Germs Quiz: What Lives in Your Mouth?

The number of bacteria in your mouth is closest to the population of which of the following?
New York City
The United States
North America
Earth
The number of bacteria in your mouth is closest to the population of which of the following?
A typical human mouth contains billions of bacteria. If you haven't brushed your teeth lately, you might well have more living there right now than there are people on Earth.
Scientists have identified more than 700 different species of microbes -- ultra-tiny living things such as bacteria -- that are in people's mouths.

A dog's mouth is cleaner than a human's.
True
False
A dog's mouth is cleaner than a human's.
There's no basis for this myth. The mouths of humans and dogs both have roughly the same number of bacteria. And there are more than 100 different germs in dog (and cat) saliva that can make you sick.

If you drop food on the floor, it doesn't get germs on it if you pick it up within 5 seconds.
True
False
If you drop food on the floor, it doesn't get germs on it if you pick it up within 5 seconds.
While it's true that the longer food is on the floor, the more germs it will pick up, the "5-second rule" isn't real.
Food starts to pick up germs from the moment it hits the floor. You're better off tossing it and eating something else.

Anyone who kisses someone with gum disease will always get it.
True
False
Anyone who kisses someone with gum disease will always get it.
It's not contagious. While bacteria can pass through saliva, gum disease typically develops if your teeth and gums aren't healthy.
If your mouth isn't healthy, you increase your risk for gum disease through repeated and lengthy exposure to someone who's got it. To help keep germs away, brush, floss, and use an antiseptic mouthwash daily.

If you find yourself without a toothbrush, it's a good idea to borrow a friend's.
True
False
If you find yourself without a toothbrush, it's a good idea to borrow a friend's.
You should never share it with someone else. The CDC says that raises your risk of getting an infection.

Which of the following items can transfer potentially dangerous microbes between people?
Lipstick
Drinking glasses
Band instruments
All of the above
Which of the following items can transfer potentially dangerous microbes between people?
Studies show that germs may linger on lipstick, drinking glasses, band instruments, and other personal items.
Don't share them if you want to avoid picking up potentially harmful bacteria, viruses, or other microbes.

To protect your toothbrush from harmful germs, you should:
Leave it out in the open air
Store it in a closed container
Soak it in an antibacterial mouthwash
Microwave it for 15 seconds
To protect your toothbrush from harmful germs, you should:
The American Dental Association recommends that you rinse your toothbrush with tap water after you use it, then let it air dry. Keeping it in a closed container creates an ideal moist environment for the growth of bacteria.

To avoid the buildup of bacteria, the American Dental Association recommends replacing your toothbrush every month.
True
False
To avoid the buildup of bacteria, the American Dental Association recommends replacing your toothbrush every month.
The group suggests you get a new one every 3 to 4 months, or sooner if the bristles are frayed or after you're sick. Your toothbrush won't do a good job cleaning your teeth if it's worn down.

Antiseptic mouthwashes can keep your gums and teeth healthy.
True
False
Antiseptic mouthwashes can keep your gums and teeth healthy.
Rinsing with one not only keeps your breath fresh, it can also help reduce plaque, the film of bacteria that forms on your teeth. It lowers inflammation of your gums, too.
Many dentists recommend using an antiseptic mouthwash twice a day.

Drinking green tea may help keep your teeth and gums healthy.
True
False
Drinking green tea may help keep your teeth and gums healthy.
Research shows that it's linked to healthier gums and lower odds for tooth loss.

All bacteria are bad for the health of your teeth and gums.
True
False
All bacteria are bad for the health of your teeth and gums.
While some bacteria are bad for your teeth and gums, others play a key role in keeping them healthy. Researchers are exploring a potential new kind of toothpaste based on mouth bacteria that create enzymes that prevent plaque.

Most bacteria in your mouth live in plaque.
True
False
Most bacteria in your mouth live in plaque.
Most microbes 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 use an antiseptic mouth rinse.

Bacteria in your mouth can cause tooth decay by:
Eating tooth enamel
Releasing acids that weaken tooth enamel
Releasing sugars that destroy tooth enamel
All of the above
Bacteria in your mouth can cause tooth decay by:
When you eat, the outer shell of your teeth, called enamel, can get weakened from acids given off by bacteria on your choppers. Fluoride in toothpaste and mouth rinses can help strengthen your enamel and prevent cavities.

Research has shown a link between gum disease and:
Cardiovascular disease
Diabetes
Alzheimer's disease
All of the above
Research has shown a link between gum disease and:
Harmful bacteria in your mouth can lead to gum disease, which has been linked to a number of other diseases. It was once believed that the bacteria were the culprit, but researchers have begun to think that inflammation caused by the bacteria is the key factor.