Radiographs, commonly know as x-rays, are an essential tool for your CDA member dentist to properly diagnose your oral health. They allow your dentist to see beyond what can be seen visually and provide the ability to diagnose dental disease in the early stages– before it has advanced to the point of causing discomfort and destruction. X-rays assist the dentist in determining the presence and degree of dental caries (cavities), periodontal disease, abscesses and abnormal growths, such as tumors or cysts. They also show the location and condition of impacted or unerupted teeth.
The type of x-rays taken and the interval between x-rays is dependent upon the condition of your mouth, the degree of active disease present and what oral structures your dentist needs to see.
- One of the most common sets of x-rays is known as “bitewing” x-rays. A bitewing set is usually four x-rays that are placed by your back teeth. You may recognize them as bitewings because you “bite” on a cardboard tab to hold them in place. Bitewing x-rays show the crowns of your molar and premolar teeth, and the height of the bone between your teeth, aiding in the diagnosis of cavities and periodontal disease. Bitewing x-rays are usually recommended at one year intervals. Your dentist may recommend taking them more or less frequently than this, based on your oral health.
- Another set of x-rays that is commonly recommended is the “full-set,” so named because it shows all areas of your mouth. A full-set of x-rays, usually comprised of 14-20 individual films, is generally recommended during one of the first visits with a new dentist to aid in proper diagnosis and treatment planning. A full set shows all of your teeth and all of the surrounding bone, aiding in the diagnosis of cavities, cysts or tumors, abscesses, impacted teeth, and periodontal disease. Full-set x-rays are usually recommended at 3-5 year intervals.
- Still another x-ray that you may be familiar with is called a Panorex. This is a full-mouth x-ray that is taken without ever putting an x-ray film into your mouth. Instead, as you sit still, the x-ray head rotates around you, providing one solid film of your jaws and teeth. This type of x-ray is particularly helpful for seeing the entire upper and lower jaws in one shot and can image impacted teeth or other hidden structures that could be difficult to see completely on the small, individual film used for a “traditional” full-set.
- You may also hear your dentist use the term “periapical (PA).” This type of film refers to a single film that is usually used to see a specific area of concern. If you come in with a toothache, your dentist is likely to recommend a “PA” film to see that tooth in its entirety.
It's important to remember that without x-rays, your dentist is limited in his or her ability to see the beginning of a problem. The types and frequency of the x-rays your dentist recommends is based on his or her responsibility to do a complete exam and to ensure that problems are detected early, when destruction of your teeth or gums is lowest and repair is the least costly.
Due to very fast film that reduces exposure time, and lead lined x-ray equipment to prevent radiation scatter, radiation exposure associated with dental x-rays is extremely low. A bitewing set consisting of 4 x-rays is just a small fraction of the amount of radiation that a person is exposed to from natural background radiation over one year (4 microSv versus 3600 microSv). Additionally, compared with a hip x-ray at 1700 microSv, for example, it is clear that dental x-ray exposure is very low. Still, in an effort to keep radiation exposure to anabsolute minimum, a lead shield should be placed over your body when x-rays aretaken. A thyroid collar that shields your neck, while not mandatory, is also generally recommended.
Remember, x-rays are an important diagnostic tool for your dentist. He or she should recommend only the x-rays needed to ensure your optimum oral health. If you have concerns about the types or frequency of the x-rays your dentist recommends, ask questions. Early detection and treatment of disease is the best way to ensure you keep your teeth for a lifetime.