The objectives of this study were to compare the microhardness, flexural strength and compressive
strength of a new bulk-fill composite (SonicFill™) to a conventional nanohybrid composite (Herculite
Precis) and an established bulk-fill composite (Tetric N Ceram). In addition, the depth of cure of the
two bulk-fill resin composites was also investigated. The materials were prepared and tested for the
mechanical properties following ISO 4049:2009. Microhardness and depth of cure were measured using
Vickers 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 function
of selected depth of materials at 0.5 mm, 2.0 mm and 4.0 mm. Data were analyzed by either one-way
ANOVA 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 all
groups in flexural and compressive strength. The depth of cure decreased as the thickness of both bulkfill
composites increased. In conclusion, SonicFill™ showed favorable mechanical properties compared
to other composites tested. In both bulk-filled groups, microhardness value decreased as the thickness
of the composite increased. The polymerization of the bulk-filled composites was effective only at 2 mm
or less.