The Study of Jaw Movements and Muscle activity in Bruxism during Sleep.

本研究的目的是发展一种新的方法来分析睡眠时颌部运动和牙齿运动。开发了一种二维（前后侧）下颌运动记录系统来评估睡眠时的磨牙。对年龄在25 ~ 39岁的4名男性和3名女性成年志愿者的下颌运动数据进行了分析。肌电图显示咬肌和颞肌的活动情况。所得结果如下：1)该系统能够记录磨牙和咬牙时的下颌运动。在每个被试中，根据下颌运动模式将磨削行为分为多达三种类型，但在某些类型的磨削行为中，下颌运动模式是相似的。2)睡眠时握紧体位为中心咬合，其他为侧卧体位。在磨牙模式的颌部运动轨迹上观察到许多咬合姿势。采用单位脉冲技术的牙齿移动度测量系统Periotest<encircledR>作为打击仪器。使用一个轻量级加速度计（0.15g）检测牙齿的共振频率。采用快速傅里叶变换对数据进行分析。分别用人工牙和牙周组织对模型的牙齿活动度进行测定。并对6名25 ~ 35岁、牙周组织健康的成年男性志愿者的7个上颌中切牙进行了测量。模型研究结果表明，该系统获得的共振频率与人工支撑骨的高度、人工牙周韧带的宽度和人工牙周韧带的弹性有较高的相关性。另一方面。Periotest值没有。体内实验结果显示，F1和F2的平均共振频率分别为1300 (]SY+-[) 207 Hz和2805 (]SY+-[) 366 Hz。综上所述，本研究中使用的测量系统有助于客观评价颌骨运动和牙齿活动。

The purpose of this study was to develop a new method for analyzing jaw movements during sleep and tooth mobility. A two-dimensional (antero-posterior and lateral) jaw movement recording system was developed assess bruxism during sleep.The jaw movement data of 4 male and 3female adult volunteers, 25 to 39 years of age were examined. In addition, data for masseter and temporalis muscle activity were obtained by EMG.The results obtained were as follows ; 1) This system was able to record jaw movements during grinding and clenching. In each subjects, grinding was divided into as many as three types according to the jaw movement pattern, but the pattern of jaw movements were similar in some types of grinding. 2) The clenching positions during sleep were centric occlusion and other lateral positions. Many clenching positions were observed on the locus of jaw movements of grinding patterns.The tooth mobility measurement system using a unit pulse technique, Periotest<encircledR> was used as a percussion instrument. And a light-weight accelerometer (0.15g) was used for detection of the resonance frequency from a tooth. Analysis of data was performed by fast Fourier transform. The tooth mobility were measured in the models with an artificial tooth and periodontal tissues. And measured in 7 maxillary central incisors of the 6 male adult volunteers with healthy periodontal tissues, 25 to 35 years of age.As the results of the model investigation, the resonance frequency obtained by this system showed high correlation with height of artificial supporting bone, with width of artificial periodontal ligament and with elasticity of artificial periodontal ligament. On the other hand. Periotest value was not. Moreover, as the results in vivo, the average resonance frequencies F1 and F2 were 1300 (]SY+-[) 207 Hz and 2805 (]SY+-[) 366 Hz respectively.From above results, the measurement system used in this study was useful for objective evaluation of jaw movement and tooth mobility.