Abstract
The studies about the relationship between electromyographic (EMG) activities and jaw position were made by many researchers. But there were few practical devices for detecting the jaw position by means of electromyographic activities. In this study a simplified electromyographic horizontal jaw position detector for clinical use was developed. The device gets the EMG signals from four muscles: temporalis and masseter muscles on both sides respectively, by means of the surface electrodes. The output is the position of a spot in a two dimensional plane showing the estimated position of the mandible calculated by the EMG signals in real time. In the plane the vertical axis represents the anterior-posterior position and the horizontal position represents the right-left position of the mandible. For the sake of clinical use, it was made by analog devices and in a small size. The response appears in real time, so we can estimate the position when a patient exhibits a clenching force.
In the basic trial of this device we concluded that this device has sufficient performance for practical use for detecting the horizontal jaw position. Moreover, it has a potential to know the temporal aspects of the muscle activity during masticatory movement.
