Development of New Bruxism Monitoring and Elucidation of Mechanism of Periodontal Destruction

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1. Development of a New Compact Bruxism Monitoring DeviceWe developed a new compact bruxism monitoring device, which had ease of application and auto- analyzing system. The size of the new device is 65mm x 100 mm x 35mm. It can be placed on the forehead, and 5 pick-up cables need to be connected to the electrodes with AND circuit that works only when both masseter muscles were activated. The device has 3 digital monitors that shows total bruxism time of right, left and both masseter muscles. It can objectively monitor the bruxism activities, and has less unpleasant feeling to the patients compared to the previous models, so that can be used when subjects are awake and sleeping. As the result of using the device to the cohorts, it was shown that the new device was useful for examining the bruxism activities during daytime and night.2. Study of the Relation between Periodontal Destruction and BruxismThe. difference of jaw movement, muscle activity and tooth contacts between nocturnal bru … More xism and conscious bruxism in daytime were compared by using the jaw movement recorder developed by Y.Katoet. The result showed that the jaw position and the jaw movement direction in the daytime and night was quite different.The destruction process of furcation areas of monkeys with experimental periodontitis and occlusal trauma were investigated clinically, radiographically and pathologically. It was concluded that furcation involvement would advance slowly at initial stage by inflammation and progress rapidly with combination of inflammation and occlusal trauma.The influence of bruxism on human molar furcation involvement was clinically investigated, In the first experiment, 45 patients with furcation involvement were examined, and in the second experiment, 37 patients were classified into two groups : the first group wore occlusal splints for more than 1 year ; the second group wore splints for short period, and clinical and bacteriological examination were performed. The result showed that the furcation involvement was more severe in the strong bruxism group. Furcation involvement in the first group improved considerably as compared to that of the second group. However, there was no difference in the bacterial ratio between the two groups. Therefore, it was suggested that nocturnal bruxism influences the progression of furcation involvement. Less