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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.

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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.

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