Most common teeth X-rays given to millions of Britons every year 'raise the risk of brain tumours'
06:01 GMT, 10 April 2012
Dental X-rays given to millions of Britons each year may raise the odds of developing a brain tumour.
A large-scale study found that men and women with a type of tumour that can affect personality, sight, speech and even paralyse one side of the body, were twice as likely to have had the most common form of dental X-ray than those who were free of the disease.
With another type of tooth X-ray, children appeared to be most vulnerable, with those regularly exposed to the low-dose radiation while under the age of ten, at almost five times greater risk.
Research found having a 'bitewing' X-ray at least once a year raised the odds of developing a brain tumour by between 40 and 90 per cent depending on age. Picture posed by model
Dental X-rays, which are given around 12 million times a year in Britain, have previously been linked to thyroid cancer.
The Yale University brain surgeon behind the latest study advised patients to ask their dentist if an X-ray is really necessary.
But cancer experts have urged people not to worry, pointing out that the brain tumour studied, meningioma, is usually non-cancerous and is very rare.
This means that the odds of developing the disease are ‘tiny’ – even after frequent dental X-rays.
The research team asked 1,400 meningioma patients and a similar number of healthy men and women about how often they had had various types of dental X-ray.
They were also asked roughly how old they were when the x-rays were done.
Collating the results showed that those with the brain tumour were twice as likely to have ever had a ‘bitewing’ X-ray.
A brain surgeon at Yale University (pictured) who carried out the research urged patients to ask their dentist if an X-ray is really necessary
This is the most common type and is taken while the patient bites on an X-ray film coated in lead and plastic placed at one side of the mouth.
Having one of these X-rays at least once a year raised the odds of the disease by between 40 and 90 per cent, depending on age, the journal Cancer reports.
A second type of X-ray, known as panorex, appeared to raise the odds of the disease almost five-fold, when used before the age of ten.
This type of X-ray shows all the teeth and is taken by a camera that rotates around the patient’s head.
Meningiomas make up about a fifth of all brain tumours, with around 900 cases diagnosed a year in the UK.
They grow slowly and it is rare for them to be cancerous. But, depending on their position in the brain, can still cause serious problems by interfering with speech, vision, personality and movement.
Researcher Elizabeth Claus said that much of her data related to x-rays done decades earlier and doses of radiation are lower now than in the past.
Despite this, she advises patients told they are to have an x-ray to question whether it is really necessary.
She said: ‘If there is no benefit oral health, then why not reduce the exposure as much as you can.’
The British Dental Association said that dental x-rays are used more in the US than in the UK and it wouldn’t be normal for someone with healthy diet and healthy mouth to have regular X-rays.
The association said that a return flight to Spain would expose someone to as much radiation as two ‘bitewing’ X-rays.
Scientific advisor, Professor Damien Walmsley, said: ‘X-rays are a vital tool in dentistry and reveal problems in the teeth and surrounding bone that simply cannot be observed by the naked eye, and often before patients experience any pain or discomfort.
‘The earlier dental problems are identified, the easier they are to treat.
‘Regulations governing the use of X-rays in the UK are considerably more stringent than in the US.
‘Dentists in the UK are only permitted to take x-rays where these are absolutely necessary. This means that fewer x-rays are taken in dental practice and modern equipment has reduced exposure to radiation to extremely low levels.’
Paul Pharoah, a Cambridge University cancer expert, described the analysis as sound but said the impact on individual patients would be tiny.
Normally, 15 in every 10,000 people can expect to develop the tumour over their lives. Factoring in the effect of X-rays would increase the figure to 22 per 10,000.
Dr Pharoah said: ‘People who have dental X-rays do not need to worry about the health risks.
‘Nevertheless, dental x-rays should only be used when there is a clear clinical need in order to prevent unnecessary exposure to radiation.’
Others pointed to flaws in the study, saying that relying on people to remember details of their dental treatment, rather than checking their records could have skewed the results.