An in vitro comparative evaluation of three different intra-orifice barriers at different thicknesses on fracture resistance of endodontically treated teeth

Aim: This study aimed to evaluate and compare the effect of three different intra-orifice barrier (IOB) materials – dual cure resin (DCR) cement, Giomer, and Biodentine – at two depths (3 mm and 5 mm) on the fracture resistance of endodontically treated teeth (ETT). Methods: Thirty-five extracted single-rooted human teeth were biomechanically prepared and obturated with gutta-percha. Following obturation, specimens were randomly allocated into seven groups based on the IOB material and placement depth. Groups 1 and 2 received DCR cement at 3 mm and 5 mm, respectively; Groups 3 and 4 received Giomer at 3 mm and 5 mm; Groups 5 and 6 received Biodentine at 3 mm and 5 mm; Group 7 served as the control without any barrier. All samples were stored in 100% humidity at 37°C for 1 week. Subsequently, the specimens were mounted in acrylic and subjected to vertical compressive load using a universal testing machine to determine fracture resistance. Results: All IOB groups demonstrated significantly higher fracture resistance than the control group. Among the tested materials, Biodentine yielded the highest fracture resistance, followed by Giomer and DCR cement. In addition, barriers placed at 5 mm depth showed significantly superior resistance compared to those at 3 mm. Statistical significance was confirmed using one-way analysis of variance and Post hoc Tukey tests (SPSS v23). Conclusion: IOBs enhance the fracture resistance of ETT, with greater reinforcement observed at 5 mm placement depth. Biodentine, especially at 5 mm, was the most effective material, emphasizing the benefit of deeper placement of bioactive barriers in reinforcing ETT.