Brushing your teeth is still controversial

A pretty graph

All time BIO230 blog stats since mid-2011. The two peaks to the right are due to two days only, November 30 and December 1, 2013.

Thanksgiving Break is generally a quiet time around the BIO230 blog site, as the major visitors are spending time away from the Internet and Microbiology to spend time with their loved ones. Imagine my surprise to open my email over break and see that there were multiple comments to the blog! Student engagement! Discussion! Microbiology talk even when a grade isn’t on the line! However, when I scanned the comments in moderation, I didn’t recognize any of the names, and furthermore they were all for a posting that I had put up almost 3 years ago. What had happened was this: @joedevon who is tech writer and developer based in California came across my posting from 2011 describing the competing commensal relationships between different Streptococcus species in the human mouth.

In the article, I was trying to point out that the web of interactions between microbes is complex, but we could conceivably tweak the interactions in our favor to promote good oral health. @joedevon found my posting via a Google search, and posted the link to the web headline aggregator Hacker News. This lead to an approximately 1000-fold increase in the number of people visiting the blog. The previous best day was in November 2011 on a day that had both a lab report due and a bonus opportunity on the blog, and there were about 120 hits from students that day and I have never come close to that number a second time. November 30, 2013 had almost 12,000 people, several of whom left comments on the blog.

Two commenters remarked about the tenacious nature of biofilms, and the difficulty of removing them. From Craig:

There’s a perfectly good, and reasonablylow-tech, way to break up dental biofilms: using irrigators like Waterpik, or similar gizmos made by Panasonic, Phillips and others. These things are really needle-jet pressure washers that blast apart biofilms that toothbrushes or floss can’t touch, on even the most unexposed dental surfaces.

and from Clay:

Green Tea is the best thing you can do other than floss and brush and maybe use an H2O2 mouthrinse. Green Tea basically disolves the plaque, and does so very effectively indeed.

Biofilms are indeed difficult to remove, and the act of physically brushing does indeed work to break them apart.

Several commenters remarked on the hold that Big Dental has on Western Society, offering insights into the controversy that public health measures bring. From Transfire:

This has been worked out before at the university of florida. It has been possible to all but eliminate cavities for ten years, but $ talks, cures walk.

and these from  GogglesNinetynine and Smokes:

There is little evidence that consumption of fluoride increases tooth strength or promotes enamel growth. This is junk science that is forced on citizens because the “nanny” knows best.

…google truth about water flouridation.. it destroyes our teeth…fortunately there are companies now that started making toothpaste without flour in it…

I would point out to Smokes that gluten-free toothpaste is very important for our friends with Celiacs disease. Wait, I don’t think that’s what he meant. I’m sorry guys, but there is a phenomenal body of epidemiological data supporting that small amounts of fluoride promote dental health. The conspiracy argument suggesting that the money involved in prophylactic fluoridation campaigns is somehow lucrative just doesn’t hold water. Look, your average dentist will make far more money from extensive oral reconstruction than he or she does with a twice yearly polishing.

Biofilm

Biofilm (Photo credit: AJC1)

One commenter who passed my moderation test actually spoke to the topic which the original blog post was about; that is, is it feasible to tweak the complex interaction of microorganisms in the mouth to our advantage? Here is a link back to my conversation with Jonathan in the original post. His comment about the diffusion barrier that a biofilm presents is an interesting concept to think about. I think that small molecules might easily pass in and out of a biofilm, however larger molecules might have more of a problem.

This then shows a difficulty with one approach I put forward 3 years ago, where the use of an enzymatic mouthwash to dissociate biofilms that have formed requires that the enzymes have access to the biofilm material. If the biofilm represents a diffusion barrier for large molecules, the enzymes in the mouthwash would need to chew up the biofilm from the outside in, which might not be the most efficient method. Regardless, the tried and true methods of biofilm dissociation likely remain the best options for the foreseeable future.

BONUS: for those that have read down this far, list an organism (at least to the Genus level) that is part of the normal microbiota of the human oral cavity, and include a link to where you got that information. UPDATE! I have finished adding points into Blackboard, so I am calling time, thank you for playing!

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About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on December 6, 2013, in Bonus!, Rant, The more you know. Bookmark the permalink. 18 Comments.

  1. Interesting article but I’m still brushing my teeth.

    Actinomyces odontolyticus (suppose to be italicized but I can’t figure out how to do that from my phone)

    http://www.uiweb.uidaho.edu/micro_biology/250/Week10.pdf

    • To italicize, you have to put HTML tags around the text to be italicized. It would be typed like this:
      <em> text to be italicized </em>
      which becomes
      text to be italicized

  2. Actinomyces odontolyticus

    I see you edited it! But I still wanted to try it out.

    • I had to put in sooper sekrit html characters, so that my demonstration would actually display the “greater than” and “less than” symbols, and not just put my example in italics.

  3. Very interesting article, I like the gluten-free joke! I think I’m gonna keep brushing my teeth though.

    Streptococcus salivarius

    http://en.m.wikipedia.org/wiki/Streptococcus_salivarius

  4. Katrina Stefanik

    Streptococcus mitis

    Found this in your everyday read :
    http://jcm.asm.org/content/43/11/5721.full

  5. Katrina Stefanik

    It’s talked about in the results section!

  6. Courtney Gladstone

    Aggregatibacter actinomycetemcomitans

    http://www.antimicrobe.org/new/b72.asp

  7. Streptococci predominate http://myplace.frontier.com/~dffix/medmicro/normal.htm
    woop woop thanks Dr. S you da best! (made a rhyme there).. This made me want to start brushing my teeth 😉

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