Studies on the techniques of topical application with fluoride gel. III: Oral fluoride retention following three different topical application techniques in young adults.

Eighteen young adults volunteered to be subjects for topical fluoride gel application using the paint-on technique with cotton pellets and two tray techniques with improved sponge tray and a custom-fitted tray. The subjects' teeth were dried with compressed air, and the fluoride gel was applied topically for four minutes. The amounts of fluoride applied and/or recovered from the mouth were measured, and those retained in the mouth were also estimated for each technique. Furthermore, the amounts of excessive gel that were wiped off with a gauze and expectorated one minute after application were also evaluated, and these efforts were effective in reducing the amounts of oral fluoride retention. The net amounts of fluoride that were orally retained in each technique were very small (1.6 to 3.0 mg). It was found that the application techniques in the present study had no risks of causing some deleterious effects by applying excessively large amounts of fluoride.