Scanning electron microscopy (SEM) and energy-dispersive x-ray spectrometer (EDS) were used to examine the effect of filler morphology and composition on CP-OCT imaging of the resin-based dental composites. Several composite discs were selected and polished with sandpaper sheets (SiC, P240, P600, P1200), followed by fine polishing with alumina suspensions (1- and 0.05-μm, respectively) in order to remove the resin rich layer that can confound elemental analysis. Then the specimens were ultrasonicated in distilled water for 5 min and air-dried. The polished discs mounted on aluminum stubs were examined by an EDS (Quantax 70, Bruker, Germany), which was attached to the SEM (TM3000, Hitachi, Japan) to verify the chemical composition of the restorative composites. The accelerating voltage was 15 kV, and, in order to avoid the influence on composition analysis, conductive coatings on polished discs were not applied. High-resolution images of these composites were then taken using a Field Emission SEM (Joel 6500, Japan) at an accelerating voltage of 5 kV and a working distance of 10 mm. For SEM, the polished specimens were sputter-coated with 5 nm of platinum to improve the resolution and mounted on aluminum stubs with carbon tape.