Scientists figure out structure of enzyme that causes plaque to stick to teeth

Scientists have modeled the structure of the enzyme used by the dirty rotten Lactobacillus reuteri bacterium to attach itself to tooth enamel and cause cavities. "This knowledge will stimulate the identification of substances that inhibit the enzyme. Just add that substance to toothpaste, or even sweets, and caries will be a thing of the past."
teeth-cavities.jpgThe University of Groningen researchers analysed glucansucrase from the lactic acid bacterium Lactobacillus reuteri, which is present in the human mouth and digestive tract. The bacteria use the glucansucrase enzyme to convert sugar from food into long, sticky sugar chains. They use this glue to attach themselves to tooth enamel. The main cause of tooth decay, the bacterium Streptococcus mutans, also uses this enzyme. Once attached to tooth enamel, these bacteria ferment sugars releasing acids that dissolve the calcium in teeth. This is how caries develops.
Tooth Decay to Be a Thing of the Past? Enzyme Responsible for Dental Plaque Sticking to Teeth Deciphered
Photo by Shakespearesmonkey. Creative Commons Attribution 2.0 Generic license.



  1. “[…]Just add that substance to toothpaste, or even sweets, and caries will be a thing of the past.

    Do they mean “cavities”?

    Also, sweet!

  2. Dental caries, also known as tooth decay or a cavity, is a disease where bacterial processes damage hard tooth structure.

  3. I am not a microbiologist, but a quick Google search indicates that L. reuteri is naturally present in lots and lots of healthy animals, and studies seem to show that it has positive effects for both our immune and digestive systems.

    I’m SURE screwing with this “dirty rotten” bacteria would have no unforseen and tragic consequences in humans and other animals. Nope. No chance.

  4. They’ve had a bacteria that preys on the tooth destroying bacteria for decades. No one’s ever found anything wrong with people who’ve had some sprayed in their mouths and they never get cavities again. The same thing will happen with this. The dentists will study it for a century or so and then announce that it “needs more study”. Too much money in cavities.

  5. Growing up on ’60s and ’70s sci-fi, I always assumed that vaccines would end the caries menace. If the yet-to-be-discovered inhibitor also works against Streptococcus mutans and the other bacterial culprits this could be a nifty tool…in developed societies where the inhibitor can be universally added to processed foods and health aids. For those who live closer to the land (subsistence farmers), a once- or twice-a-life vaccine seems more practicable.

  6. Anything that displaces my private coral reef is probably a Good Thing. I don’t mind the bugs being in my system (I’ve always thought of myself as a colony animal anyway), but let ’em settle somewhere less damaging.

  7. “Just add that substance to toothpaste, or even sweets, and caries will be a thing of the past.”
    This statement is patently ridiculous to anyone with a most basic knowledge of microbiology. Any inhibitor of this enzyme will face the same problems as antibiotics face now; bacteria just aren’t that easy to beat. They mutate.
    If you tried applying this inhibitory molecule universally, you’d very quickly see the bugs develop resistance; there are a bunch of ways they might do this, and a bunch of ways the genes for this resistance would spread amongst the bacterial community.
    There are ten times as many bacterial cells than human cells in and on your body. Your mouth is a cushy environment, and they’re not going to be driven out of there just like that.

    I could go into detail. For example, alot of bacteria now produce enzymes that destroy antibiotics called beta-lactams (a broad class including penicillins, cephalosporins etc). There are more than 400 permutations of these enzymes described.
    But scientists have developed inhibitory molecules to these enzymes… Not so easy; alot of bacteria now produce enzymes that “…have broad-spectrum activity against both cephalosporins and penicillins and are not inhibited by conventional beta-lactamase inhibitors such as clavulanic acid and tazobactam…”
    This isn’t an unusual case. Bacteria evolve quickly and this gives them a massive advantage in the battle against our biochemical attacks.

    A good review can be found here…

    P.S. I must echo this sentiment: [CITATION NEEDED]

    1. You’re halfway there.

      See, going another step, there’s a good chance that latching onto the dental substrate is not completely critical to the survival of the bacterium. If it’s easier to develop an alternative living strategy than to develop an alternative enzyme to preserve the old one… well, bacteria aren’t what you’d call sentimental. The problem isn’t their presence, but the very specific strategy that they’re using at the moment.

      I’d say this will probably be much less fertile ground for developing resistance than antibiotics provide. You’re only constraining a single niche, rather than carpet bombing. The thing with antibiotic resistance is that if a bacterium develops it, it has an advantage compared to all its neighbors, because they’ve been similarly wiped out. Even a basically harmful mutation, as long as it provides resistance, is worthwhile.

