Development of an evaluating system for stomatognathic function based on biomechanical analysis

本研究项目的目的是开发一种诊断系统，利用每个患者的三维有限元(3D FE)模型来评估颞颌关节的生物力学状况。利用下颌骨、下牙弓的形态测量学数据建立三维有限元模型。根据不同咬合时的肌肉形态、肌肉体积和肌电活动估计各肌肉的张力向量，并同时记录各咬合接触区的咬合力向量。根据咬合力的大小和方向估计咬合力向量。前者使用压敏胶片记录，后者使用新开发的装置测量，该装置能够使用激光位移计测量牙模中每个咬合接触区域的坐标和法线方向。结果表明，该装置测量牙合接触区的法向是可靠的。还开发了一种新的设备，能够从磁共振图像中自动检测下颌骨和咀嚼肌肉的表面。骨骼表面检测的过程包括利用活动轮廓模型从序列图像中检测轮廓和利用活动表面模型检测表面。在这个项目中，成功地从磁共振图像中检测到了髁状突皮质骨的表面。在本研究项目中，构建诊断系统所需的所有方法学要素都已充分准备好。

The aim of this research project was to develop an diagnostic system which evaluate the biomechanical condition of the temporomandibular joints using the three-dimensional finite element (3-D FE) model of each patient. Morphometric data of the mandibular bone, the lower dental arch were used to construct the 3-D FE model. Tensile force vectors of each muscles, which were estimated from the muscle form, muscle volulme and the electromyographic (EMG) activities during various types of tooth clenching, and bite force vectors on each occlusal contact area, which were simultaneously recorded with EMG,were input to the model. The bite force vectors were estimated from the magnitudes and the directions of the bite force. The former were recorded using pressure sensitive film, and the latter were measured using the newly developed device, which enables to measure a coordinate and a normal direction of each oculusal contact area in the dental cast using a laser displacement meter. This device showed to be reliable in measuring the normal direction of the occlusal contact area. The new device which enables to automatically detect the surface of the mandibular bone and the masticatory muscles from magnetic resonance (MR) images was also developed. The process of detecting the bone surface consisted of detecting the contour from serial images by active contour model and detecting the surface by active surface model. In this project, the surface of the cortical bone of the condyle was successfully detected from MR images. In this research project, all the methodological elements which were required to construct the diagnostic system were fully prepared.