(E1) 4 - Odontogenesis Pt II: Crown Formation

Question 1

Genetic disorder leading to abnormal enamel functions

Answer 1

Amelogenesis imperfecta

Question 2

Genetic disorders leading to abnormal dentin formation

Answer 2

Dentinogenesis imperfecta

Question 3

3 components of a tooth

Answer 3

Enamel
Dentin
Pulp

Question 4

Describe Enamel

Answer 4

Question 5

Describe Dentin

Answer 5

Question 6

When is size and shape of tooth set?

Answer 6

Cap stage

Question 7

In the crown stage, changes are associated with

Answer 7

• Amount and type of hard tissue mineralization
• Reduction of some tooth germ structures

Question 8

In the late bell stage, signals from the enamel knot cause what?

Answer 8

Question 9

Odontoblast differentiation occurs because of signals from ________

Answer 9

IEE

Question 10

What are the functions of mature odontoblasts?

Answer 10

Question 11

What is the first step in dentinogenesis?

Answer 11

Pre-Dentin Deposition

Question 12

Describe Primary Dentin

Answer 12

Question 13

When does secondary dentin form?

Answer 13

After eruption
- Includes radicular dentin and circumpulpal

Question 14

What is mantle dentin?

Answer 14

First pre-dentin to be secreted and mineralized (closest to the DEJ)

Question 15

What is the second stage of dentinogenesis?

Answer 15

Question 16

What is the third stage of dentinogenesis?

Answer 16

Question 17

Stages of Development: Crown Stage

What is the functional stage and morphological appearance?

Answer 17

Functional = Apposition
Morphological = Hard tissues of crown visible

Question 18

What are ameloblasts?

Answer 18

Ectoderm-derived epithelial cells of the inner enamel epithelium

Question 19

Where does the deposition of the dentin matrix begin and end?

Answer 19

Begins at the future cusps along DEJ, continues towards the cervical loop

Question 20

Crown Stage: Describe what is happening during the initiation of the crown stage.

Answer 20

Question 21

What is happening during ameloblast maturation?

Answer 21

Question 22

As reduction of the enamel organ occurs, what forms?

Answer 22

HERS

Question 23

What are the 4 stages of amelogenesis?

Answer 23

1 - Presecretory (inductive)
2 - Secretory
3 - Maturation
4 - Protective

Question 24

Amelogenesis: Describe what is happening in the Pre-Secretory stage.

Answer 24

Question 25

Amelogenesis: Describe what is happening in the Secretory stage.

Answer 25

Question 26

Amelogenesis: Describe what is happening in the Maturation stage.

Answer 26

Question 27

Amelogenesis: Describe what is happening in the Protective stage.

Answer 27

Question 28

Image of Amelogenesis

Answer 28

Question 29

Synthesis and secretion of Enamel ECM (secretory stage): What are the cells involved and the function?

Answer 29

Question 30

What are the types of secretory ameloblasts and what are the resulting types of enamel?

Answer 30

Question 31

Amelogenesis - Describe:

Answer 31

Question 32

How might a mutation in the genes responsible for encoding organic matrix proteins affect amelogenesis?

Answer 32

Question 33

Amelogenesis - Describe:

Answer 33

Question 33

Deposition and orientation of enamel crystals depend on the presence of a ___________

Answer 33

Tome’s process

Question 34

Describe Aprismatic enamel

Answer 34

Question 35

What are the 3 orientations of enamel crystals?

Answer 35

- Aprismatic - Prismatic/Rod enamel - Inter-prismatic/Interrod

Question 36

Amelogenesis - Describe:

Answer 36

Question 37

What are the 2 types of mature ameloblasts?

Answer 37

Ruffled and Smooth

Question 38

Amelogenesis: Function of ruffle ended cells

Answer 38

- incorporation of inorganic (mineral) content

Question 39

Amelogenesis: Function of smooth ended cells

Answer 39

- removal of organic material (proteins) and water by enzymatic digestion - changes in pH changes shape

Question 40

All hard tissue (bone, enamel, dentin, cementum) is deposited incrementally in successive layers by ____________

Answer 40

appositional growth (result - lines visible)

Question 41

Amelogenesis - Describe: (cells involved and function)

Answer 41

Question 42

What composes the reduced enamel epithelium?

Answer 42

Question 43

As tooth erupts, REE fuses with oral epithelium and becomes __________

Answer 43

junctional epithelium

Question 44

What two layers fuse together and form HERS?

Answer 44

IEE and OEE

Question 45

What does HERS signify?

Answer 45

Signifies the end of the crown and the start of root formation

Question 46

Describe Early Crown

Answer 46

Question 47

Describe Mid Crown

Answer 47

Question 48

Describe Late Crown

Answer 48

Question 49

Describe how you know when the crown is complete.

Answer 49