Method: In a crossover short-term in situ study of 6 steps, the anticaries potential of 2% sodium fluoride (NaF) gel (DFL®, 0.9% F), acidulated phosphate fluoride (APF) gel (DFL®, 1.23% F), APF foam (Laclede®, 1.23% F), F varnish (Duraphat®, 2.25% F) and bifluoride varnish (Duofluorid XII®, FGM, 6% NaF + 6% CaF2; 5.6% F) was evaluated. Applications, following clinical recommendations, were made extra-orally on bovine enamel blocks. The treated blocks were further kept in daily-renewed artificial saliva for 7 days, to simulate intraoral exposure and their baseline surface hardness (SH) was determined. Blocks of each treatment and controls not treated were mounted in palatal appliances in contact with a test plaque of S. mutans. The appliances were placed into the mouth of 12 volunteers and after 30 min 20% sucrose solution was rinsed simulating a cariogenic challenge. After 45 min the enamel blocks were collected, SH was again determined and the % of loss (%SHL) was calculated as indicator of demineralization. Also, CaF2-like products (“CaF2”) retained in enamel after saliva washing was determined in additional blocks.
Result: The highest (p<0.05) “CaF2” concentration (µg F/cm2) was observed in varnishes-treated enamel and the lowest in the control group, but among the other groups no difference (p>0.05) was observed. All products reduced enamel demineralization, compared with the control (%SHL=19.3±10.4). No difference was observed in %SHL among NaF-gel, APF-gel and APF-foam (12.9±9.6, 14.7±7.1, 14.9±8.9, respectively), but the lowest demineralization was found for the F-varnish and bifluoride-varnish (4.3±8.4 and 2.6±7.5, respectively).
Conclusion: The findings suggest that all professional F products tested present anticaries potential but those able to retain greater amount of “CaF2” on enamel after salivary exposure may be more effective. FAPESP 2008/01727-3.