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Questions and Answers
What is periodontitis?
What is periodontitis?
What defines a plaque biofilm?
What defines a plaque biofilm?
Which of the following best characterizes the host defense in the oral cavity?
Which of the following best characterizes the host defense in the oral cavity?
Which bacteria are typically associated with the pathogenesis of periodontal disease?
Which bacteria are typically associated with the pathogenesis of periodontal disease?
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What role do cytokines play in the host response?
What role do cytokines play in the host response?
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What are matrix metalloproteinases (MMPs) primarily involved in?
What are matrix metalloproteinases (MMPs) primarily involved in?
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What basic factors may contribute to the initiation of periodontitis?
What basic factors may contribute to the initiation of periodontitis?
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What is a key feature of the periodontal ligament's response to microbial infection?
What is a key feature of the periodontal ligament's response to microbial infection?
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What transformation occurs in the junctional epithelium that compromises its protective function?
What transformation occurs in the junctional epithelium that compromises its protective function?
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Which cells are responsible for secreting cytokines and Tumour Necrosis Factor in gingival tissues?
Which cells are responsible for secreting cytokines and Tumour Necrosis Factor in gingival tissues?
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What is one of the primary roles of saliva in the oral cavity?
What is one of the primary roles of saliva in the oral cavity?
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What term is used to describe the immune response that is specific to particular pathogens?
What term is used to describe the immune response that is specific to particular pathogens?
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Which mechanism does the humoral immune response utilize?
Which mechanism does the humoral immune response utilize?
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What is the fourth stage of dental plaque biofilm formation?
What is the fourth stage of dental plaque biofilm formation?
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Which of the following is NOT a component of the intra-cellular matrix of dental plaque biofilm?
Which of the following is NOT a component of the intra-cellular matrix of dental plaque biofilm?
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What type of bacteria primarily supports the subgingival environment?
What type of bacteria primarily supports the subgingival environment?
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Which of the following parts of the gingival epithelium covers the free and attached gingivae?
Which of the following parts of the gingival epithelium covers the free and attached gingivae?
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Which bacterial species is known for producing gingipains to utilize GCF as a nutrient source?
Which bacterial species is known for producing gingipains to utilize GCF as a nutrient source?
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What describes the junctional epithelium within the gingival epithelium?
What describes the junctional epithelium within the gingival epithelium?
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What is one function of the carbohydrate capsule produced by Porphyromonas gingivalis?
What is one function of the carbohydrate capsule produced by Porphyromonas gingivalis?
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Calcium is part of which category in the composition of dental plaque biofilm?
Calcium is part of which category in the composition of dental plaque biofilm?
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What type of immune response is initiated by plaque in the first instance?
What type of immune response is initiated by plaque in the first instance?
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Which component forms as a result of acute inflammation and has a function in flushing out microorganisms?
Which component forms as a result of acute inflammation and has a function in flushing out microorganisms?
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What role do PMNs play in the cellular response during the initial immune defense?
What role do PMNs play in the cellular response during the initial immune defense?
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Which species has a leukotoxin that can kill white blood cells?
Which species has a leukotoxin that can kill white blood cells?
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What mechanism does Treponema denticola use to disrupt host defenses?
What mechanism does Treponema denticola use to disrupt host defenses?
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How does the epithelium defend against plaque microorganisms?
How does the epithelium defend against plaque microorganisms?
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What is a significant outcome of the presence of Tannerella forsythia in the oral cavity?
What is a significant outcome of the presence of Tannerella forsythia in the oral cavity?
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Which of the following substances are found in GCF that help defend against microorganisms?
Which of the following substances are found in GCF that help defend against microorganisms?
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What is the primary action of pro-inflammatory cytokines during periodontitis?
What is the primary action of pro-inflammatory cytokines during periodontitis?
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Which cytokines are classified as anti-inflammatory?
Which cytokines are classified as anti-inflammatory?
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What factor disturbs the dynamic equilibrium in periodontal health?
What factor disturbs the dynamic equilibrium in periodontal health?
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Which of the following is a proposed issue with the Non-specific Plaque Hypothesis?
Which of the following is a proposed issue with the Non-specific Plaque Hypothesis?
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What is one role of prostaglandins, like PGE_2, in periodontal disease?
What is one role of prostaglandins, like PGE_2, in periodontal disease?
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What do matrix metalloproteinases (MMPs) primarily do in the context of periodontitis?
What do matrix metalloproteinases (MMPs) primarily do in the context of periodontitis?
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Which factor does NOT contribute to the initiation of periodontitis?
Which factor does NOT contribute to the initiation of periodontitis?
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What is the key characteristic of the Specific Plaque Hypothesis?
What is the key characteristic of the Specific Plaque Hypothesis?
