Influence of surface treatments on bond strength of resin cement to CAD/CAM ceramics

Abstract

The aim of this study was to investigate the bond strength of a resin cement (RelyX Veneer, 3M Oral Care) to feldspathic (Cerec Blocs, Dentsply Sirona) and leucite-reinforced (IPS Empress CAD, Ivoclar Vivadent) CAD/CAM ceramics submitted to different surface treatments: G1, 5% hydrofluoric acid (HF) application for 20s; G2, 5% HF application for 60s; G3, 10% HF application for 20s; G4, 10% HF application for 60s; G5, Monobond Etch and Prime (Ivoclar Vivadent) (MEP) application for 20s; G6, MEP application for 60s. For groups G1, G2, G3 and G4 a silane was applied for 1 min after HF treatment. Resin cement cylinders were adhered to the treated surface and shear bond strength (SBS) test was performed, after 24-h immersion in distilled water at 37oC, using a universal testing machine (EZ-Test, Shimadzu). SBS data were analyzed by one-way ANOVA followed by Tukey’s post hoc test (?=0.05). Fractured samples were analyzed with an optical microscope (KH 8700, Hirox) and were classified according to the failure: adhesive (ADE), cohesive in ceramic (COC), cohesive in resin cement (COR), mixed between adhesive and ceramic (MAC), mixed between adhesive and resin cement (MAR), mixed between adhesive, resin cement and ceramic (MARC). MEP showed higher bond strength for both ceramics. Application of 5% HF for 20s reduced the bond strength to feldspathic ceramic. The HF concentration (5% or 10%) did not influence the bond strength to leucite-reinforced ceramic.