oral microbiota (19)

• What is the definition of an ecosystem?

  Community interaction of organisms and environment
• What processes emerge from the interactions in an ecosystem?

  Energy exchange and cycling of elements
• What is the term for a large ecosystem composed of primary ecosystems?

  Ecosystem
• What are the components of the oral cavity ecosystem?

  1. Buccal mucosa
  2. Tooth surface
  3. Acquired salivary pellicle
  4. Dental plaque
  5. Prosthodontic and orthodontic appliances
  6. Gingival sulcus
  7. Saliva
• What regulates ecosystems according to the study material?

  Internal and external factors
• What do qualitative and quantitative characteristics of microbiota determine?

  Health or illness in ecological niches
• What is the nature of the oral cavity ecosystem?

  Open and dynamic
• What causes variability in the oral cavity ecosystem?

  Qualitative and quantitative differences among individuals
• What factors contribute to the heterogeneity of the oral cavity ecosystem?

  Different bacterial species and habitats
• How many bacterial species can live in the mouth?

  More than 700 species
• What is the bacterial concentration in saliva?

  $10^8 \text{ bacteria/ml}$
• What is the bacterial concentration in dental plaque?

  $10^{11}-10^{12} \text{ bacteria/g}$
• What is the specificity of Streptococcus mutans?

  Present on hard surfaces
• What are the characteristics of the oral mucosa?

  • Comprises lips, tongue, cheeks, and palate
  • Lips, cheeks, and palate: sparsely colonized
  • Tongue: highly colonized with papillae
  • Reservoir of obligate anaerobes
• What are the characteristics of tooth surfaces in the oral ecosystem?

  • Non-shedding surface for bacterial colonization
  • Different surfaces for bacterial colonization
  • Each surface presents different microflora
• What is the acquired salivary pellicle?

  • Acellular layer formed by salivary components
  • Protective against tooth decalcification
  • Allows bacterial colonization
• What is dental plaque?

  • Biofilm of microorganisms adhering to tooth surface
  • Composition varies with time and location
  • Embedded in mixed abiotic material
• What are prosthodontic and orthodontic appliances?

  • Artificial materials for dental restoration
  • Used in orthodontic therapy
  • Include various dental elements
• What is the gingival sulcus?

  • Space between marginal gingiva and tooth surface
  • Starts at free margin of gingiva
  • Ends at junctional epithelium
• What is the main function of saliva?

  • Keeps the mouth moist
  • Softens and lubricates food
  • Aids in swallowing
• What factors modify the habitat of the mouth?

  • Age
  • Anatomical location
  • Physico-chemical factors
  • Nutritional factors
  • Host protective factors
• How does age affect the oral environment?

  Varies from birth to elderly stages
• How does anatomical location affect oral microorganisms?

  Different surfaces shed differently
• What is the normal pH range in the oral cavity?

  Between 6.7 and 7.5
• What happens to pH after consuming sugar-rich foods?

  pH decreases
• What is the typical temperature in the oral cavity?

  About 37°C
• What factors affect oxygen levels in the oral cavity?

  Anatomical and microbial factors
• What strategies do microorganisms use to avoid elimination?

  • Adhesion to tissues
  • Aggregation of same species
  • Co-aggregation of different species
• What are adhesins in bacteria?

  Elements that attach organisms to tissues
• What is the role of fibronectin in adhesion?

  Acts as a receptor in epithelial surfaces
• What are the mechanisms of adhesion, aggregation, and co-aggregation?

  1. Lectin-carbohydrate binding
  2. Protein-protein binding
  3. Glucans mediated binding
  4. Lipoteichoic acid binding
  5. Retention in specific areas
• What is glucans mediated binding?

  Involves adherence to hard surfaces
• What does S. mutans use for adherence?

  GTF, glucans, and surface proteins
• What is the role of lipoteichoic acid in bacteria?

  Allows adherence to hard surfaces
• How do bacteria obtain nutrients?

  From endogenous, interbacterial, and exogenous sources
• What is the nutrient content of saliva?

  Low nutrient content
• What are endogenous sources for bacteria?

  From host tissues and secretions
• What are interbacterial sources for bacteria?

  Sources obtained from other bacteria
• What are exogenous sources for bacteria?

  Sources obtained from external food
• What are the three factors involved in binding for S. mutans?

  Nonsoluble glucans, surface proteins, GTF