' "f l _ -i . 'H '•&. 
. ‘ ■ ■ ■: :, • :• : : •■: 
. . . :■ Denial 
Stereoroentgenography 
By C. A. LE MASTER) D.D.S. 
PROFESSOR OF ROENTGENOLOGY 
St. Louis University Dental Department 
PUBLISHED BY 
THE SOUTHWORTH COMPANY 
Troy, N. Y., U. S. A. Copyright, 1923, by 
The Southworth 
Troy, N. Y. Dental Stereoroentgenography 
ByC. A. LE MASTER, D. D. S. 
Professor of Roentgenology, Saint Louis University Dental Department 
HE use of the stereoscopic method of 
roentgen technic in dental examinations 
is something new. It is something new 
| Ej| but not novel, for with simplified methods 
IP'S Jjafiw °f technic, it is of practical value. This 
method of examination has been grossly 
underestimated by some, and corres- 
pondingly exaggerated by others. The 
indisputable fact remains, that a simple 
roentgenogram is a flat record of superimposed shadows, 
while a stereoroentgenogram is a record of those same 
shadows arranged in their proper perspective planes, from 
which it follows that stereoroentgenography may be used 
with great advantage wherever the subject for examination 
calls for differentiation of structures lying in different 
planes and depths; we can, therefore, readily see that 
examinations of this character would be extremely 
valuable to the dental surgeon, whose technical work de- 
mands that he have a clear idea as to the relative positions 
of the teeth to their surrounding structures. 
€f| It is my hope that I may be able to give to the pro- 
fession a proof of the valuable aid which perspective adds 
to the dental roentgenogram. To do this it will be neces- DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
3 
sary to briefly review the fundamental principle involved 
in taking and viewing stereoroentgenograms; simplified 
methods necessary to obtain true stereoscopic plates of 
dental conditions, with both the intraoral and extraoral 
positions; the proper method of mounting and viewing 
them, and their value as compared with the flat roentgen- 
ogram. 
€J| The roentgenogram may be described as a record of 
shadows cast by objects which are placed between an X-ray 
tube in action and recorded on a sensitized plate or film. 
These shadows are recorded on the sensitized surface of 
the film in simple outline or sketch form and for that reason 
were at one time called a skiagram or outline. A roentgeno- 
gram, therefore, is a record of superimposed shadows one 
upon the other, which may not only render them difficult 
to interpret, but very often misleading. The density of 
these shadows is in direct ratio to the opacity or resistance 
which the objects offer to the passage of the roentgen ray, 
and it is often difficult to determine the position of these 
shadows when substances of different density are to be 
differentiated. 
€fj The stereoroentgenogram may be described as a 
record of shadows cast by objects which are placed 
between an X-ray tube in action and recorded on sensitized 
plates or films, two in number. One plate records the 
shadows cast when the central ray passes from the focal 
spot of the target of the X-ray tube at an angle corresponding 
to the angle of vision of one eye. The other plate records 
the shadows cast when the central ray passes from the focal 
spot of the target of the X-ray tube at an angle correspond- DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
4 
ing to the angle of vision of the other eye. We thus have re- 
cords of shadows from both angles of vision, and when they 
are viewed through a suitable apparatus, the stereoscope, the 
two roentgenograms fuse into one giving stereoscopic vision, 
enabling one to view artifically what our eyes would have 
seen if the object had been viewed directly. 
€JI Figure A illustrates the principle of making stereo- 
roentgenograms. 
<J1 This method of examination was first suggested by 
Ilihu Thompson in 1896, with reference to X-ray examina- 
tions. Sometime later Sir James Mackenzie Davidson of 
London, England, further developed this idea, and from 
that time on it has become a common practice with compe- 
tent roentgenologists all over the world. This is true with 
reference to the entire body except the teeth; very little 
work has been done by the dental roentgenologist on this 
phase of his work. 
€jj Singularly enough stereoroentgenography has been 
employed very little in its application to dental roentgeno- 
graphy. The extraoral stereos have been made for some 
time, but these, although valuable, do not give the informa- 
tion that intraoral stereos do for certain dental conditions. 
The failure of the dental roentgenologist to employ this 
means of examination may be summed up in the following 
manner: The technical difficulties encountered in placing 
the two films accurately in the same positions in the mouth 
for two exposures; in securing the absolute immobilization 
of the patient between exposures; in determining the 
proper angles of the central ray, with the two shifts of the 
X-ray tube; in properly mounting the roentgenograms for DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
5 DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
6 
viewing; and finally the actual difficulties experienced by 
some individuals in viewing stereoscopic films; all may be 
reasons for the less extensive use of this method of exami- 
nation. 
