Columbia Winibtvsiit? in tiie Citp of j^eto porfe ^tfjool ot Bental anb (J^ral ^urgerp l^eference ^itirarp 1/" ^ Digitized by the Internet Archive in 2010 with funding from Open Knowledge Commons http://www.archive.org/details/interpretationofOOivyr INTERPRETATION OF DENTAL AND MAXILLARY ROENTGENOGRAMS INTERPRETATION OF DENTAL AND MAXILLAEY . ROENTGENOGRAMS BY ROBERT H. IVY, M.D., D.D.S. MAJOR, MEDICAL RESERVE CORPS, UNITED STATES ARMY; ASSOCIATE SURGEOX, COLUMBIA HOSPITAL, MILWAUKEE; FORMERLY INSTRUCTOR IN ORAL SURGERY, UNIVERSITY OF PENNSYLVANIA. ^V1TII 259 ILLUSTRATIONS ST. LOUIS C. V. I\[OSBY COMPANY 1918 Copyright, 1918, By C. V. Mosby Company Press of C. V. Mosby Coinlmiiy St. Louis TO MY UNCLE MATTHEW H. CRYER, M.D., D.D.S. PREFACE Tlie purpose of this small volume is to present to iiiem- bers of the medical and dental professions the data neces- sar}^ for making an intelligent diagnosis of pathologic conditions about the teeth and jaw bones in which roent- gen examination plays a part. It is hoped that a basis for this will be formed by study and comparison of the numerous normal and al^normal views sho^^^l. It has been said that the actual making of the roent- genogram is the elementary feature of roentgenology, and that those who know how to interpret roentgeno- grams are few in number compared with those who know how to make them. It is to interpretation rather than to technic that the writer has endeavored to call par- ticular attention in the following pages, references to technic being limited to special points involved in ex- amination of the teeth and jaw bones, A departure from the usual method of presentation lies in the fact that in this work the roentgenograms are negative reproductions ; i. e., they correspond with the original negatives in that bone and hard tissues are light, and soft tissues and spaces are dark, instead of being merely prints of the negatives, in which the dark and light portions arc reversed; so that in studying these illustrations there is a near approach to natural condi- tions found in the original negatives. In a majority of the odontograms showing periapical pathology, the writer has been in a position to compare the pictures with the conditions found at operation, so that in these cases the interpretations are not based mer<'ly upon surmise. The writer desires to thank Dr. j\r. H. Cryer for per- 9 10 PEEPACE mission to use the excellent anatomic illustrations taken from his Internal Anatomy of the Face, and also his associates, Drs. P. B. Wright and M. PI. Mortonson, for cooperation and help in the preparation of roentgeno- grams. Acknowledgment is also due the publishers for their patience in waiting for the manuscript, Avhich was con- siderably delayed owing to the exigencies of military service. EoBEET H. Ivy. Milwaukee, Wis. CONTENTS PART I PAGE CHAPTER I General Considerations 17 CHAPTER II Anatomy of the Teeth and Jaws, avit]i Special Reference to Roentgenogram Interpretation 24 CHAPTER III Pathology in Relation to Dental Roentgenology 36 CHAPTER IV Correlation of Clinical Findings with Roentgenographic Exam- ination 49 CHAPTER V Roentgenographic Findings About the Teeth and Jaavs in Their Relation to Prognosis and Treatment 62 CHAPTER VI Stereoscopic and Other Methods op Localization 67 PART II CHAPTER VII Interpretation 77 11 ILLUSTEATIONS FIG. TAGE 1. Showing cancellated lioue of alveolar process 25 2. Anterior view of skull, showing anterior opening of nasal cliamber 2(i 3. Showing thickness of bone between the apices of the molar roots and the maxillary sinuses 27 4. Showing smooth prominence in floor of maxillary sinus .... 27 .5. Showing floor of maxillary sinus dipping down between roots of molar tooth 2S fi. Showing maxillary sinus not extending much anterior to the first molar 2S 7. Maxillary sinus extending in front as far as the region of the first premolar tooth 29 8. Showing anterior palatine fossa just behind and between tlu> upper central incisor teeth 30 9. Showing cancellated internal structure of mandible with mental foramen below and between roots of premolar teeth .... 31 10. Plate of right side of face, with head placed especially to show molar region . . ^ 32 11. Diagrammatic illustration of Fig. 10 33 12. Plate of left side of face, showing normal anatomic landmarks and impacted upper third molar 34 13. Diagrammatic illustration of Fig. 12 35 14. Inflammatory periapical tissue of the more acute type 39 15. Chronic type of periapical inflammation 39 16. Case of long-standing inflammation 41 17. Mass of squamous epithelial cells .• ^-'^ IS. Early stage of cyst formation 43 19. High power view of epithelial cyst lining 43 20. Later stage of cyst formation 44 21. Faradic battery used to test pulp vitality 50 22-^. Diagram of teeth with faradic I'oaction, etc., indicated .... 54 22-B. Plate of left side 54 22-C. Plate of right side 55 22-D and E. Films of upper left teeth 55 22-i^ and G. Films of upper right teeth 55 23. Eisen plate rest attached to stand for taking head plates . . . 5(i 24. Position of head and angle for left side of jaws 57 25. Position for exposing intraoral dental films 58 26. Diagram showing position f(M' ex]iiising sinus plate, ami projec- tion of the sinuses i.n llie plate 5i) 13 14 ILLUSTRATIOjSTS FIG. PAGE 27. Opacity due to empyema of left maxillary sinus 60 28. Position and angle of tube for iirst expjosure in plate stereogram cf the jaws 68 29. Diagram giving the angles of the tube in making stereograms of the jaws and teeth 68 .30. Position and angle of tube for second exposure in plate stereogram of the jaws 69 31. Stereogram showing unerujated impacted upper third molar lying to lingual side of arch 71 32. Central position of the tube prior to making stereoscopic film exposures 73 33. Position of tube for exposure of first film in making dental stereo- gram 73 34. Position of tube for exposure of second film in making stereogram 74 35. Method of mounting stereoscopic films so that they may be adjusted to desired p)Ositions 75 36. Hand stereoscope 75 37. Diagrammatic illustration of localization 76 38-85. Eoentgenograms of upper anterior region , 79-90 86-117. Roentgenograms of upper right region 91-98 118-161. Roentgenograms of upper left region 99-109 162-175. Roentgenograms of lower front region 110-113 176-189. Roentgenograms of lower right region . . . . . . 113-116 190-205. Roentgenograms of lower left region 117-120 206-217. Roentgenograms illustrating the use of the x-ray as a check on root canal treatment , . 121-125 218-219. Roentgenograms illustrating the use of the x-ray as a check on surgical treatment 126 220-225. Views of impacted canines, no attempt at localization . .127 226-229. Localization of impacted canine 128-129 230-237. Roentgenogram showing impacted molars 130-134 238. Roentgenogi'am of supposedly edentulous patient 81 years of age 134 239. Large area of bone destruction in left angle and ramus of man- dible 135 240. Roentgenogram of same case as Fig. 239 taken four months later 135 241. Cyst of right side of upper jaw 136 242. Roentgenogram showing extensive bone destruction of lower jaw due to acute osteomyelitis 136 243. Large area of bone destruction on right side of mandible . . . 137 244. Large infected cyst on right side of mandible due to infection about roots of first molar 137 245. Calcified composite odontoma of right side of mandible in an adult 138 246. Calcified composite odontoma of lower jaw 138 247. Calcified composite odontoma iji a boy ten years of age .... 138 248. Periapical bone destruction connected with lower left second molai' 139 ILLUSTEATIOTvTS 15 >'IG. PAGE 24^). Retained piece of root of lower left first molar 139 250. Root of upper right first molar lost in maxilhiry sinus durino- attempted extraction 140 251. Root of upi^er right first molar lost in maxillary sinus during attempted extraction 140 252. Roentgenogram of right side, showing laclv of development of teeth 141 253. Same ease as in Fig. 252, showing similar condition on left side . 141 254. Fracture of left side of mandible just in front of second molar . 142 255. Fracture of left side of ma]idil)le in second premolar region . . 142 256. Fracture of left side of mandible near canine tooth 143 257. Fracture through neck of mandilile 143 258. Double fracture of mandible in molar region ou each side . . . 144 250. Same case as in Fig. 258, showing swaged metal intermaxillary splint in position 144 INTERPRETATION OF DENTAL AND MAXILLARY ROENTGENOGRAMS PART I CHAPTER I GENERAL CONSIDERATIONS Tlie application of the roentgen ray as a means of diagnosis of pathologic conditions about the teeth and jaws is a method that has achieved a x>osition of the utmost importance in recent years. Its value has long been recognized by the surgeon in the diagnosis of the grosser surgical lesions of the maxillary bones, such as fractures, tumors, impacted teeth, etc. Until re- centty, however, the dentist in general practice rarely found it necessar}^ to resort to investigation by means of the x-ray. At the present time, to those who are familiar with its advantages, the daily employment of this agent as a means of diagnosis and as an aid to proper treatment has become indispensable. It is not my purpose here to deal with the knowledge necessary for the making of roentgenograms, involv- ing as this does a study of electricity, theory of produc- tion of x-rays, a description of x-ray machines and tubes, etc. What is of far more importance to the average dental or medical practitioner is to know how to interpret roentgenograms after they are made. Mis- takes are frequently made by tliose having an inadequate knowledge of the primary essentials which will presently be discussed. 17 18 INTERPRETATION OF ROENTGENOGRAMS At this point an explanation of certain terms to be used in the book is in order. In speaking of x-ray pic- tures many different terms are employed, such as roent- genogram, skiagraph, skiagram, radiograph, etc. The American Koentgen Ray Societ}^, which may be properly taken as the official representative of this branch of med- ical science in the United States, has adopted in honor of Roentgen, the discoverer, a nomenclature which I con- sider it advisable to follow. Thus, in speaking of an x-ray picture the term "roentgenogram" is to be pre- ferred. "Roentgenology" is preferable to "radiology." Certain other words have been coined for the sake of brevit,y, such as "stereogram," meaning a stereoscopic roentgenogram; "pyelogram," a roentgenogram of the pelvis of the kidney after injection with some salt that resists passage of the rays. In the same way the term "odontogram" is here suggested for a roentgenogram depicting the teeth. Since the general recognition of the imx)ortant rela- tionship of infections of the investing tissues of the teeth to various pathologic conditions of the body, an examination for the detection of the cause or portal of entry of many generalized infections may be justly re- garded as incomplete without a thorough investigation of the teeth and surrounding parts. Since serious peri- apical dental infection may be present in the entire ab- sence of subjective or objective symptoms or history of trouble, every examination of this tyioe should include a roentgenographic study of all crowned and pulpless teeth, and parts of the alveolar process from which teeth are apparently missing. The necessary cooperation be- tween physician and dentist in eliminating possible foci of infection within the mouth can only be achieved through an ability on the part of each to intelligently interpret roentgen ray findings. The lack of dental knowledge on the part of the johysician usually leads to unnecessary sacrifice of teeth, while the dentist's igno- GENERAL CONSIDEEATIOlSrS 19 ranee of proper roentgen ra^^ interpretation often means ultraconservatism with consequent danger to the health of the patient. The importance of thorough study of this subject is manifested by the occurrence of cases which baffle even those of great experience in all phases of dental diagnosis, including the roentgen ray. There is no intention here to intimate that every den- tist should be equipped with an x-ray outfit and make his o\^m roentgenograms. Most men have not the time to devote in which they can acquire a mastery of the sub- ject. In the average individual practice there is not sufficient variety to give one experience in interpretation. At the same time, dentistry can not be intelligently or conscientiously practiced without convenient access to this method of diagnosis at least in all cases Avhere root canal operations are involved. Where the dentist him- self does not make the roentgenogram, the burden of in- terpretation should not fall entirely upon the roentgen- ologist, who is usually without knowledge of the clinical conditions of the individual case or of dental pathology in general. Unless he has had experience in this work the dentist should not attempt to read the roentgenogram without help, even though he be entirely familiar with the clinical aspects of the case. In the following pages it is endeavored to point out the essentials necessary for correctly diagnosing patho- logic conditions about the teeth with the roentgen ray as an aid. That the roentgen ray is merely an aid in arriving at this diagnosis can not be too strongly empha- sized, and, therefore, a proper interpretation of a roent- genogram can, as a rule, only be given after one has gained a knowledge of certain general facts, as Avell as special data pertaining to individual cases in question. The general knowledge necessary for the correct in- terpretation of odontograms comprises the foUoAving : 1. The normal anatomy and histology of the teeth and jaw bones, together with anatomic variations. 20 INTEKPEETATIOlsr OF EOEiSTTGEK^OGRAMS 2. The appearance that the roentgen ray should impart to plates and films after passage through such normal tissues and anatomic variations. 