Aetiology of periodontal disease: dental biofilm

Question 1

What is the definition of periodontal disease?

Answer 1

Bacterially-induced (infections), immune-mediated (host immune response involved) inflammatory diseases of the tissues supporting the teeth

Question 2

How would you describe the immune response of a healthy periodontal site?

Answer 2

Well defined, precisely orchestrated, effective immune response

Question 3

How would you describe the immune response of a diseased periodontal site?

Answer 3

Exacerbated, uncontrolled, detrimental immune response

Question 4

What is the definition of inflammation?

Answer 4

Protective tissue response to irritation, injury or infection.

It serves to destroy, dilute or wall off both the injurious agent and injured tissues.

Question 5

What are the classical signs of acute inflammation? (5)

Answer 5

Pain (dolor)

Heat (calor)

Redness (rubor)

Swelling (tumour)

Loss of function

Question 6

What is the primary aetiological factor for periodontitis?

Answer 6

Dental plaque

Question 7

What are the local aetiological factors for periodontitis?

Answer 7

Calculus, restorations with overhanging margins

These promote accumulation of dental plaque

Question 8

What are the systemic aetiological factors for periodontitis?

Answer 8

Diabetes mellitus, puberty, pregnancy, immunodeficiency

These modify the host-bacteria interaction

Question 9

What are the 3 prerequisites for periodontal disease?

Answer 9

Virulent periodontal pathogens

Local environment

Host susceptibility (smoking, diabetes, immunosuppression etc)

Question 10

What characteristics make the mouth a good habitat for microbial growth?

Answer 10

• Mucosal surfaces
• Hard, non-shedding tooth surfaces, dentures: supragingival and subgingival (lower oxygen tension, gingival crevicular fluid)
• Factors affecting growth of microorganismos: different nutrients etc

Question 11

Name the 5 resident microorganism in the mouth

Answer 11

bacteria (e.g. streptococci)

Fungi

Mycoplasma

Viruses (HSV-1, HPV)

Protozoa (trichomonas)

Question 12

What is the definition of dental plaque?

Answer 12

Complex microbial community that develops on the tooth surface (and other hard, non-shedding materials), embedded in a matrix of polymers of bacterial and salivary origin

Question 13

What do you call calcified plaque?

Answer 13

Calculus

or tartar

Question 14

Why do bacteria prefer to grow in a biofilm?

Answer 14

Because the collective strength and protection of the community in terms of survival is much greater than the sum of the components

Question 15

What are the 5 characteristics of dental plaque found supragingivally?

Answer 15

Nutrients are from the diet or saliva.

Carbohydrates are the primary energy source.

They are firmly adhered.

Higher oxygen tension.

Aerobes

Question 16

What are the 5 characteristics of dental plaque found subgingivally?

Answer 16

Nutrients are from the GCF (gingival crevicular fluid)

Proteins are their energy source

Many motile forms

Reduced redox potential - lower oxygen tension

Anaerobes