In-vitro Comparative Evaluation of Flexural Strength and Depth of Cure of Bulkfill Composite

Aims and objectives: Bulkfill composite resins have been used for the posterior restorations in an attempt to speed up the restorative process. Here 4 to 5mm thickness of composite resins can be placed andcured in asingle step so that time consuming layering technique can be eliminated. The purpose of this study was to investigate the flexural strength and depth of cure of two bulk fill composites and to compare it with a universal composite. Materials and method: Two bulk fill composites (Sonic fill and Filtekbulkfill) and one universal composite (Filtek Z350 XT) were used. Ten samples per group were made using rectangular split brass mold following ISO standard 4049 to measure the flexural strength. Each sample was then subjected to three point bend test using universal testing machine until failure occurred. For depth of cure measurements, ten samples per group were made using cylindrical brass mold and were subjected to acetone shake test for 30 sec. The dimensions of the samples were measured using Vernier callipers and compared. One-way analysis of variance followed by Tukey’s post-hoc test was used to determine the statistical differences among groups at significance of p<0.05. Results: Sonicfillgave highest flexural strength value and Filtek Z350 XT the least. There was no statistically significant difference between the flexural strength of Filtekbulkfill and Filtek Z350 XT. For depth of cure, Filtekbulkfill showed higher value than other tested groups. Conclusion: All the tested materials showed significantly higher flexural strength values than the minimum flexural strength (80MPa) that is required for use in stress bearing areas. Sonicfill composite produced highest value of flexural strength than other composites, which may bedue to its increased percentage of filler content. For depth of cure, both the tested bulkfill composites showed lesser value of depth of cure than that claimed by manufacturers .