Analysis of Tongue Pressure Production During Swallowing in Patients with Mandibular Prognathism after the Orthognathic Surgery

Abstract

Purpose:The purpose of this study was to consider the tongue pressure production during swallowing in patients with mandibular prognathism after orthognathic surgery. Methods:The subjects were 10 female patients with mandibular prognathism after orthognathic surgery(age range, 18y6m–25y10m; mean age : 22.6 years ; after surgery), 10 female volunteers with normal occlusion (age range, 20y0m–24y2m; mean age : 21.7 years ; normal occlusion), and 10 female patients with mandibular prognathism(age range, 16y3m–22y7m; mean age : 20.2 years ; mandibular prognathism patients). The tongue pressure in five parts at the time of swallowing 4 ml of tasteless and odorless jelly was measured after attaching sensor sheets on the palate of each subject. Features of tongue pressure waveforms, the time series of tongue pressure production, the duration of tongue pressure, and the maximum tongue pressure value were evaluated. Results:The tongue pressure waveforms showed a similar tendency between the after-surgery patients and the normal-occlusion patients. The tongue pressure waveform rose at each measurement location and peaked at 200–400ms. It then gradually declined and disappeared. The incidence of a double-peak tongue pressure waveform was more frequent in the mandibularprognathism patients. Although the time series of tongue pressure production was the same for the three groups, the maximum tongue pressure value at all channels was lower in the after-surgery group and the mandibular-prognathism patients than in the normal-occlusion patients. Conclusions:The tongue pressure waveform was due to changes of their morphological characteristics after orthognathic surgery. But the maximum tongue pressure value at each location was lower compared with patients with normal occlusion. These results suggest that, in patients with mandibular prognathism after surgery, the tongue as a whole may remain in a lower position during swallowing.