Dentine-Pulp Complex

Question 1

What is the common ancestry of the dentine and pulp tissue

Answer 1

The dental papilla

Question 2

Name the collagen types found in dentine and dental pulp

Answer 2

Dentine = type I collagen

Dental Pulp = type I, III and V collagen

Question 3

Why doesn’t peripheral dentin have any type IV collagen

Answer 3

As peripheral dentin has no basement membrane

Question 4

Describe the concept of the dentine pulp complex

Answer 4

The dentine pulp complex is a dynamic tissue that responds to mechanical, bacterial and chemical stimuli as a functional unit

Question 5

Describe the constituents and structure of dentine as a hard tissue

Answer 5

• High water content that can react to changes in environment
• Only tissue that is innervated
• Micrometer diameter tubules surrounded by highly mineralised peritubular dentin embedded within partially mineralised collagen matrix (interlobular dentine)

Question 6

When is primary dentin formed

Answer 6

Formed by odontoblasts during the development of the tooth

Question 7

When is secondary dentin formed

Answer 7

After tooth development the odontoblasts continue to deposit secondary dentine slowly throughout the life of the tooth

Question 8

When is tertiary dentine formed

Answer 8

Laid down rapidly on the pulpal aspect of areas of occlusal wear of disease

Question 9

What parts of the cells from the pulp are found within the dentinal tubules

Answer 9

• Odontoblastic processes
• Afferent nerve terminals
• Processes of some immunocompetent cells

Question 10

Where is dentinal fluid derived from

Answer 10

Pulpal extracellular fluid

Question 11

What blood vessels supply nutrients and dat to dentine

Answer 11

Pulpal blood vessels

Question 12

What happens to the properties of the dentine when the dental pulp dies or is removed

Answer 12

The dentine becomes an inert tissue incapable of any response or repair

Question 13

What may happen to the tooth when the pulp dies and the dentine exists in this non-vital state

Answer 13

• The tooth often becomes discoloured
• The tooth may fracture under masticatory forces but this structural weakness may be related more to the amount of tooth substance lost rather than to any intrinsic weakness of non-vital dentine

Question 14

What is the dentine-pulp complex’s reaction to traumatic stimuli

Answer 14

The reactions to the stimulus are aimed at reducing the permeability of dentine

Question 15

What dentin reaction is there to mild grades of injury like shallow carious lesions or mild tooth wear

Answer 15

Odontoblasts and other pulpal cells underlying the lesion may well survive and are stimulated or unregulated to secrete a reactionary type of tertiary dentine

Question 16

What happens when odontoblasts are displaced into the tubules

Answer 16

The internal cytoskeleton of dentine tubules is disrupted and causes cell death

Question 17

What can happen if dentine’s not sealed well following cavity preparation

Answer 17

This can cause microleakage within the restoration and can lead to acute pulpal reactions into the chonrnic stage due to micro-organisms and their products.

Question 18

What is phosphoric used for

Answer 18

Remineralisation in the ECM of the dentine

Question 19

When an injury that involves pulpal exposure that may kill the odontoblasts beneath the lesion what is the reaction of the dentine-pulp complex

Answer 19

The dead cells might be replaced by a new generation of odontoblast-like cells, secreting a reparative type of tertiary dentin, this requires recruitment of progenitor cell from cell rich layer in the pulpal tissue