Permeabilidade dentinária e morfologia da interface adesiva de diferentes sistemas adesivos

Objective: Compare dentine permeability of different adhesive systems with and without hydrophobic resin. Analyze the influence of pulpal pressure on the morphology of the adhesive interface. Methods: For the permeability assay, teeth were randomly allocated in 4 groups (n = 9), according to the adhesive systems: Futurabond U (Voco) self-etch; Futurabond U etch-and-rinse; Scotchbond 1. XT (3M-Espe); Easybond (3M-Espe) with subsequent application of an hydrophobic resin [Adhesive; Scotchbond Multipurpose system (3M-Espe)]. Hydraulic conductance of each specimen was measured on a permeability apparatus. To characterize the morphology of the adhesive interface in scanning electron microscope, 3 specimens from each group subjected to pulpal pressure were used, and new specimens (n = 3) were prepared without pulpal pressure, according to the same adhesive system, forming the 4 groups described before. Permeability of the different adhesive systems was compared with Anova and Tukey post-hoc (p < 0.05). Permeability before and after the hydrophobic resin layer was compared with a paired t student test for repeated measures. Results: Permeability was significantly lower with Futurabond U self-etch when compared to the etch-and-rinse groups (p < 0.05), both before and after hydrophobic resin layer application. Hydrophobic resin layer lead to a significant reduction on the permeability for all adhesive systems (p < 0.05). Hybrid layer was not identified on the self-etch groups as opposed to the etch-and-rinse groups. Adhesive interface had alterations when the pulpal pressure was applied. Conclusion: Hydrophobic resin layer reduced the permeability in all adhesive systems tested. Structural defects were present in all groups when the adhesive procedures were performed under pulpal pressure.