bacterial etiology of caries

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bacterial etiology of caries
2011-01-21 09:34:37

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  1. Factors influencing hydroxyapapite solubility
    • pH
    • fluorid
    • ionic strength of solvent (enamel partially dissolves in pure H2O)
    • temperature
    • Ca2+ and PO4- concentration (both in saliva)
  2. Hydroxyapatite crystals are stable
    at physiological pH of ____
    though small amounts of demineralizationÛremineralization can
  3. Can caries heal?
    no bu t you can retore it
  4. How did animal studies help the study of caries?
    • 1960 hamster model shows caries infections are transmissible
    • Germ & caries free animals acquire
    • caries upon microbe exposure
    • Gnotobiotic rodent studies indicated importance
    • of species of the Streptococcus genus for producing caries
    • Animal studies confirmed sugar relationship with caries germ free rodents did not develop caries in presence of sucrose
    • - if exposed to bacteria at later time in presence of sucrose®caries
  5. What are the human studies on caries
    • Sognnaes study: sugar rationing resulted in decrease caries in children
    • Vipeholm: sucros high diets increased caries incidence. sticky and adhesive form for food increase it too
    • Australian orphanage sugar0free diet offered protection but not long
  6. How does children between 6-30 months become infected with bacteria?
    Exchange in the family unit
  7. MS can be trasnsmitted from mother to ____.
  8. CHildren's caries patterns more closely to mothers or fathers caries experience?
  9. MS can colonize the mouths of whom?
    pre-dentate infants
  10. the 2nd window for MS to affect children is when?
    6 years old
  11. biofilm is consists of what 3 things?
    liquid + bacteria + surface
  12. what is the 3 stages in biofilm life cycle?
    • 1. attachment
    • 2. growth
    • 3. dispersal
  13. Dental plaque forms naturally on teeth and, indeed,
    forms part of the host’s defenses by helping to prevent colonization by what?
    exogenous (and often pathogenic) microorganisms.
  14. How many different species are there in the flora of the oral cavity?
    200: anaerobic and facultative aerobic
  15. many bacteria can not adhere to pellicle coated teeth yet can adhere to ______ and other bacterial species
  16. _______ are the major pathogens of human dental caries.
    Mutans Streptococci (MS)
  17. What does MS produce and grow in?
    • Produces acid : acidogenic
    • grows in acid: acidouric
  18. Streptococci species are __________ and _____ shaped.
    • facultative aerobes
    • cocci shaped
  19. T or F. low-pH non- MS can also have a big part in caries.
  20. Enamel caries initially irreversible. T or F
    F it is reversible
  21. If bacteria enter lesion, _____________ of bacteria is required.
    mechanical removal
  22. what are the host factors in saliva that prevent caries?
    • 1. lysozyme: hydrolyzes peptidoglycan of bacterial cell wall
    • 2. Lactoferrin: binds iron essential for bacterial growth. Iron required for function of many bacterial proteins. This protein has otehr anti-microbial properties.
    • 3. Lactoperoxidase: produces hypothiocyanate ion. Ion reacts with bacterial enzyme sulfhydral groups, inhibiting enzyme
    • 4. Immunoglobins: IgA, IgG, IgM
  23. How does saliva help prevent caries?
    • -helps clear mouth of food, cellular and bacterial
    • debris; this helps reduce nutrients for plaque growth
    • -buffers pH
    • -lots of calcium, phosphate-this promotes enamel remineralization
  24. Why can't caries vaccine be feasible?
    • 1. complex flora associated with caries
    • 2. ability of bacteria to rapidly mutate
    • 3. S. mutans contains antigens similar to heart muscle
  25. What are the most cariogenic species for enamel caries? (2)
    • S. mutans
    • Lactobacillus