Teeth


Tooth Facts

Teeth [tēth]

Hard white objects inside the mouth that are used for biting and chewing.

Smile! Show off those teeth. Strong teeth are a sign of good overall physical health. Without them, you can't eat or even speak well. Your teeth are important.

What Is a Tooth?

Teeth are like bones. They are alive. They start forming before you are born and continue to develop until you are an adult. Teeth form inside the jaw and are nourished and protected by the pink tissue that surrounds them. That pink tissue is called the gums. The crown is the part of the tooth you can see above the gums, but there is a lot more to your teeth.

The tooth is made up of five parts. The enamel is the white covering on the top. It is the hardest substance in your whole body. The layer under the enamel that you can't see is the dentin. It makes up most of the tooth and isn't as hard as the enamel. The pulp is under the dentin and it is the softest part of the tooth. It is made up of nerves and blood vessels. It is what hurts when you get a toothache. The root is what holds the tooth in place and a thin layer of tissue called the clementum protects it.

How Many Teeth?

Kids have about 20 teeth by the time they turn 3 years old. This first set of teeth are called milk teeth, baby teeth or primary teeth. By the time you are five or six, your first permanent teeth will start coming in. The permanent teeth lie just beneath the roots of the baby teeth.

As a permanent tooth grows, it puts pressure on the baby teeth. That pressure causes the root of a baby tooth to dissolve and the baby tooth falls out. The permanent tooth then moves into place. By the time you are an adult, you should have 32 teeth.

Mammal Teeth

Mammal teeth are called heterodonts, meaning they have two types of teeth — the primary teeth and the permanent teeth. Mammals have four types of teeth, each with a specific task to handle for different kinds of food. Incisors are used for cutting. Canines are for tearing. Premolars are used for crushing, and molars are used to grind up food. Not all mammals have all, or even any, of each kind of tooth. It all depends upon what kind of food the animal eats.

Humans have:

  • Eight incisors — four in your upper jaw and four in your lower jaw in the front of your mouth. Incisor means “biting tooth” and these teeth help you bite into your food.
  • Four canines — two in your upper jaw and two in the lower jaw. Your canines are located next to the incisors. Canine means “like a dog.” These teeth are pointed and are used to stab and tear at food.
  • Eight molars — four in your upper jaw and four in your lower jaw. These teeth in the back of your mouth help you grind your food.

Different Kinds of Animals Have Different Types of Teeth

Carnivores need long canine teeth so they can grip and kill prey quickly. Their incisors strip flesh from bones. They don't need molars for grinding food. They have teeth that slice meat — these are called carnassial teeth, not molars.

Herbivores do not have upper incisors because they cut the plants with their lips instead. All herbivores need their molars (the big flat teeth at the back of the mouth) for grinding the mouthfuls of food. A herbivore's molars are big and ridged for better grinding.

Omnivores have teeth that are used for many different things. Like grasping, cutting, grinding, and slicing. This is especially true for humans. Yes, humans are omnivores, meaning they eat meat, fruits and veggies!

Insectivores have teeth that are square with sharp points that are perfect for tearing up insect bodies.

Taking Care of Your Teeth

Ancient Egyptians believed that a mixture of onions, spices and incense would cure a toothache. Today, we know that toothaches happen when you don't take care of your teeth.

When you eat, bits of food particles are left on your teeth. When sugars combine with bacteria in your mouth, plaque forms. The plaque forms acids that can eat a hole in the tooth. This is called a cavity.

Left untreated, the cavity can spread into the dentin and then into the pulp. If bacteria gets into the pulp, it can cause the blood vessels to swell and press on the nearby nerves. Ouch! Now you have a real toothache. Do animals get cavities? You bet! Especially if they don't take care of their teeth. Even animals get cavities! Check out the bear's filling!

Plaque can also harden into a chalky substance called tartar. Tarter can cause gum disease. If your gums aren't healthy, they can't protect your teeth. If the gum disease gets really bad, you can lose a tooth. And gum disease can also lead to other health problems like heart disease and strokes. So taking care of your teeth is important for your whole body!

Keeping Your Teeth Healthy

You can prevent cavities and gum disease by brushing at least twice a day. You should use a fluoride toothpaste and a toothbrush with soft, rounded bristles. Brush with short, angled strokes.

Brush the front and back sides of your teeth and don't forget to brush your tongue too! That will help keep your breath fresh. When brushing, you should brush for 2 minutes on your upper teeth and 2 minutes for your bottom teeth. You should brush in the morning, the evening, and after eating meals! Be sure to rinse your brush well and get a new brush every three months.

