The Effect of Surface Treatment on Hardness and Shear Bond Strength between Ceramic and 3-Yttrium Zirconia

Background: The veneer chipping from zircon core is one of the elements driving ongoing research. Two types of 3Y zirconia is mostly used as a core in both anterior and posterior region according to their indications, covered by veneering ceramics and need strong bond force.Aim: To reveal effects of the surface treatments on the shear bond strength and hardness of 3Y zirconia to veneering porcelain. Materials and methods : 80 zirconia samples were used in this study , 40 samples of (Dentaldirekt DD Z ) 3Y high-alumina zirconium core, another 40 samples were made of (Dentaldirekt DD ZX ) ,3Y low-alumina. Each type were subdivided into two groups: 20 micro-rods (5*25*1.5 mm) in size were created for hardness test , 5 samples for each type of surface treatments(5 samples laser, 5 samples acid etching ,5 samples for sandblasting and 5 samples as a control group). The other subgroup zirconia specimens (diameter of 7 mm\ height: 3 mm) for shear bond strength test, 5 for each type of surface treatments. 6W Er;Cr:YSGG as a laser surface treatment was used and 9.5 % Hydrofluric acid was used as acid etching. 120 μm alumina used for sandblasting.Results: Hardness test was showed no statistical difference between surface treatments groups and control group. While shear bond strength test was showed that laser and acid etching a rise in shear bond strength.Conclusion: Surface treatments did not affect the Hardness while laser and acid etching improve zirconia shear bond strength to veneering ceramic.