Blog Archives

Dental X-Rays

It never fails, I hear it all the time, “I don’t want x-rays, I just want a cleaning” and “Dr. OZ says dental x-rays cause thyroid cancer.” Comments such as these are commonplace in the field of dentistry.  However, no matter how many times I explain the value of dental x-rays coupled with the ultra low dose of radiation, many patients remain skeptical.  So, in an attempt to clear the air, I will try to break it down into understandable terms.

We live in a radioactive world and radiation is part of our natural environment.  Simply put, we are all exposed to radiation on a daily basis.  This radiation (specifically, ionizing radiation) can be measured in several different ways, but for the purpose of this discussion I will focus on the smaller unit called millirem (mrem).

The average exposure dose of radiation per person from all sources is about 360 mrems per year. However, it is not uncommon for someone to receive more or less than this average in a given year (largely due to medical procedures one may undergo such as CT scans).  For those who work with and around radioactive material, International Standards allow exposure to as much as 5,000 mrems per year and still consider this dose as “safe”.

The following are common sources of radiation EVERYONE receives:

  • Cosmic (from outer space) Radiation at sea level = 28 mrem/year  (more if you live in an area with higher elevation like Denver, CO)
  • Terrestrial (from the ground) Radiation = 30 mrem/year
  • From Food and Water = 40 mrem/year
  • From Air = 228 mrem/year

Dental X-rays (Radiographs)

  • Full mouth series (need at first visit and every 5 years) = 54 mrem
  • 4 Bitewings (need every 1 or 2 years) = 12 mrem

Other Man-made Sources of Radiation for Comparison

  • From living with another person = 1 mrem/year
  • From living in a stone, brick or concrete building = 7 mrem/year
  • Flying from LA to NY = 2.5 mrem 
  • Smoking a half pack of cigarettes every day = 18 mrem/year
  • Mammogram = 42 mrem
  • Hip x-ray = 70 mrem
  • CT scan of chest = 700 mrem
  • CT scan of heart = 2000 mrem

Ionizing radiation in large doses can cause damage to the human body. However, the very small and localized amount used in dentistry far outweigh the risks.  Dental x-rays diagnose a wide range of problems, including but not limited to: dental caries (cavities) that cannot be seen clinically (by looking in the mouth), periodontal disease (bone loss), excess cement left behind after cementing a crown (which can lead to gum disease), abscesses /cysts, infections in the bone, impacted teeth, fractured teeth, cancer, genetic disorders, and much more.

Finding a dental problem early can save your tooth. It will also save you time, money, and overall health.
So the next time you go to your dentist and he/she says it’s time for x-rays, feel free to ask why. Any good dentist will take the time to explain why x-rays are indicated.

American Nuclear Society:
Martin S. Spiller, D.M.D:
Idaho State University:
United States Nuclear Regulatory commission: