Caries Flashcards
Bacteria in biofilms on the surface of the tooth produce ___________ from glycolysis of sugars.
Lactic acid
Lactic acid drops ___ and the mineral matrix of the tooth dissolves.
pH
Why is the initial demineralization only on the subsurface, leaving a thin layer of enamel overlying the lesion?
Pellicle proteins stabilize the surface
Once ___________ occurs, biological repair is no longer possible.
Cavitation
Why is remineralized tooth structure stronger than virgin enamel?
Incorporation of fluoride
What is the most important property of caries-causing bacteria?
They continue to produce acid at low pH
What species cause initial caries?
- Strep mutans
- Other strep (sobrinus, salivarius)
- Veillonella
- Actinomyces
What species cause caries progression?
- S. Mutans
- Lactobacillus casei, rhamnosus, gasseri, fermentum
- Bifidobacterium and scardovia
What is the most common supragingival organism?
Streptococci
What is the only nutrient source for S. Mutans?
Carbohydrates
T/F: S. Mutans is good at surviving during feast and famine.
True
What strep is very closely related to strep mutans?
S. Sobrinus
T/F: S. Mitis is a caries causing bacteria.
False
What is the earliest acquired oral bacteria?
S. Mitis
What strep is found in healthy plaque and is a good initial colonizer of the pellicle?
S. Sanguinis
T/F: S. sanguinis produces cannot produce lactic acid at low pH.
True
What bacteria may be associated with root caries?
Actinomyces
T/F: Actinomyces is anaerobic.
True
T/F: Veillonella ferments carbohydrates to create lactic acid.
FALSE
Protects against acid by fermenting lactate
At what point do lactobacilli play a role?
Established or deep lesions
What is the initial process of attachment for caries development?
S. Sanguinis binds to pellicle -> s. Mutans binds to s. Sanguinis -> s. mutans makes extracellular matrix
How does S. Mutans make extracellular matrix?
Uses glucosyltransferase (Gtf) to make ECM from sucrose
What is the major component of the ECM?
Glucan
T/F: S. Sanguinis does better than s. Mutans at low pH.
False
S. Mutans dominates at low pH
What is the major difference between good and bad bacteria?
Good = grow and make acid at high pH but stop at low pH
Bad = Grow and make acid best at low pH
What is the short term effect of sugar consumption?
Drops the oral pH
What is the long term effect of sugar consumption?
Selection for cariogenic bacteria over healthy bacteria
What would be the targets of a caries vaccine?
Gtf and glucan binding proteins
What are the two types of vaccines under investigation for caries?
Active immunity = mucosal vaccination; need adjuvants
Passive immunity = antibodies grown in tobacco plants and cows milk
What is replacement therapy?
Replace wild-type S. Mutans with strain that does not produce lactate
What is a STAMP?
Antibody guided antimicrobial
