Flashcards in Oral Micro Final Deck (100):
Caries is a disease caused by microorganisms feeding on what?
Remineralization can occur in the early stages of Caries.
What are the 4 factors contributing to caries?
Teeth and their environment
*quality/quantity with each
What is the Main and 2 Minor ingredients to the Organic Matrix of teeth?
Protein (like collagen)
mucopolysaccharides, chondroitin sulfate
Name 5 positive ions and 2 negative Secondary ions that can make up teeth.
Lead, zinc, strontium, silver, nickel, iron
Enamel is ___% mineral and dentine is ____% mineral.
Describe hydroxyapatite crystal.
Phosphate and Calcium star of david
In Hydroxyapatite, what can substitute OH?
What substitutes Phosphate?
What 5 substitutes for Calcium?
Fluoride for OH
Carbonate for Phosphate
Lead, strontium, radium, Iron, Magnesium for Calcium
What is the critical pH for net loss and demineralization of the tooth?
*above net gain, below net loss
What is more resistant to acid than optimally fluoridated human teeth?
Beaver enamel - lots of Iron instead of Calcium
Hydroxyapatite is covalently linked
With enamel maturation, the regularity of the hydroxyapatite crystals tend to increase ______
Why can free ions diffuse into the mineral lattice of enamel?
Hydroxyapatite is essentially insoluble at neutral pH
What 2 ions are essentially in a saturated state (ready to precipitate) in the body?
*rxn goes to right, dissolution, left, remineralization
Limited access for saliva, plaque retention, pits/fissures are all caries-suceptible.
The occlusal surfaces of Molars and Premolars most are susceptible to caries where?
Pits and fissures
______ of molars and _______ of maxillary incisors are susceptible to caries.
What approximal surface site is susceptible to caries?
Cervical to contact
The cervical margin just coronal to the gingival margin is susceptible to caries
In patients with gingival recession ________ surfaces area susceptible to caries.
Exposed root surfaces
Margins of deficient restorations, and tooth surfaces adjacent to dentures and bridges are susceptible to caries
Limited saliva access favors what?
What is the sequence of plaque development?
Salivary proteins > Pellicle > Plaque bioflim > calculus
What is the acellular, homogenous, organic film that forms on enamel by selectively adsorbing glycoproteins and salivary proteins?
Are bacteria necessary for the formation of Pellicle?
If the Pellicle is removed by meticulous cleaning, it takes how long to re-form?
Minutes to hours
The pellicle serves to protect the tooth
*maybe, but not proven
The plaque biofilm is soft and non-mineralized
What are the 3 layers making up the Plaque Biofilm?
Pellicle (plaque-tooth interface)
Insoluble Intercellular matrix
What 2 things make up the Insoluble intercellular matrix of the plaque biofilm?
Carbohydrates (glucans, fructans, other polysaccharides)
*CHO produced by the bacteria
The metabolic fermenting process of bacteria on teeth of CHO produces what? (2 things)
*some plaque bacteria produce these 2
Once inorganic deposits are present in plaque biofilm, what has formed?
What does this greatly increase risk for?
Germ free animals do not develop caries even when fed a cariogenic diet
What is the term for known oral flora used in testing?
What are the experiments called?
Testing using gnotobiotic animals in add-back experiments have implicated what 3 species of bacteria in caries?
Caries is an infectious disease
Would bubble boy have dental caries?
I think so.
Still has a microbiome, just prone to infectious disease.
Name 3 byproducts of bacterial CHO metabolism
What is a homolactic acid producer?
Produces only lactic acid
other acid (or ethanol), lactic acid
What are the 2 major Streptococci implicated in caries?
Mutans streptococcus attaches to Oral Biofilm, is a good CHO transporter at low pH, and is a _______ fermenter.
*so all Lactic Acid
What is Mutans preferred pH?
Acidophilic - likes low pH
What insoluble product does Mutans produce?
Glucan (aka Mutan aka Dextran)
**decreases buffer availability, increases acid conc.
What are the 2 types of "snacks" Mutans makes itself?
Extracellular Levan (frc polymer)
Most oral bacteria have excellent sugar transport at low pH
Tolerating a high acidity environment is ______
Preferring acidic environment is ______
What do Mutans do with extra glucose?
Make insoluble glucans
What is the small molecule that S. mutans uses to kill their competitors?
What acts as a selective killer for mutans?
