CAP 5

Question 1

What is planktonic growth?

Answer 1

Single bacteria
Classic growth phase (lag, exponential, stationary decline)
Limited contact

Question 2

Transformation fro planktonic growth to a biofilm is a developmental pathway.

Answer 2

YES

Question 3

What is a biofilm?

Answer 3

Microbial communities attached to surface (complex aggregation of bacterium)

Question 4

Properties of a biofilm (6)

Answer 4

Spatially organised in a 3D structure
Bacterial cells enclosed in extra cellular matrix
Increases habitat range of bacteria
Extends habitat range (increases ability to survive)
Cells have switched from planktonic growth
Matrix= Extracellular Polymeric Substances

Question 5

Developmental stages of biofilm (5)

Answer 5

Pellicle formation
Attachment of individual bacterial cells
Growth of individual bacteria
Microbial succession and diversification
climax community

Question 6

What is Quorum Sensing?

Answer 6

The process in which single cells organisms monitor their population density by detecting the concentration of small molecules produced by themselves.

Question 7

What is the specific plaque hypothesis?

Answer 7

Caries down to a limited number of bacteria

Question 8

What is the non–specific plaque hypothesis?

Answer 8

Caries outcome of overall activity of microbes

Question 9

What is the ecological plaque hypothesis? (4)

Answer 9

Caries- high or frequent sugar intake favours acidogenic/aciduric bacteria
No specific mix of microorganisms
There are occasional but regular findings of caries with no mutans strepococci
The structure of the biofilm and location of MS varies

Question 10

What are caries prevention strategies? (6)

Answer 10

OHI, Diet, Fissure sealing (excluding carbohydrates adhering to biofilm), Fluoride, Control of biofilm pH (Use sigar substitutes, use antimicrobial agents (CHX), use fluoride), Novel strategies (use vaccinations)