Abstract: Objective To analyze the root resorption and possible related factors of adjacent incisors after orthodontic traction of maxillary impacted canines. Methods Forty three patients, with sixty impacted maxillary canines in total, aged from 10 to 23, were selected. Cone-beam CT was taken before and after orthodontic traction treatment of maxillary impacted canines. The degree of root resorption of impacted canines adjacent to incisors was analyzed, and possible related factors were explored. Results After orthodontic traction treatment of maxillary impacted canines, the incidence of mild, moderate and severe root resorption of maxillary central incisors was 71.7%, 15.0% and 13.3% respectively, and the incidence of maxillary lateral incisors was 48.3%, 36.7% and 15.0% respectively. The severity of root resorption was different between maxillary central incisors and lateral incisors (P＜0.05). After orthodontic traction treatment of impacted canines which were located on the palatal side and in the jaw, low and close to the midline of the face, the root resorption of lateral incisors was more severe (P＜0.05). After traction treatment of low impacted canines, the root resorption of central incisors was more severe (P＜0.05).The root resorption of central incisors was more severe when the traction time was longer (P＜0.05). For incisors with root resorption before treatment, the degree of root resorption after traction treatment of impacted canines was more severe (P＜0.05). Conclusion After orthodontic traction treatment of impacted canines, the root resorption of maxillary lateral incisors is more severe. After orthodontic traction treatment of maxillary impacted canines, the root resorption of adjacent incisors is related to the position of impacted canines, the duration of traction treatment and whether root resorption has occurred before treatment.

Key words: impacted canine, orthodontic traction treatment, incisor, root resorption, cone-beam CT