Microbiology of Periodontal Disease Quiz (ODS Learning Outcomes)

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Questions and Answers

Which of the following bacteria is NOT a periodontal pathogen?

Porphyromonas gingivalis

Tannerella forsythia

Treponema denticola

Streptococcus mutans (correct)

What is the role of gingipains produced by Porphyromonas gingivalis?

To degrade host cell DNA

To enhance the immune response

To digest tissue proteins and destroy host defenses (correct)

To disrupt carbohydrate metabolism

Which virulence factor is associated with Tannerella forsythia?

Apoptotic-inducing factor (correct)

Lipid A

Fimbrae

Haemagglutination

What type of microorganisms are predominantly found in the supragingival plaque?

Gram-positive aerobes Signup and view all the answers

What is the function of the extracellular slime layer in dental plaque?

To provide a protective barrier and channels for fluid Signup and view all the answers

Which of the following factors helps Treponema denticola in tissue invasion?

Motility and adherence factors Signup and view all the answers

Which Gram-negative organism produces endotoxins that can affect host defenses?

Porphyromonas gingivalis Signup and view all the answers

What is the potential consequence of haemagglutination by Porphyromonas gingivalis?

Increased risk of cardiac issues Signup and view all the answers

The transition from gingival health to periodontal disease often involves which of the following changes?

Overgrowth of specific Gram-negative pathogens Signup and view all the answers

Which of the following statements about periodontal disease pathogens is correct?

They can all invade host tissues and produce virulence factors. Signup and view all the answers

What type of organism is Aggregatibacter actinomycetemcomitans?

Gram-negative coccoid bacillus Signup and view all the answers

What is one of the virulence factors produced by Aggregatibacter actinomycetemcomitans?

Leukotoxin Signup and view all the answers

Which type of periodontal disease is Aggregatibacter actinomycetemcomitans primarily associated with?

Aggressive periodontitis Signup and view all the answers

Which of the following statements is NOT true about Aggregatibacter actinomycetemcomitans?

It is motile. Signup and view all the answers

Which environmental factor is linked to the aetiology of periodontal disease?

Poor oral hygiene Signup and view all the answers

In the context of periodontal disease, what do PMN defects refer to?

Defects in polymorphonuclear leukocytes Signup and view all the answers

How does Aggregatibacter actinomycetemcomitans affect host defenses?

By killing white blood cells Signup and view all the answers

Which of the following factors is part of the multifactorial aetiology of periodontal disease?

Genetic predisposition Signup and view all the answers

What is a common consequence of the proteases produced by Aggregatibacter actinomycetemcomitans?

Destroying fibroblasts Signup and view all the answers

Which of the following is NOT an aspect of the multifactorial aetiology of periodontal disease?

Fungal infections Signup and view all the answers

Study Notes

Oral Bacteria in Periodontal Disease

Oral bacteria are categorized by their location within the mouth (supragingival vs. subgingival) and oxygen requirements (aerobic, anaerobic, facultative).
Supragingival bacteria, typically gram-positive, include streptococci and actinomyces.
Subgingival bacteria, typically gram-negative, include Porphyromonas gingivalis, Prevotella intermedia, and fusobacteria.

Dental Plaque and Biofilm

Dental plaque is a biofilm, a complex community of microbes.
Some subgingival microbes are free-floating or loosely attached instead of tightly in the pocket.
An extracellular slime layer protects these microbes and creates fluid channels within the plaque.

Periodontal Pathogens and Virulence Factors

Porphyromonas gingivalis (Pg) is a gram-negative bacterium involved in periodontal disease.
Tannerella forsythia (Tf), Treponema denticola (Td), and Aggregatibacter actinomycetemcomitans (Aa) are other key periodontal pathogens.
Virulence factors of these bacteria include the production of proteinases, like gingipains, which degrade host tissue.
Gram-negative bacteria produce endotoxins (lipopolysaccharide).
Haemagglutination, allowing the bacteria to acquire nutrients, adhesion to host cells, and tissue invasion, are also common virulence methods.

Microbial Transition from Health to Disease

Tannerella forsythia: This bacterium is more prevalent in periodontitis than in gingival health. It produces proteases and factors that induce apoptosis (cell death).
Treponema denticola: This motile bacterium uses gingival crevicular fluid (GCF) components for energy and multiplication, adheres to fibroblasts, and disrupts host defenses by affecting cytokine regulation.. It also delays wound healing.
Porphyromonas gingivalis: Pg produces gingipains, uses GCF for nutrients, has a capsule to resist host defenses, and produces lipopolysaccharide (LPS). It also possesses haemagglutinin and platelet aggregation factors.
Aggregatibacter actinomycetemcomitans: This bacterium is associated with aggressive periodontitis. It produces leukotoxin (kills white blood cells), and toxins that damage fibroblasts and epithelial cells.

Aetiology of Periodontal Disease

Periodontal disease is multifactorial, with microbial factors playing a crucial role.
Environmental factors, like smoking, poor oral hygiene, pre-existing pockets, and plaque retentive factors, also contribute to the disease.
Host defense factors, such as polymorphonuclear leukocyte (PMN) defects and certain genetic factors, influence susceptibility.

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Description

Explore the roles of oral bacteria in periodontal disease through this quiz. Understand the differences between supragingival and subgingival bacteria, as well as the significance of dental plaque as a biofilm. Delve into key periodontal pathogens and their virulence factors.