Answer to Question #468 Submitted to "Ask the Experts"

It is extremely unlikely that you have suffered any adverse effects or placed yourself or your (potential) unborn child at any additional risk from your occupational exposure to dental x rays. Available data indicate that typical occupational exposures to dental personnel average about 0.7 mSv per year. This can be compared with average environmental (background) exposure of about 3 mSv per year. (Environmental exposure is from naturally occurring sources and applies to everyone in the United States.) The National Council on Radiation Protection and Measurements recommends an occupational exposure limit of 50 mSv in any one year, with maximum accumulated dose at the rate of 10 mSv per year. They also recommend a limit of 0.5 mSv per month for pregnant females during their pregnancy. These limits are set below known threshold doses for acute radiation effects, including congenital anomalies from exposure in utero. The limits are also below doses that lead to significant increase in delayed radiation effects, such as cancer or mutation. Your occupational exposure may or may not be in the typical range of 0.7 mSv per year. Because of your pregnancy you should observe all available methods of minimizing your exposure. If possible you should position yourself with a structural barrier between you and the x-ray beam during exposure. An ordinary wall will be helpful. If this is not possible, position yourself as far as possible from the beam and away from the primary beam as it exits the patient. You may wish to discuss with your employer the possibility of obtaining a radiation monitor that will provide a monthly readout of your occupational exposure. These monitors are inexpensive and can provide great peace of mind. I urge you not to panic. Although no one can state with authority that the risk to your unborn child is zero, there are no data to prove otherwise.

S. Julian Gibbs, DDS, PhD