A Comparison of the Fracture Resistance of Endodontically Treated Teeth Using Two Different Restoration Systems

Many post systems are available to clinicians, yet no consensus exists regarding the superiority of any one in restoring endodontically treated teeth. The aim of this in vitro study was to compare the fracture resistance and failure mode of endodontically treated teeth restored with a cast metal post and crown with quartz fiber post and composite crown build-up. Methods: Forty extracted maxillary canine teeth with similar size were chosen and randomly divided into 2 groups. After cutting the crowns and endodontic therapy, the teeth were restored with a quartz fiber post and composite crown build-up, or a cast metal post and crown in group 1 and 2, respective- ly. Fiber posts were cemented with dual cured resin cement and cast posts were luted using zinc phosphate cement. After thermocycling, a compressive load was applied at 135˚ C to the long axis of the tooth at a crosshead speed of 1 mm/min and fracture loads and fracture modes were recorded. Mann-Whitney and t tests were used to determine the significance of the failure load values between the two groups. Results: The mean values for fracture strength in groups 1 and 2 were 344 and 446 N, respectively. The teeth in group 2 exhibited significantly higher resistance to fracture (P < 0.01); however, all fail- ures occurred in the tooth structure. Conclusion: In spite of the significantly lower failure loads achieved for the teeth restored with fiber posts, all of the fractures in this group were repairable.