基于计算机辅助设计的个性化舌侧矫治的前牙内收系统的临床研究

目的 评价计算机辅助设计的个性化舌侧前牙内收系统对前牙整体内收过程中转矩控制的效果.方法 选取20例拔除上颌第一双尖牙并且采用个性化舌侧系统进行矫治的正畸病例,采用舌侧牵引延长臂(lever-arm)和腭侧微种植钉整体内收上颌6颗前牙.基于患者的CBCT数据,采用Mimics 10.0和Claytool软件确定舌侧牵引延长臂的长度和微种植钉植入部位,使内收力作用线通过前牙阻抗中心并与(牙合)平面平行.对比内收前后软组织、骨骼和牙齿的相关头影测量值变化.结果 治疗前和内收后的头影测量结果显示,上中切牙切缘至PTV的距离(PTV-U1)和上唇至审美平面距离(LS-E)显著减小(P＜0.001),上中切牙切缘至腭平面垂线距离(PP-U1)无显著性变化(P＞0.05).上颌前牙发生了大部分的整体内收和少量的控制性倾斜移动,软组织侧貌明显改善,同时磨牙未出现明显移位.结论 计算机辅助设计和定位的个性化舌侧内收系统,显著提高了舌侧矫治中前牙转矩的控制精度.

A clinical study of retraction system of maxillar anterior teeth with computer-aid designed for individual lingual orthodontics

Objective To evaluate the effects of anterior torque controlling with individual lingual en masse retraction in the maxillary anterior teeth using computer-aided designed lever-arm and miniscrew system. Methods 20 non-growing cases with treatment protocol of extraction was selected and treated with individual lingual system, employing the lever-arm and miniscrew as en masse retraction system. Based on CBCT data, Mimics 10. 0 and Claytool software was used to determine the length of the lever-arm and the position of the miniscrew so as to make sure the line of action of retraction force pass through the center of resistance of 6 maxillary anterior teeth and parallel to occlusion plane. The cephalograms were analyzed for differences in skeletal, dental and soft tissue variables between pretreatment and postretraction. Results Distances from tip of upper central incisor to PTV （PTV-U1） and upper lip to E line （LS-E） was significantly decreased （P〈0. 001）, and no significant difference was noted for the distance from tip of upper central incisor to Palatal Plane （P~0. 05）. Significant retraction of maxillary anterior teeth was achieved in all patients and improved profile was obtained. Bodily movement and slightly controlled tipping occurred during the retraction and maxillary molars did not show any statistically significant movement. Conclusions The computer-aided design and location of the lingual retraction system （lever-arm and miniscrew） produced excellent and efficient retraction with great accuracy in control of anterior torque.