Complex Odontoma Associated with Permanent Tooth – A Case Report

Abstract

Odontomas are benign tumors of odontogenic origin and are most commonly occurring tumors of the jaws. The etiology of odontoma is unknown. Depending on the extent of morphodifferentiation or their resemblance to normal teeth, odontoma can be divided into two types: the complex and the compound odontoma. Both types are composed of enamel, dentin, cementum and pulp tissues, but in complex odontomas the tissues are arranged in a haphazard fashion with no discernible dental structures, whereas in compound odontomas the dental tissues exist in a more regular pattern so that the lesion consists of tooth-like structures. We report a case of a 22-year-old male with a large complex odontoma in an impacted mandibular third molar tooth.

Introduction

Odontomas are hamartomatous lesions or malformations composed of mature enamel, dentin, and pulp. They consist of mixed lesions with epithelial and mesenchymal tissues and are usually found during a routine radiographic examination or as a factor in noneruption. The cause of the odontoma is unknown, but it is believed to be hereditary or due to a disturbance in tooth development triggered by trauma or infection.1

Case Report

A 22 year old patient visited to our department with chief complaint of pain with lower left back tooth since 4 days. Pain was moderate and continuous in nature.  Clinical examination revealed occlusal caries with 36 and 37 and unerupted 38 [Figure 1]. Intra oral periapical (IOPA) radiograph was advised and radiograph showed occlusal decay with 36 and 37 and unerupted 38 [Figure 2]. On occlusal aspect of the 38 region an amorphous radiopaque well defined mass surrounded by radiolucent band on distal aspect measuring approximately 1X 0.7 cm was seen. Radiopacity was not organized. Orthopantomograph showed erupting 18, 48 and impacted 38 with pericoronal radiopacity [Figure 3 and 4]. Considering the history and radiological findings we arrived at diagnosis of complex odontoma in 38 region.

Discussion

Odontomas are mixed tumors consisting of both epithelial and mesenchymal cells that exhibit complete dental tissue differentiation (enamel, dentin, cementum and pulp). According to 1992 World Health Organization (WHO) of odontogenic tumors, four odontogenic tumors have mixed tissue origin; ameloblastic fibroma, compound odontoma, complex odontoma and ameloblastic fibro-odontoma. They are usually detected on normal radiographic examination in second and third decades of life.

Although odontomas are typically asymptomatic, clinical indicators includes, retention of deciduous teeth, noneruption of permanent teeth, pain expansion of cortical bone, and tooth displacement. Other symptoms includes paresthesia in lower lip and swelling in the affected area. In the present case it was associated with impacted 38 with no history of paresthesia and swelling and no tooth displacement. 2,3

Odontomas are hamartomas composed of various dental tissues enamel, dentin, cementum and sometimes pulp. They are slow growing benign tumors showing non- aggressive behavior. They are classified as complex, when the calcified tissue present as an irregular mass composed mainly of mature tubular dentin or compound if there is superficial anatomic similarity to even rudimentary teeth. Complex odontomas are less common than compound in the ratio of 1:2. Complex odontomas are tend to occur in the posterior region of jaw and compound odontomas are more common in the anterior maxilla. Although they are commonly asymptomatic, clinical indicators of odontomas are retention of deciduous teeth, non eruption of permanent teeth. pain, expansion of cortical bone and tooth displacement. Other symptoms include anesthesia in the lower lip and swelling in the affected area.3,4

Despite their unknown aetiology, odontomas are usually discovered during the second and third decades of life. Odontomas occure somewhat more frequently in the maxilla than in the mandible. Compound type more often seen in the anterior maxilla and complex odontoma occure more often in the molar region of either jaw. Compound odontoma is composed of multiple small tooth like structures. The complex odontoma consist of mass of enamel and dentin which bears no anatomic resemblance to the tooth. Majority of these lesions are completely asymptomatic , being discovered on routine radiographic examination or when films are taken to determine the reason for failure  of a tooth to erupt.2,3,5

Radiographically, the compound odontoma  appears as collection of tooth like structures  of varying size and shape surrounded by narrow radiolucent zone. The complex odontoma appears as a calcified mass with radiodensity  of tooth structure which is also surrounded by narrow radiolucent rim. An unerupted tooth is frenquently associated with odontoma, and the odontoma prevent the eruption of teeth. Most odontomas (70%) are associated with abnormalities such as impaction, malpositioning, diastema, aplasia, malformation and devitalization of adjacent tooth. Large complex odontomas may cause expansion of the jaw with maintenance of the corticle boundary. Panoramic and periapical images usually show well-defined borders of a similar density to calcified dental tissue, having a ground-glass appearance, and a radiopaque mass surrounded by a thin radiolucent halo.6,7

Differential diagnosis of odontoma is not difficult, a tooth like appearance of the radiopaque structures within well defined lesion leads to easy recognition of a compound odontoma. Complex odontomas differ from cemento-ossifying fibromas (COF) by their tendency to associate with unerupted molar teeth. They are usually more radiopaque than COF. Periapical cemental dysplasia may resemble complex odontoma but are usually multiple and centered on the periapical region of the teeth. The periphery of the cemental dysplasia usually has a wider uneven sclerotic border, where as odontomas have a well -defined cortical border and usually the soft tissue capsule is more uniform and better defined with odontomas than in cemental dysplasia.1.3.5 

Histologically the compound odontoma consist of multiple structures resembling  small, single rooted teeth, contained in a loose fibrous matrix. Complex odontoma consist of clefts or hollow circular structures and small iceland of eosinophilic -staining epithelial ghost cells (20%). The ghost cell keratinization occurs as a result of metaplastic transformation. Complex odontomas contain both normal and metaplastic odontogenic epithelial cells, which may have lost their developmental and inductive properties.6,7 These lesions are easily removed under local anaesthesia and the prognosis is very good. The results achieved indicate that the early diagnosis of odontomas allows the adoption of a less complex and expensive treatment and ensures better prognosis.

References

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Ozeç I, Kiliç E, Yeler H, Göze F, Yeler D. Large complex odontoma associated with a primary tooth. Quintessence Int. 2007 Jun; 38(6):521-4.

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2. Manjol Vengal, Honey Arora et al : Large erupting complex odontoma : A case report JCDA March 2007, Vol 73, No.2.
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7. Mupparapu M, Singer SR, Rinaggio J. Complex odontoma of unusual size involving the maxillary sinus: report of a case and review of CT and histopathologic features. Quintessence Int 2004;35:641–645.

Intraoral photograph showing occlusal discoloration of 36 & 37 teeth.

IOPA showing partial view of impacted 38 with pericoronal radiopacity

Cropped OPG showing impacted 38 with pericoronal radiopacity