Effects of fiber post and restoration type on endodontically treated maxillary premolars: finite element analysis and in vitro study

Abstract Objective To evaluate the influence of fiber post and ceramic restoration types (crown/onlay/overlay) on biomechanical behavior of endodontically treated maxillary premolars using finite element analysis (FEA) and in vitro fracture resistance test. Materials and Methods A three-dimensional model of an endodontically treated premolar with MOD cavity was generated. Different restoration scenarios were simulated, including CNP (crown with no fiber post), CP (crown with fiber post), OnNP (onlay with no fiber post), OnP (onlay with fiber post), OvNP (overlay with no fiber post), OvP (overlay with fiber post). A force of 300 N was loaded at a 45° angle to the occlusal surface. Von Mises stress values were analyzed. Same groups were further subjected to in vitro test using extracted human maxillary premolars. Fracture resistance data were analyzed using two-way ANOVA and Tukey’s HSD tests (α = 0.05). Fracture modes were documented and examined by scanning electron microscopy. Results FEA analysis demonstrated that premolars with ceramic overlays exhibited the lowest maximum Von Mises stress, regardless of fiber post. The insertion of fiber posts resulted in stress dispersion on the cervical segment of premolars, regardless of restoration type. In vitro study indicated that no significant differences existed in fracture resistance among six treatment groups. The proportion of restorable fractures was highest in the OvP group and lowest in the CNP group. Conclusions Restoration types did not significantly improve biomechanical behaviors of endodontically treated premolars. Placement of fiber post could reduce the onset of unrestorable fracture and achieve better biomechanical behaviors.