Microbes are everywhere, but did you know that there could be over 500 species of microorganisms on your teeth at any given time?
Microbes in your body are essential as they are the drivers of your digestive system, protect you against infection and make nutrients available for our bodies.
Biofilms are communities of microorganisms attached to a surface. Over 95 per cent of bacteria live in biofilms as this environment provides protection, nourishment and a stable habitat. Some common examples of biofilms include slime on bath tiles or pond scum.
“The majority of microbes on the planet exist in biofilms, and you have more microbial cells in your body than human cells. Naturally they exist in healthy and beneficial ways such as in the gut microbiome and its impact on our digestion… however biofilms can be negative if they are growing on knee or hip implants as they will treat that as a substrate,” said Dr. Laura Hug, a UW professor under the faculty of science and Canada Research Chair in Environmental Microbiology.
Why are there microbes on my teeth?
When you wake up in the morning or finish eating, you can usually feel a layer of white slimy stuff on your teeth known as dental plaque. This is formed from the interaction of bacteria in your mouth with sugary or starchy foods. Biofilm usually grows back within 24 hours of removal through brushing and flossing.
Some common microbes found in teeth biofilm include Streptococcus mutans and other anaerobes (bacteria that can grow without oxygen), such as Fusobacteria and Actinobacteria. These are acid-producing bacteria which, through the breakdown of carbohydrates in the food you eat, produce lactic acid, aspartic acid, etc., contributing to the acidic environment in your mouth.
The first step to the creation of these biofilms is attachment to a surface by bacteria. Teeth provide a stable habitat as there is a constant intake of nutrients from the food we eat. To adhere to the tooth’s surface, most bacteria use structures known as fimbriae — proteins surrounding the bacteria to help it stick. The second maturation step can then be seen as microbes begin to create an adhesive matrix on the surface, allowing cells to connect and produce a multilayer biofilm. This matrix is composed of a mixture of protein, DNA and sugars. Once they mature, cells can then spread from the biofilm layers to form new biofilms in different locations.
“If they aren’t attached to your teeth they are just going to get swallowed so that attachment component for anything as high flow as your mouth is really important, if they were not associated with biofilm they would lose the ability to stay in your mouth and migrate into your stomach… if microbes are in that biofilm there can be transfer of resources and it will add protection from dedication if you breathe through your mouth for example,” Hug added.
Biofilm pros and cons
“In your mouths, the microbes that are there are not actively doing any harm but they create a state of inflammation in the gums thus creating an immune response in your body producing irritation and swelling,” Hug said.
However, the biofilm on your teeth can act as a barrier against harmful oral bacteria. They do this through sequestering the oral bacteria, trapping it in sealed compartments within the matrix.
“You don’t want your mouth to be an incubation zone for something pathogenic that you’re then swallowing or pushing up into your nasal cavity and migrating to create an active infection,” Hug added.
Thus, brushing and flossing regularly gets rid of the biofilm and oral bacteria trapped within, which would otherwise turn into unwanted plaque if left uncleansed. The fluoride in drinking water has also been shown to help protect teeth against oral bacteria and help wash away biofilm regularly.