3. Special dental pathology both from the clinical side and the histopathologic side. After mastering these three essentials, one is in a posi- tion to take up — 4. The various abnormalities produced in the roent- genogram by disease. The four points mentioned will be discussed more in detail in subsequent chapters. After acquiring a thor- ough familiarity with them, it is hoped that the student will be in a position, with the aid of the special clinical facts pertaining to the individual case, to make use of the valuable assistance afforded by a'oentgenographic examination. Limitations of Roentgenography The longer one is engaged in this work, the more con- servative and less positive he becomes in giving an opin- ion as to what is represented in a given plate or film. He begins to see the error and folly of calling every dark spot at the end of a tooth root an ''abscess," which in reality is found less commonly than some other abnormal conditions. Like everything new, the roentgen examina- tion of the teeth has been overworked, and very extrava- gant claims have been made. Based upon roentgenologic interpretation by workers ignorant of dental conditions, or of the clinical facts in individual cases, physicians have ordered the wholesale extraction of absolutely healthy teeth. The failure to obtain improvement of systemic complications in such cases, in which the teeth never had any bearing on the question at all, has produced a reac- tion on the part of some men, who question the value of dental roentgen diagnosis entirely, an opinion that is hailed with joy by some nonprogressive or ultraconserva- GENERAL CONSIDERATIONS 21 tive dentists who dislike anything that is likely to force a change in their obsolete methods of practice. The time has come, however, when those working in this field are in a position to state with some assurance how far the roentgen ray may be relied upon. We must start out with the general proposition that what we see in a roentgenogram is only a varied gradation of shadow cast by the rays passing through substances of different density. Speaking strictly, therefore, Ave can only say in regard to dark areas on the negative that they represent places of lessened density, which allow the rays to pass through more easily than the surrounding parts. This is as far as a person untrained in the fundamental prin- ciples mentioned is justified in giving an opinion. What the actual contents of the rarefied areas are, we can sel- dom say definitely from the roentgenogram alone, al- though along with the clinical findings and history we can often predict with some assurance as to what will be found at operation. Even in the absence of s^miptoms, a periapical rarefied area as shown in the odontogram does mean usually that disease of some kind is present, unless the picture has been made shortly after operation before the area has had time to become obliterated. The state- ment has been frequently made by some eminent authori- ties that these areas of rarefaction shown by the roent- gen ray are noninfective in the absence of pain and local symptoms, and may simply represent the results of pve- viously existing disease that has been cured, in other words, that they contain harmless scar tissue. While conceding this possibility in a small number of cases, I believe that the persistence of such a rarefied area for any length of time without signs of decreasing in size is sufficient evidence that a disease process is going on, otherwise the area would gradually become smaller and be replaced by new bone. There is abundant postojDera- tive x-ray evidence that these areas of rarefaction disap- 22 INTERPEETATIOISr OF ROENTGENOGRAMS pear and are replaced by new bone unless infection re- mains. Operative and postoperative pathologic findings so strongly support the view that these rarefied areas as shown by the roentgen ray are active foci of disease in most cases, that in our opinion it is the wisest course to regard them as diseased until proved healthy, especially in invalids, as it is a much more serious matter to leave a potential source of systemic infection than to eradicate a possibly healthy area. We sometimes hear the following statement made by the undul}^ conservative skeptic after he has extracted or has had extracted teeth shown by the roentgen ray to be responsible for periapical bone destruction : ' ^ I examined the teeth carefully after they were out, and there was nothing wrong with them." In other words, he at- tempts to convey the impression that owing to mistaken roentgen diagnosis the teeth were unnecessarily sacri- ficed, basing his opinion on a casual superficial inspec- tion of the teeth alone, when the real seat of the disease was located, not in the tooth itself, but in the surrounding alveolar process. A postoperative opinion, to be of any value, should be based on what is found by proper curette- ment of the rarefied bone about the apices of the ex- tracted teeth, including perhaps bacteriologic and his- tologic study of the tissue removed. Because there is no visible absorption or exostosis of the root, no fluid pus, or no so-called '' abscess sac" adherent to the root when it is extracted, this does not necessarily mean that no disease is present in the surrounding bone. While we can never say absolutely from the odonto- gram what constitutes the contents of these rarefied peri- apical bone areas, yet a study of the picture often reveals points that enable us to make at least a tentative diag- nosis. Thus, a round or oval area of bone rarefaction with very sharply defined regular edges, and which per- mits practically complete passage of the rays, is fairly GElsrEEAL CONSIDERATIOlirS 23 good evidence that a cyst is present. On the other hand, an area with ill-defined edges, merging almost imj)ercep- tibly with the surrounding healthy bone, and in most of its parts offering at least some resistance of the passage of the rays, is indicative of the presence of a more or less active suppurative process. Between these two extremes we find various gradations, among which may be placed cases of granuloma. The size of an area of suspected abnormality has no relation to its character or jDatho- genicity. Disease may be present without pus. Absence of an abnormal roentgenographic area does not necessa- rily mean that the tissue must be healthy. A tooth may contain infected necrotic pulp tissue, giving rise to sys- temic involvement, yet show no evidence of bone rare- faction in the odontogram. A sinus discharging pus may be present, yet there may be insufficient periapical bone rarefaction or destruction to be demonstrable by the roentgen ray. We frequently find at operation condi- tions much worse than depicted in the odontogram, so that the latter often underestimates and seldom exag- gerates the amount of disease present. Localization Eoentgenograms as ordinarily made do not give any perspective, and it is generally impossible in such pic- tures to determine the relative positions of given parts of the objects shown except in two dimensions. We have two means of gaining a better idea of the relative posi- tions of objects hidden from view by the tissues, such as roots of teeth, etc. The simplest is by making two or more odontograms in different positions, and comparing the different pictures. The other method is by stereo- roentgenography; i. e., making two views with the plate or film and the object in the same relative positions, but with the rays at different angles, perspective being gained by merging the two images in the stereoscope. These two methods will be described in another chapter. CHAPTEE II ANATOMY OF THE TEETH AND JAWS, WITH SPECIAL REFERENCE TO ROENTGENOGRAM INTERPRETATION In the passage of the roentgen ra3^s through the tis- sues, the denser the tissue the greater the obstruction offered to the rays, and consequent!}' the lighter will be the image in the negative. In roentgenograms of the jaws, the substances depicted in the order of their density, beginning with the densest, and therefore the lightest in the negative, are: 1. Metallic crowns and fillings, and root canal fillings containing zinc or other metals. 2. Enamel of the teeth. 3. Dentine. 4. Cementum. 5. Cortical bone. • ^ 6. Cancellated bone. 7. Medullar}^ spaces, canals, foramina in bone, and soft tissues. In disease, the normal condition of a given tissue may be changed either to a lessening in densitj^, meaning abstraction of lime salts, with consequent deepening of the shadow in the x-ray negative, or an increase in den- sity, due to a deposit of lime salts, and indicated by a lessening of the shadow. A familiarity with the anatomy of the teeth and jaw bones is one of the fundamental essentials for correct interpretation of odontograms. Lack of this knowledge is frequently a cause of mistaking of normal shadows for manifestations of disease. 24 ANATO:\IY OF THE TEETH AXD JAWS 25 The tooth are set in sockets in the alveohir jDrocess, being attached by the peridental membrane. The alveolar process is composed of spongy or cancellated bone (Fig. 1), which appears in the roentgenogram as a fine inter- lacing network. The sockets of the teeth are lined with a thin plate of dense bone, which is shown in the x-ray -,.00^ .m\ V-- #N IN J *• '^ ■■■■■"• , ,«»<-.•■" Fig. 1. — Showing cancellated bone of alveolar process. (Cryer.) negative as a fine white line around the tooth. Between this line and the tooth itself is a narrow dark space rep- resenting the peridental membrane. These lines are im- portant landmarks in the interpretation of odontograms, as their absence or deviation vsuaUi/ means some patho- logic condition. (See Fig. 39, p. 79.) 26 INTERPRETATION OF ROENTGENOGRAMS Roentgenographic Anatomic Landmarks in the Upper and Lower Jaws Upper Jaw At a varying distance above tlie apices of the central and lateral incisor teeth is fonnd the iloor of the nose (Fig. 2), sometimes seen in the odontogram as a dark Fig. 2. — Anterior view of skull, showing anterior opening of nasal chamber. (Cryer.) shadow which might be mistaken for a cj^stic or abscess cavity in the bone (Figs. 47 and 48, p. 81). Above the apices of the premolar and molar teeth is found the maxillary sinus or antrum of Highmore. This sinus varies very much in its extent, shape, and in the relation of its floor to the roots of the teeth. Sometimes there is a considerable thickness of bone between the tooth apices and the sinus (Fig. 3). In other cases the tooth ANATOMY OF THE TEETH AND JAWS 27 apices come right up to the floor of the sinus, even form- ing projections into the cavity, though under normal con- ditions always separated from it by a thin lamina of bone (Fig. 4). Sometimes the ends of the roots are found well Fig. 3. — Showing considerable thickness of bone between the apices of the molar roots and the mamillary sinuses. (Cryer.) Fig. 4. — Showing smooth prominences in floor of maxillary sinus overlying apices of roots of premolar and molar teeth. (Cryer.) above the most dependent portion of the sinus, but lo- cated in its wall (Fig. 5). The floor of the maxillary sinus is usually found in relation to the roots of the molar INTERPRETATIOlSr OF EOENTGENOGRAMS 1 11 bt molai 1 1 -^t molai Fig. S. — Showing floor of maxillary sinus dipping down between roots of molar tooth, the apices thus being above the level of the floor. (Cryer. ) Infraorbital sinus Infraorbital foramen d passing through infraorbital canal and foramen. Maxillary sinus. Opening caused by apical abscess. Fig. 6. — In this specimen the maxillary sinus does not extend much anterior to the first molar. (Cryer.) ANATOMY OF THE TEETH AITD JAWS 29 teeth (Fig. 6), but ma}^ extend as far forward as the first premolar or canine (Fig. 7). These varying rela- tions of the floor of the antrum of Highmore to the roots of the teeth are well shown in x-ray negatives, the cavity of the antrum appearing as a dark shadow wliicli must I'ig. 7. — Here the floor of the maxillary sinus extends in front as far as the region of the first premolar tooth. (Cryer.) not be mistaken for a rarefied disease area. It is some- times difficult in the study of odontograms of this region to determine whether or not the roots of the teeth project into the maxillary sinus and whether areas of absorption about the roots communicate with it. In the odontogram, dU INTERPEETATION' 01^ EOE:N"TGE]SrOGRAMS where a root is projected above the level of the floor of the antrum, it is important to seek carefully the dark and light lines found around normal teeth in order to dif- ferentiate the normal condition shown in Figs. 5, 87, and 89, p. 91, from pathologic conditions in which roots com- municate with the cavit}^ of the sinus. FoRAMiivrA, Caitals, Etc. — In the upper jaw, on tlie Fig. 8. — Showing anterior palatine fossa just behind and between the upper central incisor teeth. The posterior palatine canal is seen as a groove running parallel to and just within the line of the molar teeth. (Cryer.) palatal surface just behind and between the central in- cisor teeth is found the anterior palatine fossa (Fig. 8). This contains foramina carrying blood vessels and nerves from the nose. In roentgenographic films of the anterior teeth this fossa is frequently seen as a dark shadow above and between the apices of the central incisors, and when A]SrATOMY OF THE TEETH AXD JAAVS 61 in close relation to roots of teeth under suspicion, miglit be mistaken for rarefaction due to disease of the bone (Fig. 41, p. 79). The posterior palatine canal (Fig. 8), is found in the form of a groove running posteroanteriorh' in the roof of the mouth mesially to the molar teeth. In the roent- genographie film it is occasionally shown as a dark Fig. 9. — Showing cancellated internal stiaicture of mandible with mental foramen be- low and lietween roots of premolar teeth. (Cryer.) shadow in the wall of the antrum in close relation to the palatal roots of the molar teeth. Lower Jaw Here the iDrincipal roentgenograiDhic anatomic land- marks are the mandibular canal and the mental foramen (Fig. 9). The mandibular canal runs posteroanteriorly below the apices of the teeth, and sometimes in very close relationshix) with them. (Fig. 10.) In the roentgeno- gram the root of a lower molar may apparently project into the dark space representing tlie canal, yet in reality be situated to one side or the other. 