Fracture resistance and bond strength of endodontically treated teeth, restored with three fiber post and core system: an in vitro study

Fracture resistance of endodontically treated teeth depends on multiple factors including residual dental structure, type of post, diameter, and design of post itself. Aimed to evaluate fracture resistance and push-out bond strength of endodontically treated teeth, restored with three fiber post material and their modes of failure. Twenty-seven newly extracted mandibular second premolars were obtained for this study. Teeth were randomly allocated into three groups based on post type (n = 9). Group (RP): Tapered fiber post, group (RGP): Bundle fiber post and group (CP): parallel-sided fiber post. After root canal preparation and obturation, standardized post spaces were prepared and core-build up was done. Fracture resistance and push-out for all samples were evaluated using the universal testing machine under the speed of 0.5 mm/min at 45-degree sloping load which were applied to the restored teeth. The data was collected and statistically analyzed using Kruskal Wallis test. Mode of failure was assessed using a stereomicroscope. There was no statistically significant difference between the three study groups regarding the fracture resistance values (p value 0.552). Kruskal Wallis test revealed that there was no statistically significant difference in push-out values among the three studied groups (p value 0.435). Bundle fiber posts showed similar fracture resistance values in comparison to tapered fiber posts and parallel-sided fiber posts. Regarding fracture resistance and push-out bond strength the highest values were showed in group RP and the lowest values were presented in group RGP.