Comparison of shear bond strength of orthodontics brackets on composite resin restorations with different surface treatments.

Introduction: Orthodontic patients frequently present composite resin restorations, however there are few studies that evaluate the best way for orthodontic bonding in this situation.

Objective: The objective of this work was to evaluate the bond strength of orthodontic brackets in resin restorations with surface treatment.

Methods: Fifty one bovine lower incisors were randomly divided into three groups. On the control group (CG) the brackets were bonded to dental enamel; on experimental groups, brackets were bonded to resin restoration with diamond drill treatment (EGT) and with no treatment (EGN). The teeth were placed in PVC tubes with self-etching acrylic resin. The shear test was performed in EMIC universal testing machine. The groups were submitted to ANOVA analysis of variance with Tukey post test to verify the statistical difference between groups (α = 0.05).

Results: CG (6.62 MPa) and EGT (6.82 MPa) groups presented similar results, while EGN (5.07 MPa) obtained statistically lower results (p < 0.05).

Conclusions: Therefore, it is concluded that the best technique for bonding orthodontic brackets on composite resin restorations is the performance of surface detritions.