Encompasses the study and practice of the basic and clinical sciences involving the biology of the normal dental pulp. It also includes the diagnosis, prevention and treatment of diseases and injuries of the dental pulp along with associated periradicular conditions. It involves either preserving part, or all of the dental pulp in health, or removing all of the pulp in irreversible disease. This includes teeth with irreversible inflamed and infected pulpal tissue. The main purpose of endodontic treatment is to remove the pathological pulp, then clean and shape the root canal system, disinfect the contaminated root canals, and then obturate (fill) the root canal system to prevent re-infection and promote periradicular healing.