Nerve injuries related to root canal treatment (or endodontics)

Treating  pulpitis (a dead tooth pulp) is complex and requires cleaning out of the pulp chamber within the tooth. Ideally the whole canal is chemically and mechanically debrided (cleaned), however, if the tooth root is close to the inferior alveolar nerve canal in the jaw bone, ensuring that the caustic chemicals used for cleaning do not leak out of the apex of the tooth is difficult.

The chemical pH of these chemicals is extremely high and extremely noxious (poisonous) to nerve tissues. This is one way that nerves can be damaged by root canal treatment. The other causes are over instrumentation (protruding instruments through the tooth apex) and over filling (too much filler applied and leaks through the end of the tooth).These injuries are associated with high level pain and permanency, hence urgent care is required.

Prevention of these nerve injuries is possible with various strategies

Links below:

Risk Assessment Part 1
Risk Assessment Part 2
Altered pain modulation in patients with persistent postendodontic pain
ENDO nerve injuries
Prevention of restorative nerve injuries