Influence of Post Material and Cement Type on the Retention of Prefabricated Posts in Endodontically Treated Teeth

Purpose: This in vitro study aimed to evaluate the effects of post material and cement type on the pull-out force of prefabricated glass-fiber, PEEK, and PEKK posts. Methods: Sixty extracted human mandibular premolars were prepared with standardized root canals and allocated into six groups (n = 10) according to post material (glass-fiber, PEEK, PEKK) and luting cement (resin or glass ionomer). PEEK and PEKK posts were CAD-CAM fabricated from prefabricated discs. All specimens underwent thermocycling (6000 cycles, 5–55 °C) prior to pull-out force testing on a universal testing machine, and failure modes were classified as adhesive, cohesive, or mixed. Because variance homogeneity was not satisfied, pull-out force values were logarithmically transformed (Log10) before two-way ANOVA and Bonferroni-adjusted post hoc analyses. Results: Post material (p = 0.026), cement type (p < 0.001), and their interaction (p = 0.012) significantly influenced pull-out force. Under resin cement, no statistically significant differences were detected among glass-fiber, PEEK, and PEKK posts. Under glass ionomer cement, PEEK and PEKK posts demonstrated significantly higher pull-out force than glass-fiber posts. The highest mean pull-out force was observed for glass-fiber posts luted with resin cement. The effect of post material on pull-out force was dependent on the luting cement. PEEK posts luted with resin cement showed no significant difference in pull-out force compared with conventional glass-fiber posts, supporting their potential as an alternative post material. Further studies are needed to evaluate the clinical performance of PEEK posts.