Every time we smile, frown, talk, or eat, we use our mouths and teeth. Our mouths
and teeth let us make different facial expressions, form words, eat, drink, and begin
the process of digestion.
The mouth is essential for speech. With the lips and tongue, teeth help form words
by controlling airflow out of the mouth. The tongue strikes the teeth or the roof
of the mouth as some sounds are made.
When we eat, our teeth tear, cut, and grind food in preparation for swallowing.
The tongue helps push food to the teeth, and allows us to taste the food we eat.
What Do the Parts of the Mouth Do?
The mouth is lined with moist mucous (MYOO-kus) membranes. The
membrane-covered roof of the mouth is called the palate (PAL-it):
The front part consists of a bony portion called the hard palate. The hard palate
divides the mouth and the nasal cavity above.
The fleshy rear part is called the soft palate. The soft palate forms a curtain
between the mouth and the throat, or pharynx, to the rear. When we swallow, the soft
palate closes off the nasal passages from the throat to prevent food from entering
The soft palate contains the uvula (YOO-vyoo-luh),
the dangling flesh at the back of the mouth. The tonsils are on either side of the
uvula and look like twin pillars holding up the opening to the throat, or pharynx
A bundle of muscles extends from the floor of the mouth to form the tongue.
The top of the tongue is covered with tiny bumps called papillae (puh-PIL-ee).
These contain tiny pores that are our taste buds. Four main kinds of taste buds are
found on the tongue — they sense sweet, salty, sour, and bitter tastes.
During chewing, salivary glands in the walls and floor of the
mouth secrete saliva (spit), which moistens the food and helps break
it down even more. Saliva makes it easier to chew and swallow foods (especially dry
foods), and contains enzymes that help begin the digestion of foods.
Once food is a soft, moist mass, it's pushed to the back of the mouth and the throat
to be swallowed.
How Do Teeth Do Their Job?
Each type of tooth plays a role in the chewing process:
Incisors are the squarish, sharp-edged teeth in the front of
the mouth that cut foods when we bite into them. There are four on the bottom and
four on the top.
On either side of the incisors are the sharp canines. The upper
canines are sometimes called eyeteeth or cuspids.
Behind the canines are the premolars, or bicuspids, which grind
and mash foods. There are two sets, or four premolars, in each jaw.
The molars, found behind the premolars, have points and grooves,
and allow for vigorous chewing. There are 12 molars — three sets in each jaw called
the first, second, and third molars. The third molars are the wisdom teeth.
Because they can crowd out the other teeth or cause problems like pain or infection,
a dentist might need to remove them.
Humans are diphyodont (dy-FY-uh-dant), meaning that they develop two sets of teeth.
The first set are 20 deciduous (duh-SID-you-wus) teeth that are also called the
milk, primary, temporary, or baby teeth. They begin to develop before birth and begin
to fall out when a child is around 6 years old. They're replaced by a set of 32 permanent
teeth, which are also called secondary or adult teeth.
What Are the Parts of the Teeth?
Human teeth are made up of four different types of tissue: pulp, dentin, enamel,
The pulp is the innermost portion of the tooth and consists of
, nerves, and blood vessels, which nourish the tooth. The pulp has two
parts — the pulp chamber, which lies in the crown, and the root canal, which is in
the root of the tooth. Blood vessels and nerves enter the root through a small hole
in its tip and extend through the canal into the pulp chamber.
Dentin surrounds the pulp. A hard yellow substance, it makes
up most of the tooth and is as hard as bone. It's the dentin that gives teeth their
Enamel, the hardest tissue in the body, covers the dentin and
forms the outermost layer of the crown. It lets teeth withstand the pressure of chewing
and protects them from harmful
and changes in temperature from hot and cold foods.
A layer of cementum covers the outside of the root, under the
gum line, and holds the tooth in place within the jawbone. Cementum is also as hard
How Can I Help Keep My Child's Mouth and Teeth Healthy?
To help keep your child's mouth and teeth healthy:
Offer a nutritious diet. Limit juice, sugary snacks, and sticky foods like dried
Help younger kids brush their teeth twice a day for 2 minutes at a time. Help
your child start to floss once a day when the teeth touch each other.
Have your child use a mouthguard during sports where there is a risk of mouth
Teach your child to never walk or run with anything in the mouth, such as a toothbrush
Make your home and car smoke-free. Children exposed to secondhand
smoke are more likely to get cavities. If you or anyone in your household smokes,
call 1-800-QUIT-NOW for tips and advice on quitting.
Talk to the doctor or dentist if your child is still using a pacifier or sucking
the thumb by the age of 4 years. They can give you tips to help you break your child
of the habit, and see if it's affecting the way the teeth line up.