The Effect of Combining Zirconia Primer with Different Adhesives on the Shear Bond Strength of Brackets Bonded to Zirconia Restorations

ABSTRACT Objective: To compare the shear bond strength (SBS) of orthodontic brackets using three types of adhesives, with and without the application of a zirconia primer. Material and Methods: A total of 144 glazed zirconia discs were prepared and randomly assigned to two groups. The first group was sandblasted, while the second group was roughened with a burr. Half of the discs in each group were treated with Zirconia Primer (Z Prime Plus), and the other half were not. The discs were then divided into three subgroups: Scotchbond Universal bonding (SBU) was used as the adhesive for the first subgroup, All Bond Universal bonding (ABU) for the second, and Transbond XT (TX) for the third to bond stainless steel brackets to the zirconia discs. TX composite was then used to bond the metal brackets to the discs. The discs were subjected to thermocycling, and both the SBS and the ARI index were measured. Results: In the bur roughening groups, the use of Z Prime Plus did not have a significant effect on the SBS of SBU and TX adhesives, but it significantly increased the SBS of the ABU adhesive. When comparing adhesives within the bur roughening groups, the SBS of TX was significantly lower than that of ABU and SBU adhesives, while there was no significant difference between ABU and SBU. In the sandblast group, there was no significant difference in SBS between the three adhesives. Comparing the two surface preparation methods, the SBS was higher with sandblasting than with bur roughening. Conclusion: The use of a zirconia primer increased the shear bond strength of the All Bond Universal adhesive. However, this increase was not significant for the other two adhesives tested.