The quantititive determination of Ca,Na,Al,Mg, and C1 in normal enamel and dentin by neutron activation and high resolution gamma spectrometry.

Introduction I is a well known fact that the ingestion of an optimum amount of lluoride during the developmental period of the crowns of the teeth renders them more resistant to caries. It is possible that other trace elements may also assist in reducing the incidence of the disease: for example, by influencing the solubility of the calci­ fied dental tissues, by producing changes in the morphology of the teeth or by altering the crystallinity of the enamel'. Before the function of various elements in teeth can be fully explained or the changes that occur in their distribution in pathological states can be interpreted, their normal distribution must be deter­ mined. Thus the methods adopted for the quantitative analysis of the elements in teeth arc continually being improved. Of the recently developed techniques, neutron activation analysis, because of its high degree of sensitivity, enables the presence of the major and minor mineral constituents of teeth to be revealed. The principles involved in activation analysis in general and neutron activation analysis in particular were discussed in a recent paper1. The distinctive features of neutron activation analysis may be applied to de­ termine the various elements in biological materials; the inherently high sensitivity of this technique makes it suitable for the detection of mere traces of elements. Previously Nal (Tl) scintillation counters were used and lengthy radio­ chemical separations were-necessary prior to the determination of one or more components in an irradiated sample3. With the development of high resolution