RESUMO
OBJECTIVES: To determine the impact of treating caries-affected dentin (CAD) with: 0.2% sodium fluoride (NaF), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP/MI Paste™) or peptide P11-4 (Curodont™ Repair) on the longevity of resin/CAD interface at storage times of 24 -h, 6- and 18-month. METHODS: 255 caries-free third molars were used, and CAD was produced by a biological method. The teeth were randomly distributed into: G1- Sound dentin (SD); G2- CAD; G3- CAD + 0.2% NaF (CAD/NaF); G4- CAD + CPP-ACP (CAD/ACP); G5- CAD + Curodont™ Repair (CAD/P11-4). The Filtek Z350 composite resin block was bonded to dentin using Adper™ Single 2 (4 mm/height). Resin/dentin blocks were stored in a solution of Simulated Body Fluid at 37 °C, pressures were modified to simulate natural pulpal pressures. Specimens were investigated by microtensile bond strength (µTBS) (n = 8), Scanning Electron Microscopy (to assess the failure mode) (n = 8), nanoinfiltration (to assess the interface sealing) (n = 3), in situ zymography (to assess the gelatinolytic activity) (n = 3) and micro-computed microtomography (µ-CT) (to assess the mineralization) (n = 3). Data from µTBS, µ-CT and, nanoinfiltration and hybrid layer formation/degradation were submitted to two-way ANOVA and Tukey tests, and failure patterns and in situ zymography to Kruskal-Wallis and Dunn tests (α = 5%). RESULTS: The highest mineral density change by µ-CT, smallest silver nitrate infiltration and proteolytic activity in the adhesive layer were obtained significantly for the groups SD, CAD/ACP and CAD/P11-4, with most mixed fractures at 18-month (p < 0.001). CAD/NaF showed significantly similar values to CAD, CAD and CAD/NaF which presented a high percentage of adhesive fracture (p < 0.001) at all time periods. SIGNIFICANCE: Treating caries-affected dentin with remineralizing agents CPP-ACP and Curodont™ Repair, has the potential to be a clinically relevant treatment protocol to increase the longevity of adhesive restorations.
