Application of, 56 
Formation of Saddles, 424 
Forming the Cusps, 129 
Bite, 129 
Impression, 129 
Impression and Casts, 129 
Foster Crown, History of, 5 
Fractured Roots, Treatment of, 114 
Free Exposure of Basal Surface of 
Roots, 116 
Friction Plate and Jacket Attachments, 
.371 
Indications, 371 
Full Crown Restorations in Fixed 
Bridgework, 292 
Full Telescope Crown, 386 
Full Telescope Crown Attachments, 373 
Indications for, 373 
Full Telescope Crown Restorations, Re- 
moving, 440 
Fusibility of Metals, 31 
Gates-Bonwill Crown, History of, 6 
German Silver, 39 
Gingival Edge of Facing in Relation- 
ship to Mucosa, 320 
Gingival Extensions of Porcelain, 339 
Gingival Tissue, Restoration of, 356 
Gold, 33 
Gold, Alloys of, 34 
Gold and Porcelain Bridgework, Com- 
bination, 361 
Gold As a Solder, Pure, 64 
Liquid, 66 
Gold Crowns, 361 
Acting as Cantilever Bridges, 142 
Application of Casting Process in, 
144 
Applied to Separated Molar Roots, 
140 
Manufactured or Ready-Made, 144 
Preparation for Full Shoulder, 90 
Preparation for Partial Shoulder, 
90 
Variations of Technique, 147 
Gold Crowns, Variations of Technique, 
Accurate Interior Adaptation, 147 
Short Roots, 148 
Gold Fillings in Porcelain Teeth and 
Facings, Insertion of, 435 
Gold Foil, 435 
Gold Plating, 454 
Prepared Solutions, 454 
Gold Pontics, Cast, 448 
Gold, Recovering and Refining Waste, 
4i 
Wet Method, 41 
Gold, Refining Scrap, 40 
Gold, Roman, 437 
Gold Telescope Crowns, 117 
Indications for, 117 
Methods of Construction, 118 
Requirements, 118 
Gold Telescope Crowns, History of, 5 
Gold Telescope Crowns for Porcelain 
Facings, 158 
Indications, 158 
Goslee Tooth, 329 
Backings Made in Sections, 330 
Gum Block Teeth, Soldering, 63 
Gum Enamel Bodies, 221 
Gutta-percha, 457 
Combining Cement and, 465 
Mounting with, 463 
Removing Restorations Mounted with, 
464 
Groove Attachments, 297 
Anterior Teeth, 297 
Casting Method for, 297 
Posterior Teeth, 299 
Soldering Method for, 297 
History, 1 
Horizontal Attachments, 373 
Application of, 395 
Indications, 395 
Howland-Perry Crown, History of, 7 
How Crown, History of, 8 
Impressions, 43, 316 
Impression Compounds, 47 
Impression Tray, 43 
Plaster of Paris, 43 
Pouring the Cast, 46 
Self-Separating Plaster, 47 
Separating Cast from Impression, 
46 
Separating Fluids, 45 
Impression and Casts, 42, 129 
Impression Compound Impressions, 69 
Impression Plaster, 71 
Impression Tray, 43 
Indirect Method in Casting, 150, 152 
Amalgam Cast, 152 
Unit Impression, 152 INDEX 
473 
Inlay and Partial Peripheral Band, 
Preparation for Combination, 102 
Inlay Attachments, 461 
Inlays, Application of Vertical Attach- 
ments, 378 
Inlays, As Attachments, 303 
In Anterior Teeth, 304 
Posterior Teeth, 305 
Separable Pins, 306 
Use of Matrix, 306 
Without Matrix, 306 
With Pins, 305 
With Teeth Having Vital Pulps, 305 
Inlays as Attachments in Pulpless 
Teeth, 312 
Inlays as Bridgework Attachments, 100 
Preparation of Anterior Teeth, 101 
Preparation of Posterior Teeth, 102 
Inlay in Combination with Partial Pe- 
ripheral Band, 309 
Inlays, Matrix, 383 
Inlays, Removing, 444 
Insertion of Gold Fillings in Porcelain 
Teeth and Facings, 435 
Combinations of Backings, 437 
Indications for, 435 
Gold Foil, 435 
Methods, 435 
Roman Gold, 437 
Investing, 146 
Investment, 49, 73 
Investment and Investment Compounds, 
49. 
