Tratamentos de superfície para reparo em restaurações de resina composta

Abstract

The aim of this study was to evaluate in vitro the performance of surface treatments of composite resins used to improve the repair ability of restorations. The study was developed in three stages: (1) systematic review of the literature on laboratory studies that compared different types of surface treatments used to enhance the repair bond strengths; (2) evaluation of the effect of diamond burs granulometry of used for abrasion of composites before the repair; (3) preparation and evaluation of experimental primers containing various concentrations of acidic monomer, silane, polyacrylic acid or methacrylic acid to enhance the repair potential of composite restorations. In stage 1, the search was conducted in three international databases, and included articles that assessed the repair bond strength of composite submitted to different surface treatments (control: untreated composite). In total 15 articles were included, the bond strength data extracted and subjected to meta-analysis using random effects model. Data showed that the application of chemical or physical + chemical surface treatments improve the repair bond strengths. In stage 2, fresh or aged composites were treated with medium, fina (F) or extra-fine (FF) diamond burs. The best repair ability was observed when the fine diamond bur was used, while aging did not affect significantly the composite repair ability, particularly due to the rougher aspect of aged composite. In stage 3, divided into two articles, the composites were treated using experimental primers and the repair bond strengths were characterized. Application of primers improved the bond strengths compared to the control groups (no composite treatment), being the best combination of formulation observed for the presence of up to 10 wt% acidic monomer, silane, polyacrylic and methacrylic acids. Analyzing the three stages of this study, it can be concluded that application of physical surface treatments (such as fine-grit diamond bur), chemical surface treatments (such as resin-based primers) and combination of physical + chemical treatments might positively influence the bond strength of dental methacrylate-based composite restoratives. The use of surface treatments prior to composite repair should, thus, be encouraged in clinical practice.