7 replies to this topic

[rwac]

NEW YORK (Reuters Health) - A new study suggests people who had certain kinds of dental X-rays in the past may be at an increased risk for meningioma, the most commonly diagnosed brain tumor in the U.S.

The findings cannot prove that radiation from the imaging caused the tumors, and the results are based on people who were likely exposed to higher levels of radiation during dental X-rays than most are today.
...
For her study, Claus' team recruited 1,433 people diagnosed with intracranial meningioma -- a tumor that forms in the tissues lining the brain -- between May 2006 and April 2011. All of the participants were diagnosed when they were between 20 and 79 years old and they were all from Connecticut, Massachusetts, North Carolina or the Houston or San Francisco Bay areas.
...
The researchers found that those diagnosed with meningiomas were more than twice as likely as the comparison group to report ever having had bitewing images taken.

Oops, forgot link: http://www.ibtimes.c...brain-tumor.htm

Edited by rwac, 10 April 2012 - 04:55 PM.

[Mind]

One supposed flaw in this study is that it is based on self-reporting (memory) of having bitewing images taken. However, I don't think this would introduce significant error since it is not a difficult thing to remember, except for perhaps the oldest in the study, who might suffer from some mental decline.

I had these x-rays a few times when I was younger. I couldn't say how many....5...maybe up to 10 times. Since I was quite inquisitive even while I was younger, I always asked what the dentists were seeing in the x-rays. They would say "look at this cavity here". To tell you the truth, I never saw anything that looked out of the ordinary, but I did have some tooth pain from time to time which seemed to be taken care of by drilling and amalgam. Interesting story: a work colleague of mine went to a dentist office, got the x-rays, the dentist said she had like 4 or 5 cavities and they needed to be drilled and filled. She didn't see anything in the x-rays (like me when I was younger), so she went to a different office and they said she didn't have any cavities. They cleaned her teeth, normal check-up, and she was fine.

The last time my wife got x-rays she asked them if the x-rays were safe. They said yes. She asked "if they are safe, why do you make me wear a lead vest?" They couldn't offer a coherent answer.

[Spherical Cow]

Dentistry is a messy medical industry. Of all the healthcare fields, I would wager that dental appointments cause can cause more problems than people are aware of. If dental x-rays increase the risk of a type of brain tumor, then what for the risk of oral cancer? or thyroid cancer? http://www.medicalne...cles/191025.php or http://jnci.oxfordjo...80/12/943.short

Interestingly though, this study finds a decreased risk for gliomas.

Just walking into a dental operating room is hazardous enough...

Edited by Spherical Cow, 11 June 2013 - 08:38 PM.

[Adamzski]

Are bitewings different to other x-rays? how? different to a modern opg where the xray machine circles your head?

I do remember having a few xrays when I was younger that the dentist described as a bite wing.

[niner]

Bitewings are extremely common. We've probably all had them. I wouldn't get too excited about this problem, however. This research is pretty flaky. They took a bunch of people with cancer and asked "if they could remember" having bitewings, and I suppose to estimate the number of them. That's pretty weak data. The people will obviously have made a connection between x-radiation and cancer, unless they've been living in a cave for the past half century. This will predispose them to "remember" better.

[Spherical Cow]

Yeah its relatively weak, retrospective, and observational. The X-ray-cancer connection is key. We might expect x-rays of the oral cavity to possibly increase this risk of oral and head cancers.

But who is surprised by this possible oral X-ray-head cancer link?

However, for the accurate imaging and assessment of tooth decay and periodontal disease what other methods are currently available to dentists? A mini MRI scan of the oral cavity?

A good dentist will explain the risks and let the patient decide whether they are comfortable with procedure. A bad dentist makes the decision for the patient.

[StephCThomp]

Note that this study observes a link but does not claim causation.

 

Here's a perspective to help balance things out:  Incidence of Intracranial Meningioma is 0.008%, comprising mostly women.  Of these cases, over 90% are benign.  So incidence of malignant IM is less than 0.0008% = less than 1 person per 100,000 population.  This means: Don't worry about it.

 

Secondly, when studies are working with stats so fractional it's hard to interpret anything meaningful from them, least of all causation from a questionable correlation.  The overwhelming likelihood is that any true differences in rates of IM will be because those who require more x-rays are less healthy, in their genetics or health habits, than those who require fewer x-rays.  If IM was caused in any meaningful way by the x-rays themselves, which are a very common procedure, we would expect to see a far higher incidence than a doubling of the above tiny figures.  Remember that 2 x almost nothing = still almost nothing!

[niner]

Note that this study observes a link but does not claim causation.

 

Here's a perspective to help balance things out:  Incidence of Intracranial Meningioma is 0.008%, comprising mostly women.  Of these cases, over 90% are benign.  So incidence of malignant IM is less than 0.0008% = less than 1 person per 100,000 population.  This means: Don't worry about it.

 

Secondly, when studies are working with stats so fractional it's hard to interpret anything meaningful from them, least of all causation from a questionable correlation.  The overwhelming likelihood is that any true differences in rates of IM will be because those who require more x-rays are less healthy, in their genetics or health habits, than those who require fewer x-rays.  If IM was caused in any meaningful way by the x-rays themselves, which are a very common procedure, we would expect to see a far higher incidence than a doubling of the above tiny figures.  Remember that 2 x almost nothing = still almost nothing!

 

Very good points.  There are other explanations for the correlation-  People who get dental care are higher income, generally speaking, than people who don't get dental care.  That is going to introduce a ton of confounders into the equation.  Maybe something that higher income people do more often is the real cause of IM.  Honestly, the paper is such a steaming pile, you have to wonder how stuff like that gets published.  At least in the journal setting, it will be read by people who know how to interpret such data, but when it hits the media, it's pure sensationalism.