2011 Volume 3 Issue 1 Pages 32-39
Purpose: To evaluate the shear bond strength and bonding durability of different self-adhesive resin cements to dental zirconia.
Method: The following self-adhesive resin cements were used in this study: G-luting, SA luting, RelyX Unicem and Smartcem. The specimens of zirconia were embedded into acrylic resin. Each specimen was then cemented in bonding area that was regulated with plastic tape (3.0 mm in diameter) using self-adhesive resin cement (self-curing mode) with a stainless steel rod (10 mm in diameter), after it was prepared using wet 600-grits silicone carbide paper. Each self-adhesive resin cement was prepared for each of the 14 specimens. Prior to performing the shear bond strength test, all bonded specimens (n = 14) were stored at 37°C -100% relative humidity for 1 hour and stored in 37°C distilled water for 23 hours. Half the specimens (n = 7) were repeatedly thermal cycled for 5000 cycles between 5 °C and 55°C. The shear bond strength of self-adhesive resin cement to zirconia was measured in a universal testing machine.
Results: The mean shear bond strength of the self-adhesive resin cements to zirconia varied from 7.5 to 66.1 MPa after storage in 37°C distilled water for 23 hours, and from 0.8 to 71.0 MPa after repeated thermal cycling. The shear bond strengths of the self-adhesive resin cements containing phosphoric acid ester monomer were slightly higher than for those containing carboxyl acid monomer. Observation of fracture mode determined that fractures did not occur at the interface with the stainless steel rods. All fractures occurred either at the interface between the zirconia surface and the cement (adhesive mode) or within the cement (cohesive mode).
Conclusion: Self-adhesive resin cements containing adhesive monomers such as phosphoric acid ester monomer showed slightly less accelerative degradation than other cements when bonded to dental zirconia.
