Common Types of X-rays
There are many types of x-rays that can be taken by dental professionals. The type of x-ray needed depends greatly on the treatment the patient needs to undergo. Here are some of the most common types of x-rays.
Apical radiographs: provide a detailed view of the entire mouth, from the crown down to the bone that helps support the tooth.
Bite wing films: provide details of the upper and lower rows of back side teeth. This type of x-ray also allows the dentist to see how these teeth are in contact with each other.
Panoramic films: show details of the teeth, jaw, nose, sinuses and jaw joints and are usually taken when the patient is likely to need orthodontic treatment.
Occlusal films: provide a clear and detailed view of the jaw and help identify any extra teeth or teeth that have not yet grown past the gum line.
In addition to traditional dental x-rays, there are also panoramic x-rays, which create separate images of the entire mouth: the upper or lower jaw, the TMJ, the entire set of teeth, the nasal area and the sinuses. This type of photograph flatly reflects the curved structure of the jaw and allows for easier analysis of each area.
Why use panoramic x-rays?
Because panoramic radiographs can show the entire mouth in one picture, without the need to generate detailed pictures showing the cavity of caries. These radiographs can show bone abnormalities and fractures, cysts, blocked teeth, infections and tumors, among other problems. Dentists who suspect any of these problems may consider taking panoramic x-rays of their patients.
How are these radiographs taken?
Unlike traditional intraoral x-rays, dental panoramic x-rays are taken outside the mouth, meaning that the imager and film are outside the mouth. According to the Radiological Society of North America (RSNA), a dental panoramic x-ray machine projects light through the patient's mouth onto a film or detector that is rotated to face the x-ray tube.
The basic design of a dental panoramic radiograph is that the tube is mounted on a horizontal bar that can be pointed toward the side of the patient's cheek, while an opposing horizontal bar points toward the side containing the radiographic film or detector. Typically, the head is positioned through the lower handle, forehead and sides, and the mouth is kept open with a set of swallowing stops. The rod of the x-ray machine then rotates in a semicircle around the patient's head, starting on one side of the lower handle and ending on the other.
Panoramic X-rays allow the dentist to get a comprehensive view of the patient's entire mouth in a single picture and take a relatively short time. However, according to the Society of Pediatric Radiology, a single panoramic x-ray has a radiation exposure of 0.02 microsieverts, four times the 0.005 microsieverts produced by four bitewing x-rays for a regular exam.