      Here, however, the bacterium still has to compete with the rest of the assorted mouth fauna to survive, but this niche now has a pretty serious limitation, and one that we’ve been evolving for quite a while to limit. The form of this enzyme has been hashed out over vast generations of back and forth between mammalian teeth and bacterial colonies.

      This may give us a bump, and reduce the competitiveness of this niche bacterium. It’s like the native species side of the invasive species problem: The newcomers have escaped their predators, pathogens, and parasites, and suddenly, they’re much more fit!

      Anyway, I’d say less likely, and despite ridiculously widespread adoption of antibiotics, it took fifty years for it to become the massive problem it is today. If we get that many years of good teeth, it’s probably worth it. By then, they’ll grow me new ones! Which is pretty much what I’m banking on anyway, what with my crap enamel.

      …Of course, I’d also be really entertained if bad teeth became a disease transmitted mouth-to-mouth, as resistant bacteria slowly develop and begin to spread through the population.

  8. Also, since one does the publication of the crystal structure of a fairly obscure enzyme get this kind of coverage anyway?
    Taking a look at a paper like this seems a bit more interesting.
    I can think of a catchy headline:

    Red Wine could stop nasty bacteria escaping the gut, scientists report.

  9. You make some good points. But I think you underestimate the how great a niche the dental surface is. It has really great advantages over the other parts of the mouth, which are constantly getting shed and swallowed. Any bacteria that manages to survive on the enamel already has a competitive advantage over all it’s neighbours; it can hang on in this highly nutritious environment.
    Antibiotics might be ridiculously widespread, but not so much so that they’re found in toothpaste and sweets. That kind of omnipresence would really put on the pressure for resistance to develop. Also, you might think resistance to antibiotics has been fairly sluggish. But resistance to the enzyme inhibitors I mentioned has developed over a shorter period, because it’s comparitively easy for bacteria to modify a pre-existing enzyme than develop resistance from scratch to a class of deadly molecule they may never have encountered before. And despite considerable efforts, this resistance has spread from a small percentage to a majority of hospital-acquired strains within a decade (at least in the UK).
    It’s hard to know quite how quickly resistance would develop and spread; perhaps we might be able to keep ahead of most of it by constantly changing our weaponry. But just this weapon, just targeting this enzyme… I don’t think that’ll be enough. It’ll probably help a few people for a while, and I’d be glad. But it won’t eliminate caries for good.

    I would make the prediction that medical technology will eventually make caries a thing of the past, because there’s a ton of possibilities what with nanotechnologies and an increasingly intimate knowledge of the whole range of ways that caries make their progress. But I don’t think this’ll be the way to do it; it’s an instrument that will quite easily be blunted by evolution. And I don’t think a sterile dental surface will be smiling at me any time soon.
    Am I about 90% of the way there now? My point was that that the quote from the article is a terribly simplistic exaggeration of what a substance might be able to achieve. I didn’t mean to suggest it’d be completely useless.

  10. There are many documented cases of human beings who are completely immune to dental caries. There are also (fewer) documented cases of human beings that can regenerate teeth indefinitely; I seem to recall the record is five times. I know a woman who is on her third set of natural teeth, in fact, due to a fairly hideous accident that knocked all her upper teeth out.

    Interestingly, these cases are less common in technologically advanced societies. As soon as you start fluoridating the water and providing access to dental care, the sexual selection against bad teeth stops operating (sexual selection is the primary source of evolution in humans, according to Darwin) and the larger population of people without immunity to caries swamps the smaller immune population genetically.

    If we were willing to let the next couple hundred generations suffer with untreated tooth decay, natural selection would solve the problem for us.

  11. Teeth are a neat control mechanism for controlling the substances we put into our gut. If you eat a lot of foods that cause tooth decay (today) then perhaps your gut (and body) will suffer the effects.

  12. How about try just eating better?

    Although not totally unknown, it seems from my research that cavities (at least the number most people seem to get) are a modern disease.

    1. What do you mean by “modern?” Queen Elizabeth’s teeth were black with rot due to her fondness for sweets. “Sweet salt” (cane sugar) has been available in Europe since the Crusades.

      1. Roughly: heavily processed “European” food.

        Certainly the queen would have had the most access to such food (i.e. white flour, sugar). For sure some of this stuff has been available for centuries, but are you seriously comparing the amount of sugar available to most people in the 1000’s to now?

