Periodontal Immunology Flashcards
What is gingivitis
it is inflammation localized to gingival tissues
it is the normal physiological response to infection or injury
what type of inflammation is gingivitis
acute
what is periodontitis
inflammation of the gingival tissues and supporting periodontal structures
pathological inflammatory response associated with tissue destruction
what type of inflammation is periodontitis
chronic
is plaque (poor oral hygiene) an etiological factor of periodontitis
yes
but it isn’t the full picture
there are other factors that accelerate the disease
describe the oral biofilm composition
bacterial interactions modify the environment species
what are the late colonizers typically
the late colonizers are typically gram negative anaerobes
what are the early colonizers typically
and early colonizers are typically commensal
what are the microbes in the red complex
porphyromonas gingival
tannerella forsythia
treponema denticola
what is the red complex
these were detonated as periodontal pathogens as their numbers correlate with pocket depth and bleeding on proving.
do specific bacterial species cause periodontal disease?
periodontitis cannot occur in the absence of bacteria
it is difficult to establish the role of specific microbes
what are the features of the periodontal pathogens
they are present at low numbers in healthy sites
they have increased numbers in diseased sites
what is the difference between colonization and infection
colonization does not involve disease - bacteria are present but not actively trying to invade tissues
can commensals become pathogenic
yes if the opportunity arises
what is the first stage of infection
colonisation
what is the ability to cause disease based on
ability to cause disease is not an inherited trait, it is based on the outcome with the human immune system
what do microbes express
virulence factors and if there is up regulation to allow invasion the immune system will notice
what are the virulence factors of p. gingival
asaccharolytic
gingipains
atypical LPS
inflammophilic
what does asaccharolytic mean
cannot use carbohydrates as an energy source
needs proteins and peptides which it gets from host proteins
what are gingipains
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
what is atypical LPS
a TLR4 antagonist
what does inflammophilic mean
inflammatory environment favors expression of virulence
what factors trigger gingival inflammation
changes in oral biofilm:
accumulation
composition
expression of virulence
what factors determine whether inflammation resolves or progresses
periodontal pathogenesis is determined by host bacterial interactions
what are the immune defenses in the oral cavity
gingival crevicular fluid
oral mucosa
saliva
what are present in the oral mucosa that are protective
TLRs bind and recognize microorganisms and cells respond by releasing AMPs which trigger release of cytokines and chemokine
what is present in saliva that is protective
s-IgA lysozyme perioxidase lactoferrin mucins agglutins cystatins histamines
what is present in GCF that is protective
AMPs cytokines chemokines lactoferrin igG
what is the predominant cell in gingivitis
neutrophils
what do monocytes do in gingivitis
they move into tissue, activated by cytokines and bacterial components and differentiate into macrophages
what do lymphocytes do
they are present and they fine tune responses at this stage
describes what happens in gingivitis
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)
what is the role of neutrophils in periodontal tissue destruction
it is crucial for maintaining healthy periodontium
numbers increase during gingivitis
excessive infiltration associated with chronic inflammation
what happens in an immune under reaction
there is aggressive periodontitis with leukocyte adhesion deficiency
what happens in immune over reaction
adult chronic periodontitis
why is excessive infiltration of neutrophils associated with chronic inflammation
degradative enzymes (major source of MMPs) inflammatory cytokines and oxygen radicals contribute to hypoxic environment connective tissue destruction manifests clinically as loss of attachment
what is the role of adaptive immunity in periodontal destruction
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
how is the role of adaptive immunity in periodontal destruction protective
it prevents systemic infection
how is the role of adaptive immunity in periodontal destruction destructive
inflammation induced alveolar bone loss
how does inflammation lead to bone loss
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
describe the cellular an molecular events linking bacterial induced inflammation with pathological tissue destruction
- periodontal pathogens releasing bacterial products which activate TLR on oral epithelium cells and fibroblasts and they respond by releasing chemokine and cytokines
- vasodilation and recruitment of cells from the blood, swelling, redness
- neutrophils move into tissues and are activated by bacterial products and they also release cytokines so there is amplification within tissues
- lymphocyte recruited, they express rank and disrupt homeostatic relationship between OPG and RANKL
- osteoclastogenesis that leads alveolar bone resorption
- pro inflammatory cytokines can interact with osteoblasts which inhibit bone formation so contribute to bone destruction
- MMPs come from excessive neutrophils present and help degrade the ECM leading to loss of attachment
