The Factors of Cytotoxicity of Amalgams

Abstract

The effect of amalgam composition and aging time on the cytotoxicity of dental amalgams was examined by means of a rapid and sensitive in vitro cell culture test.Amalgam disks(4mm dia.×1mm thick)were made at 14MPa and aged for 1 hour, 24 hours, 7 days and 30 days at 37℃.Each aged amalgam disk(n=8)was placed on a cover glass in a plastic dish.Five ml of fibroblasts, 1×10⁵par ml of Eagle's MEM with 10% fetal calf serum, were evenly seeded and incubated for 24 hour at 37℃ in a humidified atomosphere of a 5% CO₂ in air.The cover glass was removed and fixed in 10% neutral formalin and then stained by H.E.to differentiate between the areas affected or unaffected cells around the specimens.The affected area was quantitatively determined using an image analysis system.Dispersalloy(zinc-containing high-copper amalgam)showed higher cytotoxicity than any other amalgam.Lumi Alloy(high-copper amalgam)showed the same cytotoxicity as Hi-Atomic M(low-copper amalgam).Spherical-D showed the least cytotoxicity among the tested amalgams.The cytotoxicity of amalgam was decreased with aging time, probably because surface is oxidized or because the release of the elements such as zinc most responsible for the cytotoxicity, is prevented by further amalgamation.