Association between the functional-jaw orthopedic forces of the activator and the construction bites

已经提出了几个假说来解释激活剂的作用方式。由于矫治器设计最易变的方面是施工咬合，因此可以在此基础上评估治疗效果。此外，结构咬合决定了下颌骨的矢状和垂直位移，以及矫治器的激活程度和方向。本研究的目的是研究激活器的功能颌骨矫形力与结构咬合的关系。设计了四种类型的激活器，以在2、4、6和8 mm的切迹间距离处将下颌骨缩回到边缘到边缘的前后关系。花环应变计被放置在激活器的中间平面。同时检测肌张力、肌电和脑电。为了检查与劳损的关系，记录了咬肌和颞肌前纤维的肌电活动。以便对睡眠阶段进行评分。脑电(C3-A2)、肌电活动。结果如下：1.随着咬合高度的增加，眼球的最大应变值增大，旋转角度由原来的位置顺时针旋转。2.几种咬合方式下的肌电活动可分为上咬肌、颞上肌、上咬肌和颞肌三种类型。在四种结构咬合方式下，上咬肌和颞肌的最大应变是肌电活动模式中最大的。其中以颞上肌的角度最大。

Several hypotheses have been proposed to explain the mode of action of the activator. Since the most variable aspect of appliance design is the construction bite, the effect of treatment could be evaluated on this basis. Furthermore the construction bite determines the sagittal and vertical displacements of the mandible and the degree and direction of appliance activation.The purpose of this study was to investigate the relationship between the functional-jaw orthopedic forces of the activator and the construction bites.Four children with functional Class III malocclusion were used as the subjects. Four types of the activator were designed to retract the mandible to an edge-to-edge anters-posterior relationship at the 2, 4, 6, and 8mm interincisal distances. The rosette straingauges were set into the median plane of the activator. Simultaneously, strain, efectromyogram(EMG), and electroencephalogram(EEG) were checked. For examination of the relationship with strain, EMG activity was recorded from the masseter muscle and the anterior fibers of the temporalis muscle. In order to score the sleep stages. EEG(C3-A2), EMG activity from mentalis muscle. and eye movements(EMG from lateral to the outer canthus) were recorded.The results were as follows; 1.With the higher construction bite, the magnitude of maximum strain was increased, and the rotated angle was turned from the original position with the clockwise rotation. 2.In the aspect of EMG activities under several kinds of construction bites, they could be divided into three patterns, superior masseter muscle, superior temporalis muscle, and both the superior masseter and temporalis muscle. Under four types of construction bites, the magnitude of maximum strain in the pattern of both the superior masseter and the temporalis muscle was the greatest of the EMG activity pattern. Moreover the angle of it in that of superior temporalis muscle was the largest.