EFFECT OF NICKEL-BASED DENTAL CASTING ALLOYS ON FIBROBLAST METABOLISMAND ULTRASTRUCTURAL ORGANIZATION

Previous cell culture evaluations have shown that nickel-chromium dent al alloys did not affect cellular viability or morphology. However, ni ckel-based alloys released corrosion products which decreased cellular proliferation. It was hypothesized that this decrease was due to an i nterference of cellular energy metabolism by released metal ions. To t est this hypothesis, we evaluated the effects on cellular energy metab olism, adenosine triphosphate (ATP) levels, and cellular ultrastructur e by four nickel-based alloys, including high and low chromium alloys with and without beryllium additions, in human gingival fibroblast cel l cultures. Energy metabolism was evaluated by measuring glucose-6-pho sphate dehydrogenase (G-6-PDH) activity. ATP levels were measured with the luciferin-luciferase method. Cellular membranes and ultrastructur al organization were evaluated by scanning and transmission electron m icroscopy. The results of this study showed that metal ions released f rom all alloys completely inhibited G-6-PDH activity and reduced cellu lar ATP levels as compared to controls. The reduction in intracellular ATP was greater for the beryllium containing alloys than the non-bery llium-containing alloys. However, no morphologic changes in cellular m embranes or organelles were observed. These results support the hypoth esis that metal ions released from nickel-based dental casting alloys interfere with cellular energy metabolism. (C) 1995 John Wiley and Son s, Inc.