Quantitative assessment for stimulated saliva flow rate and buffering capacity in relation to different ages

Objectives To evaluate salivary flow rate and buffering capacity using a quantitative pH measurement among three broad age groups. Methods The population consisting of 117 patients was classified into three age groups: young, middle-aged, and elderly group. The volume of stimulated saliva after chewing gum was measured. Saliva samples were titrated with 0.1N HCl to evaluate the buffering capacity. Saliva pH change was measured directly using a hand-held pH meter. At the point of 50 μL of titrated HCl, individual salivary buffering capacities were ranked into one of the following three categories; high buffering capacity (above pH 5.5), medium buffering capacity (from pH 5.5 to 4.5), and low buffering capacity (below pH 4.5). Results χ2-test showed that the proportional distribution of individuals in the three buffering capacity groups was not statistically different among the age groups (p > 0.05). One-way ANOVA and Tukeyʹs HSD test showed the flow rate of stimulated whole saliva in the young group was significantly greater than that of the middle-aged and elderly groups (p < 0.05). Two-way ANOVA showed there was no significant interaction between the independent variables buffering capacity and age group (F = 0.419, p = 0.7950). One-way ANOVA and Tukeyʹs HSD test indicated the flow rate showed significant differences among the three age and buffering capacity groups. Conclusions Although a limited number of subjects were investigated in this study, the quantitative saliva assessment is useful as a screening method for different ages to identify patients with a low saliva flow rate and/or buffering capacity.