Determination of some trace elements in human tooth enamel

Determination of seven elements (Cu, Fe, Mg, Mn, Pb, Sr and Zn) in whole en amel and surface layers of extracted non-carious human teeth by FAAS, ETA A AS, ICP-AES and ICP-MS (Pb) is demonstrated. Techniques are described for o btaining whole enamel and its acid dissolution. Fifty mu m width enamel lay ers from outer enamel surface to a 200 mu m depth were successively etched in 1 mL of 3 M HClO4 for 3 min dissolution periods. Enamel samples were ana lyzed for populations under and over 20 years of age and enamel from Bronze Age teeth. Concentrations of microelements in the whole enamel and in the first surface layer (50 mu m depth) were compared. With exception of Sr and Mg, all elements show significantly higher concentrations in the first lay er than in whole enamel and higher concentration in teeth of individuals ov er 20 years, which demonstrate the cumulative effect of these elements. The Cu, Fe, Mn, Pb and Zn concentrations in four layers of erupted and non-eru pted teeth decreased while Mg and Sr concentrations increased toward enamel -dentine junction. The concentrations of most elements were almost constant as they approached the 150 mu m layer. This concentration gradient may res ult from interaction between saliva and teeth and supports the hypothesis t hat the surface de- and re-mineralization process is effective at most to 1 50 mu m from the enamel surface.