Cell viability of fine powders in hybrid resins and ceramic materials for CAD/CAM.

Resin blocks and ceramic blocks for CAD/CAM crowns were cut into powders and separated into three particle size groups. Oxidative stress and cell viability were measured in 3T3 and FRSK cells. The results of cytotoxicity tended to be slightly higher for resin than for ceramics. The values also increased as the particle size decreased in the powders. In addition, incorporation into cells was frequently observed under SEM, suggesting that the particle size of easily incorporated dust is different among cell types. Fluorescence-activated cell sorter (FACS) showed an increase in apoptosis and a decrease in cell viability in most of the sample groups compared to the control group. Hematoxylin and eosin staining of the cells showed deep staining of the nuclei in the sample groups. It was found that oxidative stress cell viability and apoptosis appeared differently depending on the size of the particles and the type of cells.