Pathology of pulpitis

Question 1

When does acute inflammation happen and what happens?

Answer 1

It happens immediately in response to an insult/stimuli.

Dilation and increased permeability of microvasculature.
Exudation (oozing) of fluid
Emigration of leukocytes (particularly neutrophils)

Question 2

What are the potential outcomes of acute inflammation? (3)

Answer 2

Complete resolution occurs with regeneration of native cells and restoration to normalcy.

Healing by connective tissue replacement (fibrosis) occurs after substantial tissue destruction and in non-regenerating tissues.

Progresses to chronic inflammation

Question 3

What is chronic inflammation and what cells are involved?

Answer 3

Prolonged response to persistent stimuli

Involves lymphocytes, plasma cells and macrophages

Co-existing injury, inflammation and repair

Question 4

What is pulpitis?

Answer 4

Inflammation of the pulp

Question 5

What can lead to pulpitis? (3 ways)

Answer 5

Microbial
Thermal (e.g. insufficient cooling of handpiece)
Chemical

Question 6

How may bacteria gain access to the pulp? (5)

Answer 6

1. Carious cavitation
2. Attrition/abrasion/erosion
3. Fracture, cracked tooth
4. Perio-endo lesion
5. Iatrogenic (caused by the clinician)

Question 7

Name the 5 ways pulpitis can be classified

Answer 7

1. Acute or Chronic (clinical and histological)
2. Reversible or irreversible (clinical)
3. Open or closed
4. Subtotal or generalised
5. Sterile or infected

Question 8

Why is inflammation in the pulp chamber different to inflammation in other parts of the body? (2)

Answer 8

• Pulp chamber enclosed in dental hard tissue with limited blood supply through the narrow opening of mature apical foramen
• Increase in pulpal pressure due to oedema:
  Venous stasis > Ischemia > Necrosis

Question 9

What is usually the result of pulpitis?

Answer 9

• Pulpitis usually results in pulp necrosis with periapical periodontitis as an outcome

Question 10

What local factors affect healing in terms of pulpitis?

Answer 10

Blood supply
Degree of infection
Persistent irritation
Mobility

Question 11

What systemic factors influence healing in terms of pulpitis?

Answer 11

Age
Nutrition
Pre-existing medical conditions

Question 12

What HOST FACTORS influence the progress of pulpitis? (3)

Answer 12

Pulpal anatomy
Apical blood flow
Pre-existing state of pulp

Question 13

What IRRITANT FACTORS influence the progress of pulpitis? (3)

Answer 13

Nature
Severity
Duration

Question 14

Why is necrosis more common in pulp that other parts of the body?

Answer 14

Due to the local anatomy

Question 15

What happens in acute inflammation in the pulp? (8)

Answer 15

• Initial constriction THEN dilation of vessels
• Increased blood flow
• Formation of exudate
• Neutrophils
• Oedema
• Destruction of odontoblasts and adjacent pulpal tissue
• Variable necrosis
• Variable abscess formation

Question 16

What is in an abscess that may be formed in acute inflammation of the pulp?

Answer 16

Collection of exudate consisting of neutrophils, the liquefied debris of necrotic cells and oedema fluid

Question 17

What happens in chronic inflammation in the pulp?

Answer 17

Presence of lymphocytes, plasma cells, macrophages

Variable necrosis

Question 18

Why is it hard to diagnose which tooth may have pulpitis?

Answer 18

Because pulps of individual teeth are not precisely represented in the sensory cortex - so it is hard to localise and pain may refer.

Pain not provoked by pressure to tooth surface as infection/inflammation not spread to periapical tissues

Question 19

What may indicate that the patient is suffering from reversible pulpitis? (3)

Answer 19

1. Hypersensitive to hot AND cold
2. Pain subsides on removal of stimulus
3. Positive response to vitality testing

Question 20

What may indicate that the patient is suffering from irreversible pulpitis? (2)

Answer 20

Pain is persistent and spontaneous.

Reduced or no response to vitality testing.

Question 21

Describe the histology of reversible pulpitis (5)

Answer 21

1. Hyperaemia
2. Oedema
3. Chronic inflammatory cells underlying the area of affected dentinal tubules
4. scattered acute inflammatory cells are found occasionally
5. Can see reparative secondary dentine

Question 22

Describe the histology of irreversible pulpitis (3)

Answer 22

• often congestion of venules that results in focal necrosis
• Surrounding pulp tissue can show fibrosis
• Mixture of neutrophils, plasma cells, lymphocytes and macrophages

Question 23

What is the treatment for reversible pulpitis?

Answer 23

Removal of local irritant

Question 24

What is the treatment for irreversible pulpitis?

Answer 24

Tooth extraction or RCT

Question 25

Is the vast majority of pulpitis open or closed?

Answer 25

Closed

Question 26

What happens in open pulpitis?

Answer 26

Pulp survives chronically inflamed beneath a large exposure.

This is despite heavy infection.
Often associated with open apices giving a good blood supply (seen in children)

Question 27

What is chronic hyperplastic pulpitis (pulpal polyp)?

Answer 27

• Large carious exposures of the pulp in which entire dentinal roof often missing
• Chronic inflammation produces hyperplastic granulation tissue that extrudes from the pulp chamber - may or may not be covered with stratified squamous epithelium (that has migrated from adjacent gingiva)
  [granulation tissue can develop its own blood vessels]
• Apex may be open and reduces the chance of pulpal necrosis
  (tooth is asymptomatic except for a possible feeling of pressure when it is placed into masticatory function)

Question 28

In pulpal polyps, what may reduce the chance of pulpal necrosis?

Answer 28

If the apex is open

Question 29

Where are pulpal polyps most likely to develop?

Answer 29

In deciduous molars or first permanent molars in children

they have large pulpal chambers

Question 30

Outline some pulpal changes that may occur (3)

Answer 30

• Fatty change
• Fibrosis
• Calcified material (e.g. pulp stones, metaplastic ossification.)