Wednesday, April 11, 2012

New Epidemiology Study Links Dental X-Rays and Brain Tumors

A new study claims that frequent dental X-rays, particularly in childhood, may increase the risk of developing meningioma, the most commonly diagnosed brain tumor in the U.S.

A new study on dental radiographs or x-rays has created quite a flap.

People who received frequent dental x-rays have an increased risk of developing meningioma, the most commonly diagnosed primary brain tumor in the U.S., according to a study published today in Cancer (April 10, 2012).

The findings should serve as a reminder to patients and practitioners alike to carefully assess the need for diagnostic imaging procedures and to limit the frequency of x-rays based on the recommendations of professional organizations, such as the ADA.

Ionizing radiation is the primary environmental risk factor for developing meningioma, a largely benign brain tumor, and dental x-rays are the most common artificial source of exposure to ionizing radiation for individuals in the U.S., the study authors noted.

To examine the link between dental x-rays and the risk of developing meningioma, Elizabeth Claus, MD, PhD, of the Yale University School of Medicine and Brigham and Women's Hospital, together with colleagues from multiple other academic medical centers, studied information from 1,433 patients who were diagnosed with the disease between the ages of ages 20 and 79 and were residents of the states of Connecticut, Massachusetts, North Carolina, the San Francisco Bay Area, and eight counties in Houston, TX, between May 1, 2006 and April 28, 2011.

They also studied information from a control group of 1,350 individuals who had similar characteristics but who had not been diagnosed with a meningioma.

To avoid attributing the effect of therapeutic ionizing radiation to dental x-rays, individuals who had received therapeutic radiation to the head, neck, chest, or face were removed from all analyses that assessed the risk associated with dental x-rays, the study authors noted.

"All epidemiology studies are imperfect and only suggest a correlation, not a cause and effect," Dr. Claus told "But we did collect information on other sources of common ionizing radiation, particularly therapeutic. We tried to control for other things that we knew would be an issue."

Here is the video report:

And, what is a bitewing x-ray?

Here is a video for my non-dentist readers:

So, what does this all mean?

Dentists should be judicious in their use of all ionizing radiation whether it be simple diagnostic bitewing x-rays or more elaborate Cone Beam CT-3D imaging. And, again, imaging should be based on sound professional judgment - not as a routine.

There have been many criticisms of this study in just the past day, including from the American Dental Association, but the study should serve as a reminder to dentists and patients alike.

The ADA has reviewed the study and notes that the results rely on the individuals' memories of having dental x-rays taken years earlier. Studies have shown that the ability to recall information is often imperfect. Therefore, the results of studies that use this design can be unreliable because they are affected by what scientists call "recall bias." Also, the study acknowledges that some of the subjects received dental x-rays decades ago when radiation exposure was greater. Radiation rates were higher in the past due to the use of old x-ray technology and slower speed film. The ADA encourages further research in the interest of patient safety.

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