Influence of hydrophobic layer of Bis-EMA with different ethoxilations on adhesive's bonding efficacy and mechanical properties

The aim of this study was to evaluate the effects of a hydrophobic layer of Bis-EMA 4 (B4, 4 ethoxilations), Bis-EMA 10 (B10, 10 ethoxilations) or Bis-EMA 30 (B30, 30 ethoxilations) on dentin adhesion and mechanical properties of a universal adhesive. Extracted human molars were cut and restored using self-etching mode of Ambar Universal (AU, FGM) adhesive and divided according to the hydrophobic layer employed (n = 8): only AU (Control), SBMP (Scotchbond Multi-Purpose adhesive, 3 M, Commercial Control), B4, B10 and B30. Microtensile bond strength (μTBS) and nanoleakage tests were performed after 24h and 6 months water storage. Interface micro-permeability was surveyed by confocal microscopy. Dynamic-mechanical analysis (DMA) of each adhesive combination (50 wt% Ambar + 50 wt% BisEMA or 100% Ambar) were assessed. The data were statistically analyzed using two-way ANOVA and Tukey's test (p