Go together. Pulpectomy is part of the root canal process, but sometimes only a pulpectomy is done for pain control reasons in prep for a root canal that is done later. Root canal therapy refers more to the completion of the process.
Pulpec. is for kids. Generally a pulpectomy is for a baby tooth and a full on root canal is for an adult. The depth of nerve removal is the main difference between the two. A pulpectomy is just the nerve tissue at the top of the nerve, while the root canal treatment goes all the way to the tip of the root.
Pulpectomy . A root canal involves removal of the pulp tissue from the tooth as well as the cleaning and shaping of the roots so that the roots can be filled and sealed. A pulpectomy involves only the immediate removal of pulp tissue for pain control in an emergency. Patients must return to have the root canal completed or risk an infection.