Yearly dental X-rays raise brain tumor risk, study finds

(CBS News) Many patients who visit the dentist each year get an X-ray. A new study says yearly common dental X-rays may raise a person's risk for developing meningioma, the most common type of brain tumor found in Americans.

"This research suggests that although dental X-rays are an important tool in maintaining good oral health, efforts to moderate exposure to this form of imaging may be of benefit to some patients," study author Dr. Elizabeth Claus. a neurosurgeon at Brigham and Women's Hospital in Boston and Yale University School of Medicine at New Haven, said in a hospital written statement.

More preschoolers showing up to dentists with 10 cavities or more, says report
Women in their 40s more likely to have dental anxiety and phobia, study says
9 common medical procedures you may not need

For the study, Claus and her colleagues studied more than 1,400 patients between the ages of 20 and 79 who had been diagnosed with the meningioma, and compared them to a group of 1,350 healthy controls between the same ages. Compared with control subjects, patients with a brain tumor were twice as likely to say they had a specific type of dental X-ray called a "bitewing exam." A bitewing X-ray shows details of the upper and lower teeth to detect decay between teeth and bone density changes caused by gum disease, according to WebMD.

Overall, patients who reported having yearly bitewing exams were up to two times more likely to develop meningioma. Patients who reported having another type of dental X-ray called a panorex -  which provides a panoramic broad view of the teeth, sinuses and jaw - were almost five times more likely to develop a meningioma, compared to controls. Those who got that exam yearly had an overall risk three times greater to develop the tumor.

Since the study questioned participants on past X-rays, "It is important to note that the dental X-rays performed today use a much lower dose of radiation than in the past," Claus said.

The study was published in the April 10 issue of the American Cancer Society's journal, Cancer.

Should everyone eschew dental X-rays out of tumor fears?

Dr. David Langer, director of cerebrovascular research at North Shore University Hospital in N.Y., told CBS This Morning, "Yes and no."

For folks experiencing severe tooth pain or other dental symptoms, an X-ray's benefits may outweigh the risks, he said. If a person is not having symptoms, he doesn't think the X-rays are necessary.

"I don't think dentists want to give their patients tumor," Langer said. "Just question it - it never hurts to question, 'Do we really need to do this today? Is it absolutely necessary?'"

According to Claus, patients should be more aware about current American Dental Association guidelines for X-rays. The ADA says healthy children should get one X-ray every 1-2 years, teens should receive one every 1.5-3 years, and adults should get a scan every 2-3 years if they aren't experiencing dental problems.

"Widespread dissemination of this information allows for increased dialogue between patients and their health care providers," she said.

Questioning conventional medical wisdom has made recent headlines for other types of doctors. A new campaign from nine leading medical societies called "Choosing Wisely" tells patients to question 45 common medical tests that may be unnecessary, and could lead to to more harm than good.

The American Dental Association, however, has criticized the study for relying on patients' memory of which X-rays they've gotten over the years to reach its results

"Studies have shown that the ability to recall information is often imperfect," the ADA said in a  statement. "Therefore, the results of studies that use this design can be unreliable." The ADA maintains it's "long-standing position" is that dentists should order dental X-rays for patients only when it's necessary for diagnosis and treatment, it said.

Meningiomas account for 33 percent of all brain tumors diagnosed in the U.S.. Most are benign, or noncancerous, but Langer warns a meningioma depending on its location in the brain can be detrimental. Symptoms include changes in vision, headaches that worsen over time, hearing or memory loss, seizures and weakness in extremities.

The American Dental Association has more on dental X-rays.

[mikehanley]

This is a textbook case of classic recall bias, where a study group with cancer, for example, remembers being exposed to something that the study is trying to link more so than a group without cancer. Even the authors and the American Cancer Society admit this flaw, but yet it is throughout our news and forever linked in many people's mind. The radiation dose from 4 bitewings is 0.005 mSv which is less than one day of natural background radiation (0.008 mSv). It would be equally valid to propose that people born in a leap year have increased cancer risk (not true, by the way). For more info visit www.xrayrisk.com.

