Biomechanical Study of Changes in the TMJ During Mandibular Functions

1.髁突与关节盂窝的位置关系利用计算机断层扫描系统，对颞下颌关节进行三维测量。在模型中测量髁状突与关节窝之间的最短距离。结果表明，该技术具有足够的准确性，是一种评价颞下颌关节紊乱病患者髁突与关节窝关系的有效方法.颞下颌关节盘的生物力学特性对8只成年狗的关节盘进行拉伸试验。结果表明：1）椎间盘呈现非线性的应力-应变关系，2）在150 gf/mm应力下，非线性曲线可用两条直线连接来描述，说明椎间盘在不同的应力作用下表现出不同的两种弹性，其生物力学行为在椎间盘的不同区域存在差异. Constr ...更多信息 颞下颌关节（TMJA）人干颅骨分析模型的建立将TMJA人干颅骨分为平行于法兰克福水平面的横切面。拍摄切片照片，并在醋酸纸上追踪。然后，对截面图进行二维离散化。最后，所有的图表都被垂直地建立起来，以开发一个模型。模型由2082个节点和1340个实体单元组成. TMJ中的应力分析开发的模型用于通过有限元法（FEM）进行应力分析。在分析之前，肌肉力被集成在模型中，模拟下颌骨的临床运动。为了进行分析，施加约500 gf的力以顺时针方向移动下颌骨。作为分析的结果，在髁突和关节盂窝内及其周围诱导了几乎均匀的拉伸应力。结果表明：（1）即使在下颌骨上施加简单载荷时，关节盘的应力分布在关节盘的前部和侧后部区域也是不同的;（2）与实际咬合力和咀嚼力相比，关节盘的应力大小是减小的，（3）顺时针方向移动下颌骨的力系容易引起椎间盘的内前复位。少

1. The Positional Relationship Between the Condyle and Glenoid FossaeThree-dimensional configuration of the TMJ was conducted with tomograms by use of a personal computer system. The shortest distance between the condyle and glenoid fossa was measured in the model. As a result, it was shown that the present technique had an enough accuracy and was an available method to evaluate the relation of the condyle to the glenoid fossa in orthodontic patients with temporomandibular disorders.2. Biomechanical Properties of the TMJ DiscArticular discs derived from eight adult dogs were used for tensile tests. The results revealed that 1) the disc exhibited non-linear stress-strain relationships, 2) the non-linear curve could be described by two straight lines connected at a stress of 150gf/mm. Thus, it was indicated that the disc experienced different two elasticity according to stresses applied to the disc and that its biomechanical behavior was different in different areas of the disc.3. Constr … More uction of Analytical Model of the TMJA human dry skull was divided into transverse planes parallel to the Frankfort horizontal plane. Photographs were taken of sections and were traced on acetate papers. Then, two-dimensional discretization was performed on the diagrams from the sections. Finally, all the diagrams were built up vertically to develop a model. The model consists of 2082 nodes and 1340 solid elements.4. Stress analysis in the TMJThe model developed was used for stress analysis by means of the finite element method (FEM). Before the analysis, muscle force was integrated in the model, simulation clinical movements of the mandible. For the analysis, an approximately 500 gf force was apllied to shift the mandible in the clockwise direction. As a result of analysis, almost uniform tensile stresses were induced in and around the condyle and glenoid fossa. Tensile and compressive stresses were produced at the anterior and lateral-posterior regions of the articular disc.Thus, it is shown that 1) the nature of stress distributions in the disc was different in different areas of the disc, even in loading with simple force applied to the mandible, 2) the magnitude of stresses in the articular disc was reduced in comparison with actual biting and chewing forces, 3) a force system to shift the mandible in the clockwise direction might induce easily medio-anterior reduction of the disc. Less