Should you be telling your dentist to hold off on X-rays?
A new study found that people diagnosed with a meningioma, the most common type of brain tumour, had more frequent dental X-rays than those who did not have such a tumour.
But the lead researcher noted the overall risk is relatively small and X-rays have an important role in maintaining dental health.
"We don't want people to panic. And we don't want people to stop going to the dentist," said Elizabeth Claus, a professor at the Yale School of Public Health in New Haven, Conn.
She said the findings should serve as an impetus for patients and dentists to discuss the pros and cons of X-rays – and, when appropriate, to consider whether the number of X-rays might be reduced to minimize radiation exposure.
The study is based on 1,433 individuals who were diagnosed with a meningioma between 2006 and 2011. They were asked a series of questions about their health and medical history, including how often they had dental X-rays. Their answers were compared to a control group of tumour-free volunteers.
The results, published in the journal Cancer, revealed that the tumour patients tended to have more dental X-rays than the controls. Taking X-rays once a year or more frequently appears to increase the risk.
Meningiomas are usually benign, which means they don't spread to other parts of the body. But despite their non-malignant nature, a growing mass can still do serious harm as it presses against the brain. "People can have seizures, lose eyesight, lose speech or lose control of their arms and legs," Dr. Claus explained. "And it can be life threatening." Some tumours cannot be surgically removed because of their precarious location.
Dr. Claus noted that the study participants had an average age of 57, which means they received the bulk of their dental exams in previous decades, when X-ray equipment exposed patients to higher levels of radiation than current machines.
"Today's exposures are much lower and are likely associated with less risk," she said.
Furthermore, many of the study participants reported receiving far more dental X-rays than recommended by the American Dental Association. For healthy individuals, the ADA says children can receive X-rays every one to two years; teens can have X-rays every 1.5 to three years; and adults can get them every two to three years.
"Have a conversation with your dentist about the guidelines and consider whether you might be able to reduce or modify the rate at which you receive dental X-rays," advised Dr. Claus.
Benoit Soucy of the Canadian Dental Association agrees that dental X-rays should be used sparingly.
"There is a small risk attached to the use of X-rays. That risk is related to the total dose received over a lifetime. Therefore you do not want to take unnecessary X-rays," said Dr. Soucy, the CDA's director of clinical and scientific affairs.
"And you only take X-rays that are of diagnostic value, when the information can not be derived somewhere else, and using the lowest possible [radiation] exposure for that patient."