[Effect of bite force on parotid secretion in human]

To determine the physiological roles of periodontal mechanoreceptors in parotid salivary secretion, we studied the effects of strength and frequency of unilateral bites on the salivary secretion from both sides of human parotid glands. Parotid saliva was collected bilaterally via modified Lashley cups, and the flow rate of parotid saliva was measured with a device using a strain gauge. The bite force was monitored with a pressure transducer. In the first experiment, subjects were constantly occluded for one minute at 80 strokes per minute at strengths of 5, 10, and 20 kg. In the second experiment, subjects were occluded for one minute at a constant force of 10 kg at frequencies of 20, 40, 80, and 120 strokes per minute, or subjects were continuously clenching for one minute. The flow rate of parotid saliva gradually increased with increasing bite strength, while it gradually decreased with increasing bite frequency. In unilateral bites, the salivary flow rate of the ipsilateral parotid gland was greater than that of contralateral parotid gland, at any strength and frequency. These results suggest that periodontal mechanoreceptors are involved in parotid salivary reflexes initiated by bite force stimuli.