Good dental health should include regular visits to the dentist. In addition to a thorough examination of the mouth and teeth during these appointments, the dentist will sometimes order x-rays. A dental x-ray is the common term for a dental radiograph. It is one of the dentist’s most important diagnostic tools, giving him or her a better picture of what’s going on with your teeth than simply looking in your mouth.
Dental radiographs work by using a small, controlled burst of radiation to create a picture of the tooth. Cavities, infections, and other conditions show up as dark spots on the lighter image of the tooth.
Different types of x-rays have different purposes, depending on what the dentist is trying to see. There are four common types of dental x-rays, each used for different purposes
Bite-wing x-rays are the type that most people are familiar with. They get their name from a tab on the x-ray film. The patient bites down on the tab so the image will show both top and bottom teeth.
Dentists use bite-wings to get a picture of the back (posterior) teeth. They are not typically done on front (anterior) teeth. The images will show the biting surface and the area where the main part of the tooth meets the root. They can also show what’s underneath existing fillings.
The main use of a bite-wing x-ray is to see if there is tooth decay. They may also be used to see how the teeth touch each other when the patient bites down.
Periapical x-rays can be are used on both posterior and anterior teeth. They allow the dentist to focus in on one specific tooth. The image shows the entire tooth from the biting surface all the way up to the tip of the root, as well as the surrounding bone.
When a patient is complaining about tooth pain, dentists may use a periapical x-ray to see exactly what the problem is. These x-rays may be used to determine if a root canal is necessary. Endodontists use them to monitor the progress of endodontic treatments.
Occlusal x-rays take a picture of either the floor of the mouth or the palate, commonly known as the roof of the mouth. They show the entire skeletal anatomy of the area including the full set of teeth and the jaw.
The piece of film used to take the x-ray is about three times bigger than bite-wing and periapical, which are about one square inch in size. The film is placed in the mouth between the top and bottom teeth. The x-ray machine takes the image from beneath the chin for a view of the lower teeth and jaw, or from above near the nose for the upper teeth and jaw.
Occlusal x-rays are most commonly used by pediatric dentists to check on the growth and formation of the teeth and jaw bone. They can detect teeth that have not grown in yet and how they are developing. In adults, the images can show impacted teeth, issues with the jaw, or masses such as tumors.
Panoramic x-rays are like panoramic photos. They show the entire mouth instead of just a “snapshot” of a few teeth. Unlike other dental x-rays, these images are taken from outside the mouth instead of inside.
The patient stays still while an x-ray machine moves in an arc from one side of their head all the way around to the other. The result is one long image that shows all of the teeth and jaws, but also the nasal cavity and sinuses.
When a patient is getting braces, panoramic x-rays give an orthodontist the best view of the mouth. They are also used to help with the placement of dental implants or to detect wisdom teeth for removal.
Are Dental X-Rays Safe?
The fact that dental x-rays involve exposure to radiation concerns some people. In reality, the amount of radiation used for a traditional x-ray is very small, especially when compared to the amount humans are exposed to in day-to-day life. The American Dental Association (ADA) and the U.S. Food and Drug Administration (FDA) have determined that they are safe for everyone, including children and pregnant women.
Radiation can, however, accumulate in the body over time. Dentists recognized the importance of limiting the number of x-rays so that build-up is kept to a minimum. Unless there is a good diagnostic reason, most dentists will only order x-rays once every 12 or 24 months. If a patient has a medical condition requiring numerous x-rays, the dentist may choose to forgo dental x-rays for that individual unless absolutely necessary.
Following Safety Guidelines
While there is little danger from all types of dental x-rays, the ADA and the FDA have collaborated to put guidelines in place to limit the risks even more for both patients and dental technicians. State and local health agencies may have their own guidelines as well.
Dental offices and their x-ray equipment are subject to state and local inspections and licensing. They adhere to certain procedures when doing x-rays. For example, lead aprons or capes are placed on the patient’s body to avoid exposure. Also, at one time, patients would hold the x-ray film in place themselves. Today, holders are used for this purpose. And technicians will step out of the room when x-rays are used to limit their own exposure.
As technology has advanced, every type of dental x-ray has become even safer. Conventional x-rays use photographic film that is developed using chemicals in a dark room, much like photos are. Over time, improvements have been made to the film that used in the process, so that patients are exposed to radiation for a shorter time.
Also, many dental offices are now using digital images instead of film. Not only is time saved in the development process, reducing the amount of radiation by as much as 80%.
3D Imaging Using CBCT
An offshoot of dental X-rays is 3D imaging. Orthodontists and dentists use Cone Beam Computerized Tomography (CBCT), which evolved from CAT (Computerized Axial Tomography) Scan technology. More commonly known as Cone Beam Imaging, it creates a panoramic 3D image of a patient’s entire dental anatomy.
The scan time for a CBCT machine is very short, keeping a patient’s radiation exposure to a minimum.The technology provides images that are more accurate and detailed than a 2D image. It gives a much more comprehensive view that shows the teeth, jaw, joints, and how they all fit and move together in the skull.
X-Rays: The Best Diagnostic Tool
The benefits of getting an x-ray far outweigh the risks. With these types of dental x-rays, dentists have the ability to literally see what’s going on inside their patient’s teeth. They are able to diagnose issues like cavities early and fix them quickly, helping patients avoid unnecessary pain, cost, and further damage.
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