Lecture 4 - Fluoride & Caries

Question 1

Enamel is laid down by…

Answer 1

ameloblasts

Question 2

During the _________ stage, the ameloblasts lay down the protein matrix for the rod crystal structure and the rods begin to form.

Answer 2

secretory

Question 3

During the __________ maturation stage, the ameloblasts fill in the crystal structure with mineral.

Answer 3

pre-eruptive

Question 4

Very high physiologic levels of fluoride during the secretory stage can cause _______ and this condition is called _______.

Answer 4

pitting

fluorosis

Question 5

Chronically, moderately high levels of fluoride during the _________ maturation stage causes disruptions in crystal formation (chalky whiteness and weakness of enamel). This is very common.

Answer 5

pre-eruptive

Question 6

T/F

There is no benefit from fluoridated water before tooth eruption.

Answer 6

True

Question 7

Fluoridation must continue _________ ____ in order to continue its benefits.

Answer 7

throughout life

Question 8

The effects of water fluoridation are ________.

Answer 8

topical

Question 9

Fluorosis risk is _________ by ingestion.

Answer 9

increased

Question 10

________ supplementation still officially recommended for high risk children.

Answer 10

Systemic

Question 11

Enamel composition is __% mineral (HA), __% water, and _% organic matrix.

Answer 11

87
11
2

Question 12

Newly formed crystals in a young tooth usually contain what 3 impurities?

Answer 12

carbonate
sodium
other ions

Question 13

In what process is the HA crystal perfected in a tooth when bathed in saliva (Ca++ and PO4) and exposed to fluoride?

Answer 13

post-eruptive enamel maturation

Question 14

In post-eruptive enamel formation, phosphate replaces ________, calcium replaces ________, and fluoride replaces _________. These replacements make HA less soluble (stronger).

Answer 14

carbonate
sodium
hydroxyl

Question 15

T/F

Young teeth are more susceptible to caries because post-eruptive maturation strengthens them over time.

Answer 15

True

Question 16

HA dissolves if pH drops below ___.

Answer 16

5.5

Question 17

What prevents the dissolving of calcium ions?

Answer 17

Fluoride ions

Question 18

T/F

Fluorhydroyxapatite (FHA) is less soluble than HA making enamel stronger.

Answer 18

True

Question 19

T/F
Lactic acid causes dissolution of enamel mineral that diffuses to the surface where reaction with fluoride causes formation of FHA.

Answer 19

True

Question 20

T/F

Fluoride diffuses well into the body of a lesion.

Answer 20

False
Fluoride does NOT diffuse well into the body of a lesion, because it reacts before it gets there with the outer layers to form FHA

Question 21

Subsurface HA is _______ while FHA is ______ in the surface layers.

Answer 21

dissolved

formed

Question 22

Whitespot lesions can have very high fluoride concentrations on their surface because of _____-_____ cycles.

Answer 22

demin-remin

Question 23

T/F

Areas covered by plaque have higher fluoride levels.

Answer 23

True

Question 24

T/F
Worn areas (abrasion, erosion) contain low levels of fluoride.

Answer 24

True

Question 25

What 4 things increase CaF2 deposition?

Answer 25

- increasing concentration of fluoride - increasing exposure time - lowering pH - protecting- limit rinsing or cover with varnish

Question 26

Saliva is supersaturated with what two molecules which prevent teeth from dissolving?

Answer 26

calcium | phosphate

Question 27

T/F | Fluorosis can occur during any stage of life.

Answer 27

False | Fluorosis can only occur when teeth are developing

Question 28

T/F | Fluoride levels are dependent on daily intake and bone stores.

Answer 28

True | There are no homeostatic mechanisms to control F concentration anywhere in the body

Question 29

T/F | Mild fluorosis is perceived as attractive by most people because the increase in enamel porosity appears chalky white.

Answer 29

True

Question 30

Which teeth are at the greatest risk of fluorosis and during what age range?

Answer 30

Upper central incisors | 15-30 months old

Question 31

T/F | Bacteria do NOT develop resistance to fluoride.

Answer 31

True

Question 32

What are the different methods of fluoride delivery?

Answer 32

- community-based water fluoridation - self-applied - professionally applied

Question 33

What are the three things on which the surface concentration of fluoride depends?

Answer 33

- topical exposure to F - acid exposure - wear

Question 34

If fluorosis is severe, enamel may be _______.

Answer 34

fragile

Question 35

Self-applied method of fluoride delivery has ____ frequency and ___ concentration.

Answer 35

high | low

Question 36

Professionally applied methods of fluoride delivery has ___ frequency and ____ concentration.

Answer 36

low | high

Question 37

When fluoride concentration is >100 ppm, what is deposited on tooth surface?

Answer 37

CaF2

Question 38

What amount of ppm of fluoride is safe and typically the amount found in OTC toothpaste?

Answer 38

1000 ppm

Question 39

Prescription toothpaste is available at what ppm?

Answer 39

5000 ppm

Question 40

T/F | There is no relationship between the fluoride concentration and caries benefit.

Answer 40

False | The higher the fluoride concentration, the better the toothpaste, but too much can lead to fluorosis

Question 41

T/F | There is no relationship between the amount of toothpaste and caries benefit.

Answer 41

True | It's not how much you use, but how much fluoride is present

Question 42

Fluoride supplements (ingesting fluoride) are really only recommended for ____ _____ patients.

Answer 42

high risk | not supported by evidence

Question 43

What is the typical concentration of fluoride in an OTC fluoride rinse?

Answer 43

0.02% (200 ppm)

Question 44

T/F | OTC rinses have shown to be as effective as toothpaste because you don't rinse.

Answer 44

True

Question 45

What two types of professional products are most often used due to comfort to the patient?

Answer 45

Foams and varnishes