Why are root canals necessary?
Tooth Decay
The most common cause of root decay is the uncontrolled process of tooth decay. When tooth decay begins, it penetrates the outlayer of enamel and creates a cavity. If that process is not stopped, the decay will continue toward the nerve of the tooth.
Infections
Sometimes a tooth will become infected from within causing an abscess that can be terribly painful. An infected tooth can swell, be tender or cause pain when chewing. Infection can also affect the underlying bone which may have to be treated with antibiotics before the root canal therapy can proceed.
Trauma
Sometimes trauma or injury to the tooth will injure the nerve. Injury to teeth is common from automobile accidents, blows to the mouth, collisions during sports, and teeth can crack or break spontaneously while eating.