Nov 142014
 

Short Answer: Maybe not

Long Answer: As dentists, one of our pet peeves is patients who refuse x-rays but then expect us to tell them why they have a painful tooth or if they have any other problems. Dentists are regularly challenged by patients who refuse x-rays because they don’t want to be exposed to them and they see little value in exchange for a higher risk of cancer. Some questionable dental advice forums even tell readers that a “skilled dentist” should be able to diagnose dental problems without x-rays at all. This is utter nonsense. The only way to detect cavities when they are small and between the teeth is with x-rays. A dentist who waits until a tooth hurts or a cavity is so large it can be seen without x-rays would be acting too late. By that point, far more expensive and complicated treatment would be necessary. Many of those treatments would require additional x-rays to complete and there would be an increased chance some of the affected teeth would be lost earlier in life. There is little disputing the enormous power of dental x-rays. As I tell my patients, upwards of 75% of my diagnosis comes from looking at them and only 25% comes from symptoms and a thorough clinical exam.

Fear of dental x-rays is a valid concern, for as everyone knows, x-rays can lead to cancer. But what most patients don’t realize is that the average dose needed for dental x-rays is very small compared to what they are envisioning. This is especially true when considering digital x-rays. Many are also not aware of how much radiation they are exposed to naturally 24 hours a day. There is radiation coming from outer space (cosmic radiation), from the ground and in the air we breathe. Radon gas, found at higher doses in some homes, is one of the leading causes of lung cancer, yet few people are very aware of it. Just a seven hour flight across the country exposes you to 0.03 mSv of radiation (Note: Dose of radiation is commonly measured in millisievert (mSv)). On average, when taking into account all this “natural” radiation, you and I are exposed to about 3.5 mSv per year.  If you went to the hospital and received a lower gastrointestinal tract x-ray, you would be exposed to a little over 4 mSv. By comparison, a set of four bitewing films in a dental office would expose you to 0.005 mSv, which is about HALF of a one-day-equivalent of “natural” background radiation. The amount is truly miniscule, so it’s important to keep things in perspective.

Nevertheless, we must not forget that all ionizing radiation is, indeed, harmful. Therefore, all x-rays should be kept to the bare minimum necessary. This is why I do object to cart blanc recommendations for annual or bi-annual x-rays when they are prescribed without regard for the patient’s specific situation. Unfortunately, most dentists pay no regard to the American Dental Association and Food and Drug Administration guidelines which recommend far fewer and less frequent x-rays than are usually prescribed. In their most recent guidelines, it was recommended to take four individual x-rays of back teeth (bitewing films) every two to three years, so long as the patient had no cavities and was not at an increased risk of developing them. For patients that have cavities and are susceptible to other dental problems, their recommendation is to take x-rays every six to eighteen months. Yet most dentists take updating x-rays on everyone every twelve months regardless of the circumstances. I believe this is largely a product of most dental insurance plans which pay for diagnostic x-rays once a year.

I have patients in my practice that are in their 30’s, they have never had a cavity, keep their mouth impeccably clean, use no medications and have no medical problems associated with increased dental problems (like diabetes or blood pressure medications). I believe it is unnecessary to prescribe annual x-rays for these patients, because the risk of radiation outweighs the extremely miniscule chance a dental problem will be discovered. The American Dental Association agrees with that perspective. For these patients I feel perfectly comfortable extending their x-ray frequency to every two or three years. Even average patients who have completed all their recommended dental treatment and have a track record of dental stability can easily extend their x-ray frequency to every 18 months. The patients I insist on seeing annual x-rays for are those with, among other things, previously diagnosed but untreated tooth decay, a history of recurring problems, many large/deep fillings, teeth that had root canals recently, changes in medications/medical situation, those with poor oral hygiene and those with active gum disease. When these patients insist on not having any x-rays, it puts me in a difficult situation. We as dentists are responsible for the patient’s oral health but want to honor their request. Some dentists have dealt with the problem by having affected patients sign a release form stating they don’t hold the dentist liable for not taking x-rays. This would likely not test well in court, because a medical provider cannot be released from practicing the Standard of Care (which is to take x-rays at least sometimes) by a patient. Nevertheless, the issue of x-rays remains a point of friction for many dentists and their patients.

As for children, my recommendation for frequency also falls in line with the American Dental Association recommendations. The frequency depends on whether or not the dentist can see between the teeth visually and whether the child has an increased risk or a history of cavities. In children, decay develops more quickly because baby teeth are softer and smaller than adult teeth. This makes it more important to catch cavities early.

WHAT TO DO

If a dentist recommends annual x-rays and you are concerned, ask what it is about your specific dental situation that leads to the recommendation. If the answer is something like, “Because it is our policy to take x-rays on everyone every year.”, then this would be a legitimate reason for further inquiry. If, on the other hand, the answer is, “Because you have several teeth we think have cavities, we’re not sure your gum disease is under control and we are still working out the kinks in your home care routine.”, this would be far more reasonable and well-thought-out on the part of the dentist.

It is important to remember that if indicated, refusing x-rays will increase your risk of enduring more expensive and potentially painful problems later on. Like most medical problems, early detection of dental disease is easiest to treat. While reducing exposure to x-rays is a legitimate concern, it should also be a concern that undiagnosed dental disease will affect your health and the health of your mouth. The key is to question whether your prescribed frequency is customized for your specific situation or not.

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  2 Responses to “Q: Do I really need all those x-rays every year?”

  1. Do you use rectangular collimation, as recommended by the ADA since 1989 to reduce radiation exposure? Disappointingly few dentists do.

    • Good question. Most dentists do not use a rectangular collimator (a device that is supposed to reduce the overall x-ray dose by confining the beam to only cover the rectangular x-ray film or sensor) because it increases their need for re-takes. That’s because it is very easy to crop out areas of interest if things are not placed 100% perfectly. There is no room for positioning error. If you have to do one retake, it was not worth the extremely small amount of radiation reduction you originally realized due to the collimator. Also, keep in mind that if the office is using digital x-rays, the total dose is about 80-90% less than when using conventional x-rays, so the overall dose is already very low to begin with. Typical digital x-ray radiation can be measured in terms of minutes out in the sun or sitting in an airplane at high altitude (things that expose you to radiation). It is a very, very small dose. As a patient, I would be more concerned with whether they are using digital or conventional x-rays well before I concerned myself with collimation.

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