颞下颌关节内软组织的模拟方式

对比分析关节盘周围软组织的不同模拟方式对颞下颌关节（TMJ）内各结构的位移和应力分布的影响。选择一位无TMJ症状的志愿者,基于其头部CT扫描建立下颌骨和TMJ的3维有限元模型,关节盘周围软组织分4种方式进行模拟,关节盘及其周围软组织和关节软骨层间考虑接触,施加正中咬合的载荷。结果表明,将关节盘周围软组织建立为实体模型,使得关节盘偏离正常位置,且TMJ的功能区（髁突前斜面-关节盘中带-关节结节后斜面）都是低应力区。将双板区建立为实体模型,关节盘接近正常的位置,但仍没体现出TMJ的功能区应力较高的现象。用非线性缆索元来模拟关节盘前、后附着,关节盘处于正常位置,且髁突和颞骨的最大应力都出现在前部区域,关节盘的最大应力出现在中带。当研究重点是TMJ时,应该采用缆索元来模拟双板区和关节盘前附着,同时考虑关节盘与关节软骨层之间的接触。

Numerical Simulations of the Soft Tissues in Temporomandibular Joint

The influences of different simulations of soft tissues around disk on the movement and stress distribution of the temporomandibular joint (TMJ) were analyzed. A three-dimensional finite element model of the mandible, temporal bone and articular disk was developed according to CT of a volunteer with asymptomatic joints. The soft tissues around disk were simulated as four types. Contact elements were used to simulate the interaction of the disk with the soft tissues and the articular surfaces. The muscle forces corresponding to centric occlusion were applied to the four models. The results showed that the disks rotated round the condyles in the model with the soft tissues around disk constructed as solid models. Moreover the stresses of the intermediate zones of disk and the anterior regions of condyle and temporal bone were so low. The disks were close to the normal position in the models with the bilaminar zones constructed as solid models, whereas the stress distributions in the TMJs were abnormal. The disks in the model with the attachments of the disks simulated as nonlinear cable elements were in the normal position. Moreover the maximum stress of the disks occurred in the intermediate zones, and the maximum stress of the condyles and temporal bones occurred in the anterior regions. The attachments of disk should be modeled as cable elements, and the interaction of the disk and the articular surfaces should be simulated as contact elements.