Enamel elemental composition

The Biomineralization section begins with a summary of the current state of research on bone, dentin and enamel phosphates, a topic that crosses disciplines that include mineralogical, medical, and dental research. The following two chapters treat the stable isotope and trace element compositions of modern and fossil biogenic phosphates, with applications to paleontology, paleoclimatology, and paleoecology. 

Table A3.2 Major Elemental Composition of Surface and Bulk Dental Enamel ...

Table A3.4 Significant Differences in Trace Element Composition of Whole Human Enamel for High and Low Caries Populationst...

Curzon, M.E.J. and Losee, F.L. (1977) Dental caries and trace element composition of whole human enamel Eastern United States. J. Amer. Dental Assoc., 94, 1146-1150. 

From a materials perspective there are two possible reasons why dental enamel shows the large variations in mechanical properties shown in figure 1 firstly, chemical variations in apatite composition and, secondly, changes in enamel structure with position from the occlusal surface to the EDJ. The chemical composition of enamel can be examined with a lateral resolution of 1-10 pm with electron microprobe analysis. Enamel structure can be obtained with SEM. To perform an accurate microprobe analysis, natural and synthetic minerals are used as standards to calibrate the instrument. This is fairly routine for geologists and earth scientists who are able to obtain chemical compositions with an accuracy of <0.1% for a wide range of elements simultaneously (including Na, Mg, Al, Si, P, K, Ca, Ti, Cr, Mn, Fe, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb, Hf, Ta, Pb, Th, U, F and Cl). In enamel only a few of these (Na, Mg, Al, P, K, Ca, Ti, Cl and F) are above the detection limit. The Ti is likely to be an impurity or contaminant rather than a constituent of enamel. This technique does not work for lighter elements such as C, S, O and N which may be present in enamel. 

Lakomaa. E.-L (1980). Use of NAA in the determination of elements in human cerebrospinal fluid, in Trace Element Analytical Chemistry in Medicine and Biology. Braatter, P. and Schramel, P., Ed., Walter de Gruyter Co., New York, p.97 Lakomaa, E.-L and Rytomaa, I. (1977). Mineral composition of enamel and dentin of primary and permanent teeth in Finland, Scand. J. Dent. Res. 85,89-95 Langmyhr, F.J., Lind, T. and Jonsen, J. (1975). Atomic absorption spectrometric determination of manganese, silver and zinc in dental material by atomization directly from the solid state. Anal. Chim. Acta 80, 297-301... 

Tooth enamel is Ca5(P04)3(0H). Calculate the percent composition of the elements present. 

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