TMJ FUNCTION AND MECHANICS--EXPERIMENTAL MODELS

描述：这项工作的长期目标是了解 颞下颌关节的生物力学环境， 阐明环境的改变如何导致重塑或 退化 本项目是进一步工作的前提， 为了满足研究界对经验证的动物的需求， 颞下颌关节功能的生物力学模型。 双管齐下的协同攻击 本文提出 首先，小型猪将被确立为一种动物 功能研究的模型。 第二，本实验系统与 与计算机模拟的优势联系在一起。 如果模拟是 成功地再现了清管器中的关节载荷和运动模式， 并预测由扰动引起的变化，然后使用这种 人体模拟将获得相当大的可信度。 将讨论四个具体目标。 具体目标1是表征 猪颞下颌关节骨和软组织成分的负荷和运动 在正常的功能。 这些研究将涉及生理学 测量骨骼的内部压力和表面应变， 韧带组织的张力和肌肉活动。 年龄和性别 将检查效果。 TMJ骨组件上的压缩载荷 将被量化。 具体的假设是 测试的结果是，胶囊及其与骨的连接处于张力下， 在不对称的下颌运动中。 具体目标2是确定骨的机械性能， 猪颞下颌关节的软组织成分。 体外试验将用于 确定每个组织的硬度和强度。 骨软组织 制备将用于评估软的粘弹性性质， 组织及其附件。 预计最薄弱的环节， 该系统是韧带组织到骨中的附件，特别是 关节盘和关节囊与关节外侧极的连接 髁状突 预计还将提高其强度和刚度 韧带和附件的椎间盘是更大的青春期后男性比 女性，并将随着年龄的增长，在两个性别。 具体目标3是建立猪的动态和静态计算机仿真 使用从上述研究中获得的信息进行TMJ运动和负荷。 验证测试将确定模型性能的可接受性， 整个实验条件。 预计这些模型将 有效预测椎间盘运动、韧带拉伸和髁突 菌株 他们将提供额外的，不可记录的物理数据，解释 机械事件，并表明未来计算机的潜在价值 模拟人类颞下颌关节。 具体目标4是研究细胞 对机械环境的反应。 中断后， 横向附件，将进行长期研究， 组织适应（重塑）或失败。 细胞更新，高度硫酸化 将比较糖胺聚糖（GAG）含量和胶原蛋白组成， 对照 韧带组织在张力增加的情况下 增加细胞复制和I型胶原蛋白合成，但减少 硫酸化GAG含量;预计张力降低具有相反的 结果 此外，重塑附件预计将有更多的III型 胶原蛋白，特别是在青春期后的雌性动物中。 重构是 预计在较年轻的年龄组中最有效。

DESCRIPTION: The long-range goal of this work is to understand the biomechanical environment of the temporomandibular joint (TMJ) and to elucidate how alterations in that environment lead to remodeling or degeneration. The present project is prerequisite to further work, and aims to address the need of the research community for validated animal and biomechanical models of TMJ function. A double-pronged, coordinated attack is proposed. First, the miniature pig will be established as an animal model for functional studies. Second, this experimental system with be linked with the strengths of computer simulation. If the simulations are successful in reproducing joint loading and movement patterns in the pig, and predicting changes resulting from perturbations, then use of such simulations in humans would gain substantial credibility. Four specific aims will be addressed. Specific aim 1 is to characterize the loads and movements of the bony and soft tissue components of the pig TMJ during normal function. These studies will involve physiological measurement of internal pressures and surface strains from the bones, tensions in ligamentous tissues, and muscle activity. Age and gender effects will be examined. Compressive loads on the TMJ bony components during chewing movements will be quantified. The specific hypothesis to be tested is that the capsule and its attachments to bone are under tension during asymmetric jaw movements. Specific aim 2 is to determine the mechanical properties of the bony and soft tissue components of the pig TMJ. In vitro testing will be used to determine stiffness and strength of each tissue. Bone-soft tissue preparations will serve to assess viscoelastic properties of the soft tissues and their attachments. It is expected that the weakest points of the system are the attachments of ligamentous tissue into bone, specifically the attachments of the disc and capsule into the lateral pole of the condyle. It also is expected that the strength and stiffness of the ligaments and attachments of the disc is greater in postpubertal males than females, and will increase with age in both genders. Specific aim 3 is to construct dynamic and static computer simulation of pig TMJ movements and loads using information gained from the above studies. Validation tests will determine the acceptability of model performances for the entire range of experimental conditions. The models are expected to make valid predictions of disc motions, ligament stretch, and condylar strains. They will provide additional, unrecordable physical data, explain mechanical events, and indicate the potential value of the future computer simulations of the human TMJ. Specific aim 4 is to investigate cellular responses to the mechanical environment. Following interruption of the lateral attachments, longer-term studies will be conducted to allow joint tissues to adapt (remodel) or fail. Cell turnover, highly sulfated glycosaminoglycan (GAG) content and collagen composition will be compared to controls. Ligamentous tissues under increased tension are expected to show increased cell replication and type I collagen synthesis but decreased sulfated GAG content; decreased tension is expected to have the opposite results. Further, remodeling attachments are expected to have more type III collagen, particularly in postpubertal female animals. Remodeling is expected to be most effective in the younger age group.