Comparison of the Fracture Resistance of Endodontically Treated Maxillary Incisors Restored with Six Different Post and Core Systems

Background and Aim: Different methods and materials are available for post and core (P C) fabrication. We aimed to compare the fracture resistance and failure modes of endodontically treated maxillary central incisors restored with six different P C systems. Materials and Methods: In this in-vitro study, after endodontic treatment and coronal preparation of 60 maxillary central incisors, six different P C systems were used: 1) cast base metal P C, 2) cast gold alloy P C, 3) zirconia post and casting ceramic core, 4) zirconia post and composite core, 5) titanium post and composite core, and 6) fiber post and composite core. Thermocycling (5-55°C, 60 seconds, 1500 cycles) was performed after cementing the full metal crowns on each tooth. A 130° force was applied at a crosshead speed of 1.5 mm/minute in a universal testing machine. The fracture force (N) and fracture patterns were recorded. Data were statistically analyzed by using Kruskal-Wallis, Mann-U-Whitney, and Fisher’s exact tests (α=0.05). Results: The highest mean fracture resistance was recorded in the first group (904±302.77 N) followed by the third group (725±202.11 N), second group (723±224.15 N), fourth group (675±358.64 N), fifth group (424±156.85 N), and sixth group (416.5±81.58 N). The groups with casting P Cs and zirconia post and casting core showed significant differences with the other two groups with non-casting cores (P 0.001). Conclusion: The highest fracture resistance was recorded for cast metal P C, which may be due to a better stress distribution. Zirconia post and ceramic core may be a proper and aesthetically appealing substitute for cast metal P C.