People who have had frequent dental X-rays may have an increased chance of developing a meningioma, one of the most commonly diagnosed brain tumors, according to a new study. Most meningiomas are non-malignant, but they can grow very large. Depending upon their location in the skull, they can also cause severe symptoms like memory loss, frequent headaches, vision and hearing loss and seizures. Ionizing radiation, such as X-rays, is the biggest risk factor for developing a meningioma. For most healthy people in the U.S., dental X-rays are the most common source of this type of radiation. In the study, which was published in the journal Cancer, researchers found that people who reported having “bitewing” dental X-rays at least yearly had a 40 percent to 90 percent increased risk of meningioma. Patients who were diagnosed with meningioma were also more than twice as likely to have had a dental X-ray at some point in their life. Panoramic X-rays, which involve the upper and lower jaws, were also associated with an increased risk. This was almost five times greater for those who had a panoramic X-ray before the age of 10. The study does not show that dental X-rays cause brain tumors, only that there is an association. Researchers point out, though, that many people may be receiving X-rays more frequently than recommended by the American Dental Association—every two to three years for adults, one to two years for children, and 1.5 to three years for teens. You cannot undo your exposure to radiation from dental X-rays, but you can talk to your dentist about limiting them to less than annually, unless it’s medically required.