Relationship between Caries and Fluoride Uptake by Enamel from Two Fluoride Varnishes in a Community with Fluoridated Water

The relationship between caries and fluoride uptake by enamel after five semiannual applications of Duraphat® and Fluor Protector® was studied in 51 and 60 children, respectively, aged 13–15 years and living in a community with fluoridated water. A weak inverse relation between initial enamel fluoride content and fluoride uptake was found. The fluoride uptake from both varnishes was higher in the more caries-active children, particularly when DMFS increment on occlusal surfaces was considered. Children with negative reversals on buccal or lingual surfaces had a higher final enamel fluoride level than those with no reversals. With Duraphat, a weak positive correlation between caries reduction and fluoride uptake was found (r = 0.29, p < 0.05), but not with Fluor Protector.