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Tuesday
Apr172012

Are dental x-rays safe?

Recently, there have been several high profile reports about the dangers of dental x-rays.

Last year Doctor Oz reported that dental x-rays contribute to a rising incidence of thyroid cancer, and just last week a highly publicized study was published in the journal Cancer that reported a link between dental x-rays and meningioma, a common type of brain tumor.

So what is a patient to do?

I always encourage my patients to assess the risks vs. the benefits of treatments, and I believe in the vast majority of cases that the dangers of dental x-rays are negligible compared to their benefits.

First off, when you look carefully at the study reported in the journal Cancer, you see that the data is based upon patients’ self-reported frequency of dental x-rays rather than on their actual dental history.  My personal experience is that my patients remember far more frequent x-rays than they’ve actually had.  (I do this at the doctor’s office, too:  “Of course, I had my mammogram just a couple months ago”—when in actuality it’s been closer to two years.)  Plus, I think there is psychological tendency to search for easy explanations when we are struck with a disease or illness.  (Such as, “that slightly pink hamburger I ate last night must be the cause of my stomach upset”—even though no one else who ate the same meal was affected.) 

Also, radiation safety is vastly improved in the last 20-30 years, the time it theoretically takes for malignancies to develop following radiation exposure.  Modern dental offices use a number of means to reduce patient exposure, including:

  • lead shields
  • collimated tube heads
  • high speed films
  • intensifying screens
  • digital sensors
  • and annual registration and inspection of machines 

Modern dental x-rays create a tiny radiation exposure relative to even just living on earth.  Folks who live in Denver are exposed to twice as much cosmic radiation as those living at sea level, and a cross country airplane trip exposes a person to more ionizing radiation than a set of bitewing x-rays or a panoramic x-ray.  However, many routine medical x-rays create exposures hundreds of times greater than dental x-rays.  

That said, some new 3-D cone beam imaging systems being used by dentists today can provide much higher radiation doses than typical x-rays, depending on the machine used.   There are some valid concerns about the routine use of cone beam radiography in children in particular.  Personally, I do not find the need for cone beam studies in my orthodontic practice except in rare circumstances.

Moderation in all things.

There is growing evidence that mild challenges to our bodies’ systems are actually therapeutic.  We use tiny doses of tetanus, polio, diphtheria, etc., to stimulate our bodies’ immune systems to recognize and fight off larger challenges later in life.  The hygiene hypothesis asserts that we spend to much time indoors in homes that are too clean - we clean and filter and block out too much dust and pollen.  Therefore we and our children are more likely to develop environmental allergies, asthma, and a host of autoimmune and immunolgogical disorders.  I'm interested that several studies report that small amounts of chocolate, fats, alcohol, and many other seeming vices actually seem to be more healthful than none at all.

Interestingly, studies of folks who live at higher elevations vs. those who live near sea level, consistently show that those at higher elevations (and therefore receiving double the daily radiation exposure) not only live longer but also have lower incidences of cancer.  This is totally counter to the idea that all radiation is bad.  Could small doses, such as from dental x-rays, actually provide some degree of protection? 

That said, you might actually be justified in asking your dentist to extend the time between routine dental x-rays if:

  • you’ve never had a cavity
  • you don’t have any unerupted or impacted teeth
  • you brush and floss religiously (not many people really do, you know)
  • you have little or no plaque or tartar or bleeding gums
  • AND you get your teeth cleaned every six months,

But if you have any symptoms or evidence of disease, PLEASE do not hesitate to get the necessary x-rays your dentist needs to diagnose your problems.  You would never consider driving in the dark without your headlights, so don’t ask your dentist to treat you without x-rays!

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