I am going to talk about different types of dental Xray images taken and their applications. They can be broadly categorized as intraoral images and extraoral images. Intraoral images are Xray images taken inside patient’s mouth and they includes periapical radiograph, bitewing radiograph, Full Mouth Series radiograph, and occlusal radiograph. The extraoral images are Xray images taken outside patients mouth and they include panoramic radiograph, cephalometric radiograph, and the 3D Cone-Beam Computed Tomography radiograph.
Periapical radiograph is the Xray image captured the entirety of teeth, and it is especially useful for seeing the bone structure around each individual tooth. It is useful for detecting the root canal infection because if there is an infection, there is a darken area enveloping the tip of the root of the tooth.
Bitewing radiograph is the Xray image capturing the parallel view of teeth. The bitewing radiograph is captured at the approximately 90 degree angle to the horizontal axis of the tooth. A proper bitewing radiograph should clearly show the edge of each tooth and there should not be any overlapping of the two adjacent teeth in the image. Because of the angulation, the edge of the tooth is the clearest and this allows for detection of tooth cavity at the contact area of the tooth with the adjacent tooth. Bitewing radiograph is especially useful for clinician to diagnose any dental cavity in between two teeth because this area cannot be seen visually and only this type of radiograph allows clinican to “see” the dental cavity.
The Full Mouth Series radiograph is a complete set of radiograph for every teeth in a person’s mouth. Typically it consist of 18 images in total, in combination of anterior periapical radiographs, posterior periapical radiographs and bitewing radiogaphs. Usually dentist would take this FMX radiograph at the time of comprehensive examination for new patient. And also dentist would update the FMX radiograph at every 3-4 years interval.
Panoramic radiograph is taken with the panoramic machine, in which the images are created by xray tube and sensors extraorally. During the image capture, the xray tube and sensor will rotate around the patient’s head. The xray tube will emit the xray and the sensor will record the xray. As the sensor is rotated, different area of the oral cavity is reconstructed onto a 2D image. This is good for showing the sinus, jaw bone, and overall dental condition of the patient. Also, it is useful for oral surgeon to determine the location of the wisdom tooth in relation to the jaw bone, sinuses, the nerve canal and the adjacent tooth.
Cephalometric radiograph is the side view of a patient’s head area. It shows the bone morphology, the position of teeth, and skeletal structure. It is commonly used by the orthodontist for planning of orthodontic treatment.
3D cone-beam computed tomograph is the 3D reconstructed view of head and neck area. It is taken at a machine similar to the panoramic machine. The Xray tube and sensor are also located extraorally and they too rotate around the patient’s head during image capture. The major difference is that the resulting image is the 3D rendition of the patient’s face, showing the skeletal bone structure and the teeth.
Written by Daniel Tee, DDS, MS
Practicing General Dentist Serving the city of Tempe, Chandler, Phoenix, Gilbert, and Mesa in Arizona.