Dr. Oz Discusses Dental X-Rays And Thyroid Cancer

Posted by Dr. Todd Welch on Apr 7, 2011 in Miscellaneous

Dr. Mehmet Oz

Recently you may have heard about increased discussions via email and social media networks about the safety of dental X-rays. Much of the discussion stems from an unnamed individual who referenced a Dr. Oz show that aired “last Wed” advising women to ask for a thyroid collar when receiving a mammogram or dental x-ray to reduce radiation exposure. The individual encouraged people to share this information, and it has been spreading through social media networks and via email.

It is possible the individual is referring to a Dr. Oz program that actually aired Sept. 28, 2010. The episode focused on thyroid cancer, and during a portion of the show, Dr. Oz promoted the use of protective leaded aprons and thyroid collars to reduce radiation exposure, a practice the ADA recommends in The Selection of Patients for Dental Radiographic Examinations developed by the ADA and the U.S. Food and Drug Administration.

While the ADA believes the radiation exposure from dental X-rays is low relative to other sources, every precaution should be taken to ensure that radiation exposure is as low as reasonably achievable (the ALARA principle). The ADA recommends that dentists use lead aprons and leaded thyroid collars (or non-lead equivalents) whenever possible. This practice is strongly recommended for children, women of childbearing age and pregnant women who are especially susceptible to radiation effects.

Lead Apron With Thryoid Collar

The ADA also recommends conducting a thorough clinical examination, considering the patient’s history, reviewing any prior X-rays, performing a caries risk assessment and considering both the dental and the general health needs of the patient prior to taking any X-rays. When x-rays are necessary, the ADA recommends that dentists use the fastest imaging receptor and use a rectangular collimator. There is no recommended frequency for panoramic radiograph or full-mouth surveys. The only imaging examination with a frequency recommendation is the bitewing—its frequency is based on an assessment of the patient’s caries risk.

The following discussion points and links to resources may be helpful in talking with patients about the issue of x-ray safety:

Discussion Points:

Many oral diseases can’t be detected on the basis of a visual and tactile examination alone. Dental X-ray exams are valuable in providing information about your oral health such as early stage cavities, gum diseases, abscesses or some types of tumors. X-rays can help dentists catch and treat oral health problems at an early stage.
How often dental X-rays should be taken depends on your oral health condition, your age, your risk for disease and any signs and symptoms of oral disease you may be experiencing. Let’s talk about what is right for you.

How Do Dental X-rays Compare To Other Sources Of Radiation

The amount of radiation that we are exposed to from dental X-rays is very small compared to our daily exposure from things like, cosmic radiation and naturally-occurring radioactive elements (for example, those producing radon).

The table below compares our estimated exposure to radiation from dental X-ray with other various sources. As indicated below, a millisievert (mSv) is a unit of measure that allows for some comparison between radiation sources that expose the entire body (such as natural background radiation) and those that only expose a portion of the body (such as X-rays).

Source	Estimated Exposure (mSv)
Man MadeDental X-rays Bitewing radiographs Full-mouth series	0.038 0.150
Medical X-raysLower gastrointestinal tract radiography Upper gastrointestinal tract radiography Chest radiograph	4.060 2.440 0.080
NaturalCosmic (Outer Space) Radiation Average radiation from outer space In Denver, CO (per year)	0.510
Earth and Atmospheric RadiationAverage radiation in the U.S. from Natural sources (per year)	3.000

Source: Adapted from Frederiksen NL. X-Rays: What is the Risk? Texas Dental Journal. 1995;112(2):68-72.

Recently, a physician with the American Cancer Society posted a detailed discussion about thyroid cancer on a CNN blog and noted the ADA guidelines for the use of leaded aprons and thyroid collars. Here is an excerpt from the article:

The thyroid is a gland in the neck below and in front of the throat. It secretes hormones that control metabolism. People with low thyroid function gain weight and are lethargic. Those with an overactive thyroid have weight loss and can experience nervousness and other problems. The American Cancer Society estimates that 44,670 new cases of thyroid cancer occurred in 2010 (33,930 in women, and 10,740 in men). Thyroid cancer caused about 1,690 deaths (960 women and 730 men). Thyroid cancer is different from many other adult cancers in that it is commonly diagnosed in younger people. Nearly two of three cases are found in people between the ages of 20 and 55.

Dental X-rays give a very low dose of radiation to the mouth. There is some scatter of radiation and the potential for some radiation absorption by the nearby thyroid and other organs. The American Dental Association notes that a leaded apron placed over the torso minimizes radiation exposure to the chest and abdomen and should be used when any dental X-ray is taken. The group also notes that a leaded thyroid collar can protect the thyroid from radiation and should be used whenever possible.

While the experts that I consulted do recommend use of a thyroid collar, none of the experts was especially worried that dental X-rays are a significant cause of thyroid cancer. There is however significant concern that radiation from other forms of medical testing may be causing some thyroid cancers. CT scanning is the medical procedure that concerns experts the most. It uses higher levels of radiation than conventional X-rays and much higher levels of radiation than are used in dental X-rays.

Lead Apron With Thryoid Collar

Conclusion:

Dental X-ray examinations provide valuable information that helps your dentist evaluate your oral health. With the help of radiographs (the term for pictures taken with X-rays), your dentist can look at what is happening beneath the surface of your teeth and gums. If you have questions about your dental X-ray exam, talk with your dentist. So let’s please put this internet rumor to bed. We now have very complete information on patient radiation doses from dental x rays. They are among the lowest radiation dose exams of any diagnostic radiologic procedure in the healing arts. Current practices deliver patient doses from a full-mouth series of intraoral films (usually 14-18 films) that are less than what a person receives in a month from natural environmental sources (commonly called background exposure). Doses from bitewing or panoramic films are even less. New technology, such as digital dental x-rays, is reducing the doses still further.

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Thanks for Reading !!