Abstract
Background: Root-filled teeth are structurally and biomechanically weakened, and the choice of post-endodontic restoration is important. This study aimed to compare the fracture resistance and fracture patterns of root-filled maxillary premolars restored with different post systems and composite-based post-space restorations.
Methods: 100 extracted maxillary second premolars were root canal treated and randomly allocated to five groups (n=20): metal post (Group A), fibre post (Group B), flowable composite in the post space (Group C), fibre-reinforced composite in the post space (Group D), and composite restoration without post with a glass ionomer orifice barrier (control, Group E). All specimens received a standardised mesio-occluso-distal (MOD) cavity preparation with preservation of the buccal wall and were restored with nanohybrid composite before axial loading in a universal testing machine to determine fracture resistance. Meanwhile, fracture patterns were classified under a stereomicroscope.
Results: Mean (± standard deviation) fracture resistance values were metal post (896.26 ± 335.55 N), fibre post (1046.64 ± 336.65 N), flowable composite (937.94 ± 323.83 N), fibre-reinforced composite (799.90 ± 244.43 N), and control (973.54 ± 357.33 N), with no statistically significant differences among groups (p=0.175). Metal and fibre post groups predominantly exhibited favourable, restorable Class 2 fractures, whereas flowable composite, fibre-reinforced composite, and control groups mainly demonstrated Class 3 or Class 4 fractures.
Conclusion: Root-filled teeth restored with or without posts show similar fracture resistance. Fibre and metal posts, however, produced more favourable fracture patterns, suggesting that posts can influence failure mode even without increasing overall fracture strength