阻生尖牙牵引治疗前后上颌切牙牙根外吸收的锥形束CT分析

Cone-beam CT analysis of external root resorption of maxillary incisors before and after traction of impacted canines

目的通过锥形束CT测量探讨阻生尖牙牵引治疗前后上颌切牙牙根外吸收的变化。方法选取2011年7月至2019年1月于南京医科大学附属口腔医院正畸科就诊的上颌尖牙阻生致切牙牙根外吸收的患者24例,年龄(12.3±1.6)岁(10~14岁),其中男性11例,女性14例。将治疗前牙根发生外吸收的上颌切牙纳入吸收组(中切牙21颗,侧切牙22颗),以牙根未发生外吸收的同名上颌切牙为对照组(中切牙26颗,侧切牙21颗)。对正畸治疗全部完成满1年的患者进行随访并拍摄锥形束CT,随访到患者15例,其中吸收组中切牙10颗、侧切牙12颗,对照组中切牙16颗、侧切牙12颗。测量分析上颌切牙在牵引前(治疗前)、牵引后(阻生尖牙牵引到位时)及随访时(正畸治疗全部完成后1年)的牙根长度及牙体体积,同时分析尖牙牵引期间(牵引前-牵引后)及随访期间(牵引后-随访时)牙根长度及牙体体积的变化量。结果牵引后吸收组和对照组中切牙和侧切牙牙根长度及牙体体积均显著小于同组牵引前(P<0.05)。除吸收组侧切牙牙体体积外,随访时吸收组和对照组切牙牙根长度及牙体体积均显著小于同组牵引后(P<0.05)。尖牙牵引期间吸收组侧切牙体积变化量[(17±6)mm^(3)]显著大于对照组侧切牙[(12±5)mm^(3)](t=2.51,P<0.05)。随访期间吸收组中切牙牙根长度变化量[(0.5±0.4)mm]显著大于对照组中切牙[(0.2±0.1)mm](t=2.35,P<0.05)。结论对于上颌尖牙阻生致牙根外吸收的上颌切牙,阻生尖牙牵引到位后牙根外吸收并不能即刻停止。上颌侧切牙的牙根外吸收主要发生于阻生尖牙牵引期间,上颌中切牙的牙根外吸收存在于整个正畸过程及后期随访中。

Objective To analyze the external root resorption of incisors caused by maxillary canine impaction,and to explore the changes of incisor external root resorption after orthodontic treatment.Methods Twenty-four patients with impacted maxillary canines leading to external root resorption of incisors treated in Department of Orthodontics,Affiliated Hospital of Stomatology,Nanjing Medical University from July 2011 to January 2019 were selected.The age ranged from 10 to 14 years[(12.3±1.6)years],including 11 males and 14 females.The maxillary incisors with external root resorption before treatment were included in the resorption group(21 central incisors and 22 lateral incisors),and the maxillary incisors without external root resorption were used as the control group(26 central incisors and 21 lateral incisors).Cone-beam CT was taken before treatment,immediately after treatment and one year after treatment.At the one year follow-up 15 patients were collected(10 central incisors and 12 lateral incisors in the resorption group,while 16 central incisors and 12 lateral incisors in the control group).The root length and tooth volume of maxillary incisors were measured and analyzed before canine traction,after canine traction finished and at the one year follow-up.Results After the treatment of maxillary impacted canines,the root length and volume of the central and lateral incisors in both resorption group and control group were significantly less than that before treatment(P<0.05).At the one year follow-up,the root length and volume of the incisors(central incisors in the resorption group and the central and lateral incisors in control group)were significantly less than those immediately after impacted canine traction(P<0.05).During the canine traction,the difference of the volume change in lateral incisors between the resorption group[(17±6)mm^(3)]and the control group[(12±5)mm^(3)]was statistically significant(t=2.51,P<0.05).During the one year follow-up period,the difference between the changes of the root length in maxillary central incisors in the resorption group[(0.5±0.4)mm]and in the control group[(0.2±0.1)mm]was statistically significant(t=2.35,P<0.05).Conclusions For maxillary incisors with external root resorption caused by impacted maxillary canines,the external root resorption could not stop immediately after the treatment of impacted canines.The root resorption in maxillary lateral incisors mainly occured during the traction process,while the root resorption in maxillary central incisors existed during the orthodontic treatment and in the follow-up period.