Abstract:  Objective    To investigate the incidence of double root canals in mandibular lateral incisors，the opening position of the lingual root canals and the bifurcation angle between the two root canals by cone beam CT （CBCT），and to provide theoretical basis for clinical treatment of double root canals in mandibular lateral incisors. Methods    From October 2019 to May 2020，CBCT data of 300 patients who met the inclusion criteria were randomly selected from the CBCT imaging data of dental implant，orthodontics，pulp diseases and other reasons in the Department of Stomatology of the General Hospital of the Western Theater Command of China. The images of 586 mandibular lateral incisors that met the inclusion criteria were analyzed and double root canal teeth were screened out. They were divided into groups by age, and the location of the opening of the lingual root canal and the angle of the bifurcation of the root canal were recorded and analyzed. Results    Totally 95 of the 586 mandibular incisors were with double root canals，and the incidence of double root canals was 16.2%. In low-age （≤ 30），middle-age （> 30～60） and high-age （> 60），the distance between the lingual root canal opening and the cut end was（12.48 ± 1.43）mm，（11.18 ± 1.21）mm and（9.81 ± 0.86）mm，respectively，and the difference was statistically significant（P < 0.05）. There was no significant difference in the bifurcation angle of root canal among different age groups（P > 0.05）.The distance from the lingual root canal opening of the mandibular incisor to the cut end and the bifurcation angle of the root canal were symmetrical between the left and right sides (r values were 0.626 and 0.603, respectively, both P < 0.001). Conclusion    The incidence of double root canals in mandibular lateral incisors is relatively high, and with the increase of age, the distance from the tongue root canal opening to the incisal end gradually decreases; at the same time, the incidence of double root canals on both sides, the distance from the tongue root canal opening to the incisal end, and the angle of tube bifurcation are highly symmetrical.

Key words: double root canal, mandibular lateral incisors, lingual root canals, cone beam CT, different age

摘要： 目的    通过锥形束CT（cone beam CT，CBCT）对下颌侧切牙双根管发生率及双根管牙的舌根管开口位置和双根管间分叉角度进行研究，为临床中对双根管下颌侧切牙的治疗提供理论依据。方法    于2019年10月至2020年5月在西部战区总医院口腔科因种植、正畸、牙髓病等原因拍摄的CBCT影像学资料中随机抽取300例符合纳入标准的患者CBCT资料，对其中符合纳入标准的586颗下颌侧切牙的影像进行分析，筛选出其中的双根管牙，将它们按患者年龄分组，记录舌根管开口处的位置及根管分叉角度，并进行分析。结果    纳入研究的586颗下颌侧切牙中有95颗为双根管，双根管发生率为16.2%；在低年龄组（≤ 30岁）、中年龄组（> 30 ~ 60岁）及高年龄组（> 60岁），双根管下颌侧切牙的舌根管开口处距切端距离分别为（12.48 ± 1.43）、（11.18 ± 1.21）、（9.81 ± 0.86）mm，组间差异有统计学意义（P < 0.05）；而根管分叉角度在各年龄段的差异无统计学意义（P > 0.05）。下颌侧切牙舌根管开口处至切端距离和根管分叉角度在左右侧之间均具有对称性（r值分别为0.626和0.603，均P < 0.001）。结论    下颌侧切牙双根管发生率较高，并且随着年龄的增加，舌根管开口处至切端的距离在逐渐减小；同时两侧的双根管发生率、舌根管开口处至切端距离以及根管分叉角度均有较高的对称性。

关键词: 双根管, 下颌侧切牙, 舌根管, 锥形束CT, 不同年龄