Effect of water rinsing after acidulated phosphate fluoride gel on dental plaque acidity: an in situ study.

Purpose: This study's purpose was to determine whether rinsing with water or cleansing teeth after topical fluoride therapy affected plaque acidity.

Methods: This randomized, controlled, crossover, in situ study was conducted on 25 dental students who wore an acrylic mandibular appliance containing one enamel block. The patients were subjected to four treatment protocols involving acidulated phosphate fluoride (APF) application followed by rinsing the mouth with water: (1) after 30 minutes (APF-30); (2) after 15 minutes (APF-15); (3) immediately (APF-0); after cleansing the teeth with a cotton roll immediately following APF (APF-cotton); or (4) no fluoride therapy (control). After 48 hours, plaque pH was measured before and five, 10, 15, 20, and 30 minutes after rinsing with 10 percent sucrose solution.

Results: The least pH changes, the lowest pH drop, and the fastest pH recovery were found in the APF-30 and APF-15 groups, followed by the APF-0 and APF-cotton groups.

Conclusions: Rinsing with water or cleansing the teeth with a cotton roll immediately after acidulated phosphate fluoride application can reduce its effect on dental plaque acidity; however, the inclusion of a controlled water rinse 15 minutes after APF gel application did not seem to influence the inhibitory effect of fluoride on plaque acidity.