There are two main types of dental X-rays: intraoral (meaning the X-ray film is inside the mouth) and extraoral (meaning the X-ray film is outside the mouth).
- Intraoral X-rays are the most common type of dental X-ray taken. These X-rays provide a lot of detail and allow your dentist to find cavities, check the health of the tooth root and bone surrounding the tooth, check the status of developing teeth, and monitor the general health of your teeth and jawbone.
- Extraoral X-rays show teeth, but their main focus is the jaw and skull. These X-rays do not provide the detail found with intraoral X-rays and therefore are not used for detecting cavities or for identifying problems with individual teeth. Instead, extraoral X-rays are used to look for impacted teeth, monitor growth and development of the jaws in relation to the teeth, and to identify potential problems between teeth and jaws and the temporomandibular joint (TMJ, see document, "Temporomandibular disorders" for more information) or other bones of the face.
Types of Intraoral X-Rays
There are several types of intraoral X-rays, each of which shows different aspects of teeth.
- Bite-wing X-rays show details of the upper and lower teeth in one area of the mouth. Each bite-wing shows a tooth from its crown to about the level of the supporting bone. Bite-wing X-rays are used to detect decay between teeth and changes in bone density caused by gum disease. They are also useful in determining the proper fit of a crown (or cast restoration) and the marginal integrity of fillings.
-
Periapical X-rays show the whole
tooth -- from the crown to beyond the end of the root to where the tooth is anchored in the jaw. Each periapical X-ray shows this full tooth dimension and includes all the teeth in one portion of either the upper or lower jaw. Periapical X-rays are used to detect any abnormalities of the root structure and surrounding bone structure. - Occlusal X-rays are larger and show full tooth development and placement. Each X-ray reveals the entire arch of teeth in either the upper or lower jaw.
Types of Extraoral X-Rays
There are several types of extraoral X-rays that your dentist may wish to take.
-
Panoramic X-rays show the entire mouth
area -- all the teeth in both the upper and lowerjaws -- on a single X-ray. This type of X-ray is useful for detecting the position of fully emerged as well as emerging teeth, can identify impacted teeth and aid in the diagnosis of tumors. -
Tomograms show a particular layer or "slice" of
the mouth while blurring out all other layers. This type of X-ray is useful for
examining structures that are difficult to clearly
see -- for instance, because other structures are in very close proximity to the structure to be viewed. - Cephalometric projections show the entire side of the head. This type of X-ray is useful for examining the teeth in relation to the jaw and profile of the individual. Orthodontists use this type of X-ray to develop their treatment plans.
- Sialography involves visualization of the salivary glands following the injection of a dye. The dye, called a radiopaque contrast agent, is injected into the salivary glands so that the organ can be seen on the X-ray film (the organ is a soft tissue that would not otherwise be seen with an X-ray). Dentists might order this type of test to look for salivary gland problems, such as blockages or Sjogren's syndrome.
- Computed tomography, otherwise known as CT scanning, shows the body's interior structures as a three-dimensional image. This type of X-ray, which is performed in a hospital rather than a dentist's office, is used to identify problems in the bones of the face, such as tumors or fractures.
In the Pipeline
There's a newer X-ray technique that your dentist already may be using or may soon be using. It's called digital imaging. Instead of developing X-ray film in a dark room, the X-rays are sent directly to a computer and can be viewed on screen, stored, or printed out. There are several nice benefits of using this new technology including:
- The technique uses less radiation than the typical X-ray and there is no
wait time for the X-rays to
develop -- the images are available on screen a few seconds after being taken. - The image taken, of a tooth for example, can be enhanced and enlarged many times it's actual size on the computer screen, making it easier for your dentist to show you where and what the problem is.
- If necessary, images can be electronically sent to another dentist or
specialist -- for instance, for a second opinion on a dental
problem -- to determine if a specialist is needed, or to a new dentist (if you move). - Software added to the computer can help dentists digitally compare current to previous images in a process called subtraction radiography. Using this technique, everything that is the same between two images is "subtracted out" from the image leaving a clear image of only the portion that is different. This helps dentists easily see the tiniest changes that may not have been noticed by the naked eye.
Reviewed by the doctors at The Cleveland Clinic Department of Dentistry.
