Mercury Release From A Sn-Cu-Zn Free Amalgam

Abstract

Abstract-The mercury controversy related to dental amalgam is still continuing.In Malaysia, part of, this controversy has been attributed to a recently -introduced dental amalgam claimed to be non-mercury releasing and causing no mercury toxicity. The purpose of this study was to investigate whether this amalgam, Composil, was indeed non-mercury releasing.Six specimens each ofComposil and a control (GS-80) were incubated at 3TC in deionised-distilled water. The daily mercury release was determined over a four-week study period using the stationary cold-vapour atomic absorption spectrometric method. The mean mercury release of Composil was 30.9 Ilg/cm 2 / 24hr whilst that of GS-80 was 0.9 Ilg/cm 2 124hr and the difference was found to be highly significant (P < 0.00l).Results of this study therefore did not substantiate the manufacturer's claim. The release of mercury from amalgam restorations and their implications in clinical practice were also discussed. IntroductionRecently, a tin, copper and zinc free amalgam alloy comprising of only silver and mercury was introduced to the dental profession in Malaysia. Amongst the list of claimed superior physical and mechanical properties was the claim that it gave 'no mercury toxicity' as it was a non-mercury releasing material. The manufacturer attributed this to the 'highly reactive silver' which would instantly 'freeze mercury' thereby resulting in an amalgam that did not contain any unreacted free mercury. It was even claimed that burnishing could be carried out without fear of sur facing out any mercury.A non-mercury releasing amalgam will have significant implications for the dental profession as dental amalgams are still popularly and widely used for the restoration of posterior teeth. More recently, there has again been increased professional and public concern over mercury relea<;e from~unal-gams (1) because of tlle long recognised toxic potential of I