Preliminary Requirements, 50 
Purpose of Investment, 49 
Removing Parts from Cast, 50 
Removing Wax, 50 
Requirements of Investment, 50 
Investment Compounds, 74 
Requirements of, 51 
Investment, Soldering Without, 57 
Iridium, 34 
Jacket Crowns, For Restoring Pulpless 
Teeth, 212 
Direct Method, 214 
Indirect Method, 213 
Making Casts, 212 
Making the Matrix, 215 
Jacket Crowns, Mounting, 231 
Jacket Crowns, Porcelain, 461 
History of, 10 
Jacket Crowns, Porcelain, 201 
Advantages of, 201 
Hygiene and Sanitation, 202 
Indications for, 203 
Influence of Light, 202 
Maintenance of Health, 202 
Masticatory Efficiency, 202 
Non-conductivity, 202 
Jacket Crowns, Porcelain, Pulp Conser- 
vation, 202 
Requirements, 203 
Strength, 202 
Jacket Crowns, Restorations Without 
Shoulder, 217 
Jacket Crowns, Technics of Construc- 
tion, 205 
Amalgam Cast, 209 
Impression and Casts, 206 
Impression of Adjacent Teeth, 207 
Indestructible Surfaces, 211 
Plaster Casts, 210 
Protection with Silicate Cement 
Crowns, 208 
Taking the Bite, 207 
Temporary Protection, 208 
Unit Impression, 206 
Karat, Defined, 33 
Kaolin, 219 
Lingual Bar in Lower Dentures, Appli- 
cation of, 426 
Lingual Bar in Vulcanite Saddles, Ap- 
plication of, 429 
Lingual Supports in Bridgework, 313 
Liquid Gold Solder, 66 
Logan Crown, History of, 9 
Mack Crowns, History of, 5 
Making Special Dies, 133 
Carved Cusps and Special Dies, 135 
Dies and Counter Dies, 133 
Malformation, 14 
Malleability of Metals, 31 
Malocclusion, 23 
Malposition, 14 
Mechanical Requirements in Artificial 
Crowns, 24 
Adaptation, 24 
Strength, 26 
Stress, 25 
Median Line, 318 
Metallurgy, 29 
Metals, 29 
Metals, Alloys of, 34 
Alloys of Gold, 34 
Casting Alloys, 35 
Coin Gold, 35 
Gold and Platinum Alloys, 35 
Platinized Gold, 35 
Metals, Classification of, 30 
Base Metals, 30 
Chemical Action of Metals, 30 
Color of Metals, 31 
Density of Metals, 31 
Ductility of Metals, 31 
Fusibility of Metals, 31 
Malleability of Metals, 31 474 
INDEX 
Metals, Classification of, Noble Metals, 
30 
Odor and Taste of Metals, 30 
Physical Properties of Metals, 30 
Tenacity of Metals, 31 
Metals, Field of Usefulness, 33 
Gold, 33 
Iridium, 33 
Karat, Defined, 33 
Platinum, 34 
Metals, Physical Processes, 32 
Alloying, 32 
Annealing, 32 
Solder, 32 
Tempering, 32 
Welding, 32 
Methods of Construction of Dowel 
Crowns, 171 
Construction of Coping, 171 
Mobility Attachments, 430 
Model, 42 
Movable-Removable Bridgework, 384 
Mounting, 456 
Mounting Medium, Requirements of, 
456 
Precautions in, 465 
Temporary, 465 
Mounting with Cement, 459 
Dowel Crowns, 460 
Fixed Bridgework, 461 
Inlay Attachments, 461 
Mounting Two or More Restorations, 
461 
Porcelain Jacket Crowns, 461 
Removable Bridgework, 463 
Telescope Crowns, 460 
Mounting with Gutta-percha, 463 
Dowel Crowns, 463 
Fixed Bridgework, 464 
Telescope Crowns, 464 
Natural Crowns of Teeth, Separating, 
434 
Noble Metals, 30 
Occlusal Stress, 249 
In Bridgework, 314 
Occlusion, 23, 288 
Traumatic, 250 
Odor and Taste of Metals, 30 
Open-Face Crowns, 142, 301 
Anterior Teeth, 301 
Construction, 143 
Indications, 142 
Posterior Teeth, 302 
