510-10

Question 1

What are the two models of tooth type determination

Answer 1

Field Model

Clone Model

Question 2

Describe the Field Model

Answer 2

distinct overlapping fields of ectomesenchymal cells express very particular sets of HOMEOBOX genes that results in tooth differentiation.

Question 3

Describe the Clone model

Answer 3

Ectomesenchymal cells (called the dental papillae) moves to the next tooth posterior at a certain developmental stage.

Question 4

What will the vestibular lamina become?

Answer 4

Space between cheek and gingiva.

Question 5

What are two types of invaginations in primary oral epithelium?

Answer 5

Vestibular and Dental Lamina

Question 6

What will the condensed bud of the dental lamina eventually form?

Answer 6

The amenoblasts

Question 7

At the Cap stage of development, what is the inside of the once bud region now called, and what is its function?

Answer 7

The Stellate Reticulum.

These cells pull fluid in, which expands the cells giving them their shape.

Question 8

What is the Enamel Knot and when does it appear?

Answer 8

It’s a condensed organizing center and appears at the Cap Stage.

Question 9

What are the 3 layers of the enamel organ?

Answer 9

IEE, OEE, and the Stellate Reticulum

cap stage

Question 10

What establishes the crown pattern and at what stage?

Answer 10

Established by the folding of the IEE at the Bell Stage

this is the DEJ

Question 11

What is the origination of enamel pearls?

Answer 11

It is the remnant of the dental lamina breaking off.

Question 12

What defines the Apposition Stage?

Answer 12

The growth of Dentin and Enamel from the DEJ

Question 13

What structure guides the development of the root?

Answer 13

Hertwig’s epithelial root sheath (HERS)

This is the junction of OEE IEE

Question 14

Where are the Odontoblast Processes found?

Answer 14

against the dentin at the DEJ

Question 15

Is the succedaneous lamina what’s left over from the Outer Enamel Epithelium?

Answer 15

I have no idea.

Question 16

What is it called when neural crest cells mix with mesoderm?

Answer 16

Ectomesenchyme

Question 17

What are the two main layers at 5-6 weeks in the jaw arches.

Answer 17

Primary epithelium and ectomesenchyme

Question 18

Where do the successional teeth develop in relation to the permanent teeth?

Answer 18

Lingually

Question 19

What are the 3 dental hard tissues and where do the come from?

Answer 19

Enamel - ameloblasts
Dentin - odontoblasts
Cementum - cementoblasts

Question 20

What is the distinguishing characteristic of an ameloblast in the secretory stage?

Answer 20

Tome’s Process

Question 21

What comprises 90% of enamel proteins

Answer 21

Amelogenins - they maintain the space between the rods.

Also have significant organizing and condensation role before withdrawing.

Question 22

What comprises 10% of enamel proteins?

Answer 22

nonamelogenins - includes ameloblastin and enamelin

Question 23

Describe the ameloblast ruffled and smooth stages

Answer 23

Alternate every 8 hours and depends on pH (more acidic lays down crystal in the ruffled stage)
80% of time spent in ruffled stage
20% time in smooth (higher pH) stage resorbing proteins (amelogenins)

Question 24

What is Perikymata

Answer 24

The surface expression of the Striae of Retzius - which is thought to be either rhythms of enamel production or ameloblast proliferation stages.

Question 25

What is the largest Striae of Retzius?

Answer 25

The neonatal line.

Question 26

What is the precursor to odontoblasts?

Answer 26

Ectomesenchymal cells

Question 27

How would you describe the incremental mineralization of dentin?

Answer 27

Globular and linear

Question 28

What are the two main types of dentin that pertain to the odontoblast process?

Answer 28

Peritubular and Intertubular

Question 29

Where are cementoblasts derived from?

Answer 29

Hertwig’s Epithelial Root Sheath (odontoblasts also come from here)