X-rays are one of the most useful medical inventions of the 21st century.
They allow doctors to spot broken bones, cancerous tissues, and other dangerous conditions, and they allow dentists to view hidden surfaces of the teeth that can’t be seen by the naked eye.
However, many dental patients express concern about the radiation levels emitted by X-rays. Even though most dentistry professionals agree that these levels are so low that they are worth the benefit of improved dental care, many patients and parents still wonder if dental X-rays are safe.
Here, we’ll discuss the precise risks associated with dental X-rays, so that each patient can make an informed, educated decision about his or her health.
How Much Radiation is in Dental X-rays?
X-rays work by emitting a form of radiation called electromagnetic waves. Different tissues in the body absorb different amounts of radiation, causing them to appear white, gray, or black in the X-ray film. The calcium in bones absorbs the most radiation, so bones appear white. Fats and other tissues absorb less, and so appear gray. This is what allows doctors and dentists to spot abnormal conditions such as tumors.
There are two main types of dental X-rays: bitewing X-rays, in which the patient bites down on the X-ray film, and panoramic X-rays, in which a machine rotates around the patient’s cranium to create a complete image of the teeth.
During a routine cleaning exam, most patients will receive 4 bitewing X-rays, one for each set of molars. If the dentist is using digital dental film, the patient will receive about 10 micro-Sieverts of radiation. If the dentist uses traditional dental film, more radiation will be needed and the patient will receive about 22 micro-Sieverts. By comparison, the average American receives about 9 micro-Sieverts per day (we’ll discuss this in more detail below).
A panoramic X-ray releases about 26 micro-Sieverts of radiation, depending on the machinery used and other factors.
How Much Radiation are we Exposed to Every Day?
The term “radiation” is very scary. It conjures to mind images of melted Chernobyl factories and other destruction. But like many other minerals and chemicals which are dangerous in large amounts, radiation is constantly present in our natural environment. All humans are exposed to daily trace amounts of radiation, from the sun, natural gas, and other sources.
Cosmic radiation constantly rains down on us from our atmosphere, and certain elements on Earth are constantly generating a stream of radioactive particles beneath our feet. Since our atmosphere protects us from most cosmic radiation, those who travel frequently by plane or live in high altitudes are especially prone to radiation exposure. There is radiation in the food we eat, and in the natural gas we use to cook it. Then, of course, there is the radiation we receive from using microwaves, cell phones, and other man-made gadgets.
When all is said and done, the average human receives between 3,500 and 4,000 micro-Sieverts of radiation each year. By the end of this day, you will have received about 10 micro-Sieverts of radiation—the same amount you are exposed to in one normal dental X-ray.
How Many Dental X-rays Should I Have Each Year?
This question does not have a simple answer. Each patient and circumstance is different, and the amount of X-rays you should take depends on factors such as how much dental work you have had, the current condition of your teeth, and whether or not you are displaying any symptoms of gum disease. Your dentist may determine that a few moments’ exposure to radiation is better for your overall long-term health than potentially failing to spot an infection, abscess, or hairline fracture.
A good dentist will always practice a radiation safety principle called ALARA, or “As Low as Reasonably Achievable.” This simply means that your dentist will prescribe only the radiation that is medically necessary for your long-term health. If your dentist has decided to take an X-ray, it means that he or she has determined that the benefits of the X-ray outweigh the risks.
The American Dental Association suggests that X-rays be taken every 1-2 years for children and teens, and every 2-3 years for adults. However, these are only guidelines. A dentist’s decision to take X-rays should always be patient-specific and risk-based. That way, the dentist can use his or her best professional judgement to determine if an X-ray is truly necessary.
Making an Educated Decision about X-rays
Most medical organizations feel that as long dentists provide lead aprons and/or lead collars, dental X-rays do not pose a serious risk. However, if you are still concerned about the health risks of X-rays, it is always your prerogative to refuse care.
It may also help you to discuss the risks and benefits of X-rays with your dentist. As him or her how X-rays will impact your care, what specific machinery the dentistry uses, and whether or not X-rays are truly necessary for your specific situation. Never be afraid to ask your dentist questions, so that you can make as informed and educated a decision as possible.