| Abstract: | Purpose. We examinated the cytotoxicity of metallic dental material eluates on human oral epithelium cells and gingival fibroblasts. Methods. A total of five common metallic alloys, including Amalgam, Gold, Nickel, Titanium, and Platinum were tested. Five discs of each alloy were prepared, and each disc was 15 mm diameter and 2 mm thick. After being autoclaved, these alloy discs were incubated with 5 ml of culture medium at 37?C, with 5% CO<sub>2</sub> for 24 hours. The medium was then used to grow KB and HGF-1 cells. MTT assay examined the cytotoxicity of alloy eluates after 24-hour incubation. The effects of toxic alloy on cell cycle, necrosis, p53 and NF-kB activity, and DNA synthesis were further examined by flow cytometry, lactate dehydrogenase releasing assay, luciferase assay, and BrdU-incorporation, respectively. Results. Morphologic observation and the MTT test revealed that only the amalgam alloy was cytotoxic. Although flow cytometry showed no apoptotic cells after amalgam alloy treatment, high lactate dehydrogenase activity was found in culture medium. These results suggested that amalgam alloy induced breakdown of the cell membrane, a characteristic of necrosis. In addition, elevated p53 and NF-kB activity after amalgam alloy treatment supported that this alloy could cause inflammatory and stress responses. Finally, BrdU incorporation showed that amalgam alloy inhibited DNA synthesis. Conclusions. Based on the results of this experiment, casting metal alloys are safer than amalgam alloy. |
