Resistência ao cisalhamento e padrão de condicionamento de sistemas adesivos autocondicionantes em esmalte intacto e preparado / Shear bond strength and etching pattern of self-etching bonding agents on ground and intact enamel

ABSTRACT

Objective: The aim of this study was to evaluate the shear bond strength of four self-etching adhesive systems on intact and ground enamel, and also to evaluate the morphology of the enamel surface after etching.Methods: A total of 100 bovine central lower incisors were randomly divided into five groups: Single Bond (3M ESPE, St. Paul, USA), Adper Prompt L Pop (3M ESPE, St. Paul, USA), Clearfil SE Bond (Kuraray America, USA), One-up Bond F (Tokuyama Corp., Shibuya-ku, Tokyo, Japan) and AdheSE (Ivoclar/Vivadent, Schaan, Liechtenstein). Each group was subdivided (n=10), according to the surface preparation (intact or ground enamel). For intact enamel, the teeth were pumiced and ground enamel surfaces were obtained with wet 320-grit SiC paper. A circular (4mm) bonding area was demarcated and resin rods (Filtek Z250, 3M ESPE, St. Paul, USA) were built (5mm) for the shear test, followed by failure mode analysis using Scanning Electron Microscopy. In addition, 12 teeth were prepared for the evaluation of the etching pattern by Scanning Electron Microscopy. Statistical analysis of the data was performed with two-way ANOVA and Tukey?s test (p<0.05). Results: Significant differences were observed between the Shear bond strength values for the adhesive systems (p<0.001). No differences were found between the two substrates (p=0.598) nor any interaction between the adhesive systems versus substrate (p=0.404). The etching patterns were generally observed as mild when compared to phosphoric acid, except for Adper Prompt L Pop (3M ESPE, St. Paul, USA), which was similar to phosphoric acid. Conclusion: Shear bond strength was not influenced by the type of substrate (intact or ground enamel), and no correlation was observed between the Shear bond strength values and the etching pattern of the self-etching adhesives studied.