A dental dam or rubber dam is a thin, 6-inch (150Â mm) square sheet, usually latex or nitrile, used in dentistry to isolate the operative site (one or more teeth) from the rest of the mouth. Sometimes termed "Kofferdam" (from German), it was designed in the United States in 1864 by Sanford Christie Barnum. It is used mainly in endodontic, fixed prosthodontic (crowns, bridges) and general restorative treatments. Its purpose is both to prevent saliva interfering with the dental work (e.g. contamination of oral micro-organisms during root canal therapy, or to keep filling materials such as composite dry during placement and curing), and to prevent instruments and materials from being inhaled, swallowed or damaging the mouth. In dentistry, use of a rubber dam is sometimes referred to as isolation or moisture control.
Dental dams are also used for safer oral sex.