In recent months we have seen a lot of news reports on the need for dental x-rays and the possible long term effects of radiation on patients. One report that aired on all the major networks and caused a lot of hype was greatly flawed because it relied on anecdotal evidence rather than patient charts or dental history. That said, what are dental x-rays? How many kinds are there? Why are they needed and how often? And how much radiation are we really exposed to? Dental x-rays are pictures of the teeth, bones and surrounding soft tissues to screen for and help identify problems with the teeth, mouth and jaw. X-Rays can show cavities, cancerous or benign masses, hidden dental structures such as wisdom teeth and bone loss that cannot be seen during a visual examination. Dental x-rays may also be taken as follow up after dental treatment.

THERE ARE 3 TYPES OF DENTAL X-RAYS:
The initial full mouth series: taken at the initial visit and every 3-5 years subsequently. Consists of 4 bitewing films which are taken at an angle specifically to look for decay and 14 periapical films which are taken from other angles to show the tips of the roots and the supporting bone. The yearly bitewing series: consists of either two or four films taken of the back teeth (although some offices may take them of the front as well). The patient bites down so they can get an image of both upper and lower teeth. It is the minimum set that most offices would take to document the internal structure of teeth and gums.

The Panoramic x-ray film: is the only one that is extraoral, meaning it is taken from the outside of the mouth. It is a large single film that shows the entire bony structure of the teeth and face. It shows the sinuses and temperomandibular joints, as well as other pathological structures such as: cysts and position of wisdom teeth (third molars). In addition to medical uses they are good for forensic (legal) purposes in the identification of otherwise unrecognizable bodies.

These images can be captured in traditional film or digitally. In traditional film a film is placed in the mouth and then must be developed with chemicals in a dark room. This process exposes the patient to higher radiation and if developed incorrectly can result in additional exposure if the image must be retaken. Digital x-rays are relatively new. Traditional film is replaced with a flat electronic pad or sensor. Instead of developing in a dark room, the image is sent to the computer where the image appears on screen. Digital x-rays reduce radiation exposure by as much as 80%.

What does this mean in terms of our exposure and how does it compare to other forms of radiation we are exposed to every day? According to Frederiksen, NL. X-Rays: What is the Risk? Texas Dental Journal, 1995; 112 (2): 68-72, when walking around, the average person is exposed to 360 mRem per year.

Dental radiographs exposure is as follows:
4 bitewings, traditional film—3.8 mRem
4 bitewings, digital—1.3 mRem
Full Mouth Series, traditional film—18 mRem
Full Mouth Series, digital—6 mRem
Panoramic, traditional—1.9 mRem
Panoramic, digital—.63 mRem

At Dr. Mary Gharagozloo’s dental office we use digital radiography and stay on top of the latest news and studies to ensure your safety and well being when treating your dental health. Please call us or refer to our website for any information you may have on the subject.