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Types of dental X-rays

Watch Graham Ramsden introduce the different types of dental x-ray sets.
Hello. My name is Graham Ramsden. I’m the technical manager for PHE’s Dental X-ray Protection Services. In this step, I’m going to take you through the different types of X-ray sets used in dental practices and point out the key features of each of them. The four main types of X-ray sets are intraoral, panoramic, cephalometric, and cone-beam CT. Almost all dental practices will have at least one type of X-ray set. The more specialist dental practices will most probably have a wider range available to them. The first X-ray set that I’m going to show you is an intraoral X-ray set, so-called because the imaging device, the film or the digital imaging system, is located inside the patient’s mouth for radiography.
There are more intraoral X-ray sets at dental practices than any other type of X-ray set. And general dental practices will probably have two or three of these on their premises. The equipment is used to image a few teeth on a single radiograph, with the two most commonly taken radiographs being the bitewing and the Periapical, sometimes abbreviated to PA. The bitewing radiograph shows an image of the crowns or the tops of a few of the upper and lower teeth on a single radiograph. Whereas the PA radiograph shows an image of the whole of one or two teeth to show the whole of the crown to beyond the end of the root.
Intraoral X-ray equipment is usually a fixed installation attached to a wall in a surgery. But there are also mobile units on a wheeled stand that can be moved between surgeries. Both versions have the head of the X-ray set fixed to the end of a long arm to allow it to be placed in the chosen position around the patient’s head. There are also handheld versions of intraoral X-ray sets, where the operator holds the X-ray set to take the radiograph. And these come in a pistol, or ray gun style, or the camera style. Approximately 1 in 20 dental practices has a panoramic X-ray set. There would not normally be more than one set on the premises.
Throughout this course, we will refer to them as panoramic X-ray sets. But other terms in general use are OPG or OPT, which are both shortened terms for Orthopantomograph. Panoramic radiography is a type of extraoral radiography, so-called because the imaging system is outside the mouth. To produce the image, the patient stands close to the X-ray set, and the X-ray head and imaging system rotates around the patient’s head. This imaging process produces a seemingly distorted image of the overall dentition of the patient. A basic full panoramic image shows the top and bottom jaws from left to right, and extends vertically from the bottom of the sinuses to just below the chin.
All panoramic equipment can also image the Tempromandibular Joint, shortened to TMJ. This is the hinge where the lower jaw locates into the skull, or upper jaw. This imaging produces four separate images on the same radiograph, corresponding to the left TMJ, open and closed mouth, and the same for the right TMJ. Cephalometric X-ray sets are generally used for imaging most of the patient’s head, and are used by orthodontists for treatments in the latter stages of skeletal development when braces are used in correcting and straightening the position of teeth. The name means “head measurement.” And through a course of treatment, a number of images might be taken to be able to monitor progress of the treatment.
The image that’s most commonly required is the lateral, or side view, of the patient’s head, and takes in the front section of the skull and the whole of the upper and lower jaws. The next most common image is the posterior-anterior, back-to-front, image. Cephalometric X-ray sets are now usually supplied as a combined panoramic and cephalometric unit, where the same X-ray tube is used for both types of imaging. And the equipment automatically sites the head of the X-ray sets in a position suitable for the chosen type of radiography. The three types of X-ray sets discussed up until now produce two-dimensional radiographs. Cone-beam computed tomography equipment can now be used to produce a three-dimensional reconstructed image of the teeth and bones.
I’m going to refer to the equipment as Cone-Beam CT, but it’s frequently shortened to CBCT. The main application for cone-beam CT in general dental practices is to aid the positioning of implants in a patient’s jaw so as not to damage facial nerves. However, the equipment may also be used for the radiography of impacted maxillary canines in children. Cone-beam CT equipment has the appearance of a panoramic X-ray set. And like a panoramic X-ray set, the X-ray head and imaging system rotate around the patient’s head.
Graham Ramsden introduces the main types of dental X-ray sets.

The video covers the 4 most common X-ray sets found in dental practices: Intraoral, Panoramic, Cephalometric and Cone Beam Computed Tomography. Key features of each set are highlighted including what images can be taken, the applications for each set and how sets are installed in practices.

Which of these X-ray sets do you most commonly use in your practice? Let us know your experience in the comments below.

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Dental Radiography: Radiation Protection in Dental Practice

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