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 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, tumours, 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 show problems such as impacted teeth, bone abnormalities, cysts, solid growths (tumours), infections, and fractures.
- Digital X-rays can be sent to a computer to be recorded and saved.
A full-mouth series of periapical X-rays (about 14 to 21 X-ray films) is 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 (tumours), 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. Dental X-rays are scheduled when you need them based on your age, risk of disease, and signs of disease.
How To Prepare
Before the X-ray test, tell your doctor if you are or might be pregnant. If you have an X-ray, he or she will have you wear a lead apron over your belly to protect your baby from the X-rays.
You do not need to do anything else 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. The technician can cover your neck with the collar of the apron (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.
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.
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.
The amount of radiation used in dental X-rays is low. But there is always a slight risk of damage to cells or tissue from being exposed to any radiation, including the low levels of radiation used for this test. But the risk of damage from the X-rays is usually very low compared with the potential benefits of the test.
Dental X-rays are safe during pregnancy. So most dental work can be done while you are pregnant. Delaying dental care can make a problem worse.
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.
No tooth decay is seen.
No damage to the bones supporting the teeth is seen.
No dental injuries, such as tooth or jaw fractures, are seen.
No extra or impacted teeth are seen and no teeth are out of their normal place.
Tooth decay is seen.
Damage to the bones supporting the teeth is seen.
Dental injuries, such as tooth or jaw fractures, are seen.
Cysts, solid growths (tumours), or abscesses are seen.
Abnormally placed, extra, or impacted teeth are seen.
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 can't 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
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.
Other Works Consulted
- American Dental Association Council on Scientific Affairs (2006). The use of dental radiographs: Update and recommendations. Journal of the American Dental Association, 137(9): 1304–1312.
- Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
Current as of: March 25, 2020
Author: Healthwise Staff
Patrice Burgess MD - Family Medicine
Anne C. Poinier MD - Internal Medicine
Adam Husney MD - Family Medicine
Martin J. Gabica MD - Family Medicine
Kathleen Romito MD - Family Medicine
Steven K. Patterson BS, DDS, MPH - Dentistry
Current as of: March 25, 2020