Many patients today ask about the type and number of X-ray images recommended in dental practices. Even though the exposure from a single dose is minimal, patients are concerned about the cumulative effects of minute amounts of radiation over time. These concerns have been the focus of media shows such as Dr. Oz and the dental community.
A study published in Acta Oncologica Journal in May 2010 found an association between self-reported multiple dental X-ray exposures and the risk of thyroid cancer. Although this method of gathering information may be questionable, the results of this study should not be disregarded. In a column in the Journal of the American Dental Association (ADA), a dentist raised the question of the ethical obligations of using dental X-rays.
The consensus is that dentists should order X-rays based on the patient’s condition and risk of disease development or progression. For example, according to the ADA and the US Department of Health and Human Services guidelines, having many dental restorations is one factor contributing to a higher risk of cavities and the recommendation is to have check-up X-rays at 6-18 month intervals.
In a recent presentation, Dr. Anthony Pogrel, Professor and Chairman of the Oral and Maxillofacial Surgery Department at UCSF, compared the absorbed radiation of dental X-rays to other natural sources. Each individual is exposed to 3,000 Microsievert annually by just living in the U.S. While a typical cross country airplane flight exposes travelers to 20 µSv, a digital dental panoramic X-ray exposes patients to only 5 µSv. According to the U.S. Nuclear Regulatory Commission, a yearly dose of 6200 µSv from all radiation sources has not been shown to cause humans any harm.
To minimize dental radiation exposure, it is recommended to use protective lead aprons and thyroid collars whenever possible. Both can be used during Bite-wing X-rays while checking for cavities. However, the thyroid collar cannot be used during a Panoramic X-ray while evaluating wisdom teeth. Another way to reduce exposure is to use digital X-rays where exposure can be up to 50-80% less than traditional film X-rays.
Without X-rays, dentists are unable to detect diseases at early stages before they demonstrate clinical signs or symptoms such as cavities that start between the teeth, and thus unable to provide minimally invasive treatment or monitor disease progression. Concerned patients should evaluate what is in their best interest when they consider their total radiation exposure.
— Samer Alassaad is in private dental practice in Davis. Contact him at [email protected]