patients that cannot metabolize fructose found to have 90% reduction in caries. Populations w/o sucrose in diet leads to what?
much lower incidences of caries
why is sucrose the most cariogenic of dietary sugars?
It releases more than 2x the energy of others.
Explain the 3 stages of the biofilm life cycle.
1. attachment: free-floating (planktonic) find a place and w/in minutes become attached. They begin to produce slimy extracellular polymeric substances (EPS) and to colonize the surface.
2) EPS production allows the emerging biofilm
community to develop a complex, three-dimensional structure that is influenced
by a variety of environmental factors. Biofilm communities can develop within hours.
3) Biofilms can propagate through detachment of
small or large clumps of cells, or by a type of "seeding dispersal" that releases individual cells. Either type of detachment allows bacteria to
attach to a surface or to a biofilm downstream of the original community.
some bacteria utilize ______ produced by S. mutans and lactobacillus as a nutrient source.
lactic acid
some bacteria can produce vitamin ___, a growth requirement for other bacteria
vitamin K
aerobic bacteria can consume oxygen and produce ROS that are especially toxic to _________.
obligate anaerobes
in the first 0-4 hours, which microbial flora exist on the enamel pellicle?
predominantly streptococci such as S. sanguis and S. oralis (only 2% of initial streptococci are mutans)
some gram negatives Actinomyces
after initial adherence, plaque grows due to what?
bacterial growth and cell division
adherence of other bacteria
Glucans produced by initial adherent bacteria improve binding of S. mutans at later time in growth of plaque.
T
plaque becomes more acidic/basic as it thickens?
acidic
what is the most frequently isolated species from oral cavity?
S. sanguis
MS are neither a unique casuative agent for white spot lesions, nor a mian determinant of the acidogenicity of plaque. T or F
T
the pH-lowering capacity of plaque may be related to the proportion of the what?
low pH non MS
which species is important in root surface caries?
Actionomyces
characteristic of Actionomyces are....
gram +
aerotolerant anerobe
what 2 species are important in dentinal caries?
Lactobacillus and Actionomyces
what is the action of lysozyme-saliva enzyme?
it hydrolyzes peptidoglycan
enzyme is in saliva, tears, mucus
it cleaves beta 1,4 glycosidic linkages of peptidoglycan
a glycosidase, not a protease
what does IgA do?
agglutinates bacteria
prevents adherence
has secretory associated protein which facilitates transport of IgA into saliva and appears to prolong stability
gingival sulcular fluid also secretes immunological components. Possible mechanism for host protection
