Effect of Resin Cements on the Bond Strength of Three Types of Glass Fiber Post Systems to Intraradicular Dentin

Aim: The aim of this study was to evaluate the effect of different GFP systems on BS to intraradicular dentin using two dual-curing resin cement types.

Materials And Method: Thirty bovine incisors with wide canals were filled endodontically with gutta-percha and epoxy resin sealer. Initially, the canal filling was removed, and 4 mm of the apical seal was left intact. The teeth were divided into three groups according to the GFPs used: AP (anatomical posts - prefabricated GFP (Reforpost #2, Angelus®) relined with composite resin (Filtek Z350, 3M ESPE); SPLENDOR (Splendor SAP, Angelus®), and milled CAD/CAM (FiberCAD, Angelus®). Posts were fixed with conventional (RelyX Ultimate, 3M ESPE) or self-adhesive resin cement (RC) (RelyX U200, 3M ESPE), following the manufacturer's instructions. After 48 h, the roots were sectioned into thirds and subjected to pushout BS testing using a universal testing machine. BS data were analyzed using Wilcoxon and Mann- Whitney U tests. Failure modes were assessed with Fisher's Exact test (α=0.05).

Results: In the apical and middle root sections, BS was similar in the AP and Splendor groups, both of which performed better than the milled CAD/CAM group (p≤0.05). In the cervical section, BS was significantly higher for the anatomical posts than for Splendor and milled CAD/CAM posts. Self-adhesive RC promoted statistically lower BS compared to conventional RC for the milled CAD/CAM post in the cervical and middle thirds (p≤0.05). Self-adhesive RC provided statistically higher bond strength than conventional RC for the anatomical post in the apical third (p≤0.05). No significant difference in failure modes was observed between resin cements and different root sections (p>0.05).

Conclusion: The BS of the GFP system was affected by resin cement type and root section, with composite resin-relined anatomically shaped posts generally performing better.