A dental dam is a thin, flat sheet of latex (or sometimes non-latex material) that acts as a barrier between skin or tissue and whatever is on the other side. It has two distinct uses: in dentistry, where it isolates teeth during procedures, and in sexual health, where it reduces the risk of infection during oral sex. The term shows up in both contexts, which is why a simple search can return confusing results.
The Original Dental Use
The dental dam was invented in 1864 by Dr. Sanford Christie Barnum, an American dentist. In a clinical setting, it’s a square sheet of thin rubber stretched over a small frame and clamped around a tooth. This keeps the working area dry by blocking saliva, and it prevents tiny fragments of filling material or tooth from being swallowed or inhaled. If you’ve ever had a filling, root canal, or crown preparation, there’s a good chance your dentist placed one of these over the tooth being worked on.
The Sexual Health Use
Outside the dental office, a dental dam serves as a barrier method for safer oral sex. You place it flat over the vulva during oral-vaginal sex or over the anus during oral-anal sex. It works the same way a condom does: by creating a physical layer between one person’s mouth and the other person’s skin or mucous membranes, blocking the exchange of bodily fluids that can carry sexually transmitted infections.
STIs that can be transmitted through oral sex include herpes, HPV, gonorrhea, syphilis, and in some cases hepatitis. A dental dam doesn’t eliminate all risk, since some infections spread through skin-to-skin contact in areas the dam doesn’t cover, but it significantly reduces exposure.
How to Use One for Oral Sex
Using a dental dam correctly is straightforward. Open the package carefully and unfold the sheet. Lay it flat so it covers the entire vaginal or anal area. Hold it in place with your hands during oral sex, and keep it flat against the skin without stretching or bunching it. If the dam slips out of position or tears, stop and replace it with a new one.
A few practical tips make the experience better and safer:
- Use lubricant on the skin side. A small amount of water-based or silicone-based lubricant between the dam and the skin increases sensation and reduces the friction that can cause tearing.
- Avoid oil-based products. Baby oil, lotion, petroleum jelly, and cooking oil all weaken latex and can cause the dam to break.
- Use it once. Each dental dam is single-use. Throw it away in the trash afterward, never reuse it or flip it over.
- Don’t switch sides. Keep track of which side faces your partner’s body. Flipping it mid-use defeats the purpose.
Making One From a Condom
Dental dams aren’t always easy to find in stores, which is one reason they’re underused compared to condoms. If you don’t have one on hand, you can make a functional barrier from an unlubricated or flavored condom. Cut off the tip and the base (the rolled ring), then cut down one side lengthwise. You’ll end up with a rectangular sheet of latex you can lay flat and use the same way. It’s not a perfect substitute for a manufactured dental dam, which tends to be larger and more uniform, but it provides meaningful protection in a pinch.
Materials and Alternatives
Most dental dams are made from latex, but non-latex versions made from nitrile or polyurethane exist for people with latex allergies. These work the same way and are compatible with the same water-based and silicone-based lubricants. Some brands sell flavored dental dams designed specifically for oral sex, which can make them more appealing to use.
You can find dental dams at pharmacies, sexual health clinics, and online retailers. They’re sometimes distributed free at college health centers and STI testing sites. If you’re buying them, they typically cost a few dollars for a pack, making them one of the cheapest barrier methods available.
Why They’re Rarely Used
Despite public health recommendations, dental dams are among the least commonly used barrier methods. Surveys consistently show that most people have heard of them but very few use them regularly. The reasons are practical: they’re harder to find than condoms, they require one person to hold them in place, and many people underestimate the STI risk from oral sex in the first place. None of that changes the fact that oral sex can transmit infections, and a dental dam is the only barrier method specifically designed for that purpose.