IADR Abstract Archives
Effect of Chewing Speed on the Masseteric EMG-Force Relationship
Objectives: Chewing speed might affect the force-velocity property of jaw closing muscles.The purpose of the present study was to investigate the effect of chewing speed on the force-EMG relationship of the masseter muscles.
Methods: Ten healthy volunteers, aged 21-23, with Class I occlusion participated in the study. Chewing force was measured by a 3-mm thin U-shaped bite force transducer placed on the lower first molar on subjects’ preferred side. Surface EMG was used to record the activity of both masseter muscles and a sirognathograph was used to monitor jaw movements. In the first experiment, subjects chewed vertically on a silicone pad placed on top of the transducer at either 60 (slow) or 120 (fast) cycles/min and the relationship between IEMG (integrated EMG) and chewing force was determined. In the second experiment, the chewing force on a piece of paraffin wax was estimated from EMG at the same speed as in the first experiment.
Results: The average slope of the force-IEMG amplitude curve was significantly greater with slow chewing speed than the fast one (0.790±0.581 µV/N and 0.558±0.275 µV/N respectively). The force values predicted from the muscle activity on the working side during slow chewing yielded the best approximation of the actual chewing force (R= 0.95±0.70).
Conclusions: It was concluded that masseter muscles were more efficient during fast than slow chewing task. This could not be explained by the force-velocity property of the muscle.
Methods: Ten healthy volunteers, aged 21-23, with Class I occlusion participated in the study. Chewing force was measured by a 3-mm thin U-shaped bite force transducer placed on the lower first molar on subjects’ preferred side. Surface EMG was used to record the activity of both masseter muscles and a sirognathograph was used to monitor jaw movements. In the first experiment, subjects chewed vertically on a silicone pad placed on top of the transducer at either 60 (slow) or 120 (fast) cycles/min and the relationship between IEMG (integrated EMG) and chewing force was determined. In the second experiment, the chewing force on a piece of paraffin wax was estimated from EMG at the same speed as in the first experiment.
Results: The average slope of the force-IEMG amplitude curve was significantly greater with slow chewing speed than the fast one (0.790±0.581 µV/N and 0.558±0.275 µV/N respectively). The force values predicted from the muscle activity on the working side during slow chewing yielded the best approximation of the actual chewing force (R= 0.95±0.70).
Conclusions: It was concluded that masseter muscles were more efficient during fast than slow chewing task. This could not be explained by the force-velocity property of the muscle.