We are often asked by our patients about the safety of dental x-rays. Many people are concerned about the radiation they are exposed to when diagnostic x-rays are taken. Since exact measurements are difficult to obtain, this article will use averages and comparisons to help you understand the radiation dose you receive from dental x-rays.
Understanding Dose from X-rays
A set of four bitewing x-rays, which is typically taken once per year, delivers an average effective dose of 0.005 milliSievert (mSv). Effective dose is not measured. Effective dose is calculated by taking the dose delivered to the specific organs exposed during an x-ray and accounting for the sensitivity of the tissues exposed. Those values are then summed over all of the tissues in the human body to calculate an effective dose, which allows us to compare doses delivered in different ways to one another.
Comparing the dose from a set of four bite-wings to other doses we are exposed to daily is a useful way to understand dental x-ray doses in context. In the graphic below, dental bitewing x-ray dose is shown in comparison to other medical exposures and different sources of naturally occurring background radiation. Naturally occurring background radiation is exposure that each of us gets every day, and some of us more than others depending on the location in the world in which we live. In the chart below, the average US doses are shown. The total US average natural background dose from all sources per year is right around 3 mSv, or 600 times greater than the dose from one set of four dental bitewing x-rays, so you would nearly need to have bitewing x-rays twice a day for a year to equal the dose you receive annually just from living on the planet.
Risk from Dental Exposures
What most people worry about when they hear the word “radiation” is whether or not it can cause cancer. The likelihood of an adverse effect (cancer) given an exposure to radioactivity is also known as risk. The delivery of radiation dose to the head and neck area during a dental x-ray does come with some associated risk. According to the World Health Organization (WHO)’s publication, Communicating radiation risks in paediatric imaging: Information to support healthcare discussions about benefit and risk, the increased risk of cancer incidence from various types of diagnostic x-rays can be compared with baseline lifetime cancer risk. This publication focused on risk to children because: “children are more vulnerable than adults to the development of certain cancer types, and have longer lifespans to develop long-term radiation-induced health effects.” Basically, kids are more susceptible than adults to cancer from radiation because they will live longer from time at exposure than their adult counterparts and their bodies are still growing and developing, so their organs are more vulnerable to exposure. WHO’s studies showed that the increase in cancer incidence, or risk, for children aged 1-10 years from dental x-rays is <1 in 500,000. That risk would be even lower in an adult. Levels of risk are generally considered to be “acceptable” among agencies that regulate radiation exposures to the public if they are in the range of 1 in 10,000 to 1 in 1,000,000. The cancer incidence risk from dental x-rays to children reported by WHO falls directly in this range of acceptable risk.
The benefit of dental bitewing x-rays is the early detection of multiple types of oral disease, including cavities, gum and bone infections, and oral cancer. As with any disease, the earlier it is detected, the less invasive treatment can be and the better the long-term prognosis. The risk of these diseases going undetected is the progression of disease, spread of infection, loss of teeth, loss of bone in the jaws, and in severe cases even death.
Risk vs. Benefit
Due to the prevalence of oral diseases and the risks associated with those diseases, it is the opinion of our practice, as well as that of the American Dental Association, that the benefits of early detection with diagnostic x-ray imaging far outweigh the risks associated with the x-rays. The risk of adverse consequences from undetected dental and oral diseases is significantly greater than the risk of increased cancer incidence due to dental x-rays. Because each patient has different risk factors, the number of x-rays and the frequency at which they are taken can vary widely and is always determined on a case-by-case basis with the utmost respect for balancing patient concerns with positive outcomes. For example, a patient with a higher risk for cavities or periodontal disease would benefit from more frequent dental x-rays than a patient who has a very low risk for either cavities or periodontal disease. The more aggressive a dental condition is, the more frequently dental x-rays are needed to provide the best preventive and interceptive dental care.
X-rays and Pregnancy
The American College of Obstetricians and Gynecologists Committee on Health Care for Underserved Women reaffirmed its committee opinion in 2015: “Patients often need reassurance that prevention, diagnosis, and treatment of oral conditions, including dental X-rays (with shielding of the abdomen and thyroid) … [is] safe during pregnancy.” Dr. Jason, Dr. Alex and Dr. Serena typically postpone any dental x-rays during a patient’s pregnancy until after the baby is born unless the patient has a very high risk for disease, which could affect the patient’s overall health and that of the pregnancy.
Concerned about Radiation from Dental X-rays?
The number and type of dental x-rays taken on every patient is customized for his or her specific needs. Call our office at 605-925-4999 (Freeman) or (605) 928-3363 (Parkston) to schedule your appointment today with Dr. Jason Aanenson, Dr. Alex Whitesell or Dr. Serena Whitesell!