模拟功能咬合时人颞下颌关节内的应力分布和位移特征

THE CHARACTERISTICS OF STRESS AND DISPLACEMENT IN HUMAN TEMPOROMANDIBULAR JOINT DURING CENTRIC OCCLUSION

为了认识正中咬合时颞下颌关节(TMJ)内的应力分布和位移特征 ,作者采用基于小波金字塔分解的方法对人颅颌面CT、MRI医学图像进行融合 ,以测量和分析颅颌面部各咀嚼肌的三维肌力向量 ,再借助实验获得的人TMJ各结构的材料性能参数和在活体基础上建立的模拟了关节内接触关系的TMJ三维非线性有限元模型 ,计算并分析正中咬合时TMJ内各结构的应力和位移。结果显示 ,正中咬合时关节盘、髁突和关节窝表面应力分布的范围和力值大小差异较大 ,以髁突受力最大 ,关节窝次之 ,而关节盘相对较小。正中咬合时关节盘、髁突和关节窝向上、后及内侧移动 ,以髁突位移最大 ,关节盘次之 ,关节窝最小。研究表明 ,在临床实践中 ,系统、合理地计算和分析正中咬合时TMJ内的应力分布和位移特征是切实可行的 。

In order to study the stress distribution and displacement characternstic of the temporomandibular joint (TMJ) during centric occlusion, using the three dimensional nonlinear finite element model of normal human TMJ developed from in vivo with simulation of the contact relationship within TMJ, the stress and the maximum displacement of various structures in the TMJ were calculated and analyzed during centric occlusion. Furthermore, we separately accounted the mechanical properties of various structures in human TMJ and three dimensional muscle force vectors of their masticatory muscles measured and analyzed by use of the fusion of cranio jaw facial CT and MR image with the multiresolution method based on wavelet pyramid. The results showed that there were significant differences in the region and value of stress distribution on the surface of the disc, condyle and articular fossa during centric occlusion, in which the biggest stress was distributed in the condyle, the second in the articular fossa, and the smallest in the disc. During centric occlusion, the disc, condyle and articular fossa moved upperly, posteriorly and medially with the biggest displacement on the condyle, the secondary one on the disc and the smallest one on the fossa. It suggested that it is clinically feasible to systematically and rationally calculate and analyze the stress distribution and displacement character, and the results were satisfying