Impact of Contact Time on Push-out Bond Strength of Intra-orifice Barrier Materials in Temporary Restorations

Background and Aim: The use of intra-orifice barriers helps reduce coronal leakage, enhances sealing of the intra-orifice area, and improves the success rate of root canal therapy. This study aimed to investigate the effect of contact time on pushout bond strength (PBS) of intra-orifice barrier materials in temporary restorations. Materials and Methods: This in vitro study used 110 single-rooted teeth decoronated at 2 mm below their cementoenamel junction. After access cavity preparation, the samples were divided into two experimental groups of Cavit and Zonalin and two control groups of positive control and negative control. The Cavit and Zonalin groups were further divided into subgroups based on the duration of temporary restoration application (2 weeks and 4 weeks) and type of barrier material [flowable composite and resin-modified glass ionomer (RMGI)]. Dentinal blocks were prepared, and samples were subjected to a PBS test. Data were analyzed using a generalized linear model and the Kruskal-Wallis test (alpha=0.05). Results: General comparison revealed a statistically significant difference among the experimental groups in PBS (P=0.000). Pairwise comparisons showed that the Cavit-4 weeks-flowable composite subgroup exhibited the highest PBS (6.70 ± 1.76 MPa), which was significantly greater than the PBS of all other combinations (P=0.000). The positive control group (cotton pellet dipped in eugenol-2 weeks-flowable composite) showed the low est PBS (0.302 ± 0.101 MPa) . Conclusion: Cavit temporary restorative material significantly enhanced the PBS of flowable composite barrier after 4 weeks, outperforming other materials and time combinations.