[Dental ankylosis diagnosed by CT with tridimensional reconstructions].

The etiology of unerupted teeth often is difficult to establish. It may relate to abnormal orientation of the tooth bud, an anatomical obstacle, pathology of the dental sac or ankylosis. The ankylosis process and diagnosis are analyzed in this clinical series. Ankylosis and its underlying physiological process are abundantly described in the literature. Nonetheless, diagnosis remains difficult to achieve. Clinical evaluation and complementary radiographic techniques such as dental radiographs and orthopantomogram are considered by some authors as poorly reliable. These clinical examinations based on a series of subjective criteria cannot be performed on unerupted teeth. In a series of patients with unerupted or retained teeth of undetermined etiology or with traction failure, 15 were diagnosed with ankylosis. The diagnosis of ankylosis could not be achieved based on clinical or radiographic evaluation and required CT imaging. Source images along with tridimensional reconstructed images were evaluated using the MVS software (Hospices Civils of Lyon). The radicular volume involved by ankylosis could be measured and its exact location on the tooth could be demonstrated. This imaging technique with tridimensional reconstruction provided positive diagnosis of ankylosis.