32 IlvFTERPEETATION OF EOENTGENOGRAMS The mental foramen, situated below and between the lower premolar teeth, may easily be mistaken for an area of disease associated with one of these teeth, par- Fig. 10. — Plate of right side of face, with head placed especially to show molar region. Horizontal impaction of lower third molar. (See Fig. 11.) Mandibular canal seen below this tooth. ticularly if there are clinical signs giving a suspicion of trouble (Fig. 176, p. 113). Very frequently, however, the connection of the mental foramen with the inferior dental canal can easily be seen in the roentgenogram (Fig. 182, p. 115). In hlms of the upper premolar and molar region the ANATOMY OF THE TEETH AXD JAWS 66 overhanging malar bone frequently casts a shadow which obscures the roots of these teeth (Figs. 127 and 128, p. 101). Fig-. 11. — iTtiagrammatic illustratioi) ■' i j; 10. a. Portion of iower jaw overlapped by shadow of opposite side; b, vertebiv. >. maxillary sinus and nasa' lossa; d, ;i>gion of ethmoid cells; e, mandilnilar ca;.al; r, liyoiical inflammation, preponderance of fibrous tissue. showing fewer cells and Fig. 17. — Mass of squamous epithelial cells (debris epitheliaux paradentaircs) bedded in chronic periapical inflammatory tissue. 42 INTEEPEETATIOISr OF EOENTGENOGRAMS thus depriving the latter of its blood supply, and con- verting it into a necrotic foreign body. Coincident with the chronic abscess or granuloma for- mation, rarefaction and absorption of the necrotic cemen- tum of the root apex takes place by the action of endo- thelial leucocytes and foreign-body giant cells. This is usually accompanied by the production of new cementum by cementoblasts that have not been destroyed, forming irregular thickenings of the root. Sometimes this hyper- cementosis is the principal lesion found. The contents of the spaces produced hy periapical bone absorption, including bacteria and their products, have direct connection ivith the general circulation through capillary blood vessels and lymphatics in the ivalls of the cavities and running in all directions through the granu- lation tissue. While the outer layers of the granuloma may be denser and more fibrous than its inner portion, there is no limiting membrane in the sense of preventing its contents from entering the general circulation. After eradication of infection in a periapical bone area, new bone is usually formed, filling in the space after sev- eral months. The space at first contains blood clot, which, if sterile, organizes into fibrous connective tissue. Then the bone cells of the surrounding alveolar process deposit lime salts, the density gradually increasing until normal bone is the result. Occasionally this new bone is much denser than normal, due to excessive deposit of lime salts, and is shown in the odontogram as a light area. This dense bone, by pressure on sensory nerve filaments, may cause neuralgia. Cyst Formation Among the connective tissue elements of the inflamma- tory granuloma developing as a result of infection about the root apex are frequently found masses of squamous epithelial cells (Fig. 17). Similar cells are present nor- PATHOLOGY AIS^D DENTAL ROENTGENOLOGY 43 Via 18. — Early stage of cyst formation, showing- cavity lined with several layers of epithelium, with chronic inflammatory tissue at the periphery. Fig. 19. — High power view of epithelial cyst lining. 44 interpeetatioisj' of eoentgenogeams iiially in the peridental membrane, where they are known as debris epitJieliaux paradentaires of Malassez. These epithelial cells are believed to be remains of the outer cells of the enamel organ which originally passed down and formed the outer wall of the sac in which the cemen- tum of the root was formed. Proliferation of these epithelial cells found among the granulation tissue is stimulated by the chronic inflammatory process. The Fig. 20. — Later stage of cyst formation, showing pressure atrophy of epithelial lining. mass of epithelium then breaks down in the center, it is believed by fatty degeneration, and a space is formed containing fluid (Figs. 18 and 19). This cyst cavity grad- ually enlarges, the pressure of the fluid causing atrophy of the epithelial cells, until the wall of the cyst consists of a dense fibrous capsule lined with at most a few layers of epithelial cells (Fig. 20). All traces of epithelium may finally disappear. The cyst fluid is usually clear, straw- PATHOLOGY AND DE]SrTAL EOENTGE]S!'OLOGY 45 colored, and may contain cliolesterin crystals, recognized by their rectangular shape with a notch in one angle. The fluid is generally sterile, but infection of the cyst wall may convert it into pus from which various organisms may be recovered. Dental root cysts may vary con- siderably in size, from that of a small pea to a hen's egg (Figs. 217 and 243). In the maxilla, they may invade the maxillary sinus or the nasal fossa (Fig. 241). Cyst for- mation, contrary to the opinion of some authors (Thoma), is common in connection with periapical infection.* Stages of Periapical Disease in Relation to Roentgeno- graphic Abnormalities The principal stages of chronic periapical disease giv- ing rise to roentgenographic abnormalities may be summed up as follows: 1. Chronic Proliferative Pericementitis, producing a slight thickening of the peridental membrane aliout the tooth apex, but without appreciable loss of bone. In the odontogram this is shown by an increase in thickness of the normal dark line between the apical portion of the tooth root and the bone. 2. Chronic Karefying Osteitis with Granuloma. — A slow disintegration of bone takes place in a circum- scribed area about the tooth apex, the bone tissue being replaced by granulation tissue. The tooth apex may project into the bone cavity, may be shortened or rough- ened from irregular absorption of the cementum, or may present enlargements due to hypercementosis. In the roentgenogram these lesions are shown as more or less clearly defined areas of lessened density; i. e., darker than *For a more detailed description of the histopathology of chronic periapical dis- ease with a complete review of the literature of the subject, the reader is referred to the article by Henrici and Hartzell in the Journal of the National Dental Associa- tion, 1917, iv, 1061. 46 INTERPRETATIOlSr OF EOEiSTTGENOGRAMS the surroundiiLg bone. The irregular form of the apical end of the tooth root is also shown when present. 3. Cheo^^ic Rarefying Osteitis witpi SuppuRATioisr. — '■ Here we have an area of bone destruction in which the space is entirely or j)artly filled with fluid pus. The apical peridental membrane is nearly always destroyed, the root end roughened, with the necrotic cementum bathed in pus. The infection in this type of lesion is to be regarded as more active than in the preceding form. The roentgenogram presents a blurred area of somewhat lessened density compared with the surrounding bone, with irregular and ill-defined margins, into which the roughened tooth apex projects. The more active the suppurative process, the more irregular and ill-defined will be the margins of the lesion in the odontogram. 4. Cheoi^ic Rareeyixg Osteitis with Cyst Foematioi^. — This stage succeeds that of granuloma, the cavity in the bone being filled with clear fluid and often little soft tis- sue except a thin fibrous sac. In the roentgenogram, therefore, the cyst appears as a very clearly defined dark area involving the apices of one or more teeth. The margins are regular and very sharply defined, so that there is usually no difficulty in telling exactly where the health}^ bone ends. The basis for the foregoing classification consists in roentgenographic examinations checked up by subse- quent extraction of teeth or surgical treatment followed by histologic and bacteriologic examination. Infection of the Investing Tissues of the Teeth Beginning" at the Gingival Margin — Pyorrhea Alveolaris For a detailed discussion of the etiology and pathology of chronic suppurative pericementitis or pyorrhea alveo- laris the reader is referred to Black's ''Special Dental Pathology," and other works. Only such points will be PATHOLOGY AXD DEISTTAL EOEXTGEXOLOGY 47 taken up here as have a direct bearing upon roentgen diagnosis. This disease always begins as a gingivitis due to irri- tation of the gum about the necks of the teeth. Among these irritating factors may be mentioned: malocclusion, involving misapplied stress in mastication; improper con- tact of teeth produced by faulty restorative operations, permitting the wedging of food between the teeth with im- pingement upon the gum septum; imperfect margins of crowns and fillings, either pressing upon the gum tissue or permitting lodgment of food ; lack of cleanliness, allow- ing deposition of calculus and food. Any of these causes will produce a local injury to the gum tissue, and permit infection by the microorganisms always present in the mouth. Various constitutional diseases, by lowering vital resistance are predisposing factors. At first the lesion is confined to the gum tissue (gingivitis), giving rise to no roentgenographic changes. Later, the peridental mem- brane is attacked (chronic gingivopericementitis), the in- fection progressing slowly from the gum margin toward the apex of the tooth. In the roentgenogram at this stage we may see a thickening of the normal peridental dark line. Very soon after involvement of the pericementum, the bone becomes affected (osteopericementitis),this being first manifested in the odontogram by absence of the apex of the bony septum between the teeth. The bone surround- ing the tooth is now progressively destroyed toward the apex, and the entire bony support of the tooth may be lost. Sometimes sufficient bone remains in the apical region to give the tooth a good deal of firmness, and it is surprising- how little bone ma}' be indicated in the odontogram for this to be the case. In the roentgenogram the loss of bone is shown by a lessening in density which in advanced cases may completely surround the tooth. As the bony support is destroyed, the tooth may incline from its nor- mal axis, particularly if an adjoining tooth has been lost. 48 INTERPRETATION OF ROENTGENOGRAMS Deposits of calculus upon the root and absorption and irregularities of the cementum are also shown. In molar teeth, chronic suppurative pericementitis may be shown in the odontogram as a dark area of absorption at the bi- furcation of the roots. Roentgenographic study of cases of chronic suppura- tive pericementitis is of importance in order to determine the extent of bone destruction in deciding the line of treatment to be followed. It is also of value in showing new bone formation in the course of treatment of a case. CHAPTER IV CORRELATION OF CLINICAL FINDINGS WITH ROENTGENOGRAPHIC EXAMINATION Errors in diagnosis of tooth conditions are frequently observed owing to lack of coordination of the clinical, roentgenologic, and other parts of the examination. The roentgen examination is frequently made and the findings reported independently of or entirely without a clinical examination of the mouth, and vice versa. On account of this, important pathologic conditions are sometimes overlooked ; or, on the other hand, undue significance may be attached to the findings of either examination. False interpretation of dental films by roentgenologists is not infrequent. On the other hand, cases are often seen in which clinical examination alone, without the roentgen ray, failed to reveal serious lesions that were present. In order that these errors ma^^ be avoided as far as pos- sible, a definite routine should be followed preliminary to making the roentgen examination, particularly where a complete examination of the teeth and surrounding- parts is desired, in the detection of any possible foci of mouth infection. Routine Examination First of all, the person upon whom the interpretation of the roentgenograms devolves, should know as much as possible of the history of individual teeth of the patient, in regard to previous treatment, abscesses, swellings, pain, etc. A knowledge of particulars of this kind may vitally modify the interpretation. A general survey of the mouth and associated parts should be made. In this way \\w cxainiuci- (^])tains a 49 50 INTEEPEETATION OF ROENTGENOGRAMS clue as to the nature and extent of the roentgenologic ex- amination required. The presence of pyorrhea, ulcera- tions, suppurating sinuses, swellings, etc., is noted. Electric Test. — The next important step consists in determining and noting down on a chart, so far as pos- sible the condition of each tooth in regard to vitality of the pulp, which teeth are crowned, and which are miss- ing. The most convenient and reliable method of deter- mining pulp vitality is by means of the faradic battery, shown in Fig. 21. This batter}^ contains one dry cell. The negative electrode is held in the hand of the patient. Fig. 21. — Faradic battery used to test pulp vitality. The positive pole consists of a pointed dental exploring instrument mounted on an insulated handle. The point is wrapped with a wisp of cotton and dipped in water. Starting at the median line of the upper jaw, each tooth presenting an enamel surface is touched in turn with the moistened electrode, and the result noted as minus, plus or doubtful. Crowned teeth are marked ''C, " and miss- ing teeth ''M." This chart then forms the basis for the roentgen examination, which is to be applied to all places in the mouth showing negatively responding, crowned, or missing teeth. The teeth with vital pulps can usually CORRELATIOlSr OF CLINICAL FliSTDIXGS 51 be ignored, as tliey are practicalh^ never the seat of hid- den apical disease. Of course, it may frequently be nec- essary to subject teeth with vital pulps to roentgen ex- amination to show the amount of bone destruction due to pyorrhea. The faradic test is not absolutely infallible in determining the vitality of the pulp, but it is the best means that we have at present. A false negative result may be obtained sometimes in teeth with recession of the pulp and formation of secondary dentine, while a false positive response may be due to the presence of large metallic fillings conveying the current to the gum or to contiguous vital pulps. For this reason also, the current is not relia])le in determining the vitality of pulps be- neath shell crowns. In such cases it may be necessary to remove the crown and then apply the test. A nervous patient, too, may imagine he feels a response in a pulpless tooth after receiving several shocks in succession through vital pulps. The foregoing steps in the mouth examination are to be regarded as preliminary or leading up to the roentgeno- graphic examination. Without them as a guide we should be forced either to pick out certain suspected areas for roentgenographic study, thus many times overlooking far more important conditions, or, as is done by many roentgenologists, make films showing ever}^ tooth in the mouth, which is obviously a waste of time and material, and also frequently incomplete. We endeavor to overcome the defects of the usual methods of examination by the following plan: First of all a plate (5x7 inches) is made of each side, taking in all the teeth of the upper and lower jaws from the canines backward, and also shoAving the region of the angle and ramus. This gives a general survey of the mouth, discounting any preconceived ideas as to condi- tions expected to be found. Unsuspected abnormalities are in this way frequently discovered, Avhich would be 52 INTERPRET ATIOi!