异常牙根形态对正畸治疗前后前牙根吸收的影响

目的 调查异常牙根形态在正畸治疗前后对牙根吸收的影响。方法 随机选择经直丝弓矫治技术完成的病例153例，分析患者治疗前后的全口曲面断层片，将前牙按根形态分为正常组、短根组、钝根组、弯根尖组及滴管状根组5组，以Levander和Malmgren的牙根吸收分级法记录每个前牙牙根根吸收程度，将牙根根吸收程度及其改变的频数进行统计分析。结果 前牙中异常根形态的发生率为16.92%，以弯根尖与钝根最为常见；根形态异常组与正常组的根吸收均值间在正畸治疗前有显著性差异（P<0.05），正畸治疗后亦有显著性差异（P<0.01），其中短根组根吸收值最高，其次为滴管状根组；根形态异常组在正畸治疗前后的根吸收发生率均较正常组高，差异有显著性（P<0.01）。结论 异常牙根形态能显著增加牙根吸收的发生率和严重程度。

Effects of abnormal anterior root shapes on root resorption in orthodontic patients

Objective To investigate effects of abnormal anterior root shapes on root resorption in orthodontic patients.Methods 153 cases treated with straight wire appliance were randomly selected.Pretreatment and posttreatment panoramic radiographs of those patients were examined to assess changes in root length and apical contour according to criteria modified from Levander and Malmgren.Changes of the prevalence and severity of root resorption were analyzed.Results The prevalence of abnormal root shapes was 16.92%....