tooth development 2:)

Question 1

tooth stages

Answer 1

initiation
morphodifferentiation
cytodifferentiation

Question 2

what is cytodiffernetiation

Answer 2

differentiation of cells to produce specialised dental tissues

Question 3

what happens during cytodifferentiation after growth of correct shaped tooth germ

Answer 3

IDE differentiated into ameloblasts

dental papilla differentiates into odontological blasts

Question 4

how does the IDE differentiate into ameloblasts

Answer 4

sequentially from the tip moving down towards IDE

Question 5

what do ameloblasts and odontoblasts produce

Answer 5

enamel

odontoblasts

Question 6

where is predestine found

Answer 6

adjacent to odontoblast cells

Question 7

what is the junction between enamel and dentine tissue

Answer 7

amelodentinal junction

Question 8

steps of cytodifferentiation

Answer 8

IDE undergoes selective mitosis in the morphodifferentaition stage - ID induces dental papilla to form odontoblasts
odontoblasts secrete dentine and induce the IDE to differentiate into ameloblasts (upper parts first)
ameloblasts move outwards in the enamel organ to produce enamel tissue
dentine forms via an inwards direction
dental papilla reminas in the middle to form the pulp

Question 9

where does cytodifferentaiotn occur first in incisors and molrs

Answer 9

incisor
- underneath what becomes incised edge
molars
- underneath what becomes cusp tips

Question 10

root formation stages

Answer 10

induction
morphodifferentaion
cytodifferentation
- required to give number, shape length and dentine/dementum structure

Question 11

when does root formation stard

Answer 11

as crown formation is completing

Question 12

what is the situation once crown has almost completed

Answer 12

EO is reduced in size

two layers of EO are continuous at the cervical loop (where the cervix of the tooth is)

Question 13

what happens to the two layer of the EO once it is reduced in size

Answer 13

two layers combine to form the epithelial root sheath

• grow down between the dental papilla and dental follicle
• maps out the shape and length of roots

Question 14

what does each root sheath form and for multi rooted teeth

Answer 14

form a cylinder around the dental papilla
MRT
- root sheath separated into 2/3 individual root sheaths

Question 15

where does the root start to divide

Answer 15

furcation

Question 16

what does the root sheath induce

Answer 16

differentiation of odontoblasts from dental papilla

- cell division occurs at the growing tip to continue elongation of root sheath until root length is established

Question 17

what happens to the root sheath during cell divison

Answer 17

root sheath extends and stretches into a network of cells
allows dental follicle to contact dentine through gaps between the cells
islets of cells are epithelial cell rests

Question 18

what is dentine and dentine follicle derived from

Answer 18

ecotomesenchyme

Question 19

what does the root sheath secrete and why

Answer 19

hyaline layer

- provides inductive effect on the dental follicle lying outside

Question 20

what does the hyaline layer do

Answer 20

induces dental papilla to differentiate into

1) cementomalsts to form cementum
2) fibroblasts to form collagenous bundles of PDL