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Study Notes
Periodontitis
- Periodontitis is a bacterial infection that triggers an inflammatory response in the periodontium, leading to irreversible damage of the periodontal ligament and alveolar bone.
Dental Plaque Biofilm
- Plaque biofilm is a community of microorganisms embedded in a glycocalyx on teeth surfaces.
- Plaque biofilm is composed of organic and inorganic components:
- Organic: polysaccharides, proteins, glycoproteins, lipids
- Inorganic: calcium, sodium, phosphorous, potassium
- Formation of plaque biofilm occurs in four stages:
- Initial attachment of bacteria to pellicle
- Initial colonization of the tooth surface
- Secondary colonization with extracellular slime layer formation
- Mature biofilm with mushroom-shaped colonies
Tissues of the Periodontium
-
Gingival epithelium:
- Oral epithelium: covers free and attached gingiva
- Sulcular epithelium: lines the gingival sulcus
- Junctional epithelium: at the base of the sulcus
- Other periodontal tissues include:
- Periodontal ligament
- Root cementum
- Alveolar bone
Bacteria Associated with Periodontal Disease
- Subgingival environment favors anaerobic bacteria.
- Common bacteria associated with periodontal disease include:
- Porphyromonas gingivalis
- Aggregatibacter actinomycetemcomitans
- Treponema denticola
- Tannerella forsythia
- Fusobacterium nucleatum
- Prevotella intermedia
- Virulence factors enable bacteria to:
- Colonize the periodontium
- Invade tissues
- Damage periodontal structures
-
P. gingivalis:
- Produces gingipains to utilize gingival crevicular fluid
- Contains LPS, haemagglutinins, and platelet aggregators
- Possesses fimbriae for tissue invasion
- Can suppress early polymorphonuclear leukocyte response
- Tannerella forsythia: Produces proteases and an apoptotic-inducing factor
-
Treponema denticola:
- Adheres to fibroblasts
- Invade tissues
- Disrupt host defense by manipulating cytokines
- Delay wound healing
-
A. actinomycetemcomitans:
- Produces leukotoxin, destroying white blood cells
- Possesses toxins that damage fibroblasts and epithelial cells
- Produces proteases, including collagenase
- Can invade epithelial cells
Host Defenses in the Oral Cavity
-
Innate Immune Response:
- Saliva: Contains antimicrobial factors and aids in swallowing bacteria
- Epithelium: Provides a physical barrier against bacteria
-
Inflammatory Response:
- Fluid Component: GCF forms as a result of inflammation and washes out microorganisms
- Cellular response: Primarily PMNs like neutrophils and macrophages attack and remove microorganisms
-
Adaptive Immune Response:
- Activated when innate immunity fails to eliminate pathogens
- Highly specific to individual pathogens
- Uses humoral and cell-mediated immunity:
- Humoral immunity: involves antibody production
- Cell-mediated immunity: involves T-cells
Cytokines, Prostaglandins, and MMPs
-
Cytokines:
- Pro-inflammatory: IL-1, IL-6, TNF-α, contribute to tissue destruction
- Anti-inflammatory: IL-4, IL-10, reduce inflammation
-
Prostaglandins (e.g. PGE2):
- Promote bone resorption
- Induce neutrophil chemotaxis
- Increase vascular permeability and dilation
-
Matrix Metalloproteinases (MMPs):
- Degrade connective tissue, contributing to tissue destruction
Factors Contributing to Periodontitis Initiation
- Disturbance of the equilibrium between dental plaque and host defenses favor tissue damage.
- Contributing factors include:
- Increased plaque accumulation
- Increased pathogenicity of microorganisms in the biofilm
- Compromised host defenses
Theories on the Role of Bacteria in Periodontitis
-
Non-specific Plaque Hypothesis:
- Plaque biofilm accumulation leads to inflammation and tissue destruction.
- Issues: Simplistic, does not explain all cases, does not account for specific pathogenicity.
-
Specific Plaque Hypothesis:
- Specific bacteria, rather than total plaque amount, cause periodontal disease.
- Supporting evidence: Identification of specific periodontal pathogens and their virulence factors.
-
Keystone Pathogen-Host Response Hypothesis:
- Specific ("keystone") pathogens disrupt the microbiome, leading to a dysbiotic state and enhanced inflammatory response.
- Issues: Identifying specific keystone pathogens remains challenging.
- Supporting evidence: Microbiome studies demonstrating changes in bacterial populations and inflammatory responses in periodontitis.
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Description
Test your knowledge on periodontitis, dental plaque biofilm, and the tissues of the periodontium. This quiz covers essential topics, including the stages of biofilm formation and the structure of gingival epithelium. Get ready to dive deep into periodontal health!
