RESUMEN
OBJECTIVES: To compare the cytotoxicity of conventional GIC and Resin Modified GIC (RMGIC) polymerized at 2 different times on stem cells from human exfoliated deciduous teeth (SHED). STUDY DESIGN: The conventional GIC (Fuji IX GP Extra) and RMGIC (Fuji II LC) were mixed and incubated in a prepared Dublecco's Modified Eagle Medium (DMEM) for seven days. After seeding the characterized SHED for 24 hrs, six replicates of seven serially diluted extracts of each group were added and incubated for 72 hrs. MTT test was used for cytotoxicity evaluation and the data were analysed using Kruskal-Wallis followed by Mann-Whitney test, with the statistical significance set at P<0.05. RESULTS: The half maximal inhibitory concentration (IC50) was found at 45.0 mg/ml, 45.0 mg/ml and 31.25 mg/ml for Fuji IX, Fuji II LC (40s) and Fuji II LC (20s), respectively. Significantly different cytotoxic effects were found between Fuji II LC polymerized at 20 secs and 40 secs, and between Fuji IX and Fuji II LC (20s) (P<0.05), and these were observed in all concentrations except for 50 mg/ml. CONCLUSIONS: RMGIC polymerized at 20 secs exhibited the least favorable cell viability among all groups. Nevertheless, the cell viability was comparable to conventional GICs when the manufacturer's recommended time was doubled (40 secs).