Page 28 - Viva ICSE Science 4 : E-book

TIME TO REVISE

Match the following.
Column A Column B

1. Deciduous teeth (a) sharp and pointed teeth
2. Permanent teeth (b) fl at and broad teeth, located next to
canines
3. Incisors (c) bigger, wider and have ridges; 6 in
each jaw

4. Canines (d) fl at teeth with sharp edges at the
front of mouth
5. Premolars (e) 20 in number

6. Molars (f) 32 in number

A Tooth and its Parts

All types of teeth have a basic structure.
enamel
Generally, a tooth has two parts, i.e., a crown

and a root. crown dentine

The crown is the visible part of a tooth. The root
gums
is the part of the tooth present inside the gums.
Gums are the soft tissue that surround the teeth
pulp
and hold them fi rmly in their place.
root
A tooth is made up of three main layers. They are blood
enamel, dentine and pulp. vessel

• Enamel is the outermost layer that covers nerve
the crown part of the tooth. It is generally Parts of a tooth

white and shiny. It is harder than bone and
protects the tooth from decay. It is made up of minerals like
calcium and phosphorus. Did You Know!

• Dentine is the hard yellow substance that lies under the Enamel is the
hardest substance
enamel. It is the sensitive part of tooth.
of our body.
• Pulp is the central soft part of the tooth. It contains blood

vessels and nerves that supply nutrients to the tooth and
nourishes it.

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