Reviewed by Jay H. Rosoff, DDS, on March 1, 2007
Edited by Charlotte E. Grayson Mathis, MD, on May 1, 2005
Portions of this page © The Cleveland Clinic 2000-2005
SLIDESHOW
Oral Health: 19 Habits That Cause Bad Teeth See SlideshowHealth Solutions From Our Sponsors
Complete List
Top Dental X-Rays Related Articles
Abscessed Tooth
An abscessed tooth is an infection within a tooth that has spread to the root. Symptoms of an abscessed tooth may include pain, swelling, tenderness, redness, and the presence of a pus-filled lesion on the gum. A dental professional diagnoses an abscessed tooth and dental X-rays may be required. An abscessed tooth is treated with a root canal.
CT Scan (Computerized Tomography)
A CT scan is an X-ray procedure that combines many X-ray images with the aid of a computer to generate cross-sectional and three-dimensional images of internal organs and structures of the body. A CT scan is a low-risk procedure. Contrast material may be injected into a vein or the spinal fluid to enhance the scan.
Dental Crowns
Dental crowns are caps that encase the tooth with the purpose of restoring the size, shape, strength or appearance of the tooth. Crowns may be temporary or permanent and may be made out of materials such as porcelain, resin, or metal.
Dental Problems: Tooth Decay, TMJ, Mouth Pain Causes & Treatments
Do you have a toothache? What is oral cancer? Symptoms like mouth pain and sensitive teeth can indicate dental problems. Learn the causes of painful problems in your mouth like tooth decay, TMJ, and dry mouth. See how bad breath starts, and how to fight bad breath with dental treatments that work.
Dental Health Quiz
Take the Dental Health Quiz to test your IQ of oral hygiene, cavities, and common tongue and gum diseases. This quiz covers healthy mouths and teeth from brushing to flossing and everything in between check-ups!
Dental X-Rays: When to Get Them
Dental X-rays are used to identify tooth decay, bone loss from gum disease, reveal abscesses, and help with the preparation of dental implants, braces, and dentures. The frequency of getting dental X-rays depends on the patient's dental and medical history. Dental X-rays only expose the patient to small amounts of radiation.
Fillings
Dental fillings are used to treat cavities and teeth that have been cracked, broken, or worn down. Filling materials include cast gold, silver amalgams, composite fillings, ceramics, and glass ionomer. Amalgams containing mercury are considered safe. Regular dental cleanings, brushing, and flossing will help maintain fillings.
Gum Disease (Gingivitis)
Gum disease is caused by plaque and may result in tooth loss without proper treatment. Symptoms and signs of gum disease (gingivitis or periodontal disease) include receding gums, bad breath and pocket formation between the teeth and gums. Treatment depends upon the stage of the gum disease, how you responded to earlier treatments, and your overall health.
Pericoronitis
Pericoronitis is inflammation of the gum tissue around the molars. Pericoronitis commonly occurs in teens or young people when the wisdom teeth erupt. Symptoms include pain, swelling, swollen lymph nodes, and difficulty opening the mouth. Pericoronitis can be diagnosed by a dentist and is treated with pain medication. Severe cases may be treated with surgery.
Teeth Picture
The teeth are the hardest substances in the human body. See a picture of the Teeth and learn more about the health topic.
Temporomandibular Joint Syndrome (TMJ)
Temporomandibular joint (TMJ) syndrome is a disorder that causes symptoms like pain, clicking, and popping of the jaw. TMJ is caused by injury to the temporomandibular joint. Stress, poor posture, jaw trauma, genetic predisposition, and inflammatory disorders are risk factors for the condition. A variety of self-care measures (application of ice, use of over-the-counter pain medication, massage, relaxation techniques) and medical treatment options (dental splint, Botox, prescription medications, surgery) are available to manage TMJ. The prognosis of TMJ is good with proper treatment.
Toothache
A toothache is pain on or around a tooth. It may have a variety of causes, including a cavity, abscess, or even sinusitis. Toothache symptoms include pain, headache, earache, bad taste in the mouth, and gum swelling. Dental X-rays and other tests performed by a dentist are used to diagnose the cause of a toothache. Toothache treatment depends on the underlying cause. Taking proper care of the teeth and gums can help prevent toothache.
X-Rays
X-rays are a powerful form of electromagnetic radiation that has the ability to pass through solid objects. In medicine, X-rays are used to obtain an image of a part of the body. X-rays are necessary to diagnose many illnesses, for example, tumors, arthritis, dental problems, digestive or heart problems, and bone fractures. The side effects, dangers, and risks of having X-rays while pregnant or breastfeeding are provided.