Influence of swallowing saliva repeatedly on oral moisture

The aim of this study was to examine the influence of repetitive saliva-swallowing for the level of oral moisture using an oral-moisture checking device. Subjects were 24 healthy adults (HA) and 20 patients with oral dryness, 10 of whom had Sjögren syndrome or who had undergone radiation therapy (ODSR) and 10 who had not experienced ODSR (ODNSR). Oral moisture was measured before swallowing saliva (B), and after swallowing saliva once (F), twice (S), and three times (T). Oral moisture was measured at the lingual mucosa using an oral-moisture checking device. Statistical analysis was performed using the Friedman test. Oral moisture of the lingual mucosa of the HA differed significantly between B and T, and F and T, and the oral moisture level tended to be higher the more times saliva was swallowed. However, oral moisture of lingual mucosa in the ODSR was not different at the different times of measurement, but the level of oral moisture tended to be lower the more times saliva was swallowed. Oral moisture of the lingual mucosa in the ODNSR differed significantly between B and T. The trends for the changes of the oral moisture level in the ODNSR were similar to those in the HA. The results of this study show that swallowing saliva repeatedly could lead the increase of oral moisture in HA and ODNSR not in ODSR.