People with eight or more fillings are at the greatest risk of major organ damage; they have 150 per cent more mercury in their blood than someone who doesn’t have any fillings. In the US, 25 per cent of the population has 11 or more fillings.
But the risk exists for everyone with mercury fillings, say researchers from the University of Georgia. Our gut transforms the mercury into methyl mercury, the most lethal form of the heavy metal, and other research has shown it can cause damage to the organs even at low levels.
Dental amalgam—which is 50 per cent mercury—has been used as the standard filling material for 150 years, and the dental associations have always maintained it is safe, and doesn’t enter the blood stream.
But when the researchers analysed blood samples from 14,703 adults in the US, they discovered a connection between the levels of mercury in their blood and the number of amalgam fillings they had. “As toxicologists, we know that mercury is poison, but it all depends on the dose. So, if you have one dental filling, maybe it’s OK. But if you have more than eight dental fillings, the potential risk for adverse effect is higher,” said Xiaozhong Yu, one of the researchers and an assistant professor of environmental health science.
Our mercury levels can also be increased by eating contaminated fish and from our environment.
Amalgam alternatives, such as dental composite resins, are safer and don’t ‘leak’ into the bloodstream, they say.