Résumé
<p><b>OBJECTIVE</b>To choose the best retraction agent for the clinic by evaluating cytotoxic effects of six chemical retraction agents on human gingival fibroblasts (HGF) in vitro.</p><p><b>METHODS</b>HGF were treated with six chemical retraction agents which included 20% Al2(SO4)3, 5% Al2(SO4)3, 15.5% Fe2(SO4)3, 13.3% Fe2(SO4)3, 0.1% HCl-epinephrine and 0.01% HCl-epinephrine. The damage of direct contact and proliferation inhibit were observed by methyl thiazolyl tetrazolium (MTT) colorimetric assay, the ultra structure was observed under transmission electron microscope (TEM).</p><p><b>RESULTS</b>All of chemical retraction agents caused cell damage and proliferation inhibit. The ability of cytotoxic effect increased in an order of 0.01% HCl-epinephrine<0.1% HCl-epinephrine<5% Al2(SO4)3<20% Al2(SO4)3<Fe2(SO4)3. There was no statistically significant difference between 13.3% Fe2(SO4)3 group and 15.5% Fe2(SO4)3 group. At HCl-epinephrine group and 5% Al2(SO4)3 group, the number of organelles were decreased, mitochondria and endoplasmic reticulum were swollen. At 20% Al2(SO4)3 group, organelles swelling and decreased number of organelles became more severe, the nuclear chromatin was unevenly distributed. Cell degeneration could be made by Fe2(SO4)3.</p><p><b>CONCLUSION</b>0.01% HCl-epinephrine was the least toxic gingival retraction agents, 13.3% Fe2(SO4)3 and 15.5% Fe2(SO4)3 are found to have the strongest cytotoxic effect on cell cultures.</p>