A panoramic radiograph is a type of dental x-ray sometimes used to generate an image all of the teeth at once. Unlike other dental x-rays, it is not suitable for detecting cavities, but provides a general image of the teeth, jaw, and some soft tissues. Panoramic radiographs are a type of tomography because images are created and blurred together from a mobile radiation source. The space that is imaged by the machine is known as a focal trough, which is where the teeth, bone, and other features can be seen. Patients usually need to be positioned so that the images appear clear and anatomical structures such as the hard palate don’t obscure the picture.
In addition to covering a large area in a short amount of time, a panoramic radiograph uses a low dose of radiation. It can also be used on patients that aren’t as mobile as required by other x-ray machines. Children, the handicapped, and patients that can’t keep their mouths open can be imaged as well as most other people. The system is often used to view impacted teeth before a dental procedure or fractured facial bones, jaw growth, and tumors and cysts.
On the panoramic radiograph, a film that is between 5 and 6 inches (about 12.7 to 15.2 centimeters) wide is typically used. The wider the film, the more of the jaw included in the image. Wider films are more suitable for imaging the hinged joint of the jaw. The resulting pictures are usually clearer in the middle of the focal trough and somewhat blurry toward the edges. This is caused by the overall motion of the machine while the image is taken.
Patients typically receive specific instructions while a panoramic radiograph is taken. They are usually told to position the tongue as if swallowing, sit up straight, and remove jewelry or dental implants. If the position isn’t correct, sometimes anatomical or other structures can make it look there is a bone fracture. Dental specialists should also know the placement of bones, blood vessels, and nerves so that these aren’t mistaken for problems of the jaw or teeth.
Panoramic radiograph machines often come in many choices of products. Each machine can operate differently, so the specialists and technicians working with it should study the instructions from the system’s manufacturer. On some machines, the focal trough can be adjusted for each patient. The measurement can also be displayed as a number on a digital screen. This enables dentists to use the same number for the patient in future scans, so the machine can automatically adjust to the patient’s physique.