Gjerdet N R, Herø H
Department of Dental Materials, School of Dentistry, University of Bergen, Norway.
Acta Odontol Scand. 1987 Dec;45(6):409-14. doi: 10.3109/00016358709096365.
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.
