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UBC Theses and Dissertations

Restoration of endodontically treated immature teeth : influence of post fit on bonding properties of conventionally and adhesively luted fiber-reinforced composite posts Berthold, Christine

Abstract

Objective: To evaluate the influence of post fit and luting system on pull-out force and failure mode of conventionally and adhesively luted fiber-reinforced composite posts (FRCP). Methods: 260 extracted bovine deciduous teeth were randomly assigned to each of the four luting systems (Fuji Plus (FP), RelyX Unicem (RXU), Multilink Primer/Multilink (MLP_ML), LuxaBond/LuxaCore Z (LB_LCZ and three post fits (Congruency (C), medium incongruency (MIC), high incongruency (HIC)) (n=20/group). The teeth were decapitated, root canal treated, embedded and post space was prepared. The FRCPs (Macro-Lock Post sizes 1, 3 and 6) were pretreated and inserted, according to the manufacturer’s instructions. The custom-made titanium-post was inserted with Ketac Cem (control) (n=20). After water storage (24h, 37°C), pull-out test was performed. The data were analyzed using Kolmogorov-Smirnov test (p>0.05), Two-way ANOVA and post-hoc tests (Dunnett T3 with Bonferroni correction) (α=0.05). Failure mode was assessed using a stereomicroscope. Results: The influence of post fit and luting system was statistically significant (p<0.001), while the interaction of the two factors was not (p = 0.030). When comparing pull-out forces for the three post fits, significant differences (p < 0.017) were found between C (436.6±148.7 N) and MIC (426.0±102.1 N) and C and HIC (397.5±89.8 N). Failure mode was dominated by failure between dentin and luting system (64.2-70.7%) and between luting system and post (29.3-35.5%), for all post fit groups. Pairwise comparison revealed significant differences in pull-out force (p < 0.008) for all luting systems (FP: 441.2±44.9 N, RXU: 390.7±80.5 N, MLP_ML: 379.3±106.8 N, LB_LCZ: 544.0±96.6 N), except when comparing RXU and MLP_ML. Pull-out forces, achieved with all luting systems, were significantly higher compared to the control (211.2±35.1 N). The main failure for FP was found between luting system and post (92.3%) while main failure for RXU (99.5%), MLP_ML (95.8%), LB_LCZ (65.5%) was found between dentin and luting system. Conclusion: Post fit and luting system influenced the pull-out force of conventionally and adhesively luted FRCPs. Congruent post fit achieved the highest pull-out forces. The three-step Etch & Rinse adhesive luting system LB_LCZ generated considerably higher pull-out forces than all other tested luting systems.

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Attribution-NonCommercial-NoDerivs 2.5 Canada