€[ It will be the purpose of this work to illustrate and in 
a general way give the technic required for making dental 
stereoroentgenograms and to prove the many benefits which 
the dentist may obtain from the judicious use of the princi- 
ple of perspective as applied to dental roentgeneology 
€J The technic for making dental stereoroentgenograms 
must be considered for both the intraoral and extraoral 
methods. Due to the fact that better detail and usually 
more satisfactory results can be obtained from the intraoral 
method, it is advisable to take as many of the teeth and 
areas of the process as possible this way. The areas which 
can be best taken with the intraoral method, film within the 
mouth, are as follows: The maxillary and mandibular 
anterior teeth; maxillary and mandibular cuspids and 
bicuspids. The molar regions are best taken with the 
extraoral method, the film outside the mouth. 
The technic necessary for the production of the intra- 
oral stereoroentgenogram has been the greatest difficulty in 
the past and it is mainly for that reason that this method of 
roentgenographing the teeth has been very little employed. 
There have been numerous film holders and appliances 
devised to aid in stereoscopic technic, but these in all 
instances have proven valueless. Many attempts have been 
made to secure true stereoroentgenograms within the mouth DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
7 
without practical results. The method which the writer 
advocates is simple and practical. To secure true stereo- 
roentgenograms and not those of the pseudo type has been 
the main difficulty. The dental surgeon will rely upon the 
stereos when operating and if they give him false information 
his results will likewise be false. Stereos that are to be 
used for such work therefore must be accurately made and 
mounted, otherwise they will prove misleading and worse 
than useless to the operator. 
€j[ Intraoral Technic. The technic may be described as 
follows and the steps mentioned must be closely followed 
to secure accurate results: 
*j| A. Prepare the tube shift with reference to the lateral 
shift, 2\ inches; tilt the tube by a special tilting device so 
that the direct rays are at both extremes pointing to a 
centre on the film. This is done at a given distance, say 
21 inches, and this distance must be used later when the 
exposures are made. The lateral shift of the tube corre- 
sponds to the pupular distance, and the tilt of the tube to 
the angle of accommodation which the eyes would use if 
viewing the object to be roentgenographed. Figure A 
illustrates the changes in position of the tube when taking 
stereorentgenograms. Position 1, first position. Position 
2, second position. 
<jj B. Prepare the films. The main requisite is a method 
whereby the films No. 1 and No. 2 may be placed relatively 
in the same positions in the mouth. Use either the Eastman 
large dental film No. 2 or if this is too large their special 
size No. 1 A, may be used. Take two film packets, 
marking them No. 1 and No. 2 respectively. Place film DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
8 
Kim. 1 
Film 2. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
9 
No. 1 between the maxillary and mandibular teeth as though 
an occlusial bite roentgenogram were to be made; instruct 
patient to bite on this film. With a pencil or pen trace the 
outline of occlusion of the maxillary anterior teeth from left 
to right cuspid, on their labial incisal aspect on the film. 
Figure B shows results of drawing on the film packet. It 
is difficult to trace on the parafin paper which covers the 
packets, but this difficulty can be overcome by pasting a 
sheet of white paper over the smooth surface of the cover. 
These can always be prepared in numbers of a dozen or 
more and are always ready for use. Transfer the sketch 
from film No. 1 to film No. 2. This is best done by tracing 
it off film No. 1 onto a thin piece of paper or celluloid and 
then using tracing paper to reproduce it on packet No. 2. 
Care must be taken to reproduce it on the same location 
on film No. 2 as it occupied on film No. 1. Mark packet 
No. 1 with a small lead UL” by placing it on a corner of 
the packet with a piece of adhesive tape. This film then 
will be for the left shift and will be the one for the left eye 
to view. To further insure that the stereoroentgenogram 
is later viewed properly, place a small piece of lead on the 
lingual aspect of one of the teeth, attaching it with adhesive; 
this will later show on the stereoroentgenogram and one will 
be able, knowing where the metal was placed, to determine 
whether it is being viewed from the labial, lingual or buccal 
aspect of the teeth, a very difficult and confusing matter. 
€J[ C. Clamp the patient’s head in the headrest so as to 
immobilize the part as much as possible. Instruct patient 
as to what is to be done; namely the opening and closing 
of the mouth, simply by dropping the mandible without DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
10 
moving the other part of the head; the placing of the films 
No. 1 and No. 2 into position; the shift of the tube, etc. 
€j| D. Replace film No. 1 between the teeth in its 
original position, using the sketch on the packet as a guide. 
Make exposure using regular technic; as a guide to the 
angle, namely, the angle of incident of the normal ray shall 
strike at right angle the plane which exactly bisects the 
angle formed between film and tooth, a law to which there 
is no exception. Remove film No. 1, insert film No. 2 
using the transferred sketch as a guide to position, shift 
and tilt tube to the other side and make the other exposure. 
The above method if followed accurately will give true 
stereoroentgenograms. 
