In vivo enamel fluoride uptake after use of fluoride products

To evaluate fluoride uptake in enamel after use of products containing different fluoride components of distinct oral hygiene regimen in vivo.

84 healthy subjects (24 females and 60 males aged 19-26 years, mean 22.2) recruited from the students attending the courses of the Medical Faculty of the University of Sassari, Italy, were randomly assigned to one of four treatments groups: A: treated with a dentifrice containing sodium monofluorophosphate (1250 ppm F-); B: treated with dentifrice with 1250 ppm F- from AmF; C: treated with an AmF toothpaste (1250 ppm F-) and a mouth rinse with 250 ppm F- from AmF; or D: treated with a NaMFP toothpaste (1250 ppm F-) plus 1250 ppm NaMFP varnish. Acid-etched enamel microbiopsies on the vestibular surface of the first maxillary premolar were collected at baseline (to), after 20 days of test product use (t1) and after 24 hours without treatment (t2). Fluoride concentration was measured using an ion-specific electrode. All measurements were made in triplicate and analyzed statistically using two-way factorial ANOVA for independent samples standard weighted-means analysis.

The fluoride uptake in the enamel shows a considerable variation between the groups. Significant differences were found both within all products in terms of fluoride concentration in enamel for (P < 0.0001 for two-way ANOVA, and later Tukey HSD test). After 20 days of treatment, the group using AmF toothpaste plus AmF mouthrinse had a higher fluoride uptake than the groups using either of the other products (P < 0.05). In conclusion, all products lead to an appreciable amount of fluoride uptake in enamel; AmF products led to higher concentrations. The concentration of fluoride accumulated during treatment phase remained high after 24 hours following the cessation of use.