Teeth are small, calcified, white structures found along the jaws of most humans and animals.
Humans have two sets of teeth in a lifetime. Adult humans have 32 teeth. Humans first set of teeth are called milk teeth. Children have 20 primary (milk) teeth and generally these will have all been replaced by second teeth by the age of 13. This brand new set of second teeth will hopefully last until the end of your life! Teeth are among the most distinctive and long lasting feature of the mammal species. Wisdom teeth (also called the third molars) are molars that usually erupt from the ages of 17 to 21.
What is the function of each tooth?
The main function of teeth is to chew food. They are also used for defense or protection (biting attackers). Each tooth has a different function. The shape of teeth is often determined by diet. Mammals that only eat plants (herbivores) may have more molars for grinding. Animals that only eat meat (carnivores) may have more incisors for cutting or tearing flesh. There are four types of permanent (second) teeth in a human.
What are the types of teeth?
Incisors: which are used to cut food
Canines: which are used to tear food
Premolars: used to grind food.
Molars: also used to grind food.
You can download our free Learn about the Teeth science for kids worksheet and science for kids coloring sheet below
What is a tooth made of?
The tissue that seals the side of the tooth to prevent infection is called the gum. Teeth are fixed into jaw bones and are held in place by cement. The three main layers of a tooth are called enamel, dentine and the living layer is called the pulp. Enamel is the hardest material in the body. This hard mineralized coating covers an exposed tooth. It is normally grayish or white in color and is a very tough material.
The cementum is a layer of tough, yellowish, bone-like tissue that covers the root of the tooth.
The crown is the visible part of the tooth.
Nerve: This is what allows us to feel hot and cold. Sometimes when this root becomes too sensitive to hot and cold the dentist will kill this nerve. This procedure is called root canal.
What is a cavity?
A cavity is a fancy name for tooth decay. The mouth has colonies of bacteria (living organisms) on our teeth, tongue, lips and gums. Some of the bacteria is good and helps us break down food particles. However, some of these bacteria are bad especially when it attaches itself to hard surfaces like enamel and doesn’t get brushed away. When this happens this yellowish film is called plaque. Yuck! That’s way it’s so important to brush your teeth and not to eat too many sweets!
Why do some kids have braces?
Sometimes when kids are growing their teeth don’t grow right. Braces are used to correct such things as underbites, overbites, cross bite and open bites, deep bites, or crooked teeth and various other flaws of teeth and jaws, whether cosmetic or structural. Sometimes even adults must get braces!
Braces do an amazing job. Over time, they actually move your teeth. This movement is achieved by putting pressure on the tooth to be moved by stretching the tissues surrounding it. The socket then becomes looser, which loosens the tooth temporarily. The bone will eventually fill in around the tooth in its new position, solidifying it in that place.
How do we keep our teeth healthy?
Our teeth have to do us a long time. So, it’s important to brush your teeth twice a day. Once in the morning and then at night. Otherwise the plaque will eventually build up, corrode and rot your teeth. Don’t forget to floss!
Interesting tooth facts:
- Sharks get a new set of teeth every two weeks! They will have 40 sets in their lifetime.
- A human child will lose their first tooth around 6 or 7.
- A human baby has 20 teeth which start to grow at about 6 months old.
- The enamel on a humans tooth is the hardest thing in their body.
- 50% of people say that a smile is the first feature they notice about someone – so get flossing!