Effect of nonfluoridated milk and fluoridated milk on acidic dental plaque

Purpose: Recovering the acidic plaque pH to its resting value as soon as possible after exposure to a sugary beverage might reduce the risk of dental caries. Milk contains nutrients that help to buffer acid. Adding fluoride to milk might enhance this effect. Accordingly, this study investigates the effect of milk and fluoridated milk on acidic dental plaque. Methods: The study was a randomized crossover design. Ten subjects were asked to rinse for 2 min with the following solutions: (1) water, (2) 10% sucrose, (3) milk, (4) fluoridated milk, (5) 10% sucrose followed by water, (6) 10% sucrose followed by milk, or (7) 10% sucrose followed by fluoridated milk. The supra-gingival plaque was collected before rinsing and every 5 min after rinsing to measure the plaque pH. Results: The results showed that rinsing with 10% sucrose caused acidic dental plaque. After rinsing with 10% sucrose followed by milk, fluoridated milk, or water, the maximum plaque pH dropped and the area under the curve was significantly less than that after rinsing with 10% sucrose alone (p = 0.001). The maximum change in the plaque pH and the area under the curve in the group challenged with 10% sucrose followed by fluoridated milk were significantly lower than those in the group followed by nonfluoridated milk (p = 0.04). Conclusion: Rinsing with milk could raise the acidic plaque pH to the resting value faster than individual's natural capacity to do so. Adding fluoride to milk can enhance this effect.