How does a rubber dental dam work?

Isolation!: A rubber dam is use a sheet of rubber with holes punched in it. It is placed over the patient's mouth and the teeth poke through the holes. A small metal clip is then attached to one of the teeth to hold things in place. The purpose is to keep the patient's check, lip, and tongue out of the way while preparing the teeth and then to keep good moisture control while placing fillings.

Surgical drape: Think of a rubber dam as a surgical drape to isolate the tooth from the oral cavity and to prevent contamination. Just like a surgeon during an operation.

Oral barrier: They are small thin pieces of latex (or other materials) that fit around tooth/teeth while the dentist is working. It enhances visibility when working, prevents saliva from seeping into the working field, and prevents aspiration of dental dental materials and tools.