Pain is not the reason you are having a root canal, but it is a great motivating factor! The reasons for having a root canal would be:
1. A cavity that has reached the center or nerve of the tooth. Once bacteria reach the nerve of the tooth, the nerve will become infected, secondarily inflamed, and need to be removed.
2. The tooth has been traumatized. When a tooth is traumatized, the blood flow to the tooth is compromised. The tooth may darken over time. Also under trauma comes other categories; a filling, a few fillings, a crown (cap) preparation, braces, periodontal work, a crack, grinding or clinching of your teeth. All can be cumulative effects to a nerve dying in the tooth.
3. The general dentist may need the root canal done to complete further work on the tooth. There may not be enough tooth structure to place a proper crown (cap) on the tooth. The tooth has to be built up. The surface area in the root will be used to cement a post. Not enough tooth structure means a cap that repeatedly comes off
Teeth may have one or several roots. The center of each root is hollow. The center would be the canal that contains the pulp. The pulp is made up of the nerve and blood vessel. Once bacteria reach the nerve canal from a cavity, the nerve will start to become infected, inflamed and die. The bacteria are free to live in the tooth, multiply, and spread out into the jaw bone through the opening in the end of the root.
The Endodontist will clean and sterilize the canals. The infected nerve tissue and bacteria are removed. The canal is sterilized. The sterilized and empty canal will be filled with a biocompatible material, a rubber-like material called ‘gutta-percha.”
Once bacteria are living in the tooth, the inflammation destroys the blood vessel in the tooth. Neither your body nor any antibiotics can get into the tooth to defeat the bacteria. The antibiotics can appease the infection in the bone, alleviating some pain, but cannot cure the problem in the tooth. Once we have sterilized the inside, the gutta-percha seals it off like a cork in a bottle.
The gutta-percha has three dimensions just like the cork. It has to fill up the whole nerve canal to the end of the root.