Root canals (endodontics)
The root canal is the treatment that saves teeth that would otherwise be pulled: infected pulp cleaned, sealed and crowned. It has a reputation worse than its reality.
When it is needed
Deep cavity reaching the nerve, trauma or infection at the root. The alternative —extraction plus implant or bridge— costs several times more than saving the tooth.
What to expect
One or two sessions under local anesthesia, mostly painless during and mildly sore after. Molars often get referred to an endodontist with a microscope — worth it for the complexity.
The crown after
A treated tooth is weaker and usually needs a crown, which is a separate line in the quote. Budget both together when comparing prices.