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 μg/dl. The level of dfs, but not DMFS correlated with the blood lead level (Rs = 0.25, p = 0.00 / Rs = 0.09, p = 0.14). The odds ratio for DMFS ≥ 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.