enamel structure

Question 1

rod enamel is formed during

Answer 1

secretory phase

-around tomes processes

Question 2

enamel crystals are what shape

Answer 2

hexagonal

Question 3

within the rod, the individual crystallites at certain angles are

Answer 3

not parallel

Question 4

the different orientations of enamel prevent

Answer 4

crack propagation and withstand forces of cyclic loading

Question 5

what is the less mineralized form of HAP

Answer 5

amorphous calcium phosphate (ACP)

Question 6

surface enamel is

Answer 6

permeable to ions and small molecules

Question 7

rods are ____ to the DEJ

Answer 7

perpendicular

Question 8

why do cross striations form on growing rods

Answer 8

due to cyclical activity of enamel growth

-regulated by circadian rhythms

Question 9

tree growth rings of teeth (inside enamel)

Answer 9

retzius striae

Question 10

enamel surface

Answer 10

perikymata

Question 11

what can be seen at the cuspal tip

Answer 11

gnarled enamel

Question 12

enamel spindles and tufts location

Answer 12

extend from the DEJ into enamel

Question 13

enamel spindles

Answer 13

• odontoblast process

- increase susceptibility to caries and sensitivity

Question 14

enamel tufts

Answer 14

• protein-rich areas

- strengthen bond between dentin and enamel

Question 15

residual protein (ameloblastin)

Answer 15

surrounds the rods and forms a sheath

Question 16

what does the sheath around the rod do

Answer 16

1. doesnt etch as fast as core (creates a jagged surface, good for resto)
2. lubricates adjacent rods (limited elastic movement)

Question 17

nanocrystallites also have

Answer 17

core-shell structure

Question 18

higher Mg in core

Answer 18

higher solubility

Question 19

2 resin tages that interlock with etch-pits

Answer 19

macrotags and microtags

Question 20

macrotags

Answer 20

space surrounding enamel prisms

Question 21

microtags

Answer 21

• result from resin infiltration into core

- really helps retain resto