KATTO Katsuhiko Aichi-Gakuin University School of Dentistry, Research Fellow, 歯学部, 助手 (10201419)
TANAKA Kiyoo Aichi-Gakuin University School of Dentistry, Research Fellow, 歯学部, 助手 (70175446)
MORI Takashi Aichi-Gakuin University School of Dentistry, Assistant Professor, 歯学部, 講師 (00159188)
|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1990 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1989 : ¥1,400,000 (Direct Cost : ¥1,400,000)
In order to establish a reliable means of objectively and accurately evaluating the masticatory masticatory function in daily practice, mandibular movements and EMG during mastication were recorded and the reproducibility of indices by processing the data were analyzed.
Ten subjects with natural dentitions were examined while chewing raisins, peanuts and chewing gum as test food. The recording was performed one time on each food a day, and repeated five days in total at three- to six-day interval.
The following seven indices were measured : (1) opening phase (Op), (2) closing phase (C1), (3) stopping phase (St), viz. the period when the mandible was stationary during occlusal contact, (4) cycle time (Cy), (5) duration of EMG activity (D), (6) duration of EMG silence (I), (7) the period of EMG silence (I_2), viz. the period from the end of EMG activity to the end of the stopping phase.
1. Inter-day fluctuation, except St and I_2 during chewing every food and C1, Cy, D and I in the case of peanuts, was measured and showed a statistically significant difference (p<0.05).
2. Using any food, except St and I_2, the mean values of subjects on the first day tended to be longer than that on subsequent days.
3. The mean range of inter-day fluctuation after the first day was the smallest in raisins.
4. It seams that using raisins as the test food would be useful when we apply the indices in the present experiment to the evaluation of the masticatory function.
5. With all the foods used, statistically significant positive correlations (p<0.05) were found between the cycle time and the other indices.
This suggested that if it is possible estimate these indices from the cycle time, we may be able to analyze the masticatory function of patients more easily during clinical examination.