Dental x-rays

Definition

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. There are 2 types of x-rays: bite-wing and periapical.  The bite-wing is when the patient bites on a paper tab and shows the crown portions of the top and bottom teeth together. The periapical shows one or two complete teeth from crown to root.  In addition, there is a method of x-ray called digital that many dentists are using now.  The image runs through a computer and the amount of radiation transmitted during the procedure is less than traditional methods.

The x-ray machine is aimed at one section of teeth when 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. 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 help diagnose disease and injury of the teeth and gums. 

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 (cavities)
• 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 dental cavities (tooth decay) before they are visible even to the dentist. Many dentists will take yearly bite-wings to catch the early development of cavities.

Illustrations

Tooth anatomy

Development of baby teeth

Development of permanent teeth

Page Content:

X-ray - teeth ; tooth x rays; wisdom tooth x rays