Odontoma

Odontomas are the most common odontogenic tumors, accounting for almost 50% of all cases. Although, they are referred to as neoplasms, they behave more like odontogenic hamartomas rather than neoplasms. Odontomas are of compound and complex types. The compound type is characterized by the formation of multiple small, malformed tooth-like structures. All of the tissues that comprise a tooth, including enamel and dentin matrix and dental soft tissues, are present and are assembled in the form of imperfect caricatures of teeth. In the complex odon-toma, the same tissues are present but in a tangled mass that bears no resemblance to teeth. The distinction is arbitrary since there are hybrid lesions exhibiting mixtures of the two and there is no difference in behavior. It is argued that the compound odontoma is a true hamartoma whereas the complex type is the end stage of the maturation of an ameloblastic fibroma. The issue is of academic interest only. Odontomas are found in aft regions of both jaws and most are recognized before age 20. They cause no symptoms and are discovered on radiographs taken in the course of routine dental care. Because they occur during the time of life when teeth are forming and erupting, they may impair these activities. It is common to find an impacted but otherwise normal tooth in the vicinity of an odontoma. Most odontomas are recognizable radiographically. This is especially true of compound odontomas. Multiple small dense bodies resemble a "bag of marbles.'' Complex odontoma does not have this identifying characteristic and removal for microscopic examination may be required to rule out other bone tumors. Odontomas may be associated with a cyst. The cyst may be mundane and lined by simple squamous epithelium, but there are a number of reports of odontoma associated with the calcifying odontogenic cyst. Approximately 15% of odontomas will be found to have ghost cells of the type encountered in the calcifying odontogenic cyst but no cyst is present. Removal is elective. These tumors seem to have a predetermined size and when this size is attained, growth ceases. Tumors that do no harm to adjacent structures or do not occupy needed space may be followed radiographically and removed it there is change, which is unlikely.

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