You call it a cavity. Your dentist calls it tooth decay or dental caries. They're all names for a hole in your tooth. The cause of tooth decay is plaque, a sticky substance in your mouth made up mostly of germs. Tooth decay starts in the outer layer, called the enamel. Without a filling, the decay can get deep into the tooth and its nerves and cause a toothache or abscess.

To help prevent cavities

• Brush your teeth every day with a fluoride toothpaste
• Clean between your teeth every day with floss or another type of between-the-teeth cleaner
• Snack smart - limit sugary snacks
• See your dentist or oral health professional regularly