Evaluation of push-out bond strength of four luting agents and SEM observation of the dentine/fibreglass bond interface

Abstract

Aim: To assess the dentine/fibreglass-bonded interface by scanning electron microscopy and the push-out bond strength of four luting cements.

Methodology: Forty root-filled human canines, with similar root lengths, were restored with fibreglass posts and randomly divided into four groups according to the cements employed (CG Gold Label I, RelyX ARC, BisCem and RelyX U100). After standardized post-space preparation, the root dentine was pre-treated for dual-polymerizing resin cements and untreated for the other cements. The mixed luting cement paste was inserted into root canals with a spiral filler and applied to the post-surface that was seated into the root canal. After 7 days, the teeth were sectioned perpendicular to their long axis into 1-mm-thick sections and submitted to a push-out test (1 mm min(-1)). Statistical analyses were carried out by two-way anova and Tukey's tests (P < 0.05).

Results: The bond strength was significantly affected by the type of cement (P < 0.001) and by the longitudinal region of the root canal (P < 0.031). All cements exhibited gaps at the dentine/cement interface.

Conclusions: The self-adhesive materials and the glass ionomer cements had the highest push-out bond strength values when compared with the dual-curing resin cement.

Keywords: SEM; fibreglass post; luting procedures; push-out bond strength; root canal filling.