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Medicine

Tooth Cavities May Protect Against Cancer 149

Posted by Soulskill
from the take-that-dentists dept.
Hugh Pickens DOT Com writes "John Gever reports at MedPage Today on a new study conducted by researchers from the University of Buffalo, which found that people with more cavities in their teeth are 32 percent less likely to suffer from head and neck cancers. 'To our knowledge, the present study suggests, for the first time, an independent association between dental caries and head and neck squamous cell carcinoma.' The researchers proposed a mechanism for the apparent protective effect: that cariogenic, lactic acid-producing bacteria prompt cell-mediated Th1 immune responses that suppress tumor formation. The team examined records of patients older than 21 seen in the university's dental and maxillofacial prosthetics department from 1999 to 2007, identifying 399 who were newly diagnosed with head and neck squamous cell carcinoma. Assuming that the association between caries and reduced cancer risk is real, the team suggests that one could regard the cariogenic bacteria as beneficial overall, with caries 'a form of collateral damage.' Therefore an appropriate strategy could be to target that effect specifically without aggressively targeting the bacteria. 'Antimicrobial treatment, vaccination, or gene therapy against cariogenic bacteria may lead to more harm than good in the long run.'"
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Tooth Cavities May Protect Against Cancer

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  • by dominux (731134) on Sunday September 15, 2013 @04:23AM (#44854793) Homepage

    or people who fail to take care of their teeth happen to do something else beneficial. I don't see a cause -> effect mapping between these observations.

    • by dutchwhizzman (817898) on Sunday September 15, 2013 @04:50AM (#44854857)
      The research suggests that the excretions of the bacteria and the bodies reaction to that are the cause -> effect mapping. However, your suggestion that toothpaste may have unknown carcinogenic properties could be just as valid.
      • by MightyYar (622222)

        X-Rays??? LOL. Seriously, people who go to the dentist more often get more of 'em.

        • by mcgrew (92797) *

          I've wondered whether or not a dentist's drill could set you up for more cavities, does it perhaps cause microscopic cracks from the vibration?

          At any rate I only see a dentist when a tooth hurts. I dislike having unnecessary ionizing radiation focused on my head, and dentists always want x-rays..

          • by lightknight (213164) on Sunday September 15, 2013 @09:46AM (#44855897) Homepage

            The X-Ray dose is trivial...especially the digital versions, which use, I believe, six times less radiation than a normal non-digital version.

            http://www.physics.isu.edu/radinf/dental.htm

            2 or 3 mrem is the reported dose for a dentist X-Ray.

            http://www.nrc.gov/about-nrc/radiation/around-us/doses-daily-lives.html

            On average, Americans receive a radiation dose of about 0.62 rem (620 millirem) each year.
               

          • by murdocj (543661)

            I sure hope you don't fly then. One article said you get the equivalent of 1 to 2 chest x-rays on a long haul flight.

            • by MightyYar (622222)

              I'm not a radiation-phobe. I was just pointing out that there could be something besides mouth bacteria at play. I didn't see dental x-rays accounted for in the study and that seemed like an obvious one.

            • by mcgrew (92797) *

              It's been 30 years since I've been on a plane, but I'd fly if I needed to. I'm far more averse to the hassle than the radiation, it was bad enough before the TSA.

          • by Agent0013 (828350)
            Plus, some small cavities can go away. The dentist will recommend you get them filled right away of course. My wife didn't get hers filled and on her next checkup, the ones they were saying needed to be filled were no longer there.
        • So then wouldn't it be the opposite? People with cavities had to have an x-ray to have those cavities filled, so more cavities = more xrays. Those without cavities just brushed their teeth frequently = no X-rays.
      • by mcgrew (92797) *

        Other studies have shown a link between gum disease and heart disease. [webmd.com] So whether you don't want cancer or don't want a heart attack, brush your teeth!

        (The American Heart Association disagrees) [latimes.com]

        • by swamp_ig (466489)

          More to the point - head and neck cancer is very rare. Heart disease kills one in three.

          So reduce a very rare risk in order to increase a very common risk, plus suffer tooth decay as well? Seems like a pretty poor trade to me.

      • by gmuslera (3436)

        Not just Triclosan [wikipedia.org] is present in several toothpastes [drbenkim.com], but is also indiscriminate in what it kills. Not just kills the bacterias that cause the cavities, but all the others too, maybe including the ones that as a side effect, protect us from those cancers.

