Human beings grow two sets of teeth. The first is the milk or temporary teeth (during childhood) These are 24 in number. They loosen and fall out. They are replaced by the permanent teeth (in adulthood). The permanent teeth are usually 32 in number.
Structure of the Teeth
- The crown: the part of the tooth projecting above the gum
- The root: the part buried in the jaw-bone
- The neck: the space between the crown and the root
- The dentine: the tough centre of the tooth which surrounds and protects the pulp cavity
- The pulp cavity: contains blood vessels and nerves
- The enamel: a very hard substance which covers the crown of the teeth.
TYPES OF TEETH AND THEIR FUNCTIONS
- The incisors; these are in the center of the front of the jaw. They are used for cutting off lumps of food. They are usually eight in number.
- The canine; these are beside the incisors. They are pointed and used for tearing food. They are sometimes called ‘dog’ They are usually four in number.
- Premolars; these are next to the canine. Each has one or more points for cutting. They may also have flat surfaces for grinding food. They are usually eight in number.
- Molars; these are behind the premolars. They are similar to the premolars. They are however only present in permanent dentition, children do not therefore have molars. They are usually twelve in number.
DAILY CARE OF THE TEETH
- Clean your teeth every morning and at bed time with either a clean chewing stick or tooth brush with paste.
- Avoid using your teeth as nut-crackers or opener for soft drinks and beer bottles.
- Eat balanced diets for strong healthy teeth. Some important foods are milk, fruit, fish, meat and other sources of calcium.
- Avoid extremely hot and cold food. These may crack the enamel leading to tooth decay.
- Do not eat sweets or highly sweet foods which may cause tooth or dental decay.
- Exercise your teeth by eating fairly hard foods like maize, carrots, coconuts. e.t.c.
THE HANDS AND THE FEET
The hands, fingers, nails and feet are very important parts of the body. We even put them into our mouths. The legs are in close contact with the ground, dust and dirt. They can also become hiding places for disease and germs. The hands and the feet are parts of the upper and lower limbs. The hand starts from the wrist. It is made up of the palm, the fingers and the nails. The first finger is called thumb. The leg starts from the ankle and consists of the heel, sole, toes and nails.
Functions Of Hands And Feet
- The hands and fingers are used for touching things.
- They are also used for doing different types of work
- The legs give us support
- The legs are used for walking about
- The legs also perform many other useful activities, such as playing games, dancing, e.t.c.
Care Of The Hands
- Wash the hands after using the toilet and after each meal.
- Always wash the hands with mild soap
- Always scrub around and under the finger nail using face towel or soft sponge
- Rinse the hand with clean water
- Dry properly with clean cloth
- Apply a little hand lotion or cream to keep the hand soft
- Keep the finger nails well-trimmed and clean.
Care Of The Feet
- Wash the feet thoroughly and as often as possible and then dry them carefully. Always pay enough attention to the part between the toes.
- Remove any rough dry skin around the sole of the feet by rubbing with a pumice stone.
- Rinse properly and dry with a clean towel.
- Apply a coating of cream, lotion or petroleum jelly on the feet after washing to prevent dryness.
- Keep the toe nails short and clean so that they do not harbor germs.
- Avoid the habit of walking bare-footed especially on unpaved ground.
- Wear good-fitting and comfortable shoes.
Note: Manicuring: is the process of caring for the hand and finger nails while
Pedicure: this is the care for the feet and the toe nails
- What is the dental formula for man
- Differentiate between manicure and pedicure
- Mention three materials used for the production of foot wears
Draw and label the structure of a tooth.