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

Dental X-rays- Do They Cause Thyroid Cancer?

Do dentists take too many x-rays, and can these cause thyroid cancer?

I't incredible how much influence can a popular show like Oprah have on their audience.

Dr. Mehmet Oz said that thyroid cancer was “the fastest-growing cancer in women” and cited the harmful effects of radiation from sources like dental X-rays and mammograms.

Here are some facts for you to consider:

X-rays are one type of radiation, and radiation is absorbed by our tissues as it passes through them.

Small amounts of radiation absorbed by the tissues have not been shown to cause harm, but large amounts or prolonged exposure can cause tissue changes such as cell death, mutations and cancer.

Radiation effects are cumulative, so in theory low doses over time could add up to a cancer risk.

The number of thyroid cancers diagnosed have increased a lot in recent years. The number of diagnoses in women nearly doubled from 2000 to 2008.

Dr. Otis W. Brawley, chief medical officer of the American Cancer Society, said in an interview “Our technology has gotten so good that we are finding cancers today that even 15 years ago would not have been diagnosed,” “We’re finding and treating cancers that would never have killed anyone.”

This increase in cancer rate is due to improved cancer detection and not from a higher number of cancers developing.

If you think about it, you realize that this last statement is correct, since the incidence of thyroid cancer in women over the age of 50 has not increased more than any other age group, even though this group gets mamograms frequently and younger women do not.

Dental X-rays are also unreasonably suspected for the rise in thyroid cancer.

In recent years the emphasis has been in using less radiation and faster film. Many dentists are using panoramic radiographs which give much more information than the full intraoral series of films with less radiation.
Lastly, the implementation of digital radiography in modern dental offices further reduces the level of radiation exposure to the patients when compared to conventional x-ray film.
Dr. Oz warned that people who have more than five X-rays a year have a fourfold greater risk of developing this cancer, but there is no scientific evidence to back up that statement.

So what can we do to make sure that we minimize the risks associated with exposure to xrays in medical or dental offices?

If you need a dentist in west palm beach that is aware of these concerns here are some suggestions:

1 -Ask your doctor the reason why you need those particular x-rays and also the consequences of not getting them.
2 -Request a thyroid shield if one is not automatically placed for you.
3 -Digital x-rays are excellent at significantly reducing radiation as much as 50% compared to conventional x-ray film, so dentists should invest in digital radiography.
4 -Dentists should use good clinical judgement to determine the frequency that dental radiographs should be taken, so that a person with a low incidence of caries and or periodontal problems can have x-rays taken at longer intervals than a person with a high caries rate.

I hope this article provides enough information to ease your fears about dental x-ray exposure in the dental office.

Modern dentistry relies on the use of these diagnostic x-rays to detect problems early, when they can be fixed easily and inexpensively. Refusing to get the necessary x-rays would result in problems that are undetected until the damage is extensive and requires expensive dental work.

Carlos Boudet, DDS, DICOI
Website: http://www.boudetdds.com/
Implants Blog: http://www.palm-beach-implants.com/
Spanish Website: http://www.palmbeachdentist.net/


References:
1 Dr. Otis Brawley, Chief medical officer American Cancer Societyhttp://www.cnn.com/2011/HEALTH/expert.q.a/03/30/thyroid.cancer.radiation.brawley/index.html 2 Dr. Leonard Wartofsky, Chairman, Department of Medicine, Washington Hospital
Center,Professor of Medicine, GeorgetownUniversity School of Medicine, Washington, D.C., USAhttp://hormones.gr/pdf/103-108.pdf
3 Researchers Examine Long-term Risks of Exposure to Medical Radiation, Journal of the
American Medical Association, JAMA. 2006;296(6):638-640. doi: 10.1001/jama.296.6.638
4 Radiation Exposure and Thyroid Cancer,JAMA. 2006;296(5):513. doi: 10.1001/jama.296.5.513