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Teeth and teeth care

teeth; tooth; dentist; toothbrush; enamel; toothpaste; permanent; brush; fluoride; sugar; starches; braces; orthodontist; orthodontia; piercing; stud; lip; tongue;


Why do we have teeth?

  • Teeth bite and chew food so that it is small enough to be swallowed.
  • Teeth help you to form words so that you can speak properly. You will have noticed that when young kids lose their front teeth, their voices sound quite different.

How many teeth do you have?

Your first teeth are called deciduous teeth. They may also be called milk teeth, baby teeth or primary teeth.

  • You have 20 deciduous teeth and they start growing into your mouth from about 6 months of age.
  • All 20 teeth have grown into your mouth by about two and a half years of age.
  • From about 6 years you start to slowly lose them.

Your second teeth are called permanent teeth (also called adult teeth).

  • You have 32 permanent teeth.
  • They are called permanent teeth because if you look after them you can have them for all of your life.
  • They begin growing through your gums from about 6 years and all 32 have finished growing into your mouth by about 18 –25 years.
  • The permanent teeth push out your deciduous teeth as they grow into your mouth.

Tooth eruption charts

When teeth grow into the mouth, this is called eruption. The American Dental Association has charts of when teeth erupt: 

What does a tooth look like?

Teeth have two parts:

  • The crown is the part of the tooth we can see in our mouths.
  • The root of the tooth is 'planted' into the jawbone to keep the tooth steady while it is doing its job.

Teeth have three layers:

  • Enamel, a hard protective outer layer covering the crown of the tooth.
  • Dentine, a second protective layer covering the nerve of the tooth.
  • Pulp (also called the nerve), the soft middle of the tooth that has a blood supply and nerve endings.

Why do teeth have different shapes?

Different teeth do different jobs.

  • Incisors are for cutting.
  • Canines are for tearing.
  • Molars and pre-molars grind up food until it's small enough to swallow

Looking after your teeth, gums and mouth

It is important to look after your first teeth and permanent teeth. Keeping your teeth, gums and mouth clean and healthy can prevent disease and infection, and can help to avoid pain and sickness. Also a clean healthy mouth feels nice, looks good and keeps your breath fresh.

Your teeth need to be cleaned really well every day. This is because germs or bacteria in your mouth grow on your teeth and around the gums every day. It is called dental plaque and it makes acids that attack the teeth and gums and cause disease.

If you keep your teeth clean and healthy, you will avoid problems like tooth decay, toothache, bleeding gums, yellow teeth and bad breath.

Tips for a healthy mouth, teeth and gums:

  • Clean your teeth well twice a day, after breakfast and last thing before you go to sleep at night. After a meal have a drink of water (this washes your teeth and mouth).
  • Use a small toothbrush with soft bristles. Hard and medium bristled toothbrushes can damage teeth and gums.
  • Use fluoride toothpaste. Spit it out when you have finished cleaning your teeth. Rinsing your mouth will wash out too much of the protective fluoride. 'Spit, don't rinse'.
  • Gently and thoroughly brush each side of every tooth and the gums. It should take about 3 minutes to do them all.
  • Avoid cleaning your teeth soon after drinking acid drinks such as orange juice. The acid in drinks softens the enamel, and cleaning can scratch the enamel while it is soft. Rinse your mouth with water, wait for about half an hour, then clean your teeth.
  • Dental floss cleans between your teeth, get your dentist to show you how to use floss.
  • Once a week you can check your toothbrushing skills by rinsing with a liquid called Disclo-gel*. This is a pink liquid that stains the plaque pink and makes it easier to see. Disclo-gel* can be bought from a chemist. If your teeth are not totally clean, there will be a pink stain on a tooth. Brush that stain off and remember how you did it, so that you can add that to how you clean your teeth.
  • Wash your hands after going to the toilet and before using your toothbrush.
  • Don’t start smoking. It stains your teeth and can lead to disease in the mouth.

Keeping your toothbrush safe from germs

  • After brushing, rinse your toothbrush under running water.
  • Store your toothbrush in a clean dry place.
  • Do not share a toothbrush, as this can spread germs.
  • Replace your toothbrush often.

How do teeth decay?

  • Germs (bacteria) in our mouth grow on teeth every day. They form a sticky layer over the teeth called dental plaque.
  • The bacteria in plaque use sugars in the things we drink and eat, and make acids. The acid attacks the tooth’s outer layers (enamel and dentine) and eats them away. For more information about sugar and starches in food, have a look at the pamphlet 'Sugar' produced by the South Australian Dental Service.
  • If acid continues to attack, then a hole will appear in the tooth's outer layer. This is called tooth decay (or dental caries). Tooth decay may be painful or you may not even know it is there.
  • Saliva neutralises the acid in plaque. If the plaque is brushed off and saliva surrounds the tooth, the enamel surface can harden again. Fluoride helps the enamel to be repaired.

If the tooth continues to decay, a number of things could happen:

  • The tooth could break.
  • The nerve or pulp could get infected and the nerve could die.
  • You could have a toothache.
  • You could get facial swelling.
  • You might feel sick.
  • You might need a filling.
  • The tooth might need to be taken out (this does not need to happen often now).

Tooth-friendly foods and drinks

  • Choose a wide variety of healthy foods every day.
  • Foods such as dairy foods (milk, cheese and yoghurt) have lots of calcium in them, which helps develop strong healthy teeth.
  • If you can’t have dairy foods, look for foods which have calcium added (some soy drinks have added calcium).
  • Don't have lots of snacks between meals, especially ones that contain sugars and acids. These cause plaque to build up on teeth, which can cause tooth decay.
  • Choose water as your main drink. Tap water is best because it contains fluoride which helps harden and repair the enamel surface of teeth. Rinsing out your mouth with water after you have had something to eat helps stop plaque building up too. Tank water and bottled water (spring water) don’t have fluoride in them, so they don’t protect teeth as well as tap water.
  • Where possible, choose medicines and cough lollies that are sugar free.


Are your teeth crooked and you are afraid you might need braces? Have a look at the topic 'All about orthodontia'  on the TeensHealth website.

Oral piercing

Having a piercing of your lip, cheek or tongue will affect the health of your mouth and teeth.

Have a look at the SA Dental Health Promotion fact sheet 'Oral piercing and your oral health'.

Did you know?

  • If you look after your teeth, you can keep them forever.
  • Teeth are the hardest part of your body.
  • Sharks have three rows of teeth, and they grow new ones if they lose any.
  • Fluoride was introduced into toothpaste in the 1970's.
  • Fluoride was introduced into the water supply in Adelaide in 1971. Kids in South Australia now have much healthier teeth than their grand parents had because the fluoride makes their teeth stronger.
  • If your family uses only rain or spring water, or you live in a country area that does not have fluoridated water, check with the dentist about using fluoride drops or tablets.
  • In the year 1770, the first toothbrush was invented and so were the first false teeth [made out of porcelain] by William Addis in England.
  • In the year 1790, John Greenwood of USA invented the dental drill. It was very big and heavy and the dentist had to turn a handle [like using a hand drill for drilling holes in wood] to drill out all the bad bits in the tooth. It was a very slow and painful process and people only went to the dentist when they couldn't stand the pain of toothache any longer!

It must have been a bit terrifying to go to the dentist in the olden days. Nowadays it is very different.


South Australia



Written with the support of the Health Promotion department of South Australian Dental Service 

American Dental Association 

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The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor or other health professional.
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