Dentine formation + mineralisation

Question 1

When does dentine formation begin

Answer 1

Immediately before enamel formation

Question 2

What do odontoblasts lay down

Answer 2

Extracellular fibrillar matrix as they begin to move away from the future ADJ

Question 3

Where is the most recently formed layer of dentine always found

Answer 3

On the pulpal surface

Question 4

Where is the unmineralised zone of dentine

Answer 4

Immidiately next to the cell bodies of odontoblasts and is called predentine

Question 5

What is collagen primarily secreated by

Answer 5

• Secreated by the odontoblast cell body
• The odontoblast process secreates the other non-collagenous proteins

Question 6

What is mineralisation of the collagen matrix made easier by

Answer 6

The modification of the collagen matrix by various non-collagenous proteins, which gradually follows its secretion

Question 7

Where is mineralisation seen histologically

Answer 7

At the junction of the predentine and calcified dentine, which may display a linear/irregular interface

Question 8

What happens to the matrix during mineralisation

Answer 8

• Undergos considerable modification

Question 9

Whats the role of the odontoblast process in predentine

Answer 9

The secretion of matrix components

Question 10

Whats the role of the odontoblast process in mineralising dentine

Answer 10

To participate in the modification of the predentine matrix and its mineralisation

Question 11

How are the mineralisation of dentine and bone similar

Answer 11

Mineral crystals are added along a mineralisation front

Question 12

How are odontoblasts key to initiating and controlling mineralisation

Answer 12

Calcium transported by odontoblasts becomes a crystalline mineral in the dentine by deposition onto a template formed by Type 1 collagen fibrils

Question 13

What is likely to be mediated by Dentine Phosphoprotein (DPP)

Answer 13

Hydroxyapatite nucleation on collagen fibrils

Question 14

What 2 processes may be involved in the initiation of mineralisation in dentine

Answer 14

• Formation of the matrix vesicles in which mineral crystals develop
• Mineralisation by the combining of calcospherites found within pre-dentine. Discrete isolated islands of mineral become larger, denser and then fuse with advancing mineralisation front

Question 15

What may account for the irregular appearance of the mineralisiting front seen at some sites

Answer 15

Calcospherite formation and fusion

Question 16

Where is the pattern of calcospheric mineralisation not seen

Answer 16

In the alveolar bone