A Study on Cytotoxicity of Two Kinds of Stainless Steel Used in Dental Magnetic Attachment

Objective To investigate the biosafeness of two kinds of special stainless steel materials that will be used in the magnetic retainer in order to evaluate their biocompatibility for clinical application. Methods After mixing the extracting liquid with the L - 929 cells, we evaluated the cytotoxicity of those materials by cell morphological observation and Mil-assay, comparing them with pure titanium and cobalt-chrome alloy. Results The cell morphological observation indicated that with cultivate time increasing, in the positive control, the cells of shedding off or dead cells increased gradually. The cells of the rest groups almost grew while attaching to the plate continuously, and the cell density increased. The result of MTT-assay indicated S, stainless steel and 82 stainless steel showed slight cytotoxicity (the RGR decreased by 3%), Cobalt-Chrome alloy showed class I cytotoxicity (the RGR decreased by 11 % ) . But the statistical analysis result manifested there were not significant differences in the optical densities between metal material groups and the negative control ( P 0.05). Conclusion The experiment results showed the two kinds of stainless steel (St and 82) only had very faint cytotoxicity, which met the requirement for clinical application. It provided a biological basis for its application in the magnetic attachment.