Radiology forum Each month this section will bring to the reader of ORAL SURGERY, ORAL MEDICINE, AND ORAL PATHOLOGY information of practical relevance to the art and science of diagnostic imaging and diagnostic images with unusual interpretive features. Practical notes and radiographs will be accompanied by an explanation or inquiry. Please submit 5 X 7 inch glossy black-and-white prints of your illustrations. All materials for publication should be submitted to Dr. Allan G. Farman, Division of Radiology and Imaging Sciences, Department of Biological and Physical Sciences, School of Dentistry, University of Louisville, Louisville, KY 40292.
DISPLACED
TEETH!
expects teeth to be examined by a 0dentist;ne generally however, this patient (Fig. 1) had 17 perfectly formed teeth “inspected” by her gynecologist. This is a case of ovarian teratoma, a not infrequent site for supernumerary teeth in women.
Bruce L. Douglas, DDS 2401 Dufly Lane Riverwoods, IL 60015
DEVELOPMENTAL LINGUAL MANDIBULAR RAMUS
P
DEFECTS
view demonstrates ovarian ter-
ON THE
osterior lingual cortical defects of the mandible, frequently referred to as Stafne’s idiopathic bone cavities, or lingual bone depressions, are common radiographic findings. l-6 These benign developmental defects, ranging from 2 to 18 mm in diameter (dry bone dimensions) are found primarily in adult males and are located in the retromolar region, inferior to the mylohyoid ridge. Conversely, bone defects in the mandibular ramus are rare radiographic findings that have been previously reported in only five pers0ns.l We examined 6300 human mandibles of both sexes and all ages, housed at the Smithsonian Institution. These skeletal samples representing groups from North, Central, and South America; Egypt; Siberia; 124
Fig. 1. Anterior-posterior atoma.
and Europe revealed 115 adults with idiopathic bone cavities (104 male), three adults with defects in the
mandibular sulcus, and two adults with defects high on the dorsal part of the ramus. The latter two defects are the subject of this report. Case reports
The subjectsof our study were Alaskan Eskimomales who died in the 1800s.The younger, 25 to 35 yearsof age (No. 372892)had all histeeth andshowedonly mild dental attrition and no cariouslesions.The older male,who died at age40 to 50 years(No. 339058) had severedental attrition andantemortemlossof the mandibularright molars. The lingual depression in the youngermale(Fig. 1) measured5 X 3 X 2 mm(maximumlength, breadth,anddepth
Volume 74 Number 1
Radiology forum
125
Fig. 1. Photograph of small lingual defect in 25- to 3% year-old male mandible.
Fig. 3. Photograph of large lingual defect in 40- to 50year-old male mandible.
Fig. 2. Radiograph of lingual defect in younger male.
Fig. 4. Radiograph of lingual defect in older male (note lack of sclerosis).
measured from the bone), with a gently sloping and a welldefined margin with no radiographic evidence of sclerosis. The floor of the depression was conoidal and appeared to be normal cortical bone that had migrated buccally. The defeet was ovoidal and oriented superioinferiorly. A 3.5 mm
section of bone separates the defect from the posterior margin of the ramus. The defect in the older male (Fig. 2) measured 12 X 7 x 3 mm. This defect was also ovoidal and oriented with its long axis superioinferiorly. The margin of the depression was
126
Radiology forum
ORAL SURG ORAL MEW ORAL PATHOL July 1992
sharply defined, its walls were undercut but continuous, and the lingual cortex was eroded nearly to the extent of perforating the buccal plate. A 1.5 mm portion of bone separated the posterior margin of the defect and the most posterior margin of the ramus. There was no radiographic evidence of sclerosis. Discussion
Lingual cortical defects of the mandible are usually classified under one of two categories: anterior and posterior defects. Anterior defects are situated inferior to the incisor and premolar region, and posterior defects are always in the retromolar area, inferior to the mylohyoid ridge. A search of the literature revealed only one report of bone cavities situated high on the mandibular ramus, cavities similar to those reported here.7 The ovoidal defects (i.e., bone cavities or lucencies) were found in five Finnish men (mean age 46 years) during routine radiographic examination. Three of the defects were on the left mandibular ramus and two were on the right. Radiographically the defects ranged in size from 7 X 3 mm to 1.5 X 7 mm, and four defects were surrounded totally or partially by a dense radiopaque line. Follow-up examinations for up to 6 years 4 months revealed that none of the patients had symptoms and no changes were observed in the size or circumference of the defects. We concluded that the location and radiographic appearance of these asymptomatic defects near the parotid gland supported the theory that developmental bone cavities are salivary gland depressions of bone. In conclusion, the two lingual defects presented here are radiographically similar in appearance and location to the five cases reported by Wolf.7 The present defects are situated near the parotid gland,
