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Science.

And that is the same physics, medicine, nature, or space,, a brain, life, the universe.

Hello, this week we're filling the gaps in our knowledge of teeth.

We'll also meet the microbes in our mouths and we do an experiment to find out what is best electric or traditional

toothbrush. Plus in the news researchers grow new spinal discs in a dish we explore the

ghostly galaxy next door and scientists discover one of the largest

oldest structures on the planet.

I'm Isie Clark.

I'm Chris Smith and this is The Naked Scientists.

The Naked Scientists Podcast is powered by UKfast.co.uk. About one person in five suffers with a bad back and a common culprit is wear and tear to the

intervertebral discs that sit between the vertebrae that make up the backbone.

These discs act as fleshy shock absorbers.

They have a soft jelly-like interior

and a tough elastic outer surface.

But as we age, they stiffen, shrink and deform,

and they compress painfully on nearby nerves.

Artificial plastic and metal replacement discs are available, but these can also wear out.

So scientists at the University of Pennsylvania have been exploring how to grow new spinal discs in a dish.

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