Influence of an experimental palatal plate on thermal perception

This study aimed to examine how coverage of the hard palate by an experimental palatal plate influenced thermosensation.

A total of 20 young adult volunteers were recruited from Osaka University Graduate School of Dentistry. An experimental palatal plate, 1.5mm in thickness, was made for each subject from acrylic resin. The stimulus water were either warmed to 40, 42, 44, 46, or 48 degrees C or cooled to 30, 26, 22, 18, or 14 degrees C in a constant-temperature water bath, and the control water were maintained at 37 degrees C. Subjects were instructed to retain the control water in their mouths for 5 s, then to spit it out and to repeat with the stimulus water. They then rated the intensity of stimulation of warmth or cold compared to the control water by the magnitude estimation method. Each stimulus was administered three times in random order. Two experimental conditions were set: with and without the experimental palatal plate.

Perceived thermal intensity was measured as the slope of the regression line for each condition (with or without the experimental palatal plate, cold or warmth). There was a significant difference between with and without the experimental palatal plate; the regression slope with the plate was shallower than that without the plate (warmth perception with plate=0.55+/-0.21 vs. warmth perception without plate=0.70+/-0.23, P<0.05; cold perception with plate=-0.33+/-0.14 vs. cold perception without plate=-0.39+/-0.11, P<0.05).

The findings suggested that a denture covering the hard palate obstructs thermal perception.