Microbiology of caries II Flashcards
what is postulates
when pathogens are a direct cause of disease
what are dental diseases an example of
dysbiosis of a beneficial resident microbiotia
- implications for oral care?
How does dysbiosis occur?
- Increase in cariogenic bacteria in biofilm
- MS, lactobacilli, bifidobactiera, scardovvia can produce and tolerate acid
- Homeostasis becomes disrupted and there is major ecological error - frequent consumption of sugar ,reduce salivary flow
- acidic PH – due to fruit possible
- persistency can shift bacterial population to dominate cariogenic species which tolerate acids
- produce intracellular polysaccharide
what is symbiosis and how does it work
where beneficial bacteria are more competitive under ‘ healthy’ oral conditions
beneficial bacteria thrive better in healthy levels
what are the 3 different hypotheses to explain transition form health to disease
specific plaque hypothesis - specific pahtogens
non specific plaque hypothesis - many species have role
Ecological plaque hypothesis
how is dental disease preventable;e/controllable
- direct inhibition of causative organisms
- promotion of natural balance
- interference with factors driving dysbiosis
what does the ecological plaque hypothesis describe
- Aetiology need not be mono specific
- carriage of pathogens - clinically insignificant levels
environmental regulation of general expression - disease preventable/controllable by
- direct inhibition of causative organisms
- maintenance of natural balance
-interference with factors driving deleterious shifts in microbiota - low ph in biofilm; sugar metabolism; low saliva flow
what occurs in a cariogenic diet environment?
increased sugar frequency
increased low PH challenges
MS,lacotbaclli,bifidobacteria
caries
what occurs in good oral hygiene
neutra; PH
s.SANGUINIS
S.gordonii
health
how does sugar play a role in dysbiosis
sticky slime- ECM polymers \fermentation products- acidic PH \sticky slime allows bacteria to adhere
how do we model oral microbiota
nutrients- fermentable surgas
oscillating ph - acidic/neutral
beneficial bacterial domina on mucin te growing
controlled PH at different levels
lfurodie added to prevent MS growth- it Works
what are the 7 approaches for controlling dental caries
- plaque control
-fluoride
-sugar substitues
-Antimcirobial and anti-plaque agents - modify the microbitoia
- vaccination
-passive immunisation
what the benefits of using fluoride to control dental caries
- fluroapatite
- de/remienralsiton
- acidify cell interior (H+F-)
- inhibit IPS synthesis
reduce glycolysis and acid production - remove competitive opportunity for MS and other acid- loving bacteria by eliminating a low PH enviroenmtn
how can sugar substitutes control dental caries
- bulking agents (eg. sorbitol, xylitol)
- intense sweeteners ( eg. saccharin,aspartame)
- not or weakly metabolised to a cid
-stimuate saliva flow
-weak antimicrobial activity (eg.xylitol and MS)
what are the difference between treatment of medical and dental diseases with antimcorbial agents
classical medical
- single pathogen
- sterile site
-absent form health
-bactericidal drugs preferred
Conventional dental
- mixed community/biofilm
-site with resident beneficial microbiota
-present in heath
-MIC or <MIC effective
what are the antimicrobial and anitplaque agents to control dental caries
- tooth pastes and mouthwash
- chlorhexidine= gold standard - antiplaque,anitmutans,MS
- triclosan,metal salts, plant extracts, enzymes
- add agents to generate alkali
MIC v sub MIC effects
anitmcirobial and anitplaque
