Avaliação da resistência ao cisalhamento de braquetes colados com resinas ortodônticas fluoretadas

Abstract

The aim of this study was to evaluate the shear bond strength of brackets bonded with fluoride-releasing composite resins, and to compare them to a conventional resin. For this study, sixty premolars extracted due to orthodontic reasons were used, which were divided into three groups: Group 1- Concise (3M), Group 2- Ultrabond (Aditek do Brasil) and Group 3- Rely-a-bond (Reliance). All bonded specimens were stored in distilled water at 37°C for 24 hours and termocycled between 5°C and 55°C for 500 cycles. After 48 hours, the specimens were submitted to the shear bond strength test, in occluso-gingival direction, in Material Test System MTS 810 machine, with load speed of 0.5 mm/min. Variance Analysis, Levene Test, Shapiro-Wilk Test and Tukey Test were used for data analysis. The results demonstrated a mean shear bond strength of 24.54 ± 6.98 MPa for the Concise; 11.53 ± 6.20 MPa for the Ultrabond; and of 16.46 ± 5.72 MPa for the Rely-a-Bond. Variance Analysis determined a statistical difference amongst groups (p<0.001). Tukey Test evidenced that the averages of the three groups were significantly different among themselves (p<0.05), with the highest resistance for the Concise Group and the lowest for the Ultrabond Group. However, all the materials presented bond strengths, which were suitable for clinical use.