lack evidence of sclerosis or inflammation,
and grossly
resemble developmental bone cavities (Stafne’s) commonly seen in the retromolar region. To date, lingual defects on the mandibular ramus have only been found in men. The absence of similar defects in children supports the hypothesis that the defects are developmental and not congenital. We hope that other researchers may have encountered similar defects and can offer insight regarding their cause, frequency, and sex-relatedness in modern and ancient populations, Robert W. Mann, MA Anne Keenleyside, MA Department of Anthropology Smithsonian Institution NHB, Mail Stop I 12 Washington, DC 20560 Department of Anthropology MeMaster University Hamilton, Canada REFERENCES 1. Correll RW, Jensen JL, Rhyne RR. Lingua1 cortical mandibular defects. ORAL SURC ORAL MED ORAL PATHOL 1980:50: 287-91. 2. Chen CY, Ohba T. An analysis of radiological findings of Stafne’s idiopathic bone cavity. Dentomaxillofac Radio1 1981;10:18-23. 3. Shiratsuchi Y, Tashiro H, Yuasa K, Kanda S. Posterior lingua1 mandibular bone depression. Int J Oral Maxillofac Surg 1986;15:98-101. 4. Smith NJD, Looh FC, Todd JM, Whaites EJ. Stafne’s bone cavity: a review of the literature and report of two cases. Clin Radio1 1985;36:297-9. 5. Simpson W. A Stafne’s mandibular defect containing a pleomorphic adenoma: report of case. J Oral Surg 1965;23:553-6. 6. Pogrel MA, Sanders K, Hansen LS. Idiopathic lingual mandibular bone “depression”. Int J Oral Maxillofac Surg 1986; 15:93-7. 7. Wolf J. Bone defects in mandibular ramus resembling developmental bone cavity (Stafne). Proc Finn Dent Sot 1985;8 I : 215-21.
IMPACTED MANDIBULAR SECOND MOLAR
29-year-old white man was referred by his denA tist to our department for evaluation of unerupted molars. Clinical examination revealed the right and
left mandibular third molars to be partially bony impacted. Panoramic radiography showed the right mandibular second molar to be horizontally impacted and in close proximity to the mandibular canal (Fig. 1). This was confirmed by coronal computed tomographic scans,which better illustrated the buccolingual relationship of the impacted teeth to the mandibular canal (Fig. 2).
Fig. 1. Panoramicradiographshowshorizontally i secondmolar near mandibularcanal.
DISPLACED
TEETH!
expects teeth to be examined by a 0dentist;ne generally however, this patient (Fig. 1) had 17 perfectly formed teeth “inspected” by her gynecologist. This is a case of ovarian teratoma, a not infrequent site for supernumerary teeth in women.
Bruce L. Douglas, DDS 2401 Dufly Lane Riverwoods, IL 60015
DEVELOPMENTAL LINGUAL MANDIBULAR RAMUS
P
DEFECTS
view demonstrates ovarian ter-
ON THE
osterior lingual cortical defects of the mandible, frequently referred to as Stafne’s idiopathic bone cavities, or lingual bone depressions, are common radiographic findings. l-6 These benign developmental defects, ranging from 2 to 18 mm in diameter (dry bone dimensions) are found primarily in adult males and are located in the retromolar region, inferior to the mylohyoid ridge. Conversely, bone defects in the mandibular ramus are rare radiographic findings that have been previously reported in only five pers0ns.l We examined 6300 human mandibles of both sexes and all ages, housed at the Smithsonian Institution. These skeletal samples representing groups from North, Central, and South America; Egypt; Siberia; 124
Fig. 1. Anterior-posterior atoma.
and Europe revealed 115 adults with idiopathic bone cavities (104 male), three adults with defects in the
mandibular sulcus, and two adults with defects high on the dorsal part of the ramus. The latter two defects are the subject of this report. Case reports
The subjectsof our study were Alaskan Eskimomales who died in the 1800s.The younger, 25 to 35 yearsof age (No. 372892)had all histeeth andshowedonly mild dental attrition and no cariouslesions.The older male,who died at age40 to 50 years(No. 339058) had severedental attrition andantemortemlossof the mandibularright molars. The lingual depression in the youngermale(Fig. 1) measured5 X 3 X 2 mm(maximumlength, breadth,anddepth
Volume 74 Number 1
Radiology forum
125
Fig. 1. Photograph of small lingual defect in 25- to 3% year-old male mandible.
