Effect of different surface treatments on the shear and microtensile bond strength of resin-modified glass ionomer cement to dentin

OBJECTIVE: The aim of this study was to evaluate the effect of different surface treatments on the microtensile bond strength (μTBS) and shear bond strength (SBS) of resin-modified glass ionomer cement (RMGIC) to dentin. MATERIALS AND METHODS: Fifty-two extracted human molars were flattened to obtain dentin surfaces. For SBS assessment 40 teeth were divided into four groups according to their surface treatments (acid etching, Er:YAG laser QSP mode, Er:YAG laser MSP mode and control-SiC) (n = 10). A plastic cylinder was placed over the differently treated dentin surfaces and RMGIC was placed into the rings and polymerized. Twelve teeth were used for the μTBS test. The treated dentin surfaces described above were restored with 4 mm high RMGIC and light cured; then, the specimens were sectioned into serial sticks (n = 15) and μTBS and SBS were tested for failure in a testing machine with a 1 mm/min crosshead speed. The data were analyzed by one-way ANOVA and Tukey HSD tests (α = 0.05). RESULTS: Acid etching showed significantly higher SBS than the other groups (p < 0.05). Er:YAG QSP and MSP-treated groups showed higher SBS values than the control group, but the difference was not statistically significant (p > 0.05). Er:YAG MSP showed the highest μTBS value followed by acid etching, whereas the control group exhibited the lowest value (p < 0.05) and the differences between the control group and Er:YAG QSP were not significant (p > 0.05). CONCLUSIONS: The application of Er:YAG MSP mode and acid etching to dentin can be used for improving the bond strength of RMGIC.