Lecture 4: Fluoride and dental caries

Question 1

what is the ideal concentration of fluoride to minimize fluorosis?

Answer 1

1 ppm

Question 2

T/F there is no benefit from fluoridated water before tooth eruption

Answer 2

true

Question 3

what type of cells create/lay down enamel?

Answer 3

ameloblasts

Question 4

during the _____ stage, ameloblasts lay down protein matrix

Answer 4

secretory

Question 5

during the _____ stage, ameloblasts fill crystal structure with minerals

Answer 5

maturation

Question 6

high levels of F during the secretory stage causes

Answer 6

• pitting

- disturbances in form

Question 7

moderately high levels of F in the maturation phase causes

Answer 7

• disruptions crystal formation
• chalky whiteness
• weakness of enamel
• enamel may fracture or stain

Question 8

T/F little fluoride is incorporated into enamel during the pre-eruptive maturation process

Answer 8

true

Question 9

what is the enamel composition

Answer 9

• 87% mineral (hydroxyapetite)
• 11% water
• 2% organic matrix

Question 10

formula for hydroxyapetite

Answer 10

Ca-10, PO4-6, OH-2

Question 11

what are some impurities in young tooth

Answer 11

• carbonate
• sodium
• other ions

Question 12

what are some of the replacements caused by post-eruptive enamel matruation

Answer 12

• phosphate replaces carbonate
• calcium replaces sodium
• fluoride replaces hydroxyl

Question 13

Hydroxyapatite dissolves if pH drops below _____

Answer 13

5.5

Question 14

T/F acid continues to dissolve because H+ combines with PO4 and OH ions, le chatlier

Answer 14

true

Question 15

if the pH remains above _____, flurohydroxyapatite forms on the surface when hydroxyapatite dissolves in the subsurface

Answer 15

4.5

Question 16

T/F when pH raises above 5, F ions enhance remineralization of enamel and dentin

Answer 16

false, 5.5

Question 17

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

Answer 17

true

Question 18

T/F surface has more fluroride and less carbonate

Answer 18

true

Question 19

T/F outer enamel is more soluble than interior

Answer 19

false

Question 20

Areas covered by _____ have higher F levels

Answer 20

plaque

Question 21

when topical fluoride concentrations are ____, fluorhydroxyapatite is formed on the outermost layer of enamel

Answer 21

50 ppm

Question 22

when topical fluoride concentrations are _____, calcium fluoride precipitates

Answer 22

100 ppm

Question 23

T/F calcium fluoride provides temporary storage of F that is gradually dissolved

Answer 23

true

Question 24

CaF2 deposition is increased by

Answer 24

• increasing concentration of F
• increasing exposure time
• lowering pH
• protecting with limited rinsing or cover

Question 25

crystals do not grow due to _____ that coat the enamel surface

Answer 25

- salivary pellicle proteins | - tyrosine rich peptides, statherin, proline-rich proteins

Question 26

T/F fluorosis can only occur when teeth are developing

Answer 26

true

Question 27

T/F exposure to F during development is a major determinant of F levels in enamel

Answer 27

false

Question 28

fluorosis severity and incidence correlated with _____

Answer 28

amount of exposure

Question 29

what teeth are at greatest risk for fluorosis?

Answer 29

central incisors

Question 30

F- binds to sites that would normally bind ____ and inhibits enzymes and regulatory proteins

Answer 30

OH

Question 31

T/F bacteria can develop resistance to F

Answer 31

false

Question 32

what enzyme does F inhibit to stop the production of lactase?

Answer 32

enolase

Question 33

T/F fluoride reduces that enrichment of acid-tolerant species

Answer 33

true

Question 34

Optimum benefit of fluoride presence during _____ challenge

Answer 34

acid

Question 35

concentration of toothpaste in US

Answer 35

1000 ppm F

Question 36

3 types of fluoridated toothpaste available

Answer 36

- NaF2 - monofluorophosphate (MPF) - SnF2 (stannous fluoride)

Question 37

what concentration of toothpaste is available for Rx?

Answer 37

5000 ppm

Question 38

T/F there is a direct relationship between the amount of toothpaste and caries

Answer 38

false

Question 39

concentration of fluoride rinses

Answer 39

200 ppm, 25% reduction in caries

Question 40

composition of professional fluoridation

Answer 40

1.23% acidulated phosphate fluoride

Question 41

most effective professional product

Answer 41

- fluoride varnish - 2.2% F as NaF - 40% reduction in caries

Question 42

T/F water fluoridation deposits CaF2 on the surface of the tooth

Answer 42

false

Question 43

T/F ingestion of fluoride carries risk of fluorosis

Answer 43

true