Microbiology Of Caries Flashcards
What were Millers major conclusions to his theory?
Dental caries was caused by multiple species of oral bacteria
Non-specific plaque hypothesis
Proper prevention techniques remove bacterial species
What is caries?
A biofilm dependent disease, bacterial in origin, causing demineralisation and deconstruction of hard tissues of the teeth. Result of production of acid by the bacterial fermentation of food debris accumulated on the tooth surface.
What happens if demineralisation exceeds saliva and other remineralisation factors?
Hard tissues progressively break down producing dental caries
Ethology of caries - what are the 4 factors that must act simultaneously for caries to occur?
Microorganisms in the plaque (bacteria)
Substrate/diet - intake of fermentable carbohydrates
Time and oral hygiene
Host factors e.g., tooth and saliva
What are the main bacteria associated with caries?
Mutans Streptococci, Lactobacilli, Actinomyces viscosus
When do streptococci mutans enter da mouth?
They possess adherence activity so can stick to the tooth surface after eruption.
Factors of strep mutans
Produce higher amounts of acids from sugars than other bacterial types and possess a high acid tolerance
Produce extracellular polysaccharides from sucrose
Factors of lactobacilli
Particularly in dentine and root varies
Acidogenic and acid tolerant
What can sugar metabolism by cariogenic bacteria do?
Formation of extracellular polysaccharides
Increases thickness of plaque
Gel limits movement of some ions and protects the plaque biofilm from salivary buffering
Can S mutans metabolise a wider variety of carbohydrates than other gram positive microorganisms?
Yes
Virulence factors of S mutans
Production of acid
Adhesins
Adherence mechanism
What is the sucrose independent attachment method of S mutans?
Bacteria can adhere to salivary agglutination glycoprotein
Adhere to other bacteria, the ECM and epithelial cell surface reveptors
What is the sucrose dependent method of attachment of S mutans?
Adhere to tooth surface by synthesising glucans by glucosyltransferases
Glucan promotes cell-cell aggregation by interacting with surface-associated glucan binding protein
What is replacement therapy of a bacterial disease?
Replacing a specific bacterial pathogens with a non-pathogenic strain, an effector strain
What factors should an effector strain have?
Should not cause disease
Must persistently colonise host tissue at risk and prevent outgrowth of the pathogen
Possess a high degree of genetic stability
