Effect of Different Surface Treatments on Bond Strength of Zirconia-Veneer

Delamination of veneering porcelain in zirconia-based  restorations is the most common clinical problem. The purpose of this study was to investigate shear bond strength (SBS) between various surface treatment applied zirconia and veneering ceramic with two different application  methods  and  effect of liner material to SBS.

Method:

One hundred sixty (15x12x1.6mm³) zirconia discs (IPS e-max ZirCAD) were prepared. Samples were divided into 4 groups according to the surface treatment (n=40); control, sandblasting, sandblasting+acid, grinding. Liner was applied to half of these samples (n=20). Subgroups were divided into 2 groups; veneered (5 mm in diameter, 3 mm in thickness) with layering and pressing veneer (n=10). All specimens were subjected to thermal cycling; tested in a universal testing machine with a cross head speed of 0,5mm/min; fractured surface specimens were evaluated with stereomicroscope and SEM, surface roughness of zirconia were evaluated in SEM and AFM. Data were statistically analyzed (α=0.05).

Result:

SBS values of pressing methods were 21,064,48; SBS of layering methods were 17,055,04.  SBS of groups with liner had 17,114,73, SBS of groups without liner had 20,954,86. Grinding group had the highest bonding strength (24,065,79) and control group had the lowest (13,474,41), but there were no a significant difference between the groups.

Conclusion:

According to this study; pressing method has higher SBS value than layering. Liner dramatically reduced SBS between zirconia and veneer ceramic in all groups. Different surface treatments didn’t affect on SBS between zirconia and veneering.