关键词: CBCT, 牙根吸收, 根管治疗, 正畸治疗

Abstract: Objective To investigate whether rootfilled teeth would suffer external apical root resorption after orthodontic treatment compared with vital pulp teeth by CBCT (cone beam computed tomography). Methods 16 adult patients with slightlymoderately crowded teeth were selected. At least one of each patients maxillary anterior teeth had been treated with root canal treatment. 0.5588 mm MBT bracket (3M Unitek) was applied to the nonextraction treatment. The CBCT images were collected, and the lengths of the treated tooth and the contralateral tooth were measured using axialguided navigation before and after treatment. The statistical difference was compared using the paired ttest. Results A total of 18 maxillary anterior teeth, including 6 central incisors, 8 lateral incisors, and 4 canines, had received root canal treatment among 16 patients. The average treatment duration was (18.3 ± 2.6) months. Before treatment, the length of posterior rootfilled teeth was (22.68±2.14) mm, and the length was (21.98±2.05) mm after treatment. The length of the contralateral vital pulp tooth was (22.61±2.01) mm before treatment, and after treatment, the length was (22.01±2.37) mm. There was no statistical difference in root length between filled and vital roots in either preorthodontic or postorthodontic treatment. Similar results were also observed on the stratified analysis by the type of teeth. Conclusion CBCT is a good way to observe apical root resorption. In nonextraction cases with lightlymoderately crowded teeth, orthodontic treatment will not increase the risk of apical root resorption of the rootfilled upper anterior teeth.

Key words: CBCT, root resorption, root canal treatment, orthodontic treatment