A dental dam or rubber dam (sometimes termed “Kofferdam”–from German), is a thin, rectangular sheet, usually latex rubber, used in dentistry to isolate the operative site (one or more teeth) from the rest of the mouth. It is used mainly in endodontic, fixed prosthodontic 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.
Dental dams may also be used as a safe sex technique to reduce the risk of sexually transmitted diseases (STDs) during cunnilingus and other sexual activities, although they are rarely used for this purpose.
Sometimes dental dams are promoted during safe sex campaigns, for use during cunnilingus and anilingus. However, among women who have sex with women, they are rarely used for this purpose, and there is no good evidence that their use reduces the risk of STD transmission in this group, including the risk of infection with human immunodeficiency virus. After lubrication with a water-based lubricant, an unpunctured dental dam may be held over the vulva or anus, allowing oral stimulation of these areas without transmission of bodily fluids and direct physical contact.