Panoramic radiographs (x-rays) are used in dentistry to image the entire upper and lower jaws all at once.
What are panoramic radiographs used for?
Panoramic x-rays are useful in dentistry for the follow reasons:
- To see wisdom teeth. Wisdom teeth are difficult to capture on the x-ray films or sensors that are inserted into the mouth. It usually causes gagging. The panoramic film, however, provides an excellent view of all the wisdom teeth and no gagging.
- To look for infections. Dentists routinely take bitewing x-rays to look for cavities. Bitewings are the ones where the film or sensor is placed in your mouth and you bite. Only the crowns of the back teeth are imaged—not the roots. Sometimes there’s an infection at the end of a root, but no pain or swelling. In this case, the individual would not know there’s an infection. The panoramic x-ray would reveal an infection missing by the bitewing image.
- To look for abnormalities such as cysts or cancer. Some cancers involve bone and can show up as a dark spot on the image. Cysts and other similar lesions that involve bone can also show up on panoramic films. These abnormalities most often cannot be seen with bitewing films.
- To see the jaw joints. These can be seen quite well on panoramic images. The dentist looks for changes in the shape of the condyle (the ball part of the ball and socket joint just forward of your ear canal). A change in shape may be due to osteoarthritis, rheumatoid arthritis or TMD (temporomandibular dysfunction—most people call it TMJ).
- To see if the roots are straight. When doing braces (Orthodontics), the dentist needs to see if the roots of teeth are parallel to each other or not. Sometimes a tooth root is tipped the wrong way if the bracket was placed a little incorrectly. The crown of the tooth might look normal. So, during treatment the dentist or orthodontist will take a panoramic x-ray to see all the roots and how the line up. If something’s a little off, a change in the bracket can be made.
- To look to gum disease. Periodontal disease is when there’s loss of bone around teeth due to an infection of the gums. This bone loss can be seen on the panoramic film.
What are the Advantages?
There are several advantages to panoramic radiographs. They include:
- Broad coverage of facial bone and teeth
- Low patient radiation dose
- Convenience of examination for the patient (films need not be placed inside the mouth)
- Ability to be used in patients who cannot open the mouth or when the opening is restricted e.g.: due to trismus
- Short time required for making the image
- Patient’s ready understandably of panoramic films, making them a useful visual aid in patient education and case presentation.
- Easy to store compared to the large set of intra oral x-rays which are typically used.
How Does It Work?
The person stands in the machine, rest their chin on a chin rest, and bites on a plastic stick. On one side of the head there’s the x-ray source. On the other there’s the capture sensor. While imaging is taking place, the source and sensor rotate around the person’s head resulting in an image of the jaws that is spread out in plane.