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.