<f[ If the maxillary or mandibular teeth are missing from 
the arch, it is not possible to use the above method. A 
thin aluminum tunnel can then be used, which will accom- 
modate the packets; this tunnel is placed in the mouth and 
the patient is instructed to bite upon it. The tunnel is slightly 
larger than the Eastman No. 2 dental film. It is possible 
with the use of this tunnel to place the films No. 1 and No. 
2 in accurately the same position within the mouth by using 
one side and corner of the tunnel as a guide to position. 
The same areas of the mouth can be taken with this method 
as the other, but the tunnel is rather large and causes con- 
siderable discomfort to the patient, and the first or sketch 
method, is usually the preferred one wherever it can be 
used. 
<H Extraoral Stereoroentgenographic Technic. The 
technic for making extraoral stereoroentgenograms does 
not differ from that used for other parts of the body, as DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
11 
they are taken with the plate or film on the outside of the 
mouth. This method is used when the maxillary or mandi- 
bular molors are desired, and also the maxillae and mandible 
themselves. The position of the patient may be described 
as follows: the affected side of the maxilla or mandible 
towards the plate. Care must be exercised to direct the 
central ray in such a manner as to project the shadows of 
the affected jaw without any superimposed shadows. A 
handy tunnel or shifting device for the film or plate is the 
following, designed by the writer, and one which meets the 
requirements for extraoral stereoroentgenograms. It is 
made to accommodate a 5x7 inch film or plate, taking both 
exposures on one film, which can then be viewed directly 
through a parlor hand stereoscope, this saves the trouble of 
mounting and makes the taking of them very simple. 
Figure C of the top of the tunnel will illustrate. The lead 
offers a protection for the part of the film unexposed and 
later, in the other position, for the exposed part. The 
entire top of the tunnel is covered with a one-quarter inch 
sheet of celluloid extending over the center of the tunnel, 
where the patient’s face is placed leaving this part of the 
film for the exposure. Bracket 1 illustrates the film in 
position for the first exposure, and bracket 2 illustrates the 
position of the film for exposure two. The tunnel should 
be mounted on a stand about four inches high and the ex- 
posures made with the patient in the prone position. Mark 
the left shift, and for convenience use position 1, marking 
that part of the film with the lead “L.” A small piece of 
lead placed on the outside of the cheek might also act as a 
guide to position of viewing later. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
12 DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
13 
<U The Stereoscope. The stereoscope is a simple opti- 
cal contrivance by which two flat roentgenograms of an 
object taken at different angles and from different view- 
points are viewed simultaneously and are fused into one 
image, giving the actual appearance of relief, showing the 
relative depths of the objects and their positions. 
<JI The sterescope was invented by Professor Wheatstone 
in 1838; subsequently Sir David Brewster invented the 
refracting or lenticular stereoscope. The stereoscope most 
practical for viewing the dental stereoroentgenogram is the 
small, hand, parlor stereoscope. 
<[j Mounting the Intraoral Stereoroentgenogram, 
Mounting the intraoral stereoroentgenogram is a very 
necessary and important step and care must be exercised to 
see that they are mounted accurately. The dental films 
have an emulsion side and a glossy or glazed surface, the 
glossy surface must be the one facing the observer. The 
stereoroentgenogram with the mark L must be for the left 
eye vision and the other one for the right eye vision. 
Mount them either upon a clear glass or better a sheet of 
frosted celluloid, using the lower border as a guide to 
position of mounting. This is best done by drawing a line 
across the lower border of the mount about one-half inch 
from the bottom, placing the lower border of the film 
directly upon this line. They are thus mounted parallel to 
one another. Place them about one-half inch from one 
another from the median line of the mount. Stereoroent- 
genogram No. 1 will illustrate this. If the positions of the 
films were accurately in the same positions in the mouth 
when the exposures were made, one will thus get the DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
14 
stereoscopic vision without any strain to the eye. If there 
i9 a strain this can usually be relieved by taking the stereo- 
roentgenograms off the mount, placing the glossy surface 
of one on the emulsion surface of the other, superimpose 
the shadows on the roentgenograms, and cut them both at 
their lower border so that you have a resulting straight line 
to use in placing them upon the mount. This should be 
sufficient to thus correct their faulty position and then 
should be viewed without strain to the eye. 
<[j Mounting the Extraoral Stereoroentgenogram. 
The extraoral stereoroentgenogram if taken with both 
exposures on the same film, does not have to be mounted, 
but can be viewed directly through the hand stereoscope. 
If they are taken on two separate films or plates, they are 
best viewed through the large stereoscope. If it is desired 
to view them through the small hand stereoscope they must 
be either reduced in size or it is possible to cut them down 
in size to show only a small area of the roentgenograms. 
This is done by superimposing and cutting them down the 
same as done to true up the intraoral ones. 
