Bisphenol A also lurks in teeth

Just when they thought they could breathe easy after years of controversy concerning mercury-based fillings, dentists are finding themselves at the centre of a new debate over the safety of the alternatives.

An increasing number of dentists are using sealants and fillings that may expose patients to bisphenol A, a chemical the federal government said last week is potentially dangerous and will be banned from use in plastic baby bottles. BPA is a hormone disruptor that can mimic estrogen, and some research has linked it to health consequences, including early puberty in girls, breast and prostate cancer, and attention deficit and hyperactivity disorder.

Some studies have found detectable levels of BPA in the saliva of patients after they received sealants or fillings, but experts are divided as to whether this low exposure constitutes a health risk.

Dental associations are rushing to defend the use of the materials, saying patients' exposure to BPA appears to be low and limited to the period immediately after treatment.