Odontoma

Synonym / Acronym

Compound odontoma, complex odontomas, odontogenic hamartoma.

Definition

Odontomas are composed of all mature components of dental hard and soft tissue: enamel, dentin, and pulp tissue. Because of their limited slow growth and well-differentiation, they are generally considered to represent hamartomas rather than true neoplasm.

Compound Odontoma

It is a collection of small radiopaque masses, some or all may be tooth-like structures “denticles”. It tends to occur in 62% in the anterior region of the maxilla and usually associated with the crown of an unerupted canine. It is formed by exuberant growth of the dental lamina or into a number of small enamel organs by proliferation of the enamel organ.

Complex Odontoma

It is composed of haphazardly arranged dental hard and soft tissue. It has no resemblance to a normal tooth. It tends to occur in 70% in the posterior region of the mandible. There might be a missing tooth if it arises from a normal tooth follice.

Clinical Features

They are the most common odontogenic tumors and they interfere with eruption of permanent teeth. They begin to develop as normal dentition start to develop and cease when the teeth development ends. There is no sex predilection. They occur in young age group, with the average age being second decade of life. They are usually asymptomatic and are discovered during routine radiographic examination when there is delayed eruption of permanent tooth. They occur equally in maxilla and mandible.

Radiographic Features

The borders are well-defined, often with a cortex surrounding a soft tissue capsule. The internal structure is largely radiopaque. They often interfere with normal eruption of teeth. They can be associated with impacted, malposition, malformation, and displacement of adjacent teeth.

Differential Diagnosis

Compound odontomas can be detected easily due to their tooth-like appearance. Complex odontomas can be differentiated from cemento-ossifying fibromas due to their propensity to be associated with crown of unerupted molar and they are more radiopaque than cement-ossifying fibromas. They can also develop at much younger age than cemento-ossifying fibromas. A dense bony island can be included in the differential. However, the presence of a soft tissue capsule is very useful in differentiation. Periapical cemental dysplasia may resemble complex odontomas but usually they are multiple, surrounded by sclerotic borders and centered around apices of teeth, whereas odontomas are commonly found occlusal or overlapping the involved teeth.

Treatment

Compound and complex odontomas are easily removed by simple excision. They don’t recur and are not invasive.

Case Reports

HISTORY: A 28-year-old female was referred for a Cone Beam CT scan for evaluation of left mandibular canine/premolar area for pathology.


FINDINGS: There is a well-defined mixed density lesion between roots of teeth #20-21. The lesion is surrounds by radiolucent band and radiopaque cortex giving it a target appearance. The heterogeneous density within the lesion has tooth like appearance and density. It measures approximately 12 mm at its greatest dimension. There is displacement of roots of #20 and #21. There are no signs of root resorption. The lesion is in close proximity to the mental foramen. The mandibular canal is located inferior and buccal to the lesion.


IMPRESSION: The radiographic signs suggest a benign process and are consistent with compound odontoma.