D'Souzza tooth development

Question 1

The dental lamina has two parts

Answer 1

Primary epithelial band

Ectomesenchyme

Question 2

What causes thickening of the primary epithelial band?

Answer 2

Cell proliferation

Question 3

Dental placode def

Answer 3

Epithelial structure that forms along dental lamina and rapidly invades the underlying mesenchyme

Question 4

Primary epithelium aka

Answer 4

Oral epithelium

Question 5

The part of epithelium that starts to go down into ectomesenchyme is known as

Answer 5

Dental lamina

Question 6

Six stages of crown development

Answer 6

1) Initiation
2) Bud Stage
3) Cap Stage
4) Bell Stage
5) Apposition Stage
6) Maturation Stage

Question 7

In what stage(s) does morphogenesis occur

Answer 7

Cap Stage

Early Bell Stage

Question 8

After the dental lamina, then what happens?

Answer 8

The dental bud is formed

Question 9

Where are buds produced and how many are made?

Answer 9

At 10 locations on EACH dental lamina, buds are produced

Question 10

Each bud is a precursor for what?

Answer 10

An enamel organ for each deciduous tooth

Question 11

What enzyme starts to cause the inductive influence of dental epithelium?

Answer 11

BMP 4

Question 12

Induction def

Answer 12

Process whereby one tissue changes the development of surrounding tissues

Question 13

In tooth development _______ stimulates the pre-dental ectoderm to produce ____-

Answer 13

Lef - 1

Fgf - 8

Question 14

Fgf - 8 induces underlying mesenchyme to express what?

Answer 14

Pax 9

Msx - 1

Question 15

BMP 2 and BMP 4 inhibit what?

Answer 15

Fgf - 8

Question 16

What happens during Cap Stage

Answer 16

1) Unequal proliferation shaping a cap form
2) Ectomesenchyme cells become Dental papilla and Dental Sac
3) Successional dental lamina forms on lingual side of dental lamina
3. 5) Successional dental lamina will give rise to the enamel organs of the permanent teeth

Question 17

Tooth germ def

Answer 17

Enamel organ + Dental Papilla + Dental Sac

Question 18

Enamel Niche def

Answer 18

Structure created by plane of section cutting. Mesenchyme appears to be surrounded by dental epithelium

Question 19

During Bell Stage, order of layers fro outside in

Answer 19

1) Outer Cells of dental papilla
2) Basement membrane
3) IEE
4) Stratum Intermedium
5) Stellate Reticulum

Question 20

What happens during Bell Stage

Answer 20

• 1) Differentiation of 4 layers.
  2) Cervical loop appears
  3) Dental Papilla differentiates into Outer and Inner dental papilla

Question 21

OEE Functon

Answer 21

Protective Barrier for enamel organ

Question 22

Stellate Reticulum Fencution

Answer 22

Supports Enamel Production

Question 23

Stratum Intermedium Function

Answer 23

Supports enamel mineralization - alkaline phosphataswe

Question 24

IEE Funtion

Answer 24

Differentiate into amelobasts

Question 25

What happens during Apposition Stage

Answer 25

1) Organic Matrix of enamel and dentin are laid down and initial calcification happens
2) Series of reciprocal inductions

Question 26

Order of Apposition reciprocal induction

Answer 26

1) Mesenchyme > IEE > Preameloblasts
2) Preameloblasts induce outer DP Cells > preodontoblasts> odontoblasts
3) DEJ FOrms after disintegration of basement membrane
4) Odontoblasts leave DEJ leaving odontoblastic processes with predentin
5) Space that contains process is called a “dentinal tubule”
6) Odontoblasts begin to secrete organix matrix of dentin aka predentin. Predentin casues IEE>preameloblasts>ameloblasts
7) Ameloblasts retreat from DEJ as enamel matrix is deposited. Enamel Matrix instantly calcifies to 25% full mineralizaition
8) Prism-less enamel is made by early secretory ameloblasts
9) Enamel Prisms are formed by Tomes processes of late secretory ameloblasts

Question 27

Ameloblast Lifecycle

Answer 27

1) Inner Enamel Epithelial Cell
2) Preameloblast
3) Initial Secretory Ameloblast
4) Secretory Ameloblast
5) Smooth-ended maturation ameloblast
6) Ruffle - ended ameloblast
Protective Ameloblast

Question 28

Preameloblast funtion

Answer 28

• Cell reverses polarity

Question 29

Initial Secretory ameloblast function

Answer 29

No Tomes process

Prismless enamel

Question 30

Secretory ameloblast

function

Answer 30

Tomes process

Enamel Prism

Question 31

Smooth ended Ameloblast Function

Answer 31

Removal of protein and water

Question 32

Ruffled ended maturation ameloblast funtion

Answer 32

Intro of inorganic material

Question 33

Protective ameloblast function

Answer 33

enamel cuticle

Question 34

Which way does apposition and maturation occur? Where does it start?

Answer 34

Starts at cusp/incisal edge and progresses in a cervical direction

Question 35

What happens in maturation Stage with enamel

Answer 35

1) Secretory ameloblasts lose Tomes Processes
2) Amloblasts differentiate into protective ameloblasts
3) Enamel cuticle secreted
4) Ameloblasts attach to enamel surface via hemidesmosomes (Epithelial Attachment)
5) Reduced enamel Epithelium forms once enamel s fully mature

Question 36

What is REE made of

Answer 36

OEE
IEE
Remnants of other two layers

Question 37

What happens in maturation Stage of Dentin

Answer 37

1) Dentin mineralizes as ts deposited
2) Initial mineralizatin produces globular dentin
3) Mantle Dentin Made
4) Circumpulpal Dentin made

Question 38

What is Mantle dentin

Answer 38

Dentin with collagen fibers perpendicular to DEJ

Dentin with high mineral content

Question 39

What is Circumpulpal Dentin

Answer 39

Dentin with collagen fibers parallel to DEJ

Low mineral Content

Question 40

Where does Hertwigs Root Sheath come from?

Answer 40

Cervical Loop