Dental X rays a significant cancer cause

Radiation safety of dental X-rays questioned, by ALEX ROSLIN on AUG 14, 2013“………..In a study in the journal Cancer last year, 1,433 people with men­ingioma were found to be two times more likely to have had a “bitewing” dental X-ray as those without the illness. Those who reported having a panorex scanning dental X-ray (which gives a two-dimensional panoramic view of the mouth) before age 10 were 4.9 times more likely to have meningioma.

Meningioma is the most common form of primary brain tumour (tumours that start in the brain). Women get it more than twice as often as men.

Other studies have linked dental X-rays to thyroid cancer, breast cancer (in women who hadn’t worn a shielded apron), saliva-gland tumours, and glioma (a cancerous type of brain and spinal tumour).

Pregnant women who got a dental X-ray were three times more likely to deliver a low-birth-weight baby (weighing less than 2.5 kilograms), according to a 2004 study in the Journal of the American Medical Association.

Dental X-rays are the most common way Americans are exposed to human-made radiation, the 2012 Cancer study said.

Yet despite growing awareness about the risks of X-rays, radiation in many dental offices is actually rising. That’s thanks to the explosive growth of 3-D cone-beam CT (computed tomography) machines, which give off up to 60 times the radiation of a conventional dental X-ray.

CT manufacturers heavily market their machines to dentists, promising unsurpassed detail about a patient’s mouth. The marketing includes payments to prominent dentists to give talks to colleagues, ads in dental magazines and displays at dental conferences, according to a 2010 New York Times investigation.

“Kids love to see that 3-D image,” one orthodontist said in a webcast sponsored by a CT maker.

The marketing often minimizes the radiation exposure from the machines, while experts on dental radiation criticize the growing “indiscriminate use” of CT scans for routine screening, particularly by orthodontists, the story said.

“The parents of these children have no idea about the amount of radiation used in these CT scans, and even more frightening, neither do the dentists,” Nicholas Dello Russo, an instructor in periodontology at Harvard University’s school of dental medicine, told the Times.

Here in B.C., the first CT machine was introduced in a dental office in 2006 or 2007. Today, five to 10 percent of dental offices use one, according to Daniel Hanson of Langley-based Innovative Biomedical Engineering.

Hanson’s company is hired by the B.C. Dental Association to inspect dentists’ X-ray machines to ensure they comply with radiation safety regulations. That doesn’t include looking at patients’ radiation-exposure records, which Hanson said no one in the province is tracking…….

The increasing use of dental CT scans is part of a trend of patients being exposed to increasing amounts of other medical X-ray radiation. In the U.S., radiation exposure from diagnostic medical X-rays has shot up more than sevenfold for the average person since the early 1980s, in large part because of the use of medical CT machines, according to a 2009 study by the U.S.-based National Council on Radiation Protection & Measurements.

An estimated 29,000 cancers (half of them fatal) will result from the 72 million medical CT scans done in 2007 alone, the U.S. National Cancer Institute said in a different 2009 study.

Yet only nine percent of emergency-room doctors believe CT scans increase cancer risk, and only three percent of patients think so, according to a 2004 study in the journal Radiology.

Growing awareness of risks from dental X-rays prompted the U.S. Food and Drug Administration (FDA) in 2009 to call on dentists to reduce radiation by switching to faster-speed types of X-ray film that require less radiation……


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