Even in these dire situations, provided there is enough tooth structure left to support some type of restoration, the tooth can still be saved by performing root canal treatment.
Root canal treatment involves working within the canals located in the middle of the root (hence root canal treatment), by removing the infected and dead tissue, sanitising the space with antibacterial disinfectants, and then finally sealing the space with a special filling material. This is all carried out under local anaesthetic, so there is no pain.
This procedure takes around 3 appointments to complete. In more straightforward cases, a root canal treatment can be performed in a single appointment; in more complicated cases, more than 3 appointments may be required.
Teeth become more fragile after a root canal treatment is completed, and will require protection to prevent fracture (usually in the form of a crown).