effect of air abrasion and erbium-doped yttrium aluminum garnet (er: yag) laser preparation on shear bond strength of composite to dentin

introduction: the aim of this study was to assess shear bond strength of composite to dentin after air abrasion and laser treatment. methods: 40 human extracted molars divided into 4 groups (n=10) received the following treatments. group 1: carbide bur, group 2: air abrasion with aluminum oxide 50 μm, group 3: irradiated with erbium-doped yttrium aluminum garnet (er: yag) laser (150 mj/20hz), group 4: irradiated with er:yag laser (150 mj/20hz)+ air. specimens in all groups were chemically etched with phosphoric acid 37% and treated with bonding agent (single bond 3m). then, composite build-up was performed by tygon tube. after storage in distilled water at 37°c for one week, all specimens were subjected to a shear bond strength test with universal testing machine. data were analyzed with anova and t-test. results: the mean and standard deviation of shear bond strength of the 4 groups were 20.8±6.76, 14.98±3.98, 11.43±4.36 and 14.95± 3.18 mpa, respectively. conclusion: air abrasion after laser treatment improved the shear bond strength.