Hello. My name is Dennis Cvitkovitch.
I'm a professor of microbiology at
the University of Toronto in the Dental Research Institute.
This lecture's topic will cover microbiota and its relationship to oral disease.
The human microbiome is a complex set of microorganisms that live on and within us.
They include bacteria, eukaryotic cells, and archeal cells.
In fact, every human has over 100 trillion microbes associated with them.
This is 10 times more than you'll find eukaryotic cells in the human body.
In fact, most cells in the human body are bacteria.
Bacteria that live in or on our bodies can affect the outcome of health versus disease.
The learning objectives of this lecture are that
you understand that the oral environment is
a complex dynamic ecosystem that is affected by both host and individual microorganisms,
and by the relationships of microorganisms both to each other and to the host.
Also, that oral infectious diseases have a very complex etiology,
and they are caused by environmental changes that
result in the overgrowth of pathogenic species over time.
And understand the structure and the formation of dental biofilm.
Here is a picture of human dental plaque.
You can see that the tooth on the left has been cleaned while
the tooth on the right remains with a thick layer of plaque material.
These teeth have been stained with iodine which stains
the extracellular polysaccharides produced by the biofilm, a yellowish color.
You can see that even though the bacteria in
the so-called plaque has been removed from the tooth on the left,
this very sticky extracellular polymeric substance stays behind.
This is important for attachment of the bacteria to the surface.