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Dense bone island
Dense bone island A review of 107 patients Donal McDonnell, DIVISION
OF ORAL
BDS, FFDRCSI, RADIOLOGY,
MSca Vancouver, British Columbia, Canada
FACULTY
OF DENTISTRY,
THE
UNIVERSITY
OF BRITISH
COLUMBIA
The dense bone island is an asymptomatic radiopacity of unknown origin and is known under many synonyms when it occurs in the jaw. This article discusses 113 dense bone islands in 107 patients with a review of the literature and comparison with previous reports. The average age of the patient at discovery was 36 years with a women to men ratio of 2:l. The mandible was involved in 109 of the 113 DBls, with only 4 in the maxilla. The most common site affected was the mandibular first molar region, the premolar region was the second most common site affected. Resorption occurred in 11 (9.7%) cases, the first permanent molar was the most commonly affected. (ORAL SURC ORAL MED ORAL PATHOL 1993;76:124-8)
The entity, dense bone island (DBI), may be described as a localized area of radiopacity of unknown origin that is not attributable to any other condition. Fig. 1 illustrates examples of this entity, both related and unrelated to the roots of teeth. The condition is usually asymptomatic and discovered on a radiograph taken for some other reason. The radiopacity is of variable size, shape, outline, and density. It may be associated with the roots of teeth or be totally separated by normal trabecular bone. When a DBI occurs in the tooth-bearing area of the jaw, many synonyms are used as indicated in Table I. Poyton and Pharoah’ and Miles et al.2 mention DBI but most references use the terms osteosclerosis,2-9 osteopetrosis,‘0-‘2 condensing osteitis,13 and enostosis.5,6, l3 Worth13 describes this condition as condensing or sclerosing osteitis, but most authorities differentiate between osteitis and DBI. Condensing osteitis, also known as inflammatory sclerosis, is generally considered to be a lesion of inflammatory origin and associated with a nonvital tooth, with an area of radiolucency between the radiopacity and the root.2, 5,6-9,14,l5 Others16-‘9 use the terms osteosclerosis and osteitis interchangeably. The many synonyms used, as well as the difference in interpretation of terminology, can make for confusion and difficulty in the literature. Keats20 indicates that bone islands are variations of normality and shows examples in the first lumbar vertebra, iliac bone, and the capitate and lunate bones of the hand. There have been few surveys on this condition in the literature. Farman et al.3 compared the incidence in “Europeans” with Cape Coloured. They found no difference between men and women; no difference Copyright @ 1993 by Mosby-Year Book, 0030-4220/93/$1.00 + .lO 7/16/43992
Inc.
between patients under or over 25 years of age, and equal proportion of both races affected with lesions associated with noncarious restored teeth. The most common site in both races was the mandibular first molar region. Geist and Katz4 examined the radiographs of 192 1 patients and reported an incidence of 5.4%. They found no difference between women and men, the ratio of women to men was 1.5:1 and a significantly higher frequency among black females. The most common site affected was the mandibular premolar region. Eversole et al.” discussed the radiographic patterns in 41 patients for which histopathologic confirmation was available. Histologically there is dense lamellar bone and small marrow channels. Inflammatory cell infiltration is generally lacking. The most common site affected was the mandibular first molar region, and five radiographic patterns were described. There is no known cause, and no treatment is indicated. It has been suggested that excess occlusal stress can be a factor in DBI associated with the roots of teeth.7, l1 Retained primary roots have also been implicated as a cause,6 but this could not account for DBIs on the distal aspect of the primary dentition. Generally the term idiopathic is used as a definite cause that cannot be identified. It is important to distinguish DBI from other conditions, such as periapical cemental dysplasia, submandibular calculus, torus, exostosis, osteoma, odontome, or condensing osteitis (inflammatory sclerosis) related to nonvital teeth, as the treatment is different. This study reviews the radiographs of 107 patients, all of whom had asymptomatic radiopacities that could not be attributed to any other known condition. The age and sex of the patients, as well as the distri-
ORAL SURGERYORAL MEDICINE ORAL PATHOLOGY Volume
76. Number
McDonnell
125
1
Fig. 1. Examples of densebone islands. A, DBI related to lower right first molar. B, DBI below lower right first molar. C, DBI below and between noncarious lower left tirst and secondmolar and extending to alveolar crest. D, Example in edentulous left maxilla. E, Part of panoramic radiograph shows two DBI in right canine and premolar region. F, DBI associatedwith resorbed distal root of lower right first molar.
