microbial aetiology of caries :) Flashcards
what is caries
multifactoral process of tooth demineralisation and remineralisation
what is incipident caries
white spot leisons (local area of enamel demineralisation)
what does caries result in
dissolution of apatit crystals in dentine and loss of calcium phosphate ect
caries is not..
a transmissible disease
what factors are requried for caires
susceptible tooth
oral bacteria
dietary carbohydrate
what bacteria are prevalent in caries
mutans and lacto bacillus
what bactierai is the most cariogenic
mutans streptocicci
when do people aqquire mutans streptococci
time of molars (12-30mnths)
if children do not aquire mutans during eruption they will wait till next window of infectivity
properties of mutans streptococci
sugar transport
acid production
aciduricity (ie can grow at low pH levels)
extracellular polysaccahirde production(contributes to plaque matri)
intracellular polysaccharide production
what thearapy is likely to be successful in removing cavitties
aimed at several types of organisms
what leads to caries
change in population composition of plaque
historicla theoires of cariogenesis
acidogenic
- acid produced by fermentation of carbohydrate demineralised enamel
proteolytic
- degredation of enamel matrix by bacterial proteases
hypotheses for microbial aetiology
specific ie only key organisms in plaque have metabolism that causes caries
non specific ie any plauw given fermentable carbohydtrae can give rise to caires
ecological
- combined abve ie environment within plaque determines disease
how can plaque change to being carious
dental plaque forms normally on teeth (benefits host by preventing colonization by exogenous species)
microbial homeostasis can break dow
subgingival microflora shifts from gram+ to gram -
slection of organisms with aciduric physiology more likely to survive
