An amalgam of half-truths
October 2nd 2012, 16:11 | Bryan Hubbard
The news that the European Parliament is expected to ban mercury fillings throughout the 27 member states, including the UK, raises two questions: why was mercury ever put in our teeth in the first place, and why have the dental associations always been so ready to defend the use of one of the most toxic elements?
The answer to the first question is now lost in the mists, although cost appears to have been an over-riding factor when it was mooted as an acceptable filler of dental cavities around 160 years ago. Gold was the only material available, and mercury was more pliable, durable - and far less expensive. By mixing it with copper, tin and silver - thus creating an amalgam, the name given to the fillings - dentists believed the mercury would be stabilised and 'locked in'. And as the early patients seemed able to stand and walk out of the surgery, dentists believed it was safe.
But the mercury wasn't locked in. By the 1970s, sophisticated technology such as mass spectrophotometry could 'see' mercury vapours coming out of the fillings, forcing the dental associations to shift their ground. The fillings were releasing such small amounts of mercury that it wasn't doing us any harm, unless we had a 'mercury sensitivity' (doesn't everyone?), and that applies to just 3 per cent of the population, reckons the British Dental Association. It's a conservative estimate, but it still represents an epidemic, according to official public health definitions of what an epidemic looks like.
From the vapours being released from the fillings, the mercury makes its way into all our tissues and organs, and especially to the kidneys. Indeed, the European Commission states that we ingest more mercury from our fillings than from any other source, including fish. The amount varies, of course, depending on the number of amalgam fillings we have, but it can up to five times the levels our bodies can tolerate and dispose of.
Conspiracy theorists believe the dental associations won't come clean about amalgam fillings because of the deluge of legal claims that would follow, but absolute proof that dental fillings have directly caused a chronic health problem is almost impossible to establish.
Rather, we think it's because it would cause a national panic. Most dentists have not been trained in removing amalgam - and the release of mercury during the procedure could be catastrophic.
Instead, it takes the European Parliament to make the decision while dentists - quietly, quietly - move to safer materials, as they started to do 20 years ago.