CJ] Viewing the Stereoroentgenograms. The intraoral 
stereoroentgenograms are viewed with the glossy surface of 
the films towards the observer, thus is obtained a view 
within the mouth out or from the lingual aspect of the 
teeth. The extraoral ones should be viewed the same way, 
and it is best to mark the sides of the films before develop- 
ing, indicating which side corresponds to the glossy surface 
and the emulsion surface. If plates are used, view through 
the glass side. If the areas X-rayed have been marked 
with a lead marker so that one is always able to determine DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
15 
whether he is viewing from the labial, lingual or buccal 
surface, they can then be viewed in any manner desired 
since it is always possible to determine which side is being 
viewed. A diffused light should always be used, it gives 
better detailed vision. It must be remembered that there are 
some individuals who find difficulty in accommodating their 
eyes for stereoscopic vision, while there are some who find 
it impossible to view stereoscopically. These individuals 
are comparatively few, however, and no one should place 
himself in this class until he has tried faithfully to accommo- 
date himself to stereoscopic vision. The observer will know 
when he is viewing stereoscopically, by the fact that the 
two roentogenograms fuse into one and give the appearance 
of depth to the view. To fully appreciate the stereoscopic 
effect, view and study the stereos in this work first without 
the stereoscope, then view stereoscopically and compare 
results. There are regulating devices on all stereoscopes 
and the settings differ for practically all individuals and 
must be regulated for all views. 
€J It is my desire to illustrate some of the valuable points 
in technic, and in order to do so clearly it is best to show 
some stereorontgenograms of dry specimens. The first 
few, therefore, will be of the dry specimen. 
<f| The usual question asked by the dentist doing general 
practice is “Of what value is the stereoroentgenogram to 
me? I do not attempt the difficult extractions such as 
impacted cuspids or third molars or the removal of foreign 
substances, etc.; I refer them to the men specializing in 
these particular branches.” Does he really know his 
limitations; does he not often attempt operations which are DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
16 
far beyond his ability, probably due to the fact that they 
appeared on the roentgenogram or flat picture to be very 
simple; and does he not after an attempt at operating on 
the case have to finally refer it to the specialist? Had he 
viewed the case stereoscopically he might have come to the 
conclusion that the case was not so simple as it had seemed, 
for the average person viewing the stereoroentgenogram 
says “Why you can see the condition plainly.” For ex- 
ample, if it is a case of an impacted or unerupted tooth 
which, from the flat roentgenogram appears to be in 
apposition to the roots of the other teeth, when viewed 
stereoscopically, however, it can be determined whether 
this condition is true or not and usually these unerupted 
teeth are not in apposition to the surrounding teeth; this 
the stereos will show. The real value therefore to the gen- 
eralpractitioner in dentistry is that it gives him a comprehen- 
sive view of the field of operation and thus makes him better 
able to diagnose the true conditions, enabling him to pro- 
ceed with an operation, where it is contemplated, with 
considerably more confidence and with a far greater hope 
of success, or enabling him to properly diagnose the case 
as one which is beyond his ability to operate upon. 
€H The Value of the Stereoroentgenogram to the 
Dentist Specializing in the Extraction of the Teeth. 
The exodontist of today is truly a surgeon and his duties 
are strictly surgical. True the roentgenogram is not abso- 
lutely necessary for every case he handles, but it is a valuable 
aid to him, especially where he is expected to remove the 
unerupted or impacted tooth or pieces of foreign substances. 
In cases of this kind he,like the medical surgeon, must first 
localize the foreign substance or tooth before operating, 17 
DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
since it is necessary to know its location with reference to 
the surrounding structures so that he may plan his operation 
and successfully perform it. The methods we have been 
using to localize such conditions in and around the teeth 
have proven unsuccessful. Although some very clever 
operations have been performed without the use of the 
stereoroentgenogram, I know that they could have been 
done with greater ease by the surgeon and with probably 
better results to the patient had he employed its aid, for 
with it he gets depth to his view and can really see the 
condition as it exists. 
€JJ The Value of the Stereoroentgenogram to the 
Orthodontist. The practice of orthodontia is a most scien- 
tific and exacting branch of the dental profession, and the 
Orthodontist, who really obtains results, is the one who 
carefully diagnoses his case and carefully plans his treat- 
ment; this is at times very difficult to do as many un- 
forseen things may come up during the treatment which 
are very discouraging. If he had had a clear understanding 
of, not only the relation of the erupted teeth, but also the 
unerupted ones with reference to their line of eruption, 
their position in the process with relation to the surround- 
ing teeth and structures, he could have been able to avoid 
many of these conditions. It will be easy to determine these 
conditions if one will study the stereoroentgenograms, for 
they surely afford an ideal study model of cases. 
<JI Bearing these facts in mind, a clear study of the 
stereoroentgenograms of this book should be evidence of 
the value of this method and show wherein its application 
could be of the greatest aid. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
18 
Anterior Maxillary Teeth Viewed from the 
Lingual Aspect. 
<{j Dry specimen. 
