Jiménez I D
Preventive Dental Science Department, Faculty of Dentistry, University of Manitoba.
J Oral Rehabil. 1987 Nov;14(6):591-8. doi: 10.1111/j.1365-2842.1987.tb00755.x.
The electromyographical (EMG) activity of masticatory muscles during full clenching in the retruded contact position (RCP) and intercuspal position (IP) with and without a posterior stabilizing splint was studied. The linear envelope EMG signal from three bilateral muscles was recorded (masseter, anterior temporal and posterior temporal). Thirty-seven subjects were evaluated. Clenching in the RCP without the splint and with the presence of an unstable occlusal contact inhibited the masseter muscle activity and reduced anterior temporal and posterior temporal muscle activity. The masticatory muscle activity returned to normal when clenching in the RCP with a splint that permitted stability in the dentition. EMG activity was the same in the IP with and without the splint. The results indicate that the determinant of maximal masseter isometric muscle contraction is the amount of stability in the dentition rather than the jaw position. If the dentition takes the major role of stabilizing the mandible, i.e., there is good intercuspation, the masseter muscle can exert maximal isometric contraction. If the stability is not provided by the dentition, i.e., there is a premature contact, the jaw muscles must contribute to the stabilization and reduce the magnitude of the maximal contraction to avoid damage to the structures involved in the compensatory stabilization.
研究了在后退接触位（RCP）和牙尖交错位（IP）时，佩戴和不佩戴后牙稳定 垫进行最大紧咬时咀嚼肌的肌电图（EMG）活动。记录了来自三块双侧肌肉（咬肌、颞前肌和颞后肌）的线性包络EMG信号。对37名受试者进行了评估。在RCP不佩戴稳定垫且存在不稳定咬合接触时紧咬，会抑制咬肌活动，并降低颞前肌和颞后肌的活动。当在RCP佩戴能使牙列保持稳定的稳定垫紧咬时，咀嚼肌活动恢复正常。在IP佩戴和不佩戴稳定垫时EMG活动相同。结果表明，咬肌最大等长收缩的决定因素是牙列的稳定程度而非颌位。如果牙列在稳定下颌方面起主要作用，即存在良好的牙尖交错，咬肌就能发挥最大等长收缩。如果牙列不能提供稳定性，即存在早接触，颌肌必须参与稳定并减小最大收缩幅度，以避免对参与代偿性稳定的结构造成损伤。