bution by location is outlined. The results are compared with previous reports. MATERIAL AND METHODS This survey included 107 patients gathered from the files of current patients under treatment at the Faculty of Dentistry at the University of British Columbia and from general dentists in the Province of British Columbia who submitted cases. In the mandible, only radiopacities above the inferior alveolarcanal were considered. The radiopacity could be tooth related or separated from the lamina dura by normal trabecular pattern. The following criteria were used for inclusion in the survey: 1. a well-defined area of radiopacity in the toothbearing ‘arlea of the jaw 2. nio surrounding radiolucent space 3. not typical of any other condition The following criteria were used for exclusion from the survey: 1. radiopacities in the maxilla considered to be in the maxillary sinus 2. if clinical examination showed an exostosis or the presence of a torus in the area of the DBI
Table
I. Synonyms for dense bone island Osteosclerosis2-9 Condensing osteitis13 Bone eburnation7 Bone scar*, l2 Osteopetrotic scarlo
Table
Osteopetrosis*a ‘O-‘* Enostosis’x 2,5%6,7,13 Sclerotic bone62l2 Socket sclerosi& 8, 9 Bone whorl’
II. Comparisons from various surveys
No. of patients No. of DBI Women Men No. in mandible No. in maxilla First molar Second molar Premolars Resorption One DBI Two DBI
Farman et aL3 (“/oi
Eversole et al.” (%o)
Geist and Katz4 (%)
McDonnell (%I
252 392 302 90 116 61 13 -
41 41 41 0 23 8 9 5 41 0
103 112 61 42 100 12 20 36 105 7
107 113 72 (67) 35 (33) 109 (96) 4 (4) 54 (49) 13 (12) 27 (24) 11 (10) 101 (94)
(77) (23) (30) (16) (3)
(100) (0) (56) (20) (22) (12) (100) (0)
(59) (41) (89) (11) (21) (32) (94) (6)
Percentages have been rounded to the nearest full percent.
6 (6)
s126; McDonnell
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY July 1993
46
36
37
TCJQth Fig. 4. Histogram illustrates presenceof resorption associated with molar teeth. M + D = mesial and distal roots, M = mesial root only, D = distal root only. Fig. 2. Histogram illustrates agerange of 99 patients. Age was not known in 8 patients.
Fig. 3. Histogram illustrates distribution of DBI in mandible. 3. if symptoms were present in the area of the DBI Two observers reviewed the radiographs and agreed on the radiographic diagnosis. If there was any disagreement or doubtful diagnosis, the patient was excluded from the survey. Information relating to site, sex, age, race, and presence of resorption was recorded. RESULTS A total of 107 patients with 113 DBIs were included in the study; 101 patients had one DBI and six patients had two DBI. Seventy-two patients were women (67.3%) and 35 were men (32.7%), which is a woman to man ratio of 2: 1.
