[A study of trace elements in deciduous teeth. The differences of Cd, Zn, Pb, and levels in prenatally and postnatally formed deciduous teeth].

It has been reported by some investigators that deciduous teeth could be useful materials for the analysis of the trace elements available to the human body burden. In this study, an attempt was made to define that uptake of trace elements (Cd, Zn, Pb and Cu) take place during formation of the deciduous tooth. Samples were prepared from exfoliated human upper deciduous central incisors divided into two or three sections at incremental lines includes neonatal line. Samples were dissolved with nitric acid and dried at 80 degrees C. Each element was separated chromatographically using acetone-HCl gradient solution with a cation exchange resin and then analyzed by flameless atomic absorption spectrophotometry. The results were as follows: 1. Ca, P, Ca/P ratio levels showed no significant differences between prenatally and postnatally formed teeth. 2. In the enamel, (1) Cd level showed a tendency to be higher in the postnatally formed enamel, but not significant. (2) Zn and Pb levels were found to be significantly higher in the postnatally formed than in the prenatally formed enamel. (3) Cu level was reversed significantly. 3. In the dentin, (1) Cd and Cu levels in the postnatally formed dentin I were significantly less than prenatally formed denin, and these were almost equal to the postnatally formed dentin II. (2) Zn level in the postnatally formed dentin I was almost equal to the prenatally formed dentin, but that was significantly less than the postnatally formed dentin II. (3) Pb level in the postnatally formed dentin I was significantly less than the prenatally formed dentin and the postnatally formed dentin II. Therefore, the results suggest that the accumulation of Cd and Cu to the deciduous tooth mainly occur in the prenatal and the accumulation of Zn and Pb to the deciduous tooth occur not only in the prenatal but also continuously in the postnatal, and the deciduous tooth can be a useful materials for environmental contamination recorder.