الفهرس 
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Abstract
Purpose: The purpose of this in-vitro study was to evaluate the shear bond strength (SBS) of pressable ceramic bonded to four different core materials.Methods: Sixty-four cylinders of IPS e-max Press were fabricated. Four core materials were prepared (n=16), and three of them were fabricated according to manufacturer recommendations as disc-shaped specimens of (IPS e-max ZIRCAD), Composite resin (Te-Econom Plus), and resin-modified glass ionomer (RMGIC) (GC FUJI II LC Capsule) and the fourth one was human dentin. Human dentin was prepared by embedding sixteen molars in acrylic resin, and then their occlusal surfaces were grounded to flat dentin. Each core group was divided into two subgroups (n=8) according to cement type, either multistep-adhesive resin cement (Multilink® N, Ivoclar Vivadent) or self-adhesive resin cement (Breeze, Pentron Clinical Technologies). Ceramic cylinders were bonded to core materials. All bonded specimens were stored in a water bath for five months at 37oC, then thermocycled in hot and cold water between (5-55o) for 5000 cycles. SBS test was performed using a universal testing machine at 0.5 mm/min. A stereomicroscope was used to determine the failure mode, followed by SEM examination. Data were analyzed using Two-way ANOVA, One-way ANOVAs at each level of study, and Tukey’s HSD test at (p=0.05).
Results: There were statistically significant differences between test groups, with the highest mean SBS for composite resin groups followed by RMGI groups and lowest mean SBS for dentin groups followed by zirconia groups with no significant difference regarding cement type.
Conclusion: Different core materials affect the SBS of pressable ceramic, while the cement type has no effect.