Effect of timing for core preparation, luting cement type and root level on adhesion of fiber posts to intraradicular dentin

Abstract

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 (1 mm/min).Data (MPa) were analyzed using three-way ANOVA and Tukey`s tests considering the factors "core preparation time", "luting cement" and "root level" (α=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.

Tensile Strength and Failure Types of Direct and Indirect Resin Composite Copings for Perio-Overdentures Luted Using Different Adhesive Cementation Modalities

“…The results of this study were comparable with those of Perez et al, where a 7 to 8 MPa bond strength was reported [30]. On the other hand, the results were higher than those of Sukuroglu et al [31] where adhesion results ranged between 3.8 and 5.6 MPa in the coronal region of the root. Both of these studies [30,31] reported push-out bond strength results whereas in this study tensile bond strength was measured.…”

“…On the other hand, the results were higher than those of Sukuroglu et al [31] where adhesion results ranged between 3.8 and 5.6 MPa in the coronal region of the root. Both of these studies [30,31] reported push-out bond strength results whereas in this study tensile bond strength was measured. Nevertheless, the use of dual polymerized cement in this study resulted in higher bond strength values with self-adhesive cements [30] in the coronal parts of the intraradicular dentin.…”

“…This finding clearly indicates that not only the adhesion of the resin materials to the root dentin but also the cohesive strength of the coping material affects the forces required to debond the coping. It also has to be noted that both the resin composite and the resin cement were methacrylate-based resin materials and all copings were cemented to the coronal portion of the root where improved adhesion has been reported compared to those of middle and apical parts [30][31][32]. Since higher results were obtained with all indirect methods (ICV, ICT, IDS), compared to direct method (DC), indirect coping fabrication method could be considered to provide more favorable mechanical properties, cemented either using resin composite or dual-polymerized resin cement.…”