Objective The purpose of this study was to compare the effects of different concentrations of green tea on salivary flow rate and pH value. Methods 20 healthy college students aged from 18 to 25 were included in this study, at State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University. Salivary flow rate and pH value were measured between 21: 00 and 22: 00 after drinking water, low, medium, and high concentration of green tea. Results Female salivary flow rates in low and medium concentration group were significant higher than that in high concentration group and water group (F＝5.20, P < 0.01). There was no significant difference in male sali⁃ vary flow rates among 4 groups (F＝1.810, P＝0.143). Salivary pH value in 3 green tea groups were lower than that in water group (F＝3.50, P＝0.02), with no significant difference among them. Conclusion Low and medium concentra⁃ tion green tea prevent decrease of salivary flow rate in healthy women but not in males. Salivary pH lowers after drink⁃ ing different concentrations of green tea.
