The aim of this study was to evaluate the effect of three adhesive systems with and without silane application on feldspathic porcelain/resin composite bond strength. Three adhesive systems [Adper Scotchbond Multipurpose (SM), Adper Single Bond 2 (SB), Single Bond Universal (SU)] and one silane coupling agent [RelyX Ceramic Primer (Silane)] were used in this study. Sixty feldspathic porcelain disks 6 mm in diameter, 4 mm in thickness were prepared and embedded in dental gypsum. Specimens were polished with 400 and 600 grit silicon carbide paper, respectively. The samples were randomly divided into six groups (N=10 for each group) according to different treatments applied on feldspathic porcelain surfaces: Group1 (Silane-SM), Group2 (SM), Group3 (Silane-SB), Group4 (SB), Group5 (Silane-SU) and Group6 (SU). A silicone template (3 mm diameter, 2 mm thick) was placed on top of treated feldspathic porcelain surface. The resin composite was filled into the mold and then lightirradiated by light curing unit at a light intensity of 1000 mW/cm2 for 40 seconds. All bonded specimens were kept in distilled water at 37oC for 24 hours and they were subjected to shear bond strength
measurement using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were statistically analyzed using one-way ANOVA and Tukey’s test (α=0.05). The shear bond strengths (MPa) of Group1 to Group 6 were 23.41±4.16, 12.66±0.91, 20.92±4.03, 10.80±1.43, 32.00±1.87, and 12.01±1.18 MPa, respectively. The shear bond strengths of Group1, Group3, and Group5 were significantly higher than those of Group2, Group4, and Group6 (p<0.05). Furthermore, Group5 showed the highest shear bond strength and was significantly higher than those of Group1 and Group3 (p<0.05).
In conclusion, the silane had a positive effect on shear bond strength between feldspathic porcelain and resin composite when used with the three adhesive systems. Silane application followed by adhesive application increased shear bond strength for all systems.