Odontoma (Doctor Faris Alabeedi MSc, MMedSc, PgDip, BDS.)

1. Odontoma Compound odontoma , complex odontomas , odontogenic hamartoma .

2. This group of tumors is composed of proliferating odontogenic epithelium in a cellular ectomesenchyme resembling the dental papilla. One of the Tumors of Odontogenic Epithelium

3. 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

4. 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 .

5. Clinical Features They are usually asymptomatic and are discovered during routine radiographic examination when there is delayed eruption of permanent tooth. Location: Somewhat more common in the maxilla. The compound type is more often in the anterior maxilla while the complex type occurs more often in the posterior regions of either jaw.

6. Two types of odontomas are recognized Complex Compound

7. 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.

8. 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 .

9. Radiographic Features Early lesions are radiolucent with smooth, well-defined contours . Later a well-defined radiopaque appearance develops . Most odontomas are small and do not exceed the size of a normal tooth in the region. However, large ones do occur and these may cause expansion of the jaw . Most odontomas are asymptomatic and as a result are discovered upon routine radiographic examination .

10. Radiographic Features * Odontomas may block the eruption of a permanent tooth and in these cases are often discovered when “searching for” the “missing” tooth radiographically . *They can be associated with impacted, malposition , malformation, and displacement of adjacent teeth.

11. Complex odontoma radiographiclly Common lesions that persist through life Usually detected in adolescence most commonly in mandibular molars not painful, or swelling radiographically "sunburst radiopacities , thin uniform radiolucent rim similar description as osteosarcoma , but assoc w/ tooth, clear of bony borders

12. large radioopaque lesion well encapsulated w/ radioiolucent border

13. Compound odontoma radiographiclly *Most common odontogenic tumor *Appears as a cluster of multiple abortive teeth *Often prevents normal tooth eruption * Radiographically multiple tiny toothlike structures are contained within a fine radiolucent rim *Do not recur after excision *thus discovered during adolescence Histology of compound odontomas approaches normal tooth strcture . Gross clinical examination usually is sufficient for diagnosis.

14. 3 small radioopaque lesion w/ radiolucent rim

15. 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 .

16. Differential Diagnosis 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.

17. Treatment Odontomas are treated by simple local excision and the prognosis is excellent They don’t recur and are not invasive.

18. 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. Case Reports