Comparative evaluation of effect of One Coat 7 Universal and Tetric N-Bond Universal adhesives on shear bond strength at resin–zirconia interface: An in vitro study

BACKGROUND: Success of all-ceramic restorations depends on their cementation process. Bonding crystalline materials like zirconia to an underlying substrate is challenging. Recently, universal adhesives have been developed. They claim to chemically bond to zirconia due to the presence of compounds like 10-methacryloyloxydecyl dihydrogen phosphate. But for majority of these adhesives, few studies demonstrating their effectiveness are available. AIMS: This study aimed to assess the effect of two universal adhesives, One Coat 7 Universal and Tetric N-Bond Universal on shear bond strength at zirconia–resin junction. MATERIALS AND METHODS: Thirty CAD-CAM milled zirconia cylinders (5 mm × 8 mm) were sandblasted and divided into three groups: Group A (control) received no treatment, while Groups B and C were primed by One Coat 7 Universal and Tetric N-Bond Universal, respectively. They were luted to composite surfaces by a dual-curing resin cement. After 24 h, a shear bond strength test was conducted and failure mode was analyzed. STATISTICAL ANALYSIS: One-way analysis of variance and post hoc Tukey's test were used for statistical analysis. RESULTS: Both One Coat 7 Universal (24.43 ± 2.66 MPa) and Tetric N-Bond Universal (28.61 ± 3.11 MPa) had significantly higher strength than the control group (9.86 ± 2.00 MPa). Control group underwent 100% adhesive failures. Experimental groups had predominantly mixed/cohesive failures. CONCLUSION: Both universal adhesives increased the bond strength at resin–zirconia junction. Tetric N-Bond Universal exhibited the highest strength.