Proton-induced X-ray emission analysis of Zn, Sr and Pb in human deciduous tooth enamel and its relationship to dental caries scores.

The absolute concentrations of these elements were obtained by calibration with the animal-bone standard of the International Atomic Energy Agency. From exfoliated deciduous incisors and canines of 193 6- and 9-year-old children living in four Finnish towns, 77 enamel samples from subjects with low and high caries (dmfs = 0 and greater than 6, respectively) were analysed. There were no statistically significant correlations between Zn and caries, or Pb and caries, but a weak positive correlation existed between Sr and caries (r = 0.341; p less than 0.001). The lead concentration in incisors (8.1 +/- 5.3 parts/10(6)) was twice as high as in canines (4.1 +/- 2.6 parts/10(6)), whereas the Sr concentration was lower (63 +/- 18 and 85 +/- 13 parts/10(6), respectively) emphasizing the importance of relating such analysis to the tooth type.