HARMFUL EFFECTS OF MICROORGANISMS
1. Microorganisms cause diseases called pathogen.
Example: tooth decay, food poisoning and diseases
are all caused by microorganisms.
Tooth decay (Caries)
1.Tooth decay caused by bacteria.
2.After eating, layer of plaque is formed on the suface of teeth.
Plaque = saliva + food residue + bacteria
3. Bacteria act on the food residue, produce lactic acid.
4. Lactic acid corrodes the enamel and the dentin.
When damage reaches the pulp (nerves and blood vessels)
toothache is felt.
5. Caries can be prevented by:
a. Brushing and flossing after meals
b. Avoiding sweet food
c. Adding fluoride to tap water
d. Regular dental check-ups