        The trend of using antibacterial products indiscriminately is affecting the ecosystems that we have in us, in the gut, the mouth, and other places where having a bacterial ecosystem is something good for our health. Yes, could be bad boys down there, but k

      • Which type of toothpaste? There are many.

        (If you're going to roll out "fluoride", then you'd probably need to dig out variations in head/ neck squamous cancers between regions with different natural fluoride contents in water.)

    • I agree. It could be the opposite, that whatever prevents cancer causes tooth decay. Or, that there is an accidental association caused by some effect not studied, like accidental, unknown bias in the selection of patients to study.

      This seems to be intentional fraud by JAMA, the Journal of the American Medical Association. The abstract of the JAMA Otolaryngology -- Head and Neck Surgery article calls the effect an "association".

      The abstract should carry a warning something like this: "This is just a d
      • Another question: Does Hugh Pickens get paid for promoting this Slashdot article? Did someone at Slashdot get paid for including it?
      • by mark_reh (2015546) on Sunday September 15, 2013 @08:26AM (#44855497) Journal

        "Once fluoride is incorporated into the teeth of children, the problem of dental infection by decay-causing bacteria is solved, because the pH required to cause decay in teeth that have fluoride included is never achieved by the bacteria."

        It doesn't work that way. I am a dentist and can guarantee you that even fluoride treated teeth and teeth with systemic fluoride incorporation can and do get cavities. I drill and fill them all day every day. Fluoride is only one factor in keeping teeth healthy. You still have to brush, floss, maintain a healthy diet, etc.

        • I feel uncomfortable with what you said, "I am a dentist and can guarantee you that even fluoride treated teeth...", because you jumped away from the subject, which was people who had fluoride during their entire childhoods, not "fluoride treated teeth". My understanding is that people who have had fluoride applied externally get some benefits, but not the complete benefits, which are far greater.

          If you felt a need to change the subject, maybe you know what you said is not reliable. For example, as a den
          • by mark_reh (2015546)

            I don't understand. Are you a dentist? And what does changing the subject line have to do with the reliability of what I am saying?

            I am confused.

      • by Anonymous Coward

        Except this is a medical journal (by one of the big four publishers) with a specific target audience of medical doctors.

        "Association" has a specific definition, doctors know this definition and would never confuse this article as stating a direct causal relationship. This definition is used throughout the medical literature (not just JAMA). From the journal's abstract (http://archotol.jamanetwork.com/article.aspx?articleid=1736930) they are merely reporting an unusual association.

        If you go and read literatu

      • Re: (Score:2, Informative)

        by Anonymous Coward

        JAMA is a publication by healthcare professionals, for healthcare professionals. Not for the public. In fact, very little of what is published in the medical literature can be interpreted without a broad understanding of physiology, pathophysiology, research design, and biostatistics. Your points against JAMA Otolaryngology are all based off of fundamental misunderstandings due to deficiencies in those areas. Let me address them not in the order you've brought them up, but from the "bottom up" so we can bui

        • JAMA is a publication by healthcare professionals, for healthcare professionals. Not for the public. In fact, very little of what is published in the medical literature can be interpreted without a broad understanding of physiology, pathophysiology, research design, and biostatistics. Your points against JAMA Otolaryngology are all based off of fundamental misunderstandings due to deficiencies in those areas. Let me address them not in the order you've brought them up, but from the "bottom up" so we can bui

      • by swamp_ig (466489)

        JAMA seems to be an aggressive organization that sometimes promotes financial success for doctors against the interests of the public.

        The JAMA is the journal of the AMA, the doctor's union.

        It exists to promote doctor's interests. If it wasn't doing so it would be doing the wrong thing.

    • by Shavano (2541114) on Sunday September 15, 2013 @06:11AM (#44855043)

      Flouride in our water is contaminating our precious bodily fluids.

      • Flouride in our water is contaminating our precious bodily fluids.

        Mandrake? Can you hear me Mandrake?

        • by MightyYar (622222)

          I can assure you it has not recurred, Mandrake. Women uh... women sense my power and they seek the life essence. I, uh... I do not avoid women, Mandrake. But I... I do deny them my essence.

    • by DragonTHC (208439)

      or perhaps sodium fluoride is carcinogenic.

