What happens inside the tooth
At the centre of a tooth is a chamber holding the pulp — a bundle of nerves and blood vessels that gives the tooth sensation and nourishment. When decay reaches it, bacteria get inside and pulpitis begins: the severe, often night-time pain that wakes people up.
There is an important point few people know: if the pain stops by itself after a few days, that is almost never recovery. It means the nerve has died. Bacteria keep multiplying in the dead tissue and gradually escape through the root tip into the bone. There periodontitis develops — a focus of infection, and later a cyst.
The logic of treatment is simple: remove the infected tissue, disinfect the canals and seal them so bacteria cannot get back in. The tooth then stays where it is and serves for years.