Shear bond strengths of two newly marketed self‐adhesive resin cements to different substrates: A light and scanning electron microscopy evaluation

Abstract The purpose of this in vitro study was to compare the shear bond strengths (SBSs) of two newly marketed self‐adhesive resin cements (RCs) to enamel, dentin, and lithium disilicate (LiSi) glass ceramic block. Forty‐eight enamel and 48 dentin substrates were obtained from sound human molars. Additionally, 6 × 7 × 5 ‐mm‐ sized 24 specimens were produced from LiSi glass ceramic blocks. The tooth specimens were randomly assigned into four groups ( n = 12) according to the surface treatments: (1) G‐CEM ONE (GCO), (2) G‐CEM ONE Adhesive Enhancing Primer (GCO‐AEP) + GCO, (3) RelyX Universal (RXU), and (4) Scotchbond Universal Plus (SUP) + RXU. LiSi specimens were randomly divided into two groups ( n = 12): (1) G‐MultiPrimer (GMP) + GCO and (2) SUP + RXU. Following the RC applications, all specimens were kept in 100% humidity at 37°C for 24 hr and then submitted for SBS testing in a universal testing machine (1 mm/min). Data were analyzed by Welch's, one‐way analysis of variance and two independent samples t tests. The nature of failures was examined under a light microscope, and scanning electron microscopy analyses were also performed for interfaces. GCO and RXU showed similar SBS to enamel ( p > .05), and the use of adhesives resulted in improved SBS ( p < .05). No difference was detected between GCO‐AEP + GCO and SUP + RXU. The GCO‐AEP + GCO exhibited the highest SBS to dentin ( p < .05), followed by GCO ≥ SUP + RXU > RXU ( p < .05). There was no significant difference between SBSs of two RCs to LiSi blocks ( p > .05). No cohesive failure was determined for the tested groups by light microscope. The use of adhesives prior to the application of self‐adhesive RCs improved their bonding to tooth tissues. GCO demonstrated superior SBS to dentin, whereas both self‐adhesive RCs generated similar SBS to enamel and LiSi glass ceramic surfaces.