Dental X-rays have been linked to meningioma, the most common type of brain tumor, according to a new study by the American Cancer Society, reports theWashington Post. The biggest correlation was found with bitewing X-rays, when a patient bites on the film while an image is taken; according to the study, people with meningioma were more than twice as likely to have had at least one bitewing X-ray.

Researchers cautioned that the study examined people who had received X-rays in the 1960s, when the procedure used much more radiation than today. Another dental X-ray technique that increased the chances of meningiomas was the panorex exam, which takes a complete panoramic image of all the teeth. People who had a panorex X-ray before 10 years old were 4.9 times more likely to develop meningioma. Meningioma tumors rarely become malignant, but can cause problems as they grow because they can interfere with brain function.

Read more: Newser