A root canal is required when a tooth is decaying internally into the pulp chamber causing infection. It requires the dentist to drill into the tooth, extract the pulp (nerve) prior to filling the canals and crowning the tooth to prevent future decay.
Root canal treatment is achieved over a minimum of 3 appointments usually 2-4 weeks apart.
The pain from root canal injury will not heal by itself. If left unattended it will deteriorate, causing worse pain as it progresses. The infection will spread, bone around the tooth will begin to degenerate and the tooth may fall out.