Tongue pressure on loop of transpalatal arch during deglutition.

The purpose of this study was to measure tongue pressure exerted on the loop of the transpalatal arch (TPA) during deglutition and to consider the influence of the distance of the loop of the TPA from the palatal mucosa and the anteroposterior position of the loop. Tongue pressures of 4 subjects with normal occlusion were measured with subminiature pressure sensors fixed on the TPA. The distances from the palatal mucosa to the surface of the pressure sensor were set at 2, 4, and 6 mm. The loop of the TPA was placed at the level of the middle of the maxillary second premolars (P), first molars (M1), or second molars (M2). Nine types of TPA devices were measured for each subject. The maximum recorded tongue pressure was taken from each act of deglutition. The minimum pressure value was exerted at position P when the distance from the palatal mucosa to the surface of the pressure sensor was 2 mm. The maximum value was obtained at position M2 and a distance of 6 mm from the palatal mucosa. When distances of 2, 4, and 6 mm were compared, significant differences between 2 and 4 mm, and between 2 and 6 mm were found. Significant differences were observed in comparisons between the positions P and M1, M1 and M2, and P and M2.