Migration of mercury from dental amalgam through human teeth
Harris HH, Vogt S, Eastgate H, Legnini DG, Hornberger B, Cai Z, Lai B, Lay PA.
School of Chemistry, The
University of Sydney, NSW 2006, Australia.
J Synchrotron Radiat. 2008 Mar;15(Pt 2):123-8.
Exposure to mercury from
dental amalgams, with possible negative
health effects, has generally been considered to occur via either
erosion or evaporation directly from the surface of fillings,
followed by ingestion.
The aim of this study was
to determine the relative importance of the direct migration of mercury through
the tooth as an alternative exposure pathway. X-ray fluorescence imaging has
been used to determine quantitatively the spatial distribution of Hg, Ca, Zn
and Cu in sections of human teeth that had been filled
with amalgam for more than 20 years.
X-ray absorption near-edge spectroscopy (XANES) was also employed to gain chemical information on the mercury present in the teeth. Hg (up to approximately 10 mg g(-1)) and Zn (>100 mg g(-1)) were detected in the teeth several millimetres from the location of the amalgams. At high resolution, Hg showed higher concentrations in dentinal tubules while Zn was generally evenly distributed. XANES showed that the chemical form of Hg that had migrated into the tooth had been altered from that present in the amalgam. The differing spatial distributions of Hg and Zn suggest distinct transport mechanisms for the two metals, presumably chemical for Zn and initially physical for Hg. Subsequent oxidation of Hg may lead to a loss of mobility or the development of a secondary transport mechanism. Most importantly the detection of Hg in areas of the tooth that once contained an active bloodstream and in calculus indicates that both exposure pathways should be considered as significant.
Dies hatten Till und Talabani 1985 erstmals nachgewiesen und die hohen Hg-Werte im Zahn und der Wurzel!