The association of tooth lead content with dental health factors

The purpose of this study was to determine the relationships of lead content in the human tooth with the prevalence of caries, dental plaque, pH of saliva, levels of Salivalis lactobacilli (SL) and Mutans streptococci (MS), degree of dental abrasion, tooth colour and toothbrushing frequency. A total of 220 teeth (one per person) were analysed using a microwave oven digestion procedure and lead content was measured by atomic absorption spectrometry. Tooth lead content followed a logarithmic-normal distribution and it increased with the prevalence of caries. Tooth lead concentrations were positively correlated with all the considered dental health factors except the pH of saliva, for which there was a significant negative correlation. Coloured teeth and teeth subject to abrasion showed the highest lead content. The highest number of colonies of SL and MS in saliva paralleled the highest lead tooth levels. Teeth obtained from irregular brushers presented higher tooth lead contents than subjects with a regular toothbrushing frequency. Multiple logistic regression analysis showed a significant association between tooth lead levels and dental plaque surface, Salivalis lactobacilli number, dental abrasion and dental colour. We conclude that accumulation of lead in teeth is associated with those dental health factors.