Abstract: Method and apparatus for use in endodontic treatment include providing a one-way valve in the root canal system of a tooth undergoing endodontic therapy by which pressure which may build-up in the root canal system due to the production of purulence or gases from necrosing and/or infected tissue is vented from the root canal system and by which unobstructed drainage of the tooth is permitted, while at the same time food debris and foreign matter are prevented from entering and/or becoming packed within the root canal system thereby eliminating the possibility of the canal system becoming plugged and/or reducing introduction of bacteria into the root canal system. A method is disclosed for fitting a tooth with a one-way valve in a simple yet stable manner.