People who get regular dental X-rays are more likely to suffer a common type of brain tumour, US researchers said, suggesting that yearly exams may not be best for most patients.
Over a lifetime, having dental X-rays can double or triple the chances of developing meningioma tumours
The study in the US journal Cancer showed people diagnosed with meningioma who reported having a yearly bitewing exam were 1.4 times to 1.9 times as likely as a healthy control group to have developed such tumours.
A bitewing exam involves an X-ray film being held in place by a tab between the teeth.
Also, people who reported getting a yearly panorex exam – in which an X-ray is taken outside the mouth and shows all the teeth on one film – were 2.7 to three times more likely to develop cancer, said the study.
A meningioma is a tumour that forms in the membrane around the brain or spinal cord. Most of the time these tumours are benign and slow growing, but they can lead to disability or life-threatening conditions.
The research, led by Elizabeth Claus of the Yale University School of Medicine, was based on data from 1,433 US patients who were diagnosed with the tumors between the ages of ages 20-79.
For comparison, researchers consulted data from a control group of 1,350 individuals who had similar characteristics but had not been diagnosed with a meningioma.
Dental patients today are exposed to lower radiation levels than they were in the past, but the research should prompt dentists and patients to re-examine when and why dental X-rays are given, said Dr Claus.
“The study presents an ideal opportunity in public health to increase awareness regarding the optimal use of dental X-rays, which unlike many risk factors is modifiable,” she said.
The American Dental Association’s guidelines call for children to get one X-ray every one to two years; teens to have one every 1.5 to three years, and adults every two to three years.
Michael Schulder, vice chairman of the department of neurosurgery at Cushing Neuroscience Institute said he was not shocked by the findings.
“This should come as no great surprise given the connection between radiation and meningioma development that has been established in various other contexts,” said Dr Schulder.