A dilated odontoma in the second molar region of the mandible

A case of dilated odontoma in the second molar region of the mandible was reported. The patient was a 14-year-old female. Panoramic X-ray and CT examination revealed an oval ring-shaped radiopaque lesion accompanying a radiolucent area in the center at the left second molar region of the mandible. The left second molar and all third molars were not found. The lesion was diagnosed as odontoma and extirpated under general anesthesia. The lesion was a spherical mass of 12x9mm. Histologically, the mass was composed of dentin arranged in an oval ring shape with dentinal tubules. Inside the dentin, immature enamel was present. The central area of the mass was filled with fibrous tissue with a small nest of bone and cementum. Bone tissue was also observed in contact with the immature enamel layer. These morphological and histological features are compatible with those of a dilated odontoma.