Learning Objectives
Let Us Begin!

Have you ever wondered what happens to the roti or rice you eat? Your body has a wonderful system that breaks food into tiny pieces so your body can use it for energy and growth. This process is called digestion.

It all starts in your mouth, where your teeth do the important job of cutting, tearing, and grinding food. Let us learn about our teeth and the amazing journey food takes inside our body!

The Four Types of Teeth

Look in a mirror and open your mouth wide. You will see that not all your teeth look the same. We have four types of teeth, and each type has a special job.

Type of ToothWhere in the MouthShapeFunction
Incisors (8)Front of the mouthFlat and sharp like a bladeCutting and biting food (like biting into an apple)
Canines (4)Next to the incisorsPointed and sharpTearing food (like tearing a piece of chapati)
Premolars (8)Behind the caninesFlat top with ridgesCrushing and grinding food
Molars (12)Back of the mouthLarge and broad with ridgesHeavy grinding of food into a soft paste

Think about it: When you eat a guava, which teeth do you use first to bite into it? Which teeth chew it into small pieces?

Milk Teeth and Permanent Teeth

The first set of teeth that grow in a baby are called milk teeth (or temporary teeth). A child has 20 milk teeth. These teeth start falling out around age 6 and are replaced by a new set called permanent teeth.

An adult has 32 permanent teeth. These teeth do not grow back if they fall out, so we must take very good care of them.

FeatureMilk TeethPermanent Teeth
Number2032
When they appear6 months to 2 years of ageAround 6 years onwards
SizeSmallerBigger and stronger
Do they grow back?Yes, replaced by permanent teethNo, they do not grow back

Think about it: Have any of your milk teeth fallen out yet? How many permanent teeth do you have now?

Taking Care of Our Teeth
The Journey of Food -- The Digestive System

When you eat food, it travels through a long path inside your body. Each part of this path does a special job.

OrganWhat Happens Here
MouthTeeth chew and break food into small pieces. Saliva (spit) mixes with food and makes it soft and wet.
Food Pipe (Oesophagus)The soft food slides down this tube from the mouth to the stomach.
StomachThe stomach churns the food and mixes it with digestive juices. Food becomes a thick paste.
Small IntestineUseful nutrients from the food are absorbed into the blood here. This is the longest part of the digestive system.
Large IntestineWater is absorbed from the leftover food. The remaining waste becomes solid.

The waste that the body does not need is passed out of the body as stool. This is why eating fibre-rich foods like fruits, vegetables, and whole grains is important -- they help the waste move smoothly.

Think about it: Why do elders say "chew your food properly"? Because well-chewed food is easier for the stomach to digest!

Key Words and Meanings
WordMeaning
DigestionThe process of breaking down food into nutrients the body can use
IncisorsFront teeth used for cutting and biting
CaninesPointed teeth used for tearing food
PremolarsTeeth behind canines used for crushing food
MolarsLarge back teeth used for grinding food
Milk teethThe first set of 20 teeth in children
Permanent teethThe second set of 32 teeth that last a lifetime
SalivaThe watery liquid in the mouth that helps soften food
OesophagusThe food pipe that carries food from the mouth to the stomach
Tooth decayDamage to a tooth caused by germs and sugar (cavity)
Examples from Daily Life
Example 1: Eating an Apple

When Ravi bites into an apple, his incisors cut a piece. Then his premolars and molars grind it into a soft mush. Saliva mixes with the apple, and he swallows it. The food travels down the food pipe to the stomach.

Example 2: Meera Visits the Dentist

Meera had a toothache because she ate too many sweets without brushing properly. The dentist found a cavity in her molar. He cleaned it and filled it. Now Meera brushes twice a day and rinses her mouth after eating.

Example 3: Losing a Milk Tooth

Arjun is 9 years old. His front milk tooth became loose and fell out. His grandmother told him not to worry -- a new permanent tooth will grow in its place. Arjun now has a mix of milk teeth and permanent teeth.

Key Points to Remember
Practice Questions

A. Fill in the Blanks

  1. The four types of teeth are incisors, canines, premolars, and .
  2. Children have milk teeth.
  3. Adults have permanent teeth.
  4. The is the food pipe that carries food to the stomach.
  5. Useful nutrients are absorbed in the .

B. Multiple Choice Questions

  1. Which teeth are used for tearing food?
    (a) Incisors(b) Canines(c) Molars(d) Premolars
  2. Where does digestion begin?
    (a) Stomach(b) Small intestine(c) Mouth(d) Large intestine
  3. What causes tooth decay?
    (a) Drinking water(b) Eating vegetables(c) Eating too many sweets(d) Brushing teeth
  4. How many incisors does a person have?
    (a) 4(b) 8(c) 12(d) 20

C. Short Answer Questions

  1. Name the four types of teeth and write the function of each.
  2. What is the difference between milk teeth and permanent teeth?
  3. Describe the journey of food from the mouth to the large intestine.
Think and Do -- Fun Activity: Tooth Count

Use a mirror and count your teeth. Fill in the table below.

Type of ToothUpper Jaw (count)Lower Jaw (count)Total
Incisors
Canines
Premolars
Molars

My total number of teeth right now: __________

Have any of your milk teeth fallen out? Which ones? ____________________________