Oral Fluoride Bioavailability by the Consumption of Meals Prepared With Fluoridated Water or Salt

This study will assess the concentration of fluoride in saliva and dental biofilm (fluid and solids) during and up to 2 hours after the consumption of typical Brazilian meals prepared with fluoridated water (0.7 ppm F) or fluoridated salt (250 mg F/kg). Typical Brazilian meals (rice, beans, meat with vegetables) will be prepared using fluoridated water, salt, or non-fluoridated water and salt. In an crossover design, twelve volunteers will eat 4.67 g of food/kg body weight of each meal, on fasting, during 15 min. Before the ingestion, unstimulated saliva and dental biofilm will be collected for determination of fluoride concentration. During the meal, 3 samples of the alimentary bolus (at 5, 10 and 15 min of mastication) will be collected for determination of fluoride concentration. Dental biofilm will be collected immediately after the ingestion of the meal. Saliva will then be collected after 5, 10, 15, 30, 60 and 120 min. All samples will be analyzed for fluoride using an ion-specific electrode. In order to standardize biofilm formation, during lead-in and wash-out periods, volunteers will: 1. brush their teeth with non-fluoride toothpaste; 2. refrain from brushing superior posterior teeth for 2 days before each phase; and 3. chew sucrose-containing chewing gum 5 times/day, for 10 min, during the 2 days prior to each phase. Groups will be compared by ANOVA and Tukey test.