Savoldelli Charles, Bouchard Pierre-Olivier, Loudad Raounak, Baque Patrick, Tillier Yannick
Department of Oral and Maxillo-facial Surgery, Head and Neck Institute, 31 Avenue de Valombrose, Nice, France.
Surg Radiol Anat. 2012 Jul;34(5):405-13. doi: 10.1007/s00276-011-0917-4. Epub 2011 Dec 10.
This study aims at analysing the stresses distribution in the temporomandibular joint (TMJ) using a complete high-resolution finite element model (FE Model). This model is used here to analyse the stresses distribution in the discs during a closing jaw cycle. In the end, this model enables the prediction of the stress evolution in the TMJ disc submitted to various loadings induced by mandibular trauma, surgery or parafunction.
The geometric data for the model were obtained from MRI and CT scans images of a healthy male patient. Surface and volume meshes were successively obtained using a 3D image segmentation software (AMIRA(®)). Bone components of skull and mandible, both of joint discs, temporomandibular capsules and ligaments and dental arches were meshed as separate bodies. The volume meshes were transferred to the FE analysis software (FORGE(®)). Material properties were assigned for each region. Boundary conditions for closing jaw simulations were represented by different load directions of jaws muscles. The von Mises stresses distribution in both joint discs during closing conditions was analyzed.
The pattern of von Mises stresses in the TMJ discs is non-symmetric and changed continuously during jaw movement. Maximal stress is reached on the surface disc in areas in contact with others bodies.
The three-dimension finite element model of masticatory system will make it possible to simulate different conditions that appear to be important in the cascade of events leading to joint damage.
本研究旨在使用完整的高分辨率有限元模型（FE模型）分析颞下颌关节（TMJ）中的应力分布。在此使用该模型来分析闭口循环过程中关节盘中的应力分布。最后，该模型能够预测TMJ盘在由下颌创伤、手术或功能异常引起的各种载荷作用下的应力演变。
模型的几何数据取自一名健康男性患者的MRI和CT扫描图像。使用3D图像分割软件（AMIRA(®)）先后获得表面网格和体积网格。颅骨和下颌骨的骨成分、两个关节盘、颞下颌关节囊和韧带以及牙弓均作为独立的实体进行网格划分。将体积网格转移到有限元分析软件（FORGE(®)）中。为每个区域指定材料属性。闭口模拟的边界条件由颌骨肌肉的不同加载方向表示。分析了闭口状态下两个关节盘中的冯·米塞斯应力分布。
TMJ盘中的冯·米塞斯应力模式不对称，并且在颌骨运动过程中持续变化。在与其他物体接触的区域，关节盘表面达到最大应力。
咀嚼系统的三维有限元模型将能够模拟在导致关节损伤的一系列事件中似乎很重要的不同情况。
