X-ray - teeth

Alternative names
Dental X-rays


Dental X-rays are a type of picture of the teeth and mouth. X-rays are a form of electromagnetic radiation, just like visible light. They are of higher energy, however, and can penetrate the body to form an image on film.

Structures that are dense (such as silver fillings or metal restoration) will block most of the photons and will appear white on developed film. Structures containing air will be black on film, and teeth, tissue, and fluid will appear as shades of gray.

How the test is performed

The test is performed in the dentist’s office. The most common procedure is a bite-wing, where a small piece of film is placed in the mouth behind a section of the teeth. You are asked to bite down on the paper tab around the film, which holds the film in place.

The X-ray machine is aimed at that section of teeth, and a picture is taken. Most dental X-rays include four or more views of the teeth.

How to prepare for the test
There is no special preparation.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child’s age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child’s age:

  • Infant test or procedure preparation (birth to 1 year)  
  • Toddler test or procedure preparation (1 to 3 years)  
  • Preschooler test or procedure preparation (3 to 6 years)  
  • Schoolage test or procedure preparation (6 to 12 years)  
  • Adolescent test or procedure preparation (12 to 18 years)

Notify the dentist if you are pregnant.

How the test will feel
The X-ray itself causes no discomfort. Some people find that biting on the piece of film makes them gag; slow, deep breathing through the nose usually relieves this feeling.

Why the test is performed
Dental X-rays are useful in the diagnosis of dental diseases and injury.

Normal Values
Normal number, structure, and position of the teeth and jaw bones. No cavities or other abnormalities.

What abnormal results mean
Dental X-rays may be used to identify the following:

  • The number, size, and position of teeth  
  • Unemerged or impacted teeth  
  • The presence and extent of dental caries  
  • Bone damage (such as from periodontitis)  
  • Abscessed teeth  
  • Fractured jaw  
  • Malocclusion of teeth  
  • Other abnormalities of the teeth and jaw bones

What the risks are
There is very low radiation exposure. However, no one should receive more radiation than necessary. A lead apron can be used to cover the body to reduce radiation exposure, especially for women who are or may be pregnant.

Special considerations
Dental X-rays can reveal Tooth decay (cavities) before they are visible even to the dentist. Many dentists will take yearly bite-wings to catch the early development of cavities.

Johns Hopkins patient information

Last revised: December 3, 2012
by Levon Ter-Markosyan, D.M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.