Age was known in 99 patients and, at the time of the discovery of the DBIs, ranged from I2 to 83 years, with a mean age of 36.0 years (Fig. 2). The race was known in 92 patients (84%) and was distributed as follows: white, 76 (7 1.O%); Orientals, 15 ( 14.0%); and black, 1 ( 1.O%). Of the 113 lesions, 109 were present in the mandible (96.5%), with only 4 (3.5%) in the maxilla. Fig. 3 shows the distribution in the mandible, with no radiopacities present in the central incisor region. The highest occurrence was in the mandibular first molar region, with 29 on the right side and 26 on the left side (48.6% in total). The mandibular second premolar area accounted for 20 lesions, of which 12 were on the left and 8 on the right side (17.7% in total). All four maxillary DBIs were on the left side, three in the region of the second premolar and one in the first molar region. Eleven DBIs (9.7%) had resorbed the roots of teeth, with 10 of 11 associated with the roots of the mandibular first permanent molar. Fig. 4 shows the teeth affected, with the left mandibular first molar most frequently affected. Follow-up radiographs are generaily not indicated unless there is a doubtful diagnosis or a need to follow the resorption of a tooth. A small number of patients had serial radiographs that illustrated the progress over time. In younger patients, the entity increased in radiopacity and then no further change occurred (Fig. 5). In older patients a “mature” DBI seemed to change little over time (Fig. 6). DlSCUSSlON
Many synonyms are in use for this entity, and 1 am suggesting the adoption of the term dense bone island as alternative terminology. The sample of 107 patients was selected on the basis of the presence of a
ORAL SURGERY EL MEDICINE ORAL PATHOLOGY Volume 76, Number 1
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127
Fig. 5. Panoralmic radiogralph of male patient at 10 years (A) and 16 years (I&) shows development of large DBI.
Fig. 6. Radiographs of female patient shows minimal change over 1l-years. A, 1978; B, 1980; C, 1989.
DBI and therefore cannot be considered representative of the population at large. The findings agree with previous reports that DBI occurs primarily in the first molar region of the mandible, although Geist and
Katz4 showed the highest occurrence in the second premolar region. Table II illustrates some comparisons of patients from this survey with three other reports. When all
ORAL SURCERY ORAL MEDICINE ORAL PATHOLOGY
McDonnell
July
reports are combined, the mandibular first molar region is the most common site of occurrence, with little difference between the second molar and premolar region. Farman et a1.3found little difference between the incidence in women and men. Geist and Katz4 showed a woman to man ratio of 1.5: 1) whereas the present study has a woman to man ratio of 2: 1. Farman et al3 and Geist and Katz” made no mention of resorption of the roots of teeth, whereas Eversole et al.” and this report show resorption occurring in 10% to 12% of patients. The average age of subjects was 36.0 years, but the condition had probably been present for some time before discovery. Although the number of patients with serial radiographs is small, it would tend to suggest that DBI develop in late teenage years and once mature, little if any change occurs. This might infer a slightly higher incidence in an older age group. This sample is small and not representative of the population to confirm or deny this theory. Thanks to Dr. Colin Price for his encouragement and support and being a reviewer of the radiographs in this survey. Mr Harold Traegar photographed the illustrations. This survey could not have been completed without the help of the many dentists and students who submitted radiographs and information on their patients. REFERENCES 1. Poyton HG, Pharoah MJ. Oral radiology, 2nd ed. Toronto: B.C. Decker, 1989;156-9. 2. Miles DA, Van Dis M, Kaugers GE, Lovas JGL. Oral and maxillofacial radiology: radiologic/pathologic correlations. Philadelphia: W.B. Saunders, 1991;125-9. 3. Farman AG, Joubert JJDeV, Nortje CJ. Focal ostesclerosis and apical periodontal pathoses in “European” and Cape Coloured dental outpatients. Int J Oral Surg 1978;7:549-79. 4. Geist JR, Katz JO. The frequency and distribution of ideo-
9. 10. 11. 12. 13.
14.
15. 16. 17. 18. 19. 20.
