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 (t(0)) after 5 (t(1)), 10 (t(2)), 15 (t(3)), 30 (t(4)), and 60 (t(5)) 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 t(5). 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.