Operative Procedure, 95 
Anterior Teeth, 96 
Posterior Teeth, 98 
Restoring Roots, 98 
Paralleling Converging or Diverging 
Teeth, 85 
Operative Procedure, 86 
Variations, 88 
Paralleling Retaining Attachments, 375 
Partial Crown Attachments, In Fixed 
Bridgework, 295 
Partial Shoulder Crowns, 156 
Direct Method in Casting, 156 
Indirect Method in Casting, 156 
Partial Shoulder Crowns in Fixed 
Bridgework, 295 
Pathological Requirements for Arti- 
ficial Crowns, 19 
Focal Infection, 19 
Patterns, Large, 73 
Small, 73 
Perforated Roots, Treatment of, 113 
Peripheral Band, Preparation for Com- 
bination Inlay and Partial, 102 
Preparation for Dowel Crowns With- 
out, no 
Telescope Crown with, 81 
Phonation, 251 
Physical Processes of Metals, 32 
Physical Properties of Metals, 30 
Physiological Requirements for Arti- 
ficial Crowns, 16 
Pulp Conservation, 19 
Pulp Devitalization, 17 
Pin Attachments, 299 
Vital Pulps, 299 
Pin Facings, Replacing, 446 
Pin Inlay Attachments, 309 
Anterior Attachments, 309 
For Stabilizing Loose Teeth, 310 
Posterior Attachments, 310 
Plating, Gold, 454 
Plaster of Paris, 43 
Platinized Gold, 35 
Platinum, 34 
Platinum Alloy, 35 
Platinum Solders, 36, 64 
Polishing, 450, 451 
Pontics, 249 
Pontics, All-Porcelain, 398 
Pontics, Articulation, 344 
Pontics, Assembling, 344 
Anterior Fixtures, 346 
Posterior Fixtures, 346 
Requirements, 345 
Soldering, 347 
Pontics, Attachment of, 405 
Pontics, Bucco-Lingual Dimensions of 
Posterior, 343 
Pontics, Cast Gold, 448 
Pontics, Replacing Cemented, 446 
Pontics, Selection of Type, 316 
Cast, 318 
Anterior, 318 INDEX 
475 
Pontics, Selection of Type, Bite, 316 
Impression, 316 
Pontics, Solid Cast, 341 
Pontics, Use of Replaceable Facings as, 
406 
Pontics, With Porcelain Root Exten- 
sions, 321 
Posterior, 325 
Porcelain, Advent of, 3 
Porcelain and Gold Bridgework, Com- 
bination, 361 
Porcelain Bridgework, 351 
Anterior Fixtures, 354 
Assemblage, 353 
Attachments, 351 
Dowel Crowns, 351 
Indications for, 351 
Restoration of Gingival Tissues, 
356 
Posterior Fixtures, 357 
Telescope Crowns, 353 
Porcelain Bridgework, Basic Require- 
ments, 365 
Porcelain Bridgework, Repairing, 449 
Porcelain Casting, 242 
Porcelain Compounds, 218 
Coloring Material in, 219 
Composition, 218 
Feldspar, 219 
Flux, 219 
Kaolin, 219 
Silica, 219 
Porcelain Compounds, Use and Manipu- 
lation of, 222 
Applying and Building, 223 
Carving and Contouring, 225 
Cooling and Annealing, 229 
Final Bake, 227 
Fusing, 228 
Heating Furnace, 228 
Mixing Body, 223 
Placing Crown in Furnace, 227 
Porosity, 230 
Precautions Incident to Fusing, 227 
Primary Bake, 226 
Pyrometer Furnaces, 229 
Selection of Color, 222 
Shrinkage, 226 
Staining and Coloring, 231 
Tests, 229 
Variations in Shading, 224 
Porcelain Crowns, 199 
Porcelain Crowns, Preparation for Full 
Shoulder, 93 
Porcelain Crowns, Use of Full, 180 
Advantages, 180 
Application, 181 
Direct Method for, 180 
Porcelain Facings, Gold Telescope 
Crowns with, 518 
Porcelain Facings, Use of, 184 
Indications for, 185 
Porcelain, Gingival Extensions of, 339 
Porcelain, High and Low Fusing Com- 
pounds, 220 
