What Is a Dental Dam?

Dental dams are thin, flexible pieces of latex or polyurethane used as a barrier between the mouth and the vagina or anus during oral sex. Like external and internal condoms, they're designed to protect against sexually transmitted infections (STIs) and should be used only once.

Ready-to-use dental dams can be purchased online or at some drug stores; you also can make a DIY dental dam out of an external or internal condom.

History

Dental dams originally were developed for use by dentists to isolate areas of the mouth being treated and to prevent bacterial contamination.

In the 1990s, people began using dental dams for oral sex. In 1998, the condom company Glyde USA received approval from the Food and Drug Administration (FDA) for a latex dental dam designed for oral sex. Originally called Glyde Dam Lollyes, the product now is available as Sheer Glyde Dams.

Purpose

Dental dams can help reduce your risk of getting a sexually transmitted infection when used during oral-vaginal sex (cunnilingus) and oral-anal sex (anilingus, also known as rimming). They prevent the transmission of viruses and other microbes from one partner to another directly or via body fluids.

Dental dams can also act as a barrier against bacteria found in fecal matter such as Escherichia coli (E. coli), during oral-anal sex.

Types

Most dental dams are made of latex. However, there are versions made of polyurethane for people who are allergic to latex. To encourage their use, some manufacturers have created flavored dental dams.

Dental dams are most easily available online. They're sometimes sold in drugstores in the family planning aisle or from public health departments. Wherever purchased, dental dams are quite affordable: The typical cost is $1 or $2 each.

DIY Dental Dams

Dental dams aren't as readily available as external or internal condoms, but in a pinch, you can make your own using a non-lubricated latex or polyurethane external condom; it can be flavored if that's your preference:

1. Remove the external condom from the package and unroll it.
2. Using scissors, snip off the tip of the external condom.
3. Cut off the rubber base of the external condom.
4. Cut the external condom lengthwise from tip to base. Be very careful not to poke a hole in the condom as you trim it; otherwise, it will be useless.

How to Use

Using a dental dam is simple: During oral-vaginal sex, the dam is placed flat over the vulva to serve as a barrier between the mouth of the person performing oral sex and the vagina of the person receiving it. Similarly, during oral-anal sex the dental dam is placed over the anus to create a barrier between the mouth and the anus.

Once positioned, the dam must be held in place by either the person performing oral sex or the person receiving it. If it slips or is punctured, oral sex should be stopped immediately. The dam should be disposed of and replaced with a fresh one before sex is resumed. Used dental dams should be disposed of immediately.

Effectiveness

Few studies have examined the use of dental dams for preventing STIs, but, likely, they can substantially reduce the risk of infection from a wide variety of viruses and bacteria known to be transmissible via oral sex, including:

• Syphilis
• Gonorrhea
• Chlamydia
• HIV
• Human papillomavirus (HPV), which can lead to cervical cancer or head or neck cancers
• Herpes
• Trichomoniasis

The same goes for STIs associated with oral-anal sex:

• Hepatitis A and B
• Giardia or other intestinal parasites
• E. coli and other bacteria

A Word From Verywell

While the idea of using a dental dam during oral sex may seem unwieldy or unpleasant, it doesn't have to be if you make it part of the experience rather than a necessary precaution. If you have a partner who's reluctant to use a dental dam, think very carefully about proceeding, especially if they are not a long-term partner or someone you've just met. The encounter likely won't be worth the risk to your health or to theirs.