Van Eijden T M
Academic Center for Dentistry Amsterdam (ACTA), Department of Anatomy and Embryology, University of Amsterdam, The Netherlands.
J Dent Res. 1990 Mar;69(3):901-5. doi: 10.1177/00220345900690031401.
This study examined the way the masseter and the anterior and posterior temporal muscles of human subjects were activated when a bite force of constant magnitude was exerted at different teeth in different defined directions. Subjects were instructed to produce a bite force of a particular magnitude (250 N) and direction (vertical, anterior, lateral, posterior, or medial) using a three-component force transducer and a feedback method. Simultaneously, the EMG activity of the muscles was registered with use of surface electrodes. Unilateral bite forces were produced at the right canine, second premolar, and second molar. In addition, a bilateral vertical premolar bite was examined for comparison of activity levels of the muscles of both sides. The results showed that, on average, the activities of the right and left side muscles did not differ in a bilateral vertical bite. Moreover, in a unilateral vertical bite, there were no significant right-left differences. For all bite force directions, more muscle activity was required for production of a constant bite force at the anterior side of the dental arch than at the posterior side. An exception to this rule was the activity of the posterior temporal muscle in a posteriorly directed bite. There was a close relationship between the direction of bite force and jaw muscle activity. Variations in activity were small for the anterior temporal muscle and large for the posterior temporal and masseter muscles. All muscles that were studied were always active, even in directions in which they could be expected to act antagonistically.
本研究考察了在不同特定方向对人类受试者的不同牙齿施加恒定大小咬合力时，咬肌以及颞肌前束和后束的激活方式。受试者被要求使用三分量力传感器和反馈方法，产生特定大小（250 N）和方向（垂直、向前、向外侧、向后或向内侧）的咬合力。同时，使用表面电极记录肌肉的肌电图活动。在右侧尖牙、第二前磨牙和第二磨牙处产生单侧咬合力。此外，还检测了双侧垂直前磨牙咬合力，以比较两侧肌肉的活动水平。结果表明，平均而言，双侧垂直咬合时左右侧肌肉的活动没有差异。此外，在单侧垂直咬合时，左右侧也没有显著差异。对于所有咬合力方向，在牙弓前部产生恒定咬合力比在后部需要更多的肌肉活动。该规则的一个例外是后牙向后方咬合时颞肌后束的活动。咬合力方向与颌肌活动之间存在密切关系。颞肌前束的活动变化较小，颞肌后束和咬肌的活动变化较大。所有研究的肌肉始终处于活动状态，即使在预期它们会起到拮抗作用的方向也是如此。
