Microbiology - Periodontal Disease

Question 1

name the classifications of periodontal disease. (4)

Answer 1

Gingivitis

Periodontitis – chronic or aggressive

Necrotising

Per-implantitis

Question 2

What changes to host factors can increase the pathological environment and cause periodontitis? (6)

Answer 2

• Poor dietary changes
• Reduced salivary flow
• Smoking and tobacco use
• Medications
• Hormonal changes e.g. in pregnancy and disease
• Systemic diseases e.g. diabetes and CV disease

Question 3

what organisms are found at the surface of a periodontal pocket?

Answer 3

gram positive aerobic cocci

Question 4

what organisms are found at the base of a periodontal pocket?

Answer 4

gram negative anaerobes

Question 5

what do gram negative anaerobes release that cause bone to be resorbed? (3)

Answer 5

cytotoxin
proteinase
LPS

Question 6

what organisms are present in a healthy periodontium? (5)

Answer 6

• Oral streptococci
• Actinomyces
• Veillonella
• Haemophilus
• Fusobacterium

Question 7

what organisms are present in gingivitis? (5)

Answer 7

• Actinomyces
• bacteroides
• Prevotella intermedia
• Fusobacterium
• nucleatum

Question 8

According to the Red area on the Socransky’s chart, what organisms are present in periodontitis? (3)

Answer 8

• Porphyromonas gingivalis (keystone pathogen)
• T.forsythia
• T. denticola

Question 9

name two ways in which microbes can interact - describe these mechanisms.

Answer 9

Competition via production of harmful metabolic products such as acids and oxides

Or

Co-operation via production of helpful metabolic products such as saccharides, peptides and growth factors, production of adhesion substrates and allowing immune avoidance = co-infection

Question 10

list the virulence factors of p.gingivalis. (4)

Answer 10

• Fimbrae = attachment
• Releases proteolytic enzymes e.g. collagenase, phosphatases, fibrinolysin
• releases endotoxin which is pro-inflammatory
• Releases metabolic by-products e.g. ammonia and fatty acids

Question 11

how does p.gingivalis adhere?

Answer 11

Via fimbrae

• Long (FimA)
• Short (Mfa1)

Question 12

describe what gingipans are.

Answer 12

Arginine and lysine specific organisms

= provide own nutrition via heme

Question 13

According to the Amber/yellow area on the Socransky’s chart, what organisms are present in periodontitis? (3)

Answer 13

P. intermedia
C.rectus
F.nucleatum

Question 14

list virulence factors of periodontal pathogens. (4)

Answer 14

releases endotoxin

has outer membrane vesicles and capsular polysaccharides

attaches and invades via fimbrae

releases a cocktail of degrading enzymes - phosphotases and fibrinolysis