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Procedures

Radiographs

Procedure overview

Learn about the dental procedure, when it is generally prescribed, and other information which can increase your knowledge of the topic.

Alternate terms: X-rays.

Radiographs, ("X-rays") are used by dental health professionals to evaluate hard tissue (teeth and bones) for signs of disease process or abnormalities.

The type of radiograph prescribed is determined by the type of information the dentist is seeking:

Bitewing Radiographs

Bitewing radiographs (X-rays) may be exposed to evaluate your hard tissues (tooth and bone) for tooth decay, bone loss, or signs of other disease processes. Bitewings allow a look at teeth in both jaws with a single film. They normally don't show any tooth in its entirety unless they are positioned in the mouth vertically. Vertical bitewings are most commonly used in patients who have a history of periodontal disease. A series of bitewing radiographs is necessary to visualize all of the teeth.

Bitewing X-rays in younger children may often be excluded if there is enough space between their molar teeth to see and brush between them; and if there is no visual sign of decay when the dentist examines them. As the six-year molars begin to move toward eruption into the mouth, they often push the primary molars forward and close the spaces between them. At that point, bitewing X-rays may be advisable to evaluate the surfaces which can no longer be seen visually.

Bitewing X-ray showing dental implants and natural teeth with crowns

Figure 1: Bitewing radiograph showing several dental implants (upper) which have been restored with crowns, biting against natural teeth, also restored with crowns.

Intraoral cameras are effective communication tools to show radiographic tooth decay

Figure 2: This photographic sequence shows a cavity (see arrow) that could not be seen clinically before removing the overlying tooth structure. It was diagnosed using a bitewing radiograph. The lower left frame shows the cavity has been enlarged to remove the decay. The lower right frame shows the cavity restored with a tooth-colored filling.

Periapical Radiographs

Periapical radiographs show one to several teeth (or implants) in their entirety. They are one of the most frequently prescribed diagnostic images used in dentistry for an assessment of the teeth and bones.

Periapical X-ray shows dental implant with crown and endodontically treated tooth

Figure 3: Periapical radiograph showing the patient's upper front teeth, one of which has been replaced with a dental implant.

Panoramic Radiographs

Panoramic radiographs show the bones of the head and neck, as well as the teeth as they might be visualized by walking in a circular pathway around your head. The image is then projected onto a flat plane. It shows all of the teeth and any disease process of hard tissue in the head and neck that are in the field of view. Panoramic radiographs can also be used to screen for stroke risk, as calcification of the carotid arteries can sometimes be observed in these images, depending on the field of visualization. A partially obstructed carotid artery is evident in Figure 4 (see arrow).

Panoramic dental X-ray can show calcified carotid artery identifying stroke risk (CVA)

Figure 4: Panoramic radiograph, lightened using software, to better show the partially calcified right carotid artery (see arrow).

Cephalometric Radiographs

Orthodontic tracings on a lateral cephalometric X-ray (radiograph)

Figure 5: Cephalometric radiographs show the bones of the head and neck from the side, as well as the teeth. They are frequently used by orthodontists to assess growth and development. They can also show fractures and evidence of disease processes. (Image courtesy Thomas J. Melcher, DDS, MS).

Cone Beam Scan Radiographs

Cone beam scans are "volume" X-rays that show depth, length and width. It is an emerging technology for use where more diagnostic information is needed than other types of dental radiographs can produce. The images are not distorted and can be used to measure true length.

Cone beam scan X-ray images are a type of volumetric computed tomography

Figure 6: Cone beam scan radiograph showing twelve cross-sectional images of the patent's upper jaw.

Full Mouth Series

A series of approximately twelve to twenty individual intraoral radiographs (X-ray images), which are used to assess the teeth and tooth-supporting (alveolar) bone in such a way that the teeth are visible in their entirety. The various angles of exposure allow the dentist to evaluate between the teeth for decay, and to check for signs of infection or other disease processes in the bone surrounding the tooth roots. The number of exposures required depends on the number of teeth the patient has; however, the cost of an adult full mouth series is not typically the same as the usual four-film X-ray series (two bitewing and two occlusal X-ray images) needed to image a child's mouth.

Occlusal Radiographs

Occlusal radiographs are used to evaluate the anterior (front) teeth of children for tooth decay, signs of infection, and presence / relative position of the permanent incisor and canine teeth.

Gemination (a type of twinning defect) of primary incisor

Figure 7: Here, an occlusal radiograph was exposed to determine whether the tooth with two clinical crowns (known as a twinning defect—see arrow) represented a "gemination" (which it was) or a "fusion"—as well as to assess the permanent teeth developing beneath the tooth (which were normal).