What Really Causes Cavities?

What Really Causes Cavities?

Posted: January 28, 2016

Did you know that you have whole communities of microbes living in your mouth right now? And if you don’t treat them right, they’ll make holes in your teeth.

I’m Anna Rothschild, and this is Gross Science.

No matter how much you brush, your mouth is filled with microbes. Thousands of bacteria live on every single one of your teeth—and that’s if you have excellent oral hygiene! You may even have some fungi and amoebas in there, too.

Which microbes are present changes all the time, based on, say, who you’re dating. We swap something like 80 million bacteria with every 10-second-long French kiss, and couples who live together tend to have similar microbes on their tongues. That said, there is what scientists call your “core microbiome.” That’s the 150-ish different species of microbes living in most people’s mouths.

Now, lots of these guys are totally harmless—and some are even helpful. For example, some microbes help keep you from getting thrush, which is a yeast infection of the mouth.

Increasingly, we’re learning that to have a healthy mouth we need healthy microbes, as well. In fact, cavities are a good example of what can happen when the balance of microbes in your mouth gets out of whack.

Many of the microbes living on your teeth form something called “plaque,” and in small quantities, these guys can be our friends. Plaque is what’s called a “biofilm”—essentially a community of different microbes that all stick to a surface, in this case, your teeth. The crazy thing is that these different microbes talk to each other, passing molecular signals back and forth, and swapping genetic material to keep on growing. Eventually, the community even develops what you could think of as a circulatory system to transfer water and nutrients.

And speaking of nutrients, the microbes in these biofilms need to eat, and one thing some of them really love is sugar. So, when you suck on a lollipop, you’re not the only one getting a tasty treat. After their meal, these candy and soda-hungry microbes release acid as a waste product. And that acid is what pulls out the minerals in your teeth, eventually causing cavities.

Now, if you stop eating sugary foods and clean off the plaque by brushing, your teeth have a chance to recover. But if, for example, you drink soda all the time, the bacteria just produce more and more acid, which not only causes cavities, but could actually kill off some of the other, good microbes hanging around. And as the balance of bacteria in your mouth changes, you could get even more tooth decay and other dental problems.

So what can you do about it? Don’t eat too many sugary foods, remember to brush and floss, and get regular cleanings from your dentist. Cause we need to keep our communities of microbes happy and healthy.

Ew.

PRODUCTION CREDITS

Host, Writer, Animator, Editor

Anna Rothschild

Camera, Sound

Katherine Hashimoto

Many thanks to Drs. Susan Perkins, Rob DeSalle, and Anne Tanner

Toy Box

Music Provided by APM

Original Footage

©WGBH Educational Foundation

FOOTAGE AND IMAGES

Dental Plaque, SEM

Steve Gschmeissner/Science Photo Library

Dental Plaque Bacteria in Phase Microscope 600X Blue Filter

Pond5/jamesbenet

Lovers Kissing Romantic Romantic Beautiful Kissing Teens Couple in Hd

Pond5/TH_Producties

Elderly Couple

Pond5/Fotoluminate

Dental Plaque From Human Sample 800Z Microscope

Pond5/jamesbenet

Devan

Flickr/Seth Lemmons

Candida albicans 2

Wikimedia Commons/GrahamColm

Decayed wisdom tooth

Wikimedia Commons/ProjectManhattan

Dental cavity1

Wikimedia Commons/Digantatalukdar

Digital cavity2

Wikimedia Commons/Digantatalukdar

Double big gulp

Wikimedia Commons/Russell Bernice from New York City, USA

Plaque Disclosing Tablets

Wikimedia Commons/Themolarbear

File: Sugar Cubes (7164573186)

Wikimedia Commons/david pacey from LEEDS, West yorkshire

File: The Dental cosmos (1912) (14769050452)

Wikimedia Commons/White, J.D. McQuillen, J.H. (John Hugh), 1826-1879. Ziegler, George Jacob, 1821-1895. White, James William, 1826-1891. Kirk, Edward C. (Edward Cameron), 1856-1933. Anthony, L. Pierce (Lovick Pierce), b. 1877.

File: Phagocytose Entamoeba gingivalis-PMN

Wikimedia Commons/Mark Bonner dmd, Institut International de Parodontie, www.parodontite.com

Oral thrush. Aphthae. Candida albicans.

CDC

SFX

Dun dun dun

Freesound/Simon_Lacelle

Squeak Pack/squeak_10

Freesound/Corsica_S

Jelly/Jelly Mangling on Plate

Freesound/lolamadeus

Bubbles Popping

Freesound/ch0cchi

Produced by WGBH for PBS Digital Studios

POSTER IMAGE

Microbes and Lollipop

©WGBH Educational Foundation 2016

Want more info?

Welcome to the Microbiome, by Susan Perkins and Rob DeSalle:
http://amzn.to/1PtAi3u

Kissing and the microbiome:
http://bit.ly/1PNCkFH

More on thrush from the CDC:
http://1.usa.gov/1KyxNp2

The Role of Bacteria in the Caries Process:
http://bit.ly/1PNDPDQ