Hello, my name is Mrs. Mehrin, and I'm so excited to be learning all about looking after our teeth.

And today we are going to be planning and doing.

Let's begin.

Welcome to today's lesson from the unit Introduction to the human digestive system.

Your lesson outcome for today is: I can investigate what damages teeth and how to look after them.

Now, I know that sometimes learning can be a little bit challenging, but that's okay because it just means that we're going to work really hard together and we are going to learn lots of fabulous new things.

Now, here are your five keywords for today.

I am going to be referring to these words throughout today's video, so you don't need to jot them down.

However, if you feel that it does help you, you can jot them down by pausing the video now.

Off you go.

Fantastic, well done.

Now here are the five definitions for those five keywords.

Again, I am going to refer to these definitions throughout today's lesson.

However, if you feel that it's helpful for you, you can pause the video now and jot these down.

Fantastic, well done.

Now our lesson today is split into two parts.

Let's begin with the first one, looking after our teeth.

Lucas is thinking about how many sets of teeth humans have in their lifetime.

And Lucas says, "I think human teeth keep growing back whenever one falls out." What do you think? I'll give you five seconds to think about your answer.

Fabulous, well done.

Now, humans have two sets of teeth.

They have deciduous teeth and permanent teeth, and deciduous teeth are the first set of teeth you have as a child, or sometimes we might call these baby teeth or milk teeth.

And then we have the permanent teeth.

Deciduous teeth fall out and are gradually replaced by something called the adult teeth, and these are permanent.

Now, humans usually have 20 deciduous teeth, followed by 32 adult teeth in their lifetime.

So let's do a quick check-in of your learning.

How many sets of teeth do humans have in their lifetime? Is it A, humans can just grow as many teeth as they need if they are damaged, humans have two sets of teeth in their lifetime, humans grow one set of teeth when they are born and keep them all of their life? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

The answer is B.

Humans have two sets of teeth in a lifetime.

Now, teeth are made from different parts.

Enamel is a very hard, shiny surface that protects the tooth, and you can see that when you smile.

So you can have a look in the mirror and if you smile, you'll be able to see that really hard, shiny surface, and that's called enamel in your tooth.

Now, dentin is the hard second layer of the tooth.

And the gum surrounds the tooth.

So the gum is the pink bit around your teeth.

Now, nerves and blood supply keep your tooth alive.

The jawbone holds the roots, and the roots hold the tooth in place.

Now, the hard white enamel on our teeth is like a suit of armour that protects the softer part of the tooth underneath.

And you might notice that sometimes you have a sticky, pale yellow substance called plaque, and that forms on your teeth and your gums when you eat and drink.

And plaque is made up mostly of germs. And a build of plaque can damage our teeth.

Now, when teeth become damaged by a buildup of plaque, they gradually break down and they rot away.

And this is called tooth decay.

So this tooth now has a hole in it due to tooth decay.

Now, if the tooth is not filled by the dentist, the hole can get bigger and the tooth may need removing.

So the enamel on this tooth has worn away, leaving a hole or a cavity.

The hole has been filled by a dentist to stop the decay.

And that's that silver part there that you can see on the tooth.

So let's do a quick check-in of your learning.

Which of these are signs of tooth decay? Is it A, a buildup of plaque; B, smiling; or C, a filling? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is A and C.

True or false? We don't need to remove the plaque from our teeth as the strong enamel will protect it.

Is that true or false? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is false.

The enamel will not protect your tooth, or your teeth, I should say, from the plaque.

Now, is it because plaque is going to damage even strong enamel if it's not removed, or B, plaque doesn't cause our teeth harm, it just makes them even stronger? Again, I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is A, plaque will damage even strong enamel if it's not removed.

Now, Lucas says, "I don't want plaque to build up on my teeth and cause decay.

So how can I look after them?" So to look after your teeth, first of all, you need to be visiting the dentist for regular checkups, and that's usually at least twice a year.

And the dentist can spot signs of tooth decay and help to remove a buildup of plaque.

Now, if you go to the dentist and they say that you need to come a little bit more regularly, that could be just because there may be some issues in terms of a buildup of plaque and they just need to keep an eye on that.

But usually it's twice a year.

Now these things can also help you to keep your teeth healthy.

So do you know how? Have a look at the three things or the four things I should say that are there.

We've got toothpaste, toothbrush, mouthwash, and dental floss.

So how can we use these things to keep our teeth nice and healthy? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

So a toothbrush is used to remove plaque from teeth.

So you should be brushing your teeth twice a day, once in the morning when you wake up, and then again just before bed.

Fluoride toothpaste helps to remove stains and strengthen the enamel of teeth.

And you can check whether or not your toothpaste has fluoride in it, or a good amount of fluoride, by having a look at the packaging.

Mouthwash is really important because it helps to kill germs in your mouth that can mix with food and cause the plaque.

And dental floss is used to remove plaque between your teeth.

