Comparative study of the shear bond strength of the resin/bracket interface, using three different resin composites and three different treatments in the base of the bracket

Adriano Lia MONDELLI, Marcos Roberto de FEITAS

Aim: Considering that the adhesion between the brackets and the resin is chemo-mechanical, the aim of this study was to investigate: 1) the efficacy of the method used to assess the bond strength at the resin/bracket interface; 2) the shear bond strength of the resin/bracket interface using three resin composites (Concise orthodontic, Transbond XT and Filtek Z-250); 3) the effect of sandblasting of the base of the metallic bracket with aluminum oxide, associated or not to the application of adhesive. Methods: Shear bond strength was carried out at a universal testing machine. Data were submitted to analysis of variance and Tukey multiple comparison test. Results and Conclusions: The occurrence of 12.5% of cohesive failures may be considered minimal, thus indicating that the method is appropriate to assess the bond strength at the resin/bracket interface. The different resin composites (Concise Orthodontic, Transbond XT and Filtek Z-250) used for bonding without any previous surface treatment of the bracket (control groups) resulted in similar shear bond strength. The application of adhesive, with or without previous sandblasting of the base of the bracket, improved the shear bond strength for the Concise orthodontic resin composite, when compared to its control group. Sandblasting of the bracket, regardless of the combined use of adhesive, was statistically superior for the Transbond XT resin composite when compared to its control group. The application of the adhesive Single Bond in the base of the bracket, with or without previous sandblasting, promoted a decrease in the shear bond strength for the Filtek Z-250 resin composite. Sandblasting of the metallic bracket with aluminum oxide improved the adhesion at the resin/bracket interface for all the resin composites used in this study.

Keywords: Shear bond strength. Resin composites. Bonding.

Saturday, December 28, 2024 23:08