The Study on the Mechanism of Temporomandibular Joint Sound.

本研究的目的是研制一套能够同时记录6个自由度的下颌运动、包括翼外下肌和颞下颌音在内的颌肌多通道肌电的颌骨功能诊断系统，并利用该诊断系统探讨TMJ音的发生机制。在这个项目的第一年，在身体上进行了初步研究后，建立了一种用细丝电极记录翼外下肌活动的口腔内方法。同时记录6个自由度的下颌运动和翼外下肌的肌电活动。这种方法以前从未在世界上被尝试过。用该系统对8名受试者进行了研究，结果如下：1.根据前移位观察翼外下肌的活动时，其活动量受其平移速度或位置的影响。在下颌骨最慢的张开运动过程中观察到一个例外。翼外肌的活动发生在同侧髁突前移开始或之前，最终建立了TMJ录音方法，完成了颌骨功能诊断系统。该诊断系统可以有效地研究下颌关节的路径偏转情况、在点击过程中的运动速度变化以及TMJ的发声机制。

The purpose of this study was to develop a diagnostic system of jaw function which is able to record jaw motion with 6 degrees of freedom, multichannel EMG of jaw muscle including inferior lateral pterygoid muscle and temporomandibular sound simultaneously ; and to investigate the mechanism of TMJ sound with this diagnostic system. In the first years of this project, an intraorally recording method of inferior lateral pterygoid muscle activity with fine wire electrodes was established after a preliminary study in cadavers. Jaw motion with 6 degrees of freedom and EMG activity of inferior lateral pterygoid muscle were recorded simultaneously. This method had never before been attempted in the world. Eignt subjects were studied using this system with the following results :1. When the activity of inferior lateral pterygoid muscle was observed according to the forward translation of the condyle, the amount of its activity was influenced by the condyle's translation speed or position.2. An exception was observed during the slowest opening movement of mandible. The onset of activity of the lateral pterygoid muscle occurred at or before the beginning of forward translation of the ipsilateral condyle.Finally, TMJ sound recording method was established and the jaw function diagnostic system was completed. The diagnostic system is efficient in investigating the presence of condyle path path deflection, change of speed of condylar movement during clicking and the TMJ sound mechanisms as well.