Lecture 3- Caries microbiology

Question 1

most common sites for caries, usually found in low risk patients

Answer 1

pit and fissure

Question 2

which sites are less common, often diet related and found in patients with mod to high risk for caries

Answer 2

smooth surface and proximal

Question 3

… caries are found in patients with exposed root surfaces (sequelae of periodontitis)

Answer 3

root

Question 4

… caries are those found at restoration margins

Answer 4

secondary

Question 5

… produced by bacteria dissolves mineral from enamel

… are deposited on enamel

No net change occurs

Answer 5

lactic acid

salivary minerals

Question 6

bacteria in biofilms on surface of tooth produce …. from ….

Answer 6

lactic acid

glycolysis of sugars

Question 7

what does lactic acid do to the tooth

Answer 7

drops pH and mineral matrix of tooth dissolves

Question 8

tooth surface is stabilized by …. so initial demin. is subsurface, leaving a thin shell of enamel overlying body of lesion

Answer 8

pellicle proteins

Question 9

…. occurs when subsurface demineralization becoms too severe or extraordinary force is applied to surface

Answer 9

cavitation

Question 10

…. of lesion is possible as long as surface is retained. once cavitation occurs, biological repair is no longer possible

Answer 10

remineralization

Question 11

T/F remineralized tooth structure is stronger than virgin enamel

Answer 11

true (because of incorporation of fluoride into hydroxyappatite crystal structure)

Question 12

properties of caries-causing bacteria (5)

Answer 12

attach and form biofilm
produce acid (acidogenic)
survive acid (aciduric)
produce acid at low pH
survive "famine" btn meals

Question 13

how do caries-causing bacteria survive famine btn meals?

Answer 13

use multiple fermentable sugars at low concentrations

accumulate

Question 14

bacteria involved in caries initiation

Answer 14

streptococcus mutans

other strep, S. sobrinus, s. salivarius

veillonella

actinomyces

Question 15

bacteria involved in caries progression

Answer 15

s. mutans

lactobacillus casei, rhamnosus, gasseri, fermentum

bifidobacterium and scardovia

Question 16

… is the primary caries pathogen, it is gram- … cocci

Answer 16

S. mutans

positive

Question 17

S. mutans ferments…

Answer 17

carbohydrate (only nutrient source)

Question 18

Is S. mutans aerobic, anaerobic or facultative?

Answer 18

facultative

Question 19

S. mutans biofilm behavior?

Answer 19

attaches to S. sanguinis and makes extracellular polysaccharide matrix

Question 20

S. mutans is well adapted for … or …

Answer 20

feast or famine

Question 21

S. mutans has … … during feast time and is self-protected by excretion of …

Answer 21

active transport

lactate

Question 22

S. mutans is a good .. during famine

Answer 22

scavenger

Question 23

S. mutans has good … mechanisms

Answer 23

storage

Question 24

… is closely related to S. mutans and they are collectively termed “ …”

Answer 24

S. sobrinus

Mutans streptococci

Question 25

S. sobrinus is strongly associated with ... but is usually found in lower numbers than ...

Answer 25

caries S. mutans

Question 26

... is ubiquitous and is the earliest acquired oral bacteria

Answer 26

S. mitis

Question 27

.... is bound by salivary amylase and most strains are NOT cariogenic

Answer 27

S. Mitis

Question 28

... is found in healthy non-cariogenic plaque and is a good initial colonizer of pellicle-coated tooth surface

Answer 28

S. sanguinis

Question 29

Is S. sanguinis gram positive or negative?

Answer 29

positive

Question 30

Is S. sanguinis aerobic, anaerobic, or facultative

Answer 30

facultative

Question 31

... attached via adheins and adheres well

Answer 31

S. sanguinis

Question 32

... ferments carbs and proteins and can survive without sugar

Answer 32

S. sanguinis

Question 33

... produces lactic acid at high pH but not at low pH

Answer 33

S. sanguinis

Question 34

... may be protective against caries

Answer 34

S. sanguinis

Question 35

... is often the causative agent of IE

Answer 35

S. sanguinis

Question 36

What is the pathway used by S. sanguinis to raise the pH?

Answer 36

arginine hydrolase pathway | arginine--> urea--> NH3

Question 37

... is detected in saliva but actually grows on tooth and tongue

Answer 37

S. salivarius

Question 38

T/F S. salivarius is associated with caries

Answer 38

true

Question 39

Some strains of ... make bacterocins that prevent S. pyogenes colonization (probiotic)

Answer 39

S. salivarius

Question 40

... may contribute to root caries and may be important in early stages of enamel caries

Answer 40

Actinomyces

Question 41

Is actinomyces gram positive or negative

Answer 41

positive

Question 42

is actinomyces anaerobic, aerobic, or facultative

Answer 42

anaerobic/facultative

Question 43

Veillonella does not ferment carbs, it ferments...

Answer 43

lactic acid

Question 44

Veillonella can protect against ... or help acidogenic community members survive

Answer 44

acid

Question 45

Veillonella is gram ...

Answer 45

negative

Question 46

is veillonella anaerobic or facultative

Answer 46

anaerobic

Question 47

casei, rhamnosus, gasseri and fermentum are all

Answer 47

lactobacilli

Question 48

lactobacilli are important in ... lesions

Answer 48

deep/ established

Question 49

lactobacilli can cause some of the really ... decay

Answer 49

severe (late stage caries when its so acidic that s. mutans cannot survive)

Question 50

targets of possible vaccines for s. mutans

Answer 50

glucosyl transferase and glucan binding proteins