Fracture Resistance of Different Post-core Systems Restoring Mandibular Premolars

Objective: This in vitro study aimed to compare the fracture resistance between Milled Custom-made PEEK post and core, Pressed custom-made PEEK post and core and Customized fiber post and composite core. Materials and Methods: A total of 21 human mandibular premolar teeth with similar root form and root canal shape averaging cervico-occlusal length of the crown about 8+/-0.5 mm and 14.5+/-0.5 mm for root length were collected for this study, endodontic treatment was performed for all teeth followed by coronal decapitation 2mm above CEJ and post space preparation, After the preparation of each root, the corresponding teeth were allocated randomly to three groups (n=7/ group) according to the type of material and fabrication technique used to generate the post-and-core: GM, milled PEEK post and core; GP, pressed PEEK post and core; GC, customized fiber post and composite core. Results: There was a significant difference between different groups (p < 0.001). PEEK milled group showed the highest mean fracture resistance value (1055.25±119.31 N) followed by PEEK pressed group (963.39±117.28 N) while customized fiber post group (625.85±69.69 N) showed the lowest mean value. Conclusion: On the basis of the results and conditions of this study, the following conclusions can be drawn: 1- PEEK post and core made by two fabrication techniques have surpassed the fracture resistance values of customized fiber post. 2- With the widespread of in-office CAD/CAM systems, milled PEEK may represent viable alternative for dental post materials according to the tested parameters.