Dental X-Ray Safety Concerns
JANE SYMONS By JANE SYMONS
Posted June 12, 2010
REGULAR X-rays have long been a feature of routine dental checks and few of us gave them a second thought -- until last week when a new study warned that these scans could double the risk of developing thyroid cancer.
An international study of just over 300 thyroid cancer patients found that repeated X-rays dramatically increased the risk of the disease, prompting researchers to question the widely held belief that dental radiography is absolutely safe.
Experts are divided on how much weight to put on the study -- which relied on patients' recall of X-rays and was carried out in Kuwait, where there is a much higher incidence of the disease than the UK. But they do agree that the thyroid and surrounding tissue is highly sensitive to radiation.
A number of earlier studies have reported a link between dental X- rays and cancers of the thyroid, salivary glands and brain, and it's known that dentists and their assistants are at higher risk of tumours.
And although thyroid cancer is relatively rare (around 1,900 patients are diagnosed annually in the UK), the incidence has more than doubled from 1975 to 2006. Over the past two decades there has been a similar explosion in other oral cancers.
Dick Handscombe, who was diagnosed with cancer of the salivary glands after having dozens of X-rays as a child, has no doubt they are dangerous.
Growing up in Harrow, North London, he would often help out in the family bakery business and was particularly fond of icing cakes using a piping bag made of folded paper.
In those pre-health-and-safety days, it was common practice to pop the tip of the piping bag between your teeth to remove any excess between each section of icing.
AS A RESULT, Dick, 73, a management consultant turned gardener and author, admits: 'Every tooth had a filling.' 'I remember having X-rays all the time,' he says.
'If you went for a filling it was unlikely that you didn't have an X-ray. I must have had 30 in my younger days.'
He adds: 'The dentist and assistant would leave the room, but it never occurred to me there was any risk.'
In 1991, Dick discovered a lump on his neck, but for two years his GP said it was nothing to worry about. It wasn't until 1993, when he was waking every morning with a mouthful of blood and the lump began to throb, that he was referred to a specialist, who confirmed it was cancer of the salivary gland.
One of the first questions his consultant asked Dick was how many X-rays he had as a child.
Exposure, particularly in childhood, is an acknowledged risk factor for thyroid cancer.
In the Ukraine, there was a sharp rise in cases after the Chernobyl nuclear reactor accident, and a similar leap was seen in Japan among survivors of the atomic bombs dropped on Hiroshima and Nagasaki. But the new research suggests that much lower doses also pose a threat.
Dr Anjum Memon, of the Brighton and Sussex Medical School, who led the study, said his findings show that multiple low-dose exposure may be a risk factor.
He has called for a rethink on the use of X-rays as part of routine check-ups and for greater caution when using them on children.
However, Professor Damien Walmsley, scientific adviser to the British Dental Association, says the levels of radiation used in dentistry are extremely low and are being monitored and reduced.
Dr Kelly Classic, a health physicist at the Mayo Clinic, agrees. 'This study doesn't say "Yes, it's definitely a problem", but it is certainly something we need to continue to pursue,' she says.
'We have seen from the Chernobyl data that if someone is under the age of 15 and exposed, it is a significant risk.'
Dr Classic says patients should challenge dentists if they suggest frequent X-rays. 'If I had no symptoms and I've had a full set of Xrays, I'm going to hold off for at least a couple of years.'
Professor Walmsley adds that X-rays are useful at picking up the early signs of decay. It's important to balance the small risk of radiation against the real danger posed by dental problems, he explains.
CANCER survivor Dick believes the risk is too great. After two rounds of surgery to remove a tumour 2cm by 4cm from his salivary gland and surrounding lymph nodes, he was given the all-clear and advised to refuse dental Xrays in future. He said: 'I haven't had a dentist argue.'
On his doctor's advice, in 1994 he moved to Spain, where he met his wife, Clodagh, and they began a new life as gardeners and authors based in a village near Valencia.
He is a keen rambler and attributes a Mediterranean diet, based on organic produce, for his good health. Dick says: 'There is enough proof radiation can affect you, so why is it part of the regular check-up?' He believes it's 'just another money-spinning add-on'.
'You don't need an X-ray to tell you you've got toothache.' However, dentists carry out only essential X-rays, according to Dr Nigel Carter, of the British Dental Health Foundation.
He added that as most patients are treated under the NHS or through fixed-payment schemes, dentists have nothing to gain by adding on unnecessary services.
But Lynne McTaggart, editor of What Doctors Don't Tell You, says: 'There is no such thing as a safe dose. There is a shocking disregard for the danger they pose.'
She advises asking your dentist for a shield to protect other parts of the body from radiation.
In the U.S., it is routine to use a thyroid collar, a plastic guard which is lined with lead and held over the neck during X- rays.
But Professor Walmsley says the current thinking in Europe is that the shields may do more harm than good: 'With a thyroid collar, you run the risk of scattering radiation back into the body.'
He said the collimated X-ray machines used in modern dentistry mean there is minimal risk of radiation scattering.
These machines consist of a lead-lined column on a flexible arm which is placed over the area to be X-rayed and are used in most practices.
As a result of such developments, Lynne McTaggart said levels of radiation used in dentistry have been reduced by a factor of three in the past 15 years. But she warns that the popularity of cosmetic dentistry and orthodontic work meant they were being more widely used.
Her advice: 'If you are offered an X-ray, you should ask: "Do I really, really, need this?" '
TO REDUCE your risk of radiation exposure, take the following steps:
DON'T have regular routine X-rays. If you have no ongoing dental problems, scans every two years, or more, are sufficient. Question your dentist if they suggest them.
IF you change dentists, take a copy of your X-rays to the new surgery.
USE an NHS dentist or arrange treatment under a set-payment scheme such as Denplan -- if there is no fee per service, there is no financial incentive to offer unnecessary extras.
MAKE sure your surgery uses a collimated X-ray machine -- they have a flexible arm which is placed against the face. For even lower exposure, find one which uses a digital X-ray -- look for wires from the mouthpiece.
IF children need orthodontic work which will involve X-rays, consider delaying treatment until they are 15.
KEEP a note of all X-rays to monitor your own exposure.
EVERY dental surgery has a staff member appointed to monitor radiation issues. Speak to them if you have any queries.
© 2010 Daily Mail. via ProQuest Information and Learning Company; All Rights Reserved
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