Amount of residual fluorine in the mouth and occurrence of unpleasant symptoms after the topical application of fluoride

Abstract

This study was undertaken to determine the amount of fluorine that remained in the mouth after the topical application of fluoride and to survey whether the topical application of fluoride induced any unpleasant symptoms by using a questionnaire. A total of 44 females aged 18 to 27 years, who attended a dental hygienist school in Sendai City, participated in this study. Using the double blind method, topical applications of both 2% NaF solution and placebo (normal saline solution) were made at an interval of 5 days. The subjects were instructed to apply 2ml of the solution and to use a cotton applicator according to a modified Muhler's technique. After the topical application was over, the residual solution, the cotton applicators and cotton rolls used for treatment and the saliva secreted during treatment were all collected individually. The fluorine content of these samples was determined with a fluorine-ion electrode. The mean amount of residual fluorine in the mouth was 1.83mg per person, ranging from 0.70-3.19mg, and 0.037mg per kilogram of body weight, ranging from 0.012-0.067mg.
Two days after the treatment, a questionnaire survey was also carried out and anyone who complained of any unpleasant symptoms was interviewed. There was no statistically significant difference between the two kinds of topical solution. When the mean amount of residual fluorine per kilogram of body weight was compared between the group complaining of unpleasant symptoms and the other, there was no significant difference but the latter showed a higher value than the former. The majority of those that complained of unpleasant symptoms referred to the strain and fatigue induced by the clinical practice.
From these findings, it was assumed that the occurrence of unpleasant symptoms was caused by the mental and physical stress involved with clinical practice rather than by acute fluoride poisoning by injestion.