Episode 3 Operation Ouch!

-Are you ready for our Ouch Snips?

-Snip.

-Ouch!

-Exactly.

To find out why we have them and how they help us,

I'm meeting entomologist, Vince Smith.

We've got this parasite called a Demodex mite, and with these,

the older that you are,

the more likely you are to have them.

So let's see if we can find some.

Vince is scraping the skin around my eyes to try and collect enough gunk

to test, but he doesn't get much, so we go into my ear.

There's a good pile of gunk on there,

so let's see what we can find.

I'm sort of hoping he doesn't find anything.

-You're loaded!

-Ugh, look at that!

-Ugh!

-Wow.

It's moving!

-Absolutely incredible.

-That just came out of my ear.

In the daytime, those mites are

living inside the little follicles of your hair cell,

and then during the night-time, they come out and they're moving around,

trying to find all their mates.

So every night, there's a bit of a party in my ear.

# You better get this party started. #

So these mites are pretty disgusting, but actually,

they're not doing me any harm.

In fact, they're useful because

they help clean the gunk from your ear.

We're carrying around all of these passengers, and this is just

the start. There are many other human parasites that we've got, too.

Time to head to the lab to meet some of Chris' little passengers.

This time, not so friendly bacteria living in his mouth.

Ugh!

Does my breath smell bad?

Yes, it does, actually.

I'm not surprised. I haven't brushed my teeth in two days.

-But it's all for a good cause. Isn't it, Chris?

-I hope so.

In fact, it was my idea.

Whilst I've been brushing my teeth twice a day, as you should,

I haven't let Chris brush his at all for two days,

but it's all in the name of medical research.

-My teeth feel fuzzy.

-That's because Chris has a layer of plaque

building up on them. Open wide.

I'm going to show you why plaque isn't something you want a lot of.

When you go to the dentist,

you'll have had your teeth scraped like this.

-Going anywhere nice on holiday this year, Chris?

-No.

Oh, lovely, I've been there. It's wonderful at this time of year.

Ugh, Chris, this is disgusting!

Plaque is a mixture of food particles, acid,

and bacteria.

We've all got thousands of different bacteria living in our mouths,

and most of them are harmless,

but there are some bad ones that can

turn the sugars in the food we eat into acid.

And it's this plaque acid that's the real problem.

It eats away at the tooth enamel, and that's what tooth decay is.

-Please, can I have my toothbrush back now?

-Soon!

There's more to show you.

We're both going to rinse our mouths with a special blue dye that will

show up how much plaque we have on our teeth.

It's my brushed gnashers first.

Ta-da!

-Ha, you look really funny.

-You look funny.

Now, even though Xander's been brushing regularly,

you can see some dye has stuck to his teeth, and that's all plaque.

That makes me a bit worried,

because I haven't brushed my teeth for over two days.

-Ugh! Why did you do that?

-It was your idea.

Well, after a quick rinse with the blue dye,

it's time to check out the state of my un-brushed teeth.

Ugh!

There's plaque everywhere.

How did you let this happen?

And all that plaque has built up in just two days.

That's gross!

I feel quite disgusting.

-I would like my toothbrush back.

-Nope.

I want to get a much closer look at your plaque, Chris.

Look at this.

Wow! So, these bacteria are the ones that live in my plaque,

and although we can't tell which are

the good ones and which are the bad ones,

some of them are the ones that produce the acid that is rotting

my teeth right now.

Yes. And if you just leave plaque, it hardens like cement.

That's called tartar and it builds and builds.

It can damage your gums and give you rotting teeth that look like this.

Not a good look.

That's it. I've had enough.

I am going to brush my teeth.

No, he's not.

We've shown you that we are all carrying little passengers around

on our bodies. Most of them are there to help, but some,

like the bacteria you find in your mouth, eat away at your teeth,

which is why you need to brush twice a day.

-See you next time. BOTH:

-Bye!

-Bye!

-Bye!

-Bye. Bye.

BYE!