The use of spiral computed tomography in the localization of impacted maxillary canines.

PURPOSE To compare spiral CT with conventional radiography in planning the orthodontic treatment of impacted permanent maxillary canines. METHODS Nineteen patients with 29 malpositioned permanent maxillary canines (15 palatal and 12 buccal impactions, one ectopic and one transposition) were examined with conventional panoramic and lateral cephalometric radiography and with spiral CT (at 1 mm slice thickness, and 1:1 or 2:1 pitch) using multiplanar (MPR) and 3D reconstruction. RESULTS Conventional radiography failed to depict root resorption especially on the buccal surfaces of the incisor teeth. CT located impacted teeth better. Contact between impacted maxillary canines and incisor roots was demonstrated in 26 cases and root resorption in eight. MPR proved to be superior for the orientation of impacted teeth, and, in two cases, confirmed the presence of minimal root lesions for which axial images had proved inconclusive. The 3D reconstructions were useful in targeting the MPR. CONCLUSIONS CT facilitates ...