[Noplak]

Shame on you guys for irresponsible reporting! With all the data that was the one thing they had in common???? they all remember having a bitewing x-ray???? Gee I bet they all worn blue jeans too! Get a grip!what about the other millions of people who had those scarey bitewings and did NOT develop the brain tumor? just lucky I guess. What will we scare the public with next?

[DStern2478]

I was shocked to hear Dr. Langer's comments that one should only get a dental x-ray is they are having symptoms or pain. Unfortunately, by the time someone has symptoms or pain, tooth decay has entered the inner most area of the tooth, called the pulp. Bacteria enter the pulp through the tooth decay and cause infection and inflammation. When this happens, treatment becomes more complicated, less predictable, and more expensive, requiring root canal therapy and then restoring the tooth with a crown, or extracting the tooth.Dental x-rays are taken to discover tooth decay before symptoms happen. X-rays show us decay entering the tooth from in between the teeth, the part of the tooth that we cannot see by visual inspection.

The question then becomes, how often should we take x-rays. There is no set answer that holds true for everyone. The dentist must first assess the patient oral condition and take into consideration multiple factors when making the decision.

Usually, dentists will want a recent full mouth x-ray series to assess the health of the teeth, examining the bone levels around the teeth, determining the presense and extent of tooth decay, and assessing if there are any hidden abscesses or any other undignosed
pathologies hidden in the jaws, such as tumors, cysts and impacted teeth. If the patient has gum disease (periodontal disease), a full mouth x-ray has more definition to assess bone levels. If the patient has no periodontal disease, a panoramic x-ray and bite-wing x-rays are usually sufficient.

When seeing a patient for the first time, a dentist must assess several things: when did the patient last see a dentist and did the patient have a recent full mouth series, panoramic x-ray and bite-wings taken at the patient's previous dentist. A dentist will want a complete series of x-rays to establish a baseline for the patient. It is always best for dentist to have a copy of a new patient's previous x-rays, if they are available. If these x-rays are current and no additional problems are found, they are often times adequate and then the dentist does not have to take additional x-rays.

For patients of record, how often x-rays are taken are based upon the individual condition of the patient's mouth. These factors include:
1. The age of the patient
2. Whether the patient currently has active decay in thier mouth.
3. When the patient last had active decay.
4. Whether there are small areas of decay that are being watched to see if they have gotten bigger.
5. Whether the patient is wearing braces.
6. Whether the patient has exposed root surfaces between the teeth.
7. An assessment of the patient's diet, to include soda intake and suger ingestion.
8. Whether the person has a history of having a high level of the bacteria that cause tooth decay.
9. An assessment of the patient's oral hygiene.
10. Whether the patient's family has poor dental health.
11. Whether the patient has any developmental or acquired enamel defects.
12. Whether the patient has a history of many multisurface restorations.
13 Whether the patient is on any medications or undergoing chemo/radiation therapy.
14. Whether the patient has any eating disorders.
15. Whether the patient has a history of alcohol or drug abuse.
16. Whether the patient has a history of irregular dental care.
17. Whether the patient has a history of periodontal disease.
18. Whether the patient has a number of restorations that don't adapt well to the teeth.
19. Whether the patient has physical or mental disabilities.
20. Whether the patient has impacted teeth.

After assessing these factors, the dentist will determine if the patient has a low, medium or high risk for dental disease. How often x-rays are taken are based upon the patient's risk assessment.

Generally, for those who have a low risk factor for dental disease, bite-wing x-rays should be taken every 2 years, and a full mouth x-ray should be taken if there is a sudden change in a patient's oral condition.

For those people with moderate risk factors, bite-wings should be taken every 1-1.5 years and a full mouth x-ray every 3-5 years, unless there is a sudden change in the patient's oral condition, which may require a new full mouth x-ray series to assess the problem.

For those with high risk factors, bite-wing x-rays may need to be taken every 6 months to 1 year and a full mouth x-ray may need to be taken every 3 years.

I feel that it is important that your show continue reporting on this so that the public can be educated about this in a more non-emotional and rational manner. I would also recommend that you take care to get more input from various sources before discussing an emotionally charged issue such as cancer.

