How Much Radiation Do You Get From Dental X-Rays?
According to the American Nuclear Society, this is how much radiation you expect from common activities:
620 mrem/year = the average level of radiation per person in the US
50000 mrem/year = the safe allowable dose for people that are exposed to radiation in their wok
1 mrem = two hours in a jet plane
7 mrem/year = from living in a brick house
10 mrem/year = cooking with natural gas
2 mrem/year = from sleeping next to someone else
36 mrem/year = from smoking one pack of cigarettes a day
42 mrem = breast mammogram per breast
700 mrem = abdominal x-ray
63 mrem/year = living in the Colorado Plateau area
0.5 mrem = one dental x-ray
The amount of radiation (mrem) that a patient receives during dental x-rays is very small when compared to other sources of radiation in everyday life. In addition, our office uses modern digital x-rays. The amount of radiation received from a digital x-ray can decrease up to another 80%. That means while a standard x-ray gives off 0.5 mrem, a digital x-ray can give off as little as 0.1 mrem.
Why are x-rays needed? During a standard exam, the dentist is able to examine only visible surfaces of the teeth and soft tissue. X-rays allow the dentist to see small cavities that are developing in between the teeth. Once these areas have become visible in the mouth, typically the tooth may already be to the point where it needs a crown, root canal, or may even need to be extracted. Routine films allow us to diagnose small cavities and stop them before they become bigger and more costly problems. Additionally, x-rays allow the dentist to examine the mandible and maxilla for any unusual growths or abnormalities. While cancer and tumors of the jaw are rare, the prognosis is always better the earlier you treat these areas.
While digital x-rays do emit a very small amount of radiation, it is clear that the benefits greatly outweigh any minimal risks.
How Much Radiation Do You Get From Dental X-Rays?
By Steve D. Rima, CHP
Just the mention of the word “radiation” conjures up an unpleasant image for most people. We associate it with bombs, cancer, and all manner of other bad things. But do you know that there are many beneficial uses of radiation? One type of radiation, x-rays, are used extensively in the medical and dental professions to diagnose and treat a wide variety of conditions.
Just how much radiation do you get from a dental x-ray and how harmful is it? First, let’s talk about what an x-ray is. X-rays are energy in the form of waves, identical to visible light. In fact, the only difference between light and x-rays is that light doesn’t have enough energy to go through your body and x-rays do. Both can make an image on photographic film, so both types of energy are used to make pictures; light makes photographs of the “outside” of objects, x-rays make pictures of the “inside” of objects, including your body.
A unit called a “rem” is used to measure radiation. A rem is a large unit, much like a mile is a large unit of length, so we usually use a millirem (mrem) instead, much as you would measure in inches instead of miles for most purposes. (It takes 1000 mrem to equal one rem.)
Advances in x-ray equipment, especially film technology, allow your dentist to get a good x-ray image using much less radiation than was previously required. A typical dental x-ray image exposes you to only about 2 or 3 mrem. The National Council on Radiation Protection (NCRP) says that the average resident of the U.S. receives about 360 mrem every year from background sources. This comes from outer space, radioactive materials in the earth, and small amounts of radioactive material in most foods we consume.
Some typical sources that may expose you to radiation also include smoke detectors (less than 1 mrem per year), living in a brick house instead of a wood one (about 10 mrem per year due to radioactive materials in the masonry), cooking with natural gas (about 10 mrem per year from radon gas in the natural gas supply), reading a book for 3 hours per day (about 1 mrem per year due to small amounts of radioactive materials in the wood used to make the paper), and even from flying in an airplane (about 5 mrem for one cross-country flight because of the increased altitude.) In fact, you receive about 2 mrem per year from sleeping next to someone! This is because all of us have very small amounts of naturally occurring radioactive materials in our bodies.
Obviously, you probably would not refuse to fly on an airplane, live in a brick house, read books, live without smoke detectors, or sleep with your spouse because of the small amount of radiation you receive from these activities. Since your dentist gains valuable information from x-rays to aid you in keeping healthy teeth, it is also not in your best interest to refuse dental x-rays because of the very small amount of radiation you receive from them.