The research also suggests – based on a small number of tumour patients – that excessive use of mouthwash may also cause this particular form of cancer.

Excessive use is defined as more than three times a day. It has been established for some time that smoking and heavy alcohol consumption, particularly in combination, are strongly related to mouth and throat cancers.

Low socio-economic status is also recognised as a contributory factor.

Low, however, a new study carried out by researchers at the University of Glasgow Dental School has identified new risk factors for upper aerodigestive tract cancer (cancer of the mouth, larynx, pharynx and oesophagus).

The study of 1,962 patients with mouth and throat cancers, with a further 1,993 people used as comparison control subjects, was conducted in 13 centers across nine countries and supported by EU funding.

Prof Wolfgang Ahrens, Deputy Director of the BIPS, said, "These results are really important. Up until now, it was not really known if these dental risk factors were independent of the well known risks for mouth and throat cancers – smoking, alcohol and low socio-economic status".

The researchers were able to strip out the causation factors of smoking, alcohol and socio-economic factors, and still found there was a connection between poor oral health and increased risk of mouth and throat cancers.

The findings are highly "nuanced" and there is an interconnectedness of many of the risk factors, he stressed, but there was no evidence that poor oral health and poor dental care were also part of the picture.

The definition of poor oral health included people who had complete or part dentures, and people with persistently bleeding gums.

"People should not assume that if they wear dentures and have none of their own teeth left, they have no need to see a dentist," said Dr David Conway, Clinical Senior Lecturer at the University of Glasgow Dental School and one of the senior
authors of the study.

"On the contrary, even if you have got dentures, you should make sure you go for regular check-ups," he said.

People with poor dental care were defined as those who hardly ever or never brushed their teeth or visited the dentist.

The frequency of dental visits should be determined by a dentist's risk assessment and if people fell into the low risk category it could be once a year or even every two years, said Dr Conway.


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