关节盘前移位对颞下颌关节功能影响的生物力学实验和数值研究

Anterior disc displacement (ADD) is the most common Temporomandibular joint (TMJ) diseases. The major symptoms of ADD are joint pain, abnormal joint tone and movement disorders of the mandible. ADD could be caused by many factors, but the etiopathogenesis is still unclear. The movements and loading of TMJ were proved to be closely related with ADD, but the specific mechanical parameters were still not known. This project is a biomechanical study about the influence of ADD on the function of TMJ, which is divided into three aspects. (1) The precisions of fluoroscopic system and finite element analysis will be obtained through animal test. (2) The animal models for ADD will be developed through long-term big opening. And the influence of ADD on the structure and the motion trail of TMJ, the contact stress and area between discs and articular cartilages, and the maximum and minimum principal stress distributions in the TMJs will be analyzed through fluoroscopy, morphological measurement, finite element analysis and Micro-CT. Then the relationship between ADD and the movements and loading of TMJ will be discussed. The effects of the splints and surgeries on ADD will also be studied. (3) Twenty subjects with ADD and ten asymptomatic subjects will be recruited. With the combination of CBCT, fluoroscopy and finite element analysis, the influence of ADD on the motion trails and the stress distributions of the TMJs will be obtained. This project will help to better understand the biomechanics and the prevention and therapy of ADD.

关节盘前移位（ADD）是最常见的颞下颌关节（TMJ）疾病，会引起关节弹响、疼痛和下颌运动受限等，严重影响生活质量。TMJ运动和负荷与ADD密切相关，而其发病机理仍不十分清楚，哪些参数与关节盘前移位直接相关也不明确。本项目围绕ADD对TMJ功能的影响展开生物力学研究，包括：1）通过动物实验，验证动态X光系统和有限元分析的准确性。2）采用长时间大张口的方式创建ADD的动物模型，将动态X光技术、有限元分析和Micro-CT相结合，研究ADD对TMJ结构、运动轨迹及关节盘和关节软骨层的接触应力和面积、最大/最小主应力分布等的影响，探讨ADD与TMJ运动和负荷的内在联系，并研究颌垫对ADD的治疗效果。3）选择ADD患者和正常人，将CBCT、动态X光技术和有限元分析相结合，采用相同的方法分析ADD对TMJ的运动轨迹和应力分布的影响，并检验动物实验结果与临床的相关性，为ADD的防治提供理论依据。

关节盘前移位（ADD）是最常见的颞下颌关节（TMJ）疾病，会引起关节弹响、疼痛和下颌运动受限等，严重影响生活质量。TMJ运动和负荷与ADD密切相关，而其发病机理仍不十分清楚，哪些参数与关节盘前移位直接相关也不明确。本项目围绕ADD对TMJ功能的影响展开生物力学研究，得到关节盘前移位引起髁突运动轨迹的抖动，降低了下颌的运动范围和关节间隙，导致髁突对关节盘的挤压增大。通过调整颌位改变髁突在关节窝中的位置，明显增加了关节间隙（11.2-66.5%），髁突运动轨迹趋于平滑，TMJ内各结构的峰值应力明显低于治疗前，且应力分布规律更接近于对照组。可见，咬合板通过调整颌位改变了TMJ的生物力学环境，动态关节间隙和关节盘接触应力是重要控制参数，优化的治疗方案有助于关节盘复位和症状减轻。为了便于临床通过形态学和运动学参数去预测应力，可用MJS（内间隙）和AJS（前间隙）来预测关节盘对应区域的应力，用MJS和LJS（外间隙）来预测髁突对应区域的应力。关节盘应力与髁突位移可拟合出二次曲线，有助于辅助医生在知道下颌运动及髁突位移的情况下评估关节内应力。另外，研究发现，双侧TMJ应力的不对称与面部不对称密切相关，关节盘最小主应力与颌骨偏斜距离成正比。