    • by Guppy (12314)

      or people who fail to take care of their teeth happen to do something else beneficial.

      Here's another possibility beyond what people have already mentioned -- People with bad teeth may have less oral sex. No, I'm serious:
      http://www.hopkinsmedicine.org/kimmel_cancer_center/centers/head_neck/HPV_and_head_and_neck_cancer/hpv.html [hopkinsmedicine.org]

    • by xtronics (259660)

      Correlation does not show causation - did these so called 'science reporters' ever learn the scientific method?

      It could be that people that get cancer are more prone to cavities - or both are induced by a third factor or just another random correlation.

      Idiots are always reporting 'associations' and 'correlations' as if it proves cause and effect..

    • I recommend reading up on the Scientific Body of literature put forth by Gen. Jack D Ripper.
    • by hedwards (940851)

      They may be onto something with this.

      But it's also worth realizing that people with cavities are also more likely to have a dentist spending a prolonged period of time examining their mouths. And probably more time during each visit. Consequently having the dentist notice something on the x-rays that hasn't yet gotten to the point of being cancerous. I know I've had a biopsy done just to make sure that it was just a benign cyst.

      I also wonder what the data looks like if you normalize it for people that have

  • xrays (Score:1, Insightful)

    by Anonymous Coward

    haven't read TFA, but could also mean those who get their carries fixed have more bitewing x-rays, which increases radiation to the head.

    • by Shavano (2541114)

      haven't read TFA, but could also mean those who get their carries fixed have more bitewing x-rays, which increases radiation to the head.

      Because radiation prevents cancer???

      • by Guppy (12314)

        haven't read TFA, but could also mean those who get their carries fixed have more bitewing x-rays, which increases radiation to the head.

        Because radiation prevents cancer???

        He's saying that people who go to the dentist regularly (to get some cavities fixed) get fewer cavities overall thanks to better care, but they also get more dental X-rays. The amount of radiation in a dental X-ray is super-small and generally not considered a cancer risk; however, there's been growing use of Dental CT scans, which actually require a substantial dose to obtain.

        • by kencurry (471519)
          I think the hypothesis works better the other way: people who have fewer cavities because of regular dental checkups & regular x-rays, and are more prone to cancer in the head. Conversely, people who have more cavities are not taking care of their teeth, so less dental check-ups & x-rays.
    • by MightyYar (622222)

      Yes, they would need to account for extra dental care. It's also possible that people with fewer cavities see the dentist MORE often - that is, they take care of their teeth. This would make them more likely to floss, get regular cleanings, have tartar removed, get exposure to fluoride and toothpaste, and have regular x-rays. I'd bet this is an older population getting the cancers, so really we might be controlling for things they were exposed to years ago.

  • It seems that they did not control for exposure to fluoridated water. The article says "they had no data on the causes of missing teeth." It would be interesting to see if any clear results emerged from a study that did control for that.

    However, given the level of entrenched interest in water fluoridation, I suspect it would be difficult to find funding for such a study, at least in the US.

    • by AK Marc (707885)
      "previous work examining periodontitis, which found that infections below the gum line are associated with increased cancer risk."

      Gum disease causes cancer, cavities prevent cancer. I've not seen anything on fluoridated water in relation to the two, but it should address teeth only, and not the gums, so far as the tooth decay doesn't aggravate gum issues.
      • by MightyYar (622222)

        IINAD, but I seem to recall a study showing the tradeoff between people with acidic mouths and people with more basic mouths. The acidic mouths are more amenable to tooth decay, but less susceptible to tartar buildup and gum disease. The basic mouths tend to get fewer cavities, but they get more tartar and are more likely to see gum disease. Gum disease is inflammation, and inflammation gets tied to cancer.

        On the other hand, they controlled for very little in this study, it would seem. Fluoride, x-rays, fre

        • by AK Marc (707885)

          On the other hand, they controlled for very little in this study, it would seem. Fluoride, x-rays, frequency of dental visits, etc.

          They didn't intend to, and failing to control doesn't mean the correlation isn't valid. Almost always when something "new" is found, the initial study is flawed because it wasn't looking for what it found. But it's a starting point. There are probably already 100 studies applying for funding to look at this in depth. The person that finds the causal link will get published, and those that don't will fund their program for 2 years on the grant funds. We'll find out in about 5 years what a "proper" study

          • by MightyYar (622222)

            They didn't intend to, and failing to control doesn't mean the correlation isn't valid.