        And it’s not like diet is going to completely eliminate cavities, just drastically reduce them…

  13. I don’t think a lack of selection for healthy teeth over a few generations would really have such an effect on our genetics in such a short time so as to make our population susceptible and less developed countries not so. The thing is, caries probably don’t impact on fitness that much overall, although a small percentage of people have died from the complications.
    Alot of primitive societies have suffered from caries to, but mikewarren’s right, it’s mostly about diet. Now we have tons of sugar and juice and coke and stuff.
    But even thousands of years ago, Wiki says… “Associated with the introduction of domesticated and processed plant foods, such as cereal grains, in the human diet, there was, in many areas, a general decrease in body stature and dentition size, and an increase in caries rates..”
    (It’s referenced too)

    “If we were willing to let the next couple hundred generations suffer with untreated tooth decay, natural selection would solve the problem for us.” That probably won’t happen… and it wouldn’t be worth it. Anyway, by your logic we’d be free of acne and backaches and eye strain, not to mention the whole bunch of women who would’ve evolved out of their tendency to die whilst trying to give birth. All that in only a few thousand years of natural selection. Natural selection’s already known us for millenia and all it’s come up with is this.

  14. Xlyitol, used every day in the correct amount, will create a PH environment in your mouth that these teeth-eating bacteria cannot survive in. I have been using the toothpaste, gum and little lemon drops for several months now and must tell you it works as long as you keep it up- I have no plaque/tarter buildup. My daughter who’s getting her bachelor of science in dental hygiene told me about it and she’s right. You can find these xylitol-containing products at health food stores and on the web if you just type in xylitol toothpaste.Xylitol is naturally derived from plants, originally from the xylum of birch trees but now also from other plants, and the most amazing thing is that it tastes like clear, clean sugar so it’s pleasant and makes your toothbrushing and gum-chewing feel like it’s wrong somehow.

  15. I have not read through all of the responses but something tells me someone has already called this out:

    1. bacteria adapt and evolve. introducing a protein “into the environment” that causes this bacteria to not stick to enamel will only make it stronger (in some cases). who’s the say the bacteria won’t evolve into something that eats away at your gum or your mouth?

    2. anything that goes into our mouth most definitely ends up in our digestive tract. is this protein good for our digestive tract? what about the bacteria that is in our digestive tract?

    3. the best way to minimize plaque and reduce cavities is…
    BRUSHING AND FLOSSING YOUR TEETH AFTER YOU EAT! look at that. we already have a solution that is cheap, easy, efficient and “environmentally” friendly.

  16. In order for tooth decay to occur, three things are necessary:
    Now the first two are desirable and good. The third item is the bad guy, and it can be removed with no harm to the body. Therefore, if one cleans food from one’s teeth within 20 minutes of eating, decay cannot occur. Proper cleaning requires both thorough brushing and flossing. Brushing should last at least 2 minutes and flossing should be done especially before bedtime. Never go to bed with food on the teeth as bacteria love to operate in a dry environment as we often present when we sleep.
    If this sounds sensible, I will tell you it is successful which I can confirm from my 40 years of dental practice.

  17. Stop EATING SUGAR and MEAT!!!!!!- These bugs help you digest food elsewhere. Stay away from those 2 and your teeth will be fine.

  18. What the article misses is that the key substance is already being used, and has been for the past 40 years in countries like Finland. And it doesn’t interfere with the enzyme, which would be tricky and open a potential flood of unintended consequences as prior commentators have correctly warned. And for pauliswhoiam xylitol works, not by killing the bacteria, but by just blocking their ability to hold on. It also allows strains of bacteria, both S. mutans and L. reuteri that do not elaborate the acid and cause tooth decay, to multiply and provide their beneficial effects. It is totally in line with the concepts taught by Paul Ewald in his book, The Evolution of Infectious Disease, which shows how blocking transmission pressures bacteria to adapt in more benign ways. Using Ewald’s model allows us to see how much adaptation takes place. That story is in: The Boids and the Bees: Guiding Adaptation to Improve our Health, Healthcare, Schools, and Society.

    Xylitol is a very handy molecule: 2 grams, 5 times a day and 80% of cavities don’t happen 9bottom line of 40 years worth of clinical studies); put it in your nose regularly and it optimizes your own nasal defenses. A clean nose means less allergic and infectious probelms. Read No More Allergies, Asthma or Sinus Infections for the whole story.

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