[Sensory receptors on oral thickness sensation]

The purpose of this study was to evaluate the role of the receptors connected with oral thickness perception. Twenty dentate volunteers participated in this study. The right second premolars were selected as test teeth. The thickness perception test was performed using aluminum foil. The experimental conditions were: 1) two types of occlusal contact positions; intercuspal position and teeth contact position of a single pair, 2) two types of closing velocities: "slow closure" and "fast closure" which were synchronized with 50 and 150/min metronome, and 3) application of local anesthesia to test teeth. The number of incorrect assessments for all trials and the proportion of correct assessments for actual trials were used for analysis. There were significant increases of incorrect assessments below 200 microns in "slow closure" at teeth contact position of a single pair. The minimum thickness of 80% of correct assessment was 100 microns both with and without anesthesia in "fast closure" at teeth contact position of a single pair. There were significantly fewer incorrect assessments in "fast closure" than in "slow closure" with anesthesia at teeth contact position of a single pair. These findings suggest that the closing velocity may influence oral thickness perception.