JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, cilt.30, sa.6, ss.633-641, 2016 (SCI-Expanded)
This study assessed the effect of timing of core preparation and luting cement on adhesion of fiber-reinforced composite (FRC) posts on different levels of intraradicular dentin when cemented with either conventional dual-polymerized or self-adhesive resin cement. Single-rooted human teeth (N=80) were endodontically treated and randomly divided into 2 groups (n=40) according to resin cement: (a) Conventional dual resin cement (Variolink II, V) or (b) Self-adhesive resin cement (RelyX U200, R). They were further divided into two subgroups according to timing of core preparation (n=20): (a) immediate (i) or (b) delayed (d). FRC posts (Cytec Blanco) were cemented and the roots were sliced into discs at the coronal, middle, and apical levels. Push-out tests were then performed in a Universal Testing Machine (1mm/min). Data (MPa) were analyzed using three-way ANOVA and Tukey's tests considering the factors core preparation time', luting cement', and root level' (=0.05). Type of luting cement (p<0.001), time of core preparation (p<0.001), and root level (p<0.001) significantly affected the bond strength results. R cement was more significantly affected by core preparation time (Ri: 2.91 +/- 1.1; Rd: 4.83 +/- 1.68) compared to V cement (Vi: 2.92 +/- 1.63; Vd: 2.65 +/- 1.6) (p<0.05). Coronal region demonstrated significantly higher bond strength values than those of middle and apical third in all groups (coronal: 4 +/- 1.9; middle: 3.1 +/- 1.4; apical: 2.4 +/- 1.1) (p<0.05). Adhesive failure between cement and dentin was the most frequent (64%) followed by adhesive failure between cement and post (18%). Delayed core preparation can improve bond strength of FRC posts to intraradicular dentin when cemented with self-adhesive cement compared to conventional dual-polymerized resin cement.