Release of cobalt from cobalt chromium alloy constructions in the oral cavity of man.

The release of cobalt from a cobalt chromium alloy construction with a major palatal connector (palatal strap) in the maxilla was determined for 10 test subjects. The concentration of cobalt in unstimulated whole saliva and tongue scrapings was estimated 21, 14 and 7 d respectively before and 1, 2, 3, 10, 20 and 30 d after insertion of the cobalt chromium alloy construction. The method used to quantify the cobalt content was flameless atomic absorption spectrophotometry (AAS). The results showed that the median cobalt concentration in saliva and tongue scrapings increased after the insertion of the cobalt chromium alloy construction, with the highest values occurring in the first 2 d after insertion. The tongue scrapings, in general, showed higher cobalt median values than saliva did at all times of estimation. The sampling method described in the present study seems to be useful in long-term investigations in man, where numerous sample collections in the oral cavity are required in order to determine metal content. The risk of negative biologic effects on the human organism caused by the cobalt release from the alloy is discussed.