Lecture 4 - Fluoride and dental caries

Question 1

T/F there is a benefit from fluoridate water before tooth eruption. To continue benefits, fluoridation must continue throughout life/

Answer 1

F - no benefit before tooth eruption

T

Question 2

T/F fluorosis risk is decreased by ingestion

Answer 2

F - increased

Question 3

What is enamel laid down by?

Answer 3

ameloblasts

Question 4

what happens during the secretory stage of enamel formation?

Answer 4

ameloblasts lay down protein matrix for rod crystal structure. rod formation begins

Question 5

what happens during maturation stage of enamel formation?

Answer 5

ameloblasts fill in crystal structure with mineral

Question 6

very high physiologic levels of fluoride during secretory stage can cause:

Answer 6

pitting and disturbances

Question 7

high levels of fluoride during maturation stage cause disruptions in crystal formation appearing as:

Answer 7

chalky whiteness and weakness of enamel

Question 8

T/F after eruption, weakened enamel may fracture and stain. A lot of fluoride is incorporated into enamel during pre-eruptive maturation process

Answer 8

T

F - little fluoride

Question 9

What is the composition of enamel?

Answer 9

87% hydroxyapatite
11% water
2% organic matrix

Question 10

impurities found in newly formed crystals in a young tooth are usually:

Answer 10

carbonate
sodium
other ions

Question 11

process where phosphate replaces carbonate, calcium replaces sodium and fluoride replaces hydroxyl is known as:

Answer 11

post-eruptive enamel maturation

Question 12

T/F
young teeth are less susceptible to caries
enamel maturation strengthens them over time

Answer 12

F - more susceptible

T

Question 13

At what pH does hydroxyapatite dissolve?

Answer 13

if pH is below 5.5

Question 14

fluorhydroxyapatite forms on surface when hydroxyapaite dissolves from subsurface at what pH when fluoride ions are available?

Answer 14

above 4.5

Question 15

at what pH do fluoride ions enhance remineralization of enamel and dentin?

Answer 15

above 5.5

Question 16

T/F presence of fluoride at low levels in solution is more beneficial than high concentrations incorporated into enamel

Answer 16

T

Question 17

T/F
surface has more fluoride and less carbonate
outer enamel is more soluble than interior

Answer 17

T

F - less soluble

Question 18

why do whitespot lesions have very high fluoride concentrations on their surface?

Answer 18

demin-remin cycles

Question 19

T/F areas covered by plaque have lower fluoride levels

worn areas contain low levels of fluoride

Answer 19

F - higher

T

Question 20

T/F when topical fluoride concentrations are low (50 ppm or less), fluorhydroxyapatite is formed on outermost layers of enamel

Answer 20

T

Question 21

when topical fluoride concentrations are above 100 ppm what precipitates?

Answer 21

calcium fluoride

Question 22

calcium fluoride is increased by:
1
2
3
4

Answer 22

1 increasing fluoride concentration (10000 ppm)
2 increasing exposure time (4 min)
3 lowering pH
4 protection - using rinsing or varnish

Question 23

T/F teeth dissolve when saliva is supersaturated with calcium and phosphate

Answer 23

F - teeth don’t dissolve

Question 24

T/F
plaque prevents access of saliva to enamel surface
in plaque biofilm, interbacterial fluid cannot have higher concentrations of calcium and phosphate leading to calculus formation

Answer 24

T

F - they can have higher concentrations

Question 25

when does fluorosis occur?

Answer 25

when teeth are developing

Question 26

levels of fluoride concentration are dependent on ___________ and _________________

Answer 26

daily intake

bone stores

Question 27

T/F
fluoride concentration in teeth is lowest on surface
surface concentration of fluoride is dependent on topical exposure to Fluoride, acid exposure and wear

Answer 27

F - highest

T

Question 28

Fluorosis is an increase in enamel porosity that appears ____________

Answer 28

chalky white

Question 29

what occurs post-eruptively due to staining and browning of exposed protein?

Answer 29

brown discoloration

Question 30

T/F fluorosis occurs during enamel maturation

fluorosis severity and incidence correlated with amount of exposure

Answer 30

T

T

Question 31

What kind of fluorosis is most attractive?

Answer 31

mild fluorosis

Question 32

T/F
risk of fluorosis occurs at any time
upper central incisors greatest risk is at 15-30 months

Answer 32

F - during development

T

Question 33

T/F
fluoride is highly concentrated in plaque
bacteria develop resistance to fluoride

Answer 33

T

F - they do not

Question 34

what are the 3 methods of fluoride delivery?

Answer 34

1 water
2 self applied (high freq, low conc.)
3 professionally applied (low freq. high conc)

Question 35

calcium fluoride is deposited on surface when concentration of fluoride is:

Answer 35

above 100 ppm

Question 36

fluoride release is enhanced by:

Answer 36

low pH

Question 37

water fluoridation produced a ___% reduction in tooth decay

Answer 37

50%

Question 38

T/F
no relationship between amount of toothpaste and caries
Brushing twice a day is better than once
rinsing after brushing is better

Answer 38

T
T
F - less rinsing is better

Question 39

OTC fluoride rinses produced a __% reduction in tooth decay

Answer 39

25%

Question 40

T/F
topical products deposit calcium fluoride on surface of tooth
during acid attack, CaF2 dissolves and increases remineralization and becomes fluorapatite

Answer 40

T

T

Question 41

T/F
water fluoridation deposits CaF2 on surface of tooth
ingestion of fluoride increases risk of fluorosis

Answer 41

F - it does not

T