The nerve chamber for teeth sits deep in the center of the tooth. Your enamel and dentin protect it from the bacteria that normally live in your mouth. If those bacteria get into the nerve chamber, it will set up an inflammatory reaction within the nerve chamber. As this chamber is enclosed within a hard substance, the roots of your teeth, the cells that enter the tooth from the inflammatory reaction can actually suffocate the healthy cells of the tooth causing nerve death. It is important to protect the nerve of the tooth by filling any holes in your teeth as soon as possible. Fills also help to restore the tooth to its natural shape and function.