Root canal therapy- refers to the process by which a dentist treats the inner aspects of a tooth, specifically that area inside a tooth that is occupied by its "pulp tissue." Most people would probably refer to a tooth's pulp tissue as its "nerve." Endodontic therapy involves the removal of these structures, the subsequent cleaning, shaping, and decontamination of the hollows with tiny files and irrigating solutions, and the obturation (filling). Injuries to the dental pulp tend to be from decay which becomes so deep in the tooth structure that it actually touches the nerve. Inflammation of the nerve can also be caused by trauma.