Evaluation of the degree of conversion of flowable bulk fill and dual-cure composite resins for intracanal root reinforcement in teeth with structurally weakened roots: An in vitro Fourier transformer infrared study

Context: Comparison of the degree of conversion (DC) of resin composites for reinforcement of structurally weakened roots. Aims: To compare the DC of flowable bulk-fill resin composites (BFRCs) and dual-cure resin composite (DCRC) at different depths for root reinforcement material using Fourier-transform infrared spectroscopy analysis. Materials and Methods: The study included a total of 24 samples from four different resin composite materials, namely Tetric N Flow BFRC (Group 1), Filtek flowable bulk fill composite resin (Group 2), smart dentin replacement (SDR) (Group 3), and ParaCore DCRC (Group 4). These materials were placed into Teflon molds and light-cured. The samples were sectioned into three segments and pulverized. The powdered samples were then mixed with potassium bromide powder in a ratio of 1:100 and subjected to Fourier-transform infrared spectroscopy analysis. Statistical Analysis: The data were statistically analyzed using SPSS software using parametric tests. Results: ParaCore dual-cure composite showed the highest DC among all the materials tested, followed by SDR, Filtek bulk fill flowable resin composite, and Tetric bulk fill flowable resin composite. The results of one-way ANOVA revealed a statistically significant difference, P ≤ 0.05 (0.000). The post hoc Tukey HSD test revealed a statistically significant difference between groups 1, 2, 3, and 4 ( P < 0.0001). Conclusion: When the DC is inadequate, the physical, mechanical, and biological properties of the resin composite are compromised. Therefore, dual-cure resins could be better suited to be used for root canal reinforcement.