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X-Ray Safety

X-rays help dentists diagnose common problems such as cavities, gum disease and some types of infections. They allow dentists to see inside a tooth and beneath the gums. Without them, more disease would go unchecked. Treatment would begin later. As a result, people would have more pain and lose more teeth.

The X-rays used in dental and medical offices emit extremely small doses of radiation. However, many small doses over time can damage cells. That's why experts say that X-rays should be used with caution and only when necessary.

As a patient and a parent, you can help increase X-ray safety. Talk to your dentist about how often you or your children need X-rays and why.

Learn the guidelines [LINK to "How Often Should I Get Dental X-Rays"] for how often dental X-rays should be done. Dentists are not required to follow these time intervals. Instead, they serve as a guide to make decisions about each patient. If your dentist orders more frequent X-rays, ask how they would help your treatment plan.

If you are moving and changing dental offices, ask for copies of your X-rays. Don't repeat them at your new office. Ask your dentist what techniques are used to limit your exposure to radiation.

The Primary Teeth

Less Radiation for Safer X-Rays

Several changes have reduced radiation exposure in dental X-rays through the years:

  • Lower X-ray dose — The single most important way dentists keep their patients safe from radiation is by limiting the dose. An X-ray machine is quite large, but the X-rays come out of a small cone. This limits the rays to an area less than three inches in diameter. X-ray machines also are well shielded. Very little radiation exposure occurs beyond the diameter of the beam.
  • Better film — The speed of films used for dental X-rays has been improved. The fastest speed film (F-Speed) greatly reduces the amount of radiation needed to obtain a good picture.
  • Digital X-rays — These newer X-ray machines reduce radiation by as much as 80%. It's estimated that one-third to one-half of U.S. dentists use this technology.
  • Regular inspections and licensing — State local health departments regularly check X-ray machines to make sure they are accurate and safe.
  • Lead shields — Before you get X-rays, you will be covered from the neck to the knees with a lead-lined full-body apron. Many states require these shields. They prevent radiation that bounces off the area being X-rayed from hitting your body. The amount of "scatter" radiation is very small if your dentist uses digital X-rays, or paralleling technique with F-speed film. If your child is having X-rays, make sure the apron extends all the way to the thighs to protect the genitals and reproductive organs. The American Academy of Oral and Maxillofacial Radiology recommends the use of a separate neck protector, called a thyroid collar, for patients under age 30. Children and younger adults are at greater risk for radiation-induced thyroid cancer than older adults.
  • Limited use of X-rays — Dentists take X-rays only when they believe they are necessary for an accurate dental assessment or diagnosis.

The Primary Teeth

Cone-Beam CT: 3-D Images, More Radiation

In recent years, some dentists have begun using cone-beam computed tomography (CT). These machines produce three-dimensional images of the teeth and jaw bones. Cone-beam CT exposes patients to more radiation than a standard full-mouth series of X-rays or a panoramic X-ray. Therefore, cone-beam CT should be used only where it provides a clear advantage over standard X-rays.

For selecting and placing implants, cone-beam CT is appropriate. But it is not needed for diagnosing cavities or periodontal disease. Standard X-rays also are fine for most orthodontic cases. Cone-beam CT can be useful in complex cases, however, to assist with treatment planning.

Last updated August 8, 2012