Trace element distribution in human teeth by x-ray fluorescence   spectrometry and multivariate statistical analysis
  X-ray fluorescence spectrometry (XRFS) was used as a multielement method of evaluation of individual whole human tooth or tooth tissues for their amounts of trace elements. Measurements were carried out on human enamel, dentine, and dental cementum, and some differences in tooth matrix composition were noted. In addition, the elemental concentrations determined in teeth from subjects of different ages, nutritional states, professions and gender, living under various environmental conditions and dietary habits, were included in a comparison by multivariate statistical analysis (MVSA) methods. By factor analysis it was established that inorganic components of human teeth varied consistently with their source in the tissue, with more in such tissue from females than in that from males, and more in tooth incisor than in tooth molar. 
Cristiana Oprea, Pavel J. Szalanski, Marina V. Gustova, Ioan A. Oprea,   Violeta L. Buzguta
physics.med-ph