Dental X-rays

Test Overview

Dental X-rays are pictures of the teeth, bones, and soft tissues around them to help find problems with the teeth, mouth, and jaw. X-ray pictures can show cavities, hidden dental structures (such as wisdom teeth), and bone loss that cannot be seen during a visual examination. Dental X-rays may also be done as follow-up after dental treatments.

The following types of dental X-rays are commonly used. The X-rays use small amounts of radiation.

• Bitewing X-rays show the upper and lower back teeth and how the teeth touch each other in a single view. These X-rays are used to check for decay between the teeth and to show how well the upper and lower teeth line up. They also show bone loss when severe gum disease or a dental infection is present.
• Periapical X-rays show the entire tooth, from the exposed crown to the end of the root and the bones that support the tooth. These X-rays are used to find dental problems below the gum line or in the jaw, such as impacted teeth, abscesses, cysts, tumors, and bone changes linked to some diseases.
• Occlusal X-rays show the roof or floor of the mouth and are used to find extra teeth, teeth that have not yet broken through the gums, jaw fractures, a cleft in the roof of the mouth (cleft palate), cysts, abscesses, or growths. Occlusal X-rays may also be used to find a foreign object.
• Panoramic X-rays show a broad view of the jaws, teeth, sinuses, nasal area, and temporomandibular (jaw) joints. These X-rays do not find cavities. These X-rays do show problems such as impacted teeth, bone abnormalities, cysts, solid growths (tumors), infections, and fractures.
• Digital X-ray is a new method being used in some dental offices. A small sensor unit sends pictures to a computer to be recorded and saved.

A full-mouth series of periapical X-rays (about 14 to 21 X-ray films) are most often done during a person's first visit to the dentist. Bitewing X-rays are used during checkups to look for tooth decay. Panoramic X-rays may be used occasionally. Dental X-rays are scheduled when you need them based on your age, risk for disease, and signs of disease.

Why It Is Done

Dental X-rays are done to:

• Find problems in the mouth such as tooth decay, damage to the bones supporting the teeth, and dental injuries (such as broken tooth roots). Dental X-rays are often done to find these problems early, before any symptoms are present.
• Find teeth that are not in the right place or do not break through the gum properly. Teeth that are too crowded to break through the gums are called impacted.
• Find cysts, solid growths (tumors), or abscesses.
• Check for the location of permanent teeth growing in the jaw in children who still have their primary (or baby) teeth.
• Plan treatment for large or extensive cavities, root canal surgery, placement of dental implants, and difficult tooth removals.
• Plan treatment of teeth that are not lined up straight (orthodontic treatment).

Without X-rays, dentists may miss the early stages of decay between teeth.

How To Prepare

Before the X-ray test, tell your doctor if you are or might be pregnant. Dental X-rays are only done on your mouth area, but if you are pregnant, routine dental X-rays may be postponed so you do not have any radiation to your baby (fetus). If dental X-rays are absolutely needed, a lead apron will be placed over your belly to shield your baby from the X-rays.

You do not need to do anything before having a dental X-ray.

How It Is Done

Dental X-rays are taken in the dentist's office. The X-ray pictures are read by your dentist.

• A dental technician will cover you with a heavy lead apron as you sit upright in a chair. This apron shields your body from X-rays. Modern lead aprons have a collar (called a thyroid shield) to shield the thyroid gland from radiation.
• Everyone else in the room wears a protective apron or stays behind a protective shield.
• The dental technician will have you bite down on a small piece of cardboard or plastic. The cardboard or plastic holds X-ray film. You may do this several times to get pictures of all your teeth. Some X-ray machines have a camera that circles your head and takes pictures of your teeth while you sit or stand.
• You may want to rinse your mouth before and after the X-rays.

How It Feels

X-rays take only a few minutes and are not painful.

Some people may gag on the plastic or cardboard that holds the X-ray film. People often find it easier to relax if they focus on something else (such as an object on the wall) and take slow, deep breaths through their nose during the X-rays.

Risks

Radiation used in dental X-rays is so low that there is very little chance of problems from having the X-rays.

Pregnant women may not want to have routine dental X-rays taken until after they give birth. Although there is no proof that a routine dental X-ray could harm a developing baby (fetus), dentists usually suggest you wait to have your X-rays until after the baby is born. Delaying the X-ray for a few months will not result in further harm to teeth in most cases. There are times when the severity of the dental problem requires an X-ray to deal with an urgent concern.

Results

Dental X-rays are pictures of the teeth, bones, and soft tissues around them to help find problems with the teeth, mouth, and jaw. Your dentist can talk to you about your X-rays right after they are done.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• If you cannot stay still or hold the X-ray plastic or cardboard in your teeth.
• If you have braces, retainers, dentures, bridges, and certain body piercings (ear, tongue, lip, cheek, or nose).

What To Think About

• Dental X-ray equipment is safe and uses very little radiation. States often have strict regulations and inspection procedures to check the safety of X-rays and X-ray equipment. Oral health professionals are taught to take high-quality X-rays with a small amount of radiation exposure to you.
• If you are going to a new dentist, have your other dentist send copies of your dental X-rays to your new dentist. You may not need any more X-rays with your new dentist.
• The following U.S. Food and Drug Administration (FDA) dental X-ray guidelines are for people who have no tooth decay and are not at high risk of getting cavities:
  • Adults should have bitewing X-rays every 2 to 3 years.
  • Teens should have bitewing X-rays every 1½ to 3 years.
  • Children should have bitewing X-rays every 1 to 2 years.
• The following FDA guidelines are for people who have tooth decay or are at high risk of getting cavities:
  • Adults should have bitewing X-rays every 1 to 1½ years.
  • Teens should have bitewing X-rays every 6 to 12 months until no tooth decay is seen.
  • Children should have bitewing X-rays every 6 months until no tooth decay is seen.
• Many dentists think that all adults should have a panoramic X-ray every 2 to 5 years to check for mouth and teeth problems.
• Some dentists use digital radiography. This method uses an electronic sensor instead of X-ray film. An electronic image is taken and stored in a computer. This image can be viewed on a computer screen. Less radiation is needed to make an image with digital radiography than with standard dental X-rays.

References

Other Works Consulted

• Fejerskov O, Kidd E (2003). Dental Caries: The Disease and Its Clinical Management. Oxford: Blackwell Munksgaard.

• Harris NO, Garcia-Godoy F, eds. (2004). Primary Preventive Dentistry, 6th ed. Upper Saddle River, NJ: Pearson/Prentice Hall.

Credits