RESUMO
OBJECTIVES: The aim of this study was to evaluate the clinical performance of silorane-based composite restorations applied after different surface treatments. MATERIALS AND METHODS: This controlled and randomized clinical trial included 26 patients with class I restoration indications. The teeth were randomly assigned to the following treatments: control 1/G1, silorane specific self-etching adhesive (P90 self-etch primer and bond) + silorane-based composite resin (Filtek™ P90 low shrink posterior restorative); G2, 37% phosphoric acid + silorane specific self-etching adhesive + silorane-based composite resin; G3, blasting with aluminum oxide + silorane specific self-etching adhesive + silorane-based composite resin; and control 2/G4, self-etching adhesive (Adper™ SE Plus self-etch adhesive) + dimethacrylate-based composite resin (Filtek™ P60 posterior restorative). The clinical performance was evaluated at baseline and after 1 year. RESULTS: A total of 141 restorations were made and evaluated. For all clinical criteria evaluated, no significant difference was found between the surface treatments at baseline and after 1 year (p > 0.05). After 1 year, only the group with 37% phosphoric acid + silorane specific self-etching adhesive (G2) showed a significant reduction in marginal adaptation (p < 0.05). CONCLUSION: In general, all surface treatments showed an adequate clinical performance for silorane-based composite resin in class I restorations. However, a reduction in the marginal adaptation after 1 year was found when additional phosphoric acid etching was used prior to silorane specific self-etching adhesive. CLINICAL RELEVANCE: The use of phosphoric acid etching prior to specific self-etching adhesive can adversely affect the marginal adaptation of silorane-based restorations.