•K Illustrating the Dental Intraoral Stereoroentgenogram. 
<H Anterior maxillary teeth, viewed from the lingual 
aspect. 
<U Shows a cuspid on the right side decidedly to the 
lingual of the central and lateral incisors. The cuspid was 
glued to the hard palate opposite these teeth before the 
exposures were made. It is not in apposition to the teeth 
as the stereo shows. 
€[[ Note white shadow of the lead “L;” stereo for the left 
eye. Radiopaque object on the lingual surface of the 
central incisor, was attached to the tooth to act as a land- 
mark. It appears decidedly to the lingual of the tooth 
proving that you are viewing from the lingual aspect. 
€[[ Line shows position of mounting the stereos. 
[Stereo 1.] 
Stereo 1. 
Serial IN? 6 i DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
19 
Duplicate of Stereo 1 with the Roentgenogram for the 
Left Eye Placed on the Right Side and the 
Right Side on the Left. 
[Stereo 2.] 
Intraoral Stereo. 
Duplicate of Stereo 1 with the roentgenogram for 
the left eye placed on the right side and the right side on 
the left. 
<j[ It can be noted that the cuspid still appears on the 
right side opposite the right central and lateral incisors but 
this time labial to them; this reverses the appearance of the 
case; however, the shadow cast by the small piece of lead 
now appears on the labial surface of the left central incisor; 
knowing that this was placed on the lingual surface it 
immediately checks up as improperly mounted stereos. 
€[ It can easily be seen from this example the necessity 
of following the rules for, it is with difficulty, even with 
trained eyes to tell definitely whether one is viewing the 
lingual or labial aspect without some definite guide. 
Stereo 2 
Serial W 6 ; 20 
DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
Viewed from Buccal Surface, from Without 
the Mouth In. 
[Stereo 3.J 
€ff Dry specimen. 
<[ Illustrates the extraoral stereo. 
€[I Viewed from the buccal surface, from without the 
mouth in. 
Broken off hypodermic needle placed opposite the 
second mandibular molar on the buccal surface. 
€J[ Stereo shows the needle in position as described above 
€JI Lead marker was placed on the buccal surface of the 
crown of the second molar; which is seen between the 
viewer and the crown of the tooth; proving that you are 
viewing from the buccal surface. 
<J[ Both exposures made on the same film; size 5x7 
inches and viewed directly without mounting. 
Stereo 3. 
SerMV 67 DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
21 
Illustrates a Maxillary Cuspid Labial to the Righ: 
Central Incisor. 
[Stereo 4.] 
€[[ Dry specimen. 
•[ Intraoral stereo. 
€JI Illustrates a maxillary cuspid labial to the right centra 
incisor. 
€[ Cuspid was glued to place on the labial surface of the 
process opposite the central incisor before the stereos were 
made. 
<[ Lingual aspect view. 
Stereo 4. 
Serial ) 57 DklN l'AL S l'JEREORbfikTGENOGRAPHY—LE MASTER 
22 
Lingual Aspect View. 
€|[ Intraoral stereo. 
€[ Dry specimen. 
€[[ Lingual aspect view. 
<f| Localizes broken off hypodermic needle. 
<([ It appears distinctly lingual to the left maxillary cen- 
tral incisor, far removed from the root of the tooth. The 
needle was glued to place opposite the left central incisor 
before the exposures were made. 
Let it be remembered that the needle even if placed 
on the labial surface would appear lingual when viewed on 
the flat roentgenogram, for we are all trained from child- 
hood to associate clearness with nearness, and the needle 
being a very dense substance would appear just as clear in 
outline as it does on the lingual surface using identical 
exposures, for distance as a general rule plays little or no 
part in the roentgenogram when substances of heavy den- 
sity are to be localized. 
[Stereo 5.] 
Stereo 5. 
Serial 
A 9 67 DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
23 
Lingual Aspect View. 
[Stereo 6.] 
€|[ Intraoral. 
€f[ Dry specimen. 
*H Lingual aspect view. 
€[ Illustrates a broken off hypodermic needle opposite 
the left maxillary central and lateral incisors. It appears 
to be on the labial surface far removed from the crowns of 
the teeth. It was glued on the labial surface of these teeth. 
If these stereos are viewed without the stereoscope, as 
a flat roentgenogram, the needle appears lingual to these 
teeth. 
Serial 67 
Stereo 6. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
24 
Roentgenogram X 
<H Dry specimen. 
•B Occlusal bite roentgenogram. 
€|[ Skull has two unerupted teeth, maxillary cuspid on 
the right and bicuspid on the left. 
€[ Roentgenogram illustrates a method used to determine 
whether teeth are lingual or labial in their position. It is 
the only practical method which will show whether teeth 
are located lingual or labial to the teeth in the arch, other 
than stereos. The technic used in making this roentgeno- 
gram is simular to the one used to obtain the Sphenoid 
Sinus within the mouth; it is taken with the film between 
the teeth and is called the occlusal bite roentgenogram. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
25 
It shows the occlusal surface of the teeth and shows the two 
unerupted teeth as being lingual to the teeth in the arch; it 
does not give their long axis position in relation to the sur- 
rounding teeth or structures. 
