perio immunology Flashcards
gingivitis vs periodontitis
Inflammation localised to the gingival tissues and Normal physiological response to infection or injury
Inflammation of the gingival tissues and supporting structure (PDL and alveolar bone) and Pathological inflammatory response associated with tissue destruction that does not resolve
hallmark sign of periodontitis
attachment loss
alveolar bone loss
what are the immune defences in our oral cavity?
GCF, oral mucosa barrier, saliva
how does saliva serve its immune purpose
has antimicrobial peptides and proteins
but it cannot remove accumulated biofilm, requires mechnical brushing
how does oral mucosa protect the oral environment
physical barrier preventing microbes from entering
functional barrier that expresses TLR that detect PAMPs
epithelial cells on oral mucosa release cytokines, chemokines and antimicrobial peptides. These signals recruit immune cells into the gingival tissues
igg and iga function in the mouth
IgG => bind to pathogen and triggers immune reaction
IgA => coat and prevent binding of pathogens to tooth surfaces
aetiological factors of periodontal diseases
- Accumulated plaque bacteria from poor OH
- Presence of periodontal pathogens (orange red complex)
- Polymicrobial dysbiosis
- In susceptible hosts (immune system plays a role)
- Host-pathogen interactions determine susceptibility
what types of bacteria are present in perio patients
Red complex
- Porphyromonas gingivalis
- Tannerella forsythia
- Treponema denticola
late colonizers
o gram negative anaerobic
o or facultative ie can survive with or without oxygen, uses up oxygen and breeds more anaerobes
what factors shape the composition of oral microbiome?
by interactions with the host (genetics, diet, lifestyle, behaviours)
virulence factors of P. gingivalis
o Immune evasion
o Asaccharolytic - nutrients from breakdown of proteins and peptides
o Gingipains - proteases with broad-specificity
o Atypical LPS –TLR4 antagonist - P.gingivalis can change its LPS, blocks signalling
o Inflammatory environment favours expression of virulence
o Drives dysbiosis in susceptible hosts
o factors simultaneously activate and subvert immune responses – thrive in inflammatory environments.
where are red complex bacteria most commonly found
areas of pocket depth and bleeding on probing
What is Polymicrobial dysbiosis
community of pathogens, work together to actively disrupt the normal homeostatic balance in the oral cavity for their own benefit
perio pathogens thrive in inflammatory conditions , changing the biofilm composition – healthy species are lost and disease-causing species thrive – this is polymicrobial dysbiosis.
what occurs in gingivitis
altered microbial colonisation
increased flow of GCF
influx of neutrophils
monocytes and lymphocytes
Increased TLR stimulation
Increased production of pro-inflammatory mediators
- Increased vasodilation
- Redness, swelling, bleeding
- Increased immune cell migration
what are gingipains
protein produced by P.gingivalis that mediates the interaction between P. gingivalis bacteria and hosts
what is the role of neutrophils in periodontitis? what happens when there is too much or too little neutrophils?
crucial for maintaining healthy periodontium
too little neutrophils => immune under reaction => leukocyte adhesion deficiency
too many neutrophils => immune over reaction and chronic inflammation
