The purpose of this study was to evaluate the reproducible of the FFT analysis for the EMG activities of the masticatory muscles. Three children (II A- II C) and three adults who have normal occlusal function were subjected. The EMG recordings were taken during positions of resting occlusion, clencing and tooth tapping of the subjects. Three parameters were chosen for the measuring points such as 1) frequency range (Hz),2) frequency of maximum peak (peak Hz),3) strength of maximum peak (peak dBV).
The results obtained in the present sudy were summarized as follows;
1) The two parameters such as frequency range (Hz) and peak (dBV) were found to be reproducible in the children and adults alike, while peak (Hz) showed some varieties within single day and day by day basis.
2) With increasing the biting force, the values of frequency range (Hz) and peak (dBV) also showed a tendency to increase, and when it was compared with the temporalis and masseter muscles, the temporalis muscle showed superior activities in children, while, the masseter in adults.
Although the discussions are still left if the measuring point adopted in the study is adequate. From the results obtained in the present sudy suggested that FFT analysis was considered to be effected method for evaluaing the activities of masticatery muscles both in children and in adults.