Lectures # 8-9 Oral Ecology & Biofilm Flashcards
What are biofilms?
Matrix-enclosed bacterial populations adherent to each other and/or or to surface or interfaces, bacteria products, and salivary proteins.
As long as these ________________, bacterial ________________ are fed well and maintained properly they generally cause little problem
- normal flora
- biofilms
Note: If not fed properly (too many sweets, poor hygiene) disease can follow.
What is the new thinking of microbial colonization of living host?
Microbes do not live as separate individual colonies but rather as complex communities called biofilms.
What are the basic biofilm properties?
1) cooperating communities of different microorganisms
2) Microorganisms are arranged in microcolonies
3) Microcolonies are surrounded and attached together by protective matrix
4) Within and between, the micro colonies are differing environments
5) Microorganisms have primitive communication system
6) Microorganisms in biofilms are more resistant to antibiotics, antimicrobial and host responses
As the plaque in the mouth frows thicker it becomes less _________ to _______ and ______________
- permeable
- oxygen
- saliva
Thicker plaque builds up what?
- HIGHER concentrations of TOXIC products, acids, and inflammatory bacterial components.
- These changes with increased thickness and density result in growth of different species and changes the character of the dominant plaque organisms.
Which species are the dominant species of the biofilms?
Step and Actinomyces
What changes can be observed with build up of plaque and poor hygiene?
- Increased inflammatory materials (e.g, FMLP, cell wall products, and probably most importantly LPS) around the gingival crevice causes, gingivitis and eventually a pseudopocket and then real pockets and increased growth of gram - (best suited for anaerobic ,CO2 rich, asaccharolytic enthronements of deeper pockets.
- Eventually this can lead to the loss of attachment we call periodontal disease, and are available to infect the tooth pulp if the hydroxyapatite shell is breached.
What benefits can the normal flora provide?
-Bacteria that exist in “equilibrium” w/ the host and generally do not cause disease.
(inhibit the colonization of pathogenic organisms)
(Inhibits colonization of pathogenic microorganisms, produce vitamins that are required by the host.)
What is supplemental flora?
Found in a minority of the population where they generally act like normal flora
Example: Women that carry S. aureus in their vaginal flora where it doesn’t cause disease
What does transient flora consist of?
- Microorganisms that are brought to the area from somewhere else (via contamination?)
- They almost always have a difficult time colonizing and competing in the area, generally cleared within hours or days.
Microbial flora falls into what 3 major groups?
1) Normal flora
2) Supplemental flora
3) Transient flora
What are the roles of normal flora?
1) Competition
2) Vitamin K synthesis
3) Immune stimuli: LPS–> GUT INCREASE DTH, etc
4) Source of opportunists
5) Etiologic agents of caries & chronic inflammation periodontal disease
What is oral ecology?
Colonization of the oral cavity and formation of plaque biofilm
During birth a child’s oral cavity is colonized by what?
Vaginal microorganisms that can survive in the mouth (e.g., Candida, Lactobacillus, etc )
-Baby continues to be colonized by other microbes from “kissing” etc.
When the teeth erupt into the mouth, what are the 4 niches that develop?
1) Fissures
2) Approximal surfaces
3) smooth surface
4) gingival-tooth surfaces
Note: This allows dental plaque biofilm to first form
Plaque bacteria must be able to _______ very well to the __________.
- adhere
- tooth surface
(they must not be washed away by saliva, or food & drink)
Some bacteria like _______ finally find a place wehre they can colonize and compete well with the appearance of the deep pits & fissures of the 2nd molars.
-Strep mutans
With the eruption of the 2nd molars, the dental plaque ecology becomes relatively _______
-stable
What is the window of step. mutans infectivity for 2nd molars?
19-33 months
