Abstract:
BACKGROUND : Variolink II is the only resin cement used for bonding IPS (Ivoclar
Porcelain System) Empress 2 ceramic restorations. Alternative luting resin
cements need to be investigated for their bonding effectiveness with the IPS
Empress 2 ceramic. OBJECTIVES : To determine the shear bond strength (SBS) and
the effect of thermocycling, on the bonding effectiveness, of five resin cements to
IPS Empress 2 ceramic. MATERIALS AND METHODS : The projecting surfaces of one
hundred ceramic discs were ground wet on silicone carbide paper. The specimens
were divided into 5 groups of 20. The resin cements were bonded to the prepared
ceramic surfaces, in the form of a stub. The specimens were stored under distilled
water at 37°C in an oven for 24 hours. Ten specimens in each group were
thermocycled for 300 cycles between 5°C and 55°C. All the specimens were
stressed to failure in an Instron Materials Testing Machine. RESULTS : The results
were subjected to a one-way analysis of variance (ANOVA). Statistically similar
mean SBS values were grouped using the Bonferroni (Dunn) multiple comparison test. The means for the non-thermocycled group were: 26.21, 19.41, 17.69, 17.43,
and 15.76. The means for the thermocycled group were: 22.90, 15.72, 14.34,
13.96 and 13.45. The differences between the means were highly significant
(p< 0.0125). CONCLUSIONS : The shear bond strength of Variolink II and Rely X
ARC to IPS Empress 2 ceramic was effective. Thermocycling had a significant
effect on the mean SBS values of Calibra. Thermocycling had no significant effect
on the mean SBS values of the other resin cements.
