Co-ordination pattern of masticatory muscle activities in temporo-mandibular disorders.

本研究的目的是了解颞下颌关节紊乱病患者咀嚼肌活动的协调模式。为了调节产生咀嚼肌活动的任务，在肌电记录过程中使用自制的换能器监测咬合力的大小和方向。然后，受试者被要求紧握图形终端上指示的特定咬合力的大小和方向，作为视觉生物反馈信号。咬合力的大小和方向对翼内侧肌活动均有显著影响(2因素方差分析，p&lt；0.05)。在前向或内侧咬合时，活动显著较高(学生-纽曼-科尔斯检验，p&lt；0.05)，而在后向或侧向咬合时，活性较低。当咬合力方向由垂直向前方和向中部改变时，翼外侧肌活动显著增加(p&lt；0.05)。但在后向与垂直方向之间，在侧向与垂直方向之间，翼点外侧活动度无明显变化。前人报道，咬肌和颞肌的活动与咬合力方向的变化有关，呈现出相互作用的模式。这些三维控制咬合力的咀嚼肌活动的协调模式可以为诊断颞下颌关节紊乱病提供标准标准。

The purpose of this study was to understand the co-ordination pattern of masticatory muscle activities in the temporomandibular disorders. In order to regulate the tasks producing masticatory muscle activities, bite force magnitude and direction were monitored with costom-made transducer during EMG recordings. Subjects were then asked to clench at the specific magnitudes and directions of bite force ndicated on a graphic terminal as visual biofeedback signals. Both the magnitude and the direction of bite force had significant effect on the medial pterygoid muscle activity (2-way ANOVA,p<0.05). The activity was significant higher (Student-Newman-Keuls test, p<0.05) during anteriorly or medially directed bite and lower during posteriorly or laterally directed bite. The lateral pterygoid muscle activity increased significantly (p<0.05), when the bite force direction changed from vertically to anteriorly, and to maedially. However, between the posterior and vertical direction, and betwen the lateral and vertical direction, the lateral pterygoid activity was not changed significantly. As reported previously, the masseter and the temporal muscles activities showed reciprocal pattern realted to the changes of bite force direction. These co-ordination patterns of masticatory muscle activities for controlling bite force three dimensionally could provide us the standard criterion in diagnosis of temporomandibular disorders.