            I don't take issue with the study authors so much, but with the write up linked in the summary. The study is titled: "Dental Caries and Head and Neck Cancers". The conclusion? "There is an inverse association between HNSCC and dental caries. This study provides insights for future studies to assess potential beneficial effects of lactic acid bacteria and the associated immune response on HNSCC."

            That's fine. But then the writeup is titled: "Dental Caries May Protect Against Cancer". Um, what???

  • by Kaenneth (82978) on Sunday September 15, 2013 @05:23AM (#44854939) Homepage Journal

    ... Or is a common ingredient in toothpaste a carcinogen?

    • Maybe they don't get cancer because they die of heart disease first: Tooth decay can cause heart problems

      http://www.abs-cbnnews.com/lifestyle/11/25/10/tooth-decay-can-cause-heart-problems [abs-cbnnews.com]

      MANILA, Philippines - Far as your pearly whites may be from your heart, dental experts say a small dental problem can go a long way. In fact, keeping your teeth healthy may just save your life.

      -=-=

      You know what else protects against cancer? Alzeimer's disease. People who get cancer rarely get Alzeimer's, and people who get

  • Fine, take them at their word.

    (1) Use the targeted approach to get rid of the bacteria.

    (2) Immunize to provoke the Th1 response that prevents the cancer.

    Leave it to a DDS to do a study saying "cavities are good, and we should not take any rash actions which would reduce the customer base for dentists, and if you do, you are all going to get cancer and die".

    • Are there any good dentists in the UK? I used to think it was some antiquated stereotype that British people have poor dental health, but I've honestly never found a good dentist in the UK. And some of my dullest schoolchums went on to be dentists, eradicating confidence I might otherwise have in the profession's standards.

      • by mrbester (200927)

        If you pay for it, most definitely. It has been my experience that NHS dentists aren't nearly as good.

        • I've seen a private dentist nearly every time. And NHS dentists are just private businesses with an NHS contract, where the payments are shared between you and the government. Recent changes to payment structure have encouraged dentists to do slapdash NHS work, but even that's a symptom of the profession - contrast my GP, who already appreciates that he's well-paid, and actually spends his time maximising his productivity rather than squeezing out every last penny.

    • by mark_reh (2015546)

      Ah! The old conspiracy theory of dentistry!

      I can assure you, there is plenty of work for dentists without anyone having to try to promote cariogenic behavior. In fact, it is usually dentists who promote fluoridation of water as a preventive measure.

      Oh wait, I know, fluoridation of water is some sort of conspiracy too...

  • by m00sh (2538182) on Sunday September 15, 2013 @05:42AM (#44854967)

    On Wikipedia, it's written that head and neck cancer

    is strongly associated with certain environmental and lifestyle risk factors

    The article says,

    Other limitations included lack of data on potential confounders such as patients' diet and socioeconomic status

    Isn't the work conditions one of the biggest things you look at in a cancer study? In the case of dental study, also diet.

    Among 399 patients with head and neck cancer, current or previous dental caries were significantly less common than in 221 individuals without a cancer diagnosis,

    Something like smoking or chewing tobacco would increase cancer risks but lower cavities.

    • Or perhaps people who tend to get more cavities don't live as long (maybe even only for socioeconomic reasons) and thus are less likely to develop cancer?

      I have no reason to believe that's true one way or another, it's just another potential idea.
      • by umghhh (965931)
        It actually may be the case. This type of cancer is not very common and is strongly correlated with risk factors like tobaco, alco etc use, but also exposure to some ugly things like HPV etc.
    • by Rockoon (1252108) on Sunday September 15, 2013 @07:14AM (#44855231)
      The problem with cancer studies is that so many disagree with each other, and there are so many studies that nobody in the field has a good grasp of things in general. Because of this, there isnt even a theory of cancer yet.

      The U.S. National Cancer Institutes has resorted to hiring physicists such as Paul Davies [youtube.com] to try to get a better grasp of cancer, because the medical folk just arent getting anywhere. The video is in fact of Paul Davies giving a talk about the state of cancer research.
      • by MightyYar (622222)

        If I can't read TFA, do you think I can watch an hour-and-a-half video???

