Refers to the procedure that involves "taking the nerve out of your tooth".
Every tooth is vitalised by the pulp which resides in the heart of the tooth. The pulp consists of nerves, blood vessels, some lymphatics and many undifferentiated mesenchymal cells.
Unfortunately several things can bring about the demise of your nerve : caries and trauma being the most common. The toothache pain you feel is known as pulpitis.
When the pulpitis is deemed irreversible, the only solution is to extirpate the pulp or extract the whole tooth.
Pulp extirpation involves giving a local anaesthetic to the tooth
creating an access cavity into the pulp chamber
locating the root canals in the tooth
inserting a file into the root canal
debriding the root canal with the file and irrigants
dressing the canal with medicaments
sealing the access cavity until the next appointment
more debridement and biomechanical preparation at the next appoinment
finally, obturating the root canal/s.
And there is the coronal filling which will ensure the longevity of the tooth.
Several x rays may be taken throughout these appointments to ensure that the canals are files to the right length, and rubber dam is used.