A tooth is made up of a crown (the white bit that we can see in the mouth) and the root(s). Within the root(s) of a tooth there are canals which contain the nerve and blood supply – known as the pulp. Each tooth has different numbers of roots and thus canals.
Root canal treatment can also be called Endodontics. This type of treatment is needed when the pulp is irreversibly infected/inflamed due to decay or trauma.
Root canal treatment should feel just like a filling; however, the process does take longer. You should not experience any pain during a root canal treatment.