Dentinogenesis

Question 1

dentinogenesis is a continuous process occuring throughout life and more dentine is deposited when there is an external stimulus, but what causes dentinogenesis to stop?

Answer 1

pulp removal/ tooth loss

NB. as more dentine is laid down throughout life, pulp size decreases

Question 2

dentine and enamel are hard tissues. where does their formation begin and in which direction does it continue

Answer 2

begins at cusp tips/ incisal edge

continues cervically

Question 3

when does dentinogenesis begin in the stages of tooth development

Answer 3

the late bell stage

Question 4

which cells differentiate to become odontoblasts

Answer 4

the OUTER cells of the dental papilla

Question 5

what triggers pre-odontoblast to differentiate into ondonotblasts

Answer 5

the ameleoblasts- they degrade the basal lamina which sends signals across the basement membrane

Question 6

what happens to the basement membrane once dentine if formed

Answer 6

it disappears

Question 7

what direction do odontoblasts move as they deposit dentine

Answer 7

odontoblast deposit dentine, and move DOWNWARDS towards core of dental papilla
ameoloblasts deposit enamel and move upwards towards the core of enamel organ

Question 8

what processes exist in odontoblast and what processes exist in ameleoblasts allowing them to create their respective matrixes

Answer 8

odontoblasts= have odontoblast processes. very long. 
ameleoblasts= have tomes processes

Question 9

describe the stages of dentinogensis

Answer 9

1. central cells of dental papilla in close contact with the basement membrane diffrentiate to become pre-odontoblasts
2. pre-odontoblasts diffrentiate to become odontoblasts
3. odontoblasts have bigger size, more golgi, more ER
4. the ameleoblast degrades the basal lamina, sends inductive signals to the odontoblast
5. the odontoblast nucleus moves to base of cell now, the odontoblast processes develop= lay down the dentine matrix
6. the 1st formed dentine/ the initial layer of mineralisaition is called mantle dentine

Question 10

how many odontoblast processes are in the odontoblast

Answer 10

initially, there are many, but the rest disappear and only one becomes dominant