Microbiologic Specificity of Periodontal Diseases
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What is the primary focus of the Nonspecific Plaque Hypothesis regarding periodontal disease?

  • The quality of bacteria present in the plaque.
  • The role of saliva in neutralizing plaque effects.
  • The quantity of plaque and its relationship with host defenses. (correct)
  • The virulence of specific pathogens in causing disease.

    • Which observation contradicted the Nonspecific Plaque Hypothesis?

  • Mechanical removal of plaque is ineffective in preventing disease.
  • Only specific bacteria are pathogenic in periodontal disease.
  • Some individuals with little plaque developed periodontitis.
  • Individuals with significant plaque sometimes do not develop periodontitis. (correct)

    • What conclusion did the Nonspecific Plaque Hypothesis support regarding disease prevention?

  • Improved dental hygiene practices should be emphasized.
  • Complete eradication of all bacteria is required.
  • Non-specific mechanical removal of plaque is key. (correct)
  • Nutritional changes are necessary for prevention.

    • What did the acceptance of the Specific Plaque Hypothesis primarily depend on?

    <p>Identification of specific pathogenic microorganisms.</p> Signup and view all the answers

    What aspect of the Nonspecific Plaque Hypothesis was challenged by improved bacterial isolation techniques?

    <p>The assumption that any plaque is equally harmful.</p> Signup and view all the answers

    What does the Specific Plaque Hypothesis predict regarding plaque composition?

    <p>Only a few specific microorganisms in plaque can be pathogenic.</p> Signup and view all the answers

    How does the current clinical treatment for periodontal disease often relate to the Nonspecific Plaque Hypothesis?

    <p>It continues to support mechanical removal of plaque.</p> Signup and view all the answers

    What is a key factor that challenges the idea of nonspecific pathogenicity in dental plaque?

    <p>The variance in disease expression in affected sites.</p> Signup and view all the answers

    What is one significant limitation of antibiotics used in periodontal therapy?

    <p>Long-term use can lead to bacterial resistance.</p> Signup and view all the answers

    Which of the following is NOT considered a potential periopathogen in periodontal disease?

    <p>Corynebacterium</p> Signup and view all the answers

    According to the updated Non-specific Plaque Hypothesis, how does microbial colonization contribute to gingivitis?

    <p>Microbial colonization in sufficient quantity can cause at least gingivitis.</p> Signup and view all the answers

    What was concluded about the use of chlorhexidine in managing periodontal disease?

    <p>Its extensive use may be questioned due to uncertain effects.</p> Signup and view all the answers

    What is a major consideration of the updated Non-specific Plaque Hypothesis?

    <p>The overall activity of multiple microbes may initiate disease.</p> Signup and view all the answers

    What observation supports the assertion that some people can have lifelong gingivitis without progressing to periodontitis?

    <p>Some individuals lack specific factors that lead to tissue destruction.</p> Signup and view all the answers

    How are the species involved in periodontal disease described according to the findings?

    <p>Approximately 50% of species are uncultivable and poorly understood.</p> Signup and view all the answers

    What does the statement about 'any microbial colonization of sufficient quantity' imply about periodontal health?

    <p>A threshold level of microbial presence can lead to tissue inflammation.</p> Signup and view all the answers

    What is the primary role of keystone pathogens in polymicrobial diseases?

    <p>They may trigger inflammation when present in low numbers.</p> Signup and view all the answers

    How does Porphyromonas gingivalis manipulate the immune system?

    <p>By influencing the response of toll-like receptors.</p> Signup and view all the answers

    Which mechanism is NOT involved in the impairment of host defenses by P. gingivalis?

    <p>Direct stimulation of neutrophil production.</p> Signup and view all the answers

    What is the significance of E-selectin in the context of periodontal health?

    <p>It facilitates adhesion and migration of neutrophils.</p> Signup and view all the answers

    In which context is the 'KPH' most relevant?

    <p>Developing diagnostic tools for polymicrobial diseases.</p> Signup and view all the answers

    What type of lipopolysaccharides does P. gingivalis use in manipulating the TLR response?

    <p>Type I and Type II.</p> Signup and view all the answers

    Why is interleukin 8 (IL-8) important in periodontal tissue?

    <p>It serves as a key neutrophil chemo-attractant.</p> Signup and view all the answers

    What characterizes a keystone pathogen compared to dominant species?

    <p>Keystone pathogens can influence host immune response at low numbers.</p> Signup and view all the answers

    What is the role of Type I LPS in relation to TLR4?

