Where There Is No Dentist 2012 41
What Holds the Teeth?
THE IDEA:
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.
root
The roots of the tooth
do not actually touch
the bone. Root fibers
connect the root and
bone, holding the
tooth in place.
root
fibers
bone
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.
ACTIVITIES:
1. 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.