Effect of various types of milk on salivary pH among children: a pilot randomized controlled crossover trial.

Objective: This study aimed to evaluate salivary pH changes after consuming three types of milk in children aged 3-5 years. The null hypothesis was that no statistically significant difference would be noted in the salivary pH between high-protein, full-fat, and sweetened milk groups at different time points.

Materials and methods: This was a double-blind, pilot randomized controlled crossover trial. 30 Children have undergone three experimental sessions with a 1-week washout period. Each child was given 250 mL of one of the following types of milk: high-protein, full-fat, or sweetened milk. The salivary pH was measured at the baseline (t₀) after 5 (t₁), 10 (t₂), 15 (t₃), 30 (t₄), and 60 (t₅) minutes of milk consumption, using a pH saliva indicator strip.

Results: There is a sharp drop in salivary pH after 5 min of sweetened (P < 0.05) and full-fat milk consumption (p < 0.05). However, the initial drop in the salivary pH was found to remain above the critical level. For the high-protein milk group, salivary pH decreased slightly after 5 min but was similar to that at the baseline (p = 0.573). In the high-protein milk group (p < 0.05), the salivary pH was slightly greater than the baseline value at t₅.

Conclusions: The study shows an initial suggestion that milk is a non-cariogenic beverage, even when sugar is added. Furthermore, high-protein milk has a protective effect from dental caries.