Push-out bond strength of CAD/CAM-fabricated modified PEEK dental posts

This study aimed to evaluate the bond strength to dentin of dental posts fabricated with different PEEK using the push-out test, while also examining the failure modes. Sixty mandibular premolars extracted for periodontal reasons were randomly allocated into three groups (n = 20 each). The custom post-cores were fabricated using CAD/CAM from 3 PEEK disks: unfilled PEEK (Group UP); 20% TiO2-filled PEEK (Group TP); 20% ceramic-filled PEEK (Group CP). Monobond Plus and visio.link adhesives were used for bonding. Following cementation, 180 dentin disks were obtained by sectioning each tooth into 1 mm segments from the coronal, middle, and apical thirds. Subsequently, the push-out bond strength (PBS) test was performed. Data were analyzed using MANOVA and Tukey’s HSD tests (α = 0.05). There was no significant difference between the bonding agents in Group CP. In Group UP, Visio.link exhibited significantly higher push-out bond strength (PBS) than Monobond Plus in the middle and coronal thirds, while in Group TP, this superiority was observed in the apical and middle thirds. Among the tested post materials, Group CP demonstrated the highest overall PBS values, which were significantly greater than those of Group TP, though not significantly different from Group UP. The highest PBS values were consistently found in the coronal third, followed by the middle and apical thirds. Ceramic-filled PEEK posts achieved the greatest bond strength, and Visio.link outperformed Monobond Plus as a bonding agent. A gradual decrease in PBS from the coronal to the apical thirds was observed across all groups. Within the limitations of this in vitro study, ceramic-reinforced PEEK posts provided the highest push-out bond strength to root dentin. The Visio.link bonding agent demonstrated superior performance compared to Monobond Plus, and the PBS of PEEK posts decreased progressively from the coronal to the apical third. Careful selection of both the PEEK post type and the bonding agent is essential to enhance the retention and clinical success of custom PEEK post-core restorations in endodontically treated teeth.