Effect of Curing Modes of Dual-curing Luting Systems and Root Regions on Retention of Translucent Fiber Posts in Root Canals

Purpose: To evaluate the effect of different curing modes of dual-curing luting systems and root regions on the pushout strength of fiber posts to intraradicular dentin. Materials and Methods: Forty-two extracted premolars with a single root canal were sectioned at the cementoenamel junction and the roots were endodontically treated. The roots were divided into two groups according to two dual-curing luting systems: (1) XP BOND-Dual Cure/Calibra resin cement; (2) XP BOND-Dual Cure/FluoroCore 2. For each luting system, three different curing modes were applied to the dentin adhesive and resin cement: "Self-cure and Self-cure (SC&SC)", "Self-cure and Dual-cure (SC&DC)", and "Dual-cure and Dual-cure (DC&DC)". Translucent Easy fiber posts (Dentsply Maillefer) were luted in the roots. A thin-slice push-out test was performed, and the data of push-out strength were analyzed using three-way ANOVA with luting system, curing mode, and root region (apical, middle and coronal) as factors. Tukey's test was used for post-hoc comparisons. Results: The push-out strength of XP BOND-Dual Cure/Calibra was significantly lower when Calibra resin cement was self-cured than when it was dual-cured (SC&SC: 6.04 ± 2.65 MPa; SC&DC: 10.69 ± 3.01 MPa; DC&DC: 10.72 ± 3.63 MPa; p 0.05). The curing modes did not affect the push-out strength of XP BOND-Dual Cure/FluoroCore 2 (SC&SC: 7.90 ± 3.94 MPa; SC&DC: 8.32 ± 2.73 MPa; DC&DC: 9.27 ± 4.12 MPa; p > 0.05). The coronal push-out strength was significantly higher than the apical push-out strength (p 0.05). Conclusion: Retention of fiber posts in root canals was affected by the curing modes of dual-curing luting system and root regions. Keywords: curing modes, push-out strength, fiber post, root region