Teeth

• Root: part of the tooth which is embedded in the gum.
• Crown: part of the tooth which can be seen.
• Enamel: covers the crown. The hardest substance made by animals. However, it can be dissolved by acids made by bacteria.
• Dentine: a layer under the enamel. It is also quite hard and contains living cytoplasm.
• Pulp Cavity: it is at the middle of the tooth. It contains nerve and blood vessels. These supply the cytoplasm in dentine with food and oxygen. 
• Cement: covers the root of the tooth. This has fibres that attaches it to the jawbone. 
• INCISORS: sharp-edged, chisel-shaped teeth at the front of the mouth.
• INCISORS are for biting off pieces of food.
• CANINES: more pointed teeth at either side of the incisors.
• CANINES are for gripping food.
• PREMOLARS and MOLARS: the large teeth towards the back of the mouth.
• PREMOLARS and MOLARS are used for chewing food, crushing it into smaller pieces to help with mechanical digestion. 
• TOOTH DECAY: caused by bacteria. Some of the bacteria, together with substances from your saliva, form PLAQUE.
• PLAQUE: a sticky film over your teeth, especially next to the gums and in between the teeth. Created from bacteria and substances in your saliva.
• Bacteria in plaque will feed on sugar left on the teeth, using it in respiration.

  Acid will be created, damaging the tooth.
• The acid created by the bacteria in plaque gradually dissolves the enamel covering the tooth and works its way into the dentine. 
• 1. Particles of sugary foods get trapped in cracks in the teeth.
  2. Bacteria feeding on the sugar form acids, which dissolve a hole in the enamel and dentine.
  3. There are nerves in the cavity, so the tooth becomes very painful. 
• TO KEEP THE TEETH HEALTHY:

  1. Don’t eat too much sugar.
  2. Use fluoride toothpaste regularly.
  3. Do regular and thorough brushing.
  4. Make regular visits to the dentist.