减阻牵张成骨术快速移动尖牙的三维有限元分析

Three-dimensional finite element analysis of rapid movement canine tooth through reducing resistance and distracting procedures

目的建立减阻牵张成骨术快速移动尖牙的三维有限元模型，探讨尖牙远中移动时及牙周组织的应力分布情况，为其临床广泛应用提供理论依据。方法通过64排螺旋CT扫描，获得颞下颌关节（TMJ）、下颌骨、下颌牙列截面影像的DICOM数据。采刖Mimics软件、Geomagic Studio8．0软件、Unigraphics NX软件、Ansys11．0软件相结合的方法，建立常规状态下移动尖牙（模型1）、牙周膜牵张成骨术快速移动尖牙（模型2）、牙槽骨减阻牵张成骨快速移动尖牙（模型3）的二维有限元模型，对3种模型进行力的加载，并观察尖牙、牙周膜、牙槽骨应力分布。结果3种模型的最大位移均发生在尖牙牙冠的上1／3，最大位移量模型3〉模型2〉模型1，并且位移从尖牙牙冠到根尖逐渐减少；模型1最大等效应力主要集中在尖牙远中牙槽嵴中间处，而模型2、3最大等效应力集中区转移到了尖牙远中牙槽嵴偏向舌侧处。结论在牵引尖牙远中移动过程中，去除其部分骨阻力，能有效加速牙移动速度，同时，尖牙有远中倾斜移动趋势；在牵引力作用下尖牙向远中移动的同时有再向旋转的趋势，我们礼临床工作中采取相应措施避免尖牙舌向旋转。

Objective To establish a three dimensional finite element model of rapid canine tooth movement by reducing resistance and distracting procedures, and to discuss canine distal move ment and force distribution of periodontium, and to provide theory basis for its clinical application. Methods Through 64-slice spiral scanning, temporomandibular joint （TMJ）, the mandible, lower jaw denture section phantom DICOM data were obtained. Mimics software, Geomagic Studio 8.0 soft-ware, Unigraphics NX software, and Ansysl 1.0 software were mixed, and the three-dimensional fi-nite element model were established under the conventional condition to move the canine （model 1）, rapid canine movement through distracting osteggenesis of the periodontal ligament （model 2）, rapid canine movement tooth movement through reducing resistance and distracting method （model 3）, the strength were carried on three kind of models and the canine, the pericementum, the tooth socket bone stress distribution were observed. Results The biggest displacements on those three models occured in canine crown on 1/3, biggest displacement quantity： model 3 〉rnodel 2 〉model 1, and the canine crown displacement reduced gradually from crown to the root point; in the model 1 most greatly equiv-alent stress mainly concentrated in the middle of distal alveolar crest, but in the models 2 and 3 most greatly equivalent stress centralism area shifted liguodistal alveolar crest. Conclusions In the process of canine distal movement, reducing bone resistance, can accelerate the tooth moving speed effectively and simuhaneously, the canine has distal motion tendency. While under the action of force, the canine tends to move ligually with the canine distal movement, and thus appropriate measures should be taken to prevent canine lingual rotation in clinical work.