Babies' teeth begin to develop before they are born, but in most cases don't come through until they're between 6 and 12 months old.
Most children have a full set of 20 milk or baby teeth by the time they're three years old. When they reach five or six, these teeth will start to fall out, making way for adult teeth.
Read more about baby teeth and how to tell if a baby is teething.
By the age of 12 to 14, most children have lost all their baby teeth and have their adult teeth.
There are 32 adult teeth in total – 12 more than in the baby set. The last four of these, called wisdom teeth, usually emerge later than the others, generally between the ages of 17 and 21.
Wisdom teeth removal
Wisdom teeth that don't come through properly, or at all, can be painful and it may be necessary to have them removed.
Read more about wisdom tooth removal.
What are teeth made of?
The part of the tooth that you can see above the gum is called the crown. This is covered in hard, shiny enamel. Enamel is the hardest substance in the body and protects the more sensitive inner parts of the tooth.
Underneath this is the dentine – a sensitive substance that makes up most of the tooth. Dentine is a hard substance, though not quite as hard as enamel.
Dentine protects the inner part of the tooth, called the pulp. The pulp is where each tooth's blood supply and nerve endings are found. The blood supply is what keeps the teeth alive and healthy. The nerve endings send messages to the brain, such as whether you're eating something hot or cold, or if you have a decayed or damaged tooth.
The pulp goes all the way into the root of the tooth, which is hidden under your gum. Cementum covers the root of the tooth, and periodontal fibres connect the tooth to the jawbone.
Types of teeth
There are four different types of teeth:
- Incisors. These are your four front teeth on the top and bottom jaw. They’re used for cutting and chopping food.
- Canine teeth. These are sharp, pointy teeth. You have one on each side of your incisors on your top and bottom jaw, making a total of four. They help to tear food.
- Premolars. Next to your canine teeth are your premolars (also called bicuspid teeth). You have eight premolars in total: four on your top jaw and four on the bottom. They are bigger and wider than your incisors and canine teeth, and are used for crushing and grinding food.
- Molars. You have eight molars: four on top and four on the bottom. These are your strongest teeth and work with your tongue to help you swallow food, mashing it up until it's ready to be swallowed safely.
Now, read about how to look after your teeth.