        LOL, thanks for the link. It will make a nice podcast :)

      • by Nate T (2879435)
        I like his analogy of American colonization as cancer.
  • by K. S. Kyosuke (729550) on Sunday September 15, 2013 @05:43AM (#44854981)
    Even if this mechanism is real, cariogenic bacteria can only be beneficial if you're certain that tooth decay and the associated problems (abscesses, sepsis, etc.) won't kill you off before you get a chance to get cancer in the first place. It's all fine if you have access to a reasonably good dentist, like a third of the world or so in the past century, but otherwise...just ask Ramesses II.
  • Screw you colgate ! I win.

    Ms Marsh, suck eggs :) (they prolly cause cancer)
  • They got so bad teeth that they can't even bite the dust.

  • tonsils? (Score:3, Interesting)

    by HybridST (894157) on Sunday September 15, 2013 @07:01AM (#44855199) Homepage

    How many of these people still have their tonsils? I recall reading in one of the journals, probably on arxxiv and phys.org too, that there is some supporting data showing essentially a second immune system just for the mouth.

    No link 'cause my google-fu is coffee fueled.

    • by Guppy (12314)

      How many of these people still have their tonsils? I recall reading in one of the journals, probably on arxxiv and phys.org too, that there is some supporting data showing essentially a second immune system just for the mouth.

      BTW, what people commonly refer to as "tonsils" are actually just the palatine tonsils, which are part of an entire loose "ring" of lymphoid tissue encircling the pharynx [wikipedia.org] that includes the pharyngeal tonsils (adenoids), tubal tonsils, lingual tonsils, and patchy bits of un-named Mucosa-associated Lymphoid Tissue (MALT) in between.

  • Observational Studies are no where near being true nor scientific. Sure they're part of the scientific process but they aren't themselves scientific at all. Clinical studies are required. You could just as easily say that Eating less sugar, thus having less tooth cavities, may protect against cancer, or how about brushing your teeth more often may reduces the risk of getting cancer. Please, for f**ks sake - stop taking shit out of context and drawing up conclusions. Has everyone forgot about the Nurses' He
  • by Nightlight3 (248096) on Sunday September 15, 2013 @07:23AM (#44855253)

    It may also be that people who take good care of their teeth, which includes regular dental checkups end up with more x-rays and more exposure to variety of viruses or bacteria which may be carcinogenic (such as HPV, cold sores). Another potential factor is carcinogenicity of the tooth care products, such as toothpastes and mouthwashes. These are couple possibilities that one wouldn't expect research by 'cavity industry' to consider.

    • by Reziac (43301) *

      Good point, and if it's the case -- we may see a decline in such cancers as disposable instruments become the rule (thanks to the risk of HIV transmission), rather than the old sterilize-and-re-use.

      Anecdote: before disposable instruments and drill heads, every time I went to the dentist I could *count* on coming down with the flu a few days later. But not once since disposable drill heads came along.

  • by jonnat (1168035) on Sunday September 15, 2013 @07:34AM (#44855303)

    Or, people with better dental hygiene and less cavities go with much more frequency to dentists, who nowadays won't touch you, even for simple cleaning, without taking X-rays.

  • by Sponge Bath (413667) on Sunday September 15, 2013 @07:58AM (#44855403)

    The hill folk in Deliverance were toothless and playing banjos. Maybe country music prevents cancer.

  • http://en.wikipedia.org/wiki/Sickle-cell_disease [wikipedia.org]

    This is a disease (an inherited disease, perhaps like dental caries) that conveys a fitness against something else that is more serious.

  • Floride causes head and neck cancer.....

  • by istartedi (132515) on Sunday September 15, 2013 @03:29PM (#44857873) Journal

    Are smokers likely to go in for more teeth cleaning and/or whitening treatments to remedy ugly teeth? Do they brush more to get rid of stains? That might explain the whole thing.

  • ZOMG! All those conspiracy theorists were right. Fluoride in our drinking water was a communist plot to destroy the fabric of our nation!

  • IS the problem.

    We're destroying the internal ecology we evolved with, and trying to develop drugs to treat symptoms that exacerbate the core problem.

    Because modern medicine doesn't work. There have been no amazing new discoveries that translate into improving the lives of everybody for a long time now for a reason.

Thufir's a Harkonnen now.

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