Devlopment L9 - oral developmental biology Odontogenesis 3

Question 1

complete the journey

crown

IEE —-> ………………. —> …………………

Dental papilla —-> ………………. —> …………………

root

dental papilla —-> ………………. —> …………………

dental follicle —-> ………………. —> …………………

Answer 1

crown

IEE –> Ameloblasts –> Enamel

Dental papilla –> odontoblasts –> dentine

root

Dental papilla –> odontoblasts –> dentine

dental follicle –> Cementoblasts –> cementum

Question 2

root development is “driven” by what

Answer 2

hertwings epithelial root sheath

Question 3

dental follicle gives rise to cells of tooth support, what are these cells

Answer 3

cementoblasts - form cementum

fibroblasts - forms pdl collagen fibre

osteoblasts - forms bone alveolar

Question 4

are the roots formed before or after tooth eruption

Answer 4

after

Question 5

the outer and inner enamel epithelial cells are proliferating in response to signals from the mesenchyme.

this allows for the dental sac to be split in two sub areas, the papilla and follicle.

why has this split occured?

Answer 5

the cells that occupy the two sub areas react differently to the signals released from Hertwigs epithelial root sheath.

Question 6

describe what is happening in the image

Answer 6

HERS induces odontoblast formation

ondontoblast align themeselves with basal lamina

odontoblast go on to produce root dentine which differs from coronal dentine.

Question 7

HERS cells have secreted enamel matric proteins on the predentine surface, why?

Answer 7

enamel matrix proteins mineralise to form the hyaline layer

Question 8

after the formation of the hyaline layer what happens to the HERS cells

Answer 8

they disintergrate

Question 9

the disintegration of the HERS cells allow for the induction of which cells?

Answer 9

indiction of follicle cells, migrate to the root surface and form cementoblasts

Question 10

what is the function of cementoblasts

Answer 10

cementoblasts secrete cementum

Question 11

the cementum matrix mineralises, this allows the entrapment of which fibres?

Answer 11

PDL fibres

Question 12

what is the role of the hyaline layer

Answer 12

induces cementoblast formation

cements cementum to tooth

Question 13

there are two types of cementum, what are they?

Answer 13

acellular - primary

cellular - secondary

Question 14

the main cell type found in the periodontal ligament is?

Answer 14

spindle-shaped fibroblast are the main cell type.