Dental X-Rays And Cancer: A New Scare

Dental X-Rays And Cancer: A New “Study”


It hasn’t even been a year since I wrote an article about a statement by Dr. Oz saying that dental x-rays were related to an increase in the incidence of thyroid cancer.

Now a new study is being quoted saying that there is a higher incidence of meningioma, a benign brain tumor, in people that had dental x-rays and the media is running with it.

The study was based on answers to questions in a survey of over a thousand patients with meningioma. One of the questions asked was whether the patients remembered having dental x-rays taken. The implication here is that x-rays can cause cancer.

In my opinion, this type of study should not even be published, since it does not prove anything, and it only serves to fuel concerns in the general public that, although legitimate, they are often fuel for those that take an exaggerated or extremist point of view.

Let me explain why I say that the study is useless as a scientific paper.

The method by which the study was conducted was a survey where the author asked questions to patients diagnosed with meningioma about their recollection of how many dental x-rays they received during their life including childhood. Also what types of x-rays they received. This type of survey is prone to a tendency of overreporting by the participant. Take my office as an example. I routinely ask a new patient if they had recent x-rays done at another office to avoid unnecessary exposure to radiation and they typically say they had a full series of x-rays, but when we request them, it turns out that they only had two or four bitewings taken.

The study also says that the risk of meningioma rises 3 times more with panoramic x-rays compared to bitewings, but in the same article the author states that panoramic equipment and digital x-rays in use today (which significantly reduce the amount of radiation exposure to the patient) were not available for the participants of the study.

Please watch a news report about the study below:











The reporter correctly describes some of the faults in the reasoning behind the study such as asking persons to recollect the types of x-rays in childhood, getting data from memory and not dental records, subjects exposed to radiation from equipment from 30 years ago. I should add that a the author of the study (I read it!) admits that most data on radiation exposure she found was from exposure to nuclear blasts(atomic bomb) and radiation therapy for cancer, both of which are so much higher than the levels of exposure for diagnostic x-rays that it is ridiculous to even mention it.

I could understand the reason to conduct a study for persons exposed to CT scans of the head and neck, as this exposes them to a higher dosage of radiation and includes the brain, but the study does not involve CT scans, instead it focuses on bitewing x-rays that we as dentists rely on to diagnose cavities. These small x-rays are highly collimated (the beam is focused to a small circle in your mouth) and does not expose the brain or tissues around it to any levels of radiation worth worrying about.

As a dentist, I cannot overemphasize the importance of taking periodic x-rays to detect caries. Those small bitewing films allow me to find decay when it is small and has not damaged the tooth to the point where there is pain or other signs. What this means to the patient is that I can fix the tooth before it reaches the point where they may need more extensive work such as a root canal or a crown.

I should also mention that while reading the x-rays for a "routine" initial examination for my patients, I have discovered cancer in the mouth that the patient was never aware of because it was small and in doing so was able to help the patient avoid the radical disfiguring surgery that would have been needed it the tumor had been allowed to grow. Maybe even saved his life...

I try to be optimistic in my thinking and I think that something good can always be found in everything. This publicity should make us (dentists) more aware of the need to tailoring our treatment to the individual patient and not tend to fall in a routine that may lead to unnecessary exposure to radiation. Dentists should use their judgement in determining how often x-rays need to be taken, as dental conditions are different for every person, and recommend these radiographs only as necessary for diagnosis and treatment of their patients.

West Palm Beach Dentist
Carlos Boudet, DDS DICOI

Website: http://www.boudetdds.com/
Implants Blog: http://www.palm-beach-implants.com/
Spanish Website: http://www.palmbeachdentist.net/

Bibliography:
1. Radiation exposure and dose evaluation in intraoral dental radiology. Radiat Prot Dosimetry (February 2007) 123(2): 262-267 first published online September 13, 2006.
2.American Cancer Society Guidelines for the Early Detection of Cancer. http://www.cancer.org/Healthy/FindCancerEarly/CancerScreeningGuidelines/american-cancer-society-guidelines-for-the-early-detection-of-cancer.
3.Ionizing radiation exposure. http://fwbmc.com/your-health/index.dot?id=642484&lang=English&db=hlt&ebscoType=healthindex&widgetTitle=EBSCO%20Health%20Library%20Index.
4. Imaging (Radiology) Tests. http://www.cancer.org/acs/groups/cid/documents/webco ntent/003177-pdf.pdf