Fracture resistance of polyetheretherketone, Ni‑Cr, and fiberglass postcore systems: An in vitro study

Abstract

Background: It is unclear which the material is a better choice for post and core rehabilitation
systems in endodontically treated teeth. This study aimed to compare the fracture resistance of
three different postcore systems.
Materials and Methods: In this in vitro study, 33 extracted premolars were treated endodontically
and divided into three groups, namely (A) the prefabricated fiberglass postcomposite core, (B)
the Ni‑Cr cast postcore, and (C) the polyetheretherketone (PEEK) postcore groups. After
postcementation, the core was restored with Ni‑Cr crown. By a universal testing machine, the
fracture resistance of the posts was assessed. Furthermore, types of fractures were determined
with radiography and confirmed objectively by cutting the acryl resin boxes. The data of the
fracture resistance were analyzed using the one‑way ANOVA and Tukey test, and the data of the
fracture pattern were analyzed using Fisher’s exact test (P < 0.05).
Results: The fracture resistance was significantly higher in Group B (Ni‑Cr) than in
Group C (PEEK) (P = 0.001) and Group A (fiberglass) (P < 0.001). Moreover, the fracture
resistance was higher in Group C (PEEK) than in Group A (fiberglass) but was not statistically
significant (P = 0.405). The fracture pattern was different in all the groups based on the types of
fracture (P = 0.009) and the repairability of fracture (P = 0.036).
Conclusion: The present study showed that the fracture resistance was significantly higher in the
Ni‑Cr post than in the fiberglass and PEEK posts. Further, the fracture mode was more repairable
in teeth restored with the PEEK post, as compared to the other posts.
Key Words: Bicuspid, Fiberglass, Polyetheretherketone, post and core technique