Degree of conversion of bulk fill composites at different depths

Abstract

Aim: The aim of this study was to evaluate the degree of monomer conversion of bulk fill composites at different depths. Materials and methods: The bulk fill products tested were SDR™, SonicFill™ System, Venus® Bulk Fill, and Tetric Evo-Ceram® Bulk Fill. In addition, this study tested conventional composites that have been indicated for use in association with bulk fill composites (Venus® and Tetric EvoCeram®), as well as the Ceram X™ conventional composite. To analyze the degree of conversion (DC), specimens (n = 10) consisting of four individual portions through the depths of cure (1, 2, 3, and 4 mm) were created. These samples were ground, pressed with potassium bromine, and analyzed using Fourier-transform infrared (FT-IR) spectroscopy. Two-way analysis of variance (ANOVA) and Bonferroni post hoc methods were applied to the results (p < 0.05). Results: Venus® Bulk Fill exhibited the best results at all of the depths tested. None of the bulk fill composites considered herein exhibited any significant differences between the depths. Conventional composites were found to have significantly lower DCs at greater depths. Conclusion: The results show that when depth of cure is being considered, bulk fill composites may be used at thicknesses of up to 4 mm. Clinical significance: Bulk fill composites are indicated to be inserted in increments of up to 4 mm. In this sense, it is fundamental to determine DC in these depths to ensure obtaining adequate mechanical properties.