1993
pathic osteosclerosis. ORAL SURF ORAL MED ORAL PATHOL 1990;69:388-93. Gibilisco JA, ed. Stafne’s oral radiographic diagnosis, 5th ed. Philadelphia: W.B. Saunders, 1985;142-6. Goaz PW, White SC. Oral radiology: principles and interpretation. St Louis: C.V. Mosby, 1982;413-4. Wood NK, Goaz PW. Differential diagnosis of oral lesions, 3rd ed. St Louis: C.V. Mosby, 1985;§67-70. Langland OE, Langlais RP, Morris CR. Principles and practice of paroramic radiology. Philadelphia: W.B. Saunders, 1982;339. Thunty KH. Dental radiographic diagnosis. Springfield, Illinois. Charles C Thomas. 198X:1 16-9. Eversole LR. Clinical outline of oral pathology: diagnosis and treatment. Philadelphia: Lea & Febiger. 1978;227-8. Eversole LR, Stone CE, Strub D. Focal sclerosing osteomyelitis/focal periapical osteopetrosis: radiographic patterns, ORAL SURGORAL MED ORAL PATHQL 1984;58:456-60. Regezi JA, Sciubba JJ. Oral pathology: clinical-pathologic correlations. Philadelphia: W.B. Saunders, 1989;402-4. Worth HM. Principles and practice of oral radiologic interpretation. Chicago: Year Book Medical Publishers, 1963;26774. Miles DA. Contemporary maxillofacial imaging. In: Westesson PL, ed. Oral and Maxillofacial Surgery Clinics of North America. Philadelphia: W.B. Saunders, 1992;208. Shafer WG, Hine MK, Levy BM. A textbook of oral pathology, 4th ed. Philadelphia: W.B. Saunders, 1983;502-5. Kasle MJ. An atlas of dental radiographic anatomy, 3rd ed. Philadelphia: W.B. Saunders, 1989;66-7. Weine FS. Endodontic therapy, 4th ed. St. Louis: CV Mosby, 1989;161. Ingle JI, Taintor JF. Endodontics, 3rd ed. Philadelphia: Lea & Febiger, 1985;476. Cohen S, Burns RC. Pathways of the pulp, 5th ed. St. Louis: Mosbv-Year Book. 1991:366. Keats”TE. An atlas’of normal roentgen variants that may simulate disease, 2nd ed. Chicago: Year Book Medical Publishers, 1979;176,188,274.
Reprint requests: Donal McDonnell Division of Oral Radiology Faculty of Dentistry The University of British Columbia 2199 Wesbrook Mall Vancouver, BC, Canada V6T 123
OF ORAL
BDS, FFDRCSI, RADIOLOGY,
MSca Vancouver, British Columbia, Canada
FACULTY
OF DENTISTRY,
THE
UNIVERSITY
OF BRITISH
COLUMBIA
The dense bone island is an asymptomatic radiopacity of unknown origin and is known under many synonyms when it occurs in the jaw. This article discusses 113 dense bone islands in 107 patients with a review of the literature and comparison with previous reports. The average age of the patient at discovery was 36 years with a women to men ratio of 2:l. The mandible was involved in 109 of the 113 DBls, with only 4 in the maxilla. The most common site affected was the mandibular first molar region, the premolar region was the second most common site affected. Resorption occurred in 11 (9.7%) cases, the first permanent molar was the most commonly affected. (ORAL SURC ORAL MED ORAL PATHOL 1993;76:124-8)
The entity, dense bone island (DBI), may be described as a localized area of radiopacity of unknown origin that is not attributable to any other condition. Fig. 1 illustrates examples of this entity, both related and unrelated to the roots of teeth. The condition is usually asymptomatic and discovered on a radiograph taken for some other reason. The radiopacity is of variable size, shape, outline, and density. It may be associated with the roots of teeth or be totally separated by normal trabecular bone. When a DBI occurs in the tooth-bearing area of the jaw, many synonyms are used as indicated in Table I. Poyton and Pharoah’ and Miles et al.2 mention DBI but most references use the terms osteosclerosis,2-9 osteopetrosis,‘0-‘2 condensing osteitis,13 and enostosis.5,6, l3 Worth13 describes this condition as condensing or sclerosing osteitis, but most authorities differentiate between osteitis and DBI. Condensing osteitis, also known as inflammatory sclerosis, is generally considered to be a lesion of inflammatory origin and associated with a nonvital tooth, with an area of radiolucency between the radiopacity and the root.2, 5,6-9,14,l5 Others16-‘9 use the terms osteosclerosis and osteitis interchangeably. The many synonyms used, as well as the difference in interpretation of terminology, can make for confusion and difficulty in the literature. Keats20 indicates that bone islands are variations of normality and shows examples in the first lumbar vertebra, iliac bone, and the capitate and lunate bones of the hand. There have been few surveys on this condition in the literature. Farman et al.3 compared the incidence in “Europeans” with Cape Coloured. They found no difference between men and women; no difference Copyright @ 1993 by Mosby-Year Book, 0030-4220/93/$1.00 + .lO 7/16/43992
Inc.
