[Dissolution of silver-based alloys under dynamic conditions and its relation to cytotoxicity (in vitro)]

Dissolution of eight silver-based alloys for small casting was investigated under dynamic conditions that accelerated abrasive particle wear. The extract was separated into filtrate and sediment with a 0.22 micron cellulose acetate filter and added to cell culture to study cytotoxicity. Dissolution of silver exhibited the highest dissolution into the extract in the alloys tested. Tin was eluted from six alloys, and indium from five alloys. Following filtration with a 0.22 micron filter, silver, tin and indium were not detected in the filtrate. Zinc was also eluted from all of the alloys, ranging from 5.073 ppm to 29.52 ppm. The amount of zinc in the filtrate was one fifth to tenth of that of the extract. Copper was eluted from two alloys. The amounts of copper in the filtrate and extract were similar. The extract was most cytotoxic, while the filtrate was also cytotoxic except for after one day extraction. The present results demonstrate that extraction under dynamic conditions appears to be useful for investigation of metal corrosion and cytotoxicity in vitro.