I'm interested to know what happens when you get a cavity?

Hole: A hole in a tooth. Bacteria take sugars, convert them into acids, and the acids etch the calcium out of the tooth's enamel. This allows other bacteria to penetrate into the softer dentin, and eventually into the pulp (nerve) of the tooth, creating an abscess. As the nerve endings in the pulp chamber are attacked they send a pain signal. The infection can then spread throughout your body.