Effect of different adhesive systems and silane application on shear bond strength of resin cement to indirect restorations

Objective: This study compared the influence of various adhesive systems and silane application on the adhesion of resin-based luting cement to lithium disilicate, indirect composite resin, and zirconia restorations. Methods: Lithium disilicate (n=50), indirect composite resin (n=50), and zirconia (n=50) blocks were divided into five groups (n=10), according to the adhesive protocol applied as follows: 1. Optibond XTR, 2. silane + Optibond All in One, 3. One Coat 7 Universal, 4) Adper Scotchbond Multi-Purpose, and 5) Silane + Single Bond Universal. The blocks were bonded to a resin-based luting cement after surface treatments (silica coating and acid application). The bonded specimens were incubated in 37° C water for 24 hours and thermocycled for 5,000 cycles. The shear bond strength (SBS) was evaluated by a universal testing machine. The adhesion protocols for each type of restoration were compared by one-way ANOVA and Dunnett T3 test. Results: There were significant differences in the bond strength of cement to indirect restorations between various adhesive protocols (P 0.05). In all types of restorations, the highest SBS was observed in group 5, which was silanized and bonded with Single Bond Universal. The bond strength of group 5 in lithium disilicate, indirect composite resin, and zirconia groups were 26.1 ± 4.9 MPa, 20.5 ± 5.7 MPa, and 15.4 ± 4.7 MPa, respectively. Conclusions: It appears that the best adhesive protocol for bonding cement to lithium disilicate, indirect composite resin, and zirconia restorations is the use of silane and a universal adhesive containing silane (Single Bond Universal).