Introduction
Root canal content is whatever fills the canal when treatment starts: vital pulp (healthy or inflamed), necrotic or infected tissue, or an old root filling. Its state decides how it is removed – vital pulp whole and under anaesthesia, necrotic content gradually from crown to apex. Careless or incomplete removal is a common cause of post-operative pain, flare-ups, discoloration and failure.
Types of root canal content
Exstirpatio pulpae (Latin, "rooting out of the pulp"), or pulpectomy, is removal of the whole vital pulp, coronal and radicular. Gangraena pulpae is necrotic pulp decomposed by mainly anaerobic bacteria, with a foul smell. Devitalising pastes (arsenic trioxide, paraformaldehyde) are no longer recommended: they are toxic and leakage can necrose gingiva and bone.
The aims of removal: take out all organic tissue (the substrate for bacteria), the bacteria and their toxins, and make room for instruments, irrigant and the filling.
Vital pulp is removed in one piece under anaesthesia; necrotic content is removed in stages from crown to apex, with irrigation, and is never pushed apically.