APPLICATION OF FLOW-CYTOMETRY TO DETERMINE THE CYTOTOXICITY OF URETHANE DIMETHACRYLATE IN HUMAN-CELLS

The effects of an oligomer, urethane dimethacrylate (UDMA), on two hum an cell lines were studied using flow cytometry (FCM). Untreated and t reated cultures of propidium iodine-stained KB (epidermal oral carcino ma cells) and human foreskin fibroblast (HFF) cells were analyzed for cellular DNA content. Concentrations of 10 and 25 mu M of UDMA slightl y perturbed the KB cell cycle progression at 24 and 48 h of incubation . However, the effect of 50 mu M was more pronounced at the latter inc ubation time period. In cell growth experiments, the sublethal concent rations (10 and 25 mu M) produced inhibition of KB cell growth rate at a moderate level which resulted in the prolongation of cell populatio n doubling time. Significant inhibition of cell growth occurred when 5 0 mu M (lethal concentration) was used. Data obtained from the cell, c ycle perturbation analysis, evidenced by FCM, correlated with the exte nt of inhibition in KB cell growth rates. The effects of sublethal con centrations were reversible during a 24 h period of oligomer withdrawa l from culture medium. In contrast, the effects of 50 mu M were not re versible. In HFF cells the depletion of S phase in the cell cycle was the major effect of 50 mu M of UDMA. It was concluded that FCM technol ogy is an ideal and practical approach for studying the cytotoxicity o f components of dental composites. (C) 1994 John Wiley and Sons, Inc.