Condoms and dental dams
Section menu
On this page
- How condoms work
- Types of condoms
- How to use condoms effectively
- If a condom breaks
- How dental dams work
- How to use dental dams effectively
How condoms work
Condoms are protective barriers you can use during sex to:
- prevent body fluids from being passed from one person to another
- fluids include blood, semen and vaginal discharge
- reduce skin-to-skin contact
When used properly, they can:
- reduce the risk of many infections passed through sex
- help prevent unplanned pregnancies by blocking semen from entering the vagina
Types of infections condoms protect against
Infections that are passed through sex are called sexually transmitted infections (STI). Common STIs include:
- syphilis
- chlamydia
- hepatitis B
- hepatitis C
- gonorrhea
- trichomoniasis
- herpes simplex virus (HSV)
- HPV (human papillomavirus)
- HIV (human immunodeficiency virus)
Some of these infections can be passed through blood, such as HIV, hepatitis B and hepatitis C. These are also called sexually transmitted and blood-borne infections (STBBI).
Condom effectiveness
How effective a condom is in preventing an STI depends on the:
- type of infection it’s being used to protect against
- type of condom being used
Condoms are particularly effective against infections that are spread through body fluids, such as gonorrhea, chlamydia and HIV.
However, condoms are less effective against infections that are spread through skin-to-skin contact, such as genital herpes and syphilis. This is because these infections can be transmitted through areas not covered by the condom.
The effectiveness of condoms in preventing unplanned pregnancy depends on how they’re used. With perfect use, external condoms are 98% effective and internal condoms are 95% effective in preventing unplanned pregnancy. Effectiveness can be lower due to improper use, damage or using an expired condom.
Contraceptive methods like birth control pills, IUDs (intrauterine devices) or spermicides do not protect against STIs. Using condoms as well as these methods can prevent both STIs and unplanned pregnancy.
Condoms are medical devices, and Health Canada regulates their testing, packaging and labelling. If you think a batch of condoms may be defective, report your concerns.
Report a defective batch of condoms to Health Canada
Learn more:
Types of condoms
There are different types of condoms that come in many sizes, shapes, colours and textures. Try a few different ones to find which works best for you.
External condoms
External condoms cover the penis to create a protective barrier. When used properly, external condoms rarely break and leaks are even less common.
Condoms need to fit properly to be comfortable and effective. If they’re too loose they can slip off, and if they’re too tight they may be more likely to break. Condom packaging includes size by width so that you can find the kind that fits you best.
Latex condoms protect against STIs better than non-latex condoms because they don’t break and slip as often. Natural membrane condoms do not protect against STIs.
Do not use 2 condoms at the same time, as it increases the risk of a condom breaking.
Latex condoms
Condoms made from latex rubber are the most common.
Only use silicone or water-based lubricants with latex condoms. Do not use petroleum or oil-based lubricants with latex condoms as they can weaken the latex. This can cause the condom to tear or break more easily.
Latex condoms may cause skin irritation or an allergic reaction for some people. If you’re allergic to latex, use synthetic polymer or natural membrane condoms.
Some medications intended for vaginal use (like yeast infection treatments) can weaken latex condoms. Treatments that contain estrogen are especially damaging to latex condoms.
Synthetic polymer condoms
Synthetic polymer condoms are usually made of polyurethane, which is similar to latex. This material is effective in preventing pregnancy and STIs.
This type of condom is a good option for people who are allergic to latex. Silicone and water-based lubricants are safe to use with these condoms. Read the product label to see if other types of lubricants are safe to use with synthetic polymer condoms.
Natural membrane condoms
Natural membrane condoms are made from the lining of sheep intestines. They contain microscopic holes that are small enough to prevent semen from getting through the barrier, and can prevent pregnancy. However, the holes are too large to prevent the spread of certain STIs, including HIV.
Only use natural membrane condoms to prevent pregnancy, not to prevent STIs.
Learn more:
Lubricated condoms with spermicide
Condoms with spermicide are coated with a lubricant containing nonoxynol-9 (N-9). N-9 can kill sperm to further reduce the risk of pregnancy.
Condoms with N-9 are not recommended. They may cause irritation to the penis and tissue inside the vagina and rectum, which can increase the risk of passing on an STI. N-9 has also been associated with increased UTIs (urinary tract infections) in females.
Internal condoms
Internal condoms are liners inserted and worn inside the vagina or anus to prevent semen from entering the body. They’re usually made of polyurethane or latex.
Some medications intended for vaginal use (like yeast infection treatments) can weaken latex condoms. Treatments that contain estrogen are especially damaging to latex condoms.
Do not use an external condom and an internal condom at the same time, as it increases the risk of a condom breaking.
Novelty condoms
Condoms with novelty designs, textures and other features are not recommended for contraception or STI prevention.
Do not use novelty condoms together with latex condoms, as layering them can create friction that increases the risk of tearing or slipping. Some novelty condoms are also made from materials that can weaken latex, making them even less effective at preventing pregnancy and STIs.
How to use condoms effectively
Reduce the risk of STIs by:
- storing condoms at room temperature and out of direct sunlight
- checking the expiry date on the package, as expired condoms may not work properly
- using the right type of lubricant to reduce the chances of a breakage
- following the directions on the package
- using a new condom with each new sex act
- not using 2 condoms at once because if they rub on each other, they can rip or slip off
- this applies to both external and internal condoms
If a condom breaks
If a condom breaks, tears or slips off during sex, there may be a chance of:
- pregnancy
- passing on or getting an STI
Seek immediate medical advice if a condom breaks during sex with someone:
- living with HIV who has a detectable viral load (more than 200 copies of HIV per milliliter of blood) or
- with an unknown HIV status
Medication called HIV post-exposure prophylaxis reduces your risk of getting HIV when taken within 72 hours of potential exposure.
If you’re concerned about pregnancy, talk to a health professional about emergency contraception options.
Learn more:
How dental dams work
Dental dams are latex or polyurethane sheets of about 10 inches by 6 inches that act as a barrier between the mouth and vulva or anus during oral sex. They protect both users from the spread of STIs through sexual contact and body fluids.
Dental dams are available without a prescription:
- online
- at drug stores
- at health clinics
- at specialty sex shops
How to make a homemade dental dam using an external condom
How to use dental dams effectively
Reduce the risk of STIs by:
- storing dental dams at room temperature and out of direct sunlight
- checking the expiry date on the package, as expired dental dams may not work properly
- using a water-based or silicone-based lubricant to prevent breakage
- following the directions on the package
- using a new dental dam with each new sex act
Related links
Page details
- Date modified: