| Objective: The purpose of this study was to compare, in vitro, the cariostatic ability of different level of NaF solution by monitoring the process of demineralization of enamel surrounding orthodontic bracket.Material and Method: Brackets were bonded to 30 extracted sound first premolar with traditional composite resin and randomly assigned to five equal groups of six.. Group 1-4 was immersed in NaF solution with 2%, 1.5%, 1% and 0.5% F respectively for 1 hour after bonding; Group 5 served as the control with no topical application after bonding. All groups were cycled in an artificial caries challenge for 1 hour two times daily and an artificial saliva solution for 11 hours daily for 15 days. Changes of enamel was evaluated using a laser fluorescence system after bonding and at 3, 6, 9, 12 and 15 days of demineralization. ANOVA (P≤.0001) and Student-Newman-Keul (P≤.05)test indicated significant differences in fluorescence value.Result: (1)The fluorescence values of sound enamel had not signficant difference after bonding (P≤.0098) and rised by day 3, the control group's was higher than other groups' (α≤.05); 2% group's value was lower than other groups' by day 6 (α≤.05); 0.5% group's was higher than 1% and 1.5% groups' by day 9 (α≤.05); There had no significant deference between 1% and 1.5% groups'. (2)Value changes became significant at day 12 in 2% group, day 9 in 1% and 1.5% groups, day 6 in 0.5 group and day 3 in control group (α≤.05).Conclusion: High lever fluoride could not inhibit the enamel demineralization in acid environment absolutely, but could slow down the rates of decay and reduce the extent. The cariostatic ability of NAF became more intensify in higher lever. |
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