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Before You Share a Smooch: This is What Happens When You’re Exposed to Someone Else’s Saliva

Our mouths are loaded with hundreds of thousands of different micro-organisms. So, we can only wonder: What happens when we are exposed to someone else’s saliva.

The good news: We are at LOW RISK of transmitting infectious organisms to someone else through saliva. This is because saliva has antibodies and enzymes that decrease the risk of contagions.

The bad news: There is still a RISK. There are a number of micro-organisms that can work their way up from your saliva into your nose, throat and lungs — and THESE areas are the transmitters of illnesses like:

  • Rhinovirus (colds)
  • Flu virus
  • Epstein-Barr virus (mononucelosis, or mono)
  • Type 1 herpes (cold sores)
  • Strep bacteria
  • Hepatitis B and hepatitis C
  • Cytomegalovirus (a risk for babies in the womb)

Some of the new viruses, such as ebola virus and bird flu are also a concern. However, contrary to popular belief, the AIDS virus can NOT be transmitted through saliva.

3 Ways You Can Transmit Infection Though Saliva

1. Kissing.

It easy to exchange infectious organisms during a kiss through your saliva. You can spread colds and flu by kissing, although cold viruses usually spread by touching a contaminated surface and then your nose.

Your saliva typically protects you against bacteria in your partner’s saliva. (There will be more bacteria when oral hygiene is poor.) But one bacteria that can be transmitted is MRSA, the serious staph infection.

2. Sharing Toothbrushes.

The American Dental Association advises against this practice because someone else’s saliva can come in contact with tears in your mucous membrane and transmit infection. Sharing toothbrushes is especially risky if you have a weakened immune system.

Have a cold, sore throat or other virus? Keep your toothbrush from touching the family toothpaste and others’ toothbrushes.

3. Sharing Mouth Guards.

Mouth guards protect your teeth, mouth and jaw during sports, and may help keep you from grinding your teeth at night. Mouth guards, which are porous, should never be shared. A 2007 study, reported in General Dentistry, found that mouth guards harbor bacteria, yeasts and molds.

If you wear a mouthguard, be sure to:

  • Brush your  teeth before inserting it
  • Clean it whenever you brush your teeth
  • Store it in a case
  • Avoid chewing on it

Fortunately, the risk of saliva transmitting disease is very small. That means kissing is safe under most circumstances — thank goodness!


THE SCIENCE OF SMILES® offers affordable cosmetic and laser dentistry and gentle, compassionate general dental care in Pasadena, CA. Our office is conveniently located with extended hours to meet your needs. At THE SCIENCE OF SMILES®, we provide most dental services, from basic preventative care and general dentistry to specialized procedures, complete dental reconstruction and TMJ/Headache management. Patient satisfaction is our top priority and we strive to provide the exceptional, affordable dental care and personal touch that lead to lasting relationships. A smiling patient is our greatest reward and we look forward to keeping those smiles healthy, beautiful, and bright. Discover affordable up-to-date dentistry and a team who truly cares at THE SCIENCE OF SMILES®.