Lowe A A, Johnston W D
Am J Orthod. 1979 Nov;76(5):565-76. doi: 10.1016/0002-9416(79)90260-4.
In order to investigate the effect of mandibular rotations in human subjects, the electromyographic activity from the left GG, left masseter, and left orbicularis oris muscles was recorded during voluntary opening movements of the mandible that were monitored by an electronic transducer. For each muscle, a computer-based system was used to calculate a threshold incisor-separation position corresponding to a 20 percent increase in base line muscle activity. The mean threshold level for the GG muscle in a sample of twenty subjects with normal occlusions was 53.0 percent (S.D. +/- 22.8)of maximum jaw opening. By contrast, a sample of nine subjects with anterior open-bite malocclusions had a statistically significant (p less than 0.001) lower mean threshold of 5.9 percent (S.D. +/- 4.5) of maximum jaw opening. No significant differences in masseter or orbicularis oris muscle activity were found between the two samples. Since postural tongue activity could play an important role in the development of the anterior dentition, the lower threshold for the GG muscle activity in response to jaw opening in anterior open-bite subjects may be of significant clinical importance.
为了研究下颌旋转对人体受试者的影响，在由电子传感器监测的下颌自主开口运动过程中，记录了左侧翼外肌、左侧咬肌和左侧口轮匝肌的肌电活动。对于每块肌肉，使用基于计算机的系统计算出与基线肌肉活动增加20%相对应的阈值切牙分开位置。在20名咬合正常的受试者样本中，翼外肌的平均阈值水平为最大张口度的53.0%（标准差±22.8）。相比之下，9名前牙开颌错颌受试者的样本，其平均阈值在统计学上显著较低（p小于0.001），为最大张口度的5.9%（标准差±4.5）。在两个样本之间，未发现咬肌或口轮匝肌活动有显著差异。由于姿势性舌活动可能在前牙列发育中起重要作用，前牙开颌受试者中翼外肌活动对张口反应的较低阈值可能具有重要的临床意义。
