Effect of Surface Treatments on Bond Strength of All-Ceramic Cores

Objectives: The aim of this study was to evaluate the effects of various surface treatments on the shear bond strength between resin cement and ceramics. Methods: A total of 120 heat-pressed ceramic specimens were prepared to compare the effect of different surface treatments on the shear bond strength of a luting cement to two all-ceramic systems. IPS Empress 2 and IPS E.max Press ceramic specimens (10 x 10 x 2 mm) were fabricated according to the manufacturers' instructions. The ceramic blocks were divided into six groups that receive different surface treatments (control, sandblasting, sandblasting+etching, etching, laser (Nd:YAG), laser+etching) for both ceramic systems. Treated surfaces were inspected by scanning electron microscopy (SEM). To fabricate standardized composite resin cylinders, a polyethylene mold was used. Resin cement (Variolink II) was then bonded to the treated ceramic surfaces using a composite-filling instrument according to the manufacturer's instructions and then light polymerized. The specimens were subjected to thermocycling for 2000 cycles between 5 and 55 °C. The shear bond strengths (SBS) of the specimens were measured using a universal testing machine at a crosshead speed of 0,5 mm /min. Two-way ANOVA and Tukey HSD tests were performed to evaluate the data (a= 0.05). Results: The ANOVA revealed significant differences between the treatment groups and ceramics. IPS Empress 2 ceramics showed significantly higher SBS values than IPS E.max Press ceramics. In both ceramic groups, control group showed significantly lower SBS value, and sandblasting+etching group showed the highest SBS value than the other groups. Conclusions: Surface treatment procedures affected bonding a resin cement to ceramic. IPS Empress 2 was showed significantly higher SBS values than IPS E.max Press. Sandblasting+etching surface treatment provided the highest bonding between the resin and ceramics tested.