You bite into an apple and then try to start talking to your friend about yesterday's
math homework. Suddenly something feels funny — one of your baby teeth has fallen
out! It's been loose forever, and now there it is, right in your hand. And you have
an empty space in your mouth big enough to poke a drinking straw through.
Before you put that tooth under your pillow, did you know that there is much more
to that tooth than meets the eye? A single tooth has many different parts that make
it work. And teeth play an important role in your daily life. They not only let you
eat stuff like apples, they also help you talk. So let's talk teeth!
Unlike your heart or brain, your teeth weren't ready to work from the day you were
born. Although babies have the beginnings of their first teeth even before they are
born, teeth don't become visible until babies are about 6 to 12 months old.
After that first tooth breaks through, more and more teeth begin to appear. Most
kids have their first set of teeth by the time they are 3 years old. These are called
the primary teeth, baby teeth, or milk teeth and there are 20 in all. When a
child gets to age 5 or 6, these teeth start falling out, one by one.
A primary tooth falls out because it is being pushed out of the way by the permanent
tooth that is behind it. Slowly, the permanent teeth grow in and take the place of
the primary teeth. By about age 12 or 13, most kids have lost all of their baby teeth
and have a full set of permanent teeth.
There are 32 permanent teeth in all — 12 more than the original set of baby
teeth. Most people have four teeth (called wisdom teeth) grow in at the back of the
mouth when they're between 17 and 25 years old. These complete the adult set of 32
Let's take a tour of your teeth. Look in the mirror at your own teeth or check
out a friend's smile. The part of the tooth you can see, which is not covered by the
gum (your gums are the pink, fleshy part), is called the crown. The
crown of each tooth is covered with enamel (say: ih-NAM-ul), which
is very hard and often shiny. Enamel is a very tough substance and it acts as a tooth's
personal bodyguard. Enamel works as a barrier, protecting the inside parts of the
If you were able to peel away the enamel, you would find
dentin (say: DEN-tin). Dentin makes up the largest part of the tooth.
Although it is not as tough as enamel, it is also very hard.
Dentin protects the innermost part of the tooth, called the pulp.
The pulp is where each tooth's nerve endings and blood supply are found. When you
eat hot soup, bite into a super-cold scoop of ice cream, fall and hurt a tooth, or
get a cavity, it's your pulp that hurts. The nerve endings inside the pulp send messages
to the brain about what's going on ("That ice cream is too
cold!"). The pulp also contains the tooth's blood vessels, which feed the tooth and
keep it alive and healthy.
The pulp goes all the way down into the root of the tooth, which is under the gum.
Cementum (say: sih-MEN-tum) makes up the root of the tooth, which
is anchored to the jawbone.
You've probably noticed that you have different types of permanent teeth in your
mouth. Each one has its own function.
Your two front teeth and the teeth on either side of them are incisors
(say: in-SY-zurs). There are four on the top and four on bottom.
Incisors are shaped like tiny chisels, with flat ends that
are somewhat sharp. These teeth are used for cutting and chopping food. Think back
to that apple you ate: You used your incisors to crunch into the skin of the apple.
The pointy teeth beside your incisors are called canine (say:
KAY-nine) teeth. There are four of them, two on top and two on bottom. Because these
teeth are pointy and also sharp, they help tear food.
Next to your canine teeth are your premolars (say: PREE-mo-lurs),
which are also called bicuspid teeth. You have eight premolars in all, four on top
and four on the bottom. You'll need to open a bit wider to see these teeth, but when
you do, you'll notice that their shape is completely different from both incisors
and canines. Premolars are bigger, stronger, and have ridges, which make them perfect
for crushing and grinding food.
If you open your mouth really wide, you'll see your molars (say:
MO-lurs). You have eight of these, four on the top and four on the bottom. Sometimes
these are called your 6-year molars and your 12-year molars because that is around
the time when they come in.
Molars are the toughest of the bunch. They are even wider and stronger than premolars,
and they have more ridges. Molars work closely with your tongue to help you swallow
food. How? The tongue sweeps chewed-up food to the back of your mouth, where the molars
grind it until it's mashed up and ready to be swallowed.
As we mentioned earlier, the last teeth a person gets are wisdom teeth. These are
also called third molars. They are all the way in the back of the mouth, one in each
Wisdom teeth may have to be removed because they can cause problems in a person's
mouth. Some people believe that wisdom teeth may have been used by people millions
of years ago when humans had larger jaws and ate food that needed a lot of chewing.
It's believed that they're called wisdom teeth because they come in later in life,
when a young person is becoming older and wiser.
Your teeth are great for chewing, but you also need them to talk. Different teeth
work with your tongue and lips to help you form sounds. Try saying the word "tooth"
slowly and notice how your tongue first hits the inside of your incisors to produce
the hard "t" sound and then goes in between your upper and lower teeth to make the
And if you love to sing "la la la la la," you can thank those teeth every time
you sing a song. Pay attention to what happens to your teeth and tongue every time
you make the "l" sound.
Treating Teeth Kindly
Brushing your teeth with fluoride toothpaste is your best bet when it comes to
keeping your teeth in tip-top
shape. Try to brush after eating or at least twice a day. It's especially important
to brush before bedtime.
The best way to brush your teeth is in little circles — go around and around
until you have covered every surface of every tooth. Brush up and down, rather than
side to side. You'll also want to clean between your teeth with dental floss (a special
string for cleaning your teeth) at least once a day. That removes food and plaque
(sticky stuff that can cause cavities or gum disease) that get stuck in between your
teeth. You can also brush your tongue to help keep your breath fresh! Your dentist
may suggest that you use an alcohol-free mouth rinse.
It's also important to visit your favorite tooth experts — your dentist
and dental hygienist. During your appointment, they'll look out for any problems and
clean and polish your teeth. Sometimes the dentist will take X-rays to get a better
picture of what is going on in your mouth. You also might get a fluoride
treatment while you're there.
In between dentist visits, you can prevent problems by eating fewer sugary snacks
and sugary drinks, such as soda. Sugar can hurt your teeth and cause tooth decay,
or cavities. But if you take
care of your teeth now, you'll be chewing like a champ for the rest of your life!