الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
Objectives: to compare in vitro the effect of three different types of fluoride gel (1.23% acidulated phosphate fluoride, 2.72 %
sodium fluoride and 0.4% stannous fluoride) on the remineralization of demineralized enamel surfaces.
Methods: Forty caries-free, human premolars without cracks or erosion, extracted for orthodontic purposes were collected.
Baseline surface microhardness analyses were done after all teeth were immersed in demineralizing solution for 72 hours. The teeth were divided into 4 groups with relative mean values of microhardness number for each group. The enamel surface
microhardness number was measured in each sample of the four groups by application of 4.9 N load for 10 seconds, using the microhardness tester. Another surface microhardness analysis was done after conducting a 10 days pH cycling model. Each
cycle involves four hours of demineralization followed by twenty hours of remineralization by immersion in remineralizing solution.
Results: ANOVA and Newman-Keuls post-hoc test show that there is a statistically non- significant values between reductions in Vickers hardness mean number in tested groups
Conclusion There was not a statistically significant difference between reductions in demineralization in tested groups.
Although there was not a statistically significant difference between tested groups (SnF) group had the lowest reduction in demineralization followed by the (NaF) and the (APF) gel group.
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