Comparative Evaluation of Fracture Resistance and Failure Patterns Among All-Resin Post and Core Designs: In vitro Study

Purpose: This in vitro study evaluated the fracture resistance of dual-cure resin cement and core build-up material (Core-X ® Flow) used as all-resin posts of two different lengths, compared with conventional fiber-reinforced posts, and to analyze failure patterns. Material and Methods: Thirty extracted human single-rooted mature teeth (premolars, canines, and maxillary central incisors) were endodontically treated and randomly assigned to three groups (n=10). Group A received a 10 mm fiber post with Core-X Flow, Group B received a 10 mm all-resin post with Core-X flow, and Group C received a 5 mm all-resin post with Core-X flow. Fracture resistance was evaluated under compressive loading using a universal testing machine, at a crosshead speed of 1 mm/min, and the failure patterns were assessed using a digital stereomicroscope. Data were analyzed using a one-way ANOVA (p> 0.05). Results: Fracture resistance did not differ significantly among the three groups (p> 0.05). Mean values were 430.28 N for Group A, 422.16 N for Group B, and 434.56 N for Group C. Failure mode analysis showed that Group C (5 mm all-resin posts) exhibited the highest number of favorable (repairable) fractures, followed by Group A (fiber posts) and Group B (10 mm all-resin posts). Conclusion: All-resin posts demonstrated fracture resistance comparable to fiber-reinforced posts. Shorter all-resin posts produced more favorable failure outcomes, suggesting that they may offer a conservative and clinically viable option for restoring endodontically treated teeth. These findings should be interpreted within the limitations of an in vitro design and small sample size.