Could they need to use a rubber dam for a root canal?

Yes: The use of a rubber dam is mandatory for root canal treatment. Not using one increases the risk of harm to the patient due to chocking hazard or chemical exposure. Also the risk of leakage of saliva into the tooth goes from nonexistent to high when a dam is not used. If a rubber dam isnt going to be used, you are justified in requesting treatment somewhere else, .

It should be used: The standard of care across the United States is using a rubber dam for root canal procedures. There may be some exceptions and they are individualized per the patient mouth/tooth anatomy.