Microbiology of Caries

Question 1

What are the four key factors involved in caries progression?

what is the cycle they interact in?

Answer 1

Saliva, Diet, Microbiota, and Tooth.

These factors interact in a cycle of: Adhesion → Survival & growth → Biofilm formation → Complex plaque → Acid → Caries

Question 2

What are the key characteristics that make Streptococcus mutans considered an “arch villain” in caries?

Answer 2

• Glycolytic systems
• EPS/sucrose metabolism
• Attachment mechanisms (GTF, Ag I/II)
• Greater acidogenicity/aciduricity compared to competitor species
• Ecological competitiveness at low pH
• Specific genomic characteristics
• Clear link between S. mutans presence and caries
• Mutans strep proportions linked to high sugar diet

Question 3

To make a pathogen definitive to a disease:

kohs postules 4

Answer 3

• must be present in every case of the disease.
• You must be able to isolate it from the diseased host and grow it in pure culture
• The disease must be reproduced when a pure culture is introduced into a susceptible host
• The microbe must be recovered from an experimentally infected host

Question 4

What makes carbohydrates besides sucrose cariogenic?

Answer 4

Cooked starches (like crisps and biscuits) can be cariogenic
“Sticky in the hand = sticky in the mouth” principle
Food retentivity is crucial
Micro-analytical methods provide supporting evidence
Some starches can yield prolonged glucose challenge leading to lactic acid production

Question 5

What are examples of cariogenic bacteria?

Answer 5

• Streptococcus Mutans
• Lactobacillus
• Actinomyces