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Flashcards in Oral Micro Final Deck (100)
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1
Q

Caries is a disease caused by microorganisms feeding on what?

A

Fermentable carbohydrates

2
Q

T/F

Remineralization can occur in the early stages of Caries.

A

True

3
Q

What are the 4 factors contributing to caries?

A

Microorganisms

Metabolic Substrates

Teeth and their environment

Time

*quality/quantity with each

4
Q

What is the Main and 2 Minor ingredients to the Organic Matrix of teeth?

A

Protein (like collagen)

mucopolysaccharides, chondroitin sulfate

5
Q

Ca10(PO4)6(OH)2

A

Hydroxyapatite

6
Q

Name 5 positive ions and 2 negative Secondary ions that can make up teeth.

A

Lead, zinc, strontium, silver, nickel, iron

carbonate, fluoride

7
Q

Enamel is ___% mineral and dentine is ____% mineral.

A

95%

70%

8
Q

Describe hydroxyapatite crystal.

A

OH center

Phosphate and Calcium star of david

6 Calcium

9
Q

In Hydroxyapatite, what can substitute OH?

What substitutes Phosphate?

What 5 substitutes for Calcium?

A

Fluoride for OH

Carbonate for Phosphate

Lead, strontium, radium, Iron, Magnesium for Calcium

10
Q

What is the critical pH for net loss and demineralization of the tooth?

A
  1. 5

* above net gain, below net loss

11
Q

What is more resistant to acid than optimally fluoridated human teeth?

A

Beaver enamel - lots of Iron instead of Calcium

12
Q

T/F

Hydroxyapatite is covalently linked

A

False

13
Q

With enamel maturation, the regularity of the hydroxyapatite crystals tend to increase ______

A

Spontaneously

14
Q

Why can free ions diffuse into the mineral lattice of enamel?

A

Porous

15
Q

T/F

Hydroxyapatite is essentially insoluble at neutral pH

A

True

16
Q

What 2 ions are essentially in a saturated state (ready to precipitate) in the body?

A

Calcium

Phosphate

  • rxn goes to right, dissolution, left, remineralization
  • *pH dependent
17
Q

Limited access for saliva, plaque retention, pits/fissures are all caries-suceptible.

A

True

18
Q

The occlusal surfaces of Molars and Premolars most are susceptible to caries where?

A

Pits and fissures

19
Q

______ of molars and _______ of maxillary incisors are susceptible to caries.

A

Buccal Pits

Palatal Pits

20
Q

What approximal surface site is susceptible to caries?

A

Cervical to contact

21
Q

T/F

The cervical margin just coronal to the gingival margin is susceptible to caries

A

True

22
Q

In patients with gingival recession ________ surfaces area susceptible to caries.

A

Exposed root surfaces

23
Q

T/F

Margins of deficient restorations, and tooth surfaces adjacent to dentures and bridges are susceptible to caries

A

True

24
Q

Limited saliva access favors what?

A

Plaque retention

25
Q

What is the sequence of plaque development?

A

Salivary proteins > Pellicle > Plaque bioflim > calculus

26
Q

What is the acellular, homogenous, organic film that forms on enamel by selectively adsorbing glycoproteins and salivary proteins?

A

Pellicle

27
Q

Are bacteria necessary for the formation of Pellicle?

A

no

*forms spontaneously

28
Q

If the Pellicle is removed by meticulous cleaning, it takes how long to re-form?

A

Minutes to hours

29
Q

T/F

The pellicle serves to protect the tooth

A

False

*maybe, but not proven

30
Q

T/F

The plaque biofilm is soft and non-mineralized

A

True

31
Q

What are the 3 layers making up the Plaque Biofilm?

A

Pellicle (plaque-tooth interface)

Microbial layers/colonies

Insoluble Intercellular matrix

32
Q

What 2 things make up the Insoluble intercellular matrix of the plaque biofilm?

A

Carbohydrates (glucans, fructans, other polysaccharides)

Protein

*CHO produced by the bacteria

33
Q

The metabolic fermenting process of bacteria on teeth of CHO produces what? (2 things)

A

H+

Extracellular Polymers

*some plaque bacteria produce these 2

34
Q

Once inorganic deposits are present in plaque biofilm, what has formed?

