Development of evaluating system of bruxism by imaging physiological and biochemical characteristics of masticator muscles.

1. 为了评估磨牙症的特性，我们利用医学成像技术评估了咀嚼肌的代谢和生理生化特征。首先用MRI评价通过咬合模式的差异判断某一类型的咀嚼肌是否活动。我们认为可以用T2值来识别活动的咀嚼肌。我们研究了显示肌肉血流的多普勒超声是否有助于评估咬肌的代谢，以及作为医学成像通常用于评估咬肌代谢的31P-MR谱。多普勒超声显示的结果与31P-MR光谱的结果相关。建议用多普勒超声评价肌肉疲劳收缩和恢复情况。我们评估了表观弥散系数（ADC）和T2值的变化是否提示咬肌收缩。ADC对咬合变化敏感。我们建议T2值和adc可用于评估伴随磨牙症的肌肉疲劳和损伤。本研究的目的是评估在静息和颌开闭期间进行的DT MRI是否可以检测到水扩散的变化。MM扩散特征值对颌骨位置敏感。肌肉纤维的募集，特定于颌骨位置，反映了肌肉扩散参数的不同变化。

1. Regarding to assess the properties of bruxism, we evaluated metabolism, and physiological and biochemical characteristics of masticator muscles using medical imaging. At first, it was evaluated whether a kind of mobilized masticator muscles by the difference of occlusal pattern was judged using MRI. We considered that mobilized masticator muscles could be identified using T2 value.2. We studied whether Doppler ultrasonography presenting blood flow in muscle was useful for evaluating the metabolism of masseter muscle as well as 31P-MR spectroscopy which was performed generally for evaluating metabolism of it as medical imaging. Doppler ultrasonograpy presented findings in correlating to ones of 31P-MR spectroscopy. It was suggested that contraction and recovery from fatigue of the muscle could be evaluated using Doppler ultrasonography, also.3. We evaluated whether change of apparant difussin coeficient (ADC) and T2 value by clenching suggested contraction of masseter muscle. ADC was sensitive to changes by clenching. We suggested that T2 valus and ADCs may be used to evaluated muscle fatigue and injuries that accompany bruxism.4. The aim of this study was to assess whether water diffusion changes could be detected by DT MRI performed at rest, and during jaw opening and closure. The eigen values for diffusion of the MM were sensitive to jaw position. Recruitment of muscle fibers, specific to jaw position, reflects the different changes in muscle diffusion parameters.