Is the rubber dam mandatory during a root canal?

Usually: A rubber dam is the standard of care during a root canal to keep reinfection down. If there is no way to keep it in place newer devices such as isodry, isolite and izolation can be tried to isolate the tooth as much as possible.

Yes: The key to success with a root canal is to sterilize the canal and keep it sterilized. A rubber dam is very effective at keeping saliva, which is full of bacteria, from getting into the canal.

Yes: Unless you want the root canal treatment to fail.