^ OF ROEiSTTGEISTOGRAMS . overlooked if only certain areas or even the usual loca- tions of teeth were covered with films ; in addition to this, pathologic conditions about lower premolars and molars are generally more satisfactorily shown in plates than in films. Omng to trismus, it ma}^ he impossible to place a film mthin the mouth. After exposing the plates, each smgle area comprising teeth either crowned or negative to the electric current, or considered to require more de- tailed study than is shown in the plate, and any area in the front part of either jaw from which teeth are missing, is covered Avith a small film. The film picture shows the opposite aspect of that which is shown in the plate, this being due to the fact that the plate is extraoral, and the film intraoral. B}^ following this routine, we have been rewarded man}- times by the detection of unerupted teeth, especially third molars, cysts, odontomas, roots in the maxillary sinus, diseased maxillary sinuses, etc., which might easily have been overlooked had films been depended upon alone. One of the fundamental princi]3les of a general physical exam- ination is the importance of surve3^ing the body as a whole. In the same way, in this special field, we should examine the entire mouth, not blindly, but in an intel- ligent manner, instead of selecting suspected areas here and there with films. Of course, as a guide in the treat- ment of individual teeth, a film exposure usually is sufficient. Record of Examii^ation" Fig. 22 shows the record of a specimen case. At the top is a chart of the teeth, with the results of the f aradic test; crowned and missing teeth are also marked. Below are shown the plates of the two sides, with films covering the pulpless and crowned teeth in the upper jaw. For the lower teeth the plates alone usually are sufficient. In this case our interpretation should read about as follows : Upper Right. — Central incisor crowned, imperfect COREELATION" OF CLI]SriCAL FIJiTDIl^GS 53 root filling-, periapical rarefying osteitis with suppura- tion, and absorption of root; there is also a perforation of side of root; first premolar, devitalized pulp, no root fill- ing, periapical rarefying osteitis with granuloma; this area extends to the periapical region of the second pre- molar, previously extracted; first and second molars pulp- less, partial root fillings, periapical regions normal. Upper Left. — Central incisor crowned, partial root filling, small area of periapical rarefying osteitis with granuloma ; lateral incisor pulpless, good root filling, peri- dental thickening about apex; canine pulpless, good root filling, apex normal; first premolar crowned, imperfect root fillings, slight peridental thickening about apices; second premolar crowned, partial root filling, small area of periapical rarefying osteitis with granuloma; first molar has been jDreviously extracted, and at this point is a large area of bone destruction, probably with cyst formation. Lower Right. — Second premolar pulpless, partial root filling, periapical region normal ; second and third molars crowned, partial root fillings, periapical rarefying oste- itis, probably with granulomas, about the teeth. Lower Left. — Second molar crowned, partial root fill- ings, periapical region apparently normal; the croA^^l on this tooth has an overhanging edge, permitting the collection of food and debris. Positions Used in Exposixg Plates axd Films While this book is primarily intended to throw light on the interpretation of dental and maxillary roentgeno- grams, it is not considered out of place to briefly describe the positions used by the writer in exposing the plates and films. Most operators in making roentgenograms of the head and teeth place the patient in the recumbent position, which entails considerable preparation and discomfort. 54 INTERPEETATIO]Sr OF ROENTGENOGRAMS According to the following technic the work is done with the patient in a sitting posture on a chair facing the stand. A stand of a well-known make is employed. To r-A - C I' c c amOOOJUUmO/JDoa "^f" RQRQl^mW ■* J LV JV V C C />^— -r+--r+ "^-^ -5- -V- 4- H C N\ Fig. 22-A. Fig. 22-B. /I. — Diagram of teeth, with faradic reaction, etc., indicated. B.— Plate of left side. it is added a standard head clamp, and a plate rest specially designed by the late Dr. E. J. Eisen. The CORRELATION OF CLINICAL FINDINGS 55 Fig. 22.-C. Fig. 22-D. Fig. 22-E. Fig. 22-R Fig. 22. Fig. 22-G. C— Plate of right side. ^ D and B. — Films of upper left teelh. F and G. — Films of upper right teeth. 56 INTERPRET ATIOlsr OF ROENTGENOGRAMS plate rest is fixed at an angle of 15 degrees do\\Tiward from the horizontal, and is placed 19 inches from the target. The tube holder and funnel are drawn out to the full length of the horizontal arm of the stand, and tipped inwardly at an angle of 30 degrees from the vertical (Fig. 23). A 5x7 inch plate with the emulsion side up is placed on the plate rest. The patient is now seated somewhat to the right or left of the stand with the head laid on the Fig. 23. — Eisen plate rest attached to stand for taking head plates. plate in such a position that the focal ray will pass through the mastoid process of the uppermost side of the head (Fig. 24). This position brings the uppermost side of the mandible in as nearly a perpendicular position as possible to the plate, thus minimizing overlapping of the two sides. If canine and premolar regions are particu- larly desired, the patient's nose should be pressed against the plate, while for molars the nose should be slightly CORRELATION OF CLIXICAL FI]S'DINGS 57 raised from the plate. The head clamp is now tightened, and the exposure made. For intraoral films, the angle of the tube holder is re- versed as shown in Fig. 25, the patient's head being sup- ported by an ordinary head rest attached to the back of the chair. As a rule, no sort of film holder other than the patient's thumb or finger is necessary, though occasion- ally the cork devised by Dr. M. L. Rhein is of advantage. The film fits into a slot cut in the cork and bv this means Fig. 24. — Position of head and angle for left side of jaws. is held between the patient's teeth. The emulsion side of the film is always placed against the teeth to be taken. Modifications of these routine positions must, of course, be made to suit individual cases. Where symptoms sug- gest the possibility of disease of the nasal accessory sinuses, or where it is suspected that dental infection in- volves the maxillary sinus, roentgenographic examina- tion of these parts is often of value. This is carried out by using the technic described by "Waters and Waldron (American Journal of Roenfgenologi/, February, 1915), 00 II^TERPEETATIOiSr OF ROENTGEjSTOGEAMS for which this stand is well adapted. An 8x10 inch plate is used, at 22 inches from the target. The patient is seated directly in front of the stand, — if a woman, with all hairpins removed — and the head placed on the ]3late rest with the chin touching the plate and the nose not quite touching. The tube holder is tipped until the base of the funnel is parallel with the plate, and the focal ray directed toward the root of the nose. (Fig. 26.) By Fig. 25. — Position for exposing intraoral dental films. means of a plate of this kind the two sides of the face can be compared and empyema of the antrum of Highmore or of the other sinuses detected by increased opacity to the rays as compared with the healthy side. It is seldom possible from a plate or film showing conditions only on one side to detect the presence of pus in the antrum, but by the addition of the sinus plate just described, the diag- nosis may often be completed. Fig. 27 shows opacity of COREELATIOiSr OF CLIjSTICAL FINDINGS 59 tlie left maxillary sinus, due to empyema. Still further information may be obtained when necessary by making- lateral or vertical views of the sinuses. Identification of Given Plates and Films with the Sides and Parts of the Mouth to Which They Belong Provided that plates and films have been made ac- cording to the technic described, how is one who has not Fig. 26. — Diagram showing position for exposing sinus plate, and projection of tlie sinuses on the plate. witnessed the examination to determine which teeth are depicted in a given plate or film? Plates. — In exposing a plate, it is recalled that the side of the face to be slioAvn is laid against the emulsion 60 IjSTTEEPPvETATIOX of EOENTGEiSrOGPiAMS surface and the rays directed from the opposite side of the head. Therefore, a finished plate of the riglit side, with the emulsion surface toward the observer, should look toward the left, while a plate of the Jeff side should look toward the right. Films. — In making a film, it is placed in the mouth with the emulsion surface toward the inner or lingual aspect of the teeth, and the rays directed from the same side of the head. A finished film should be viewed with Fig. 27. — Opacity due to empyema of left maxillary sinus. the shiny surface toward the observer. In the case of the anterior teeth, the uppers and lowers are distin- guished by their size and shape. The teeth on the right side will be to the right of the film, and the left to the left. Films of upper posterior teeth are frequently dis- tinguished by showing outlines of the maxillary sinus, while in lower films, the occlusal line of the teeth is generally concave, and the mandibular canal and mental foramen may be slioA\m. The upper and lower molars are CORRELATION OF CLINICAL FUsTDINGS 61 also disting'nislied by the number of their roots. With an upper fihn held with the roots of the teeth pointing- upward, and a lower film with the roots pointing down, shin}^ side of film toward the observer, the hindermost teeth of a film of the right side will be toward the riglit of the film, and the hindermost teeth of a film of the left side will be to the left of the film. This explanation is difficult to give in words, but after a little practice the recognition of the part of the mouth to which a film be- longs becomes automatic. In the illustrations shown throughout the book, the rules just given have been followed. CHAPTER V ROENTGENOGEAPHIC FINDINGS ABOUT THE TEETH AND JAWS IN THEIR RELATION TO PROGNOSIS AND TREATMENT The physician is frequently called upon to decide or give advice on the question of saving or removing teeth which have caused or are associated with given patho- logic conditions as revealed by the roentgen ray. While each case must be considered individually, yet it is pos- sible to lay down certain rules for general guidance. Like all generalities, they are subject to exceptions and modifications. The diagnosis of periapical pathologic conditions about the teeth depends upon the history, the symptoms, the clinical examination, and the roentgen examination. AVhen these have resulted in a diagnosis, one of three methods of treatment so far as the tooth is concerned, is to be considered; namely, (1) conservative treatment; (2) surgical removal of the diseased condition by resec- tion of the root with curettement of the diseased bone area; and (3) extraction of the tooth followed by curette- ment of the diseased bone area. Many times teeth are condemned for extraction which could be safely retained by proper treatment, owing to lack of discrimination on the part of the physician. On the other hand, the training of the average dentist does not permit him to grasp the broad pathologic aspect of the question, with the result that he may often attempt conservation of teeth which may be a danger to the life of the patient, and labor under the mistaken belief that 62 PEOGNOSTS AND TREATMENT 63 he lias by inadequate treatment freed teeth from infec- tion when in reality the}^ still remain a menace. Until dentists become more familiar with diseased con- ditions of the body in general, the responsibility in this matter in jiatients suffering- from systemic infection w^ith foci in the mouth should lie with the physician, and this necessarily requires on his part a familiarity with roent- genographic interpretation of these dental conditions. In the formation of an opinion as to whether conservative or operative treatment should be carried out, the question of the training of the dentist for this particular work must be considered. Unless the dentist is familiar with modern methods of aseptic root canal work, and is guided and checked in his operations by the roentgen ray, by far the safest procedure is the immediate extraction of any tooth in which the pulp chamber is entered by decay, whether or not periapical infection be demonstrated. If the patient is in the hands of a competent dentist, with a sense of surgical asepsis, and familiar with modern accessories that have been found by the best workers to be essential, much can be accomplished in the saving of many teeth that show distinct evidence of extension of infection to the periapical region. The question of conservative or radical treatment of teeth showing periapical involvement should first of all be decided by the general health of the patient. Our at- titude toward treatment of suspected diseased teeth in patients who have some systemic condition in which mouth infection is possibly playing a part should be much more radical than that adopted in patients having no physical ailments. Many times a tooth may be passed along for treatment in a healthy individual where in an invalid a tooth so affected would be removed without hesitation. So far, no reliable or satisfactory preopera- tive pathologic means of proving the connection between suspected peridental areas and systemic conditions has 64 INTERPEETATIOlSr OF EOElSrTGEjSrOGEAMS been discovered, so at present we must take the risk of occasionally sacrificing- a harmless tooth, which is a small matter when weighed in the balance against the general health of the individual. Periapically diseased teeth, as shown b}^ the roentgen ray and other means of examination fall into two general groups so far as treatment is concerned: (1) those which should unquestionably be extracted under all conditions, and (2) those in which more conservative treatment may be attempted. 