Efeito de tratamentos de superfície da resina, cimento resinoso e envelhecimento nas características interfaciais de restaurações semidiretas de resina composta

Abstract

The semi-direct technique performed with composite resin can be an excellent treatment option for deep and extensive restorations on posterior teeth due to technical difficulties in the use of composite resin by the direct technique, as well as the higher cost and time of treatment of indirect restorations with porcelain. The aim of the study was to evaluate the effect of different treatments of the restoration surface, types of resin cement for cementation and aging times on the bond durability to dentin, failure pattern and nanoleakage of semi-direct restorations. 320 bovine incisors were used (N = 320), from which discs of 4.0 mm thickness were obtained and, in its most central portion, a conical cavity preparation with 4.8 mm in diameter and 2.8 mm in diameter was made. The samples were divided into 16 groups according to the resin cement: RelyX Ultimate (ULT) e RelyX U200 (U200); resin surface treatment: Silane (S), Single Bond Universal (SBU) and S+SBU; and aging time: 24 hours (24h) and 6 months (6m). The analyzes performed were: Bond Strength to push-out extrusion (BS), Failure Pattern (FP) and Nanoleakage (NL). The data were analyzed using descriptive and inferential statistics using ANOVA Three Way with Tukey's Post Hoc (p <0.005). For BS, ULT showed better performance in both times of aging. SBU showed better results after 6m when associated with ULT. The averages increased with time for U200, except when silane was used as a surface treatment. In the analysis of the FP, the ULT presented the highest percentage of mixed failure, when the fracture occurred simultaneously in dentin or restored material and at the adhesive interface, at both times of aging and when it was used in association with SBU or S + SBU as treatment resin surface. The different surface treatments and aging times did not influence nanoleakage at the cement-resin interface. According to the results found in this laboratory study, a better performance was observed for the ULT and among the surface treatments, the use of SBU enabled greater BS, however it did not influence the nanoleakage at the cement-resin interface. It is suggested that semi-direct composite resin restorations can be cemented with ULT with SBU as a resin surface treatment, as well as with U200, without the need for any chemical treatment in the restoration.