The aim of this project will be to evaluate the effects of water exposure on the microtensile bond strength, on the nanoleakage patterns and on the ultramorphological characteristics of resin-dentin interfaces produced by different self-adhesive resin-based cements. Five self-adhesive cements will be used: RelyX Unicem (3M Espe), Breeze (Pentron), BisCem (Bisco), G-Cem (GC America), Maxcem (Kerr); and two conventional resin cements (Rely X ARC, 3M Espe; and Panavia F, Kuraray). Eighty-four third molars will be used, which will be randomly distributed into 7 groups according to the luting material, and then subdivided into 3 subgroups according to water exposure method: 24 hours, 12 months with a circumferential enamel margin and 12 months with dentin margins. Pre-polymerized composite cylinders will be cemented according to manufacturers’ instructions. After the storage periods, the restored teeth (n=4) will be serially sectioned, producing beams with a cross-sectional area of 0.8 mm2 at the resin-dentin interface, which will be tested in tension in a universal testing machine. Teeth luted with each material will be submitted to a nanoleakage protocol with AgNO3 after each storage period (n=4) and will be prepared for observation in a Scanning and Transmission Electron Microscope. Two additional specimens in each group will be prepared for ultrastructural observation of the resin-dentin interface with the TEM for the determination of the interaction mechanism between these materials and dentin. The bond strength and nanoleakage data will be statistically analyzed by two-way ANOVA and Tukey test.
News published in Agência FAPESP Newsletter about the scholarship: