This is the best solution for long-term preservation of a tooth with deep decay or trauma (fracture or crack). It involves disinfecting the endodontum, ie the inside of the tooth (the pulp chamber and the root canals), usually under an operating microscope, and sealing it with bioceramics.
It is sometimes necessary to perform a new surgical procedure on already devitalized teeth, in cases where bacteria have persisted in the channels: it is called endodontic reprocessing.
The devitalized teeth are mostly fragile teeth, because a large part of enamel has been destroyed by decay. They will be reinforced with ceramic bonded restorations designed to last for a long period of time.