What is the Xylitol mechanism in Mutans?
Ingests, phosphorylates, then kicks out
*all uses ATP
What are the 3 sucrose enzymes on the surface of S. mutans?
Glucosyl Transferase (makes Insoluble matrix)
Invertase (splits into frc/glc and send inside cell)
Fructosyl Transferase (makes Levanase)
Why wouldn't HFCS end up as a structural component?
What is the metabolic consequence?
Glucosyl Transferase and Fructosyl Transferase both need Sucrose
Makes more Lactic Acid
What is more cariogenic, sucrose or HFCS?
Sucrose, because the Extracellular Dome is more important in caries formation than Acid.
Levan is made from chains of...
Levan is broken down by what?
The insoluble ECM made by mutans is made from chains of...
What 2 bacterial species have Fructosyl Transferase and can therefore make Levan?
What S. mutans enzyme has the highest affinity for Sucrose?
*snacks, ECM only produced in abundance.
What does Fluoride inhibit in bacterial metabolism?
(which creates phosphoenol pyruvate > PEP > Pyruvate > lactate)
What are the 3 major ways F- lowers the risk of caries?
Most electronegative element, so holds hydroxyapatite more tightly
Decreases Carbonate (by binding tightly)
Poisons key metabolic enzymes (enolase) to Lower Acid Production
Anti-caries mechanisms fall into what 2 very general mechanisms?
Which is more important?
Topical (after eruption)
Topical most important
A diet high in sugar selects for what?
Aciduric bacteria (able to tolerate lots of acid)
What 2 species are found in very low numbers in "healthy" plaque?
(mutans and L. casei increase after sugar increase)
Aciduric bacteria increase most when _____ is excluded
What is the term for pH affecting the type of bacteria that can grow?
What 3 bacteria are in much higher percentage at caries sites?
Why does Mutans compete so well at low pH?
Even though produces less acid, produces more than most even at low pH
What are the 4 major locations of caries formation?
What is the major cause of caries in Pits/Fissures?
What is the major cause of caries on Smooth Surfaces?
What is the major cause of caries in Dentin?
What other pathology mirrors this?
S. mutans, Actinomyces spp., Lactobacillus spp.
*mutans does the drilling
What infections are generally a mixture of various G- anaerobes?
What are cause Primarily by G- anaerobes (and facultative)?
Endodontic pulp infections
Are caries vaccines theoretically possible?
Caries can arise even without sugar
What are the 2 most acidic byproducts of bacterial metabolism of Pyruvate in the mouth?
Formic acid - 3.7
Lactic acid - 3.8
**for some reason, Lactic acid is considered to by the most "powerful" of these acids
Name 7 byproducts of bacterial metabolism in the mouth.
What graphical representation demonstrates the rapid and sustained drop in pH upon ingestion of CHO?
Plaque can have a lower "resting" pH, and that plaque leads to rampant caries
Brushing teeth lowers the amount of acid produced
What 2 factors determine how well a CHO can be cariogenic?
Plaque bacteria use what kind of CHO most effectively?
What is more important than the amount of CHO consumed?
What regulates salivary secretion?
parasympathetic - good flow, watery
sympathetic - low flow, thick
What is the salivary flow rate?
(between meals - small. Sleep - small)
What 2 ingredients does Saliva contain that helps tooth remineralization?
Why can they precipitate on teeth?
Ca and PO4
What are 2 antimicrobials contained in Saliva?
Lysozym and Antibody
Saliva acts as a buffer and maintains mouth pH near 7 through bicarb and recycles topical fluoride
Caries incidence has increased recently
When should fluoride gel be given?
There has been some headway in using engineered antibody to bind attachment fibers of cariogenic bacteria
*this would be a vaccine
Why does a broad spectrum prevention seem to be counterproductive?
Often bad strains survive
What is STAMP?
Specifically targeted anti-microbial peptides
**reduced S. mutans by 50%
GMO germs and probiotics are possible prevention avenues
The probiotic theory of prevention relies on what mechanism?
What is the main Ab that activates the complement cascade?
Probiotics lower Neonatal Necrotizing Enterocolitis by how much?
There have been modest to good results in probiotic treatment for gingivitis, halitosis, dental caries, and periodontal disease.
*periodontal hardest to carry out, in vivo animal exp's promising
What is a common probiotic species influential of a healthy mouth (or lack of caries)?