Micro-shear bond strength of different resin cements to ceramic/glass-polymer CAD-CAM block materials

Abstract

Purpose: The aim of this study was to evaluate the effects of hydrofluoric acid treatment on bond strength of resin cements to three different types of ceramic/glass containing CADCAM block composite materials. Methods: CAD-CAM block materials of polymer infiltrated (Vita Enamic), resin nanoceramic (Lava Ultimate) and nanoceramic (Cerasmart) with a thickness of 1.5 mm were randomly divided into two groups according to the surface treatment performed. In Group 1, specimens were wet-ground with silicon carbide abrasive papers up to no. 1000. In Group 2, 9.6% hydrofluoric acid gel was applied to ceramics. Three different resin cements (RelyX,Variolink Esthetic and G-CEM LinkAce) were applied to the tubes in 1.2-mm thick increments and light-cured for 40 s using LED light curing unit. Half of the specimens (n = 10) were submitted to thermal cycling (5000 cycles, 5-55 8C). The strength measurements were accomplished with a universal testing machine (Lloyd Instruments) at a cross-head speed of 0.5 mm/min until the failure occurs. Failure modes were examined using a stereomicroscope and scanning electron microscope. The data were analyzed with multivariate analysis of variance (MANOVA) and Tukey's post hoc tests (a = 0.05). Results: There were significant differences between ceramics and resin cements ( p < 0.001). However, hydrofluoric acid gel treatment had no effect on bond strength values ( p = 0.073). In addition, thermal cycling significantly decreased bond strength values of resin cements to ceramics ( p < 0.001). Conclusions: Use of appropriate resin cement systems with different ceramic/glass-polymer materials might promote the bonding capacity of these systems.