The pH change after HCl titration into resting and stimulated saliva for a buffering capacity test

Abstract

Background: Saliva collection can provide clinical information about individual patients. However, a correlation between ranking buffering capacity using resting and stimulated saliva is still unknown. The aim of this study was to evaluate the pH change after HCl titration into resting and stimulated saliva for a salivary buffering capacity test. Methods: Resting and stimulated saliva (by chewing paraffin wax) were collected from 80 patients. After the pH of both saliva samples was measured using a hand-held pH meter, the saliva samples were titrated with 0.1N HCl to evaluate the buffering capacity. Correlations of ranking buffering capacity (high, medium, low) between stimulated saliva and resting saliva with 30μL HCl titration and between stimulated saliva and resting saliva with 40μL HCl titration were statistically analysed by Spearman Rank Correlation Test (p<0.05). Results: At 50μL HCl titration, stimulated saliva buffering capacities were ranked into high (above pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). At 30-40μL HCl titration, the resting saliva buffering capacities were ranked into the same categories. Spearman Rank Correlation indicated significant positive coefficients for the stimulated saliva and resting saliva buffering capacity at 30μL titration and the stimulated saliva and resting saliva at 40μL titration. Conclusion: Stimulated saliva is more resistant to variation in pH change during HCl titration than resting saliva. Stimulated saliva sampling is a good method to determine buffering capacity during a comprehensive oral health assessment.