April 11, 2012
You may have recently read news stories about dental x-rays being linked to benign brain tumors. We want to clarify a few points and assure you that every reasonable precaution is being taken to ensure your safety and minimize potential risks. For years, the recommendations concerning radiographic frequencies/techniques have been governed by a concept called ALARA (As Low As Reasonably Allowable). This means that you take x-rays at the lowest possible settings to obtain diagnostic radiographs, as well as taking them only when necessary. When are they necessary? According to the American Dental Association/FDA Guidelines there are many differences based on age, previous cavity experience and risk factors.
For new patients to our practice, baseline radiographs are necessary to determine current dental health and risks. If you have recent DIAGNOSTIC radiographs from your previous dentist, this may not be necessary. In this instance these x-rays are used to determine if there is decay between your teeth (which cannot usually be seen during a routine exam) and to check bone levels for signs of periodontal disease. Also radiographs are necessary to diagnose abscesses in patients having toothaches.
For recall patients with visible decay or increased risk of decay there are two different recommendations for children/teens and adults. In children and teens x-rays are indicated every 6-12 months. In adults this increases to every 6-18 months. This range means that it is on a case-by-case basis depending on risk factors.
For recall patients with no visible decay and not at an increased risk for decay there are three groups. For children the interval is 12-24 months. For teens the interval is 18-36 months and adults are 24-36 months.
The news story reported that most patients only needed x-rays every 3 years. As you can see, this frequency only applies to adults with little to no risk factors. According to Dr. Donald O’Rourke, an associate professor of neurosurgery at the University of Pennsylvania , it is also important to note that there is around a 20-25 year delay in radiation induced meningioma formation. The 1433 study participants mean age was 57, meaning that they were x-rayed using older technology. Digital radiographs have drastically cut radiation exposures. The study also relied on patient’s memories of whether they had received regular x-rays during the decades preceding the study, including during their childhood. Self-reporting of this frequency also leaves great room for error.
The amount of radiation that we are exposed to from dental X-rays is very small compared to our daily exposure from things like, cosmic radiation and naturally-occurring radioactive elements (for example, those producing radon).
The table below compares our estimated exposure to radiation from dental X-ray with other various sources. As indicated below, a millisievert (mSv) is a unit of measure that allows for some comparison between radiation sources that expose the entire body (such as natural background radiation) and those that only expose a portion of the body (such as X-rays).
|Source||Estimated Exposure (mSv)|
|Man MadeDental X-rays
|Medical X-raysLower gastrointestinal tract radiography
Upper gastrointestinal tract radiography
|NaturalCosmic (Outer Space) Radiation
Average radiation from outer space In Denver, CO (per year)
|Earth and Atmospheric RadiationAverage radiation in the U.S. from Natural sources (per year)||3.000|
Source: Adapted from Frederiksen NL. X-Rays: What is the Risk? Texas Dental Journal. 1995;112(2):68-72.
As always, please let us know of any concerns you may have so that together we can work to make a customized dental health plan that we can both agree on.
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