Intake of Acidic Beverages: Effect on Salivary pH Over Time

Objectives: Observational studies support an association between acidic beverage consumption and dental erosion. In this context, titratable acidity of the beverages and saliva buffering capacity are important factors. This clinical trial was undertaken to monitor salivary pH after the intake of acidic beverages.
Methods: After approval by the local ethics committee, 8 participants were enrolled and had their whole saliva assessed for flow, pH and buffer capacity. According to a crossover layout, participants imbibed 15mL of orange juice (pH 3.6), cola-type soft drink (2.4) and water added of 5% sucrose (control beverage) in alternate arms. Participants spitted saliva-beverage mixture immediately after, every each 15s intervals up to 1min, then after every 30s up to 2min and finally after3, 4 and 5min. pH of such collected samples was measured with a calomel pH microelectrode.
Results: Repeated measures for two-way ANOVA showed significant interaction among beverages and time (p<0.001). According to Tukey’s test salivary pH was significantly reduced over 2 min by the intake of orange juice and cola-type soft drink but pH recovery was significantly slower for the former.
Conclusions: Depending on the beverage, saliva buffering capacity may be less efficient and, therefore, longer is the time during which saliva remains acid.