No time to brush after a meal? Be sure to rinse your mouth out well with water to help clean away as many food particles as possible until you can get to your toothbrush! Besides, germs love a dry mouth. So, if you drink lots of water to help wash away leftover foods, there will be fewer places for bacteria to grow!

Besides brushing, you should also floss once a day. Flossing removes food and plaque from between your teeth — places your toothbrush cannot reach. This is also a great way to help prevent gum disease.

You should also make regular visits to your dentist and eat right. Candy and other sticky, sugary foods are bad for your teeth. Eating a good healthy diet, brushing and flossing often, and visiting your dentist regularly are the best way to keep a healthy smile!

Going to the Dentist

Even if you don't have a toothache, you should visit your dentist at least twice a year to check your teeth. When you visit the dentist she will examine your teeth and gums, and either the dentist or the dental hygienist will clean your teeth to remove the plaque and tartar from your teeth.

Dentists and hygienists use special tools to clean and check your teeth. The dentist will use an explorer to check and clean around your teeth. It is a metal tool with a hook on the end. Dentists also use a small suction tube to suck the water and saliva out of your mouth. The dentist will also use a mirror to help get a better look at all the surfaces of your teeth. If the dentist finds any cavities they will take an X-ray of your teeth, remove the decayed part of the tooth and put in a filling to prevent further decay. Piece of cake! Well, maybe that's not the best choice of words . . . but going to the dentist is pretty painless these days!

Wild and Wacky Facts

Who has the most teeth?

  • On land the mammal with the most teeth is the Giant Armadillo, which can have as many as 100 teeth in its jaws.
  • In the oceans the real tooth master is the long-snouted spinner dolphin. They can have as many as 252 teeth in their long thin jaws. These teeth are more like reptile teeth because they are all the same basic shape, thin sharp little spears. These teeth are good for catching and holding the little fishes that dolphins eat.

Shark lose teeth throughout their life and they grow new ones to replace the lost teeth. As soon as one falls out, another one takes its place.

Poisonous snakes have specialized teeth called fangs. Fangs are hollow teeth that pierce skin and inject poison.

Rats gnaw all the time to help wear down their teeth. If they didn't wear down them down, their bottom teeth would continue to grow longer — potentially right into their brain.

Some animals dig with their teeth, while others use their teeth for self-defense or displays of power, such as when males fight for territory or for females. Wild pigs dig with their tusks, which are actually canine teeth. Even the mighty walrus will use its large canine teeth to anchor itself to ice while sleeping.

Can you believe this?

Our first president, George Washington, did not have teeth made out of wood, but he did have teeth made out if hippopotamus teeth. He also had teeth made out of ivory, lead, human teeth, and cow and sheep's teeth.

In the early 1600s, Japanese women blackened their teeth. They thought it showed loyalty to their husbands. Eww . . . yuck!

In the ninth century, Mayans filed their teeth into different shapes and decorated them with jewels. Today, some people get “grillz” to impress their friends. What do you think? Think jewelry on your teeth is cool? Maybe, but not if you wear it for an extended period of time — it can cause tooth decay and gum disease. So, if you do add some sparkle to your smile, be sure to take care of the teeth underneath so you don't lose all your shine!

Fun Links

Here are some activities to do at home to help you understand your teeth and their importance. Dentists4Kids has worksheets, puzzles, coloring sheets and more.

Explore the anatomy of teeth at Stanford Children's Health site.

Get the truth about teeth from Kids Health.

Check out this fun interactive site from Children's University.

Find coloring pages, puzzles, brushing charts, and activity sheets at the American Dental Association Kids' Page.

Students worldwide learn about teeth. Check out what a school in England have to say.

Find out more about incisors, canines, and molars at DK Find Out.

How strong are your teeth? Why don't baby teeth just grow up? Which fish has the largest teeth? Find out the answers to these questions and more at Wonderopolis.

Meet the Tooth Defenders! Join their mission to protect Tooth City from the sugary villain and his sticky schemes.

Check out what Neuroscience for Kids from University of Washington says about teeth!

Are your dog's teeth different than yours? Find out how. Investigate the world of mammals and their teeth.

Did you know that elephant tusks are very elongated incisor teeth? Learn more about some of the world's longest teeth.

Elephants aren't the only ones with tusks. Learn more about one of the most mysterious animals in nature — the Narwhal.

Check out these weird and wacky facts about teeth.

Burrow through some amazing facts on mammals and teeth.

Top 10 Questions

February 2008

Thanks to Dr. Dustin Weitz, Moscow dentist, and Dr. Stephen Bruce, Boise dentist for the answers.

