ABSTRACT
The objectives of this study were to compare the microhardness, flexural strength and compressivestrength of a new bulk-fill composite (SonicFill™) to a conventional nanohybrid composite (HerculitePrecis) and an established bulk-fill composite (Tetric N Ceram). In addition, the depth of cure of thetwo bulk-fill resin composites was also investigated. The materials were prepared and tested for themechanical properties following ISO 4049:2009. Microhardness and depth of cure were measured usingVickers hardness tester. Compressive and flexural strength were tested using a universal testing machine.To determine the depth of cure, microhardness of the bulk-fill composites were measured as a functionof selected depth of materials at 0.5 mm, 2.0 mm and 4.0 mm. Data were analyzed by either one-wayANOVA or Friedman test. Analysis demonstrated that SonicFill™ gave the highest microhardness value(101.8 + 4.6 VHN) compared to the other two groups. There were no significant differences among allgroups in flexural and compressive strength. The depth of cure decreased as the thickness of both bulkfillcomposites increased. In conclusion, SonicFill™ showed favorable mechanical properties comparedto other composites tested. In both bulk-filled groups, microhardness value decreased as the thicknessof the composite increased. The polymerization of the bulk-filled composites was effective only at 2 mmor less.