€(] The exposure to obtain true occlusal roentgenograms 
of the maxillary teeth are as a rule prohibitive, as the ex- 
posure is necessarily very long, due to the fact that the 
central ray must pass through the thickest part of the skull. 
€J1 The illustration is shown so that a comparison can be 
made of the same case when the stereos are used. 26 
DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
Lingual Aspect View. 
[Stereo 7.] 
€J Intraoral stereo, 
f Dry specimen. 
€(I Lingual aspect view. 
€[| Same case as Roentgenogram X. 
Right maxillary cuspid; unerupted. It is seen to lie 
on the lingual surface of the right central and lateral 
incisors and bicuspids. Its cusp is directly opposite the 
apex of the central incisor, not in apposition to it. Lingual 
to the apex of the root of the lateral incisor, and superior 
and lingual to the bicuspid roots. Its root is deeply im- 
beded in thejprocess more so than the cusp of the tooth. 
The process was dissected from around this tooth and its 
position checked up accurately to that described above. 
Stereo 7. 
SeriaI\V 67 DENTAL STKKEUmENTGEfronOPHY—LE MASTER 
27 
Lingual Aspect View. 
[Stereo 8.] 
€[[ Intraoral stereo. 
<J| Dry specimen. 
€jj Lingual aspect view. 
Same case as Roentgenogram X. 
€J Localizes the left maxillary bicuspid; Its crown is 
lingual to the remaining root of the cuspid and its root is 
superior and 'lingual to the root of the first molar and is 
not in apposition to either of these roots. Also note that 
the apex of the unerupted bicuspid punctures and extends 
a slight distance beyond the periphery of the process on 
the buccal side. 
*H The process surrounding this tooth was dissected away 
and its position checked up accurately as described above. 
Stereo 8. 
Serial 
m. 67 28 
DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
Lingual Aspect View. 
<|1 Intraoral stereo. 
<jj Lingual aspect view. 
<JI Left maxillary central incisor. Unerupted; rotated with 
its labial surface towards the lingual. Note its line of 
eruption, it is erupting directly towards the viewer, lingual 
to the lateral incisor. The portion of root lingual to its 
crown was thought from the flat roentgenogram, to be that 
of a deciduous tooth; by studying the stereo carefully you 
can see that this is the root of the central itself and that it is 
a tooth having a decidedly curved root. It was realized 
after the stereo was made that this tooth would be valueless 
even if moved to its proper place in the arch and that it 
would be a difficult work if accomplished, so it was extracted 
and its position checked up very accurately with the above 
findings. This is certainly valuable to the orthodontist as 
it not only saved both he and the patient much incon- 
venience, but greatly assisted him in his diagnosis of the case. 
[Stereo 9.] 
Stereo 9. 
Serial X? t) < DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
29 
Lingual Aspect View. 
[Stereo 10] 
f Intraoral stereo. 
€[ Lingual aspect view. 
<[[ Left maxillary cuspid; unerupted. Stereo 11 will be 
the same case but the right side. If viewed without the 
stereoscope the tip of the cuspid appears to be lingual to 
the lateral incisor and will erupt lingual to this tooth. No 
indication of its position could be determined by digital 
examination. 
€(1 The stereo shows that it is erupting lingual to the 
lateral incisor. 
nfo . . 67 
Serial 
Stereo 10. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
30 
Lingual Aspect View. 
[Stereo 11.] 
<[[ Intraoral stereo. 
€fl Lingual aspect view. 
€f| Right maxillary cuspid; unerupted. Same case as 
Stereo 10. This cuspid also appears to be erupting 
lingual to the lateral incisor if viewed without the stereo- 
scope. The stereo shows it erupting labial to the lateral 
incisor slightly tilted toward the median line. No indication 
of its position could be determined by digital examination. 
This is surely valuable to the orthodontist, as it shows him 
where these teeth are located and their line of eruption can 
be seen. He will thus arrange his appliances when he 
starts the case to take care of these difficulties and obtain 
quicker and better results with less effort on his part and 
much less discomfort to his patient. 
Serial .• o 
Stereo 11. DENTAL-STEREOROENTGENOGRAPHY—LEMASTER 
31 
Lingual Aspect View. 
[Stereo 12.] 
€f[ Intraoral stereo. 
Lingual aspect view. 
€[[ Right maxillary cuspid and second bicuspid; unerupted. 
The cuspid can be seen to lie labial to the lateral incisor 
and misplaced slightly towards the median line. 
