The effect of fluoridated milk on human dental enamel in an in vitro demineralization model

Fifty-seven sound human permanent premolars were demineralized for 14 days and then exposed to six different treatments: group 1, 1 mg/1 fluoride in milk for 7 days; group 2, 1 mg/l fluoride in milk for 14 days; group 3, 10 mg/l fluoride in milk for 7 days; group 4, 10 mg/l fluoride in milk for 14 days; group 5, control non-fluoridated milk for 14 days, and group 6, control tap water for 14 days. Enamel etch samples were taken and analysed for fluoride and for phosphorus. An increase in the enamel surface fluoride content was observed in groups 1-3. A statistically significant elevation (p < 0.01) of fluoride content and a significant decrease (p > 0.001) of acid solubility were found only in group 4.