CSA microbiology of caries Flashcards
(46 cards)
how is caries multifactorial?
key oral microorganisms
susceptible host
enviro. factors
what are enviro. factors?
poor diet
poor oral hygiene
low saliva flow rate
what are cofounding factors for caries?
o Fluoride availability
o Diverse natural microbiota
o Non-specific virulence factors
evidence for caries as infectious disease?
- gnotobiotic animal studies
- Human epidemiology studies
What do gnotobiotic studies show?
cant get caries in absence of microorganisms
- showed transmission of caries and
- showed antimicrobial agents work against caries
what is human epidemiology studies?
cross or longitudinal studies
what is cross sec studies?
group of people and sample microorganisms on tooth of people with and w/o caries
What is longitudinal studeies?
- Get a cause relationship
- Microorganisms sampled before & after diagnosis of caries
what are the implicated microorganisms with caries?
Mutans streptococci
Actinomyces
lactobacalli
Bifidobacteria
what mutans streptococci are there?
Strep. Mutans
Strep. sobrinus
Strep. cricetus
Strep. rattus
What actinomyces are there?
A. naeslundii
A. odontolyticus
(A. israelii / A. gerencseriae)
What Lactobacilli are there?
Lactobacillus spp.
What bifidobacteria are there?
Bifidobacterium/ Scardovia spp
what are mutans strepto. ?
• Gram positive cocci that are round organisms
what does mutans streptococcie do?
- colonise hard surfaces such as dentures/teeth (non-shedding surfaces)
• initiate caries if enough of them
what happens if give mutans strep. sucrose?
make extracellular sticky polymers
What is lactobacillus?
Gram positive rod more associated with advanced lesions
Bifidobacterium?
• Gram positive rod that are branched cells
why is it hard to understand aetiology of caries
- Disease occurs at sites with natural diverse microbiota
• Pathogens can found at healthy sites but in small number
• difficult to correlate microorganisms to the status of the enamel
• Lesions can re-mineralise
• Pathogenic traits are relatively non-specific
• Caries is multi factorial
what is microbiological aetiology of caries?
- MS seen in higher proportion at carious sites
* inverse relationship between MS & S. Sanguinis
what does cross sec study of fissure caries show?
3/4 of carious fissure had >10% of MS
what does longitudinal study of fissure caries show?
- higher proportions of MS at caries sites
- MS can be after first signs of demineralisation
- Caries can be apparent in absence of MS
- Role of other species in caries progression
what is role of other bacteria?.
- Acidogenic/Low pH isolated & can survive acidic conditions:
- Lactate-utilising species
- Base generating species
what is childhood caries?
bottle to suck with sugar drink