€[ The second bicuspid can be seen erupting slightly 
lingual and towards the distal, and is impacted against the 
crown of the first molar. Seeing these conditions the 
orthodontist can rearrange his appliance to take care of these 
teeth and thus obtain a uniform result, at the same time, 
instead of overcoming one difficulty at a time and always 
having new ones present themselves. Note that the stereo 
shows the relation of the appliance with the teeth and 
makes an ideal study model. 
Stereo 12. 
Serial DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
32 
Lingual Aspect View. 
[Stereo 13.] 
<|| Introral stereo. 
<f) Lingual aspect view. 
<jl To act as study model for the Orthodontist; there is 
indeed plenty to study in this case. 
<|j Supernumerary tooth can be noted erupted in the 
lateral incisor area; lateral incisor unerupted. Right max- 
illary cuspid unerupted; erupting in its proper position. 
<[ Supernumerary tooth superior to apex of the root of 
right maxillary central incisor; note that it lies inferior to 
the palatal ridge and is not deeply imbedded in the process; 
its root is lingual to apex of central incisor and will not be 
a difficult tooth to extract. 
<|[ This stereo is simply a general study model for the 
anterior teeth. Special ones were made for the cuspid and 
bicuspids on both sides to determine more accurately their 
position. 
Stereo 13. 
Serial^? DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
33 
Lingual Aspect View. 
[Stereo 14.] 
Intraoral stereo, 
€[j Lingual aspect view. 
<J1 Maxillary teeth. 
<j| Case taken to act as a study model for the Orthodon- 
tist. A study of this case reveals the condition, position 
and erupting plane of the unerupted teeth. This gives 
the Orthodontist a definite guide as to the proper method 
of treatment; it shows the relative position of the erupting 
teeth; it gives a comprehensive view of what he can expect 
of the case in the future. Surely this is valuable informa- 
tion. 
Stereo 14. 
Serial N9 34 
DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
Lingual Aspect View. 
€JJ Intraoral stereo. 
*}[ Lingual aspect view. 
€J Right maxillary cuspid; its position from the flat 
roentgenogram was described as follows: 
€|j It appears to lie lingual to the lateral incisor and first 
and second bicuspids, fairly high in the process. Attempt at 
extraction failed, for after dissecting the process on the 
lingual surface of these teeth and the tooth not reached, it was 
finally decided that the tooth was too high in the process 
to extract without a great deal of destructon of the process. 
<j| The stereo shows the position of the cusp of the cuspid 
to be labial to the lateral incisor root, its root to be 
lingual and superior to the bicuspids and molars, with the 
apex of its root within the antrum. An incision on the 
labial surface of the lateral incisor verified this position. 
This tooth can be easily removed by extracting the lateral 
incisor and thus you will have a direct line of extraction. 
[Stereo 15.] 
Stereo 15. 
Serial 67 35 
DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
Lingual Aspect View. 
[Stereo 16.] 
€Jj Intraoral stereo. 
€| Lingual aspect view. 
€J[ Right maxillary cuspid; Its position from the flat 
roentgenogram may be described as being lingual to the 
central and lateral incisors, bicuspids and molars. The 
stereo shows it to be lingual to the central and lateral incisors, 
with its crown nearly on a level with the apecies of these 
teeth making its position very high in the process. It is 
superior and slightly lingual to the bicuspids and superior 
to the molars with its apex apparently within the antrum. 
Due to the patient’s condition it was necessary to extract 
this tooth. After studying its position by means of the 
stereo it was removed with but little destruction of the pro- 
cess, from the buccal palate, superior to the molars and 
bicuspids. Its position checked up very accurately to that 
Stereo 16. 
Serial "N9 DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
36 
shown by the stereo. Suppose that its extraction would 
have been attempted from the lingual surface by dissecting 
the hard palate until the tooth could be reached, certainly 
a great amount of the process would have been destroyed, 
which would probably have been the procedure if the flat 
roentgenogram had been followed. From its position as 
shown by the stereos it might have been taken out through 
the nasal cavity, but it appears that the procedure followed 
was a good one as ideal results were obtained. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
37 
Lingual Aspect View. 
[Stereo 17.] 
*J[ Intraoral stereo. 
€}j Lingual aspect view. 
€JI Same case as Stereo 16, shows case immediately after 
the right maxillary cuspid was removed. 
€J| The vitality of the bicuspids was tested repeatedly and 
they tested as vital teeth, showing how thoroughly and 
efficiently the operation was performed. 
Serial N9 67 
Stereo 17. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
38 
Lingual Aspect View. 
[Stereo 18.] 
*fj Intraoral stereo. 
Lingual aspect view. 
€| Right maxillary central incisor; root remains in the 
process. A supernumerary tooth can be seen to lie superior 
and slightly lingual to the apex of this root. It can be 
removed through the socket left after extracting the root. 
Right lateral incisor; apex of root is considerably 
absorbed. 
<J| Left lateral incisor; large apical and lateral granulo- 
mata. 
