Micro of Dental Caires

Question 1

where do caries occur most

Answer 1

pits and fissures- most often in patients with low caries rate

Question 2

where are smooth surface and proximal caries often found

Answer 2

patients with high caries rate and often diet related

Question 3

root caries

Answer 3

found in pts with exposed root surfaces

Question 4

secondary caries

Answer 4

found at restorative margins

Question 5

explain the balance of demineralization and remineralization in health

Answer 5

lactic acid produced by bacteria dissolves enamel and salivary minerals are deposited in enamel causing no net change

Question 6

when does tooth structure loss occur

Answer 6

when body’s remineralization cant keep pace with acid production

Question 7

when do bacteria produce lactic acid

Answer 7

from glycolysis of sugars

Question 8

what does lactic acid do

Answer 8

drops pH and dissolves tooth minerals

Question 9

what happens to tooth surface at initial demineralization

Answer 9

tooth surface is stabilized by salivary pellicle proteins but demineralization occurs subsurface leaving a thin enamel shell

Question 10

when does cavitation occur

Answer 10

when subsurface demin becomes too severe and thin enamel shell is broken

Question 11

once cavitation occurs what is no longer possible

Answer 11

biologic repair is no longer possible once enamel shell is broken

Question 12

what is stronger and why? remineralized tooth structure or virgin enamel

Answer 12

remineralized tooth structure is stronger bc it has F incorporated in HA

Question 13

name 5 properties of caries causing bacteria

Answer 13

attach and form biofilm
produce acid (acidogenic)
tolerate acid (aciduric)
continue to produce acid at low pH
survive famine between meals by using fermentable sugars and storing polysaccharides

Question 14

is biofilm organization important to cause caries?

Answer 14

YES biofilm holds a diverse set of species that work together to produce conditions that are caries causing

Question 15

what are the 3 species that initiate caries

Answer 15

S mutans (as well as other streps).
Veillonella
and AA

Question 16

what species are responsible for caries progression

Answer 16

S mutans, L casei, rhamnosus, gassera, fermentum

bifido and scardovia

Question 17

what are the most common supra gingival organisms

Answer 17

strep! difficult to distinguish between the different streps

Question 18

describe the 3 important points of S mutans

Answer 18

primary caries pathogen
gram + cocci facultative
ferments carbs

Question 19

describe biofilm behavior of S mutans

Answer 19

attaches to S sanguinis

make ECM polysaccharide

Question 20

what is S mutants protected by

Answer 20

self protect by excretion of lactate well adapted for feast or famine

Question 21

what make S mutans a good scavenger during famine

Answer 21

good storage mechs, can maintain energy and low pH

Question 22

what does fluoride do to S mutants

Answer 22

F interferes with transport and intracellular processes of S mutans

Question 23

how are S mutans good for the host

Answer 23

S mutants protect against B hemolytic or other pathogenic streps and produces lactate and bacteriocins

Question 24

What is S sobrinus called and who is it related to

Answer 24

S sobrinus termed MS, related to S mutans

Question 25

Is S sobrinus associated with caries?

Answer 25

S sobrinus is strongly associated with caries but found at lower numbers than S mutans

Question 26

What is the earliest acquired bacteria that is not cariogenic and what is it bound by

Answer 26

S mitis= earliest acquired oral bacteria bound by salivary amylase and NOT cariogenic

Question 27

Where is S sanguinis found and describe it

Answer 27

S sanguine found in healthy plaque its gram + cocci facultative

Question 28

Describe S Sanguinis action with biofilm

Answer 28

S sanguinis is a good initial colonizer of pellicle coated tooth surfaces attaching via adhesins

Question 29

describe the metabolic and acid ways of S sanguinis

Answer 29

S sanguinis ferments carbs and proteins producing lactic acid at high pH can survive without sugar using the arginine hydrolase pathway raising pH

Question 30

what is often a cause of infective endocarditis (IE)?

Answer 30

S sanguinis

Question 31

Describe the bio of S salivarius

Answer 31

S salivarius has tongue and tooth niches associated with carries, in saliva but DOES NOT grow there

Question 32

Describe bio of AA

Answer 32

saccharolytic, acidogenic, filamentous, gram + | anaerobic or facultative

Question 33

what may contribute to root caries

Answer 33

AA

Question 34

what may be important in early stages of enamel caries

Answer 34

AA

Question 35

Describe bio of Veilonella

Answer 35

DOES NOT ferment carbs ferments lactate!! raises pH gram - anaerobic

Question 36

How does Veilonella contribute to caries?

Answer 36

Veilonella ferments lactate produce by streps which raises the pH thus helping pathogenic organisms survive and continue producing acid

Question 37

what is important in established and deep caries

Answer 37

Lactobacilli

Question 38

describe bio of lactobacilli

Answer 38

Lactobacilli is gram + rod | anaerobic, saccharolytic, acidogenic

Question 39

what may be important in deep caries that is a gram + rod that is anaerobic saccharolytic and acidogenic

Answer 39

Bifidobacterium and scardovia

Question 40

S sanguinis binds to pellicle via what

Answer 40

via specific adhesins

Question 41

S mutans binds to S sanguinis via what

Answer 41

via specific adhesins

Question 42

S mutan elaborates ECM from what

Answer 42

ECM from polysaccharide= glucan

Question 43

how does S mutans bind to glucan

Answer 43

via glucan binding proteins

Question 44

aciduric means what

Answer 44

bacteria can survive low pH so acid TOLERANT

Question 45

acidogenic means what

Answer 45

bacteria can lower pH | SO ACID PRODUCING!

Question 46

who can ferment sugars at low pH S sanguinis or S mutans

Answer 46

S mutans ferments sugars better at low pH than S sanguinis does

Question 47

what do healthy bacteria do

Answer 47

grow and make acid at high pH stops at LOW pH

Question 48

what do caries bacteria do

Answer 48

grow and make acid at LOW pH

Question 49

what do S mutans do in response to environmental exposure changes

Answer 49

S mutans will change gene expression thus making them more resistant to O2, higher pH and UV, enhances glycolysis causes S mutans to be more acid tolerant and produce more acid

Question 50

what is more important to caries short or long term sugar exposure

Answer 50

LONG term is more carious

Question 51

Low pH plaque due to inc sugar and carbs consumption does what

Answer 51

more favorable for S mutans than S sanguinis thus removing protective check from alkali generating organism like S sanguinis causing more acid to be produced thus lowering pH more thus demineralizing more thus deselecting for healthy bacteria more

Question 52

Describe the acquisition of S mutans

Answer 52

S mutans are usually acquired around 26 months (window of infectivity) from caregivers or others

Question 53

Caries vaccines to S mutans target what

Answer 53

glucosyl transferase and binding proteins

Question 54

what passive immunity approaches are under way for caries vaccines

Answer 54

ABs in tobacco plants, in immunized cows,

Question 55

Active immunity vaccines for carries include

Answer 55

mucosal vaccination for active immunity adjuvants required to elicit much response

Question 56

what is replacement therapy

Answer 56

replacement of carious wild type S mutans with genetically engineered non lactate producing strain

Question 57

what are stamps

Answer 57

Stamps are pheromone or AB guided antimicrobials that kill only targeted species