1. In the first group fall teeth showing the following conditions : (A) Large periapical areas of chronic rarefying oste- itis in which one-third or more of the peridental mem- brane has been lost and in which the cementum is eroded and absorbed. (B) Teeth in which the side of the root has been per- forated and infection of the lateral peridental membrane with bone destruction has occurred. (G) All upper molars and all lower teeth with extensive IDeriapical areas of chronic rarefying osteitis with granu- loma, suppuration, or cyst formation, or even compara- tively small areas in which the x-ray reveals root rough- ening or absorption, because the locations of these teeth are not as a rule favorable for root resection. Teeth falling in Classes A, B, and C should be unhesi- tatingly extracted regardless of whether tlie patient is otherwise healthy or not. 2. In the second group are found teeth in which in otherwise healthy individuals an effort at conservation may be attempted by measures directed toward opening, draining, and sterilizing root canals and periapical areas, followed by root canal filling, and in some cases finally completed by root resection. Such teeth, with appro- priate treatment indicated, may be classified as follows : (D) Teeth showing peridental thickening in the apical PROGNOSIS AND TREATMENT 65 region, due to chronic jDroliferative pericementitis may be treated by opening, draining, sterilizing, and filling root canals after negative culture, followed by periodical roentgen examinations. (E) Teeth showing small areas of periapical bone de- struction with granuloma may be treated as in Class D, followed by apical root resection and curettement, in the case of upper incisors, canines, and premolars, and extrac- tion when located in other parts of the mouth, if examina- tion three months later shows no reduction or oblitera- tion of periapical area, (F) Upper incisors, canines, and premolars, with larger periapical areas of granuloma, suppuration or cyst for- mation, with or without roughening and absorption of apical cementum, and even smaller areas associated with the latter condition should be treated by the usual root canal opening, sterilization, and filling, and immediate apical root resection and curettement followed by extrac- tion if at the end of three months the x-ray reveals no attempt at bone regeneration in the area involved. Teeth falling in Classes E and F, and occasionally also in Class D should be extracted without attempts at con- servative treatment in cases in which they are believed to be the cause of systemic infection. Chronic Suppurative Pericementitis or Pyorrhea As regards the treatment of teeth involved in this con- dition, the following general rules may be followed: Teeth where the surrounding bone destruction is so great as to deprive the tooth of over one-third of its sup- port, should be extracted. Multirooted teeth in which the bone destruction and granulation tissue have extended to the bifurcation of the roots, should be extracted. Teeth in which suppuration from pyorrheal pockets 66 INTERPRETATION OF ROENTGENOGRAMS resists persistent attempts at conservative treatment or treatment by gum amputation, should be extracted. It is felt that physicians advising and dental surgeons carrying out treatment in accordance with the general rules outlined above, in the majority of cases, will be open to criticism neither for iiltraconservatism on the one hand, nor for undue radicalism on the other, but will be following a sane middle course. CHAPTER VI STEREOSCOPIC AND OTHER METHODS OF LOCALIZATION Roentgenograms, as ordinarily made, are flat pictures; i. e., they do not give any perspective, and it is impos- sible in such a picture to determine the relative joositions of given parts except in two dimensions. In the majority of dental conditions in which the roentgen ray is an aid in diagnosis, the simple flat odontograms give all necessary information; but occasionally one meets with a case in which other methods are called into use with advantage. In the case of an unerupted canine, for instance, it is im- possible to determine from a single film whether the un- erupted tooth lies on the labial or the palatal aspect of the other teeth, and clinical signs of its position are often lacking. We have two means of gaining a more accurate knowl- edge of the relative positions of different objects in the roentgenogram: (1) stereoscopic method; (2) by making- two or more odontograms in different positions, and com- paring the several pictures. Stereoroentgenography In the case of an unerupted impacted tooth, a foreign body, or a fracture, the information obtained from a stereoscopic view is often of inestimable value, tlie method yielding as it does a picture of almost equal clear- ness and perspective as would be obtained by actual visual examination through the hard tissues involved. In making stereograms of the teeth and jaws either plates or films are employed, according to the location 67 bo IlSTTEEPEETATIOl^J" OF EOEITTGEl^rOGEAMS and extent of the area involved. For showing conditions about individual teeth, especially in the front of the mouth, films may be used, while plates are' more suitable in cases involving the posterior part of the mouth, such Fig. 28. — Position and angle of tube for first exposure in plate stereogram of the jaws. Fig. 29. — Diagram giving the angles of the tube in making stereograms of the jaws and teeth. as impacted third molars, or where a considerable area is to be examined, as in the case of fractures, embedded bullets, etc. Technic The technic of plate stereograms will be described first. The operation involves making tAvo exposures Avith the METHODS OF LOCALIZATION 69 tube in different positions. The first exposure is made with the same position of tube and patient as for a single plate described on p. 56. (Figs. 28 and 29-A.) The patient is instructed to keep the head in exactly the same position for the two exposures, as any movement will interfere with the stereoscopic effect. Care must also be taken to place the second plate in exactly the same posi- tion as the first, which is easily accomplished by means Fig. 30. — Position and angle of tube for second e.xposure in plate stereogram of the jaws. of lines ruled on the plate rest or by means of a special slot arrangement in the plate rest into which the plates can be slipped. The first plate having been slid out from under the patient's head and the second plate placed in the same position, the tube is shifted three inches in to- ward the upright stand. In order for the central ray to strike the second plate at the same point as in the first, it becomes necessary to change the aneie of the funnel 70 INTERPRETATION^ OF ROENTGENOGRAMS from 30 degrees to 17^ degrees from the vertical (Figs. 30 and 29-B). The second exposure is now made, exactly the same time being given as in the first exposure. After development, the plates may, of course, be vieAved through the large Wheatstone stereoscope. If this instrument is not available, lantern slides or prints can be made from corresponding parts of the two plates, and viewed very satisfactorily through the ordinary hand stereoscope. In viewing these plates through the stereoscope, it must be remembered that they must be placed sideways, owing to the direction in which the tube Avas shifted between the exposures. In mounting the lantern slides for the stereoscope a cover-glass is made by washing the emulsion off an old 5x7 inch plate, cutting it down to 4x7 inch, and fastening the slides to this with paper or cloth binding strips. Fig. 31 illustrates the value of stereoscopic roentgenography in locating an unerupted impacted upper third molar. There were no signs to indicate the position of this tooth by ordinary examination. Ordinarily such a tooth would be assumed to lie disto-huccally in relation to the second molar, and a single x-ray plate would only confirm this assumption. Stereoscopic plates, however, showed that the third molar lay on the disto-palatal aspect of the second molar. The operative incision was made at this point, the tooth readily found, and laceration of the buccal side of the gum was avoided. In making intraoral films stereoscopically, the most im- portant points to be observed are that the patient's head and the film must maintain the same position for the two exposures. The angles for the tube holder are based on a working distance of sixteen inches from target to film. The plate rest is first removed from the stand. The tube holder is then tipped sidewise at an angle to suit the indi- vidual case in the plane at right angles to the dental arch of the patient. In the plane parallel to the dental arch. METHODS OF LOCALIZATION 71 i o MS C.2 H^ ■>'o 72 INTEEPEETATION OF ROENTGENOGRAMS the funnel is in a vertical position. (Fig. 32.) The pa- tient is now seated in the chair, with the head supported by the head rest in such a position from the end of the funnel that with the film in the mouth against the teeth to be studied there will be approximately a distance of six- teen inches from target to film. The position should also be adjusted to avoid distortion as much as possible. This ' ' centering ' ' having been accomplished, the tube is placed in position for the first exposure by moving it one and one- half inches to the left of the central point, and tipping it inward at an angle of 7% degrees from the vertical plane. This will bring the focal ray to the same spot on the film as with the tube in the central position (Figs. 33 and 29-Z)). After the first exposure has been made, the second film is quickly inserted in the same position in the mouth as the first, care being taken not to move the patient 's head. The tube is now shifted three inches to the right and tipped at an angle of 7^ degrees from the vertical in the opposite direction from that of the first exposure, so that the central ray will again converge at the same spot on the film (Figs. 34 and 29-C). In viewing films through the stereoscope the difficulty in mounting them so that identical objects in the two films will fuse readily is overcome by the following plan : a piece of glass is cut from an old 5x7 inch plate to a suitable size to fit the stereoscope •(4x7 inches). To this are applied pieces of paper binding strip which have been previously folded longitudinally so that only about one- third of the original width of the gummed side is exposed. In this manner two slots are formed into which the films will fit at approximately the proper distance apart. The films are thus not mounted in absolutely fixed positions, but can be slid up and down and even slightly obliquely, so that they can be readily adjusted to such positions that the two images will merge when focused (Fig. 35). Fig. 36 is a view of the ordinary hand stereoscope. It is not METHODS OF LOCALIZATION 73 Fig. 32. — Central position of the tube prior to making stereoscopic film exposures. Fig. 33. — Position of tube for e.xitosure of fust film in making dental stereogram. Tube tipped inward at angle of 7 J/ degrees. 