Dental dams isolate teeth and clear the field -- or the area being worked on -- of excess moisture. Most often dams are used for endodontic procedures, such as root canals or other interior and below-tooth work because controlling the amount of saliva on the exposed area reduces some of the bacteria that can get inside and cause infection and/or irritation. Dams also keep instruments and pieces of composite material of the tooth itself from going down the oral cavity and into the body.
Additionally, when the mouth, lips and tongue are covered by a dam, there is less likelihood that sharp tools can nick tissue and lead to bleeding or blood and saliva sprays that can endanger dental professionals if a patient has an infectious disease. Some professionals also use dams for non-endodontic and minor procedures such as replacing fillings, making molds of teeth or even whitening teeth, for example, simply to protect the patient from swallowing debris or to keep teeth as dry as possible for receiving overlays and coatings.
Both dental assistants and dentists must show proficiency in fitting and removing dental dams, but some studies find that, in practice, many dental professionals don't use them. Reports published by the National Institutes of Health (NIH) in the U.S. showed that between 53 and 63 percent of dentists surveyed didn't use dental dams at all. Their reasons for not using them ranged from inconvenience and irrelevance to their procedures to patients refusing to wear them, among others [sources: ADA; Gilbert; Hill]. Combined, these surveys included less than 1,000 practicing respondents, but if representative of dentistry as a whole, does it even matter if dental dams are used?
According to the Centers for Disease Control and Prevention (CDC) and the American Association of Endodontists (AAE), it does matter. Dental dams are effective in limiting the spread of bacteria into the area of the mouth that is exposed during procedures and in keeping the same bacteria from being swallowed or taken in internally. These rubber sheets also serve to protect dentists, hygienists and patients from possible exposure to HIV, hepatitis and other infectious diseases or blood-borne pathogens during procedures.
Using a dental dam is mandatory for certain endodontic procedures in the United States, and according to the AAE it should be the required standard of care. It is a recommended "universal precaution" in CDC statements on infection in dental care practice. Additionally, it adds protection for dentists by decreasing liability if a patient swallows or chokes on something during treatment [sources: AAE; CDC].
How do patients take to dental dams and can they choose whether or not to, ahem, dam it?