ABSTRACT
BACKGROUND: There have been no reports in CNKI database addressing the cellular apoptosis caused by stainless steel materials used in the dental magnetic attachment. OBJECTIVE: To observe the effects of 3 stainless steel materials used in the dental magnetic attachment, cobalt-chromium alloy, titanium alloy, and austenitic stainless steel on L-929 cell apoptosis. DESIGN, TIME AND SETTING: A comparative observation was performed at the Central Laboratory of China Medical University between June and December 2007. MATERIALS: Mouse L-929 fibroblasts in logarithmic growth phase were provided by Institute of Tumor, First Affiliated Hospital of China Medical University, China. Cobalt-chromium (Co-Cr) alloy was purchased from Heraeus-Kulzer Corporation, China. Titanium alloy was obtained from Morita Company, Japan. Austenitio stainless steel was provided by Institute of Mental Research Chinese Academy of Sciences, China. METHODS: The leaching liquor of Co-Cr alloy, titanium alloy, and austenitic stainless steel was made by culturing 3 kinds of round-slice mental materials in 24-well plate with RPMI-1640 medium at 0.1 mL/cm2 (leaching liquor volume: specimen surface area). L-929 fibroblasts were divided into 5 groups: Co-Cr alloy, titanium alloy, austenitic stainless steel, negative control, and positive control. The Co-Cr alloy, titanium alloy, and austenitic stainless steel groups were cultured with corresponding leaching liquor (250, 500, and 1 000 g/L). Cells from the negative control and positive control groups were cultured with simple RPMI 1640 medium and 100 mg/L mitomycin-treated L-929 cells. MAIN OUTCOME MEASURES: Following 24-hour culture, the effects of 3 kinds of leaching liquor (at different concentrations) on L-929 fibroblasts were examined through the use of flow cytometer. RESULTS: There was significant difference in cellular apoptosis between Co-Cr alloy, titanium alloy, and austenitic stainless steel groups at the same concentration or between different concentrations for the same dental material (P < 0.01), but no significant difference existed between titanium-alloy (250 g/L) and negative control groups (P > 0.05). CONCLUSION: Co-Cr alloy, titanium alloy, and austenitic stainless steel have apparent influence on cellular apoptosis. The apoptosis rate is the greatest in the Co-Cr alloy group, followed by austenitic stainless steel group, and lastly titanium alloy group.