- Warning from Dr David Conway of University of Glasgow Dental School
- Major study examined the health of 4,000 people across nine countries
- British Dental Association argued results of study were not conclusive
Poor oral health – one of the reasons people regularly use the rinses – also plays a part in cancer risk, he added.
The research supports an Australian study in 2009, which said there was ‘sufficient evidence’ that mouthwashes containing alcohol contribute to an increased risk of the disease, because they allow cancer-causing substances to penetrate the lining of the mouth more easily.
In the latest study, in journal Oral Oncology, University of Glasgow researchers and European colleagues assessed 1,962 cancer sufferers and 1,993 healthy people in 13 centres across nine countries.
Those with poor oral health, including people with dentures and persistently bleeding gums, were at greater risk, they found.
The study set out to identify risk factors for oral cancers affecting the mouth and larynx, as well as oesophageal cancer of the gullet.
Dr Conway said ‘I would not advise routine use of mouthwash, full stop.
‘There are occasions and conditions for which a dentist could prescribe a mouthwash – it could be that a patient has a low salivary flow because of a particular condition or medicine they are taking.
‘But for me, all that’s necessary in general is good regular brushing with a fluoride toothpaste and flossing combined with regular check-ups by a dentist.’
He added there may be a link between excessive mouthwash rinsing and people who use it to mask the smell of smoking and alcohol – independent risk factors for oral cancer.
The researchers were unable to analyse the types of mouthwash because they were used many years ago by those in the study.
Professor Damien Walmsley, adviser to the British Dental Association, said the study was not ‘conclusive’.
‘It does, however, reaffirm that smoking together with heavy drinking and a poor diet over time are strong risk factors for developing cancers of the oral cavity and oesophagus,’ he said.
‘Unfortunately, these behaviours cannot be disassociated from people who neglect their oral hygiene and rarely, if ever, visit the dentist, as this study suggests.
‘It also highlights that people, who are at risk of developing these cancers, may be using alcohol-based mouthwashes inappropriately to disguise smoking or drinking alcohol.
‘Mouthwashes should be used according to manufacturer’s directions.’