Periodontal Immunology

Question 1

Compare gingivitis to periodontitis (6)

Answer 1

GINGIVITIS

1. Inflammation localised to gingival tissues
2. Acute inflammation
3. Normal protective, physiological response to infection or injury

PERIODONTITIS

1. Inflammation of gingival tissues + supporting periodontal structures
2. Chronic inflammation
3. Pathological inflammatory response associated with tissue destruction

Question 2

What environmental factors trigger gingival inflammation?

Answer 2

1. Smoking
2. Age
3. Diabetes
4. Pregnancy (hormonal changes can make gums more vulnerable)

Question 3

What factors determine whether inflammation resolves or progresses?

Answer 3

Host-bacterial interactions

Question 4

Describe the term virulence factors

Answer 4

Factors that are produced by a microorganism and evoke disease

Question 5

Name examples of virulence factors (4)

Answer 5

1. Assaccharolytic
2. Gingipains
3. Atypical LPS
4. Inflammophilic

Question 6

Define what assacharolytic means

Answer 6

Nutrients from breakdown of proteins and peptides

Question 7

Define what gingipains are

Answer 7

Proteases with broad-specificity
> Degrade host proteins
> Activate MMPs

Question 8

What factors trigger gingival inflammation?

Answer 8

1. Changes in oral biofilm which can be due to
   > Accumulation
   > Composition
   > Expression of virulence

Question 9

Function of saliva

Answer 9

contains lots of enzymes + antimicrobial peptides and bicarbonate buffers that protect the integrity of teeth

Question 10

What is released in response to gingivitis? (6)

Answer 10

1. Increased TLR stimulation
2. Increased production of pro-inflammatory mediators
3. This triggers acute inflammatory response
4. Neutrophils remain the predominant cell type in lesion
5. Monocytes activated and differentiate into macrophages
6. Lymphocytes are recruited to fine tune immune response

Question 11

What does attachment loss indicate?

Answer 11

Evidence of true pocket formation

Question 12

What does an INCREASE in immune and inflammatory cells in the periodontist lead to?

Answer 12

Periodontitis

Question 13

Function of neutrophils in periodontal tissue destruction

Answer 13

No’s are increased during gingivitis:

> If they contain infection = return to health

> If they are unable to contain infection = predispose to disease progression

Question 14

What is an excessive infiltration of neutrophils associated with?

Answer 14

Chronic inflammation, excessive amounts contributes to tissue destruction

Question 15

What enzymes are involved with chronic inflammation

Answer 15

1. Degradative enzymes

2. Inflammatory cytokines and O2 radicals

Question 16

Describe the role of adaptive immunity in periodontal destruction (5)

Answer 16

1. T + B lymphocytes present in early lesion
2. CD4 T cells, B cells and dendritic cells present as lesion progresses
3. They are unable to regulate symbiotic biofilm
4. B cell/ plasma cells predominate advanced lesions
5. IgG fails to regulate dysbiotic biofilm

Question 17

What imbalance leads to bone loss?

Answer 17

An imbalance between bone resorption and bone formation

Question 18

Function of osteoblasts

Answer 18

Synthesise + secrete bone tissue (osteoid)

Question 19

Function of osteoclasts

Answer 19

Resorbs bone

> Derived from monocyte/macrophage lineage

Question 20

What regulates bone formation and bone resorption?

Answer 20

RANKL/RANK/OPG triad

Question 21

How does inflammation lead to bone loss?

Answer 21

1. Activated T/B cells in periodontal lesion secrete RANKL
2. RANKL binds to RANK to induce osteoclast differentiation
3. OPG prevents RANKL binding to RANK
4. This inhibits osteoclast differentiation and leads to alveolar bone resorption
5. Pro-inflammatory cytokines contribute to bone resorption by inhibiting bone formation by interacting with osteoclasts

Question 22

What does high levels of RANKL lead to?

Answer 22

Bone resorption

Question 23

What does low levels of OPG lead to?

Answer 23

Bone formation

Question 24

What microbe causes periodontitis?

Answer 24

P. gingivalis

Question 25

Compare: Colonisation (3) Infection (3)

Answer 25

COLONISATION 1. Microbial presence on a body surface without clinical sign of inflammation 2. Commensal = part of normal flora in the mouth 3. Commensal organisms can become pathogenic if conditions favour expression of virulence INFECTION 1. Microbial invasion of host tissues 2. Involves pathogens 3. Pathogens can behave like commensal if conditions do NOT favour the expression of virulence

Question 26

Name immune defences present in the oral cavity (3)

Answer 26

1. Gingival crevicular fluid - AMPS, Cytokines, IgG 2. Oral mucosa - AMPS, Cytokines, Chemokines 3. Saliva - S-IgA, Lysozyme, Histatins + Cystatins