Avaliação da permeabilidade dentinária de sistemas adesivos experimentais contendo vidros bioativos

Abstract

Introduction: Adhesion of restorative materials to dentin is a highly sensitive procedure, as it is an intrinsically hydrated and permeable tissue. The hydrolytic degradation of the adhesive layer interferes with the durability of the resin-dentin bond, with a significant decrease in the bond strength of dentin to the adhesive system over time. There are indications that the inclusion of bioactive glass particles in the adhesive system can be an effective agent against dentin permeability. Bioactive glasses are materials capable of inducing the release of fluorine and calcium ions, which have shown an inhibitory effect on the enzymatic activity of matrix metalloproteinases (MMPs), proteolytic enzymes that induce the degradation of dentinal collagen in the hybrid layers, in addition to obstructing the dentinal tubules due to the formation of mineral precipitates. So the association of adhesive systems and bioactive glasses can result in the reduction of the dentinal fluid flow and help in the adhesion of hydrophobic materials. Objective: To evaluate the dentin permeability of four experimental adhesive systems incorporated with bioactive glass 45S5 at 10% and 20%, and NbG at 10% and 20%, compared to an experimental adhesive without bioglass. Method: Two-step self etching adhesive systems containing 10 and 20% by weight of 45S5 and NbG bioactive glasses were tested on forty freshly extracted human teeth. An experimental adhesive without microparticles was used as a control group. Dentin permeability was evaluated immediately after application of the adhesive system and 30 days after storage in PBS. For statistical analysis, data were submitted to Shapiro-Wilk, One-way ANOVA and Holm-Sidak tests. The statistical significance level was set at 5%. Results: Significant differences were observed in the reduction in the hydraulic conductance (Lp) value between the adhesive systems evaluated after 30 days immersed in PBS (p ≤ 0.001). Conclusion: The addition of bioactive glass 45S5 and NbG at concentrations of 10% and 20% to an experimental adhesive system decreased the dentin permeability of the specimens evaluated after 30 days immersed in PBS when compared to the same adhesive system without the addition of bioactive material.