不同咬合方式对颞下颌关节内应力分布的影响(“研究生论坛”稿件)

研究不同咬合方式下颞下颌关节(TMJ)内各结构的应力分布情况,揭示不同生理状态下TMJ的生物力学特性。依据正常人头部CT图像,建立包含下颌骨和全牙列的TMJ3维有限元模型。关节盘与髁突、关节盘与关节窝之间的相互作用考虑为接触,施加与正中咬合、前牙咬合、右侧磨牙咬合相对应的载荷和边界条件,对比分析TMJ的应力分布规律。结果表明,前牙咬合和右侧磨牙咬合工况下TMJ内各结构的应力明显高于正中咬合工况。3种工况下关节盘各带的应力值都呈现出:中带应力>后带应力>前带应力,且腹面应力>背面应力。在各种咬合工况下关节盘中带都是高应力区;单侧磨牙咬合时对侧TMJ的应力明显高于同侧,应尽量避免长期单侧咬合。

Effects of Occlusal Loads on the Stress Distributions in Temporomandibular Joint

Abstract: The stress distributions of the temporomandibular joint(TMJ) under centric occlusion, anterior occlusion and unilateral occlusion were analyzed. A three-dimensional finite element model of the TMJ with mandible and teeth was developed according to CT images of a volunteer with asymptomatic joints. Contact elements were used to simulate the interaction between the articular discs and the mandibular condyles and between the articular discs and the articular fossas. The muscle forces and boundary conditions corresponding to the three occlusions were applied on the model. It was observed that the stresses of the TMJs in the models with anterior occlusion and unilateral occlusion were higher than those in the model with centric occlusion. In the three models, the maximum and minimum stresses of the discs occurred in the intermediate zones and the anterior bands, respectively. Moreover, the stresses on the ventral disc were higher than the dorsal disc. The high stresses of the discs were located at the intermediate zones under the three occlusions. The stress of the contralateral TMJ was much higher than the ipsilateral TMJ under the unilateral occlusion.