In 1989, Professor Murray Vimy from the University of Calgary in Canada studied the effects of mercury fillings on sheep.

His research team used radioactively-labelled mercury for ease of tracking and found substantial quantities of the element in all major organs within 30 days of amalgam placement.

Most worrying was that mercury crossed the placenta in pregnant sheep, with high levels showing up in the unborn lambs.

Mercury vapours are continuously released from fillings, especially when we consume hot or acidic food and drink.

Many of my clients have detectable levels of mercury in their hair but not all are equally affected.

Whether someone is pushed over the toxicity threshold depends largely on genetics, lifestyle and environment.

To date, mercury has been linked with a host of immune and digestive disorders as well as liver and kidney damage, dermatitis, neurological and mental deterioration.

In 1998, the British Dental Association (BDA) finally recommended that pregnant women should no longer be given mercury fillings.

So is it okay for the rest of us? The BDA assures us that mercury becomes "lockedin"

when mixed with other metals and we only absorb insignificant amounts.

However, the World Health Organisation states there is no such thing as a safe level of mercury.

Generally, fillings contain 50 per cent mercury. The rest is made up of silver, copper, tin and zinc.

Some old fillings have been found to contain as little as 10 per cent mercury.

This is hardly surprising as mercury in the mouth finds itself in a saliva-rich, abrasive environment which actively encourages its release. The missing 40 per cent would have been swallowed, inhaled or absorbed.

The BDA knows we are dealing with one of the most toxic materials on the planet.

All dental staff are given strict guidelines on how to handle and dispose of mercury safely and warned about its hazards.

Yet, the BDA is unlikely to change their mind about prohibiting its use in our heads. And for good reason.

Just imagine the stampede if millions of people rushed to have all their old fillings removed. Or the hefty claims for compensation if the dental profession admitted to having made a terrible mistake when they introduced mercury amalgams 150 years ago.

We hope for enlightened dentists and viable alternatives.

These are improving all the time and based on plastic, gold or porcelain.

Fitting them is more expensive and requires more time and expertise but they are surely worthy of attention if we value our health.

The British Society for Mercury-Free Dentistry provides a list of dentists trained to remove amalgams safely (tel 0207 373 3655).

Dr Philip Yellowley, for instance, uses rubber dams and specialised suction tips when removing mercury laden teeth to reduce exposure to a minimum. During the procedure, patients are kitted out with goggles and breathe pure oxygen.

Patients are also given specific advice on how to detox before, during and after treatment.

Dr Yellowley practices at the Hove Court Dental Centre, 2 New Church Rd, Hove (tel 01273 770377 or visit