  1. Why should we floss our teeth every day?

    Flossing is important for several reasons. People can get different types of problems with their teeth, and one would be cavities. You can have gum problems, and flossing will get into places where your toothbrush just can't reach. So it helps clean your teeth to help you from having problems with your gums, which are around your teeth. (From Emma in Mrs. Fryer's class at Clearwater Valley Elementary)

  2. Are teeth a bone?

    Technically they are not a bone; they are actually harder than a bone. They're made up of enamel and dentin, and inside is the pulp where the nerves and blood vessels are. Those are necessary when that tooth is growing, and that's where you have this sensation of hot and cold or pain in a tooth. (From Sydney in Mrs. Woodall's class at Hayden Meadows Elementary School)

  3. How do you lose teeth?

    When you lose one of your baby teeth what's actually happening is you'll have a permanent tooth that is growing underneath the primary tooth (the baby tooth). The loosening is a process where the root of the baby tooth actually dissolves and then it will fall out on its own. (From Savannah in Mrs. Fryer's class at Clearwater Valley Elementary School)

  4. How does plaque make your teeth yellow?

    Plaque will actually build up on the surface of your tooth and can make a tooth look yellow. After you have that brushed off or cleaned off, your tooth actually won't be yellow underneath unless that plaque has sat on there for a long time. Plaque hardens and becomes tartar. And if you have that on your tooth, you should come in to a dentist and do a really good cleaning where we can get that off so it doesn't become a major problem. There are little pits and pores and grooves in your teeth, and things that people eat can sometimes cause stain to get into those areas and darken a person's tooth. (From Seyara in Mrs. Hooper's class at Gooding Elementary School)

  5. What is a root canal?

    When people talk about root canals typically what they're talking about is when the dentist has to go inside that tooth because either that tooth broke so severely it went into the pulp, or decay went into the pulp, or sometimes teeth just die. In those situations we have to make a hole through the top of the tooth, go into it, and clean out all of that tissue out of the canals where the nerves and blood vessels are. Then we put a soft filling material in there so they can keep that tooth in the mouth even though it is technically dead. (From Hannah in Mrs. Hunt's class at Cynthia Mann Elementary)

  6. How much candy does it take to rot out your teeth?

    It depends on how well you're taking care of your teeth. If a person does eat candy that has a lot of sugar in it, and if you leave it on for a long time, then you're going to have problems with that turning into the acid that can dissolve a person's tooth. But if you brush your teeth with toothpaste very soon after you've eaten candy, the toothpaste will help clean that off and also strengthen your tooth. (From Chase in Mrs. Hooper's class at Gooding Elementary School)

  7. What in toothpaste helps your teeth?

    Well, most of all there's an abrasive in there; very, very small pumice particles. It has an abrasive quality that helps to clean off the teeth, just like an abrasive cleaner that you would use on the floor. Most toothpaste also has fluoride, and fluoride is a good thing to have on teeth, because the fluoride and the bacteria that causes tooth decay don't get along very well. (From Henry at McDonald Elementary in Moscow)

  8. What connects your teeth to your jaw?

    The tooth sits in the bone, but then the gum tissue that you see around it connects to something that they call a ligament, like little fibers that hold the tooth into your jaw. That's one of the things that as a person gets older, if they're having plaque that gets built up in between their teeth, it can actually get down into that ligament and cause a problem that they call gum disease - that's where bacteria gets in between the jaw bone and the tooth, and that's also one of the reasons we like to get in there with floss, because the floss will get to that area where your toothbrush can't reach. (From Raely in Mrs. Hooper's class at Gooding Elementary School)

  9. My dad smokes. Is smoking bad for your teeth?

    That's a great question. Smoking can be very hard on a person's teeth because it can really dry a person's mouth out - everybody has saliva in their mouth, that's what makes your teeth wet. When the mouth dries out it actually irritates your gums, so you can get cavities a lot easier when you smoke. So actually, smoking cigarettes can be pretty hard on a person's teeth. A person is also more prone to oral cancer if they're a smoker. (From William in Mrs. Olson's class at Oregon Train Elementary School in Twin Falls)

  10. What are the causes of tooth decay?

    When we eat, a lot of the foods we eat have sugars in the food. Also, everybody has bacteria in their mouth, which are like little microscopic bugs. Those bacteria take that sugar and use it for food like we do our regular food, but when they break it down that actually makes acids. Acids dissolve the minerals out of your teeth, and that's what causes the cavity. (From Ryana in Mr. Franklin's class at Meridian Elementary School)