Fluorine concentration in primary tooth enamel in 6-year-olds after 3 years of daily intake of fluoride-containing tablets (Fludent).

The purpose of this study was to determine the posteruptive uptake of fluorine in primary tooth enamel after daily consumption of a fluoride-containing sucking tablet for three years. The material consisted of 17 children, who had been advised to suck on 1 NaF tablet (Fludent, 0.25 mg F) daily at bedtime from 3 to 6 years of age (test group), and 17 children without tablet supply (control group). No other fluoride preparation was used during the period. A chemical biopsy method, described by Koch et al. (1982), was used to determine the fluorine concentration in enamel at the age of 6. Two consecutive layers on the upper central primary incisors of each child were etched off by perchloric acid. Chemical analysis of the test solutions was used to determine the thickness of the enamel layers and the fluorine content. Statistical evaluations were performed by analysis-of-variance. The results showed that fluorine was incorporated in primary tooth enamel as a topical effect of the fluoride tablet intake. There was a statistically significant difference (p less than 0.05) between the groups regarding fluorine measured on the layers combined and in the out layer (approximately equal to 5 micron thick), but not in the inner layer (approximately equal to 8 micron). It was concluded that the posteruptively increased enamel fluorine concentration probably contributes to the caries-preventive effect of NaF tablets.