What does this greatly increase risk for?

A

Calculus

Periodontitis

35
Q

T/F

Germ free animals do not develop caries even when fed a cariogenic diet

A

True

36
Q

What is the term for known oral flora used in testing?

What are the experiments called?

A

Gnotobiotic

Add-back

37
Q

Testing using gnotobiotic animals in add-back experiments have implicated what 3 species of bacteria in caries?

A

S. mutans

Lactobacillus spp.

Actinomyces spp.

38
Q

T/F

Caries is an infectious disease

A

True

39
Q

Would bubble boy have dental caries?

A

I think so.

Still has a microbiome, just prone to infectious disease.

40
Q

Name 3 byproducts of bacterial CHO metabolism

sachrolytic bacteria

A

EtOH

Acid

Lactic Acid

41
Q

What is a homolactic acid producer?

Heterolactic?

A

Produces only lactic acid

other acid (or ethanol), lactic acid

42
Q

What are the 2 major Streptococci implicated in caries?

A

S. mutans

S. sobrinus

43
Q

Mutans streptococcus attaches to Oral Biofilm, is a good CHO transporter at low pH, and is a _______ fermenter.

A

Homolactic

  • so all Lactic Acid
  • *Acidogenic
44
Q

What is Mutans preferred pH?

A

Acidophilic - likes low pH

45
Q

What insoluble product does Mutans produce?

A

Glucan (aka Mutan aka Dextran)

  • glc polymers
  • *decreases buffer availability, increases acid conc.
46
Q

What are the 2 types of “snacks” Mutans makes itself?

A

Intracellular polysaccharide

Extracellular Levan (frc polymer)

47
Q

T/F

Most oral bacteria have excellent sugar transport at low pH

A

False

*Mutans does

48
Q

Tolerating a high acidity environment is ______

Preferring acidic environment is ______

A

Aciduric

Acidophilic

49
Q

What do Mutans do with extra glucose?

Extra fructose?

A

Make insoluble glucans

Extracellular levans

50
Q

What is the small molecule that S. mutans uses to kill their competitors?

A

Bacterioeins

51
Q

What acts as a selective killer for mutans?

A

Xylitol

52
Q

What is the Xylitol mechanism in Mutans?

A

Ingests, phosphorylates, then kicks out

*all uses ATP

53
Q

What are the 3 sucrose enzymes on the surface of S. mutans?

Functions?

A

Glucosyl Transferase (makes Insoluble matrix)

Invertase (splits into frc/glc and send inside cell)

Fructosyl Transferase (makes Levanase)

54
Q

Why wouldn’t HFCS end up as a structural component?

What is the metabolic consequence?

A

Glucosyl Transferase and Fructosyl Transferase both need Sucrose

Makes more Lactic Acid

55
Q

What is more cariogenic, sucrose or HFCS?

A

Sucrose, because the Extracellular Dome is more important in caries formation than Acid.

56
Q

Levan is made from chains of…

Levan is broken down by what?

A

Fructose

Levanase

57
Q

The insoluble ECM made by mutans is made from chains of…

A

Glucose

58
Q

What 2 bacterial species have Fructosyl Transferase and can therefore make Levan?

A

S. mutans

S. salivarius

59
Q

What S. mutans enzyme has the highest affinity for Sucrose?

A

Invertase

*snacks, ECM only produced in abundance.

60
Q

What does Fluoride inhibit in bacterial metabolism?

A

Enolase

which creates phosphoenol pyruvate > PEP > Pyruvate > lactate

61
Q

What are the 3 major ways F- lowers the risk of caries?

A

Most electronegative element, so holds hydroxyapatite more tightly

Decreases Carbonate (by binding tightly)

Poisons key metabolic enzymes (enolase) to Lower Acid Production

62
Q

Anti-caries mechanisms fall into what 2 very general mechanisms?

Which is more important?

A

Systemic (developmental)

Topical (after eruption)

Topical most important

63
Q

A diet high in sugar selects for what?

A

Aciduric bacteria (able to tolerate lots of acid)

64
Q

What 2 species are found in very low numbers in “healthy” plaque?

A

S. mutans

Lactobacillus spp.