between patients under or over 25 years of age, and equal proportion of both races affected with lesions associated with noncarious restored teeth. The most common site in both races was the mandibular first molar region. Geist and Katz4 examined the radiographs of 192 1 patients and reported an incidence of 5.4%. They found no difference between women and men, the ratio of women to men was 1.5:1 and a significantly higher frequency among black females. The most common site affected was the mandibular premolar region. Eversole et al.” discussed the radiographic patterns in 41 patients for which histopathologic confirmation was available. Histologically there is dense lamellar bone and small marrow channels. Inflammatory cell infiltration is generally lacking. The most common site affected was the mandibular first molar region, and five radiographic patterns were described. There is no known cause, and no treatment is indicated. It has been suggested that excess occlusal stress can be a factor in DBI associated with the roots of teeth.7, l1 Retained primary roots have also been implicated as a cause,6 but this could not account for DBIs on the distal aspect of the primary dentition. Generally the term idiopathic is used as a definite cause that cannot be identified. It is important to distinguish DBI from other conditions, such as periapical cemental dysplasia, submandibular calculus, torus, exostosis, osteoma, odontome, or condensing osteitis (inflammatory sclerosis) related to nonvital teeth, as the treatment is different. This study reviews the radiographs of 107 patients, all of whom had asymptomatic radiopacities that could not be attributed to any other known condition. The age and sex of the patients, as well as the distri-
ORAL SURGERYORAL MEDICINE ORAL PATHOLOGY Volume
76. Number
McDonnell
125
1
Fig. 1. Examples of densebone islands. A, DBI related to lower right first molar. B, DBI below lower right first molar. C, DBI below and between noncarious lower left tirst and secondmolar and extending to alveolar crest. D, Example in edentulous left maxilla. E, Part of panoramic radiograph shows two DBI in right canine and premolar region. F, DBI associatedwith resorbed distal root of lower right first molar.
bution by location is outlined. The results are compared with previous reports. MATERIAL AND METHODS This survey included 107 patients gathered from the files of current patients under treatment at the Faculty of Dentistry at the University of British Columbia and from general dentists in the Province of British Columbia who submitted cases. In the mandible, only radiopacities above the inferior alveolarcanal were considered. The radiopacity could be tooth related or separated from the lamina dura by normal trabecular pattern. The following criteria were used for inclusion in the survey: 1. a well-defined area of radiopacity in the toothbearing ‘arlea of the jaw 2. nio surrounding radiolucent space 3. not typical of any other condition The following criteria were used for exclusion from the survey: 1. radiopacities in the maxilla considered to be in the maxillary sinus 2. if clinical examination showed an exostosis or the presence of a torus in the area of the DBI
Table
I. Synonyms for dense bone island Osteosclerosis2-9 Condensing osteitis13 Bone eburnation7 Bone scar*, l2 Osteopetrotic scarlo
Table
Osteopetrosis*a ‘O-‘* Enostosis’x 2,5%6,7,13 Sclerotic bone62l2 Socket sclerosi& 8, 9 Bone whorl’
II. Comparisons from various surveys
No. of patients No. of DBI Women Men No. in mandible No. in maxilla First molar Second molar Premolars Resorption One DBI Two DBI
Farman et aL3 (“/oi
Eversole et al.” (%o)
Geist and Katz4 (%)
McDonnell (%I
252 392 302 90 116 61 13 -
41 41 41 0 23 8 9 5 41 0
103 112 61 42 100 12 20 36 105 7
107 113 72 (67) 35 (33) 109 (96) 4 (4) 54 (49) 13 (12) 27 (24) 11 (10) 101 (94)
(77) (23) (30) (16) (3)
(100) (0) (56) (20) (22) (12) (100) (0)
(59) (41) (89) (11) (21) (32) (94) (6)
Percentages have been rounded to the nearest full percent.
