You'd think that the state of your gums would bear little relation to the rest of your body, but studies show that those of us who suffer from gum disease (periodontal disease) have a higher likelihood of heart attack and stroke. There has even been a recent suggestion of a link between gum disease and cancer. The only problem is that nobody has been able to establish for sure whether one disease causes the other.

This week, however, New Zealand scientists claimed a breakthrough. They say the body's defences overreact to the threat of gum disease and start to destroy other protective cells too. This, they claim, leads to atherosclerosis, a furring of the arteries - the primary cause of heart attack.

Sadly, this new study has not yet been published. But if gum disease really does cause heart attacks, then the public health implications of a toothbrush and a tube of Macleans start to look distinctly huge. One British adult dies from heart disease every three minutes. Approximately 10-15% of us have advanced periodontitis and around 50% of us have bleeding gums (gingivitis: an early sign of periodontitis).

But there is no need to panic-buy dental floss just yet. Professor Peter Weissberg, medical director of the British Heart Foundation, is sceptical, pointing to evidence from previous studies showing no causal link. When patients with heart disease and periodontal disease were given antibiotics for the latter, they still had heart attacks.

There is, meanwhile, tonnes of evidence that people with bad teeth are more likely to smoke, or neglect other parts of their body. The British Dental Association is similarly dubious about causality, but points out that gum disease is nasty enough - and preventable if you brush and floss. Since this only takes two minutes, it must surely be worth hedging your causal bets.