74 INTEEPRETATIOjST of PvOENTGENOGEAMS satisfactory in a bound volume to give illustrations to be viewed stereoscopically. Localization by Comparison of Two Films Taken in Different Positions This method is very useful in determining, for example, whether an unerupted tooth lies upon the lingual or the Fig. 34. — Position of tube for exposure of second film in making dental stereogram. Tube shifted and tipped outward at angle of 71/2 degrees. lal)ial aspect of the other teeth. The j)rinciple involved is explained by the following example: (1) Given two objects, standing in a straight line with the observer, the more distant will be covered by the nearer. (2) If the observer moves toward the right, the more distant object will now appear to be to the right of the nearer one. (3) Again, if the observer moves toward the left, the METHODS OF LOCALIZATION 75 nearer object will appear to be to the rigiit of the farther one. In other words, the more distant object apparently moves in the same direction as the observer, while the Fig. 35. — Method of mounting stereoscopic films so that they may be adjusted to desired positions. Fig. 36. — Hand stereoscope. nearer object apparently moves in the opposite direction. This is further brought out by continuing the lines of observation through each object on to a screen as indi- cated in the diagram. (Fig. 37.) Applying this principle now to roentgenographic films, 76 INTERPRETATIOIsr OF ROENTGENOGRAMS if an uiierupted tooth is to the lingual side of the other teeth ; i. e., farther away from the source of the ray, and two films are made, one a little farther to the right than the other, the unerupted tooth in the second film will ap- pear to be farther to the right than in the first film. On the other hand, if the unerupted tooth lies to the labial side of the other teeth, i. e., nearer the tube, it will appear to be farther to the left in the second film than in the first. In locating unerupted canine teeth, which frequently give no other indications whatever as to their lingual or labial situation, this principle yields valuable assistance, in cases where stereoscopic films may be difficult to obtain. a*£r a, €- \ " ] '\ \ i?^ \ ^^ 1 I 1 1 1 t \ \ \ \ > \ \ \ > ^..-iohitr i>«r) 1. 2. TT / / / O4, I ' 1/ \ i Fig. 37. 1. Two objects in a straight line with the observer; the more distant one is cov- ered by the nearer. 2. Observer moves to the right; the more distant object is apparently to the right of the nearer one. 3. Observer moves to the left; the nearer object is apparently to the right of the niore distant one. No claim to originality is made in describing the above method, which, so far as I am aware, originated with Mr. C. A. Clark in Bennett's Science and Practice of Dental Surgery. The ease and certainty with which it has given the desired information in numerous cases warrants its more frequent adoption and recognition, which up to now has apparently not been generally accorded. Practical examples of the method are illustrated in Figs. 226, 227, 228, and 229, pp. 128 and 129. PART II CHAPTER VII INTERPRETATION This section is devoted to a detailed descrixDtion and interpretation of numerous illustrations. Reproductions of films are presented showing both normal and abnor- mal conditions in every part of the mouth, grouped con- veniently for comparative study. The interpretations given are in conformity with the anatomic, pathologic, and clinical data discussed in the preceding chapters. The reproductions of all plates and films have been made so as to resemble the originals as closely as pos- sible. Though the double reduplication rendered neces- sary in carrying this out entails some loss of detail which would perhaps not be so marked were simple prints of the negatives used, it is believed that shortcomings in this respect are outweighed by the closer resemblance to the originals in regard to light and dark areas. The descrip- tions of the reproductions, therefore, would apply equally to the originals, without any change whatever. In illustra- tions of roentgenograms of some other parts of the body, this transposition back to the original form is perhaps not so important because these other regions are also ex- amined fluoroscoiDically, in which case the parts appear as they do in a print ; i. e., the bones and dense tissues appear as shadows instead of light areas as in the nega- tive. Since the fluoroscope is rarely applicable to dental examination, and negatives are nearly always used, it has been considered advisable to reproduce the illustra- 77 78 IE"TERPRETATIO]S: OF ROENTGENOGRAMS tions as negatives, so as to more closely apiDroach the con- ditions of examination in actual practice. In the latter part of this section are described several x-ray plates showing various conditions such as impacted third molars, cysts, fractures, etc., in which plates are frequently of more value than films. INTERPRETATIOlSr OF ROENTGENOGRAMS 79 Upper Anterior Region <1 ^ Fig. 38. Fig. 39. Fig. 38. — Upper centrals and right lateral normal. Dark area at top on right side is nasal chamber. Fig. 39. — Upper right central, lateral and canine: Pulps vital, no periapical ab- normality. Floor of nose- and maxillary sinus barely shown as dark shadows above. The thin dark peridental line and dense white bony line are seen about roots. Fill- ings shown as dense white spots. Fig. 40. Fig. 41. Fig. 40. — Upper left central, lateral, canine and premolars: Imperfect root canal fillings in canine and first premolar, shown by white line in root; no periapical ab- normalities shown. Ill-fitting shell crown on first premolar. Fig. 41. — Upper central incisors: Sharply defined dark area between roots is anterior jialatine fossa, somewhat resembling the appearance of bone destruction and cj-st formation. Ijoth teeth, however contain vital puljis, and normal peridental line can be followed around each root. 80 INTEEPRETATION OF EOENTGENOGRAMS Upper Anterior Region Fig. 42. Fig. 43. Pig, 42. — Upper right central and lateral incisors: Both teeth probably contain vital pulps; periapical tissue normal. Fig. 43. — Upper left central and lateral incisors: Pulps vital as shown by faradic test; no evidence of periapical abnormality. Some interdental alveolar bone de- struction (pyorrhea). Fig. 44. Fig. 45. Fig. 44. — Upper right central, lateral and canine: Large fillings in these teeth; pulps respond to faradic test; no periapical disturbance. Fig. 45.— Upper central incisors: Pulps vital, no periapical abnormality. Left laleral missing. The dark area between the centrals is caused by the anterior pala- tine fossa. INTERPRETATIOlSr OF ROENTGENOGRAMS 81 Upper Anterior Region Fig. 46. Fig. 47. Fig. 46. — ^^LTpper left central, lateral, canine and first premolar. Partial root filling in centra!. Crown with posts and no root filling in premolar. No periapical abnormalities. Maxillary sinus shown as dark area above premolar. Fig. 47. — Upper right central forms abutment to poorly fitting bridge, which ex- tends to left canine. Upper left central and lateral have been lost. No periapical abnormalities. The dark area above is the nasal fossa. Fig. 48. Fig. 49. Fig. 48. — Upper right lateral incisor shows post for support of crown, no other root filling; ill-defined dark area abovit apex due to chronic rarefying osteitis with suppuration. Nasal fossa with inferior turbinate well shown above. Fig. 49. — Upper right lateral incisor contains devitalized pulp (faradic test) under filling. Ill-defined dark area about apex due to chronic rarefying osteitis with sup- puration. 82 IlSrTERPKETATION OF ROENTGElsrOGRAMS Upper Anterior Region Fig. 50. Fig. 51. Fig. 50. — Upper right lateral incisor with root filling extending over apical end of root which shows absorption; fairly well-defined dark periapical area, due to chronic rarefying osteitis with granuloma. Fig. 51. — Upper left lateral incisor, imperfect root filling; irregular absorption of apex; clearly defined rounded dark area, probably due to cyst formation; would expect also to find some granulation tissue present. Pulp vital in central incisor, though the apex of the latter is apparently involved in the diseased area. Fig. 52. Fig. 53. Fig. 52. — Upper right central incisor, good root filling extending slightly beyond apex, periapical region normal. Upper left central contains devitalized pulp, shows irregular absorption of root, and rarefying osteitis with granuloma. Nasal fossTTEEPRETATION OF EOEISTTGEXOGEAMS Upper Anterior Region yMI Fig. 82. Fig. 83. Suture Fig. 82. — Supernumerary tooth between roots of upper central incisors. line is clearly shown. Fig. 83. — Pulp in upper left lateral incisor devitalized by blow. The same trauma caused a transverse fracture of alveolar process just below apex of lateral incisor, but did not fracture root. Fig. 84. Fig. 85. Fig. 84.— tjpper right central and lateral incisors after pulps had been freshly de- vitalized with arsenic and root canals filled. Fillings are seen extending to apices. Area of disease connected with canine overlaps root of lateral but does not involve it. Fig. 85. — Film of same teeth made one year later, showing absorption of both apices, with ends of root fillings extending into areas of destroyed bone, probably the result of action of arsenic. INTEEPRETATIOlSr OF ROENTGENOGEAMS 91 Upper Right Region Fig. Fig. 87. Fig. 86. — Upper right side from canine to first molar inclusive; nothing abnormal. Fig. 87. — Upper right canine normal. First premolar good root filling, apex ex- tends close to floor of maxillary sinus. First molar roots apparently project into m.axillary sinus, but in reality are in the wall of the sinus; furthermore, this tooth has a vital pulp. Fig. 88. Fig. 89. Fig. 88. — Upper right canine pulpless, good root filling, periapical condition normal. First premolar pulp vital, nothing abnormal. Second premolar missing; above the site of this tooth is a dark adea produced by the maxillary sinus. Fig. 89. — Upper right canine and premolar normal. First molar roots project above level of floor of maxillary sinus, but the normal dense line of bone can be seen surrounding the roots. The pulp of this tooth also is vital. 92 IXTERPKETATIOi^ OF EOEXTGEiSTOGEAMS Upper Ri^ht Re^on Fig. 90. Fig. 91. Fig. 90. — Upper right canine and first premolar normal. Second premolar pulpless, partial root filling, slight peridental thickening at apex. The dark space above the premolars is the maxillary sinus, separated from the roots of these teeth by a thin plate of bone. Fig. 91. — Upper right canine and first premolar contain vital pulps. Second pre- molar and first molar show filled roots extending up to but not encroaching on maxillary sinus. Fig. 92. Fig. 93. Fig. 92. — Relationship of roots of first and second molars to maxillary sinus shown; they project above the level of the floor, but do not encroach on cavity. Fig. 93. — Roots of second premolar and first molar apparently projecting into maxillary sinus, but a thin partition of bone can be seen covering the roots. USTTEEPRETATIOX OF ROEjSTTGEXOGRAMS 93 Upper Right Region Fig. 94. Fig. 95. Fig. 94. — Normal relationship of roots of premolars and molars to maxillary sinus. Fig. 95. — First molar pulpless, imperfect fillings in buccal roots; lingual root filled to ape.x; no periapical abnormalities, though roots apparently project into maxillary sinus. Fig. 96. Fig. 97. Fig. 96. — First premolar crowned, imperfect root filling, peridental thickening at apex. Second premolar crowned, no root filling, pulp may be vital; apex very near floor of maxillary sinus. First molar missing. Fig. 97. — First and second premolars pulpless, partial root fillings, no abnormal periapical conditions. First molar missing, and floor of maxillary sinus projects well down between second premolar and second molar. 94 INTERPRETATION OF ROENTGENOGRAMS Upper Rig-ht Region Fig. 98. Fig. 99. Fig. 98. — Fii-st premolar, good root filling in buccal root, partial filling in mesial root; second premolar, partial root filling; pericemental thickening about apices of Ijoth teeth. First and second molar normal, third molar impacted. Fig. 99. — Canine and second premolar pulpless, partial root fillings, pericemental thickening about apices. First premolar and first and second molars, no periapical abnormalities. Fig. 100. Fig. 101. Fig. 100. — Second premolar, good root filling, periapical thickening. Second molar, Ijadly fitting crown. Fig. 101. — Second premolar crowned, partial root filling; dark periapical area with irregular outline, denoting chronic rarefying osteitis with suppuration. INTERPRETATION OF EOENTGEjSTOGRAMS 95 Upper Rig-ht Region Fig. 102. Fig. 103. Fig. 102. — First premolar crowned, imperfect root fillings, periapical rarefaction, probably with suppuration. First molar pulpless, probably chronic rarefying osteitis with granuloma at apex of lingual root. Fig. 103. — First premolar i)uli)less, no root fillings, area of periapical rarefying osteitis with granuloma. Fig. 104. — Canine, premolars and molars show absent or imperfect root fillings, liadly fitting crowns, and overhanging edges of fillings. First premolar, large area of periapical bone destruction, probably suppuration, and erosion of cementum. Fig. 105. — Upper right first molar crowned, palatal root shows area of jicriapical bene destruction probably e.xtending into maxillary sinus. 96 INTERPRETATION^ OF ROENTGENOGRAMS Upper Right Region Fig. 106. Fig. 107. Fig. 106. — The partition of bone between the second molar and the maxillary sinus has been destroyed by periapical d'sease, producing; a direct communication of this tooth with the maxillary sinus and secondary infection of that cavity. The second premolar, although containing a part'al root rtUing, and _ presenting some periapical thickening, is separated from the antrum by a bony partition. The apices of the canine and first premolar show nothing abnormal, but lie very close to the floor of the sinus. Fig'. 