To X-ray or Not X-ray?

A recent study published in the scientific journal Cancer associates dental X-rays with an increased risk of developing meningioma, the most commonly diagnosed brain tumor in the U.S. The study caught the attention of many major news outlets and seemed to have create a small panic in the general public that were getting routine X-rays at their dental offices.

The study included 1433 meningioma patients and a control group of 1350 control group individuals. The cancer patients reported having regular bitewing, full mouth, and or panorex dental x-rays. The results showed that patients with meningioma were twice as likely than the control patients to have had bitewing x-rays.

When the general public hears this type of information, they are not always given the full picture to keep things in perspective. In addition, they are not always told how the study was conducted and more importantly, do not always have the science and research background to critically analyze the studies that are cited.

In response to this study, the American Dental Association, Division of Sciences, carefully reviewed the study and noted some major weaknesses in the study design and interpretation of the results:

1. The findings are based on patient recall of x-rays taken decades ago, not the actual doctor's charts.  People's memories can be unreliable. 

            2. The results of the study did not appear to be dose-related. As one would expect, the higher the dose, the higher the chance of getting cancer.

            3. The study was observational, meaning it cannot establish a cause-and-effect relationship between dental x-rays and meningioma.

            4. Advances in x-ray technology over the last several years has greatly reduced the amount of radition exposure per x-ray taken.

Considering the weaknesses of the study, and the small size of the reported effect, this study should not raise significant concerns. The study does not suggest that dental x-rays cause brain tumors. However, it does remind us that dental x-rays should only be taken when the patient's dental health and treatment will be affected. We should always return to the old acronym we learned in dental school: A.L.A.R.A. In other words, clinicians should always follow the ADA guidelines to help ensure radition is kept At Levels As Low As Reasonably Achievable.