EX1; Odontogenesis

Question 1

*The formation of tooth tissue from stem cells originates in which germ layer

Answer 1

ectoderm

Question 2

When does odontogenesis begin

Answer 2

the 6th embryonic week

Question 3

What are the two basic tissues that arise from the ectoderm germ layer involved with tooth development

Answer 3

epithelium and mesenchyme

Question 4

This is the formation of dentin

Answer 4

dentinogenesis

Question 5

This is the formation of enamel

Answer 5

amelogenesis

Question 6

This is the formation of cementum

Answer 6

cementogenesis

Question 7

What is the order in which tooth tissue from

Answer 7

dentin
enamel
cementum

Question 8

What are the epithelial stages

Answer 8

epithelial dental lamina
epithelial bud
epithelial cap
epithelial bell (organ)

Question 9

What does the epithelial tissue develop within

Answer 9

a mesenchymal tissue environment

Question 10

What is the tooth germ stage

Answer 10

odontogenic epithelial and mesenchymal tissue combine inducing specificity to become the formative cells or dentin, enamel, cementum, and pulp

Question 11

*What are the three parts of the tooth germ

Answer 11

enamel bell (organ)
dental papilla
dental follicle

Question 12

*What tissues make up the parts of the tooth germ

Answer 12

enamel bell (organ) = epithelium
dental papilla and follicle = mesenchyme

Question 13

During which week do the vestibular and primary dental lamina from

Answer 13

6th embryonic week

Question 14

Which arch is a half a week behind the other in terms of development

Answer 14

maxillary is a 1/2 week behind the mandible

Question 15

This invagination of epithelium descending into the mesenchyme appears along the facial aspect

Answer 15

vestibular lamina

Question 16

This invagination of epithelium descending into the mesenchyme appears along the lingual aspect

Answer 16

primary dental papilla

Question 17

True or False
Upon development, the vestibular and primary dental lamina continue posteriorly within the mesenchyme as continuous epithelial bands

Answer 17

True

Question 18

What occurs in the center to the vestibular lamina

Answer 18

cell death; leaving the space as the vestibule

Question 19

What do cells arising from the primary dental lamina (primary and secondary) become

Answer 19

odontogenic epithelial part of a tooth germ

Question 20

Cells at the deep end of the primary dental lamina where a tooth is destined to be will develop into what

Answer 20

epithelial “knobs” or epithelial bud

Question 21

Each epithelial bud is surrounded by what

Answer 21

mesenchymal tissue

Question 22

When do the primary buds of central incisors form

Answer 22

6 weeks in utero

Question 23

When do primary buds of second molars form

Answer 23

8 weeks in utero

Question 24

When do permanent buds of first molars form

Answer 24

4 months in utero

Question 25

When do permanent buds of central incisors form

Answer 25

5 months in utero

Question 26

When do permanent buds of second molars form

Answer 26

10 months postnatally

Question 27

When do permanent buds of third molars form

Answer 27

5 years postnatally

Question 28

A total of how many epithelial buds arise from the primary dental lamina

Answer 28

16; 10 primary teeth and 6 permanent molars

Question 29

On which side of the primary dental lamina does the secondary dental lamina arise

Answer 29

lingual

Question 30

What specific structure is located in the epithelial cap

Answer 30

enamel knot

Question 31

What is the purpose of the enamel knot

Answer 31

it is a concentration of epithelial cells that is the signaling center determining if the tooth will develop into an anterior or posterior tooth

Question 32

What does the epithelium arrange into during the bell (organ) stage

Answer 32

4 distinct cell layers given names according to position within the bell and the cell morphology

Question 33

What are the four distinct epithelial cell layers of the enamel organ

Answer 33

inner epithelial layer stratum intermedium stellate reticulum outer epithelial layer

Question 34

Where does the secondary dental lamina arise from

Answer 34

primary dental lamina (NOT the oral epithelium)

Question 35

This is an epithelial enamel organ and a closely associated ectomesenchymal tissue that is continuous from around the epithelium to within the epithelium

Answer 35

tooth germ

Question 36

*What does the inner epithelial cells differentiate into

Answer 36

ameloblasts

Question 37

After the formulation of enamel, the ameloblasts along with other layers of the enamel organ come together over the surface of the enamel as what

Answer 37

a protective structure; reduced enamel epithelium

Question 38

*What do the undifferentiated (stem) cells of the dental papilla become

Answer 38

odontoblasts fibroblasts reserve cells

Question 39

What tissue does the dental papilla become

Answer 39

pulp

Question 40

*What do the undifferentiated (stem) cells of the dental follicle become

Answer 40

cementoblasts fibroblasts osteoblasts reserve cells

Question 41

What tissue does the dental follicle become

Answer 41

periodontal ligament of the periodontium

Question 42

The enamel organ is attached to both mesenchymal parts of the tooth germ via what

Answer 42

a basal lamina

Question 43

What occurs at the cervical loop of the enamel organ

Answer 43

where the inner and outer cell layers merge

Question 44

When the inner and outer epithelial layers merge at the cervical loop, they form what

Answer 44

a double epithelial layer celled Hertwigs epithelial root sheath

Question 45

What is the function of Hertwig's epithelial root sheath

Answer 45

determines root dentin outline | determines number of root canals of tooth

Question 46

What parts of the tooth germ are avascular or vascular

Answer 46

``` avascular = enamel organ vascular = dental papilla and follicle ```