107. — Second premolar crowned, partial root filling, periapical region normal. First molar crowned, imperfect root fillings, erosion of cementum and large periapical area of chronic rarefying osteitis with suppuration and granuloma. Note floor of maxillary sinus just above this area. Fig. 1( Fig. 109. Fig. 108. — First premolar crowned, practically no root filling, small periapical area of chronic rarefying osteitis with granuloma. Second premolar normal. Part of first molar root extending into maxillary sinus. Fig. 109. — Small apical portion of first molar root in maxillary sinus. IXTERPr>ETATIOX OF ROEXTGEXOORAMS 97 Upper Right Region Fig. 110. Fig. 111. Fig. 110. — Upper right first premolar crowned, partial root filling, periapical area of bone destrnction due to chronic rarefying osteitis with granuloma. Fiff. 111. — l'|iper right second premolar crowned, partial root filling; periapical granuloma. Considerable thickness of bone between the diseased area and the max- illary sinus. Fig. 112. Fi.g. 113. Fig. 112. — Upper right second premolar ]nil|:iless, very imjierfect root filling, i)eri- apical area of rarefying osteitis with granuloma, separated by very thin septum of bone from maxillary sinus. Fig. 113. — Upper right second premolar probably contains infected pulp; area of jieriapical bone destruction with granuloma separated by thin partition from maxillary sinus, forming a distinct prominence in its floor. ustterpketatiojst of roentgenograms Upper Right Region Fig. 114. Fig. 115. Fig. 114. — Second premolar infected pulp canal, no evidence of root filling, large periapical area of chronic rarefying osteitis with granuloma, separated from max- illary sinus by thin plate of bone which forms a prominence in its floor. Fig. 115. — First premolar infected pulp canal, no evidence of root filling; periapical area of chronic rarefying osteitis and granuloma reaching up to floor of maxillary sinus. Fig. 116. Fig. 117. Fig. 116. — Upper right first premolar forms abutment of bridge; transverse frac- ture of root at junction of upper and middle thirds. Fig. 117. — Large lateral area of bone destruction in region of upper right canine. Second premolar crowned, imperfect root filling, apical region normal. Dark area over first molar is due to a recess in the maxillary sinus. First molar has a vital pulp and no abnormality about roots. INTERPRETATIOlSr OF EOENTGENOGRAMS 99 Upper Left Region Fig. 118. Fig. 119. Fig. 118. — Upper left teeth from central incisor to second premolar, pulps vital, periapical conditions normal. Destruction of bony septum between lateral incisor and canine due to pyorrhea. Apex of second premolar near floor of maxillary sinus. Fig. 119. — Normal lateral incisor, canine, first and second premolars, and first molar. Pulps all vital.' Maxillary sinus does not extend farther forward than first molar, and is seen just above apices of this tooth. Fig. 120. Fig. 121. Fig. 120. — Roots of upper left teeth from central incisor to second premolar, all normal. Fig. 121. — Maxillary sinus extends well forward over apex of canine. No ab- normal periapical conditions. 100 IjSttekpeetatioi^ of roentgenograms Upper Left Region Fig. 122. Fig. 123. Fig. 122. — Upper left first premolar crowned, partial root filling, periapical region normal. First molar, crown with overhanging edge, apices normal though appar- ently projecting into maxillary sinus. Fig. 123. — Upper left canine to third molar. All apical regions normal. First molar probably missing, and rudimentary third molar present, koots of second molar shown in wall of maxillary sinus. Fig. 124. Fig. 125. Fig. 124. — Upper left canine, and first and second premolars. Pulps vital. Normal pericemental line seen around roots. Floor of maxillary sinus also shown. Fig. 125. — No periapical abnormalities. Apices of second premolar and first molar very close to floor of ma'cillary sinus. INTERPEETATION OF ROENTGENOGRAMS 101 Upper Left Region Fig. 126. Fig. 127. Fig. 126. — First molar has large filling on distal aspect. Outline of disto-buccal root is indistinctly shown above this. Bone destruction around filling causes a pocket. Fig. 127. — First premolar crowned, two roots, one much foresliortened; good root fillings, apices normal. Other teeth normal. First molar missing. Second and third molar roots overshadowed by malar bone. IPI WM n »-.■' .''WB k. J |1 s Fig. 128. Fig. 129. Fig. 128. — Upper left premolars, inilps vital, periapical regions normal. Circum- scribed dark area about apex of second premolar somewhat resembling an area due to rarefying osteitis is only due to a recess in the maxillary sinus; the normal line of bone can be traced completely around the apex of this tooth. Light shadow in upper left corner is due to malar bone. Fig. 129. — -Upper left first premolar crowned, imperfect root fillings, periapical region normal. Second premolar pulp vital. The white line apparently running from its apex is due to a septum in the maxillary sinus. 102 IlsrTEEPEETATIOlSr OY ROENTGENOGRAMS Upper Left Region Fig. 130. Fig. 131. Fig. 130. — Upper left second pre.-nolar pvilpless, no root canal filling; thickening of peridental membrane due to inflammation about apex, which is ver\' close to floor of ma-xillary sinus. Fig. 131. — Upper left canine, root tilling only extends about half way, apex ap- parently encapsulated with healthy bone. First premolar crowned. The tdm is over- exposed, but shows that the root of this tooth is absorbed and surrounded by area of bone destruction with granuloma. Second premolar crowned, partial root filling, with apex involved in a common area of l^one destruction and granuloma with mesio- buccal root of first molar which contains no root filling. Fig. 132. Fig. 133. Fig. 132. — Upper left premolars and molars have poorly fitting crowns, responsible for gingival infectdon and absorption of bone around necks of teeth. First premolar shows no root filling and peridental thickening. Second premolar, partial root filling, periapical bone destruction and granuloma. Same condition of first molar. Second m.olar, probably no periapical disease, but buccal roots denuded from pyorrhea. Fig. 133. — Upper left first premolar crowned, no root filling, post of crown per- forating side of root; about site of perforation is an area of chronic rarefying osteitis with granuloma; periapical thickening of peridental membrane. INTERPRETATION OF ROENTGENOGRAMS 103 Upper Left Region Fig. 134. Fig. 135. Fig. 134. — Upper left first premolar, decay under filling. Second premolar crowned, imperfect root filling, which, however, extends to apex, periapical region normal. First molar pulpless, apparent area of rarefaction about apex of lingual root, but close scrutiny reveals cancellated bone in this position. A bony promi- nence over this tooth projects into maxillary sinus. Fig. 135. — First premolar shows fracture of root at junction of upper and middle thirds; pulp of this tooth remained vital for several years after fracture. Fig. 136. Fig. 137. Fig. 136. — Upper left maxillary sinus extends forward to canine, which is normal. First premolar crowned, periapical thickening of peridental membrane due to chronic proliferative pericementitis. Second premolar vital pulp, apex normal, though extend- ing to floor of maxillary sinus. First molar crowned, periapical area of bone destruc- tion about lingual root, in wall of maxillary sinus. Fig. 137. — Apex of second premolar insufficiently shown for diagnosis. First molar crowned, imperfect root fillings, chronic periapical rarefying osteitis with granuloma, extending to floor of maxillary sinus. 104 INTERPRETATIOiSr OF ROElN^TGElSrOGEAMS Upper Left Region ■-.l*^ M HMH^^ 1 i 7- l^^^l Fig. 138. Fig. 139. Fig. 138. — Large sharply defined area of bone destruction above premolars and first molar. Probably cyst formation arising in connection with first molar, whose roots are seen to be eroded. The cyst cavity probaljly enci caches on the maxillary sinus, which, is seen above the second molar. Fig. 139. — First premolar crowned, partial root filling, apex probably normal. Second premolar crowned, partial root fillings, apex probably normal. First molar shows a large area of bone destruction about apex of lingual root. Absence of root fillings would indicate presence of dead pulp. Destruction of bone septum between first and second molars due to pyorrhea from overhanging edge of filling. Fig. 141. Fig. 140. — Condition about premolars is ill-defined, owing to overexposure of film. First molar crowned, imperfect root fillings. Apex of lingual root is seen in wall of maxillary sinus surrounded by an area of bone destruction which probably communicates with the sinus. The bony septum between the two molars is destroyed by pyorrhea except its apical third. Practically no bony attachment to second molar. Fig. 141. — First premolar pulpless, poor root filling, periapical thickening of peri- dental membrane due to chronic proliferative pericementitis. Apex very close to maxillary sinus. Large area of bone destruction with granuloma ahout apices of last molar. IliTTERPRETATIOlSr OF ROENTGENOGRAMS 105 Upper Left Region Fig. 142. Fig. 143 Fig. 142. — Second premolar, partial root filling, apex normal. Apical portion of root of first molar remaining after extraction. Fig. 143. — Upper left second molar forms posterior abutment of bridge. Bone completely destroyed around buccal roots. Fig. 144. Fig. 144. — First premolar, perforation of side of root with large area of bone destruction surrounding the perforation; apex normal. Fig. 145. — Apical region of crowned premolars normal. First molar missing. Deep [locket due to pyorrhea just in front of second molar. 106 I]SrTEEPEETATIO:N- OF KOE^STTGEXOGEAMS Upper Left Region . mm- a Lii. Fig. 146. Fig. 147. Fig. 1411. — Decay beginning on mesial surface of upper left canine near cervical margin. First premolar crowned, two roots, apparently good root fillings, large, irreg- ular, clearly defined periapical area of chronic rarefying osteitis with granuloma. Sec- ond premolar normal. Fig. 147. — First molar, pulp probably vital; extensive jjyorrheal bone destruction, extending between roots. Second molar, badly fitting crown, poor root fillings, but apical region normal. Fig. 148. Fig. 149. Fig. 148. — Upper left canine and first premolar normal. Impacted first molar, sur- rounded by an area of bone destruction involving apex of second premolar. F'ig. 149. — Upper left canine pulpless, apparently good root filling, considerable ]ieriapical area of bone destruction with granuloma. Dark area to left is maxillary sinus. II^TERPFvETATIOX OF EOEXTGEXOGEAMS 107 Upper Left Region Fig. 150. Fig. 151. Fig. 150. — First premolar crowned, no root filling, marked curvature of root, apex- normal. Second premolar crowned, partial root filling, periapical chronic rarefying osteitis with granuloma. This area forms a projection which is walled off from the maxillary sinus by a thin plate of bone. Fig. 151. — Upper left first. premolar crowned, imperfect root filling, no periapical abnormality. Second premolar, poorly fitting crown, leading to infection and ab- sorption of alveolar septum; apparently good root filling; periapical bone destruction, granuloma, and roughening of apex. Fig. 15: 153. Fig. 152. — Second premolar crowned, with decay shown under edge of crown; no root filling, canal probably contains necrotic pulp tissue; chronic larefying osteitis with granuloma about apex, which projects above floor of maxillary sinus, but is sep- arated from it by a thin plate of bone. White line extending vertically upward from apex indicates a septum in maxillary sinus. 153. — -Upper left second premolar, death of pulp under filliiiE ajiical area of bone destruction indicating suppuration. Ill-defined peri- 108 HSTTERPRETATION OF ROENTGENOGRAMS Upper Left Region Fig. 1S4. Fig. 155. Fig. 154. — Second premolar, bridge abutment, nothing abnormal .seen at apex. First molar, death of jnilp beneath filling; area of bone destruction about apex of palatal root, well above floor of maxillary sinus. Fig. 155. — Another view of first molar shown in opposite illustration. Fi.^. 156. Fig. 157. Fig. 156. — Upper left lateral incisor crowned, post does not follow root canal, Ijut passes to side of root, no root filling, apical region apparently normal. Canine, large filling extending to pulp chamber, no root filling, root canal evidently contains infected pulp tissue; large area of chronic rarefying osteitis with granuloma around apex of this tooth and extending almost down to neck on mesial side. First pre- molar crowned, extensive root absorption and chronic periapical rarefying osteitis with granuloma, extending to root of second premolar. Second premolar, decay on distal surface; above this is a jiartial loss of alveolar septum due to pyorrhea. Fig. 157. — First premolar pulpless, no root filling, apex involved in large area of chronic rarefying osteitis with granuloma extending to region of second premolar, which has been lost. II^TERPRETATION OF ROENTGENOGRAMS 109 Upper Left Region Fig. 158. Fig. 159. Fig. 158. — Large area of chronic rarefying osteitis with clearly defined walls in- dicating cyst formation. This has probably arisen from infection connected with the first premolar, which is crowned, and contains an imperfect root filling. Fig. 159. — Same case as in opposite film, following extraction of first premolar and curettement of cyst cavity. Taken six weeks later; regeneration of bone is taking place, as indicated by haziness of outline of cavity, and lessening in size of rarefied area. Fig. 160. Fig. 161. Fig. 160. — Large area of bone destruction in region between upper left second jiremolar and first molar; irregular margins indicating chronic rarefying osteitis with suppuration. Permanent canine and second molar unerupted. Infection probably arose in connection with deciduous molar. Fig. 161. — Distortion present, but film shows large area of bone destruction around pulpless upper left first molar, apparently communicating directly with the maxil- lary sinus. 110 nSTTEEPRETATTON OF ROENTGENOGRAMS Lower Front Region Fig. 162. Fig. 163. Fig. 162.— Lower central and lateral incisors, pulps vital, normal bony jc-ray anatomy. Fig. 163. — Lower central and lateral incisors, normal. Fig. 164. Fig. 165. Fig. 164. — Lower right central and lateral incisors in center of film; pulps vital, bone normal. Fig. 165. — Lower central and lateral incisors, normal. INTERPRETATIOIir OF ROENTGE^STOGRAMS 111 Lower Front Region '"% ^Tl IP •^o H^ Fig. 166. Fig. 167. Fig. 166. — Area of chronic rarefying osteitis with granuloma about apices of lower right central and lower left central and lateral incisors. It is difficult to tell which of these teeth is responsible as all contain dead pulps. Fig. 167. — Lower right central incisor pulpless, partial root filling, periapical area of chronic rarefying osteitis with granuloma. Fig. 168. Fig. 169. Fig. 168. — Dead pulp in lower left lateral incisor. Periapical area of chronic rarefying osteitis with suppuration. Fig. 169. — Lower left lateral incisor pulpless; root filling extends through ape.x into previously existing bone cavity due to chronic rarefying osteitis. 