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What happens to your teeth in Space?

If you don’t brush your teeth, you’ll get cavities. This is something everyone knows.  But what happens to your teeth when you go to space?


NASA has been studying what happens to humans who go to space for many years using the International Space Station (ISS). The ISS is located hundreds of kilometres above Earth and astronauts from all over the world travel there on rockets to conduct experiments and help us understand how to protect humans in space. So far, they have found that some not-so-great things happen to our bodies when we are up there. For example, bones become weaker and muscles break down.  

But why do these things happen to us in space? Part of the answer lies in the fact that gravity on the ISS is much weaker than on Earth. In fact, it is almost non-existent - we call it microgravity. This means that the everyday physics we take for granted on Earth changes. For example, fluids don’t flow (don’t believe us? Check this out!) - they float about until they meet another surface, which they then cling to. Another, not so great observation NASA scientists have made is that bacteria flourish in microgravity. This brings us back to our teeth. If fluid doesn’t flow and bacteria loves to grow, how do we protect our teeth? And that was it, we decided that this is what we wanted to study ourselves.

Next, we had to think of exactly what science question we wanted to ask and how to test it.

SHINSHINE planning, Katya Gvozdenko, Edward Brelsford

After tons of brainstorming and creative discussions about where to get teeth, we came up with our hypothesis –

If a tooth submerged in a bacterial sucrose solution decays in microgravity, then it is hypothesised that the tooth will decay differently from a tooth submerged in a sucrose solution on Earth. 


SHINE MicroCavity Team

Hopefully, what we find will be useful for future astronauts and help them keep their teeth clean and healthy!

Our experiment to test this hypothesis involves placing human teeth in a chamber and then pumping in fluid that the bacteria present on our teeth can feed on. To keep the bacteria alive long enough to reach the ISS, we’ll have to freeze dry them and reactivate them with special broth when they are in space. Over the course of about a month we’ll pump fluid into the tooth chamber to mimic someone eating and drinking, and see how the bacteria grow and if they produce lactic acid, which is what actually makes your teeth decay. Some of the teeth we send up will have a fluoride coating that retards bacteria growth and tooth decay. We have a special sensor that can tell us just how much bacteria is growing and we will take measurements from this throughout our flight. Once our experiment returns to Earth we’ll use a bone scanner to image the micro structure of the teeth and see if there is significant decay. To have something to compare our space teeth with, we’ll perform a control on Earth!


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