Yaka T
First Department of Prosthodontics, Faculty of Dentistry, Tokyo Medical and Dental University.
Kokubyo Gakkai Zasshi. 1994 Jun;61(2):275-89. doi: 10.5357/koubyou.61.275.
The effects of different occlusal position on the masticatory muscle function were investigated on 5 subjects. Two types of maxillary stabilization splints were fabricated in order to change the occlusal position. One type of the splints was to increase the occlusal height and the other was to shift the occlusal position laterally. The EMG activities of the masseter (M) and the anterior and posterior temporal muscles (AT, PT) were measured in various occlusal positions at 50% of maximal voluntary activity of the M and AT. The results were as follows: 1. When the occlusal height was increased. 1) The activity of the PT decreased in most subjects. 2) Asymmetry index (AI) of each tested muscle did not always indicate a similar value. 2. When the occlusal position was shifted laterally, 1) The activities of the ipsilateral AT and PT were higher than those of the contralateral side. 2) The AI of the AT and the PT changed gradually when the occlusal height was large while they changed greatly near the intercuspal position (IP) when the occlusal height was smaller. Therefore, the symmetry of the temporal muscle activity was thought to be influenced sensitively by the lateral shift of jaw position near the IP.
对5名受试者研究了不同咬合位置对咀嚼肌功能的影响。制作了两种类型的上颌稳定矫治器以改变咬合位置。一种矫治器是增加咬合高度，另一种是使咬合位置向侧方移动。在咬肌（M）和颞肌前束与后束（AT、PT）最大自主活动的50%时，于不同咬合位置测量其肌电图活动。结果如下：1. 当咬合高度增加时。1）大多数受试者的PT活动降低。2）各测试肌肉的不对称指数（AI）并不总是显示相似的值。2. 当咬合位置向侧方移动时，1）同侧AT和PT的活动高于对侧。2）当咬合高度较大时，AT和PT的AI逐渐变化，而当咬合高度较小时，它们在牙尖交错位（IP）附近变化较大。因此，认为颞肌活动的对称性受IP附近颌位侧方移动的影响较为敏感。