So when you are brushing, your toothbrush is not going to get into all of the areas of your teeth, especially in between the gaps of your teeth.

So flossing will help to get rid of any plaque that might be there in between your teeth.

So which of these people should you visit regularly to keep your teeth healthy? Is it A, an optician; B, a doctor; C, a dentist; or D, an audiologist? So I'll give you five seconds to think about your answer.

Off you go.

The answer is C, the dentist.

Well done.

Which of these things could you use to keep your teeth clean? Would it be A, a hairbrush; B, toothbrush; or C, fluoride toothpaste? So there could be more than one answer here.

I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is B and C.

Now here is your first task for today.

I want you to imagine that you are a tooth.

I want you to describe what needs to be done to you to keep you clean and healthy.

So you could start with: to look after me, you should.

So you could start with: to look after me, you should.

Okay, so I'd like you to pause the video here and have a go at that activity.

Off you go.

Fantastic, well done.

So you may have got something similar to this.

So to look after me, you should brush me twice a day with a fluoride toothpaste to remove the plaque from my enamel surface.

Rinse me with mouthwash to remove the germs that can cause plaque.

Floss in between me and other teeth and the gums to remove any bits of food or plaque.

Ask a dentist to examine me and check I have no tooth decay at least twice a year.

Fantastic, well done.

Now we are onto the next part of our learning, investigating tooth decay.

So Andeep says, "I brush my teeth twice a day and visit the dentist, but I still had to have a filling in one of my teeth.

I wonder why." So Jacob says, "I think it depends on the type of food we eat." And Izzy says, "I think sugary foods and drinks are bad for your teeth." What do you think? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

So scientists have discovered that different types of food and drink can contain lots of sugar.

Sugar in food and drink mixes with germs in your mouth, causing the plaque to form on your teeth.

And the sticky plaque breaks down the hard, white enamel protecting your teeth, and this can lead to tooth decay.

Let's do a quick check-in of your learning before we carry on.

Which of these things can cause tooth decay? Is it A, talking too much; B, eating too many sugary foods and drinks; or C, brushing your teeth twice a day? So which of these things can cause tooth decay? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is B, eating too many sugary foods and drinks.

Now scientists have carried out investigations into which drinks are harmful to teeth and cause tooth decay.

So we've got water here, fresh orange juice, cola, blackcurrant cordial, and diet cola.

Now which of these drinks do you think have the most sugar in them? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So these children plan to carry out their own investigation and the question is, which drinks are most harmful to our teeth? Izzy says, "We can drink lots of different types of drinks and observe which ones cause tooth decay." Now is there a problem with Izzy's idea, and why? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So Andeep rightfully said that we don't want to damage our own teeth by doing this experiment.

So I wonder what we could use instead that is like a tooth? What do you think they might be able to use? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So Jacob says, "My dentist said that eggshells are made from a similar material to the enamel on teeth." Isn't that interesting? Izzy says, "We will fill cups with the same amount of different drinks to make sure that it's a fair test." "And we'll place a clean eggshell in each drink and leave it for a week.

And we will make observations of the eggshells to find out which have been damaged the most." And here we have a picture of the eggshell in the drink.

Now let's do a quick check-in of your learning.

What might scientists do to investigate which drinks are harmful to teeth? Is it A, to taste the different drinks; B, use eggshells instead of teeth and leave them in drinks; or C, ask different people what drinks they like best? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is B, to use eggshells instead of teeth and leave them in drinks because it's similar to the enamel.

Now here is task B.

It says, use your own ideas, or Izzy and Jacob's plan, to carry out your own investigation to find out which drinks are most harmful to teeth.

You might need different drinks, cups, measuring jugs, and clean eggshells.

Now what do you predict will happen and why? I want you to now have a go at this activity and then to pause the video and then come back once you're ready.

Off you go.

Fantastic, well done.

Now, now that you've done your prediction, you're going to need to leave the investigation for up to a week in order to observe the results.

So to investigate which drinks are most harmful to teeth, I have chosen to use cola, diet cola, fresh fruit juice, water, and blackcurrant juice.

I predict that the cola will damage the eggshell the most because cola contains lots of sugar.

I think the fruit juice is healthy for teeth, so it will cause the least damage.

And I will observe my investigation for five days and record what happens to the eggshell using photographs.

Now we are onto the summary of your learning for today.

Humans have two sets of teeth in their lifetime.

The teeth you have as a child are replaced by adult teeth.

A buildup of plaque can lead to tooth decay.

To look after your teeth, visit the dentist for regular checkups and brush twice a day with fluoride toothpaste.

Food and drink that contains lots of sugar can cause tooth decay.

Scientists investigate which drinks are harmful to teeth.

Well done for your fantastic work on planning and doing an investigation.

Now you're going to be leaving that investigation for a week and then you're going to be recording what you see happening and I can't wait to see what results you have.

Again, I'd like to just say a massive well done for today.