Cytotoxic and inflammatory response of human lung epithelial cells A549 to particles released from dental restorative materials during dry and wet grinding.

Abstract

The aim was to evaluate the release of particles from dental materials during wet and dry grinding and test their effects on human lung epithelia cells in-vitro. Four dental restorative materials were used: two composites [Ceram.x® universal (Dentsply Sirona) and Filtek™ Supreme XTE (3M)], one ceramic [VITABLOCS® Mark II (VITAy)] and a ceramic-resin material [Lava™ Ultimate (3M)]. Material samples were ground to powder under standardized wet and dry conditions in an isolated dental room. During grinding, the particle concentrations were measured with LAS and CPC. Baseline values were measured before grinding. The particles' size was evaluated using DLS and SEM. Water was used as control. The cytotoxicity and inflammatory response of the lung cells (A549) after exposure to different concentrations (1, 3, 10, 30, 100, 300μg/mL) of the generated dust were analyzed with LDH, WST-1 and ELISA. LAS and CPC revealed a high concentration of particles<10µm and<1µm respectively, into the air. Particles showed high tendency to agglomerate. DLS showed particle size distribution between 150nm and 18µm independently of the material composition. All materials induced significant effects (p<0.05) on the cell membrane integrity and viability of the A549 cells. Only the ceramic particles showed a significant increase in hydroxyl radical formation at low concentrations (p<0.05), for both wet and dry conditions. All materials except ceramic, induced a significant release of IL-8 in A549 cells at 300μg / mL (p<0.05). Wet and dry grinding of dental materials result in release of ultrafine and fine particulate matter into the air. The in-vitro findings on the cellular response of lung cells to generated dust indicate a potential risk for human health due inhalation of the released particles. The use of water-cooling seems to be beneficial resulting in reduced release of particles compared to dry grinding.