Fracture Resistance of Endodontically Treated Teeth Restored with High-Viscosity Bulk-Fill Resin Composites

ABSTRACT Objective: To evaluate the fracture resistance of endodontically treated teeth restored with different high-viscosity bulk-fill resin composites. Material and Methods: Forty extracted human upper premolars were endodontically treated and divided into four groups based on the bulk-fill resin composite used: CO: Scothbond Multi-Purpose + Fütek Z3S0XT; SF: Scothbond Universal + Fütek Bulk Fill; SO: OptiBond All-in-one + SonicFill; and, TT: Tetric N- Bond Universal + Tetric N-Ceram Bulk Fill. Universal adhesive systems were applied using the self-etching technique. After 24 hours, specimens underwent compressive loading at lmm/min, and fracture patterns were evaluated. Data were statistically analyzed using one-way ANOVA and Tukey’s post-test (p>O.OS), while fracture patterns were assessed with the chi-square test (p<O.OS). Results: Fracture resistance was similar across groups (p>O.OS), with favorable fractures observed in the CO and SF groups. Conclusion: The fracture resistance of endodontically treated teeth restored with bulk-fill resin composites does not differ from those restored with conventional nanohybrid resin composites.