Low Radiation Dentistry
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.
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.
- 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
- 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
- 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.
Why It Is Done
Dental X-rays are done to:
Without X-rays, dentists may miss the early stages of decay between teeth.
- 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).
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.
How It Feels
- 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.
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.
Radiation used in dental X-rays is so low that there is very little chance of problems from having
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.
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
- 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 cysts, solid growths (tumors), or abscesses are seen
- No extra or impacted teeth are seen and no teeth are out of their normal
- 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 (tumors), 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:
What To Think About
- 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)
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
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:
The following FDA guidelines are for people who have tooth decay or are at high risk of getting
- 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.
Many dentists think that all adults should have a panoramic X-ray every 2 to 5 years to check for
mouth and teeth problems.
- 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.
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.