Background: With increasing demand for metal-free restorations, yttria-stabilized tetragonal zirconia polycrystal has become a preferred material for ceramic crowns, bridges, and other restorative dental procedures. Mechanical and laser treatments, including diamond bur grinding and laser irradiation can improve bond strength to zirconia, although there are controversies regarding their effectiveness.
Purpose: We aimed to evaluate the effects of three different surface treatment types, mechanical (diamond bur grinding), laser, and combined treatments, on the shear bond strength and surface roughness of zirconia.
Materials and Method: In this in vitro study, sixty yttria-stabilized tetragonal zirconia polycrystal specimens were prepared and divided into six groups, including a control group (standard polishing), as well as groups undergoing diamond bur, and/or laser irradiation. Specimens were treated with silane and bonded with composite resin before testing. Surface roughness was assessed using a profilometer. Bond strength was tested using a universal testing machine.
Results: The highest bond strength was observed in the diamond bur group (354.30 MPa), while the lowest was in the control group (159.50 MPa) (p Value< 0.001). Surface roughness also varied significantly among groups, with the diamond bur group showing the highest roughness values. Bur-laser-treated groups showed increased roughness compared to laser-only treatments.
Conclusion: This study found that combining mechanical and laser treatments significantly improved the shear bond strength and surface roughness of zirconia compared to control and laser-only groups. Such combinations may improve the longevity of zirconia restorations. Future research should explore long-term durability and optimize treatment parameters.