Is the plaque on your teeth a tiny city of microbes?
Centuries ago, Antonie van Leeuwenhoek found tiny "animalcules" on his own teeth. Dental plaque is a city with about 1,000 kinds of residents.
▶ Start the storyThe plaque on your teeth is a living community: a of microorganisms, mostly bacteria but also fungi, that grows on surfaces in the mouth. About 1,000 different bacterial species have been recognised in plaque with modern techniques, and 80 to 90 percent of its weight is water. The mouth, along with the gut, shows the greatest bacterial richness of any body site, more than skin.
Plaque builds up in steps. Shortly after teeth are cleaned, a thin film of saliva proteins called the acquired forms. Bacteria attach to it, form small colonies and mature. Streptococcus mutans, one of the main members, uses an enzyme to turn sucrose into a sticky that lets the bacteria cohere. A also shields its members from the environment and from .
Step 1:
A film of saliva proteins forms on a clean tooth.
Step 2: Attachment
Bacteria stick to the .
Step 3: Micro-colonies
They multiply into small colonies.
Step 4: Sticky glue
Streptococcus mutans turns sucrose into a sticky .
Step 5:
A mature community of about 1,000 species, mostly water by weight.
The mouth is a good home for them. Unlike skin, tooth surfaces are hard and non-shedding. Saliva and the fluid around the gums carry amino acids, proteins and that feed the plaque bacteria.
These microbes occur naturally in the mouth and are normally harmless, which is a useful reminder that plaque itself is not an invasion. The trouble comes with what they produce. Tooth decay is the destruction of tooth tissue by acid made when bacteria break down , and saliva cannot get through a thick build-up of plaque to neutralise that acid.
The first person to see this world was Antonie van Leeuwenhoek, who built his own microscopes. He found his "animalcules" everywhere, including on his own teeth.
Quiz me
0/3
Recap
Plaque is a sticky biofilm of about 1,000 species; its members are normally harmless, but the acid they make from sugar harms teeth.
💡 A trick to remember it · A tooth is a hard, bare beach with no shedding skin, so the bacterial city builds on it with its own glue.
Surprising fact · Leeuwenhoek found "animalcules" on his own teeth, and plaque is mostly water by weight.
Sources (3)
No source, no claim. Every fact in this lesson (15 claims) cites at least one of these.