6 (6)
s126; McDonnell
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY July 1993
46
36
37
TCJQth Fig. 4. Histogram illustrates presenceof resorption associated with molar teeth. M + D = mesial and distal roots, M = mesial root only, D = distal root only. Fig. 2. Histogram illustrates agerange of 99 patients. Age was not known in 8 patients.
Fig. 3. Histogram illustrates distribution of DBI in mandible. 3. if symptoms were present in the area of the DBI Two observers reviewed the radiographs and agreed on the radiographic diagnosis. If there was any disagreement or doubtful diagnosis, the patient was excluded from the survey. Information relating to site, sex, age, race, and presence of resorption was recorded. RESULTS A total of 107 patients with 113 DBIs were included in the study; 101 patients had one DBI and six patients had two DBI. Seventy-two patients were women (67.3%) and 35 were men (32.7%), which is a woman to man ratio of 2: 1.
Age was known in 99 patients and, at the time of the discovery of the DBIs, ranged from I2 to 83 years, with a mean age of 36.0 years (Fig. 2). The race was known in 92 patients (84%) and was distributed as follows: white, 76 (7 1.O%); Orientals, 15 ( 14.0%); and black, 1 ( 1.O%). Of the 113 lesions, 109 were present in the mandible (96.5%), with only 4 (3.5%) in the maxilla. Fig. 3 shows the distribution in the mandible, with no radiopacities present in the central incisor region. The highest occurrence was in the mandibular first molar region, with 29 on the right side and 26 on the left side (48.6% in total). The mandibular second premolar area accounted for 20 lesions, of which 12 were on the left and 8 on the right side (17.7% in total). All four maxillary DBIs were on the left side, three in the region of the second premolar and one in the first molar region. Eleven DBIs (9.7%) had resorbed the roots of teeth, with 10 of 11 associated with the roots of the mandibular first permanent molar. Fig. 4 shows the teeth affected, with the left mandibular first molar most frequently affected. Follow-up radiographs are generaily not indicated unless there is a doubtful diagnosis or a need to follow the resorption of a tooth. A small number of patients had serial radiographs that illustrated the progress over time. In younger patients, the entity increased in radiopacity and then no further change occurred (Fig. 5). In older patients a “mature” DBI seemed to change little over time (Fig. 6). DlSCUSSlON
Many synonyms are in use for this entity, and 1 am suggesting the adoption of the term dense bone island as alternative terminology. The sample of 107 patients was selected on the basis of the presence of a
ORAL SURGERY EL MEDICINE ORAL PATHOLOGY Volume 76, Number 1
McDonnell
127
Fig. 5. Panoralmic radiogralph of male patient at 10 years (A) and 16 years (I&) shows development of large DBI.
Fig. 6. Radiographs of female patient shows minimal change over 1l-years. A, 1978; B, 1980; C, 1989.
