With the term endodontics means that branch of dentistry that is concerned with the therapy endodontium, ie the space inside of the dental element, which contains the dental pulp (made up of cells, such as odontoblasts and stellate cells, by vessels and nerves).

It makes use of the endodontic therapy if a lesion (caries, trauma) results in an irreversible alteration of the pulp tissue, to necrosis itself. You can also use this method if the dental element to be involved in prosthetic rehabilitation that, due to the considerable reduction of dental tissue itself, would result in irreversible alteration pulp (pulp necrosis iatrogenic causes).

The orthograde endodontic therapy consists of several phases:

access to the pulp chamber
shaping with manual endodontic instruments (k-files, headstrom, Reamers etc.) or mechanical (steel instruments such as drills Gates, Large, or nickel-titanium as M2, Pro-files, Pro Taper etc.).
cleansing of the root canal using different irrigants (hydrogen peroxide, sodium hypochlorite, calcium chelators).
sealing of all three-dimensional structures of the channel (including lateral canals and apical delta) via a thermoplastic rubber (Guttapercha) according to the techniques of lateral condensation cold, hot and vertical condensation.

The endodontist

The endodontist is a dentist or dentist that deals mainly or exclusively of endodontics, its therapeutic actions are inherent in the dental pulp or endodontium.

The main changes concern the root canal treatment for teeth with necrotic pulp or gangrene, root canals of teeth compromised by deep caries or trauma, pulpotomie, apicificazioni, pulp capping pulp and interventions of surgical endodontics: the latter has as its objective the treatment of diseases of the periapice as granulomas and abscesses periapical through the creation of a flap surgery, therapy of the lesion and the subsequent retrograde filling.

Taken from Wikopedia