Adhesion to eroded dentin submitted to different surface treatments

Resumo

Objective: This in vitro study measured the microshear bond strength (µSBS) of a composite resin to sound and artificially eroded dentin, submitted to surface treatment with diamond bur (DB) or Er,Cr:YSGG laser (L). Material and Methods: Bovine dentin samples were randomly divided into six groups (n=11): G1-sound dentin, G2-eroded dentin, G3-eroded dentin treated with Er,Cr:YSGG laser at 1.5W, G4-eroded dentin treated with Er,Cr:YSGG laser at 2.0W, G5-eroded dentin treated with Er,Cr:YSGG laser at 2.5W and G6-eroded dentin treated with diamond bur. Erosive cycling was performed by immersion in 0.05M citric acid (pH2.3;10min; 6x/day) and in remineralizing solution (pH7.0, 1h, between acid attacks), for 5 days. Three composite resin cylinders were bonded to the samples and after 24h storage in distilled/deionized water (37^oC), samples were submitted to microshear bond strength test and mean values (MPa) were analyzed by one-way ANOVA and Tukey tests (?=0.05). Results: G1 (19.9±7.6) presented the highest µSBS mean followed by G6 (12.2±3.8), which showed no statistically significant difference compared with the other groups, except from G4. The lowest µSBS value was found for G4 (7.1±1.5), which did not differ statistically from G2 (7.5±1.8), G3 (8.4±1.8) and G5 (8.6±3.2). Analysis of the fracture pattern revealed a higher incidence of adhesive fractures for all experimental groups. Conclusion: The results indicate that Er,Cr:YSGG laser at the parameters used in this in vitro study  did not enhance composite resin bonding to eroded dentin.