RESUMO
AIM: To compare the cytotoxicity of materials used to repair perforations using permanent V79 fibroblasts and murine granulocyte-macrophage progenitor cells (CFU-GM). METHODOLOGY: Set specimens from amalgam, glass-ionomer, SuperEBA, N-Rickert, MTA and gutta-percha were eluted with culture medium for 72 h and their cytotoxicities were assessed by incubating the extracts with V79 and bone marrow-derived progenitors for 24 h and 7 days, respectively. Cytotoxicity on V79 cells was judged using the total nucleic acid content (NAC), neutral red uptake (NRU) and reduction of the tetrazolium salt (MTT). The number of bone marrow CFU-GM colonies determined in clonal cultures stimulated with recombinant murine granulocyte-macrophage colony-stimulating factor was used to assess cytotoxicity to progenitor cells. Statistical analyses were conducted using the one-way analysis of variance and Tukey's test where appropriate. RESULTS: All materials were cytotoxic in both cell systems; however, CFU-GM was more sensitive to the extracts than V79 cells. A similar rank order of toxicity was observed in V79 cells using the NAC and the MTT assays: glass-ionomer > N-Rickert congruent with SuperEBA > gutta-percha > amalgam congruent with MTA (P < 0.05). In contrast, the NRU test exhibited a lower sensitivity to MTA, gutta-percha and amalgam extracts. In the clonal culture assay, the toxicity was less pronounced in the presence of gutta-percha, SuperEBA and MTA. Similar cellular responses were found by placing the set specimens directly in the clonal culture dishes. CONCLUSIONS: The sensitivity of toxicity depended on the choice of the endpoint and the cell-culture system. Nevertheless, MTA was ranked as the least cytotoxic cement in both cell systems.