The effect on dental enamel of varying concentrations of fluoridated milk with a cariogenic challenge in situ

摘要

Objectives: This study investigated the effect of two concentrations of fluoride in milk, 2.5 and 5.0 ppm, on the prevention of demineralisation with a cariogenic challenge compared with milk with 0 ppm F. Methods: In a controlled, randomised, cross-over, double-blind in situ study, 23 subjects wore a lower removable appliance with 2 enamel slabs for 21 days during each study arm. Subjects used F-free toothpaste and the cariogenic challenge comprised of five 2 min dippings per day in 12% sucrose. The slabs were dipped in 50 ml of milk with 0 ppm, 2.5 ppm or 5.0 ppm F twice daily for 5 min. Subjects drank 100 ml twice per day of the same milk. Slabs were analysed with Knoop microhardness to assess changes in mineralisation. Results: Results showed that enamel was softened in all groups but the extent of enamel softness was reduced with an increasing concentration of F in milk, being highly significant for both F groups compared to the control (p < 0.0001). 5.0 ppm F group showed a trend towards less softening compared to the 2.5 ppm F but was not statistically significant. Conclusions: In our in situ model, 2.5 and 5.0 ppm F in milk significantly protected enamel from demineralisation.