2/7/17 Dr. Dsouza Test #2 Tooth Development

Question 1

In the bell stage of development the continued differentiation of the enamel organ produces what four distinct layers?

Answer 1

• Outer enamel epithelium
• Stellate reticulum
• Stratum intermedium
• Inner enamel epithelium

Question 2

What is the portion of tooth development is responsible the all the future periodontium?

Answer 2

-Dental follicle

Question 3

What is the cervical loop?

Answer 3

The junction of the OEE and IEE

Question 4

What is the function of the outer enamel epithelium?

Answer 4

-Protective barrier for enamel organ

Question 5

What is the function of the stellate reticulum?

Answer 5

-Supports enamel production

Question 6

What does the IEE differentiate into?

Answer 6

-ameloblasts

Question 7

What is the function of the stratum intermedium?

Answer 7

-supports enamel mineralization

Question 8

What does the DEJ form after?

Answer 8

-Disintegration of basement membrane

Question 9

What type of enamel is formed by early secretory ameloblasts?

Answer 9

-Prismless enamel

Question 10

What type of enamel is formed by Tomes processes or late secretory ameloblasts?

Answer 10

-Enamel prisms

Question 11

Name the only ectodermally derived structure in the tooth?

Answer 11

-Enamel

Question 12

Apposition and maturation of dentin and enamel occur in increments from where?

Answer 12

-The cusp or incisal tip

Question 13

The apposition and maturation of dentin and enamel from the incisal or cusp tips occur in what direction?

Answer 13

-Cervical direction

Question 14

After the deposition and initial mineralization of enamel, what do secretory ameloblasts lose?

Answer 14

-Tomes process

Question 15

When does the Reduced enamel epithelium form?

Answer 15

-After enamel is fully matured

Question 16

What two layers can you find in the REE?

Answer 16

• OEE

- IEE

Question 17

When does dentin mineralize?

Answer 17

-AS it is deposited

Question 18

The initial mineralization of dentin is in the form of globules ultimately producing what?

Answer 18

-Globular dentin

Question 19

What is the initial layer of dentin next to the DEJ called?

Answer 19

-Mantle dentin

Question 20

What is remaining dentin around the pulp called?

Answer 20

-Circumpulpal dentin

Question 21

In the circumpulpal dentin what direction are the collagen fibers in comparison to the DEJ?

Answer 21

-Parallel

Question 22

In the mantle dentin the collagen fibers are oriented in what direction to the DEJ?

Answer 22

-Perpendicular

Question 23

Which layer of dentin has higher mineral content?

Answer 23

-Mantle dentin

Question 24

What becomes Hertwig’s epithelial root sheath?

Answer 24

-Root Dentin

Question 25

When the Hertwig's epithelial root sheath detaches from root dentin and disintegrates what do they become?

Answer 25

-Epithelial rests of Malassez

Question 26

What is the organic matrix that cementoblasts secrete?

Answer 26

-Cementoid

Question 27

How do you get multiroot development?

Answer 27

The Hertwigs eipithelial roots sheath splits into two or three sheaths

Question 28

When the dental sac ectomesenchyme cells differentiate into fibroblasts what can they form?

Answer 28

-Periodontal ligament

Question 29

When the dental sac ectomesenchyme cells differentiate into osteoprogenitor cells what can they form?

Answer 29

-Osteoblasts to lay down alveolar bone

Question 30

Where do developing collagen fibers of the PDL become anchored?

Answer 30

-Alveolar bone

Question 31

What are five important molecules in embryonic development?

Answer 31

- TGF B family - Fibroblast GF family - Hedgehog protein - Wnt family - Negative regulators of BMP signalling

Question 32

What are protooncogenes?

Answer 32

-Normal genes which direct formation of various molecules

Question 33

What are the two theories of tooth development?

Answer 33

- Field Theory | - Clone Theory

Question 34

What does the field theory of development include?

Answer 34

-The tooth doesn't know what it is going to become until it gets to its "field" that "tell" it what to do

Question 35

At the Lamina and bud stage what is inductive?

Answer 35

-Dental epithelium

Question 36

At the Cap and Early Bell stages what is inductive?

Answer 36

-Dental papilla Mesenchyme

Question 37

In the later stages of tooth development such as the early bell stage what determines the shape of the tooth?

Answer 37

-Dental papilla mesenchyme

Question 38

If at the later stages of tooth development such as during the early bell stage and you take molar mesenchyme and incisal epithelium what will grow?

Answer 38

-Molar

Question 39

If at an early stage of tooth development such as the Bud Stage and you take a molar mesenchyme and an incisal epithelium what will grow?

Answer 39

-Incisal