Comparative Advantages, 220 
Gum Enamel Bodies, 221 
Shrinkage, 221 
Porcelain in Construction of Dowel 
Crowns, 233 
Anterior Crowns, 239 
Bicuspid Crowns, 239 
Casting Porcelain, 242 
Coping, 234 
Direct Method, 235 
Dowel, 236 
Full Bands, 235 
Impression and Bite, 237 
Indications for, 233 
Indirect Method, 235 
Investment, 238 
Leaving Pins Exposed, 239 
Molar Crowns, 240 
Partial Bands, 241 
Reinforced Coping, 240 
Requirements of, 234 
Root Preparation, 234 
Selection of Porcelain Facing, 237 
Soldering, 234 
Soldering Facing, 239 
With Facing, 240 
Without Facing, 241 
Without Band, 242 
Without Facing, 241 
Porcelain Jacket Crowns, 461 
History of, 10 
Porcelain Sections, 362 
Porcelain Teeth and Facings, Insertions 
of Gold Fillings, 435 
Porcelain Teeth as Veneers, 232 
Porcelain Teeth or Facings, Applica- 
tion of, 180 
Posterior Fixtures, in Pontics, 346 
In Porcelain Bridgework, 357 
Posterior Pontics, 325 
Bucco-Lingual Dimensions of, 343 
Posterior Teeth, Application of Gold 
Telescope Crowns to, 159 
Precautions in Mounting, 465 
Precautions in Porcelain Bridgework, 
409 
Preparation of Abutment Teeth for 
Inlay Attachments, 100 
Preparation of Roots for Dowel 
Crowns, 104 
Anterior Maxillary Roots, 108 
Excising Remaining Natural Crowns 
of Bicuspids and Molars, 106 
Excising Remaining Natural Crowns 
of Incisors and Cuspids, 106 476 
INDEX 
Preparation of Roots for Dowel Crowns, 
Mandibular Anterior, and Bicus- 
pid and Molar Roots, no 
Operative Procedure, 105 
Preparation for Dowel Crowns with 
Full Peripheral Band, 105 
Removal of Enamel, 106 
Root-end Copings, 105 
Shaping Basal Surface of Root, 108 
Shaping Periphery of Root, 107 
Use of Enamel Cleavers, 107 
Preparation of Teeth and Roots, 78 
Preparation of Teeth Having Vital 
Pulps for Attachments for Bridge- 
work, 100 
Preparation for Combination Inlay and 
Partial Peripheral Band, 102 
Requirements for, 102 
Preparation for Dowel Crowns With- 
out Peripheral Band, no 
Alloys for Dowels, 112 
Preparation of Root Canals, in 
Requirements of a Dowel, in 
Shape of Dowel, 112 
Preparation for Full Shoulder Gold 
Crown, 89 
Preparation for Full Shoulder Porce- 
lain Crowns, 93 
Coronal Preparation, 95 
Preparation of Teeth Having Vital 
Pulps, 95 
Preparation of Pulpless Teeth, 95 
Shoulder Preparation, 95 
Preparation for Partial Shoulder Gold 
Crowns, 90 
Enamel Margins, 92 
Preparation of Anterior Teeth, 91 
Preparation of Posterior Teeth, 91 
Preparation for Shoulder Crowns, 88 
Full Shoulder Crown Restorations, 89 
Preparation for Simple Groove Attach- 
ments, 103 
Pulp Conservation for Artificial 
Crowns, 19 
Pulp Devitalization for Artificial 
Crowns, 17 
Pure Gold as a Solder, 64 
Ready-Made Clasps, Use of, 434 
Refining Scrap of Gold, 40 
The Roasting Method, 40 
Removable Bridgework, 248, 251, 361, 463 
Abutment Teeth, 369 
Advantages, 367 
Assemblage, 369 
Indications, 368 
Requirements, 368 
Retaining Attachments, 369 
Saddles, 369 
Study Casts, 369 
Removing All-Porcelain Crown Resto- 
rations, 444 
Removing and Repairing, 440 
Removing Dowel Crown Restorations, 
442 
Removing Fixed Bridgework, 445 
