Method: APF-gel (1.23% F, pH 3.5) or NF-gel (0.9% F) was applied on bovine enamel blocks. Untreated blocks were used as control. Half of the blocks were immersed in artificial saliva for 7 days to simulate the dissolution of CaF2-like products that occurs in vivo. In a double-blind, crossover, short-term in situ design, 12 participating volunteers wore palatal appliances containing freshly-treated or exposed to saliva blocks, kept in contact with a S. mutans test plaque and acid challenged by a sucrose rinse. After 45 min, mineral loss was evaluated by change in blocks surface hardness and calcium and phosphate release to test plaque fluid.
Result: Although higher (p<0.05) alkali-soluble F (CaF2-like) concentration (µg F/cm2) was formed on the APF-gel treated blocks (42.3±24.0) in comparison to the NF-gel (7.1±4.6), they did not differ in terms of F retained after exposure to saliva (1.7±0.7 and 1.4±0.7, respectively) (p>0.05), with significantly lower values in the control group (0.3±0.1) (p<0.05). CaF2-like products formed and retained on enamel by both gels were able to reduce mineral loss when compared to the control (p<0.05). Although a higher effect of the freshly applied APF-gel was observed when compared to the NF-gel (p<0.05), no difference between them after exposure to saliva was seen (p>0.05).
Conclusion: The results suggest that the high concentration of CaF2-like products formed on enamel immediately after application should not be used to estimate the anticaries potential of professionally-applied fluoride. FAPESP 2008/01727-3
Keywords: Biofilm, Caries, Enamel, Fluoride and Plaque
See more of: Cariology Research - Fluoride and Ca-based Products