Variation of Salivary pH After Sweet and Oat Biscuit Intake-A Crossover Randomized Controlled Trial

To assess salivary pH variation after consumption of two types of biscuits, i.e., cocoa biscuits with a sweet-creamy filling (Oreo original) and oat biscuits (Digestino oat).

A crossover randomized trial was conducted on a convenience sample of young adults with permanent dentition, whose diet included biscuits. Salivary pH was registered by pH strips, before and after biscuit intake, and then at 5 min intervals, over a period of 30 min.

Salivary pH had a similar pattern of variation for both biscuits used, but differences were noted, respectively, the range and maximum drop being slightly larger for Oreo original; timing of pH beginning to increase from maximum drop being delayed for Oreo original compared to Digestino oat, approximately 20 vs. 15 min after intake; the pH drop compared to baseline was not statistically significantly different at any timepoints for Digestino oat, but pH was statistically significantly lower starting from 15 to 25 min after intake for Oreo original. pH recovery at thirty minutes was frequent (69% of the participants) for Digestino oat, but it was rare (20% of the participants) for Oreo original. After the Oreo original intake, mouth rinsing with water enabled pH recovery (afterward in 60% of participants). Minimum salivary pH was strongly correlated to the initial pH for Oreo original intake (r = 0.780; p < 0.001), but moderately correlated for Digestino oat intake (r = 0.445; p < 0.012).

Results suggest salivary pH registers similarities of the general pattern of variation after biscuit intake, but cocoa biscuits with sweet filling, compared to oat biscuits, seem to have a higher acidogenic effect.