抄録
The purpose of this study was to investigate EMG profiles of masticatory muscles in orthognathic surgery patients with mandibular prognathism during deliberate unilateral gum chewing.
Vertical jaw movement and EMG activities from bilateral anterior temporal, masseter, and anterior belly of digastric muscles were recorded simultaneously from 12 healthy adults and 12 patients. EMG signal was divided according to the period of the maximum opening position of vertical jaw movement. EMG profiles of the chewing stroke were accomplished by normalizing each period to 100%. Normalization was achieved by setting the mean value of each EMG over the chewing cycle to 100%. The relationship of the EMG profile between normal subjects and patients was evaluated. The degree of similarity and the displacement for each EMG profile in all muscles was investigate by using a cross-correlation technique.
The results were as follows:
1. EMG profiles of patients were different for the “Peak” vale and “Duration” of the activity from those of normal subjects.
2. The similarity was little, and great displacement was found in patients.
3. In patients, the similarity and displacement of EMG profiles had large value on the working side.
