Electromyographic estimtion of incompetent lip

第一部分青壮年样本包括49例阳性覆盖和覆牙合患者和17例开放咬合患者。两个双极表面电极连接在上下嘴唇的皮肤上。根据两个唇位之间的肌电活动的正值和负值的差值计算下颌静止位肌电活动的平均积分幅度。负值的受试者被评定为嘴唇合格，而正值的受试者则被认为嘴唇不合格。与下唇的降压肌相比，封闭嘴唇时，颧肌的肌电活动是有意义的。开放咬合组的所有受试者都有不称职的嘴唇。弱唇组较健唇组下颌平面陡峭，上、下颌切牙倾斜度较大。提示…在下颌静息位时颧肌肌电活动的差异。此外，唇部接触和分离为评价唇部功能提供了一个客观的标准，面部的垂直尺寸和切牙的倾斜度都会影响下唇功能。记录下唇和咀嚼肌在静息状态和咬合时的肌电记录。用方差分析(ANOVA)对正常唇组和非正常唇组的下唇肌电活动和头影测量进行统计学比较。不能唇组和张开咬合组的下唇肌电活动与静止位相关(r分别为-0.910、-0.980)，但在无功能唇组和张开咬合组中无明显变化。研究发现，嘴唇功能不全的受试者在下唇和咬肌之间表现出明显的功能协调。较少

Part 1Young adult samples consisted of forty nine subjects with positive overjet and overbite, and seventeen with open bite. Two bipolar surface electrodes were attached to the skin of the upper and lower lips. The mean integrated amplitude of the EMG activity at mandibular rest position with the based on positive and negative values of the difference in integrated EMG activity of the mentalis muscle between two lip positions. Subjects who showed negative value was calssified as having competent lips and those with positive value were lip incompetent. The EMG activity of the mentalis muscle was indicative in sealing lips as compared to that of depressor of lower lip. All subjects in the open bite group hadn incompetent lips. The incompetent lips group showed steeper mandibular plane as well as large proclination of maxilary and mandibular incisors than the competent lips group. It was suggested that the difference of the EMG activity of the mentalis muscle at mandibular rest position w … More ith the lips in contact and apart offers an objective criterion for the evaluation of lip competence and that vertical dimension of the face as well as proclination of the incisors can affect lower lip function.Part 2Sample consisted of forty-nine subjects with positive overjet and overbite, and seventeen skeletal open bite subjects which received orthognathic surgery. EMG recording of lower lip and masticatory muscles was taken at rest and during clenching with the lips in contact and apart. EMG activities of the lower lip and cephalometric measurements were statistically compared between the competent and incompetent lips groups using analysis of variance (ANOVA). EMG activity of the lower lip during clenching with the lips in contact decreased in the incompetent lips subjects but not in the competent lips subjects and it was correlated (r= -0.910, -0.980) with that at rest position in the incompetent lips and open bite groups. It was found that the incompetent lips subjects showed distinct functional coordination between the lower lip and masseter muscle. Less