不可复性关节盘前移位的颞下颌关节系统生物力学研究

目的：研究构建病理状态下的颞下颌关节系统三维有限元模型并进行力学分析，探讨不可复关节盘前移位后颞下颌关节系统的应力分布情况。方法：利用CT和MRI扫描，通过Mimics和Geomagic软件平台，构建病理状态下的颞下颌关节系统三维模型，并在其基础上进行力学分析。结果：建立了包括上、下颌骨，关节窝、全牙列及关节盘的颞下颌关节系统个体化三维数字模型。力学分析显示．正常关节盘的应力集中在中带外侧部，应力分布较均匀，而当关节盘前移位时，关节盘的中带出现应力集中现象．容易引起该部位关节盘变薄或穿孔：髁突表面应力主要分布在前斜面．而当关节盘前移位时，髁突受力增大．提示该部位易发生退行性变。结论：利用cT和MRI，能够实现对病理状态下的颞下颌关节系统的三维重建．且关节盘移位侧的关节盘、髁突应力峰值均大于正常侧关节。

Biomechanics of the temporomandibular joint system with anteriorly displaced discs without reduction

PURPOSE： To study the construction of the temporomandibular joint system in pathologic condition, and mechanical analysis of the system stress distribution of temporomandibular joint with anteriorly displaced discs without reduction. METHODS： Using their own advantages of CT and MRI scans, through the Mimics and Geomagie software platform, three-dimensional model of temporomandihular joint system in pathological condition was constructed and mechanical analysis was performed. RESULTS： Individual three-dimensional digital model of temporomandihular joint system was established, which included the upper and lower jaws, glenoid fossa, the whole dentition and articular disc. Mechanical analysis showed that the stress of normal articular disc concentrated in the lateral part, and the stress distribution was more uniform, when the articular disc displaced, stress concentration occurred, which was likely to cause thinning of the articular disc or perforation; Condylar surface stress was mainly distributed in the former slope, and when the articular disc displaced, the forces the condyle increased, which was prone to degeneration. CONCLUSIONS： Based on CT, MRI scaning, pathological state of the temporomandibular joint system can be constructed. The disc and condyle stress peak value on displace side is greater than the normal side. Supported by Research Fund of Science and Technology Department of Zhejiang Province （2010C33123）.