A comparison of shear bond strength of brackets bonded to zirconia

Purpose: The objective of this study was to compare the shear bond strength (SBS) of ceramic orthodontic brackets bonded to highly translucent zirconia surfaces following the use of two different primers. Materials and methods: Three types of highly translucent zirconia crowns, Cercon xt ML, e.max ZirCAD, and STML-ML Katana Zirconia, were milled, sandblasted, and primed using two zirconia primers, Monobond Etch and Prime and Z-Prime Plus. A ceramic bracket (Radiance) was bonded onto the facial surface of each crown. Shear bond strength was evaluated using a universal testing machine. Results: There was no significant overall difference across the six experimental groups regarding shear bond strength. The use of the two tested zirconia primers resulted in comparable and clinically acceptable shear bond strengths. Conclusions: Both tested zirconia primers were associated with adequate bond strength when bonding a ceramic orthodontic bracket to the three highly translucent zirconia substrates.