Michael S. Stern, DMD, ****
International Editor
Alpha Omega Dental Fraterity
14955 Shady Grove Road, Suite 200
Rockville, MD 20850
301-610-9909
[e-mail]

[bastardsonofelvis]

This is irresponsible science and journalism, and the ignorance of the reactionary public never ceases to amaze me. This is why amalgam restorations, which last easily three times longer than their composite counterparts, were taken out of our arsenal despite the fact that you ingest more bioavailable mercury in one piece of fish than from a mouthful of them over your lifetime.

As to some idiot claiming that your dentist takes radiographs purely to generate fees -- we use them as a tool to diagnose carious lesions when they are small and inexpensively treatable. By the time your tooth hurts or has a hole in it, that ship has sailed. Root canals and crowns are way more expensive than radiographs and fillings. And composite restorations fail and require replacement much more often than amalgam. And the health concerns are unsubstantiated. The public hurts itself when it makes decisions about things it does not understand. I am a dentist and my family and myself will continue to have radiographs taken at the recommended intervals. You decline them at your own peril.

[dentalgirl8]

This is a VERY poor study and I can't believe it actually got published. "Compared with control subjects, patients with a brain tumor were twice as likely to say they had a specific type of dental X-ray called a "bitewing" exam." Key phrase ... twice as likely to say! Did they actually remember how many they have had? let's be real!

Another article on this subject states that dental xrays are the most common artificial source of ionizing radiation in this country. It takes almost 70 full mouth series (an fmx is around 18 films) to equal the amount of radiation you would receive in 1 chest film if you were to go to the hospital. That's 1,260 dental exposures to 1 chest exposure!!!!

[Orthogirl]

The relationship is far more complicaed than the 9 words title says. I see major flaws with this study. Is it possible that these unfortunate study subjects are under such stress that they are "searching" for something to blame (why would a study ask about dental xrays unless someone suspects a correlation?)? Could these people be more "health conscious" than most people and they were more likely to seek dental and, eventually, medical care? They were asked to "REMEMBER" when they had xrays and the type of xray!!! Some of these people were in their 70s. Most of my patients (I am a dentist) cannot remember what they had for lunch yesterday. How can they remember with accuracy something that was done decades ago. This makes the study unreliable!

Someone should do a study to find the correlation between "going to the doctor" and a "diagnosis of a problem". MAYBE going to the doctor makes you sick... haha.
Were there other factors that were corrleated with the meningioma? Other ionizing radiation exposures, work/ home environment, genetics?
Shame on the media for using scare tactics to oversimplify a very complicated problem with a poorly explained study.

[longtree-2009]

remember when the dds started pushing xrays every year. refused and was told it was recommended by ADA. no doubt, to make money. sure if you have poor teeth, tons of dental problems, it might be needed but not every 6 months nor every year. chest xrays, brain scans are routinely done at hospitals more as a legal requirement, theirs, to protect themselves from lawsuits. a brain scan can cause a tumor in about 40 years but it's not proven science, the 40 years from a doctor re a relative who needed a brain scan to rule out abnormalities.

[SeattleMark952]

In the last few years, I've asked my Dentist/Assistants to forgo the mid-year Xray and get a patronizing treatment (like I'm a paranoid patient). It does takes some guts and personal analysis to realize that the Doctors may not be not be right about everything (and stand up for yourself).

[RichZubaty]

I have been complaining about this for years. I am sick to death of the over-testing and over-xrays in American medicine. It's all about money. For profit health care sucks.

[healthymama]

This is absurd. It is poor science. They didn't mention that digital xrays have less radiation than previous films. And guess what? step outside for 30 seconds to go to your car and you got more radiation than 1 digital xray.

[Lerianis4]

Yes, they did. While they have 'less radiation', NO radiation directed at your head is the gold standard.

[erasmus111]

"And guess what? step outside for 30 seconds to go to your car and you got more radiation than 1 digital xray."

And so the point is to eliminate all the exposure you can, because it all adds up!