Dental Plaque and Biofilms (3) Flashcards
What type of plaque is hard to investigate?
subgingival plaque
What makes the subgingival environment different to the supragingival environment?
Protected from friction
Attachment and adherence is less important
Different nutrients available
Eh - Lower oxygen concentration (different redox potential
pH - alkaline
Different host defence mechanisms
What are the initial colonisers of subgingival plaque?
Gram –ve rods and cocci and Spirochaetes are the initial colonisers
more motile bacteria
What type of anaerobe does the more complex subgingival plaque consist of?
With time subgingival plaque becomes more complex and consists predominantly of obligatory or facultative anaerobes
When does subgingival plaque become established?
Subgingival plaque may become established as early as 4 weeks after the onset of gingivitis
How many bacteria are motile in the subgingival plaque?
50%
Why does the subgingival plaque have no or little matrix production?
it doesn’t have the frictional forces on it
therefore the bacteria are loosely adherent to the tooth surface
What fluid delivers the microbes to the subgingival area?
the GCF
gingival crevicular fluid
What does the GCF deliver?
Humoral and cellular defence factors
Proteins and glycoproteins that serve as novel substrates for microorganisms e.g. haem containing molecules
What cellular defence factors does the GCF provide?
neutrophils
WBC
What do glycoproteins act as to bacteria in the subgingival area?
act as food
When do haem containing molecules arise?
in inflammatory areas
lots of blood
What type of bacteria are associated with periodontal diseases?
asacchrolytic
What do asacchrolytic microbes feed on?
not sugars but proteins
proteolytic
How does proteolysis effect pH?
more alkaline environment
What bacteria does the more alkaline conditions favour in the subgingival pocket?
Porphyromonas gingivalis
(periodontal pathogens)
Does the temperature increase or decrease during inflammation?
increase
due to proteolytic metabolism
Compare the supra- and subgingival plaque with regards to their matrix
supra = 50% matrix
sub = little or no matrix
Compare the supra- and subgingival plaque with regards to their flora
supra = mostly Gram +ve rods and cocci
sub = mostly Gram -ve and spirochaetes
Compare the supra- and subgingival plaque with regards to their motile bacteria
supra = few
sub = common
Compare the supra- and subgingival plaque with regards to their aerobic/anaerobic bacteria
supra = aerobic unless thick
sub = anaerobic
Compare the supra- and subgingival plaque with regards to their metabolism
supra = mostly carbohydrate
sub = mostly protein
Compare the supra- and subgingival plaque with regards to their species diversity
supra = little but increasing with age
sub= great
