Does acid etching prior to applying universal adhesives affect the bond strength of glass fiber post to root dentin?

The aim of this study was to evaluate if acid etching prior to application of different universal adhesives influences the bond strength of the glass fiber post to root dentin. One hundred and twenty (120) bovine-tooth roots were prepared to receive glass fiber posts #3 (White Post, FGM) and then divided into 12 groups (n = 10) according to two factors: the adhesive system (Single Bond Universal, Ambar Universal, Prime & Bond Universal, Gluma Bond Universal, YBond Universal or Ambar Universal APS); and acid etching prior to application of the adhesive (presence or absence). After cementation, the specimens were stored in a humid environment at 37 °C for 24 h. Each sample was sectioned into 5 slices with 1.5 ± 0.2 mm thickness and subjected to a pushout test with an increasing load of 1 mm/min in a universal testing machine until failure and the data were analyzed using two-way ANOVA and post-hoc Tukey's tests. There was no statistical difference in the bond strength values for the acid etching factor. There were only differences for the adhesive system factor. Higher bond strength values were found for the Universal Single Bond adhesive (3 M) regardless of acid etching or not, and for Gluma Bond Universal adhesive without acid etching. It was possible to conclude that acid etching prior to applying the universal adhesives used in this study does not influence the bond strength of glass fiber posts to root dentin.