Teeth have multiple components to them. There is an outer enamel layer, an inner dentin layer and a nerve that runs through the very center of the tooth.
How Are Cavities Formed
A cavity forms when acid from the bacteria in your mouth eat away at the enamel and dentin layers of the tooth. The acid makes a hole in the tooth by eating away tooth structure (enamel and dentin), which allows bacteria to get inside. If a cavity gets too big, it can travel beyond the enamel and dentin layers and start eating away at the nerve of the tooth. Cavities that have reached the nerve of the tooth can be responsible for shooting, throbbing dental pain that keeps you up at night. Read more