Metal release from heat-treated orthodontic archwires.
Stainless steel and cobalt-chromium orthodontic archwires were subjected to an immersion corrosion test. Wires in the as-received state and wires subjected to a 1-min heat treatment at different temperatures were tested. Iron from the stainless steel and cobalt from the cobalt-chromium product were analyzed in artificial saliva after 1 week of immersion. Both products were analyzed for nickel. The results showed that the cobalt-chromium wire in the as-received state released more metals than the stainless steel. The metal release from the stainless steel wire increased rapidly when subjected to 400 degrees C or higher. For the cobalt-chromium product the increase started at about 500 degrees C. At temperatures above 500 degrees C the release of metals was 15 to 60 times higher than the lowest values. The present results should be considered in procedures involving application of heat to orthodontic wires.
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002858:Chromium Alloys / Q000032:analysis; D003035:Cobalt / Q000032:analysis; D003343:Corrosion; D006358:Hot Temperature; D007501:Iron / Q000032:analysis; D008422:Materials Testing; D009532:Nickel / Q000032:analysis; D009967:Orthodontic Appliances; D009969:Orthodontic Wires; D012995:Solubility; D013193:Stainless Steel / Q000032:analysis
D002858:Chromium Alloys; D013193:Stainless Steel; D003035:Cobalt; D009532:Nickel; D007501:Iron