A local anaesthetic is applied to prevent any discomfort, and the process should feel the same as being given an ordinary filling. It does take longer, however, and will usually involve at least two visits. During the first visit, your dentist will remove all of the infected pulp from the root canal and drain any abscesses. The root canal is then cleaned, and a temporary filling applied. More visits are required to check for further infection. Once your dentist is satisfied that all the infection has been cleared, you will be given a permanent filling.