Abstract
In the present study I examined conditions of dynamic extraction for cytotoxicity evaluation of metallic biomaterials. Specimens of Ni-Cr alloy, Co-Cr alloy and Ti of three shapes were extracted in glass vessels under dynamic conditions at 160, 200, or 240 rpm. Ni-Cr and Co-Cr alloy, but not Ti, specimens showed cytotoxicity, which varied with specimen shape and extraction conditions. Cylindrically shaped specimens showed greater dissolution of Ni, Cr and Co and greater cytotoxicity than spherical or plate-shaped specimens. Dissolution of the constituent elements and cytotoxicity also increased with extraction speed and duration. Furthermore, concurrent analysis of wear debris revealed that the extraction condition of 240 rpm for 7 or 14 days resulted in unexpected wear of the glass vessel and is therefore not appropriate for these base metals. The most efficient extraction condition for in vitro cytotoxicity evaluation of base metals was found to be that in which a cylindrically-shaped specimen is extracted at 240 rpm for 5 days. It is considered that the present results offer potential in validation of in vitro testing of metallic biomaterials.
