Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 12 4 2015 10 12 281 289 EN Soghra Yassaei 1Associate Professor, Department of Orthodontics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Hossein Agha-Aghili Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Abdolrahim Davari Associate Professor, Department of Operative Dentistry, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Seyed Morteza Saadat Mostafavi Postgraduate Student, Department of Orthodontics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran 2015 10 12 2015 10 12 Objectives: Providing reliable attachment between bracket base and zirconia surface is a prerequisite for exertion of orthodontic force. The purpose of the present study was to eval- uate the effect of four zirconium surface treatment methods on shear bond strength (SBS) of orthodontic brackets. Materials and Methods: One block of zirconium was trimmed into four zirconium sur- faces, which served as our four study groups and each had 18 metal brackets bonded to them. Once the glazed layer was removed, the first group was etched with 9.6% hydrofluoric acid (HF), and the other three groups were prepared by means of sandblasting and 1 W, and 2 W Er: YAG laser, respectively. After application of silane, central incisor brackets were bonded to the zirconium surfaces. The SBS values were measured by a Dartec testing ma- chine with a crosshead speed of 1 mm/min. Results: The highest SBS was achieved in the sandblasted group (7.81±1.02 MPa) followed in a descending order by 2 W laser group (6.95±0.87 MPa), 1 W laser group (6.87±0.92MPa) and HF acid etched group (5.84±0.78 MPa). The differences between the study groups, were statistically significant except between the laser groups (P < 0.05). Conclusion: In terms of higher bond strength and safety, sandblasting and Er: YAG laser irradiation with power output of 1 W and 2 W can be considered more appropriate alterna- tives to HF acid etching for zirconium surface treatment prior to bracket bonding. https://fid.tums.ac.ir/index.php/fid/article/view/300 https://fid.tums.ac.ir/index.php/fid/article/download/300/282