Plaque, Sugar and Acid

In the picture

1. 1Sticky film on the tooth: a clear layer packed with rod-shaped bacteria
2. 2Sugar crumbs: sweet food bits resting on the film
3. 3Acid droplets: tiny wet spots the bacteria make from the sugar
4. 4Softened enamel: a chalky patch where the acid eats into the white surface

Examples

• Sipping a sweet drink slowly leaves sugar sitting on the teeth for a long time.
• Forgetting to brush at night lets the film and acid keep working while you sleep.

Quiz: Plaque, Sugar and Acid (Age 11)

1. 1

   What do the bacteria in the sticky film do to sugar?

   • They use it to repair the enamel.
   • They turn it into a hard white coating.
   • They turn it into acid.
2. 2

   What does acid do to tooth enamel?

   • It pulls minerals out, and enamel does not grow back.
   • It only changes the colour and leaves enamel hard.
   • It adds minerals, making enamel stronger.
3. 3

   Where does the acid on teeth come from?

   • Gums make it from food left between teeth.
   • Bacteria in the sticky film make it from sugar.
   • Teeth make it from calcium in saliva.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.