The relationship between the oral mucosal wetness level and saliva production was examined using MucuseTM, an oral moisture-checking device of Murata Manufacturing Co., Ltd. The 117 subjects were patients with untreated xerostomia who visited participating centers regularly. Saliva production was analyzed using weight of saliva in a gum test, gum test weight values. The median （minimum-maximum） saliva weight was 6.0 （0-21.1） g and the median oral mucosal wetness level was 30.9 （6.7-36.0）. The correlation coefficient of oral mucosal wetness levels with gum test weight values was 0.202 （p＝0.029）. Using a standard gum test weight value of 10 g for xerostomia, the median oral mucosal wetness level was significantly lower in 92 subjects with a value lower than the standard compared to that in 25 subjects with higher values （30.8 （6.7-34.1） vs. 31.3 （28.1-36.0）, p＝0.017）. Receiver operator characteristics （ROC） analysis gave AUC＝0.654 （p＝0.017） at a cutoff value of 30.9, and oral mucosal wetness levels of 30.3 and 32.2 when sensitivity and specificity were ≥80％, respectively. The cutoff value for xerostomia was 30.3 and that for healthy persons was 32.2, suggesting a boundary zone from 30.4-32.1.
