Endodontics

Question 1

What is dental pulp?

Answer 1

Unique vital connective tissue within the root canal system.

Question 2

What are periapical tissues?

Answer 2

Vital tissues surrounding the root apex.

Question 3

How is the dental pulp connected to the periapical tissues?

Answer 3

Via the apical foramen, lateral/accessory canals, apical delta

Question 4

What are the primary functions of dental pulp?

Answer 4

1. Related to tooth formation

• Induction: including epithelial-mesenchymal interactions, induces differentiation of
  odontoblasts/ameloblasts
• Formation: odontoblasts form dentine and ameloblasts form enamel

Question 5

What are the secondary functions of dental pulp?

Answer 5

1. Related to support during tooth development and maintenance of health and vitality of the tooth
   - Nutritive
   - Sensory: proprioception, nerves respond to stimuli
   - Defence: protective and reparative, immune and inflammatory responses

Question 6

What are the components of dental pulp?

Answer 6

1. Cellular

2. Extracellular component

Question 7

What components make up the extracellular component?

Answer 7

1. Fibres
2. Ground substance
3. Blood vessels
4. Lymphatics
5. Nerves

Question 8

Organisation of the dental pulp

Answer 8

1. Odontoblast layer
2. Sub-odontoblast layer
3. Pulp proper

Question 9

Features of the odontoblast layer

Answer 9

• Sub-adjacent to dentine
• Contains odontoblastic cell bodies
• Morphology of odontoblasts reflects function
• Terminally differentiated cells
• New odontoblasts may differentiate from pluripotent cells from the sub-odontoblast layer

Question 10

Features of the sub-odontoblast layer

Answer 10

• Contains a cell free zone which is beneath the odontoblast later - contains processes of fibroblasts, blood vessels and nerves
• Also contains an underlying cell-rich zone which contains many undifferentiated cells, fibroblasts, immune cells, blood vessels and nerves

Question 11

Types of pulp proper

Answer 11

• Parietal and Central pulp

Question 12

Features of the parietal pulp

Answer 12

• Smaller blood vessels and nerve fibres

Question 13

Features of the central pulp

Answer 13

• Major blood vessels and verve fibres
• Fibroblasts
• Defence cells
• Collagen
• Dental Pulp Stem cells (DPSCs)

Question 14

Cells of the dental pulp

Answer 14

1. Odontoblasts
2. Fibroblasts - most numerous
3. Undifferentiated stem cells
4. Defence cells (macrophages, lymphocytes, pulp dendritic cells)

Question 15

Function of fibroblasts

Answer 15

Produce collagen and ground substance.

Also involved in collagen degeneration and turnover

Question 16

What are the age-related change of fibroblasts?

Answer 16

Young fibroblast: plump nucleus, stellate-shaped, prominent protein synthesis

Old: condensed nucleus, flattened

Question 17

Features of undifferentiated mesenchymal stem cells

Answer 17

1. Mainly found in the cell rich zone and throughout pulp
2. Pluripotent and primitive
3. Migrate and differentiate into odontoblasts in response to cell injury/death

Question 18

What is the most predominant immune cell of the pulp?

Question 19

What is the most predominant immune cell of the pulp?