无托槽隐形矫治器和直丝弓矫治器对切牙牙根吸收的影响

目的:评估使用无托槽隐形矫治器和直丝弓矫治器的患者切牙牙根吸收情况.方法:分别选取28例使用无托槽隐形矫治器(实验组)和直丝弓矫治器(对照组)的患者,分析患者术前、术中6个月及术后的锥形束CT(CBCT)影像.通过测量各时间段的牙根长度,比较2组患者牙根吸收有无差异.对于牙根长度未见变化的患牙,通过CBCT检测其有无单纯唇腭侧和近远中骨质吸收.采用SPSS16.0软件包对数据进行统计学分析.结果:术后6个月,实验组患者47.3％的牙出现牙根吸收,显著少于对照组的68.8％ (P＜0.05).2组患者上颌中切牙牙根吸收的发生率均高于其他牙(实验组为55％,对照组为75％).矫治完成后,对照组牙根吸收的发生率上升到85.3％,而实验组上升到68.3％(P＜0.05).部分牙根长度未见减少的牙也存在局部根吸收,骨吸收最常发生在牙根的腭侧面(实验组为18％,对照组为14％).结论:与传统直丝弓矫治器相比,使用无托槽隐形矫治器的患者切牙牙根吸收程度较小.

A retrospective study on incisor root resorption in patients treated with bracketless invisible appliance and straight wire appliance

PURPOSE:To assess root resorptions in patients treated with bracketless invisible appliance and straight wire appliance using cone-beam CT (CBCT).METHODS:Twenty-eight patients treated with bracketless invisible appliance (as experimental group) or straight wire appliance (as control group) were randomly selected.CBCT images were analyzed at 3 time points (pre-operation,6 month after operation,post-operation).Root resorption was calculated using root length at 3 time points.The difference between the 2 groups was analyzed with SPSS16.0 software package.To those teeth with no root length reduction,the bone defect was evaluated using CBCT.RESULTS:After 6-month of treatment,47.3％ teeth from the experimental group had root resorption,while 68.3％ in the control group.There was significant difference between the 2 groups (P＜0.05).Root absorption of maxillary central incisors from the 2 groups was more severe than other teeth (55％ in the experimental group,and 75％ in the control group).After orthodontic treatment,the incidence of root resorption in the control groups increased to be 85.3％ and 68.3％ in the experimental group (P＜0.05).To those teeth with no root resorption,bone defect was more common in the palatal side (18％ in the experimental group,14％ in the control group).CONCLUSIONS:Compared with straight wire appliance,patients using bracketless invisible appliance suffer from less root resorption.