Dental Dam

Medically Reviewed by Carmelita Swiner, MD on August 03, 2022
3 min read

A dental dam is a square, stretchy sheet made from latex or polyurethane plastic. It blocks the body fluids that can spread sexually transmitted diseases (STDs).

Most people think of latex condoms when they want to protect themselves and their partners from STDs. But they're not the only barrier method. A dental dam is another form of protection you can use when you have oral sex.

Oral sex is less risky than vaginal or anal sex. But you can still get an STD from exposure to your partner's body fluids. A dental dam, placed over your partner’s genitals or anus before you have oral sex, will make that less likely.

The name comes from its original use. Some dentists use a thicker version to keep their patients' teeth dry and germ-free during dental procedures.

You can buy dental dams in many of the same places you get condoms, like drugstores and online. Sexual health clinics may offer them for free. Some come in flavors like strawberry or banana.

A dental dam keeps your mouth from making direct contact with your partner's genitals and fluids. When you use it the right way, it can make it less likely that you’ll get HIV and other STDs like:

You use a dental dam on the vulva (female genitals) and anus. When you have mouth-penis oral sex, it’s better to use a condom for protection.

Some conditions could spread despite a dental dam, including:

  • Pubic lice (crabs). These tiny insects spread through close personal contact or personal items like clothing.
  • Scabies. You can also pick up these mites from skin or fabric.
  • Genital warts. You could catch HPV, which causes these warts, from one that’s outside the area covered by a dental dam.
  • Herpes. Like warts, you can get the herpes virus from a sore that’s not covered by a dental dam. It’s also possible for someone who doesn’t have any symptoms to spread the virus.

First, check that it hasn't expired and that there aren't any tears in the package or in the latex. Wash off any cornstarch. It could cause an infection in the vagina.

You can use a water- or silicone-based lube, but don't use anything oil-based like baby oil or petroleum jelly. This could weaken the plastic.

Place the dental dam flat against the vulva or anus. You or your partner will need to hold it there the whole time you’re having oral sex.

Throw the dental dam away after you’re finished. Don't turn it over and reuse it. You could expose yourself to the germs that cause STDs.

If you're in the mood but you don't have a dental dam, a nonlubricated latex condom will work. Here’s how to turn it into a dental dam:

  • Cut off the top and bottom of the condom.
  • Cut down one side to make a flat sheet.
  • Use it the same way you would a dental dam.

You can also use a latex glove for protection.

  • Cut off the fingers and base.
  • Cut down one side of the glove to make it flat.

For times when you don't have a condom or latex glove, plastic wrap may also work. Just know that there’s no research on how well it blocks STDs. And make sure there are no rips in the plastic.

A dental dam is a barrier, so oral sex may feel different than it does without one. But the material is thin enough that you should be able to feel your partner's touch through it.

To increase the sensation, apply a water-based lubricant.

What to do:

  • Use a new dental dam every time you have oral sex.
  • Read the instructions first, and be sure it hasn’t expired.
  • Check for tears or other problems before using it.
  • Put it in place before you start oral sex. Keep it there until you’re finished.
  • Store unused dental dams in a cool, dry place.

What not to do:

  • Don’t reuse a dental dam.
  • Don’t stretch it, which could cause tears.
  • Don’t use baby oil, lotion, petroleum jelly, or cooking oil as a lubricant. They could cause the plastic to break.
  • Don’t use a dental dam along with the spermicide nonoxynol-9. It may cause irritation.
  • Don’t flush a dental dam down the toilet. Throw it away in the trash instead.