(mutans and L. casei increase after sugar increase)

65
Q

Aciduric bacteria increase most when _____ is excluded

A

buffer

66
Q

What is the term for pH affecting the type of bacteria that can grow?

A

Bacterial succession

67
Q

What 3 bacteria are in much higher percentage at caries sites?

A

S. mutans

Actinomyces spp.

Lactobacillus spp.

68
Q

Why does Mutans compete so well at low pH?

A

Even though produces less acid, produces more than most even at low pH

69
Q

What are the 4 major locations of caries formation?

A

Pits/fissures

Smooth surfaces

Dentin

Root caries

70
Q

What is the major cause of caries in Pits/Fissures?

A

S. mutans

71
Q

What is the major cause of caries on Smooth Surfaces?

A

S. mutans

72
Q

What is the major cause of caries in Dentin?

What other pathology mirrors this?

A

S. mutans, Actinomyces spp., Lactobacillus spp.

Root caries

*mutans does the drilling

73
Q

What infections are generally a mixture of various G- anaerobes?

What are cause Primarily by G- anaerobes (and facultative)?

A

Endodontic pulp infections

Gingivitis/Periodontitis

74
Q

Are caries vaccines theoretically possible?

A

Yes

75
Q

T/F

Caries can arise even without sugar

A

False

76
Q

What are the 2 most acidic byproducts of bacterial metabolism of Pyruvate in the mouth?

A

Formic acid - 3.7

Lactic acid - 3.8

**for some reason, Lactic acid is considered to by the most “powerful” of these acids

77
Q

Name 7 byproducts of bacterial metabolism in the mouth.

A

Popionic acid

Formic acid

Lactic acid

Succinic acid

Acetic acid

EtOH

CO2

78
Q

What graphical representation demonstrates the rapid and sustained drop in pH upon ingestion of CHO?

A

Stephan Curve

79
Q

T/F

Plaque can have a lower “resting” pH, and that plaque leads to rampant caries

A

True

80
Q

T/F

Brushing teeth lowers the amount of acid produced

A

True

81
Q

What 2 factors determine how well a CHO can be cariogenic?

A

Metabolizability

Diffusion ability

82
Q

Plaque bacteria use what kind of CHO most effectively?

A

Simple sugars

83
Q

What is more important than the amount of CHO consumed?

A

Frequency

84
Q

What regulates salivary secretion?

A

Autonomic

parasympathetic - good flow, watery

sympathetic - low flow, thick

85
Q

What is the salivary flow rate?

A

1-2 mL/min

between meals - small. Sleep - small

86
Q

What 2 ingredients does Saliva contain that helps tooth remineralization?

Why can they precipitate on teeth?

A

Ca and PO4

saturated

87
Q

What are 2 antimicrobials contained in Saliva?

A

Lysozym and Antibody

88
Q

T/F

Saliva acts as a buffer and maintains mouth pH near 7 through bicarb and recycles topical fluoride

A

True

89
Q

T/F

Caries incidence has increased recently

A

True

90
Q

When should fluoride gel be given?

A

early age

91
Q

There has been some headway in using engineered antibody to bind attachment fibers of cariogenic bacteria

A

True

*this would be a vaccine

92
Q

Why does a broad spectrum prevention seem to be counterproductive?

A

Often bad strains survive

93
Q

What is STAMP?

A

Specifically targeted anti-microbial peptides

**reduced S. mutans by 50%

94
Q

GMO germs and probiotics are possible prevention avenues

A

True

95
Q

The probiotic theory of prevention relies on what mechanism?

A

Competitive exclusion

96
Q

What is the main Ab that activates the complement cascade?

A

IgG

97
Q

Probiotics lower Neonatal Necrotizing Enterocolitis by how much?

A

15-20%

98
Q

T/F
There have been modest to good results in probiotic treatment for gingivitis, halitosis, dental caries, and periodontal disease.

A

True

*periodontal hardest to carry out, in vivo animal exp’s promising

99
Q

What is a common probiotic species influential of a healthy mouth (or lack of caries)?

A

Lactobacillus acidophilus

100
Q

T/F

Oral administration of Lactobacillus acidophilus in the 1st year of life reduced caries 9 years later by half.

A

True

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