Removing Full Telescope Crown Res- 
torations, 440 
Destroying Continuity of Band, 441 
Preserving Continuity of Band, 440 
Removing Inlays, 444 
Removing Restorations Mounted with 
Gutta-percha, 464 
Requirements for Crown and Bridge- 
work, 222 
Requirements of Clasp Dentures, 413 
Requirements of Investment Com- 
pounds, 51 
Character of Investment Compounds, 
52 
Drying and Pleating, 53 
Heat, 51 
Non-Crystallizing Compounds, 52 
Shrinkage and Expansion, 52 
Strength, 52 
Requirements of Mounting Medium, 456 
Cement, 456 
Gutta-percha, 457 
Preliminary Requirements, 458 
Repairing, 445 
And Removing, 440 
Porcelain Bridgework, 449 
Without Removing, 446 
Replaceable Facings, 185, 319, 333 
Casting, 333 
Pontics with Porcelain Root Exten- 
sions, 321 
Recent Extraction, 320 
Relationship of Gingival Edge of 
Facing to Mucosa, 320 
Swaging, 334 
Swaging in Sections of Two or 
Three, 335 
Replaceable Facings, Advantages of, 
*59 
Replaceable Facings as Pontics, 406 
Replaceable Teeth, All-Porcelain, 323, 
325 
Advantages, 325 
Backing, 326 
Casting, 327 
Diatoric Teeth, 326 
Indications, 325 
Reinforcing, 327 
With Solder, 327 
Replaceable Teeth and Facings, Ce- 
menting, 453 
Replacing Cemented Pontics, 446 
Replacing Pin Facings, 446 
Restoration, Vulcanite, 407 INDEX 
477 
Restoration of Continuity of Natural 
Crown, 82 
Restoration with Cement, 82 
Restoration with Amalgam, 83 
Restoring Single Roots of Molar Teeth, 
141 
Retaining Attachments, 370 
Requirements, 370 
Retaining Attachments of Different 
Types, Combining, 396 
Indications, 396 
Roman Gold, 437 
Root Canal, Preparation of, 111 
Saddle Fixtures, 285 
Abrasion, 290 
Adaptation of, 285 
Articulation and Occlusion, 288 
Attachments, 286 
Elongation, 289 
Grinding Natural Teeth, 289 
Hygiene and Sanitation, 286 
Instruction to Patients, 287 
Opening the Bite, 289 
Paralleling Abutments, 287 
Pontics, 286 
Requirements in, 285 
Strength of, 286 
Structural Formation, 286 
Saddles, 369, 375 
Requirements, 374 
Vulcanite, 374 
Saddles, Application of Lingual Bar to 
Vulcanite, 429 
Saddles, Assemblage, 425 
Saddles, Construction of, 397 
Casting, 398 
Saddles, Formation of, 424 
Gold Saddles, 424 
Saddles, Use of, 358 
Vulcanite, 407 
Seamless Method of Constructing Gold 
Telescope Crowns, 139 
Sectional Method for Gold Telescope 
Crowns, 119 
Cone-shaped Band, 122 
Contouring, 126 
Fitting, 124 
Gingival Edge, 125 
Making the Band, 120 
Occlusal Edge, 126 
Soldering the Band, 122 
Separating Fluids, 45 
Shaping Remaining Natural Crown, 84 
Shoulder Crowns, 150 
Shoulder Crowns, Partial, 156 
Shoulder Crowns, Preparation for, 
88 
Preparation for Partial, 90 
Preparation for Full Porcelain, 93 
Silica, 219 
Silicate Cement Facings, 342 
Silicate Cements, Use of, 449 
Silver Solder, 39 
Simple Groove Attachments, Prepara- 
tion for, 103 
Simplex Bridgework, 248, 262 
Soft Solder, 40 
Solder, 32, 36 
Compounding, 38 
Gold Solders, 37 
Platinum Solders, 36 
Soldering, 54, 139, 167, 327, 337, 347 
Soldering, Basic Requirements, 55 
Acid Bath, 55 
Application from Distribution of 
Heat, 56 
Apposition, 56 
Borax, 57 
Freedom from Oxidation, 54 
