Abstract
Flexural properties, machinability, radiopacity, filler composition and geometry of four dual-cure composites for foundation restoration, Built it FR, DCA-300, Unifil Core and Clearfil DC Core, were examined. Flexural properties varied with polymerization modes ; the properties obtained by only chemical without light activation of three products were inferior to those obtained by light activation, while the other demonstrated that the properties obtained by only chemical activation were almost identical to those obtained by light activation. The flexural strength of evaluated composites was smaller than that of dentin, however, the flexural moduli of the three products were similar to that of dentin. All composites showed greater machinability and opacity than dentin. Composite and dentin were easily distinguished in radiographic image. Each oomposite contains different types and sizes of filler by scanning electron microscope investigation. The radiopacity of composite was mainly due to Ba or Sr.
