上颌第一磨牙矫治过程的三维有限元分析

通过三维激光扫描,采用逆向工程技术（RE）,应用CATIA软件先后建立上颌第一磨牙、牙周膜、牙槽骨、颊面管、舌面管的三维模型,在不同加力的情况下通过Patran等有限元分析软件进行计算分析,计算出矫治力作用下上颌第一磨牙的位移、应力及其牙周组织的应力分布;观察牙齿移动、倾斜以及旋转的情况,预测了上颌第一磨牙可能发生牙槽骨丧失和牙根吸收的位置;发现了磨牙受到舌侧水平正畸力时,牙体和牙周膜所受到的压力小于颊侧加载所受的压力。结论是舌侧矫治较颊侧矫治更有利于牙齿以及牙周组织的康复,不容易引起牙根吸收。本项研究初步找出正畸治疗中上颌第一磨牙的最佳加载方案,为临床治疗提供依据。

Three-Dimensional Finite Element Analysis of the Maxillary First Molar Orthodontics

Establish the three-dimensional finite element models of the alveolar bone , the tooth the periodontal ligament （PDL） , the buccal tube and the lingual tube by the 3-dimensional laser scanning and reverse engineering. Computerize and analyze by three dimensional finite element analysis with the software of Patran. Analyze the strain and stress distributions in the periodontal ligament and the alveolus. Computerize and observe the movements （the displacement, the incline and the circumrotation） of the maxillary first molar and forecast the locations of resorption in the tooth and the alveolus when the maxillary first molar is under different orthodontic force. When the aclinic forces are applied at the lingual crown surface, the compressive stress in the tooth and the periodontal ligament is smaller than the tooth which forces are applied at the buccal crown surface . So it is more healthful for the periodontal ligament in lingual technique than in labial technique and there is less resorption of the root of the maxillary first molar in lingual technique than in labial technique. This study finds a better loading case for the maxillary first molar to supply a warrant in clinical treatment.