Periodontal Immunology

Question 1

What is gingivitis

Answer 1

it is inflammation localized to gingival tissues

it is the normal physiological response to infection or injury

Question 2

what type of inflammation is gingivitis

Answer 2

acute

Question 3

what is periodontitis

Answer 3

inflammation of the gingival tissues and supporting periodontal structures
pathological inflammatory response associated with tissue destruction

Question 4

what type of inflammation is periodontitis

Answer 4

chronic

Question 5

is plaque (poor oral hygiene) an etiological factor of periodontitis

Answer 5

yes
but it isn’t the full picture
there are other factors that accelerate the disease

Question 6

describe the oral biofilm composition

Answer 6

bacterial interactions modify the environment species

Question 7

what are the late colonizers typically

Answer 7

the late colonizers are typically gram negative anaerobes

Question 8

what are the early colonizers typically

Answer 8

and early colonizers are typically commensal

Question 9

what are the microbes in the red complex

Answer 9

porphyromonas gingival
tannerella forsythia
treponema denticola

Question 10

what is the red complex

Answer 10

these were detonated as periodontal pathogens as their numbers correlate with pocket depth and bleeding on proving.

Question 11

do specific bacterial species cause periodontal disease?

Answer 11

periodontitis cannot occur in the absence of bacteria

it is difficult to establish the role of specific microbes

Question 12

what are the features of the periodontal pathogens

Answer 12

they are present at low numbers in healthy sites

they have increased numbers in diseased sites

Question 13

what is the difference between colonization and infection

Answer 13

colonization does not involve disease - bacteria are present but not actively trying to invade tissues

Question 14

can commensals become pathogenic

Answer 14

yes if the opportunity arises

Question 15

what is the first stage of infection

Answer 15

colonisation

Question 16

what is the ability to cause disease based on

Answer 16

ability to cause disease is not an inherited trait, it is based on the outcome with the human immune system

Question 17

what do microbes express

Answer 17

virulence factors and if there is up regulation to allow invasion the immune system will notice

Question 18

what are the virulence factors of p. gingival

Answer 18

asaccharolytic
gingipains
atypical LPS
inflammophilic

Question 19

what does asaccharolytic mean

Answer 19

cannot use carbohydrates as an energy source

needs proteins and peptides which it gets from host proteins

Question 20

what are gingipains

Answer 20

enzymes
they are proteases which can cleave host proteins and make them available for that bacteria to use as nutrients. they can also activate MMPs

Question 21

what is atypical LPS

Answer 21

a TLR4 antagonist

Question 22

what does inflammophilic mean

Answer 22

inflammatory environment favors expression of virulence

Question 23

what factors trigger gingival inflammation

Answer 23

changes in oral biofilm:
accumulation
composition
expression of virulence

Question 24

what factors determine whether inflammation resolves or progresses

Answer 24

periodontal pathogenesis is determined by host bacterial interactions

Question 25

what are the immune defenses in the oral cavity

Answer 25

gingival crevicular fluid oral mucosa saliva

Question 26

what are present in the oral mucosa that are protective

Answer 26

TLRs bind and recognize microorganisms and cells respond by releasing AMPs which trigger release of cytokines and chemokine

Question 27

what is present in saliva that is protective

Answer 27

``` s-IgA lysozyme perioxidase lactoferrin mucins agglutins cystatins histamines ```

Question 28

what is present in GCF that is protective

Answer 28

``` AMPs cytokines chemokines lactoferrin igG ```

Question 29

what is the predominant cell in gingivitis

Answer 29

neutrophils

Question 30

what do monocytes do in gingivitis

Answer 30

they move into tissue, activated by cytokines and bacterial components and differentiate into macrophages

Question 31

what do lymphocytes do

Answer 31

they are present and they fine tune responses at this stage

Question 32

describes what happens in gingivitis

Answer 32

increased TLR stimulation increased production of pro inflammatory mediators triggers actue inflammatory response neutrophils remain the predominant cell type in the initial lesion monocytes are recruited (macrophages) lymphocytes are recruited (fine tune the immune response)

Question 33

what is the role of neutrophils in periodontal tissue destruction

Answer 33

it is crucial for maintaining healthy periodontium numbers increase during gingivitis excessive infiltration associated with chronic inflammation

Question 34

what happens in an immune under reaction

Answer 34

there is aggressive periodontitis with leukocyte adhesion deficiency

Question 35

what happens in immune over reaction

Answer 35

adult chronic periodontitis

Question 36

why is excessive infiltration of neutrophils associated with chronic inflammation

Answer 36

``` degradative enzymes (major source of MMPs) inflammatory cytokines and oxygen radicals contribute to hypoxic environment connective tissue destruction manifests clinically as loss of attachment ```

Question 37

what is the role of adaptive immunity in periodontal destruction

Answer 37

T and B lymphocytes present in the early lesion aggregates rich in CD4 T cells B cells and dendritic cells evident as lesion progresses unable to regulate dysbiotic biofilm b cell/plasma cells predominate advanced lesions IgG fails to regulate dysbiotic biofilm

Question 38

how is the role of adaptive immunity in periodontal destruction protective

Answer 38

it prevents systemic infection

Question 39

how is the role of adaptive immunity in periodontal destruction destructive

Answer 39

inflammation induced alveolar bone loss

Question 40

how does inflammation lead to bone loss

Answer 40

activated t and b cells in the periodontal lesion secrete RANKL RANKL binds RANK to induce osteoclast differentiation OPG prevents RANKL binding RANK OPG inhibits osteoclast differentiation

Question 41

describe the cellular an molecular events linking bacterial induced inflammation with pathological tissue destruction

Answer 41

1. periodontal pathogens releasing bacterial products which activate TLR on oral epithelium cells and fibroblasts and they respond by releasing chemokine and cytokines 2. vasodilation and recruitment of cells from the blood, swelling, redness 3. neutrophils move into tissues and are activated by bacterial products and they also release cytokines so there is amplification within tissues 4. lymphocyte recruited, they express rank and disrupt homeostatic relationship between OPG and RANKL 5. osteoclastogenesis that leads alveolar bone resorption 6. pro inflammatory cytokines can interact with osteoblasts which inhibit bone formation so contribute to bone destruction 7. MMPs come from excessive neutrophils present and help degrade the ECM leading to loss of attachment