General Dental Information
and Education Page
Are dental X-rays necessary? Yes, they often provide
information essential for detection, diagnosis, and treatment of
conditions that can threaten your oral and general health.
Many diseases of the teeth and surrounding tissues cannot be seen
when your dentist examines your mouth. If X-rays are not used, small
cavities between teeth, abscesses, cysts, tumors, and other diseases
may be impossible to detect until obvious signs and symptoms have
developed and serious damage has been done to your health.
Your dentist will first review your history, examine your mouth,
and then decide whether you need X-rays. If you are a new patient,
the dentist may ask you to have complete X-rays to determine the
present health of your mouth. Afterwards, you may need X-rays only
when information is needed about a particular problem. Children
may need X-rays taken more often (every 6 months) than adults because
their teeth and jaws are still developing.
If possible X-rays from your previous dentist should be sent to
your new dentist. Sometimes your new dentist can use earlier X-rays
to evaluate changes that have taken place in your mouth.
If I am pregnant or think I may be pregnant, should dental X-rays
be postponed? Not necessarily. Tell your dentist that you are, or
think you may be, pregnant. When a pregnant woman wears a leaded
apron during dental X-rays it is unlikely that the developing baby
receives any detectable radiation from outside the body.
What are the different types of X-rays:
- Bitewing- These show the crowns of several upper and lower teeth
on one small film. This type of X-ray is especially useful for
showing cavities between teeth and changes in bone caused by periodontal
- Periapical- This X-ray shows entire teeth, including all of
the roots and surrounding tissues on one small film. These X-rays
show many kinds of disorders, including impacted teeth, fractures,
abscesses, cysts, tumors.
- Full-mouth series- This is a complete set of bitewing and periapical
X-rays that show all of the teeth, roots, and related areas of
the jaws. The number of pictures taken varies depending on the
size and shape of the mouth and teeth. Generally, at least 18
X-ray pictures are needed, but a full-mouth series may consist
of as few as 6 or as many as 21.
- Panoramic- A panoramic view X-ray shows all the upper and lower
teeth, large portions of the jaws and other structures in one
large picture. It is often used to find unerupted teeth, cysts,
fractures, retained root fragments, and other conditions of the
jaw. It does not generally show enough detail to be useful for
detection of decay and bone loss from periodontal disease.
- Cephalometric- These X-rays are sometimes called headfilms.
They show all of the bones of the face and skull. This type of
X-ray is used to evaluate growth, development, and skeletal relationships.
There is a lot of confusion and concern about the radiation from
dental radiographs. People are exposed to natural background radiation
all their lives. This radiation comes primarily from outer space
(cosmic radiation) and secondarily from naturally radioactive substances
in the earth's surface. It has been estimated that the average person
receives about 80 millirem (mrem) of radiation every year. Natural
background radiation cannot be directly compared to X-ray examinations,
however, because background radiation affects the entire body continuously,
while diagnostic X-rays affect only a small part of the body for
a very short time.
Exposure to large amounts of X-radiation is harmful. But with modern
techniques and equipment, the amount of radiation received in a
dental examination is extremely small, so small in fact that most
states no longer regular dental radiography. The new digital radiograph
systems produce less than 1/5 the radiation that the older film
systems use. In our office we us the Shick
Digital Radiograph system. The other factor is the type of tissue
exposed to radiation. Radiation damage is mostly only a consideration
with rapidly dividing tissues such as reproductive organs, bone
marrow, etc. The tissues exposed to dental x-rays (teeth, jaw, cheeks)
are not as susceptible to radiation damage. Therefore, the risk
of harmful effects from dental X-rays is negligible.
It is difficult to determine whether small doses of X-rays increase
the individual patient's risk of cancer because enormous numbers
of people would have to be studied for long periods of time. However,
the chances are extremely small that dental X-rays contribute to
cancer, because the exposure of the tissues of the head and neck
is so small. Even so, X-ray examinations should be made only when