112 INTERPRETATIOiSr OF EOEISTTGENOGEAMS Lower Front Region Fig. 170. Fig. 171. Fig. 170. — Dead pulp in lower right central incisor; periapical area of chronic rare- fying osteitis with granuloma. Fig. 171. — lyarge area of bone destruction with sharply defined edges due to cyst involving roots of lower right central and lateral and left central incisors. Left lat- eral incisor missing. Pulps dead in central incisors, but vital in right lateral and left canine. Cyst probably followed chronic rarefying osteitis in connection with death of the pulp of one of the central incisors. ect of the other teeth. INTERPEETATIOX OF EOEXTGEXOGEAMS 129 Localization of Impacted Canine Fig. 228. — Upper left' impacted canine. In A, a more anterior view than B. the cusp of the canine completely overlaps the root of the central incisor, while in B it only overlaps the root of the lateral, showing that the c?nine lies on the lingual or jialatal aspect of the other teeth. 1^^^ A. B. Fig. 229. — Upper left impacted canine. In A, a more anterior view than B, the cusp of the canine only reaches the distal side of the root of the lateral incisor, while in B it partially overlaps the root of this tooth, showing that the canine lies on the laliial aspect of the other teeth. A part of the temporary canine is seen in B. 130 INTERPRETATION OF ROENTGENOGRAMS Horizontal Impaction of Lower Molars Fig. 230. — Horizontal impaction of the lower left third molar. Crown not cov- ered by bone. Decay of crown of second molar, shown by dark area. Upper third molar unerupted, and lying slightly to one side of second molar. Fig. 231. — Horizontal impaction of lower right third molar. OccUisal surface of crown is tightly in apposition with posterior surface of crown and root of second molar. Upper third molar partially erupted with occlusal surface of crown directed backward. INTEEPEETATIOX OF EOEXTGEXOGRAMS 131 Fig. 232. — Horizontal impaction of lower left third molar. 132 INTERPRETATION OF ROENTGENOGRAMS Fig. 233. — Horizontal impaction of lower right third molar with decaj' of crown of second molar. Upper third molar unerupted. The light body shown above the premolar teeth is an unerupted third molar on the opposite side. Fig. 234. — Oblique impaction of lower left third molar. Crown is largely covered by bone. INTERPRETATION' OF EOEXTGEXOGEAMS 133 Fig. 235. — Impacted lower left third molar. Crown well erupted, and roots straight and spread apart. Dark area in crown indicates caries. Fig. 236. — Impacted uneru]ited lower k-tt tliird molar. Roots only partially devel- oped. Uneriipted upper third molar, apparently in good position. 134 IK^TERPRETATIOX OF EOENTGEjSTOGEAMS Fig. 237. — Impacted unerupted lower premolar on left side. This patient already- had two premolars erupted and in good position on the left side, and three on the right side. In the upper jaw, the normal number of teeth were present. Fig. 238. — Supposedly edentulous patient 81 years of age. The arrow points to an unerupted canine with the crown directed forwards. Above is seen a film giving a better view of this tooth. IXTERPEETATIOX OF ROEXTGEXOGRA:\rS 135 Cysts Fig. 239. — Large area of bone destruction in left angle and ramus of mandible. Sharply defined outlines of this area make diagnosis of cyst probable. Patient gave history of having had abscessed condition and bone infection connected with third molar and operation many years before. At time roentgenogram was made, left side .01 face was swollen, there was difficulty in opening the mouth, ^!id a small sinus was found on the upper aspect of the gum at the site of the lov/er third molar, through which a thin fluid discharged into the mouth. A diagnosis was made of dental cyst, probably originating from epithelial remnants around the third molar, left behind at the first operation. At operation, the thin bone overlying the cavity was rongeured away and the fluid contents and cyst wall removed. It was possible to pass a probe within the cavity almost up to the mandibular articulation, and down through a per- foration into the neck. The diagnosis of cyst was confirmed by microscopic examina- tion of the tissue removed, which showed a condition similar to that in Fig. 20. Fig. 240. — Roentgenogram of same case taken four months later, showing almost com- plete obliteration of cyst cavity by regeneration of bone. 136 IXTEEPRETATION" OF EOEXTGEXOGEAMS Cysts A. B. Fig. 241. — A. Cyst of right side of upper jaw, arising in connection with small piece of root of first molar. The cyst extended upward encroaching upon the cavity of the maxillary sinus, but not communicating with it. B. Film showing more details of cyst. Light area in upper right corner is the shadow cast by the malar bone. Osteomyelitis Fig. 242. — Right side, showing extensive bone destruction of lower jaw due to acute osteomyelitis. The infection started two weeks previously in connection with the second molar. The condition involved the lower jaw from angle to angle, all of the teeth being extruded. (Case of Dr. A. J. Kuhnmuench.) IXTERPRETATIOX OF R(3EXTGEX0GRAMS 137 Cysts Fig. 243. — Large area of bone destruction on right side of mandible due to cyst formation probably arising in connection with irritation following periaoical infec- tion about the second premolar and first molar. Observe sharp outline of cavity. Fig. 2AA. — Large infected cyst of right side of mandible due to infection about roots of first molar, which bad been lost some time previously. 138 IXTEEPRETATIOX OF EOEXTGEXOGEAMS Odontomas Fig. 245. Fig. 246. Fig. 245. — Calcified composite odontoma of right side of mandible in an adult. Patient for several years had had several sinuses discharging on the skin at the lower border of the jaw. In the mouth, the teeth were absent, but pus discharged through several sinvises at the bottom of which bard substance could be felt with a probe. X-ray shows several irregular masses, denser than bone, in places resembling tooth structure. Fig. 246. — Calcified composite odontoma of lower jaw resembling in history and clinical signs the preceding case. Fig. 247. — Calcified composite odontoma in a boy ten years of age. Symptoms be- gan with inflammatory swelling of lower jaw, pus finally pointing externally and drained by incision near angle of jaw. A diagnosis of osteomyelitis was made. Swelling and pus discharge were still present when first seen ljy author two weeks after incision. No molar teeth erupted, and no history of ever being present. X-ray shows unerupted first molar near lower border of jaw. Behind and above this is seen a dense irregular mass, in places showing outlines of parts of teeth, extending well back into ramus of jaw. Operation consisted in removing the mass and the unerupted tooth from within the mouth. Tumor weighed IJ/2 oz. IXTERPRETATIOX OF ROEXTGEXOGRA.MS 139 Fig. 248. — Periapical bone destruction connected with lower left second molar. Patient, fourteen years of age, had lost first molar on that side some years pre- viously. For several months had had a sinus discharging through the skiii just be- low the lower border of the mandible. The second molar appeared normal except for a large filling. On extraction of this tooth a dead infected pulp was found. The crowns of the unerupted upper and lower third molars with undeveloped roots are shown. Upper third molar of opposite side is seen as a light area above the premolar region. Fig. 249. — Retained piece of root of lower left first molar, which gave rise to chronic sinus with purulent discharge beneath jaw, extending over a period of years. 140 IXTEEPEETATIOX OF EOEXTGEXOGEAMS Fig. 250. — Root of upper right first molar lost in maxillary sinus during at- tempted extraction. A plate should always be made in a case of this kind, the two sides of the face being made to overlap as much as possible, so that the maxillary sinus will not be obscured by the bone of the opposite side. Fig. 251. — Root of upper right first molar lost in maxillary sinus during attempted extraction. INTERPRETATIOIN' OF EOEXTGEXOGrtAMS 141 Fig. 252. — Roentgenogram of right side, showing lack of development of both pre- molars and third molar in upper jaw and second premolar and third molar in lower jaw. Patient gave history of never having erupted upper first and second premolars and lower second premolar on either side. Referred by Dr. Carl B. Case for roent- ger.ographic examination. Fig. 253. — Same case, showing similar condition on left side. 142 IjSfTEEPEETATIOX OF EOEXTGEXOGEAMS Fractures Fig. 254. — Fracture of left side of mandible just in front of second molar. First molar missing. The line of fracture in this region is nearly always oblique, running from above downward and backward. Fig. 255. — Fracture of left side of mandible in second premolar region. The root of this tooth is found in the line of fracture, and will jircliably lequire extraction before union can occur. IXTEEPRETxVTIOX OF EOEXTGEXOGRAMS 143 Fractures > > ^l^^^^Ev 1 H^ i .Jhh J Fig. 256. — Fracture of left side of mandible near canine tooth, with very few teeth present. This is said to be the commonest site for fracture to occur. Fig. 257. — Fracture through neck of condyle of mandible. The lower end of the small fragment in these cases is generally pulled forward by the external pterygoid muscle. The ramus of the jaw is disjilaced externally to the smaller fragment, caus- ing the lower teeth to be drawn over toward the affected side. 144 i:n'terpretatio:n' of roeittgenograms Fractures Fig. 258. — Double fracture of mandible in molar region on each side. Attempted fixation by means of Lane's plates. The plates had to be removed after two weeks owing to infection and nonunion. Fig. 259. — Same case, showing swaged metal intermaxillary splint in position. INDEX A Abscess, chronic, 40 Alveolar process, fracture of, 90 Anatomic landmarks, roentgeno- graphic, 26 Anatomy in relation to roentgenog- raphy, 24 B Bone regeneration, 109, 126, 135 C Calcification of tooth, incomplete, 116, 119 Caries, dental, 103, 106, 107, 108, 114, 119 ■ Cementum, erosion of, 95, 107 Clinical examination, 49 Coronoid process, 34 Cyst formation, 42, 82, 89, 104, 109, 112, 125, 126, 135, 136, 137 D De1)ris epitheliaux paradentaires, 44 Density, relative, of various sub- stances in regard to x-ray, 24 E Empyema of maxillary sinus, 58 Ethmoid cells, 34 Examination, positions emi^loyed, 5c record of, 52 Exostosis, subperiosteal, 118 Faradic test, 50 Film stereograms, 70 Films, identification of, 60 illustrating root canal treatment, 121-125 lower front region, abnormal, 111, 112, 113 lower front region, normal, 110 lower left region, abnormal, 118, no, 120 Films— Cont 'd lower left region, normal, 117, 118 lower right region, al>normal, 114, 115, 116 lower right region, normal, 113, 114 position for exposure of, 57 ujiper anterior region, almormal, 81-90 upper anterior region, normal, 79, 80, 81 upper left region, abnormal, 102- 109 upper left region, normal, 99, 100, 101 upper right legion, abnormal, OS- OS upper right region, normal, 91, 92, 93 Floor of nose, 26, 81 Fracture, alveolar process, 90 mandible, 142-144 root, 88, 98, 103 G Gingivopericementitis, 47 Granuloma, 40 H Histopathologv of periajiical lesions, 38 Hyoid bone, 35 Hypercementosis, 120 Identification of plates and films, 59 Impacted canine, upper, 127, 128, 129, 134 Impacted first mnlar, upper, 106, 127 Impacted premolar, lower, 116, 134 Impacted third molar, lower, 130- 134 Impacted third molar, upper, 94, 124 Interpretation, 77 Localization, 23 by comparison of two films. 74 145 146 INDEX Localization — Cout 'd of impacted canine, 128, 129 stereoscopic, 67 M Mandibular canal, 31, 35, 115, 120 Maxillary sinus, 2(3 involvemeut in periapical disease, 95, 96, 104, 109 relation of roots of teeth to, 91, 92, 93, 99, 100, 101 tooth root in, 140 septum in, 101, 107 Mental foramen, 31, 35, 113, 118 X Xasal fossa, 26, 81 O Odontogram, definition of, IS knowledge necessary for interpre- tation of, 19 Odontoma, calcified, 138 Osteitis, chronic rarefying, arseni- cal, 90 with granuloma, 82, 83, 81, 85, 86, 87, 88, 95, 96, 97, 98, 102, 103, 104, 106, 107, 108, 111, 112, 113, 114, lis with suppuration, 81, 84. So, 87, S9, 94, 95, 96, 107, 109, 111, 114, 115, 119, 120, 139. Osteomyelitis, acute, 136 Osteopericementitis, 47 Palatine canal, posterior, 31 Palatine fossa, anterior, 30, 79 Pathology, in relation to dental roentgenology, 36 Perforation of root, 86, 87, 102, 105, 108, 118 Periapical dental lesions, pathology of, 37 Periapical disease, stages, 38, 45 Pericementitis, chronic suppurative, 46, 88, 102, 104, 105, 106, 112, 113, 116 periapical, chronic, 84. 85, 87, 88, 93, 94, 102, 103, 104, 112, 115, 116, 118, 120 Peridental line, 25, 79, 100 Peridental thickening, 40 Plate rest, 56 Plate stereograms, 68 Plates, identification of, 59 position for exposure of, 56 roentgenographic landmarks in, 33 use of, 51 Prognosis as aided bv roentgen rav, 62 Pulp, test for vitalitv of, 50 Pyorrhea alveolaris, *46, 65, 88, 102, 104, 105, 106, 112, 113, 116 R Rarefying osteitis, chronic, 45 Record of examination, 52 Resection of root, 122, 126 Roentgenogram, 18 Roentgenograms, interpretation of, 77 Roentgenographic findings in rela- tion to prognosis and treat- ment, 62 Roentgenography, limitations of, 20 Roeirtgenologic examination, posi- tions used, 53 Root, fracture of, 88, 98, 103 perforation of, 86, 87, 102, 105, 108, 118 Routine examination, 49 S Sinuses, j^osition for examination of, 57 Stereogram, 18 Stereograms, mounting, 72 Stereoroentgenography, 67 Stereoscopic localization, 67 Streptococcus, 38 Supernumerary tooth, 90, 134 Suppurative pericementitis, clironic, 65. 88. 102. 3 04, 105, 106, 112, 113 116 T Teeth, absence of. 141 anatomic relations to maxillary sinus, 26 Terms, explanation of, 18 Tootli, supernumerary, 90, 134 Treatment, bearing of x-ray examin- ation on, 63 JO AJadoij RK270