Masticatory strains on osseous and ligamentous components of the temporomandibular joint in miniature pigs.
Masticatory strains on osseous and ligamentous components of the temporomandibular joint in miniature pigs.
复制标题
小型猪颞下颌关节骨和韧带成分的咀嚼张力。
作者：
Z. J. Liu;S. Herring
旨在
本实验通过动物功能生物力学的研究，了解颞下颌关节（TMJ）的正常负荷，为TMJ紊乱的发病机制提供理论依据。
方法
测量了26只10月龄小型猪咀嚼过程中的骨应变和韧带变形。一半的受试者在5 - 6周前接受了左侧关节囊和关节盘与髁突连接的手术破坏。将玫瑰花应变片粘在靠近TMJ的鳞状骨的左侧表面、髁突颈和磨牙区下方的下颌体。将差动可变磁阻传感器（DVRT）放置在双侧关节的外侧囊组织中。在自然咀嚼过程中记录骨应变、韧带变形以及咬肌和翼外肌的肌电活动。
结果
在工作侧和平衡侧的所有动物中，咀嚼引起的骨应变主要由鳞骨部位的张力和其他部位的压缩引起。DVRT的测量结果显示，在动力冲程的最后阶段，外侧囊组织延长，在开放的初始阶段缩短，这几乎与骨应变的发展同时发生。膜盒中的应变范围为3%至25%，平衡侧的应变超过工作侧的应变。手术破坏并没有改变咀嚼侧偏好或骨应变，但观察到完整侧的韧带变形倾向于更广泛。此外，与对照组相比，咬肌与翼外肌活动的比例在受损侧较小，在完整侧较大。
结论
在咀嚼过程中，颞下颌关节的骨和韧带组件都受到应变，后者在平衡侧更变形。中断的外侧附着的影响不大的应变在骨质成分，但似乎增加了应变的胶囊和修改咀嚼肌活动的平衡。
AIMS
An animal study of functional biomechanics was undertaken to understand normal loading of the temporomandibular joint (TMJ) and to provide insight into the pathogenesis of TMJ disorders.
METHODS
Bone strain and ligamentous deformation were measured during mastication in 26 10-month-old minipigs. Half the subjects had undergone a surgical disruption of the left lateral capsular and disc attachments to the condyle 5 to 6 weeks previously. Rosette strain gauges were bonded to the left lateral surfaces of the squamosal bone near the TMJ, the condylar neck, and the mandibular corpus below the molar region. Differential variable reluctance transducers (DVRTs) were placed bilaterally in the lateral capsular tissue of the joints. Bone strains, ligamentous deformations, and the electromyographic activities of the masseters and lateral pterygoids were recorded during natural mastication.
RESULTS
In all animals on both working and balancing sides, mastication caused bone strains that were dominated by tension in the squamosal bone site and by compression in the other sites. Measurements from the DVRT revealed elongation of the lateral capsular tissue in the last phase of the power stroke and shortening in the initial phase of opening, which was almost simultaneous with the development of bone strain. Strain in the capsule ranged from 3 to 25%, with the strain of the balancing side exceeding that of the working side. The surgical disruption did not alter chewing side preference or bone strain, but a tendency toward more extensive ligamentous deformation on the intact side was observed. Furthermore, the ratio of masseter to lateral pterygoid activity was smaller on the disrupted side and larger on the intact side, in comparison to control pigs.
CONCLUSION
Both osseous and ligamentous components of the TMJ are strained during mastication, and the latter are more deformed on the balancing side. Disruption of the lateral attachment had little effect on strain in the osseous components but appeared to increase strain in the capsule and to modify the balance of masticatory muscle activity.