RESUMO
EDTA-T and 10 per cent citric acid used as root canal irrigants lead to more visible dentinal tubules than 5 per cent sodium hypochlorite associated with 3 per cent hydrogen peroxide. However, these cleansing agents must be compatible with apical periodontal tissue. We analyzed the cytotoxicity of 10 per cent citric acid and EDTA-T in cultured fibroblasts using Trypan blue. The solutions were diluted to 1 per cent, and 0.01 percent and applied to NIH 3T3 cell cultures. Cells grown on fresh DMEM served as a control. After 0, 6, 12, and 24h (short-term assay, viability) and 1, 3, 5, and 7 days (long-term assay, survival), the cells were counted using a hemocytometer. In short-term test, cell viability ranged from 85 per cent to 99 per cent for all experimental groups with no statistical differences when compared with control cultures, except for the group treated with 1 per cent EDTA-T, which caused a progressive decrease in cell viability. In long-term test, all cultures increased in number from day 1 to the end of the experimental period, showing no inhibition of cell proliferation, except for the cultures treated with 1 per cent EDTA-T, which totally prevented cell growth. All dilutions of 10 per cent citric acid were more biocompatible than EDTA-T. Cultures treated with citric acid had a higher percentage of viable cells in the short-term assays, and the cells retained their self-renewal capacity
