By: Elaine Gottlieb for Dental1A trip to the dentist may be a little less costly and hazardous to your health, thanks to a new study which found that one type of x-ray - the panoramic - may not be needed for routine dental care.
Types of x-rays
When the dental assistant places the heavy x-ray shield over your body, you probably don’t think about what type of x-ray will be taken. It could be one of three types of x-rays - periapical, bitewing and panoramic - which serve different purposes.
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Dental X-Rays at a Glance
"Bitewing": an x-ray used to identify tooth decay
"Periapical": used to reveal root structure, bone levels, cysts and abscesses
"Panoramic": sometimes used for routine diagnostics also to view jaw abnormalities or to get a full picture of the mouth before surgery
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Like a wide-angle photograph, the panoramic x-ray provides a wide view of the teeth, jaws and surrounding structures and tissues in a single comprehensive image. While some dentists recommend taking panoramic x-rays every few years, they are used primarily to investigate jaw abnormalities and get a complete picture of the mouth before oral surgery. The average cost for these radiographs is $74. Periapical radiographs reveal root structure, bone levels, cysts and abscesses while the bitewing identifies tooth decay. What the study showed
Researchers at the University of Buffalo of Dental Medicine wanted to find out whether the panoramic x-ray is useful as a routine diagnostic tool. They evaluated 1,000 randomly selected panoramic x-rays of 536 women and 464 men who had been seen at the dental school’s clinic. Of the 352 lesions that were found, only a few would not have been detected on periapical x-rays. In those cases, the lesions were located in the sinus cavities of the cheeks, soft tissue of the neck and upper portion of the jaw bone.
“You can’t assess cavities or gum disease on a panoramic x-ray. If a small x-ray isn’t good enough for a condition you see in a patient, then a panoramic x-ray can be done. But our results show it isn’t necessary routinely for every single patient,” said Lida Radfar, senior author of the study and an assistant professor of oral diagnostic sciences in the University of Buffalo School of Medicine.
Dr. Robert Chapman, chairperson of the Department of Prosthodontics and Operative Dentistry at Tufts University School of Dental Medicine in Boston, concurs with the study results. “It shows that the information you get from periapical radiographs are sufficient for most needs. If you don’t get that much information from the panoramic x-ray, why use it except for specific purposes.”
Dental x-rays and radiation
The biggest concern with dental x-rays, as with all x-rays, is radiation exposure. “Any radiation causes damage to cells; over time it has a cumulative effect. All practitioners try to keep the risk down,” said Chapman. Radiation is more prevalent than most people realize; its sources include outer space, minerals in the soil, and home appliances, such as smoke detectors and television screens. The radiation from dental radiographs is less than other common medical tests. For example, a full-mouth series generates .038 millisieverts (the unit of measure for radiation) as compared to 4.060 for a lower GI series. “You get as much radiation exposure from a high-altitude flight as you do from typical dental x-rays,” Chapman said.
In the not-so-distant future, dental x-rays will use the same technology as CT scans and provide a more comprehensive view with less radiation exposure, according to Chapman.
Talk to your dentist
If you are concerned about radiation exposure, check with your dentist about the type of x-rays being taken and why they are needed. “Asking questions is always a good idea,” confirmed Chapman. “It gives you more information to make sound decisions about your dental care.”
