Dental X-rays may up tumour risk

People who have received more than one dental X-ray a year are twice as likely to develop a common type of brain tumour, claims a new study, suggesting that the procedure should be undertaken as less as possible.

A team led by researchers from the Yale University School of Medicine in the US found that people who reported having more than one dental X-ray a year were 1.4 times to 1.9 times more likely than those who did not to have diagnosed with meningioma, a common but potentially debilitating type of non-cancerous brain tumour.

Individuals who reported receiving these exams when they were younger than 10 years old had a 4.9 times increased risk of developing meningioma, the researchers found. “The study highlights the need for increasing awareness regarding the optimal use of dental X-rays, which unlike many risk factors, is modifiable,” said lead author Elizabeth Claus, a professor at Yale and a neurosurgeon at Brigham and Women’s Hospital in Boston.

However, she said people should not overreact to their findings.

 “Our take home message is don’t panic. Don’t stop going to the dentist,” she was quoted as saying by msnbc.com.

According to the researchers, dental X-rays are the most common synthetic source of exposure to ionising radiation for individuals — the primary environmental risk factor for developing meningioma.

These tumours grow in the lining inside the skull. Most are slow growing but they can cause problems if they start to press on the brain, and they can be lethal.

In their study, published in the journal Cancer, the team looked at two types of head X-ray called bitewing and Panorex as they analysed data from 1,433 people who were diagnosed with the disease. They also included data from a control group of 1,350 people with similar characteristics who did not have the tumour. The mean age was over 57 years for both groups.

The study found that over a lifetime, individuals who developed meningioma were more than twice as likely as those in the control group to report having received bitewing exams — which use X-ray film held in place by a tab between the teeth — on a yearly or more frequent basis.

The researchers also found a link between meningioma risk and the panorex dental exam (which uses an X-ray outside of the mouth to develop a single image of all of the teeth).

The authors said that significant increases in risk were associated with young age at the time of screening, as well as more frequent screening. Individuals younger than 10 years old who received this exam in the past had a nearly five times greater risk of developing meningioma, they found.

Among people of all ages, those who received the panorex exam on a yearly or more frequent basis were up to three times more likely to develop a tumor, they said.Cancer experts, however, urged people not to worry saying the tumour studied is very rare and usually non-cancerous.

“The strongest thing you can say about this study is that there is a suggestion of a link between dental X-rays and meningioma,” Dr Otis Brawley, scientific director at the American Cancer Society, was quoted as saying.