Dental dams or rubber dams are essentially square sheets of latex used in dentistry, specifically endodontic treatment (root canals). They are also used during sexual activities as a safer sex technique.

A dental dam, also known as in Europe as a "Kofferdamm" (from German), is used mainly in endodontic treatment and when putting fillings into teeth. It is made from thin latex rubber. Because of possible latex allergy, it is also available in silicone.

The main function is to isolate the tooth being treated from its environment, in particular from the bacteria in the oral cavity. The rubber dam is held over individual teeth or groups of teeth by appropriate clips or threads (ligatures) along the edge of the gum. The tooth crown stands out from the rubber dam through individual holes made by hole pliers, and permits a clean and dry treatment — without admission of blood and saliva — of the appropriate tooth.

Routine use of dental dams is not always appropriate because of some difficulties: for instance communication with the patient is strongly reduced and the patient may feel restricted.