Evaluation of mechanical properties of different polyetheretherketone endodontic post systems: An in vitro study

Background: Survival of endodontically treated teeth depends on efficiently restoring the missing tooth structure. Objectives This study is designed to assess the mechanical properties of different endodontic post systems. Materials and methods Human permanent maxillary central incisors (no.=58) of the same size were decorated and root-filled, and the post spaces were prepared up to 9.0 mm. Then, the specimens with prepared root canals were randomly divided into two groups; Group P allocated a prefabricated polyetheretherketone (PEEK) post and composite core, while Group C allocated a custom-made post-core of PEEK. The cementation of the posts was carried out using self-adhesive resin cement, while the nano-hybrid composite resin was used for core fabrication. After cementation, the specimens from each group were randomly divided into two subgroups according to the types of tests utilized. Of these, 28 samples (14 from each group) were for the fracture strength test, which was restored with IPS e-max CAD crown, and 30 samples (15 from each group) for the pullout resistance test. A universal testing machine was used for the test performance. Results The fracture resistance test showed that the values were significantly different among tested posts ( P  = 0.013). Group P showed the highest fracture resistance. The custom-made one-piece post and core PEEK post group (C) exhibited higher mean values of pullout resistance compared with the other group (P) ( P  = 0.059). In the two-piece PEEK post and composite core, the predominant type of failure was core displacement or fracture, while in the one-piece PEEK post-core, most types of losses were either in the crown or in the post. Conclusions The prefabricated posts are more resistant to fracture than the custom-made posts with fracture and displacement mainly of the core. In contrast, both showed similar pullout resistance.