A root canal may or may not begin with pain. Many times a root canal is the result of throbbing pain, pain that is onset when chewing or biting, a high sensitivity to heat and cold, and a fever to list only some of the symptoms. Sometimes the dentist will see signs of infection before the pain begins.
When the pulp chambers of a tooth become infected it can be very painful. The blood vessels, nerves and connective tissue that help a tooth grow during development can develop an infection. This can be called an abscessed tooth and many have described the pain to be very strong.
A root canal begins with a small hole in the top of the tooth to allow access to the infection. The infection will be removed through this hole. Once the infection is cleared the pulp chamber will be filled with gutta-percha which is a rubber-like material used to seal the small access hole. The tooth will then be cleaned and sealed.
One this procedure is complete there will need to be a restoration placed on the tooth to permanently protect the tooth from any further damage. We would recommend a dental crown for the long term.