舌侧矫治系统中控制前牙转矩牵引力方向的HITS实验研究

Analysis of retraction direction about controlling the anterior teeth torque in lingual orthodontic system based on HITS

目的:通过HITS系统中关闭间隙阶段的Typodont实验,对在舌侧矫治中良好控制前牙转矩方向进行优化组合。方法:选取16副标准上颌安氏Ⅱ~1拔除第一前磨牙的Typodont模型,分别在后牙区舌侧区和前牙区唇侧根尖区植入微种植体,通过改变舌侧微种植体位置和牵引钩长度来调节回收力的方向,及HITS模拟牙齿移动效果,并借助Micro CT扫描加力前后模型并进行Mimics 17.0软件三维重建,用SPSS22.0软件进行析因方差分析。结果:舌侧矫治关闭拔牙间隙过程中,在加载回收力的同时配合唇侧压低力可较好的控制前牙转矩。当牵引钩高度为4mm,舌侧微种植体距牙槽嵴顶6 mm时,前牙切缘与根尖的位移差值较小;当牵引钩高度为8 mm,舌侧微种植体距牙槽嵴顶10 mm时,位移差值较小。结论:"微种植体支抗—双槽沟舌侧托槽"矫治系统下,拔牙间隙关闭阶段牵引钩4 mm/微种植体6 mm及牵引钩8 mm/微种植体10 mm时可较好的控制前牙转矩。

Objective：To optimize the direction of the anterior teeth torque during the closing space by Typodont experiment based on HITS.Methods：Sixteen Class Ⅱ-1 maxillary Typodonts without first premolar were made.Micro-implants were implanted in the lingual region of the posterior teeth area and labial region of the anterior teeth area.The direction of the retract force was adjusted by changing the position of the lingual micro-implant and the length of the hook.The tooth movement was simulated by HITS then the models were scaned before and after loading the force.With that,the three-dimensional images were reconstructed by Mimics 17.0 software and Factorial variance analysis with SPSS 22.0 software.Results：It can control the anterior teeth torque better when loading labial depressing force at the same time.During the closing space,the difference of the anterior teeth movement displacement between the incisal edge and the root apex was smaller in the group with 4 mm hook length and 6 mm distance from the alveolar crest of the lingual micro-implant place.The difference was also smaller in the group with 8 mm hook length and 10 mm distance from the alveolar crest of the lingual micro-implant place.Conclusion：During the closing space,it can provide an effective anterior torque with 4 mm hook length/6 mm micro-implant implant place or 8 mm hook length/10 mm micro-implant implant place by the Micro-Implant Anchorage-Lingual Orthodontic System.