Pchem

Question 1

If you have a cross section of enamel in an SEM, you will see that enamel is formed of _______ which are made up of ______

Answer 1

crystals, minerals

Question 2

what is the hardest tissue in the human body?

Answer 2

enamel

Question 3

what is the composition of enamel?

Answer 3

88% minerals
10% water
2% organic

Question 4

Characteristics of enamel? (vascularity, cellularity, permeability, vitality)?

Answer 4

Avascular
Acellular
Semi-permeable
non-vital

Question 5

______ is formed by dentinoblasts

Answer 5

Dentin

Question 6

pain and feeling in the dentin is from ______

Answer 6

dentinoblast

Question 7

what are crystals made up of?

Answer 7

Calcium, phosphate, hydroxide

Question 8

when do crystals become fully mineralized?

Answer 8

as soon the tooth erupts

Question 9

what are minerals that can be taken up by crystals?

Answer 9

Carbonate, Na+, F+

Question 10

Carbonate _______ solubility while Fluoride _____ solubility

Answer 10

increases, decreases

Question 11

HAp is made of what?

Answer 11

Ca, Phosphate, hydroxide

Question 12

enamel is mainly formed of ______

Answer 12

HAp

Question 13

what can replace Ca in HAp?

Answer 13

Mg, Na

Question 14

What can replace phosphate in HAp?
what about hydroxyl?

Answer 14

• carbonate can replace phosphate
• Carbonate and Fluoride can replace OH

Question 15

solubility increases by a factor of ____ per pH unit

Answer 15

10

Question 16

in FHAp, fluoride partially replaces what group?

Answer 16

OH

Question 17

In FAp what replaces what?

Answer 17

Fluoride completely replaces OH

Question 18

FAp dissolves at pH ______

Answer 18

4.5

Question 19

___________ means that all minerals have an inherent fixed solubility in water at any given temperature

Answer 19

minerals dissolution

Question 20

which 3 pathways can bacteria + sucrose go?

Answer 20

1. Extracellular polymer
2. intracellular polymer
3. lactic acid

Question 21

neutral saliva = ____ pH

Answer 21

6.5

Question 22

if you eat sugar, pH drops below _____ and it can take ________ mins for pH to go back to normal

Answer 22

5.5, 20-60

Question 23

the subsurface layer is a _______ thick well mineralized surface layer

Answer 23

20-50um

Question 24

how are caries and erosion different?

Answer 24

1. Caries:
   - Slower
   - have bacterial involvement
   - “Partial demineralization” (still have structure that other materials can precipitate on)
2. Erosion:
   - total loss of enamel
   - Faster
   - no bacteria
   - FAp/ HAp all gone

Question 25

bacteria causes ______ and occurs at ______ pH

Answer 25

caries, 4.5-5

Question 26

A non-cariogenic source causes _____ and always has a pH of ______

Answer 26

Erosion
less than 4

Question 27

________ is the loss of dental hard tissue due to direct dissolution by acids from nutrition, environment, or stomach that are NOT bacterial origin

Answer 27

Erosion

Question 28

can cupping be repaired?

Answer 28

no

Question 29

erosive substances have little or no _______

Answer 29

Ca and phosphate

Question 30

Solubility of enamel at pH 3 is_____x greater than at pH5

Answer 30

100x

Question 31

Dentin is hypermineralized tissue that has ____ minerals than enamel

Answer 31

LESS

Question 32

is dentin mineralized faster or slower than enamel when exposed? why?

Answer 32

FASTER, because it has less minerals

Question 33

______ activity in dentin removes collagenous protein

Answer 33

proteolytic

Question 34

________ respond to exogenous stimuli through deposition of minerals along and in dentinal tubules

Answer 34

Vital teeth (with a healthy pulp)

Question 35

at pH 6.5 what happens?

Answer 35

Remineralization/calculus formation, HAp: supersaturated, FHAp supersaturated

Question 36

at pH 5.5 what happens?

Answer 36

Caries, HAp: undersaturated, FHAp: supersaturated

Question 37

at pH <4 what happens?

Answer 37

Erosion, HAp & FHAp Undersaturated