Hu Kai, Qiguo Rong, Fang Jing, Mao Jeremy J
Tissue Engineering Laboratory, Department of Orthodontics, University of Illinois at Chicago, 60612, USA.
Med Eng Phys. 2003 Mar;25(2):107-13. doi: 10.1016/s1350-4533(02)00191-1.
The present study was undertaken to test a hypothesis that the addition of articular fibrocartilage in the condyle of the temporomandibular joint reduces three-dimensional stress distribution in the condyle, the disc and articular eminence. A three-dimensional, nonlinear finite-element model was developed for analysis of joint loading before and after the addition of condylar fibrocartilage to the osseous mandibular condyle reconstructed from spiral computer topography data. In the model, each of the disc, condyle and articular eminence was arbitrarily divided into five regions: the anterior, posterior, medial, lateral and central. Von Mises stresses that in virtually all regions of the disc, condyle and articular eminence became lower after the addition of condylar fibrocartilage. Especially remarkable was the approximately four-fold reduction in von Mises stresses in the anterior, central and medial regions of the mandibular condyle. In comparison, only slight to moderate stress reductions occurred in the disc and articular eminence, suggesting that condylar fibrocartilage absorbs considerable stresses and likely dampens more loads than the disc and articular eminence. The mandibular condyle demonstrated the largest total displacement in all directions after the addition of articular fibrocartilage, followed by the disc and articular eminence. We conclude that the addition of articular fibrocartilage primarily reduces loading of the mandibular condyle, rather than the disc and articular eminence. These findings lead to a hypothesis that the mandibular condyle more likely functions as a shock absorber than the disc.
本研究旨在验证一个假设，即颞下颌关节髁突添加关节纤维软骨可降低髁突、关节盘和关节结节中的三维应力分布。基于螺旋计算机断层扫描数据重建的骨性下颌髁突，在添加髁突纤维软骨前后，建立了一个三维非线性有限元模型来分析关节负荷。在该模型中，关节盘、髁突和关节结节均被任意划分为五个区域：前部、后部、内侧、外侧和中央。添加髁突纤维软骨后，关节盘、髁突和关节结节几乎所有区域的冯·米塞斯应力均降低。尤其显著的是，下颌髁突前部、中央和内侧区域的冯·米塞斯应力降低了约四倍。相比之下，关节盘和关节结节的应力仅出现轻微到中度降低，这表明髁突纤维软骨比关节盘和关节结节吸收了更多的应力，可能缓冲了更多的负荷。添加关节纤维软骨后，下颌髁突在各个方向上的总位移最大，其次是关节盘和关节结节。我们得出结论，添加关节纤维软骨主要降低了下颌髁突的负荷，而非关节盘和关节结节的负荷。这些发现引出了一个假设，即下颌髁突比关节盘更有可能起到减震器的作用。
