The aim of this study will be to evaluate the influence of a hydrogen peroxide whitening mouthrinse containing fluoride on the remineralization potential of white spot lesions (WSL), assessed by reflectometry and transversal microradiography analysis. Additionally, the effect of the whitening treatments on the enamel fluoride uptake will be investigated. 120 bovine enamel/dentin specimens (6mm diameter and 3mm thickness) with WSL will be submitted to a 8-day remineralization cycling model, consisting of 2h immersions in demineralizing solution, 1min treatments with solutions (whitening mouthrinses, fluoride solution and placebo) and fluoride gel and 2h for bleaching gel, and 22h in remineralizing solution. The treatments will be performed before and after the immersion of the specimens in demineralizing solution. Ultrapure water will be used as the negative control. The treatment groups are: LWE (Listerine Whitening Extreme - 2.5% hydrogen peroxide and 100ppm sodium fluoride); OPF (Opalescence PF - 10% carbamide peroxide and 0.25% sodium fluoride); FS (Fluoride solution - 100 ppm sodium fluoride); PL (Placebo mouthrinse - 100ppm sodium fluoride); FG (Fluoride gel - 0.25% sodium fluoride); and DW (Deionized water - negative control). The initial Knoop microhardness will be used to randomize the samples into groups. For enamel surface reflection intensity evaluation, a scan of enamel surface will be performed on three different areas with the Optical Pen-Size reflectometer (OPSR) during treatment phases (before enamel demineralization (left side of enamel surface), on the enamel demineralization region (central and right exposed surface) and after treatments and remineralizing cycling (central area). Mineral loss and lesions depth will be evaluated with transversal microradiography method and aiming to quantify fluoride on enamel surface and subsurface, the KOH-insoluble fluoride measurement will be performed in additional specimens of each treatment (n=10). Data will be submitted to normality test and the proper statistical tests will be performed (±=5%).
News published in Agência FAPESP Newsletter about the scholarship: