Marginal Microleakage Evaluation in Class II Cavities Restored With Composite, Resin-Modified Glass Ionomer, and Bulk-Fill Bioactive Composite: An In Vitro Study

Background: Restoring primary teeth with an aesthetic restorative material such as composite is a challenge in pediatric dentistry. Despite advancements, the ideal aesthetic restoration material remains just a debate. Thus, current studies are seeking to find a bio-restorative material to avoid composite negatives while maintaining cosmetic benefits. The bioactive composite is one of these materials, but its effectiveness and properties are still under study. This in-vitro study aimed to evaluate the marginal microleakage of class II cavities in primary molars restored with the bioactive composite and to compare it with the conventional composite and resin-modified glass ionomer (RMGI) cement. Methods: Overall, 45 standardized class II cavities were prepared in primary molars and restored with the bioactive composite, conventional composite, and RMGI according to manufacturers’ instructions. The restored teeth were subjected to 1000 thermocycles, followed by sealing the internal surfaces with wax before immersion in 0.5% methylene blue for 4 hours. Then, the teeth were sectioned mesiodistally to evaluate dye penetration under a microscope by two specialized pedodontists and according to a 4-degree scale. Results: Statistical analysis revealed no statistically significant difference in the marginal microleakage of occlusal and gingival surfaces among the bioactive composite, RMGI, and conventional composite (P values 0.104 and 0.160, respectively ). However, within the same group, a statistically significant difference was observed between occlusal and gingival surfaces in the bioactive composite, traditional composite, and RMGI, with lower occlusal microleakage (P values 0.020, 0.046, and 0.000, respectively). Multiple nominal logistic regression demonstrated no influence of being the molar upper or lower first or second on the marginal microleakage (P>0.05). Conclusion: Based on the present microleakage study, there was no significant difference between the microleakage values of the bioactive composite compared with the conventional composite and RMGI.