Strength of Incisors Restored by Metallic, Fiber and Ceramic Posts

Objectives: In endodontically treated teeth, because of extensive structural defects, the risk of fracture is increased. For reconstruction of coronal structure ,posts provide retention. Composite fiber posts were recently introduced to dentistry. This study compared the fracture strength of maxillary central incisors restored by metalic, fiber-reinforced composite and ceramic posts. Methods: 30 human maxillary central incisors were used. The crown of each incisor was cut off 1 mm coronally to C.E.J. perpendicular to long axis of the tooth by metal disc. Root canals of teeth were prepared for posts after RCT. Speciments were embedded in autopolimerizing acrylic resin 4 mm below the CEJ and then tested in a universal testing machine(Zwick-Germany). A compressive load was applied at 130 degrees to the long axis until fracture, at a cross-head speed of 0.5 mm/min. Fracture loads were recorded. All data collected were analyzed statistically using the ANOVA and LSD tests. Results: The mean and standard deviation (S.D.) of failure loads (in Newtons) were 765 +/- 113/265 N, 790+/- 95/34 N, 614+/- 105/32 N for glass-fiber, ceramic and metallic groups,respectively. ANOVA test detected statistically significant differences between all groups. Teeth restored with fiber and ceramic posts exhibited significantly higher resistance to fracture than with titanium posts. Teeth restored by fiber and ceramic posts were statistically simillar by LSD test. The highest proportion of undesirable fractures were seen with titanium posts. Conclusion: Usage of fiber and ceramic posts are preferable to titanium posts. Because of more undesirable fractures in the ceramic group than fiber group, use of the latter posts are recommended overall.