Fluoride Concentrations in Plaque, Whole Saliva, and Ductal Saliva After Application of Home-use Topical Fluorides

Abstract

It is now well-accepted that the primary anti-caries activity of fluoride (F) is via topical action. The retention of F in the mouth after topical fluoride treatment is considered to be an important factor in the clinical efficacy of F. The purpose of this study was to evaluate F levels in ductal saliva, whole saliva, and pooled plaque after treatment with topical F agents intended for home use. Ten consenting adults, mean (SD) age 31.0 (8.2) years, participated in all aspects of the study. Two days before each test, subjects received a professional tooth cleaning and subsequently abstained from all oral hygiene procedures to permit plaque to accumulate, and from the use of F-containing dental products. Treatments consisted of a placebo dentifrice (PD), fluoride dentifrice (FD; 0.24% NaF), fluoride rinse (FR; 0.05% NaF), and fluoride gel (FG; 1.1% NaF). Unstimulated whole saliva and pooled plaque were sampled at multiple points over a 24-hour period. In a separate experimental series, stimulated parotid saliva was sampled over a two-hour period after treatment. Fluoride levels generally followed the same pattern in whole saliva and pooled plaque samples, with FG > FR > FD > PD. Night-time F application resulted in prolonged F retention in whole saliva but not in plaque. Fluoride levels in parotid saliva were only slightly higher after F treatment and returned to baseline levels within two h. The results of this study indicate that the method of F delivery, the F concentration of the agent, and the time of application (daytime vs. night-time) are important factors influencing F levels in the mouth. The recycling of F in ductal saliva as a consequence of the inadvertent ingestion of home-use fluoride products does not appear to make a clinically significant contribution to F levels in the mouth.