Comparative Evaluation of Fracture Resistance in Endodontically Treated Teeth Using Four Intraorifice Barrier Materials – An In Vitro Study

Aim: This study aimed to compare the fracture resistance of endodontically treated mandibular premolars using four different intraorifice barrier materials.Materials and methods: Fifty extracted single-rooted mandibular premolars were decoronated, instrumented and obturated.The coronal 3 mm of gutta-percha was removed.Specimens (N = 50) were divided into five groups based on intraorifice barriers: Group I: Glass ionomer cement (GIC); group II: Polyalkasite cement (Cention N); group III: Bonded amalgam; group IV: Nanohybrid bulk-fill flowable composite; group V: Control (no barrier).After material placement, fracture resistance was measured using a universal testing machine under a vertical compressive load.Statistical analysis was performed using one-way analysis of variance (ANOVA) and post hoc Dunnett T3 test (p < 0.05). Results:The mean fracture resistance values (in Newtons) were: Bonded amalgam (875.14 ± 17.95 N), composite (679.95 ± 15.27 N), GIC (585.77± 5.13 N), polyalkasite cement (Cention N) (461.86 ± 13.37 N) and control (407.94 ± 5.98 N).Statistically significant differences were found among the groups (p < 0.0001).Bonded amalgam differed significantly from all groups, and the composite group showed significant differences when compared with polyalkasite cement (Cention N) and the control.Conclusion: Bonded amalgam and nanohybrid bulk-fill flowable composite resin, when used as an intraorifice barrier, had a significantly higher fracture resistance when compared to teeth without an intraorifice barrier. Clinical significance:In the present study, the use of bonded intraorifice barriers, whether bonded amalgam or nanohybrid bulk-fill composite, can enhance the structural durability of endodontically treated teeth, potentially improving clinical outcomes.