Evaluation of voids in class ii restorations restored with bulk-fill and conventional nanohybrid resin composite

Abstract

Objectives: The aim of the study was to evaluate the influence of four resin composites on voids in small and large Class II cavities. Furthermore, the thickness of the first increment of the restorations was studied. Methods: Eighty artificial lower second premolars were divided into two preparation designs with 40 standardized Class II cavities in each, and then restored with four resin composites (three bulk-fill types: SonicFill 2, Filtek Bulk Fill (capsule), Filtek Bulk Fill (syringe) and a conventional nanohybrid resin composite: Premise). Restorations were sectioned for microscopic evaluation and a Kruskal-Wallis analysis was performed to evaluate the number of voids and percent void area. The thickness of the first increment was measured and analyzed. Results: There were significant differences in the number of voids and percent void area among the 4 groups in small cavities. SonicFill 2 and Filtek Bulk Fill (capsule) placed with the injection technique showing reduced voids. In contrast, no significant differences were detected among the 4 groups in large cavities. Most of the first increment thicknesses of the restorations in both cavity preparations were thicker than recommended. Conclusions: Voids were reduced when the injectable resin composites were applied in small Class II cavity preparations, and the best results were achieved using SonicFill 2.