Since childhood we are told to brush our teeth twice a day, or risk painful cavities and rotting teeth.

But new research suggests that properly cleaning our teeth may also help ward off a particularly vicious form of cancer.

Scientists have discovered that pancreatic cancer - one of the most deadly - is linked to two types of bacteria that also cause gum disease.

A team in the US found that people who had these two bugs in their mouths were up to twice as likely to develop pancreatic cancer over the next decade.

Scientists from New York University found that people who had these two bugs in their mouths were up to twice as likely to develop pancreatic cancer over the next decade

The scientists, who presented their results at the American Association for Cancer Research meeting in New Orleans, said the findings offered an ‘accessible’ means to prevent the disease.

But aside from helping people reduce their risk, they also said it might give doctors a cheap and easy way to screen for the disease.

Pancreatic cancer is the eleventh most common cancer in Britain, with around 9,000 people diagnosed each year.

But it is also one of the most deadly - with only three per cent of patients surviving for five years, compared to 87 per cent for breast cancer and 98 per cent for testicular cancer.

Part of the problem is that the disease causes few symptoms in the early stages, so often goes undetected until the cancer is too advanced to treat.

Doctors call the disease ‘a wolf in sheep’s clothing’ because the symptoms - back ache, jaundice and weight loss - are often mistaken for those of indigestion, acid reflux or back strain.

Effective screening tests are desperately needed - and the presence of bacteria in the mouth could offer such a test.

The scientists, from New York University, tracked 732 people for more than a decade, half of whom went on to develop pancreatic cancer and half who remained healthy.

The researchers, who had taken oral samples at the beginning of the project, found that two forms of bacteria were directly linked to pancreatic cancer risk.

People with the P. gingivalis bug had a 59 percent greater risk of developing pancreatic cancer than those who did not, and those with the A. actinomycetemcomitans bug had an increased risk of 119 per cent.

Both bugs are known to be a cause of periodontitis, a severe form of gum disease.

The team cautioned that they could not be sure that the bacteria actually caused the cancer, because they had only studied the statistical link, and did not know why the bugs might play a role in cancer risk.

British experts said that it may be that people who had a worse lifestyle in general, and so already at greater risk of pancreatic cancer, might be less likely to look after their teeth.

But previous research has suggested that the bacteria in dental plaque build-ups may trigger inflammation, which could lead to cancer.

Pancreatic cancer has the worst survival rate of all 22 common cancers - at just 3 per cent

Aside from helping people reduce their risk, regular teeth-brushing might also give doctors a cheap and easy way to screen for the disease

Researcher Dr Jiyoung Ahn said: ‘Our study offers the first direct evidence that specific changes in the microbial mix in the mouth - the oral microbiome - represent a likely risk factor for pancreatic cancer along with older age, male gender, smoking, race and a family history of the disease.

‘These bacterial changes in the mouth could potentially show us who is most at risk of developing pancreatic cancer.’

Dr Nigel Carter, CEO of the UK Oral Health Foundation, added: ‘Further investigation into this association needs to be carried out but if confirmed there’s no reason why a saliva test to detect for pancreatic cancer could not be taken by your dentist.

‘This would be an enormously important shift in diagnosis which could ultimately save thousands of lives a year.’

He added: ‘Poor oral health has been linked with a multitude of problems effecting our general health. Heart disease, strokes, diabetes and premature births are just some of the things which have all been heavily linked with an unhealthy mouth.

‘What we must remember is oral health is relatively simple to maintain.

'Keeping to a good routine that involves brushing your teeth for two minutes twice a day using a fluoride toothpaste and cutting down on how often you have sugary foods and drinks, are just two of the relatively easy things you can do.’

Fiona Osgun, health information officer at Cancer Research UK, said: ‘It’s vital that we improve survival rates for pancreatic cancer. This new study investigates an interesting avenue of research, but doesn’t confirm a link between oral bacteria and pancreatic cancer risk.

'For now being a non-smoker and keeping a healthy weight are more certain ways to reduce the risk of pancreatic cancer.’