下颌前伸时颞下颌关节应力分布的三维有限元研究

Stress analysis of temporomandibular joint in state of mandibular protraction by means of three-dimensional finite element method

目的探讨下颌前伸运动时颞下颌关节内的应力分布情况。方法利用可视化人体图像建立包括上下牙列、下颌骨、颞下颌关节在内的三维有限元模型,在Patran中采用位移加载的方法模拟下颌前伸运动至对刃位,在Marc中计算并分析接触情况和应力分布特性。结果关节盘随髁突向前、下运动,髁突的前斜面首先与关节盘中间带中央部发生接触,随后髁突的外斜面与关节盘的中间带外侧部、关节窝的顶部与关节盘的后带发生接触。关节盘的中间带外侧部(3.10 Mpa)和髁突的前斜面(5.05 Mpa)等部位的应力值较大。结论在前伸运动时,应力集中区位于关节盘的中间带外侧部和髁突的前斜面。

Objective To investigate stress distribution in the temporomandibular joint （TMJ） during mandibular protraction. Methods On the basis of images of the Chinese Visible Human,the three-dimensional finite element model of the TMJ was established, including dental arches, mandible and so on. Displacement was introduced as the loading condition to simulate the mandibular protraction from intercuspal position to edge-to-edge dental occlusion. The contact areas and stresses of various structures in the TMJ were calculated and analyzed in Marc. Results The disc following the condyle moved downwards and forwards during protntsive movement. The anterior inclined plane of the condyle contacted with the center of the intermediate zone of the disc. Then the lateral inclined plane of condyle contacted with the lateral part of the intermediate zone of the disc while the top of the articular fossa contacted with the posterior band. The stress values of the lateral part of the intermediate zone of the disc（ 3.10 Mpa）and the anterior inclined plane of condyle （5.05 Mpa）were high. Conclusion It is suggested that the concentrated areas of stress were in the lateral part of the intermediate zone of the disc and the anterior inclined plane of condyle during protrusive movement.