Verification of working hypothesis on the mechanism of occurrence of the temporomadibular disorder in the experimental animal models

本研究的结果总结如下：1)兔可用于研究颞下颌关节紊乱病的发生机制。因为我们可以通过电刺激咀嚼皮质区(MCA)的不同部分来控制颌骨的运动模式。2)结合颌骨运动，通过去除关节窝顶端的方法，记录关节盘的运动过程。结果表明，去除关节窝的顶端并不会严重影响颌骨和关节盘的运动。然而，在刺激大脑中动脉外侧部诱发的磨削性颌骨运动过程中，由于视频的时间分辨率不足以及颌骨跟踪器的振动干扰了颌骨的运动记录，我们无法定量分析关节盘的运动与颌骨运动的关系。3)电刺激翼外侧肌上头(SUP)不会引起关节盘相对于髁突的位置变化，但刺激颧颌肌产生了明显的关节盘移位。提示颧颌肌在控制关节盘运动中可能起重要作用。

The results of the present study are summarized as follows ;1) Rabbit is useful for studying the mechanism of occurrence of the temporomadibular disorder. Because we can control the jaw movement pattern by electrical stimulation of the different portion in the masticatory cortical area (MCA). When stimulated in the medial part of the MCA,chopper-type jaw movement was induced and when stimulated in the lateral part of the MCA,grinding-type jaw movement was induced.2) In combination with jaw movements, we recorded video movie of the movement of the articular disk by removing the roof of the glenoid fossa. It appeared that removing the roof of the glenoid fossa did not seriously affect the movements of the jaw and disk. However we could not analysis in quantity the movement of the disk in relation to the jaw movement and the EMG activities of the masticatory muscles during grinding-type jaw movement induced by stimulation of the lateral part of the MCA.Because of insufficient time-resolution of the video movies and disturbed jaw movement record by vibration of jaw tracking equipment.3) Electrical stimulation of the superior head of the lateral pterygoid muscle (SUP) did not induce the positional change of the disk relative to the condyle but the stimulation of the zygomato-madibular muscle produced marked displacement of the disk. This suggests that the ztgomato-madibular muscle may play important role in the control of the movement of the disk.