To study the cytotoxicity of dental amalgam alloys, a cell culture system with L strain fibroblasts was used, and certain amount of cells were cultivated in the culture well containing seven kinds of amalgam specimens which had been obtained immediately, 24 hours, and 48 hours after trituration.
On day 2, 4, and 7 of cultivation, the cells were harvested using 0.25% trypsin and counted after staining with 0.3% trypan blue. The number of viable cells was assessed by calculating the relative growth rate compared with the normal control group. Also, the changes in the shape of the cells which had contacted with the amalgam specimens were examined with a phase-contrast microscope.
The results were as follow
1. Low-copper, lathe-cut amalgams ("C", "D") showed a highest cell multiplication rate corn-pared to the other amalgams, and in the early cultivation time, thecells contacting the specmens were degenerated, but with the lapse of the cultivation time, the cells were recovered.
2. Low copper, lathe-cut amalgams ("C `ID") showed a higher cytotoxicity in the specimen immediately after trituration than at 24 hours after trituration.
3. Amalgams containing zinc ("B", "F") and high copper amalgams ("A", , "G") showed a rapid decrease in viable cells, and the surviving cells did not recover with the lapse of the cultivarion time.
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