Folks naturally have concerns about the X-rays that we take in dentistry, and what is our radiation exposure as patients. Here are some points to consider about the safety of dental radiographs, especially our modern digital ones:
First, the X-ray beams are collimated (directed, contained) by lead in the tubes on our machines.
Then we always have our patients put on those lead aprons which protect our bodies so well that even sensitive equipment cannot measure any radiation getting through the lead. They're heavy, but effective! Actually some patients ask for the lead apron when we treat them, even when no X-rays are required. It seems that there's a comfort value, something akin to crawling under your covers and escaping the world at large...
With our modern digital radiography the exposure is lessened compared to analog films. Then, with a Panoramic film, there's a phosphor plate next to the film that acts as an amplifier, further reducing the exposure.
We also have to do risk assessment in a totally rational way, without preconceived notions-
Ever fly across country or overseas? Besides those questionable scanners that the TSA is starting to force on travelers in airports, flying delivers a significant whole-body radiation exposure due to the simple fact that modern jet airliners fly in the stratosphere, well above the protective effects of most of the Earth's atmosphere:
This radiation exposure is a whole lot worse than dental radiographs because of many factors, but the main one is that it's whole-body. Ugh!
Plus, we take our films at long intervals, a Panoramic or full set every 5 years, bitewings every year. The diagnostic value is intense- in fact we aren't legally allowed to treat people without them being taken at some reasonable interval, because working without that critical diagnostic information would be so far below the standard of care.
"Risk assessment" is actually always difficult, because we all have so many biases. We have to train ourselves to look at things clearly. For instance:
I, for one, ride my bike to work (9 miles, more when I meander home) once a week or so in the nicer weather and yet will not go near a roller coaster, sushi or any automobile or house from which I can hear Mariah Carey on the sound system. And what happens? Last year I got hit by a car while cycling. (Actually the police report clearly states that I hit the car, which was embarassing and not favorable from an insurance standpoint. But it WAS raining!)
I therefore engage in a fairly risky behavior and shun others that are statistically far safer, simply because I feel that I have control over the situation. And look what happens!
Dental X-rays help us to diagnose periodontal (gum) disease, endodontic (root canal) infections, and hidden cavities that we cannot easily see even with our vision augmented by magnifiers. All of these conditions are best treated as early as possible. The danger to our health is minimized, and in the case of oral infections this is a real threat. New studies show over and over again that the bacteria themselves and the inflammation that they result in are an important causative factor in heart disease and stroke. Cavities, when they get deep, lead to infections in the mouth, mostly through the root canal systems of our teeth. Yes, early treatment is better in every way. Even from a cost standpoint- early treatment is less expensive treatment.
So, when looking at the issue through the lens of risk assessment, doses of diagnostic X-rays that are kept to the minimum that technology allows and that provide valuable information about our health are acceptable and are worth the exposure.
Let's look at just a few examples of serious diagnoses made possible by X-rays.
Here is a "silent" root canal infection- there's no pain at all, yet the large dark halo around the root of the middle tooth in the film is our first sign of infection:
We evaluate these "radiographic findings" and confirm our suspicions by examining our patients directly- I'm always mindful of my professors' admonitions to "treat people, not X-rays", but these films are an essential piece of the diagnostic puzzle. These kinds of infections have many potential effects on our overall health as well, especially on our cardiovascular system.
Periodontal or gum disease is usually one of those conditions without painful symptoms; other examples are high blood pressure and glaucoma. Until the later stages when something bad happens, there's no pain. One of our patients once famously said, "Give me novocaine, I'm philosophically opposed to pain", which I thought was a beautiful way to phrase it, but still the presence of pain is one of our body's most effective warning signs. When it's absent we can get into major trouble and not even know it. This X-ray shows angular bone loss of the middle tooth in the film. That V-shaped contour is not good, not good at all:
Periodontal disease is even more of a cardiovascular threat than are root canal infections.
Perhaps the most common diagnosis we make with X-rays is that of cavities between the teeth. This X-ray actually shows a special case; I use it as an example because it's easy to see the random dark shape inder the filling (lighter) on the third tooth from the left:
We might feel that cavity with an instrument if the soft area of tooth was large enough, but we'd never see it- it's under the gums. Plus, the whole point is that we want to catch these things before they get to any significant size.
Speaking of size, this is an artist's conception view from a hypothetical planet circling around the double star Beta Lyrae- a truly magnificent source of X-rays and many other kinds of radiation. From a safe distance, it must be astonishingly beautiful...