What makes teeth so hard?
The hardest part of the tooth is the outer covering called enamel. It is made mostly of a chemical called calcium phosphate. This is different from the chemical that makes up seashells, which is calcium carbonate. Luckily, sea shells and teeth don’t dissolve in water.
What's the dentist's blue light for?
There is a special soft flexible plastic material that is used to fill a tooth that has a cavity. Once the plastic is in the cavity, the dentist shines a blue light on the plastic which makes it very hard. The special blue light is not ultra violet and is not a laser. It is a certain color of blue and intense enough to cause a chemical reaction in the soft plastic to make it really hard.
What is fluoride and why is it in toothpaste?
There are bacteria in your mouth and on your teeth. These bacteria produce acid that can react with your tooth enamel and wear it away. Fluoride connects with the calcium in your enamel to make it more difficult for acids to damage it.