Reprinted from New Scientist, 18/1/97, with kind permission.

Lead pollution from traffic fumes and tap water may cause tooth decay, say Spanish researchers, Francisco Gil and his colleagues at the University of Granada have found that teeth from children and adults that contain high concentrations of lead have more caries, plaque and dental staining

Measuring the lead content of children’s milk teeth as they are shed is a standard test for exposure to environmental lead and its accumulation in the body. Gil’s team also found that children with 10 or more sites of decay in their mouths had three times as much lead in their blood as children with no decay.

The researchers, whose results appear in the December issue of The Science of the Total Environment, suggest that lead either goes directly into the mouth, where it replaces traces of metals that are natural constituents of tooth enamel, or that it reaches teeth via the blood. Once present in the tooth, the researchers believe that lead makes the enamel more susceptible to attack by bacteria. Their discovery may explain why older people, who over the years accumulate more and more lead in their teeth, suffer most from tooth decay.

The study is the first published analysis to find a significant correlation between lead and dental decay. But Lindsay Paterson and Philip Sutcliffe of the University of Edinburgh say that they made a similar finding in the early 1990s. "We also found a statistically significant association," says Paterson. "We had intended to publish the results, but Sutcliffe, the lead author, got involved in a long campaign to save the university’s dental school."