Liquid Flux, 57 
Precautions, 55 
Use and Proper Application of Flux, 
56 
Soldering, Technic of, 57 
Application of Electricity, 66 
Autogenous Solder, 66 
Balling Up of Solder, 62 
Base Metal Contamination, 65 
Combination Blowpipe, 60 
Cooling After Soldering, 64 
Effect of Gravity, 62 
Flame for, 58 
Liquid Gold Solder, 66 
Management of Solder, 61 
Mouth Blowpipe, 59 
Oxhydrogen Blowpipe, 65 
Platinum Solder, 64 
Pure Gold as a Solder, 64 
Shrinkage of Solder, 63 
Soft Soldering, 66 
Soldering Gum Block Teeth, 63 
Soldering Porcelain Facings, 62 
Soldering With an Investment, 60 
Soldering Without an Investment, 
57 
Sweating Method of Soldering, 65 
To Prevent Unsoldering, 65 
Solid Cast Pontics, 341 
Split-Post and Tube Attachments, 372 
Application of, 387 
Indications, 372 
Sprue-formers, Attachment of, 72 
Steele’s Posteriors, 331 
Supplying Missing Teeth, 257 
Anterior Teeth, 259 
Cantilever Type, 259 
Posterior Teeth, 259 
Supplying a Single Missing Tooth, 257 
Supplying Two Missing Teeth, 258 478 
INDEX 
Swaged Cusps, Use of Soldered Facings 
and, 161 
Swaging, _ 137, 334, 402 
In Sections of Two or Three, 335 
Taking the Bite, 47 
Technic for Soldering, 57 
Teeth, All-Porcelain Replaceable, 323, 
325 
Goslee, 329 
Tube, 329 
Teeth, Attachment to Supporting, 26 
Teeth and Facings, Cementing Replace- 
able, 453 
Insertion of Gold Fillings in Porce- 
lain, 435 
Teeth and Roots, Preparation of, 
7g 
Teeth Having Vital Pulps, Preparation 
of, for Attachments for Bridge- 
work, 100 
Teeth, Paralleling, Converging or 
Diverging, 85 
Teeth, Preparation for Full Shoulder 
Porcelain Crowns for Pulpless, 
95 
Preparation for Full Shoulder Por- 
celain Crowns for Teeth Having 
Pulps, 95 
Teeth, Selection of Abutment, 416 
Teeth, Separating Natural Crowns of, 
434 
Teeth, Soldering Gum Block, 63 
Telescope Crowns, 80, 460, 464 
Telescope Crowns, Gold, 117 
History of, 5 
Telescope Crowns, In Fixed Bridge- 
work, 294 
In Porcelain Bridgework, 353 
Partial, 302 
Telescope Crown Restorations, Remov- 
ing Full, 440 
Telescope Crowns, Sectional Method, 
119 
Telescope Crowns, With Peripheral 
Band, 81 
With Porcelain Facings, Gold, 158 
Telescoping Crown Attachments, Appli- 
cation of, 389 
Full, 373 
Telescoping Crowns, Full, 386 
Tempering, 32 
Temporary Attachments for Bridge- 
work, 312 
Temporary Dowel Crowns, 194 
Temporary Mounting, 465 
Tenacity of Metals, 31 
Therapeutic Requirements for Arti- 
ficial Crowns, 21 
Tissue, Artificial Restoration of Lost, 
401 
Traumatic Occlusion, 23, 250 
Treatment of Fractured Roots, 114 
Anterior Roots, 114 
Posterior Roots, 115 
Treatment of Perforated Roots, 113 
Tube Attachments, 372 
Application of, 387 
Tube Teeth, Use of, 332 
Unit Impression, 152 
Use of Soldered Facings and Swaged 
Cusps, 161 
Use of Vulcanite, 428 
Application of Lingual Bar to Vul- 
canite Saddles, 429 
Vertical Attachments, 370 
Application of, 378 
Vitreous Compounds, 74 
Vulcanite Restoration, 407 
Application of Lingual Bar, 429 
Vulcanite Saddles, 375, 407 
Vulcanite, Use of, 428 
Wax Patterns, 70, 71 
Webb Crown, History of, 9 
Welding, 32 
Weston Crown, History of, 8