Effect of Various Post-Brushing Activities on Salivary Fluoride Concentration after Toothbrushing with a Sodium Fluoride Dentifrice

The study consisted of eight experiments, divided into three series, aimed at investigating the effect on the salivary fluoride (F) concentration of three post-brushing regimes: (1) rinsing once or twice with water, (2) rinsing either with a slurry of the toothpaste foam and water or with an 0.05% NaF solution, or a single NaF mouthrinse with no prior brushing, and (3) chewing and drinking (‘eating’) for 2 min. Brushing was done with 1.5 g of an 0.32% NaF dentifrice. The concentration of F in whole saliva was determined in 15 subjects at various time points up to 45 min after completing each experimental procedure. Results showed that the initial (0 min post-brushing) F concentration in saliva decreased about 1-2 times after a single, and 4-5 times after a double post-brushing water-rinse, as compared with no rinsing at all (p < 0.001). Brushing followed by a mouthrinse with an 0.05% NaF solution elevated the F concentration more than brushing alone (p < 0.001). Rinsing with the slurry of toothpaste foam and water gave only a somewhat (but not significantly) lower concentration of F in saliva than just rinsing with the 0.05 % NaF solution. Eating immediatly after brushing reduced the salivary F level about 12-15 times (p < 0.001) compared with brushing alone. The conclusions from this study are therefore: (1) that both rinsing with water and eating immediately after toothbrushing accelerates the rate of F elimination in saliva, and (2) that mouthrinsing either with an 0.05% NaF solution or with the toothpaste foam-water slurry after brushing elevates the concentration of F in saliva for a prolonged period of time as compared with toothbrushing followed by a single or a double water-rinse.