Biological cobalt/chromium alloys

The need to develop new materials for artificial hip joints is driven, in part, by the local and systemic biological consequences of wear debris arising from the currently used materials. As a result, most studies of artificial joint materials, such as alumina, cobalt-chromium-molybdenum alloys (CoCrMo), and ultrahigh molecular weight polyethylene (UHMWPE), concentrate on wear analyses, most reliably carried out with a hip-joint simulator and involving wear-... 

ANSI/ADA specification no. 14 provides a requirement for removable partial dentures of a combined minimum of 85% by weight of chromium, cobalt, and nickel or, for alloys failing to meet that minimum, at least 20% chromium. Bio-compatibiUty is demonstrated by passing the pertinent criteria of ANSI/ADA specification no. 41, Recommended Standard Practices for Biological Evaluation of Dental Materials. 

Chromium-cobalt alloys are being increasingly used in medical implants, and metal-on-metal hip resurfacing arthroplasty can cause the release of large amounts of very small wear particles and metal ions [21 ]. The long-term biological consequences of exposure to these clu-omium-cobalt particles are largely unknown. 

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