そしゃく運動に関する運動学的および筋電図学的検討 ＩＩ‐１． そしゃく運動相リズムおよび筋放電持続時間について

Abstract

In this study, the regularity of masticatory movement and the phase of muscle activity in a dentate subject with disclusion in his 20s were recorded simultaneously with the Saphon Visi-Trainer CII, a device for analyses of jaw movement, and the polygraph, a multipurpose monitoring/recording device.The following conclusions have been reached:(1)In the opening phase(I), the rhythm is just about the same in the early and middle periods.In the late period, the rhythm becomes signigcantly large.(2)In the closing phase (II), the rhythm is significantly large in the early period and just about the same in the middle and late periods.(3)In the occlusal phase(III), the rhythm is the smallest in the early period and it becomes significantly larger in the middle and late periods.(4)In the cycle(C), just about the same level is shown in the early and middle periods and significantly the largest in the lane periods.(5)I/C is just about the same in every period of the mastication.(6)II/C is significantly the largest in the early period and becomes significantly smaller in the middle and late periods.(7)III/Cis significantly the smallest in the early peri od, and becomes significantly larger in the middle and late period.(8)The number of masticatory stroke is the largest for ham and about the same for peanuts and pickled raddish.(9)Duration of muscular discharge in the closing phase (D1)is significantly the largest in the early period and it becomes smaller in the middle period and further smaller in the late period.(10) The duration of the muscular discharge in the occlusal phase(D2), are significantly the smallest in the early period, and becomes larger in the middle period and further in the late period.(11)D 1/D is significantly the largest in the early period and becomes smaller in the middle and periods.(12)D2/D is significantly the smallest in the early period and becomes larger in the middle and late periods.