The objective of this study was to evaluate the effect of sonic application of universal adhesives on the enamel microshear bond strengths (µSBS), in situ degree of conversion (DC) and etching pattern. Ninety-six extracted third molars were sectioned in four parts (buccal, lingual, proximal) and divided into 12 groups, according to the combination of 1) adhesive system (All-Bond Universal [ABU], G-Bond Plus [GBP], Prime&Bond Elect (PBE), and Scotchbond Universal Adhesive [SBU]), and 2) adhesive application mode (manual active etch-and-rinse [M-ER], manual active self-etch [M-SE], and sonic vibration self-etch [S-SE]). Specimens were stored in water at 37 °C during 24 h and tested at 1.0 mm/min (µSBS). DC was evaluated in the enamel-resin interfaces using micro-Raman spectroscopy. The enamel-etching pattern was evaluated under a field- emission scanning electron microscope. Data were analyzed with two-way ANOVA and Tukey's test (α = 0.05). S-SE application increased µSBS and DC for all universal adhesives when compared to M-SE (p < 0.05). S-SE application resulted in mean bond strengths that were statistically similar to those obtained with the respective ER application mode (p > 0.05). A deeper enamel-etching pattern was observed for all universal adhesives in the etch-and-rinse strategy. An improvement in etching ability was observed in S-SE application compared to M-SE application. In light of the improved performance of universal adhesives when applied sonically in SE mode, selective enamel etching with phosphoric acid may not be crucial for their adhesion to enamel. The sonic application of universal adhesives in self-etch mode may be a practical alternative to enamel etching.
Bibliographical noteFunding Information:
This study was partially supported by in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil ( CAPES ) - Finance Code 001 and National Council for Scientific and Technological Development ( CNPq ) under grants 304104/2013-9 and 305588/2014-1 .
© 2018 Elsevier Ltd
- Degree of conversion
- Microshear bond strength
- Sonic application
- Universal adhesive systems