New monolithic post-core concept: a comparison of prefabricated and CAD-CAM fabricated post-cores

The aim of this in vitro study was to evaluate the fracture and pull-out strengths of various post-core systems.

Forty-eight endodontically treated maxillary central incisors were assigned to three post-core groups: fiber post-composite core (RelyX) (FC), prefabricated monolithic fiber post-core (FiberSite) (MF), and CAD-CAM fabricated customized monolithic zirconia post-core (InCoris ZI) (MZ). Post-core designs were standardized according to the FiberSite system. After cementation (RelyX U200), the samples were divided into two mechanical test groups-fracture strength and pull-out strength (n = 8 per subgroup). Tests were performed at a crosshead speed of 1 mm/min, and failure types were recorded.

For the fracture strength test, the highest values (N) were obtained in the MZ group. The difference between MF and FC was not statistically significant (p = 0.190). For the pull-out test, statistically significant differences (N) were found among all groups (p less than 0.001). The MZ group exhibited predominantly catastrophic failures in both tests, whereas the MF and FC groups mainly showed Type II and Type III failures.

Within the limitations of this study, the FiberSite system appears to have clinical potential for restoring severely damaged teeth. This system offers a balance of mechanical strength and favorable failure modes compared with CAD-CAM zirconia post-cores, which demonstrated catastrophic failures, and fiber post-composite cores, which exhibited lower strength values.