Heavy metals in human primary teeth: some factors influencing the metal concentrations

Human primary teeth have been used as indicators of heavy metal exposure fo r several decades, but the knowledge about the influence of factors such as tooth type and the presence of caries and roots on metal concentrations is limited. Samples of tooth powder from more than 1200 Norwegian primary tee th without fillings have been analyzed for lead, zinc and cadmium content, and 554 of them for mercury. The material represents all groups of tooth ty pes (incisors, canines and molars), carious and non-carious teeth, and teet h with and without roots. Here we investigate how tooth group and the prese nce of caries and roots are related to metal concentrations in the teeth. W e find that carious teeth have higher metal concentrations than non-carious teeth; the difference was statistically significant for lead, mercury and zinc. Teeth with roots have higher lead and zinc concentrations than teeth without roots. We find differences in metal concentrations between the toot h groups for lead, mercury and zinc. Significant, positive correlations are found between lead and the three other metals and between mercury and zinc . We conclude that metal concentrations in primary teeth are affected by th e presence of caries and roots and by tooth group. (C) 2000 Elsevier Scienc e B.V. All rights reserved.