A Giant Compound Odontome in Posterior Mandible

INTRODUCTION

Odontomas are non-aggressive, hamartomatous developmental malformations or lesions of odontogenic origin, which consists of enamel, dentin, cementum and pulpal tissue. These lesions are composed of more than one type of tissue and for this reason, have been called as composite odontomas.¹ The World Health Organization has subdivided odontomas into a compound and complex type based on histologic criteria. Compound odontomas consist of multiple miniature or rudimentary teeth, whereas complex odontomas appear as an amorphous and disorderly pattern of calcified dental tissues. The etiology is not clear, although local trauma, infection and genetic factors have been suggested as possible causes ². Odontomas show no gender predilection. Odontomas are usually detected in school-age children, and the mean age at the time of diagnosis is 14 years ^3,4. The majority of odontomas are asymptomatic and seldom causes swelling, pain, suppuration, bony expansion, and displacement of teeth^3,5. These lesions are commonly small, seldom larger than a tooth. Odontomas are generally discovered through routine radiographic examination in dental treatment. An odontoma is essentially a benign lesion, but, often causes disturbances in the eruption of its associated tooth.^6,7. Odontomas mostly occur in the permanent dentition and are rarely associated with the primary teeth ^5,8,9. Compound odontomas are more prevalent than complex odontomas. Compound odontomas commonly occur in the incisor-canine region of the maxilla and complex odontomas are frequently located in the premolar and molar region of both jaws¹⁰. Odontomas occur more often in the permanent dentition. An unusual association of odontomas with primary dentition was reported¹¹.

We report a rare case of huge compound odontome with dentigerous cyst lining in the posterior mandible, which was treated surgically. The unusual site of occurrence, compound odontome in the posterior mandible and most importantly its huge size and association with a dentigerous cyst lining makes it worth presenting.

CASE REPORT

A 14 yrs old male patient had come to the Oral Surgery Department with a chief complaint of swelling over right lower 3rd of face since 1 month.

The patient was healthy with an unremarkable medical history. Patient gives history of trauma due to fall when patient was 8 months old for which he was treated by medicines

Extraoral examination revealed A Single, well defined, hard, tender, non warm, non fluctuant swelling present at right body region of mandible, extending anteroposteriorly from corner of mouth to 1 cm in front of posterior border of mandible and superoinferiorly from an ala-tragus line to the lower border of mandible. Right submandibular lymphnodes are enlarged, tender and palpable.

Intraoral examination revealed A Single, well defined , localized, hard, tender swelling extending from Lower right deciduous canine to anterior border of right ramus of mandible with obliteration of right buccal vestibule. Buccal and lingual cortical plate expansion present. Clinically missing lower right permanent canine, 2nd premolar and 1st & 2nd molar

Similar swelling appeared before 1 year, for which patient had taken medication from private clinic and got relief. But again swelling reappeared before 1 month and doesn’t subsided with medicine. O.P.G. revealed a a single, well defined, bilocular radioopacity with surrounding radioluscent periphery extending from right lower deciduous canine, posteriorly into the ramus with thinning of lower border of mandible alongwith impacted lower right permanent canine, 2nd premolar and 1st & 2nd molar

The differential diagnosis of the mixed radiopac-radiolucent picture included gient complex odontoma, ameloblastic fibro-odontoma, odotoameloblastoma and cystic calcified odontogenic tumor and benign cementoblastoma. Complete surgical removal of the calcified tissue was done under genral anesthesia and subjected to histopathological examination. Sections stained with Hematoxylin and Eosin showed the presence of dentinal structures along with few cementum like structures with presence of a cystic lining. The cystic lining consists of two to three rows of cubiodal epithelium originating from the surrounding fibrous tissue, resembling dentigerous cyst.

Fig 1: Frontal view, showing swelling over right side of face

Fig 2: Pre operative X-ray OPG

Fig 3: Intra operative view of empty bony cavity

Fig 4: Resected bony mass

Fig 5: Post operative X-ray OPG

Fig 6: Histopathologic view

DISCUSSION

The term ‘odontoma’ (or odontome) which was firstly described by Paul Broca in 1867, was originally used as a general descriptive for any tumour (in its broadest sense) of odontogenic origin.¹² Broca defined the term as ‘tumours which were formed by the overgrowth or the transitory of the complete dental tissue’.¹³ Odontomas are non-aggressive, hamartomatous developmental malformations or lesions of odontogenic origin appearing as small, solitary or multiple radioopaque lesions found on routine radiographic examinations. They are the most common odontogenic tumours which constitute 22% of all the odontogenic tumours of the jaws¹⁴. Although odontomas may be found in any tooth bearing region of the jaws, Compound odontomas show a prediliction in the anterior section of the upper maxilla, while complex odontomas are typically found in the posterior mandibular region ^15,16.. In contrast to these data in our case compound odontome located in posterior mandibular region which is quite rare condition. Any trauma during the stage of odontogenesis can seriously affect the morphogenetic stages of dental development, and several developmental alterations can arise in permanent teeth as a consequence of dental injuries and maxillofacial traumas. Odontoma-like malformations and partial or complete arrest of root formation are rare complications developed after trauma. The extent of these malformations depends on the permanent tooth’s developmental stage. Odontomas can also manifest as part of syndromes, such as basal cell nevus syndrome, Gardner syndrome, familial colonic adenomatosis, Tangier disease or Hermann syndrome^14,17. Dentigerous cyst arising from the fibrous connective tissue lining of the compound odontome is rare¹. Though cases of Complex odontomas associated with dentigerous cyst were reported¹⁸. The present case also showed dentigerous cyst arising from fibrous connective tissue lining of the compound odontome. The present case is rare because of posterior mandibular localization, such a huge size and occurrence of surrounding dentigerous cyst in compound odontome.

CONCLUSION

Dentigerous cyst arising from the fibrous connective tissue lining of the odontome is rare. If arise, they are potential for attaining large size, tooth resorption, destruction of jaw bones and some shows neoplastic changes like ameloblastoma. The potential complication justifies radiographic screening, histopathological evaluation and complete enucleation of all the odontomes.

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