Meet the Micro Monsters in your Mouth

What are they? Can they cause tooth decay?
27 November 2018

Interview with 

Gordon Ramage, University of Glasgow Dental School




The reason why it’s so important to brush our teeth properly is all to do with the build up of plaque. But what actually is plaque, and why does it matter? Chris Smith spoke to Gordon Ramage from Glasgow Dental School…

Gordon - Plaque is a collection of microorganisms. Bacteria generally, which cooperate with one another, they antagonize one another and they produce slime and that slime sticks them to the teeth.

Chris - So plaque is basically bacterial slime?

Gordon - Yeah and I think the problem is that the general public would think about it as bits of food and I think what we have to do is try and get the message across, is that we have micro monsters in the mouth.

Chris - And what are these microbes actually eating on - are they just dining on what we eat?

Gordon - Yeah absolutely and I think our diet is hugely important, so I think we know an awful lot about things called streptococci and we know that when we eat sugary sweets and other products that they turn that sweet sucrose into slime and that helps them make them even more sticky.

Chris - And what about actually, because people say that you get this acid attack, so you eat some food, this feeds you but it also feeds your mouth microbes and they produce this acid surge. Where does the acid come from?

Gordon - Yeah, so because the bacteria are stuck there and the slime, they start to grow and by growing they produce carbon dioxide and that makes the acidity go even further down, so the pH goes really low. And once that pH goe really low, below below 5.5, then it starts to demineralize the enamel that you talked about earlier. So the bugs are driving the low pH, which then basically starts to erode the enamel and then causes caries and tooth decay.

Chris - How do the bacteria you have in your mouth actually determine your likelihood of getting tooth decay? If you have bacteria that are better at making more acid more of the time, does that mean you're more prone to more tooth decay than someone who doesn't have that?

Gordon - Well I think it really comes down to an individual. So we acquire groups of microorganisms when we are born and somebody for example who breastfeeds versus somebody who is born cesarean, might have a very different oral microbiome, so the types of organisms in our mouth. And we know quite clearly that that's an implication and how you may then go on to progress to dental decay or gingivitis or recession of the gum, bleeding of the gums, depending on the types of organisms you as an individual have will have a real bearing on what you get. Obviously environmental factors like what you eat are going to play a key role.

Chris - What about if you snog someone who has rampant tooth decay, but you don't know that, do you end up picking up their very sort of pro tooth decaying bacterial flora and do you then assimilate that into your mouth microbes and vice versa?

Gordon - Your oral microbiome, or the types of bugs you have the mouth, are dictated to you very early on in your life and as you progress through puberty and so on they'll change. You may acquire the same bugs the same way as if you shook hands with somebody you may acquire bugs to your hand but the likelihood of them staying there long term it's probably not overly likely. So it's quite difficult to acquire them unless you live with someone and their presence for a long time.

Chris - That's reassuring. Now what about actually in the same way that some people like to try to manipulate the bugs that live in their intestines in order to achieve better health, and these are both prebiotic, you eat certain foods that select for better bugs, but you can also take probiotics - you actually ingest certain classes of microorganisms believing that this may change the spectrum of bugs that live in your gut and this will improve your overall health. Can we do the same thing then for oral bacteria? Could we eat certain things or wash our mouths out with a mouthwash with certain suspensions of bacteria that would change the composition of bugs in the mouth and therefore change our risk of getting dental decay or gum disease?

Gordon - I think the concept is absolutely true. I think the ability to manipulate your microorganisms in the mouth with diet, so prebiotics, is probably more likely than probiotics, so giving alive bacteria in your mouth, is going to be very difficult and although there's a number of studies that are sort of suggestive that there are changes in your oral health parameters, they're very limited, so the evidence is pretty poor at this point in time. Not to say that it couldn't happen. There is a potential there.


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