Make the Most of Your Mouth

A typical human mouth contains billions of bacteria. If you haven't brushed your teeth lately, you might well have more bacteria in your mouth right now than there are people living on planet Earth. Scientists have identified more than 700 different species of mouth-dwelling microbes.

There's no basis for concluding that a dog's mouth is "cleaner" than a human's. Both humans and dogs have mouths that are full of bacteria, and both contain roughly the same number of bacteria. And there are more than 100 different germs in dog (and cat) saliva that can make you sick.

While it's true that the longer food is on the floor, the more germs it will pick up, the "five-second rule" is arbitrary. Food starts to pick up germs from the moment it hits the floor. You're better off tossing it and eating something else.

Periodontal disease is not contagious. While bacteria that lead to gum disease can pass through saliva, gum disease typically develops if your teeth and gums aren't healthy. If your mouth is not healthy, you increase your risk through repeated and prolonged exposure to someone with periodontal disease. The American Dental Association recommends brushing twice a day and flossing daily. In addition, antibacterial mouthwash can help reduce plaque-causing bacteria that can cause gingivitis, an early, mild form of gum disease.

You should never share a toothbrush with someone else. The CDC advises that "the exchange of body fluids that such sharing would foster places toothbrush sharers at an increased risk for infections."

Studies have demonstrated that germs may be present on lipstick (including "tester" lipstick at cosmetics counters), lip balm, drinking glasses, band instruments, and many other items that may sometimes be shared.

Don't share such personal items if you want to avoid picking up potentially harmful bacteria, viruses, or other microbes.

The American Dental Association recommends rinsing your toothbrush with tap water after you use it, then letting it air dry. Keeping it in a closed container creates an ideal moist environment for the growth of bacteria.

According to the ADA, "there is no clinical evidence that soaking a toothbrush in an antibacterial mouth rinse or using a commercially available toothbrush sanitizer has any positive or negative effect on health." And using a dishwasher or a microwave could damage your toothbrush.

Experts recommend following similar advice for retainers or other dental devices that you put in your mouth, although additional disinfection with a denture cleanser may be recommended. Ask your dentist about the proper way to care for any particular dental devices that you may be using.

The American Dental Association recommends replacing your toothbrush every three to four months, sooner if the bristles are frayed. The ADA's main reason for replacement is to make sure your toothbrush is in good working order -- not because of bacteria. Although the group acknowledges that "various microorganisms can grow on toothbrushes after use," they maintain that there is "insufficient clinical evidence to support that bacterial growth on toothbrushes will lead to specific adverse health effects."

The American Dental Association has accepted many antiseptic mouth-rinse products for their "therapeutic benefits in reducing plaque and gingivitis." The group states that "these products have been demonstrated to kill the germs that cause bad breath." Of course, bad breath can be caused by things other than germs, such as eating garlic or other fragrant foods or poor dental hygiene. Certain medical conditions also can cause bad breath. In these cases, a mouth rinse may help mask your bad breath, but it won't address the cause of it.

Research indicates that green tea has been associated with healthier gums and lower odds for tooth loss.

While some bacteria are bad for your teeth and gums, others are critical to keeping them healthy. In fact, some helpful organisms in your mouth secrete substances that kill bad bacteria. Researchers are exploring a potential new kind of toothpaste based on a mouth bacterium that creates enzymes that prevent plaque formation.

Most of the bacteria in your mouth are part of a sticky film on your teeth known as plaque, which is the main cause of tooth decay. A single tooth can host 500 million bacteria. This is, of course, why you brush, floss, and rinse your teeth.