Shear bond strengths of various luting cements to zirconia ceramic: surface chemical aspects.

OBJECTIVES

To measure the shear bond strengths of various luting cements to a sandblasted zirconia ceramic and to determine the surface energy parameters of the luting cements.

METHODS

Two conventional glass ionomer cements, two resin-modified glass ionomer cements, two compomer cements, and two adhesive resin cements were prepared and bonded to sandblasted zirconia (Lava). All bonded specimens were stored in water at 37°C for 48 h and then half of them additionally thermocycled 10,000 times prior to the shear bond strength test (n=10). Surface roughness (R(a)) values and surface energy parameters of the eight luting cements and polished zirconia ceramic were evaluated using a profilometer and contact angle measurements, respectively (n=10). The bond strength and surface roughness data were statistically analysed using non-parametric and parametric procedures, respectively (α=0.05). Relationships between surface energy parameters and measured shear bond strengths were investigated using the Spearman rank correlation test.

RESULTS

Panavia F 2.0 and Principle produced higher bond strengths than the other cements, with no significant changes before and after thermocycling. Fuji I, Ketac Cem Easymix, and Ionotite F yielded near-zero or zero values after thermocycling. All debonded specimens showed adhesive failure. Mean R(a) values ranged from 0.104 to 0.167 μm. We found the base (hydrogen bond accepting) components of the luting cements significantly affected the bond strengths both before and after thermocycling.

CONCLUSION

It is recommended that the surface energy parameters of luting cements be considered in evaluating their adhesive properties with zirconia ceramic.