Learn about the four types of teeth and the journey food takes through the digestive system.
Digestion is the process by which our bodies break food down into nutrients small enough to be absorbed into the blood and used for energy, growth and repair. It begins in the mouth, where teeth mechanically break food apart and saliva starts to chemically break it down. Humans have four types of teeth, each with a different job: incisors (the flat front teeth) cut food, canines (the pointed teeth) tear it, and premolars and molars (the flat back teeth) grind it. We have two sets of teeth — 20 milk teeth that fall out in childhood and up to 32 permanent adult teeth. After the mouth, food travels down the oesophagus to the stomach, where acids continue breaking it down. Nutrients are absorbed in the small intestine, and water is absorbed in the large intestine. What remains passes out of the body as waste. Brushing teeth twice daily helps prevent tooth decay caused by acids from bacteria feeding on sugar.
