Host responses to oral biofilms Flashcards
How is periodontitis different to different health conditions?
Bacterial load is located generally “outside” the body making it a challenge for immune-inflammatory response to take action.
Plaque is a biofilm
Periodontitis is a result of dysbiosis of the normal microbiome
Where are biofilms located in periodontitis and gingivitis?
In gingivitis: Supragingivally
In periodontitis: Subgingivally
What risk factors tip the homeostasis towards dysbiosis? What factors favour resistance?
Resistance: Innate and adaptive immune response, inflammation, and other structural components.
Risk factors: Environmental factors such as smoking, dental plaque accumulation, socioeconomic status as well as host-specific factors such as genetic factors and overall inflammatory burden.
How does the epithelium provide a barrier to entry of microorganisms?
It forms a physical and biological barrier:
Physical barrier via turnover + peeling
Biological barrier via defensins, IL-8, adesion mols, and PMNs
How does GCF protect against inflammation?
Consists of plasma derived substances such as antibodies, cytokines and enzymes. Also composed of epithelium and immune cells.
GCF volume and flow increase with increasing inflammation.
What are the first defense cells against periodontitis?
Neutrophils
What innate immune system structures are protective?
Saliva: Prevents drying of gingiva and teeth with antimicrobial effects.
Epithelium: Physical barrier, inflammatory response via keratinocytes, and immune response via langerhans’ cells
Inflammatory response: Fluid component (GCF) and cellular components such as neutrophils and macrophages
What adaptive immune system structures are protective?
Humoral response
Cell-mediated response
What does LPS do to periodontium?
It stimulates macrophages to produce MMPs, IL-1b, and TNF-a
It stimulates fibroblasts to produce more MMPs
It stimulates IL-1b production as well as TNF-a by B cells and macrophages.
What are the histopathological classifications of clinical presentation of gingivitis?
Pristine: Histological perfection
Initial: Clinically healthy gingiva
Early: Early gingivitis
Established: Chronic or established gingivitis
Advanced: Periodontitis
What are the features of pristine gingiva?
Super healthy gingiva with no infiltrate
No bleeding
Pink, firm, scalloped outline, stippled and knife edge margin
Shallow gingival sulcus up to 3mm deep
Free of histological inflammation is extremely rare
What are the features of clinically healthy (not pristine) gingiva?
Healthy with infiltrate
Neutrophils and macrophages in JE
Lymphocytes in connective tissue
Collagen reduction not detectable clinically
Increase in vascular structures
Exudate and transudative fluid from vessels to tissues (GCF)
What does the initial lesion look like in periodontitis?
Change in microvascular plexus JE (vessels remain dilated and increase in number)
Arteriolas capillaries, and venules dilation
Hydrostatic pressure increase
Increased permeability
Exudate of fluids and proteins
Increased GCF
Enhanced PMNs migration
PMNs accumulate in JE and sulcus
VERY FEW PLASMA CELLS
What are the commonly seen features of ginigvitis?
10 to 20 days of plaque accumulation
Clinical signs of gingivitis
Redness, swelling, Blood on probing
Reversible after plaque removal
When does the early lesion from gingivitis form?
One week after plaque accumulation