    <p>Activates the immune system</p> Signup and view all the answers

    How does P. gingivalis affect IL-8 production in the oral cavity?

    <p>Blocks IL-8 production</p> Signup and view all the answers

    What is the effect of hemin concentration in the oral cavity?

    <p>Increases Type II LPS expression</p> Signup and view all the answers

    What role do gingipains play in the complement system response?

    <p>Cleaves complement factors and degrades their function</p> Signup and view all the answers

    What is a proposed consequence of local chemokine paralysis by P. gingivalis?

    <p>Delayed neutrophil recruitment</p> Signup and view all the answers

    What is the relationship between C5a receptor (C5aR) and TLR2 in the context of P. gingivalis?

    <p>C5aR crosstalk with TLR2 leads to increased inflammation and impaired leukocyte function</p> Signup and view all the answers

    Which of the following statements about P.gingivalis’ interactions with the immune system is accurate?

    <p>Its gingipains can disarm complement factors</p> Signup and view all the answers

    What distinguishes Type II LPS in terms of immune response?

    <p>It inhibits the immune response to P.gingivalis</p> Signup and view all the answers

    What does the Ecological Plaque Hypothesis (EPH) suggest as a cause for dental disease?

    <p>An imbalance in the total microflora due to ecological stress.</p> Signup and view all the answers

    According to the Updated NSPH, what factor significantly contributes to differences in pathogenic potential of dental plaque?

    <p>Differences in plaque microbial composition.</p> Signup and view all the answers

    Which of the following statements aligns with the Traditional Ecological Plaque Hypothesis (EPH)?

    <p>It recognizes the influence of both bacterial metabolism and host environment.</p> Signup and view all the answers

    What is a key characteristic of keystone species as described in the Keystone Pathogen Hypothesis (KPH)?

    <p>They have a limited overall abundance but a significant impact on the environment.</p> Signup and view all the answers

    Which ecological factors are influenced by changes in microbial composition in dental plaque?

    <p>pH, nutrients, and redox potential.</p> Signup and view all the answers

    Which factor is NOT addressed by the traditional Ecological Plaque Hypothesis?

    <p>The genetic factors of the host influencing plaque composition.</p> Signup and view all the answers

    What role do early colonizers of supragingival dental surfaces typically play?

    <p>They occupy space and prevent disease-causing bacteria from settling.</p> Signup and view all the answers

    Why is the identification of keystone pathogens considered clinically important?

    <p>It can lead to targeted treatments for inflammatory diseases.</p> Signup and view all the answers

    Study Notes

    Microbiologic Specificity of Periodontal Diseases

    • The traditional nonspecific plaque hypothesis (NSPH) proposed that the amount of plaque determined its pathogenicity.
    • This hypothesis suggested that the host has a threshold for neutralizing toxic products from plaque. Exceeding this threshold leads to disease.
    • However, observations contradicted this. Some individuals with significant plaque and calculus did not develop destructive periodontitis (gum disease).
    • There was also site-specificity to the disease, with some sites unaffected in individuals despite advanced disease in others.

    Specific Plaque Hypothesis

    • The specific plaque hypothesis (SPH) proposes that only specific pathogenic microorganisms, in plaque, cause periodontal disease.
    • The acceptance of the SPH was aided by the discovery of A. actinomycetemcomitans as a pathogen in aggressive periodontitis.
    • However, several limitations to the usefulness of the SPH were identified, including antibiotic resistance in clinical settings and uncertainty regarding the effect of chlorhexidine.

    Ecologic Plaque Hypothesis

    • The ecological plaque hypothesis (EPH) suggests that periodontal disease results from an imbalance in the total microbial flora, and not just the quantity of plaque.
    • This imbalance could be caused by environmental stress, resulting in an increase in the relative abundance of "oral pathogens."

    Keystone Pathogen Hypothesis

    • The keystone pathogen hypothesis (KPH) highlights the disproportionate effects of certain low-abundance microbial pathogens.
    • This hypothesis asserts that these keystone pathogens significantly impact the oral microbiota, and can cause inflammatory disease by increasing other normally present microorganisms and causing changes in composition.

    Porphyromonas gingivalis

    • P. gingivalis's various mechanisms impair host defenses by manipulating the TLR response, altering the interleukin-8 (IL-8) response, and subverting the complement system.

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    Description

    Explore the differences between the traditional nonspecific plaque hypothesis and the specific plaque hypothesis in periodontal diseases. Understand how specific microorganisms, like A. actinomycetemcomitans, play a role in disease pathogenesis and the implications for treatment. This quiz will help clarify key concepts in periodontal microbiology.

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