Hesperian Health Guides
What holds the teeth?
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When you look inside someone's mouth, you see only the top part of each tooth. The bottom part, its root, is inside the bone under the gum.
|The roots of the tooth hold it in the bone just like the roots of a tree hold it firmly in the ground.||The roots of the tooth do not actually touch the bone. Root fibers connect the root and bone, holding the tooth in place.|
The gums do not hold the teeth, but healthy gums will keep harmful germs from getting to the bone and root fibers. When the gums are not healthy, they form deep ‘pockets’ which collect germs. Soon, these germs will reach the root fibers and bone. The bone pulls away from the tooth in order to get away from the germs. With no bone to hold it, the tooth is lost. This is the most common reason why teeth fall out.
Have the students look for an old jaw bone from a dog or other animal. Notice that bone goes around every root of every tooth and holds it tightly. Break away some of the bone and look at the roots of the teeth.
Front teeth need only one root because they are used for biting.
Back teeth have 2, 3, or even 4 roots. That makes them strong enough to chew tough meat and even break hard bone.
Show your students how infected gums can cause teeth to fall out.
A B Ctop of
A. When gum disease is beginning, a small red `pocket’ forms where the tooth meets the gum. Germs and food collect in the gum and make acid. This makes the gums sore. B. As a result, the gum pulls away and the pocket becomes deeper. C. The bone moves away from the infection and no longer holds the tooth.
Try to think of other ways to teach how gum disease pushes the bone away from the tooth. In Jamaica, dental workers ask, “What do you do if someone attacks you with a machete (long knife)?” “I run away!” most people answer. “Exactly,” say the dental workers, “and when you have a lot of germs attacking the root of your tooth, the bone ‘runs away’ and leaves the tooth with nothing to hold it.”
Tell a story to show how, when the gum moves away from the top of the tooth, the root and bone are open to attack. For example:
One day, a hen was sitting on the eggs in her nest. The hen was hungry, and when she saw a worm, she left the nest to catch the worm. Just then, a possum came along, saw the fresh, warm eggs, and ate them all up.
Explain to the students that the gums protect the teeth the way a hen protects her eggs. When she leaves the eggs unprotected and exposed, an animal can attack and destroy them. When gums around a tooth are red and sore, the tooth is exposed to germs that can attack not only the top of the tooth, but also the bone and root.