€}} Note that the root of the lateral incisor is lingual to 
the root of the central incisor. Left central incisor appears 
to be involved in the granulomatous area of the lateral 
incisor. 
Stereo 18. 
Serial N9 fi 7 DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
39 
Lingual Aspect View. 
[Stereo 19.] 
iff Intraoral stereo, 
iff Lingual aspect view, 
iff Right mandibular cuspid; unerupted, 
iff Its position is slightly rotated so that its mesio-disto 
aspect is bucco-lingual. It is erupting buccal to the first 
bicuspid. Its line of eruption is clearly seen. This is par- 
ticularly valuable to the Orthodontist to know whether the 
tooth is erupting buccal or lingual to the erupted teeth. 
iff You can state positively when viewed stereoscopically 
that it is buccal but from the flat roentgenogram one would 
hesitate to definitely state. 
Serial X? 6 < 
Stereo 19. 40 
DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
Lingual Aspect View. 
[Stereo 20.] 
<IJ Introral stereo. 
•fl Lingual aspect view. 
*JJ Left maxillary cuspid; Its position when viewed 
stereoscopically may be described as follows: Crown is 
lingual to lateral incisor, is not in apposition to it, the root 
is buccal to apex of first bicuspids and superior and buccal 
to apex of second bicuspid. The cuspid is locked in 
between these teeth and unless carefully removed trouble 
will be experienced later with the bicuspids. This case is 
a beautiful example of the value of perspective to the 
Exodontist. This tooth was extracted without difficulty, 
and first bicuspid was extracted first, then cuspid. No 
injury was done to second bicuspid. It tested later as a 
normal, vital tooth. 
Stereo 20. 
Serial 67 DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
41 
Lingual Aspect View. 
[Stereo 21.] 
€ff Intraoral stereo. 
€| Lingual aspect view. 
<{| Right maxillary cuspid; unerputed, showing its posi- 
tion to be decidedly labial to the lateral incisor and buccal 
to the first bicuspid. 
€}] The root of the lateral incisor has been moved towards 
the lingual. Extraction of the cuspid is necessary. 
Serial N? 67 
Stereo 21, DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
42 
Lingual Aspect View. 
[Stereo 22.] 
€j| Extraoral stereo. 
Lingual aspect view. 
€J! Left mandibular third molar; It is not impacted but 
is erupting lingual to the second molar. It was extracted 
without the use of the elevator as it was not in apposition to 
the second molar, and by simply removing the soft tissue 
over the occlusal surface of the crown it was easily grasped 
with the forceps and removed with very little difficulty. 
This method surely aids the Exodontist in localizing the 
molar, which is the first step when extraction of such a 
tooth is contemplated. 
Stereo 22. 
Serial IN? 67 DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
43 
Lingual Aspect View. 
[Stereo 23.] 
€|| Extraoral stereo. 
€J| Lingual aspect view. 
tj[ Left maxillary third molar; unerupted, erupting de- 
cidedly lingual to the second molar. Could this be defi- 
nitely stated from the flat roentgenogram? You could not 
with definiteness state whether it is lingual or labial to the 
second molar. With the aid of the stereo it can be defi- 
nitely stated that it is lingual. We thus eliminate guess 
work. 
Stereo 23. 
Serial N9 fi? DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
44 
Buccal Aspect View. 
[Stereo 24.] 
€Jj Extraoral stereo. 
€}| Buccal aspect view. 
*j| Left mandible; Advanced destruction of the mandi- 
ble with partial destruction of the body and angle. The 
angle itself is partially destroyed, and a line of fracture can 
be noted running along the mesial side of the unerupted 
third molar; this is a pathlogical fracture without separa- 
tion of the fragments which the stereo shows. Numerous 
sequestra are formed and a large one can be seen inferior 
to the roots of the third molar. 
€}| The stereo is valuable in as much as it gives a compre- 
hensive view of the condition as well as showing that there 
is no displacement of the fragments. 
Serial "N9 67 
Stereo 24. DENTAL STEREOROENTGENOGRAPHY—LE MASTER 
45 
1 ingual Aspect View. 
[Stereo 25.] 
€jj Intraoral stereo. 
€j| Lingual aspect view. 
€| A cyst involving the hard palate on the left side. 
<U The root of the left lateral incisor appears necrotic. 
The left cuspid is involved and forms the distal wall of the 
cyst. The stereo shows that there is a communication with 
the nasal cavity; a valuable point due to the fact that the 
mucous lining of the nasal cavity and the periostium was 
still in contact and if extensive curretment was performed 
in this area a puncture might have resulted with a drainage 
into the nose. Principle point of drainage was posterior 
to the lateral incisor. No evidence of a communication or 
involvement of the maxillary sinus can be noted. 
€JI Without the stereo the depth of the destruction cannot 
be followed. 
Stereo 25. 
Serial N? 67