Reinforcing the lost margins with different approaches: An in vitro study

Aim: This study aimed to evaluate the fracture resistance of different restorative techniques in endodontically treated teeth with Mesial Occlusal Distal (MOD) cavities. Subjects and Methods: Sixty mandibular molars that were extracted were prepared with standardized MOD cavities and received root canal treatment. Samples were allocated randomly across four groups: Group 1 – preimpregnated glass fiber reinforced-composite (Interlig, Angelus, Brazil); Group 2 – invasive horizontal glass fiber posts (Waldent radiopaque fiber post, Waldent, India); Group 3 – noninvasive horizontal glass fiber posts (Waldent radiopaque fiber post, Waldent, India), and Group 4 – prepolymerized composite resin inserts. Fracture resistance was assessed using a universal testing machine, and the resulting data were subjected to statistical analysis using the analysis of variance (ANOVA) and Tukey’s post hoc test. Results: The preimpregnated braided glass fiber reinforced-composite group showed the highest mean fracture resistance (2811.80 ± 227.83 N), followed by the noninvasive horizontal post group (2652.67 ± 191.59 N). The prepolymerized composite resin inserts group (1853.87 ± 210.59 N) had moderate resistance, while the invasive horizontal post group (1338.00 ± 187.05 N) exhibited the lowest values. Significant differences among groups were confirmed by ANOVA and post hoc tests ( P < 0.05). Conclusion: Within the study’s limitations, preimpregnated glass fiber reinforced-composite provided the highest fracture resistance in endodontically treated MOD cavities, with noninvasive horizontal posts outperforming invasive posts. Preserving tooth structure through conservative glass fiber reinforcement yields superior clinical outcomes.