DBI and therefore cannot be considered representative of the population at large. The findings agree with previous reports that DBI occurs primarily in the first molar region of the mandible, although Geist and
Katz4 showed the highest occurrence in the second premolar region. Table II illustrates some comparisons of patients from this survey with three other reports. When all
ORAL SURCERY ORAL MEDICINE ORAL PATHOLOGY
McDonnell
July
reports are combined, the mandibular first molar region is the most common site of occurrence, with little difference between the second molar and premolar region. Farman et a1.3found little difference between the incidence in women and men. Geist and Katz4 showed a woman to man ratio of 1.5: 1) whereas the present study has a woman to man ratio of 2: 1. Farman et al3 and Geist and Katz” made no mention of resorption of the roots of teeth, whereas Eversole et al.” and this report show resorption occurring in 10% to 12% of patients. The average age of subjects was 36.0 years, but the condition had probably been present for some time before discovery. Although the number of patients with serial radiographs is small, it would tend to suggest that DBI develop in late teenage years and once mature, little if any change occurs. This might infer a slightly higher incidence in an older age group. This sample is small and not representative of the population to confirm or deny this theory. Thanks to Dr. Colin Price for his encouragement and support and being a reviewer of the radiographs in this survey. Mr Harold Traegar photographed the illustrations. This survey could not have been completed without the help of the many dentists and students who submitted radiographs and information on their patients. REFERENCES 1. Poyton HG, Pharoah MJ. Oral radiology, 2nd ed. Toronto: B.C. Decker, 1989;156-9. 2. Miles DA, Van Dis M, Kaugers GE, Lovas JGL. Oral and maxillofacial radiology: radiologic/pathologic correlations. Philadelphia: W.B. Saunders, 1991;125-9. 3. Farman AG, Joubert JJDeV, Nortje CJ. Focal ostesclerosis and apical periodontal pathoses in “European” and Cape Coloured dental outpatients. Int J Oral Surg 1978;7:549-79. 4. Geist JR, Katz JO. The frequency and distribution of ideo-
9. 10. 11. 12. 13.
14.
15. 16. 17. 18. 19. 20.
1993
pathic osteosclerosis. ORAL SURF ORAL MED ORAL PATHOL 1990;69:388-93. Gibilisco JA, ed. Stafne’s oral radiographic diagnosis, 5th ed. Philadelphia: W.B. Saunders, 1985;142-6. Goaz PW, White SC. Oral radiology: principles and interpretation. St Louis: C.V. Mosby, 1982;413-4. Wood NK, Goaz PW. Differential diagnosis of oral lesions, 3rd ed. St Louis: C.V. Mosby, 1985;§67-70. Langland OE, Langlais RP, Morris CR. Principles and practice of paroramic radiology. Philadelphia: W.B. Saunders, 1982;339. Thunty KH. Dental radiographic diagnosis. Springfield, Illinois. Charles C Thomas. 198X:1 16-9. Eversole LR. Clinical outline of oral pathology: diagnosis and treatment. Philadelphia: Lea & Febiger. 1978;227-8. Eversole LR, Stone CE, Strub D. Focal sclerosing osteomyelitis/focal periapical osteopetrosis: radiographic patterns, ORAL SURGORAL MED ORAL PATHQL 1984;58:456-60. Regezi JA, Sciubba JJ. Oral pathology: clinical-pathologic correlations. Philadelphia: W.B. Saunders, 1989;402-4. Worth HM. Principles and practice of oral radiologic interpretation. Chicago: Year Book Medical Publishers, 1963;26774. Miles DA. Contemporary maxillofacial imaging. In: Westesson PL, ed. Oral and Maxillofacial Surgery Clinics of North America. Philadelphia: W.B. Saunders, 1992;208. Shafer WG, Hine MK, Levy BM. A textbook of oral pathology, 4th ed. Philadelphia: W.B. Saunders, 1983;502-5. Kasle MJ. An atlas of dental radiographic anatomy, 3rd ed. Philadelphia: W.B. Saunders, 1989;66-7. Weine FS. Endodontic therapy, 4th ed. St. Louis: CV Mosby, 1989;161. Ingle JI, Taintor JF. Endodontics, 3rd ed. Philadelphia: Lea & Febiger, 1985;476. Cohen S, Burns RC. Pathways of the pulp, 5th ed. St. Louis: Mosbv-Year Book. 1991:366. Keats”TE. An atlas’of normal roentgen variants that may simulate disease, 2nd ed. Chicago: Year Book Medical Publishers, 1979;176,188,274.
Reprint requests: Donal McDonnell Division of Oral Radiology Faculty of Dentistry The University of British Columbia 2199 Wesbrook Mall Vancouver, BC, Canada V6T 123