New study on dental x-ray-brain tumor risk not reliable

A recent study in the scientific journal Cancer associated an increase risk of the brain tumor Meningioma with an increased frequency of dental x-rays. Meningioma is the most common brain tumor and is usually benign. Even so, this alarming study made national news and will likely cause many people to be needlessly fearful of receiving dental x-rays. 

Even though it is well known that dental x-rays have extremely low radiation, I took the time to read the entire study published in Cancer.  What I read shocked me.  It wasn’t that there could be a risk of Meningioma from dental x-rays, but that the study was based on how may x-rays each person remembered they had over the last 50 years!  Can you remember how many dental x-rays you received over even the last 5 years? I doubt you can.  I doubt I can, and I’m a dentist.  I asked several of my patients, including a physician, and not one of my patients could accurately remember the amount of x-rays they had at my office over the last five years.  One thing that was consistent was that every patient I asked overestimated the actual amount of x-rays they had received. 

The most obvious thing to want to know is why didn’t they just go to each person in the study’s dentist and find out the actual amount of x-rays they had received.  Here is what the authors wrote about that “…dental care generally is obtained (even for a single individual) from numerous dentists, all of which are outside of a health maintenance organization or hospital-based setting, providing little opportunity for researchers to validate dental reports in a timely or cost-efficient manner.”  This is beyond ridiculous.  Basically it would take too much time or cost too much money to actually do a study with reliable and verifiable information. Perhaps the real results would not validate the conclusion that dental x-rays increase Meningioma risk. 

Dental x-rays (or radiographs) are an important part of a thorough dental examination. A full set of x-rays (18) or one large x-ray called a panoramic x-ray is usually required for patients who are new to a dental practice, or who need extensive treatment. Two to four follow-up or check-up x-rays called 'bite-wings' are necessary every 6-24 months, depending on each individual patient's needs.

Dental x-rays are important for many reasons. They can expose hidden dental decay, reveal a dental abscess, cyst, or tumor, show impacted or extra teeth,
and also help determine the condition of fillings, crowns, bridges, and root
canals. Dental x-rays can also reveal bone loss from periodontal (gum) disease,
locate tarter build-up, find foreign bodies within the gum or bone, and see if
there is enough bone for the placement of dental implants. These are just some
of the many reasons why dentists rely on dental x-rays. Dental x-rays expose a
patient to a very low level of radiation. A full series of dental x-rays (18)
has 27 times less radiation than a lower gastrointestinal (GI) series and 20
times less radiation than one year of normal background radiation from the
environment. Dental check up x-rays (4 bitewings) has 79 times less radiation
than a year of normal background radiation.

In spite of these low radiation levels, dentists are very concerned about minimizing the amount of radiation a patient receives at the dental office. That's why we use special high-speed film, can use digital x-rays, and cover patients with a lead apron during x-ray procedures. Dental x-rays are very safe and extremely important to you and your dentist and should not be avoided based on unfounded fears about radiation exposure.

This study by lead author Elizabeth B. Claus MD, PhD in Cancer is one of the most irresponsible things I have every read coming from the medical community. It is also very interesting to note that not one dentist was involved with publishing this study. So the question remains:  Is it possible that dental x-rays can cause brain tumors? Sure it’s possible, but very unlikely and will be not known until a reliable study is conducted.

Source: http://onlinelibrary.wiley.com/doi/10.1002/cncr.26625/full