A mouthful of trouble

Mercury fillings are now linked to a range of symptoms, from chronic anxiety to Alzheimer's. Should we have them removed?

Mary Stephenson symptoms began to develop soon after the birth of her first child left her with a calcium deficiency that meant she needed amalgam fillings in 19 teeth. Now, after 40 years of continued illness, unrelieved by a variety of antidepressant treatments, she has finally recovered, she claims, by having all her amalgam fillings removed, along with a course of detoxification to remove the mercury that was left in her body.

Mary Stephenson symptoms began to develop soon after the birth of her first child left her with a calcium deficiency that meant she needed amalgam fillings in 19 teeth. Now, after 40 years of continued illness, unrelieved by a variety of antidepressant treatments, she has finally recovered, she claims, by having all her amalgam fillings removed, along with a course of detoxification to remove the mercury that was left in her body.

It took three months for Mrs Stephenson to start to get better. She noticed the change on a theatre visit in October this year. "In the interval, I went to the toilet and as I was walking up and down the stairs I thought, 'I'm a free person.' That was lovely."

Mercury poisoning from amalgam fillings has been linked to a range of neurological problems, including chronic fatigue, Alzheimer's and multiple sclerosis - as well as symptoms such as nervousness, irritability, lack of concentration, loss of memory and confidence, mood swings, anxiety and insomnia. And mercury-free dental surgeries are thriving.

Amalgam fillings normally contain 50 per cent mercury as well as a varying mix of silver, tin, copper and zinc. No reliable multi-centre research data exist to support fears that mercury in fillings has a toxic effect on the brain or central nervous system, but small studies have suggested that dentists and dental assistants who experience mercury exposure through handling amalgam do have a higher than average risk of neurological disturbance.

Experiences such as Mrs Stephenson's illustrate what seems a highly plausible theory: that it's madness to place a highly toxic substance, even in tiny amounts, so close to the brain and the central nervous system. The Department of Health already advises against amalgam fillings for pregnant women, and four months ago it announced the phasing out of a mercury-based preservative for baby vaccines.

Details of the new dentists' contract to be introduced in October next year are currently the subject of debate between Government and dentists, but it is widely known that non-amalgam fillings will be available on the NHS for the first time - leading, most experts believe, to the phasing out of amalgam.

Conspiracy theories apart, the overwhelming evidence suggests that amalgam fillings are entirely non-toxic. "People are, very rarely, allergic to amalgam. But 100 years of worldwide research has resulted in not a single reputable controlled study showing a connection between amalgam fillings and any medical disorder," says Dr Nigel Carter, the chief executive of the British Dental Health Foundation.

What's more, says the molecular biologist and heavy metals expert Dr Richard Lathe, of Pieta Research in Edinburgh, it's impossible for mercury that has built up over years to be removed from the body in months. "It would take several years of on-off chelation [metal poisoning] therapy, whereas it is known that depression responds very well to suggestion."

Yet the nation would still be healthier without amalgam fillings, believes Dr Harris Sidelsky, a dentist and lecturer at the London Hospital dental school. What makes amalgam fillings dangerous is the preparation, which routinely involves cutting away the healthy tooth around the decay (unnecessary in new, glue-able fillings). The method is linked to the risk of ever-larger fillings, leading to crowns, root-canal work and abscesses.

Dr Sidelsky is a pioneer of minimum intervention (MI) dentistry, which promotes the use of tooth-coloured composites - white plastic fillings that fit into micro-cavities. These are already being superseded by new bio-active materials that simulate body tissue and adhere chemically to the tooth enamel and dentin. Even cleverer filling materials in the pipeline prevent decay by feeding essential minerals, including calcium, phosphate, strontium and fluoride, into the tooth enamel. At the same time, a dental version of keyhole surgery that involves "scooping out" the caries through an access cavity in the side of the tooth further reduces the need to make holes in teeth.

If these developments become available to NHS patients, few will care whether the Government has ditched amalgam over a mercury scare or simply to offer more aesthetic alternatives. However, MI experts warn that technical breakthroughs alone won't bring about real improvement in dental health unless dentists also take on board the key message of MI dentistry, which is to treat the disease that causes decay. "A staggering 90 per cent of current practices focus on invasive techniques to repair damage from disease, without treating the disease itself," Dr Sidelsky says. "In medicine, invasive surgery is the last option. It should be no different in dentistry."

Recent research has established a recognised list of risk factors for dental caries, including genetic susceptibility, the presence of plaque bacteria, and a high sugar diet. "We know that these risk factors vary between individuals, in the same way as people have different risk factors for heart disease. Caries management involves identifying and then eliminating or minimising the individual's risk factors. Research has shown that it is possible to prevent caries occurring as long as the patient is happy to be actively involved in therapy and to undergo regular tests and simple preventive procedures," Dr Sidelski says.

Such patient involvement isn't easy. Luisa Granata, a 31-year-old London lawyer, spent £2,000 on fillings in just two years. "Every time I went to the dentist, another huge cavity would have appeared out of nowhere," she says. "It was terrifying." Then her MI dentist asked whether she would be interested in taking part in a tooth-decay programme, beginning with a "cariogram", a piece of recently developed computer software that analyses risk factors. This showed that Luisa had only a 15 per cent chance of escaping more cavities in the next year.

"The big thing for me was the level of bacteria in my mouth, which the dental hygienist showed me graphically on a TV screen. It was horrifying," Luisa says. A four-day diet sheet revealed part of the cause: "I realised how bad sugary foods are, especially eaten on their own."

A battery of more sophisticated oral hygiene products, including anti-bacterial mouthwash, plaque disclosure products to improve cleaning techniques and saliva-promoting medication, are a big part of MI dentistry. "Problems with saliva production is a major, largely unrecognised, cause of tooth decay. It can be caused by stress or not drinking enough water. It is also a side effect of some drugs and can be a symptom of autoimmune disease, salivary gland malfunction or simply growing older. People often start to get tooth decay in old age because their salivary flow slows down, and is also affected by the drugs they are taking."

Yet these problems can be addressed. Early next year, the journal Quintessence is due to publish Dr Sidelski's blueprint for a UK system of MI dentistry, with dentists paid to provide a modern, and therefore increasingly non-surgical, approach to the management of caries. A highly rated product is Tooth Mousse (produced by the MI dental manufacturers, GC Dental, available from dentists). It is derived from milk and contains an ingredient called Recaldent (also available as a chewing gum) that makes the tooth enamel resistant to acid attack and even hardens up areas that show early decay.

So should people with amalgam fillings go ahead and have them removed? "Definitely not," says Dr Carter. "The invasion has unfortunately already occurred, and unless someone is certain that they are allergic to amalgam, the process of removal can seriously weaken the teeth."

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