Odontogenesis

Question 1

what is odontogenesis

Answer 1

Formation of tooth tissues from stem cells originating in the ectoderm

Question 2

when does Odontogenesis begin

Answer 2

6th embryonic week

Question 3

what parts of the ectoderm are involved in tooth development

Answer 3

Epithelium and mesenchyme

Question 4

what tissue contains stem cells that become the specialized cels that form tooth tissues

Answer 4

Odontogenic tissues

Question 5

Fomation of dentin tissue

Answer 5

Dentinogenesis

Question 6

Formation of enamel tissue

Answer 6

Amelogenesis

Question 7

Formation of Cementum tissue

Answer 7

Cementogenesis

Question 8

Formation of pulp tissue

Answer 8

Pulpogenesis

Question 9

two histologic stages of odontogenesis

Answer 9

Epithelial stages

Tooth germ stages

Question 10

Epithelial stages

Answer 10

Epithelial dental lamina stage
Epithelial bud stage
Epithelial cap stage
Epithelial bell stage (enamal organ)

Question 11

when is the epithelium arranged in 4 distinct layers

Answer 11

At the bell stage

Question 12

what are the epithelial stages based on

Answer 12

Histologic shapes of epithelial tissues

Question 13

what happens in the tooth germ stage

Answer 13

the odontogenic and epithelial and mesenchymal tissues combine and cells of each induced specifically to become formative cells of dentin, enamel, cementum and pulp tissues

Question 14

the 3 parts of the tooth germ and the type of cells that make them up

Answer 14

Enamel organ (bell):
Dental papilla: mesenchym
Dental Follicle: mesenchyme

Question 15

the parts of the tooth germ give rise to

Answer 15

specialized cels that form tooth tissues

Question 16

when does the primary dental lamina stage occur

Answer 16

6th embryonic week

Question 17

what occures in the dental lamina stage

Answer 17

2 epithelial invagination in the lower anterior region of the lower jaw (upper happens later in the same week) decend into the ectomesenchyme

Question 18

what are the 2 bands formed in the primary dental lamina stage

Answer 18

Facial: vestibular lamina
Lingual: primary dental lamina

Question 19

what happens to the vestibular lamina

Answer 19

Cell death occurs in the cental of the vestibular lamina leading to the vestibular

Question 20

what happens to the primary dental lamina

Answer 20

Cells arisisng for the dental laminae become the odontogenic epithelial part of a tooth germ

Question 21

what happens in the epithelial bud stage

Answer 21

formation of epithelial buds at the deep end of the dental lamina

Question 22

what is the epithelial bud

Answer 22

epithelial knots where a tooth is too be formed at the deep end of the dental lamina

Question 23

what surrounds each epithelial bud

Answer 23

Mesenchymal tissue

Question 24

how are epithelial bud cells separated from the primary dental lamina

Answer 24

Not separated, they are continuous

Question 25

what separates the vestibular lamina from the the epithelial bud

Answer 25

Bands of epithelail cells

Question 26

when do priimary buds form

Answer 26

Cental incisors: 6 weeks in utero | Second molar: 8 weeks in utero

Question 27

when do permanent buds from

Answer 27

First molar: 4 months in utero Central incisors: 5 months in utero Second molar: 10 months postnatally third molar: 5 years postnatally

Question 28

how do 3rd molars look before year 5

Answer 28

look like a cyst

Question 29

where does the secondary lamina form

Answer 29

Behind the primary dental lamina

Question 30

why does the secondary dental lamina form

Answer 30

there is one for each succedaneous tooth

Question 31

is there a secondary dental lamina for perminant molars

Answer 31

NO

Question 32

what does the primary dental lamina give rise to

Answer 32

16 epithelial buds (10 primary and 6 permanent)

Question 33

what happens at the cap stage

Answer 33

Odontogenic epithelium is in the shape of a cap

Question 34

what is the enamel knock

Answer 34

Concentration of epithelial cells of the cap to serve as a signalling center - determines if the tooth will develop to become and anterior or posterior tooth

Question 35

where is mesenchym in the epithelial cup stage

Answer 35

In and outside of the epithelial cup

Question 36

what happens in the epithelial bell stage

Answer 36

Epithelial cap undergoes growth and develops into a bell shaped epithelial structure

Question 37

the other name for the peithelial bell

Answer 37

Enamel organ

Question 38

layers of the epithelial bell stage from inside to outside

Answer 38

Inner epithelial layer Stratum intermedium epithelial layer Stellate reticulum epithelial layer Outer epithelial layer

Question 39

how many secondary dental lamina form in each arch

Answer 39

10 in each arch( one for each succidaneous tooth)

Question 40

what does the secondary dental lamina arise from

Answer 40

The primary dental lamina (NOT THE ORAL EPITHELIUM)

Question 41

what parts of the tooth germ are vascularized

Answer 41

Enamel organ: no Dental papilla: yes Dental Follicle: yes

Question 42

what do the inner epithelial cells of the enamal organ differentiate into

Answer 42

Ameloblasts

Question 43

what are ameloblasts

Answer 43

Specialized epithelial cells

Question 44

what do the ameloblasts and other parts of the enamel organ form after the formation of the enamel is complete

Answer 44

a protective strucutre called the reduced enamel epithelium

Question 45

what do the dental papilla stem cells become

Answer 45

Odontoblasts, fibroblasts, reserve cells that eventually become the pulp of the tooth

Question 46

what does the dental follicle stem cells become

Answer 46

Cementoblasts, fibroblasts, osteoblasts, and reserve cells to become to periodontal ligament of the periodontium

Question 47

how is the enamel organ attached to both mesenchymal parts of the tooth germ

Answer 47

Basal lamina

Question 48

the space between the odontoblasts and the ameloblasts

Answer 48

the Future Dentinoenamel junction

Question 49

what is the roll of the reduced enamel epithelium

Answer 49

Protects the enamel from surrounding connective tissue until the tooth enters the oral cavity

Question 50

what is the cervical loop

Answer 50

The rim of the epithelial bell where the inner and outer epithelial layers meet

Question 51

the doubled epithelial layer of the enamel organ

Answer 51

Hertwig's epithelial rooth sheath

Question 52

Roll of hertwigs epithelial root shealth

Answer 52

Determines rooth dentin outline | Determines number of root canals of a tooth (NOT ROOTS)