Posts for tag: x-rays
One of the most widely used forms of dental imaging is the bitewing x-ray. So called because of the shape of the device that holds the exposable film a patient clenches between their back teeth, the bitewing x-ray is an effective means for detecting the earliest stages of tooth decay.
These early signs are small lesions on a tooth surface caused by mineral loss in the enamel. While we can identify them on front teeth through visual examination or bright lighting, they’re nearly impossible to see on the biting surfaces of back teeth. The bitewing x-ray solves this problem.
During the procedure, a narrow beam of x-rays is directed at the back teeth area. Since X-rays can transmit through solid matter, they pass through the teeth and gums to expose the film attached to the bitewing assembly.
X-rays pass through matter at different rates depending on the density of the tissue — a slower rate for harder tissues like teeth and bone and a faster rate for soft tissues like the gums. As a result, x-rays through teeth expose less of the film and appear as a lighter image than the gums. This difference is so precise even a tooth’s softer dentin appears slighter darker than its harder outer enamel.
This precision helps us identify decay lesions. Because the lesions on the enamel are less dense than the normal enamel, they’ll appear as dark spots. By detecting them at this stage we have a better chance for reversing the effects of decay or at least minimizing damage that’s already occurred.
Because x-rays emit radiation, there’s a natural concern about over-exposure and we go to great lengths to reduce it. Children may undergo a bitewing x-ray twice a year for developing teeth, while adults with healthy teeth are typically x-rayed just once a year. Advances in digital film and other technology have also helped lower the exposure rate.
Today’s standard 4-film bitewing x-ray produces about four days worth of what we receive on average from normal background radiation, so the health risk is quite negligible. The benefit, on the other hand, is much greater — the early detection of tooth decay could ultimately save a tooth.
Your dental care would be much more limited without our ability to see “below the surface” with x-ray imaging. But since x-rays passing through the body are a form of radiation, could your exposure from them be hazardous to your health?
It depends on exposure dosages and, of course, the amount you have been exposed to over your lifetime. But, decades of research have demonstrated that exposure to dental x-rays during your regular office visits are only a fraction of the radiation you normally encounter from the natural environment every year.
X-rays have the ability to pass through body tissues, but at different rates for soft tissue like skin and muscle and hard tissue like bone. This effect creates shadows on exposed film; the differentiation is in such detail that a trained technician can interpret not only internal structures, but defects such as fractured bone or, in the case of dentistry, signs of tooth decay and bone loss from gum disease.
But like other energy sources in our environment, x-rays do emit radiation that in high doses can be dangerous to living tissue. The amount of exposure is measured in millisieverts (mSv), a unit that allows for comparison of doses from different sources of radiation. Scientists have calculated that we’re normally exposed to between 2 and 4.5 mSv every year.
By contrast, a single digital periapical image taken of a tooth is equal to 1 microsievert (μSv), or one thousandth of an mSv; a full mouth series (between 18 and 20 images) creates an exposure of 85 μSv, or 85/1000 of one mSv. In addition, advances in technology have further reduced the radiation exposure from x-ray imaging. For example, digital imaging has reduced exposure during full mouth x-rays from seven to ten days of equal exposure from normal background radiation to half a day, and with no loss in image quality.
In effect, dental x-rays pose little to no risk for patients. Still, understanding that x-ray imaging does expose patients to radiation, dentists follow certain protocols and safety precautions. For example, dentists will place a lead apron around their patients’ chest area during an x-ray exposure.
As your dentist, we’re happy to address any concerns you may have about x-ray radiation exposure. But rest assured, the x-ray devices used in your dental care, so necessary in the fight against tooth decay and other diseases, are safe and reliable.
If you would like more information on the use of x-ray technology and safety, please contact us or schedule an appointment for a consultation. You can also learn more about this topic by reading the Dear Doctor magazine article “X-Ray Frequency and Safety.”
Yes, dental x-rays are a safe and vital tool we use for measuring and monitoring your oral health. We feel it is imperative to ensure that our patients have the facts — especially when it comes to their oral healthcare. This is why we want to respond to this important question about the safety of dental x-rays.
We want you to know what they are, how they are used, what makes them a safe and effective tool, and why they are so important to dentistry and your health. X-rays are a form of electromagnetic radiation, in fact, just like natural daylight, except they have a much shorter wavelength. And because they are a form of ionizing radiation, they can easily penetrate bodily tissues without causing any harm when used properly. The reasons we use them are obvious; they help us literally see what is unseen. For example, they enable us to see bone structure and roots of teeth among other things, and are commonly used for diagnosing tooth decay. Furthermore, today's x-ray machines and other image capturing techniques are so sophisticated and sensitive that the amount of radiation required for diagnosis is almost nothing when compared to what you get from the background radiation present in everyday living. In fact, the average single digital periapical (“peri” – around; “apical” – root end of a tooth) film is equal to 1/10 the amount of everyday natural environmental exposure. These facts make it clear that dental x-rays are completely safe and, thus, are nothing you need to be concerned about.