Influence of Repetitive Saliva Swallowing on Oral Moisture

Objectives: There are many patients who have oral dryness. The aim of this study was to investigate the influence of repetitive saliva swallowing on the measurement value of an oral-moisture-checking-device. Methods: The subjects of this study were 24 healthy adults (HA) and 8 patients with oral dryness (OD). Oral moisture was measured at the lingual mucosa (LM) and buccal mucosa (BM) using an oral-moisture-checking-device (Mucus®, Life Co., Japan) which can measure oral moisture within 2 seconds. The statistical analysis (Friedman test) was performed to compare the moisture before saliva swallowing (B), after swallowing saliva once (F), after swallowing saliva twice (S), and after swallowing saliva three times (T). Results: The average moisture at LM was 29.1±3.1% for B, 29.0±2.9% for F, 29.7±2.0% for S, and 30.1±2.4% for T on HA. There were statistically significant difference between the measurement value of B and T, and F and T (p<0.05). The average moisture at BM was 31.7±1.6% for B, 31.7±1.8% for F, 31.8±1.8% for S, and 32.2±1.3% for T on HA. A statistically significant difference was not found. The average moisture at LM was 25.1±5.0% for B, 24.8±5.7% for F, 24.4±6.9% for S, and 27.3±4.8% for T on OD. There were statistically significant difference between the measurement value of B and T, F and T, and S and T (p<0.05). The average moisture at BM was 29.7±2.0% for B, 29.8±1.7% for F, 30.0±1.4% for S, and 31.5±1.4% for T on OD. A statistically significant difference was not found. Conclusions: The results of this study made it clear that the measurement value at LM increased by repetitive saliva swallowing, and the reason would be due to the stimulation by the function of swallowing. It was suggested that one time saliva swallowing before the measurement did not influence the measurement value.