The distribution of lead in human enamel

THE studies which have been made on the occurrence of lead in normal teeth suggest that this element is consistently present in small amounts.'-7 The normal level for whole ashed teeth has been reported to be in the range of 20 to 70 ppm.3 4 Dentin appears to contain approximately 3 times more lead than enamel.3 There have been no studies on the. presence of lead in unerupted teeth or on uptake of lead by teeth. Therefore, it is not known to what extent lead found in teeth has been incorporated during tooth formation or deposited after eruption. The fact that concentrations of lead above normal have been found in the teeth of persons suffering from lead poisoning " 3, 7, 8, 9, 10 demon-strates a posteruptive uptake. Lead determinations in normal teeth of different ages also suggest a posteruptive gain up to the age of about 20, when a fairly constant concentration is reached.3 4 A similar condition apparently exists with regard to lead in bone, in that there appears to be no definite increase with age after a state of equilibrium has been reached between uptake and loss." The significance of the presence of lead in teeth has not been established