Microbiology - Caries

Question 1

what factors do we need for caries? (4)

Answer 1

Tooth
Saliva
Bacteria
diet

Question 2

at what pH does demineralisation occur?

Answer 2

< 5.5

Question 3

what virulence factors does strep mutans possess? (6)

Answer 3

Produces lot of the EPS

Has the ability to adhere to teeth via antigens and adhesins

Can rapidly metabolise sugars

Creates an acidic environment which negatively affects other species within the mouth (out competes them)

Has the ability to modulate it’s behaviour (genetic modulation)

can initiate and maintain microbial growth in acidic conditions

Question 4

what foods are cariogenic? (2)

Answer 4

fermentable carbohydrates

Cooked starches – crisps, biscuits, had pretzels

Question 5

why are cooked starches possibly more cariogenic that other foods? (2)

Answer 5

they slowly leach fermentable carbohydrates over time.

they can also interact with sucrose

Question 6

name the microorganisms associated with caries? (4)

Answer 6

S mutans
Lactobacillus acidophilus
prevotella
actinomyces

Question 7

what virulence factors allow caries bacteria to adhere and survive in acidic conditions? (2)

Answer 7

altering membranes to monounsaturated lipids

up regulating DNA repair