The effects of XeCl laser etching of Ni–Cr alloy on bond strengths to composite resin: a comparison with sandblasting procedures

Objectives The aim of this study was to determine the effect of laser surface treatment of Ni–Cr alloy on the tensile bond strength of a proprietary composite resin (Panavia 21) in comparison with a conventional sandblasting technique. Methods Eighty cylinders of Ni–Cr were randomly allocated into the following groups: Group I—sandblasting only; Group II—low laser fluence (3.0 J/cm2); Group III—medium laser fluence (4.0 J/cm2); Group IV—high laser fluence (4.9 J/cm2); Group V—sandblasting in combination with medium laser fluence (4.0 J/cm2). Specimens within groups were bonded into pairs with resin cement as per manufacturerʹs instructions. They were then de-bonded using a tensile test. Results The mean de-bond strengths (SD) were: Group I—13.1 (4.2) MPa; Group II—17.6 (5.8) MPa; Group III—25.7 (11.8) MPa; Group IV—22.6 (6.6) MPa; Group V—41.8 (13.2) MPa. A statistically significant improvement (Bonferroni, p<0.05) in bond strength was found for the specimens which had been both lased and sandblasted (Group V) compared to all other groups, including those which were only sandblasted. Significance Laser pre-treatment of Ni–Cr alloy increases bond strength to composite resin compared with sandblasting; laser pre-treatment in combination with sandblasting further increases the de-bond strengths.