Dental X-Rays–How Safe?
Everyone, of course, has an interest in limiting the amount of radiation they are exposed to, and since teeth xrays are frequently used in dentistry, the question naturally arises as to how harmful these might be. The answer is that rigorous scientific investigation indicates the amount of radiation absorbed per dental x-ray is trivial, as described here.
- Radiation is present everywhere – the universe is awash in it. Every object is mildly radioactive, radioactivity reaches the Earth from space after being generated by the sun, and even radon gas coming out of the ground can add to the local radiation levels.
- All living creatures, including humans, have evolved to be healthy and unharmed below a certain radiation threshold. The key to remaining in good health is to ensure that critical threshold is not crossed.
- Radiation is measured in microsieverts, or μSv. Human tolerances for radiation are quite well established by decades of research and real-world observation.
- The rate of radiation absorbed per year by a typical American citizen from the natural environment is approximately 3,000 μSv, according to Environmental Protection Agency figures.
- Living in a brick house exposes a person to around 100 μSv annually due to radiation in the materials used. Use of a propane stove for cooking meals likewise generates around 100 μSv of exposure per year. Flying on a jet airliner exposes you to 5 μSv per hour, since the atmospheric absorption of radiation from space is less at that altitude.
- Sleeping in the same bed as another person exposes each individual to 20 μSv of radiation yearly, while reading books a few hours every evening can produce 10 μSv of radiation exposure over the course of 365 days.
With these figures in mind, it quickly becomes clear that dental xrays deliver a very low dosage of dental radiation. Looking at the microsievert situation in terms of bitewings, which are x-ray images frequently taken for oral health assessment and dental services, the lowest dose is probably a two-bitewing scan for children. This delivers 8 μSv. The adult equivalent doubles the number of bitewings and thus the dose, or a total of 16 μSv. The most complex dental x-rays are likely to generate a maximum of 88 μSv, but x-rays this detailed are seldom used. The maximum dosage for individuals participating in studies that involve x-rays or other radioactive exposures, as determined by the American government, is 50,000 μSv per year. This is equivalent to 3,125 adult bitewing x-ray sets over an annual period, or 8.6 x-rays daily, day in, day out, without any holidays. The maximum recommended exposure for children is ten times less, or 5,000 μSv, but this still equals 624 juvenile bitewing sets, an impossibly high number. Clearly, a few dental x-rays are going to have basically zero impact on human health; it is impossible by the laws of physics unless thousands of x-rays are taken annually.
Advancing Technology Means Less Radiation
The advance of the digital age has brought fresh, exciting changes to the medical world, and made many things possible which would have been impossible just a decade or two ago. The dental radiation safety figures listed above are those using the old style x-ray, which utilized film and therefore needed high enough doses of x-rays to make an actual chemical change in the film. Using digital radiography, a sensor that is far more sensitive than film is placed in the mouth to pick up the x-rays as they pass through the teeth. Due to the high sensitivity of this method, only 1/20th as much radiation needs to be used in order to produce an image – and, in fact, that image is superior to any that film could offer. Our office has used digital radiography since June 2000, and we are thoroughly experienced in its use and in making high quality diagnoses from the results. Among the beneficial effects that this technique offers to you, as our patient, are the following:
- Greatly reduced exposure to radiation, which was very low to begin with.
- Use of thyroid collars to protect the delicate thyroid gland
- Digital x-rays are stored on a computer or other electronic storage device, making it impossible to lose them and greatly increasing their portability.
- Digital radiographs enable better diagnosis.
- Dr. Gibbs is thoroughly versed in the use of digital dental x-rays, and can use the computer to boost contrast to enhance detail greatly, magnify the image, and otherwise make the most of the available data for an extremely accurate diagnosis.
How Much Radiation are in Dental X-Rays (Compared to Nature and other Common Medical X-Rays )
Procedure Radiation Dose Compared to Natural Environm
Naturally occurring environmental radiation, (measured in milliseverts) is 1.26 per year
One Small Dental X-ray 0.005 Millisieverts less than one day
Cone Beam CT Scan 0.06 7 days
Chest X-ray 0.1 12 days
Mammogram 0.4 7 weeks
CT of spine 6.0 2 years
CT colonoscopy 10.0 3 years
CT angiography (heart) 12.0 7 years
PET with CT 25.0 8 years
These figures are from a 2015 article in Consumers Reports and considered current and reputable. Individual x-rays machine will vary and figures are considered to an average.