Fluoride Concentration in Saliva following Professional Topical Application of 2% Sodium Fluoride Solution

BACKGROUND: Topical fluoride application in moderate and high-risk individuals and in those living in low-fluoride communities has been a common practice by dental professionals. OBJECTIVES: The objective of this study was to assess fluoride concentration available in saliva after a professional 2% sodium fluoride solution application (9000 ppm), and the duration of its availability to have an evidence-based practice for application. MATERIALS AND METHODS: Two percent sodium fluoride application was carried out in 45 participants residing in a boarding school. The participants were non tea drinkers and nonfluoride users. Water fluoride of the area ranged from 0.34 ppm to 0.38 ppm. Whole mixed saliva samples were collected at baseline and various time intervals postapplication of 2% sodium fluoride solution. Fluoride in saliva was estimated using the fluoride combination electrode (Orion model 94–09, 96–09) coupled to an ionanalyzer. RESULTS: IBM SPSS statistics version 23.0 was used for the analysis. Normality of the data was assessed using the Kolmogorov–Smirnov test and box plot, and it was found to be nonnormal. Wilcoxon signed-rank test was used to compare all time intervals with baseline, and statistically significant differences were observed (P = 0.0001). Salivary fluoride according to this study showed a biphasic clearance pattern with a peak at 15 min and a rapid fall in 60 min followed by a slow, consistent decline over a 20-h period. The fluoride concentration in saliva remained elevated above baseline from 0.03 ppm to 0.076 ppm even 3 months after application. CONCLUSION: Findings of this study show that, in this population, the frequency of application should be between 2 and 3 months (four applications per year).