Dilated Odontoma Arising in the Mandibular Third Molar Germ: Report of a Case of an Unusual Lesion in an Uncommon Site

Abstract

Dilated odontoma is the most severe variant of dens invaginatus. It is extremely uncommon in the posterior mandible. It is thought to originate during the morpho-differentiation stage of dental development. However, its etiology and pathogenesis remain obscure. We report here the clinical and pathologic findings of an incidentally discovered dilated odontoma arising in the left third mandibular molar germ of an 11-year-old male and a review of the pertinent literature. As dilated odontoma is not established as an independent entity in the current WHO classification of odontogenic tumors and is the result of a well-established developmental anomaly of the tooth (that is, the invagination of the enamel organ into the dental papilla), it should be better identified as dilated dens invaginatus.

Dilated odontoma in the mandibular third molar region: a case report

“…The results obtained showed that Dilated Odontoma was present in the lower third molar region, which has been rarely described or cited by authors in the literature [10]. The literature [4] also mentions the rarity of dens invaginatus in the mandible, mainly citing the molar region.…”

“…Dens invaginatus (DI) is an abnormality of tooth development that results from the enfolding of the enamel organ into the dental papilla before the completion of calcification. Oehler's widely accepted classification system divides this malformation into three simple categories: class I, II, III a and b [4].…”

“…In this category, the tooth may have a circular or oval shape with a translucent center and a distinctive structure, sometimes with a central soft tissue mass. In its most severe form, it is called Dilated Odontoma [4]. In this classification, the malformation can be entirely covered by enamel or cementum, and its invagination penetrates the root, perforating the apical region.…”

“…Intraorally, variations in characteristics range from clinically defined presence of the dental element, as reported by the Authors [11], to its absence. The patient may occasionally complain of diffuse pain and discomfortt [4], which is not a mandatory condition and often occurs due to the presence of infection associated with the element. In this case, the crown morphology was clinically healthy and the diagnosis of Dilated Odontoma was initiated due to the presence of painful symptoms.…”

“…This severe variation presents as a morphologically abnormal dental element resulting in a spherical or oval calcified structure with a radiolucent central portion. Despite the presence of harmatia (defect in its development), it should not be considered as a type of odontoma (tumor) because it does not have hamartomatous growth [4].…”