Fig. 3. Photograph of large lingual defect in 40- to 50year-old male mandible.
Fig. 2. Radiograph of lingual defect in younger male.
Fig. 4. Radiograph of lingual defect in older male (note lack of sclerosis).
measured from the bone), with a gently sloping and a welldefined margin with no radiographic evidence of sclerosis. The floor of the depression was conoidal and appeared to be normal cortical bone that had migrated buccally. The defeet was ovoidal and oriented superioinferiorly. A 3.5 mm
section of bone separates the defect from the posterior margin of the ramus. The defect in the older male (Fig. 2) measured 12 X 7 x 3 mm. This defect was also ovoidal and oriented with its long axis superioinferiorly. The margin of the depression was
126
Radiology forum
ORAL SURG ORAL MEW ORAL PATHOL July 1992
sharply defined, its walls were undercut but continuous, and the lingual cortex was eroded nearly to the extent of perforating the buccal plate. A 1.5 mm portion of bone separated the posterior margin of the defect and the most posterior margin of the ramus. There was no radiographic evidence of sclerosis. Discussion
Lingual cortical defects of the mandible are usually classified under one of two categories: anterior and posterior defects. Anterior defects are situated inferior to the incisor and premolar region, and posterior defects are always in the retromolar area, inferior to the mylohyoid ridge. A search of the literature revealed only one report of bone cavities situated high on the mandibular ramus, cavities similar to those reported here.7 The ovoidal defects (i.e., bone cavities or lucencies) were found in five Finnish men (mean age 46 years) during routine radiographic examination. Three of the defects were on the left mandibular ramus and two were on the right. Radiographically the defects ranged in size from 7 X 3 mm to 1.5 X 7 mm, and four defects were surrounded totally or partially by a dense radiopaque line. Follow-up examinations for up to 6 years 4 months revealed that none of the patients had symptoms and no changes were observed in the size or circumference of the defects. We concluded that the location and radiographic appearance of these asymptomatic defects near the parotid gland supported the theory that developmental bone cavities are salivary gland depressions of bone. In conclusion, the two lingual defects presented here are radiographically similar in appearance and location to the five cases reported by Wolf.7 The present defects are situated near the parotid gland,
lack evidence of sclerosis or inflammation,
and grossly
resemble developmental bone cavities (Stafne’s) commonly seen in the retromolar region. To date, lingual defects on the mandibular ramus have only been found in men. The absence of similar defects in children supports the hypothesis that the defects are developmental and not congenital. We hope that other researchers may have encountered similar defects and can offer insight regarding their cause, frequency, and sex-relatedness in modern and ancient populations, Robert W. Mann, MA Anne Keenleyside, MA Department of Anthropology Smithsonian Institution NHB, Mail Stop I 12 Washington, DC 20560 Department of Anthropology MeMaster University Hamilton, Canada REFERENCES 1. Correll RW, Jensen JL, Rhyne RR. Lingua1 cortical mandibular defects. ORAL SURC ORAL MED ORAL PATHOL 1980:50: 287-91. 2. Chen CY, Ohba T. An analysis of radiological findings of Stafne’s idiopathic bone cavity. Dentomaxillofac Radio1 1981;10:18-23. 3. Shiratsuchi Y, Tashiro H, Yuasa K, Kanda S. Posterior lingua1 mandibular bone depression. Int J Oral Maxillofac Surg 1986;15:98-101. 4. Smith NJD, Looh FC, Todd JM, Whaites EJ. Stafne’s bone cavity: a review of the literature and report of two cases. Clin Radio1 1985;36:297-9. 5. Simpson W. A Stafne’s mandibular defect containing a pleomorphic adenoma: report of case. J Oral Surg 1965;23:553-6. 6. Pogrel MA, Sanders K, Hansen LS. Idiopathic lingual mandibular bone “depression”. Int J Oral Maxillofac Surg 1986; 15:93-7. 7. Wolf J. Bone defects in mandibular ramus resembling developmental bone cavity (Stafne). Proc Finn Dent Sot 1985;8 I : 215-21.
IMPACTED MANDIBULAR SECOND MOLAR
29-year-old white man was referred by his denA tist to our department for evaluation of unerupted molars. Clinical examination revealed the right and
left mandibular third molars to be partially bony impacted. Panoramic radiography showed the right mandibular second molar to be horizontally impacted and in close proximity to the mandibular canal (Fig. 1). This was confirmed by coronal computed tomographic scans,which better illustrated the buccolingual relationship of the impacted teeth to the mandibular canal (Fig. 2).
Fig. 1. Panoramicradiographshowshorizontally i secondmolar near mandibularcanal.
