Purpose This study evaluated the shear bond strength (SBS) of a metal bracket bonded to three different computer-aided
design/computer-aided manufacturing (CAD/CAM) restoration materials pretreated with different surface treatments. In
addition, the surface topography and color change of the restorations after debonding with two different tungsten carbide
burs were examined.
Methods A total of 216 plates were cut from three different CAD/CAM blocks, each of which was divided into three
subgroups with different pretreatment methods: (1) acid etching, (2) sandblasting, and (3) laser irradiation. Incisor metal
brackets were bonded. The SBS test was performed, and the failure types were classified. Then, samples were randomly
divided into two subgroups according to the adhesive removal procedure to be used: a tungsten carbide bur with 12 blades
or 24 blades (n= 12). Color change was calculated based on the E00, and surface morphology was evaluated via SEM
and AFM analysis.
Results The SBS data revealed that the type of CAD/CAM material and the applied surface treatment significantly
affected bond strength. The highest SBS values were detected for the Grandio Blocs (VOCO GmbH, Cuxhaven, Germany;
14.3± 4.4MPa), and the lowest was observed for Cerasmart (GC Europe, Leuven, Belgium; 12.0± 4.0MPa). The E00
results demonstrated significant differences only as a result of the applied surface treatment. The E00 value in all groups
was above the 1.77 threshold.
Conclusion CAD/CAM material types and surface treatments affected the bond strength, but the interactions of these
factors did not. The chosen surface treatment also significantly affected the E00 after the polishing was done.