Does caries-removal method affect the dentin bond strength of high-viscosity glass ionomer cements?

Aim: The objective of this study was to evaluate the impact of manual and rotary instruments on the microtensile bond strength of high-viscosity glass ionomer cements (GICs) to caries-affected dentin. Methods: Twelve sound molars and 24 molars with dentin caries were sectioned perpendicular to the long axis at the mid-dentin region. Teeth were divided into six groups (n=6) according to the carious tissue removal method (E: excavator, B: rounded bur), and restorative material (EQ: Equia® Forte Fil, RIV: Riva Self-Cure). The control group was formed by sound teeth (S: sound) restored with both materials. After a 24-hour storage in distilled water at 37°C, the teeth were sectioned along the long axis to obtain 1 mm thick slices and the adhesive interface was reduced to 1.2 mm with a diamond bur. The specimens were subjected to microtensile bond strength tests at a 1.0 mm/min crosshead speed in a universal testing machine. Data were submitted to two-way ANOVA, followed by the Games-Howell test with a significance level of 5%. Results: No significant differences were found for caries removal technique and restorative material (p˃0.05), but the interaction between these variables was statistically significant (p<0.05). The EQ-S and RIV-E groups showed significantly higher microtensile bond strength than the other groups (p<0.05), except for the RIV-B, which exhibited no significant difference when compared to all the other groups (p>0.05). Conclusion: The caries removal method did not negatively affect the dentin bond strength of Riva Self-Cure, while Equia® Forte had higher bond strength to sound dentin.