Fracture Resistance of Tilted Premolars Restored with Different Post-Core Systems.

Aims and Objective: To assess the effect of root tilt on the fracture resistance and failure pattern of endodontically-treated premolars restored with different post-core systems.

Materials and Methods: Ninety endodontically-treated premolars were mounted in acrylic blocks with 0°, 12°, and 24° axial root tilt. Teeth in each group were restored in three subgroups with cast post-core, readymade metal posts and composite cores, and fiber post and composite cores. Crowns of all teeth were prepared coinciding with the long axis of the acrylic blocks to receive all-ceramic crowns. All restored teeth were stressed to record the maximum load at failure and the associated failure pattern. The collected data were statistically analyzed using two-way ANOVA, Tukey's, and Kruskal-Wallis tests at α = 0.05 on past software to detect any differences between subgroups.

Results: Analysis of the collected data indicated significant differences between the tested subgroups (ANOVA, P = 3.86). Further analysis showed significant difference between all test subgroups and the control (Tukey's, P < 0.05). In general, teeth with 0° tilt seemed more resistant to fracture than the tilted ones. For all groups, teeth restored with fiber post and composite cores (SG3) were more resistant to fracture compared to other post-core systems (SG1 and SG2) (Tukey's, P < 0.05). The root fracture was the most commonly seen mode of failure.

Conclusions: Root tilting usually affects the fracture resistance of teeth restored with post-core systems. The fiber post and composite cores seemed to be the best choice to restore teeth with different root tilting possibilities.