Abstract: PURPOSE: Changes of root shape of impacted upper central incisor before and after orthodontic traction were observed with dental cone-beam CT(CBCT), the timing for traction of impacted upper central incisor was investigated. METHODS： Ten impacted maxillary central incisors were diagnosed via panoramic radiograph. CBCT images were taken preoperatively for accurate localization. Following combined treatment of dental surgery and orthodontic traction, ten impacted maxillary central incisors were guided out and aligned well. Final treatment results and the root development status were evaluated via CBCT. RESULTS: Ten impacted maxillary central incisors were tracted to normal position. CBCT images before and after treatment showed that the root of impacted incisors with completed root apex had no change in shape, while the root of impacted incisors with uncompleted root apex developed continually with obviously improved shape and length. CONCLUSIONS: Optimistic results can be achieved if the traction of impacted upper central incisor is carried out before root development completed.

Key words: Impacted maxillary central incisor, Orthodontic traction, Cone-beam CT