CORROSION AND CELL-CULTURE EVALUATIONS OF NICKEL-CHROMIUM DENTAL CASTING ALLOYS

In this study, the corrosion and surface properties of four commercial ly available nickel-chromium dental casting alloys, were evaluated usi ng electrochemical corrosion testing and Auger electron microscopy. Th e corrosion tests were conducted under cell culture conditions of 5% C O2 humidified atmosphere at 37 degrees C in minimum essential medium ( MEM) balanced salt solution, 95% MEM-5% FBS (fetal bovine serum) cell culture media, and in 95% MEM-5% FBS media after cold solution sterili zation of test samples. The results of the surface and corrosion analy ses were correlated to cytotoxicity and metal ion release from the all oys using agarose overlay and direct contact cell culture tests. The s urface and electrochemical corrosion analyses demonstrated that the no n-beryllium containing alloys were more resistant to accelerated corro sion processes as compared to the beryllium-containing alloys. All all oys demonstrated decreased corrosion rates in cell culture solutions a fter cold solution sterilization treatment. The corrosion products rel eased from the nickel-based alloys failed to alter the cellular morpho logy and viability of human gingival fibroblasts, however they did cau se reductions in cellular proliferation. The potential for accelerated corrosion and the exposure of local and systemic tissues to elevated levels of corrosion products raises concerns over the biocompatibility of these alloys. (C) 1994 John Wiley & Sons, Inc.