Influence of lead on the cariostatic effect of fluoride co-crystallized with sucrose in desalivated rats

Primary teeth microhardness and lead (Pb) levels

Objectives

Lead (Pb) exposure is associated with dental caries. Whether Pb affects tooth microhardness, is unclear. Our objective was to assess whether Pb concentration is associated with microhardness.

Methods

Exfoliated primary teeth were collected from 46 volunteers. Teeth were sectioned, one half of each tooth was tested for enamel Knoop microhardness. The remaining half was digested and Pb measured using an inductively coupled plasma-mass spectrometer.

Results

The correlations between Pb levels and microhardness were very low, and were not statistically significant at p < 0.05.

Conclusions

Previous exposure to high levels of Pb was not associated with decreased tooth microhardness.

Clinical significance

This study assessed whether Pb in deciduous teeth is associated with tooth microhardness. As this was not the case, further studies are needed to identify the mechanisms behind the association between lead exposure and tooth decay.

Lead associated caries development in children living in a lead contaminated area, Thailand

In an observational cross-sectional design, a sample of 292 children aged 6-11 years from two primary schools around a shipyard area, known to be an area contaminated with lead (from the industry), were examined to verify the cariogenicity of lead. The number of decayed and filled surfaces on deciduous teeth (dfs), and the number of decayed, missing, and filled surfaces on permanent teeth (DMFS), the salivary flow rate, pH, buffer capacity, oral hygiene, Lactobacillus spp. and mutans streptococci counts were recorded. The mean (range) of DMFS and dfs were respectively 1.3 (range 0-17) and 13.2 (range 0-45); and the geometric mean blood lead level (PbB) and SD were 7.2 and 1.5 microg/dl. The level of dfs, but not DMFS correlated with the blood lead level (R(s)=0.25, p=0.00 / R(s)=0.09, p=0.14). The odds ratio for DMFS>or=1 and dfs>5 for a doubling of PbB after adjusting for other factors were 1.28 (95%CI, 0.81-2.04; p value=0.35) and 2.39 (95%CI, 1.36-4.20; p value=0.004), respectively. The cariogenicity of lead is evident in deciduous teeth but not in permanent teeth for this age group.