DENTAL X-RAYS

Study Links Dental X-rays to Risk of Brain Tumors

A new study published in the American Cancer Society peer-reviewed journal Cancer finds people diagnosed with the most commonly diagnosed primary brain tumor in the United States reported twice as frequent dental x-rays in the past. Led by Elizabeth Claus, MD, PhD, of the Yale University School of Medicine in New Haven and Brigham and Women's Hospital in Boston, researchers studied information from 1,433 patients who were diagnosed with the disease between the ages of ages 20 and 79 years between 2006 and 2011. The investigators compared answers to a health survey to answers given by a control group of 1,350 individuals who had similar characteristics but who had not been diagnosed with a meningioma. They found patients with meningioma were more than twice as likely as controls to report having ever had a bitewing exam, which uses an x-ray film held in place by a tab between the teeth, or panorex exams, which are taken outside of the mouth and show all of the teeth on one film, taken at a young age or on a yearly or more frequent basis. Below are comments from Otis W. Brawley, M.D., chief medical officer for the American Cancer Society, regarding the study. "It's important to recognize that this is what is called a case control study, which by its very nature is limited in the conclusion one can draw from it. You cannot conclude based on this study that people who got more dental x-rays were at higher risk of brain tumors. All that we can reasonably conclude from this study is that it suggests that there may be a link between dental x-rays and brain tumors, and that further research into the issue is justified. What the study actually found was that people with these tumors, when asked in a survey, reported having more x-rays in the decades before. That could mean one of two things: that x-rays may increase the risk, or that people who have been treated for these brain tumors remembered and reported having more dental x-rays than healthy people. That's called recall bias and is a common problem with these studies. "We need more data before we can even begin to state there is a relationship between dental x-rays and these tumors. Until that research is done, the best advice we can give people is to get dental x-rays when they are necessary and only when they are necessary. The dose of radiation given in a bitewing or panoramic x-ray is lower today than it was two decades ago. Nonetheless, x-rays should be done only when necessary. This is true of all x-ray technology, and it's the same advice experts would have given without this study. Even the American Dental Association says that although radiation doses in dental radiography are low, exposure to radiation should be minimized where practicable, and that dentists should weigh the benefits of dental radiographs against the consequences of increasing a patient’s exposure to radiation, the effects of which accumulate from multiple sources over time."