Complex odontoma as a periapical and interradicular radiopacity in a primary molar.

Only rarely is a mature complex odontoma seen in a periapical location and in association with a primary tooth. Complex odontomas usually present as a radiopacity with a radiolucent rim. The differential diagnosis must include mature fibro-osseous lesions (e.g. cementoblastoma). Complex odontomas can be differentiated from fibro-osseous lesions because they usually present a nonhomogeneous radiopacity and almost always will present as solitary lesions. For complex odontomas located in the periapical region, the differential diagnosis must include idiopathic periapical osteosclerosis. In this case, the presence of the radiolucent rim and the presence of denser, sharper radiopacities produced by enamel distinguish the odontoma.