comparison of the effect of nd:yag laser and sandblasting on shear bond strength of a commercial ni-cr alloy to porcelain

introduction: failures might occur at metal‒porcelain interfaces as a problem with metal‒ceramic restorations even with the application of airborne-particle abrasion technique. this study was undertaken to evaluate the effect of nd:yag laser treatment on the bond strength of porcelain fused to metal. methods:  twenty-four cylindrical specimens (4 mm in diameter and 4 mm in height) were made of a commercially available nickel‒chromium alloy by lost-wax technique. half of the specimens were surface-treated by air-borne particles and the other half was irradiated with nd:yag laser beams (wavelength of 1064 nm, energy and frequency of 120 mj and 10 hz, respectively, and a power setting of 6 kw). all the specimens (air-abraded and laser-treated) were covered with a 4-mm layer of opaque porcelain in two-stage baking and subjected to shear bond strength test (a 10-kgf at 1 mm/min) until fracture occurred. a fractured specimen from each group was evaluated using scanning electron microscopy. t-test was used for statistical analysis and statistical significance was set at p< 0.05. results: shear bond strength was higher in the sandblasted group compared to the laser-etched group (p< 0.05). conclusion: it can be concluded that nd:yag laser irradiation increases the shear bond strength of ni-cr alloy to porcelain, but further studies should be carried out to evaluate the effect of different parameters of nd:yag laser treatment on shear bond strength.