Microbiology of Caries (Amaechi 2) Flashcards by Dakota Miller

Discovery of microbes: _________ (1632-1723) developed the microscope and was the first to discover oral bacterial flora: “I didn’t clean my teeth for three days and then took the material that had lodged in small amounts on the gums above my front teeth…. I found a few living animalcules..”

Anton Van Leeuwenhoek

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Oral cavity of man is _____ at birth.

sterile

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The oral microorganisms are acquired shortly after birth. A significant alteration in these microorganisms occurs _____ (predentate) and _____ (dentate) tooth eruption.

before and after

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Gram positive bacteria of human oral flora

-Streptococcal spp.: S. salivarius S. sanguis S. mutans* S. milleri -Non-Streptococcal spp.: Actinomyces spp.* Corynebacterium spp. Lactobacillus spp.* Staphylococcus spp.

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Gram-negative bacteria of human oral flora

Bacteroides spp. Fusobacterium spp. Neisseria spp. Veillonella spp. Haemophilus spp.

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The major organisms associated with dental caries in man are…

-Streptococci (particularly S. mutans) -Lactobacilli -Actinomyces -Bifidobacteria (more recently)

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S. mutans was first recognized as cariogenic bacteria by ______ in 1924 when he isolated it from a caries lesion.

JK Clarke

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_____ (1970) went further to define 5 serotypes a, b, c, d, e, (f, g and h subsequently added) based on serological specificity of carbohydrate antigens.

Bratthall

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Strep. species associated with caries are…

-S. mutans: c, e, f -S. sobrinus: d, g, h

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S. mutans serotype ___ causes caries on all types of surfaces

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Virulence factors of SM as caries-inducing organisms includes expression of surface antigen ______.

Adhesin

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Virulence factors of SM as caries-inducing organisms includes expression of ________ and ________.

-Glucosyltransferase (gtf B,C, D) -Fructosyltransferase (ftf)

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Virulence factors of SM as caries-inducing organisms includes expression of _________.

Glucan binding proteins (GBP)

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Virulence factors of SM as caries-inducing organisms includes acidogenicity, such as efficient and faster _______ and production of _______.

-Sucrose metabolism -Stronger acid

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Virulence factors of SM as caries-inducing organisms includes dual metabolic systems for adaptation to _________.

High and low sugar concentrations

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Bacterial metabolic systems: Proton-motive force (PMF) system - ____ affinity sugar uptake system activated by a proton motive force (pmf) and operates at _____ pH.

-Low -Low pH

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Bacterial metabolic systems: PMF is possessed by Streptococci, especially ______; it allows the cell to continue to transport and metabolize sugars under acidic conditions which are unfavorable to other bacteria.

S. mutans

Bacterial metabolic systems: Phosphotransferase (PTS) system - a ____ affinity sugar uptake mechanism driven by phosphoenol pyruvate (PEP) and operates at _____ pH.

-High -Neutral

Streptococci do not possess the enzymes of the Kreb’s cycle or cytochromes, so they produce energy via _________.

Anaerobic glycolysis

Streptococci do not possess the enzymes of the Kreb’s cycle or cytochromes, so they produce energy via _________.

Anaerobic glycolysis

-Strep. mutans -Lactobacilli -Ferment sugars producing 90% or more lactic acid as their end products

Homofermentative bacteria

-Produce mixture of metabolites including organic acids -E.g. acetic, formic, propionic, butyric, succinic acids

Heterofermentative bacteria

Virulence factors of SM as caries-inducing organisms includes the ability to survive and multiply at acidic pH, also known as ______.

Aciduricity

Lactobacilli

-Acidogenic (Homofermentative: L. casei, L. acidophilus; Heterofermentative: L. fermentum) -Aciduric

Lactobacilli can be found in the saliva and dental plaque, usually present in high numbers when something is wrong, such as…

caries, dry mouth, poor oral hygiene, frequent sugar consumption

Lactobacilli is associated with ________ caries lesions & its progression and are associated with _______ caries.

-Established -Deep dentinal

Do not adhere to tooth surfaces; they need ________ (Pits/fissures, Cavities, Orthodontic devices).

Retention niches

Lactobacilli is found in the _____ when open cavities present and only makes up a _____ fraction of plaque flora (1 in 10^4).

-Saliva -Minor

Significant correlation b/w _______ and the lactobacilli count in both children and adults

caries lesions

Recent study reported that the presence of \_\_\_\_\_\_\_\_\_, not S. mutans, was associated with caries occurrence.

Visible plaque

Actinomyces

-Gram + rods/filaments -Facultative anaerobes: A. naeslundii, A. viscosus -Strict anaerobes: A. israelli, A. odontolyticus

Characteristics of Actinomyces as caries inducing organisms include \_\_\_\_\_\_\_\_, mostly lactic acids also acetic, succinic, formic.

Glucose fermenters

Actinomyces spp predominate in _______ plaque

sub-gingival

\_\_\_\_\_\_\_ and ________ has also related with root caries.

A. viscosus and A. naeslundii

\_\_\_\_\_\_\_\_ may constitute 50% of organisms in plaque of children

Actinomyces

\_\_\_\_\_\_\_\_\_ has been linked with early stages of demineralization

A. odontolyticus

\_\_\_\_\_\_ are rather new as caries-associated microorganisms. Detected in higher proportions and frequency than ______ and Produce extracellular polysaccharides, so could form biofilm (\_\_\_\_\_\_\_\_\_).

-Bifidobacteria -S. mutans -Dental plaque

\_\_\_\_\_\_ and ______ are significantly associated with caries. They are found in high numbers in caries lesions of children and adults. Salivary bifidobacteria is \_\_\_\_\_-associated in older adults .

-B. dentium and Scardovia wiggsiae -Caries

\_\_\_\_\_\_\_\_ levels were positively associated with the number of filled and decayed tooth surfaces (DFS). Bifidobacteria were isolated from saliva, supragingival plaque, and infected dentin.

Salivary Bifidobacteria

Found in _______ lesions in adults and ________ in adults and children.

-root caries -occlusal lesions

These information suggest that bifidobacteria may play a role in the progression of __________ in both children and adults.

Occlusal caries lesions

Mecahnism of glucosyl transferase, frutosyl transferase, and invertase.