Classification and histopathology of pulp disease

Question 1

What does enamel organ develop from?

Answer 1

Dental lamina

Question 2

Cells found in pulp

Answer 2

Fibroblasts and stem cells and some macrophages, lymphocytes (& lymphatics)

Question 3

Post-eruption dentine

Answer 3

Secondary and tertiary

Question 4

Secondary dentine

Answer 4

Physiological: laid down at relatively constant rate throughout life
Regular structure
Pulp gets smaller

Question 5

Tertiary dentine

Answer 5

Reactionary: laid down in response to insult to pulp
-structure varies
Reparative: occurs through differentiation of new odontblasts after odontoblasts have been killed
-poor structure

Question 6

Pulp stones

Answer 6

True: composed of dentine
False: amorphous calcifications
-increase in number and size with age

Question 7

Classification of pulp pathology

Answer 7

Inflammatory (pulpitis)
Degenerative
-fibrosis
-calcifications
-internal resorption
-may be age changes or 'idiopathic'

Question 8

Pulpitis

Answer 8

Most important disease to affect pulp
Inflammation of pulp
Most common aetiology: dental caries
Defence reactions of dentine (dentine sclerosis, reactionary dentine formation)

Question 9

Classification of pulpitis

Answer 9

Pulpitis –> acute or chronic
Acute –> open (i.e. pulp chamber open to oral cavity) or closed
Chronic –> open or closed
Acute open due to exposure, tooth fracture
Acute closed due to trauma
Chronic open due to open caries
Chronic closed due to caries

Question 10

Causes of pulpitis

Answer 10

Infection (bacterial)
Trauma
Secondary to attrition, abrasion, erosion

Question 11

Causes of pulpitis: infection (bacterial)

Answer 11

Dental caries (main cause)
Secondary to
-crack/ fracture
-lateral root canals
-canals in furcation
-invaginated odontome
Bacteraemia

Question 12

Causes of pulpitis: trauma

Answer 12

Physical
-direct blow
-heat
-dessication
Chemical
-filling materials/ liners
Mechanical
-cavity preparation

Question 13

Clinical features of pulpitis

Answer 13

Often poorly localised pain
May radiate to adjacent jaw, neck, face
Continuous or intermittent
Reversible, symptomatic irreversible or asymptomatic irreversible

Question 14

Correlation clinical and histological

Answer 14

Little to none

Question 15

Pulpitis

Answer 15

Occurs within closed environment i.e. limited by dentine
Little/ no collateral blood supply
Closed vs open apex (open better prognosis)

Question 16

Patterns of pulpitis

Answer 16

Starts as localised lesion directly related to proximity of caries e..g pulp horn
Inflammation will spread throughout pulp if caries untreated
Rate of progression and character of pulpitis will vary between teeth and individuals

Question 17

Protective responses

Answer 17

Tertiary dentine

• forms in response to caries
• > distance of pulp from irritant
• this reduces and may halt pulpitis

Question 18

Response to early dentine caries

Answer 18

Wheat sheaving indicated oedema in odontoblast layer
Tertiary (reactionary) dentine formation
> blood flow
Lymphocytes, plasma cells and macrophages
-At this stage it is possible pulpitis may resolve if caries removed or ceases to progress

Question 19

Response to late dentine caries

Answer 19

Acute inflammation
> vascularity
inflammatory exudate
accumulation of neutrophils
death of odontoblasts

Question 20

Natural history

Answer 20

Closed environment

• rapid rise in tissue pressure
• collapse of venous circulation
• leads to tissue hypoxia

Question 21

Natural history: pulp necrosis

Answer 21

Hypoxia leads to

• local tissue necrosis
• release of inflammatory mediators
• further inflammation and neutrophil accumulation
• formation of pus: pulp abscess

Question 22

Natural history: pulp abscess

Answer 22

May be:
localised to pulp horn
surrounded by granulation tissue

Question 23

Natural history: spread

Answer 23

Pulpitis may spread to involve whole pulp

• pus may drain into oral cavity if there is pulp exposure (‘open’ pulpitis)
• bacteria destroyed by neutrophils

Question 24

Following spread

Answer 24

Total necrosis may follow

One root may be affected first with spread of infection to apex in multi-rooted teeth

Question 25

What does untreated pulpitis lead to

Answer 25

Necrosis and periapical pathology

Question 26

Chronic hyperplastic pulpitis

Answer 26

‘pulp polyp’
Usually first permanent molars
-open apices - good blood suply
-open carious cavity with pulp exposure
Granulation tissue in pulp chamber
Surface ulcerated and covered by fibrin and neutrophils
May become covered by epithellium
-source of epithelium uncertain: either saliva or gingival crevice
Clinically appears red and bleeds easily (less so if epithelialsed), often painless

Question 27

Healing of pulp

Answer 27

Use of calcium hydroxide may stimulate dentine formation
Need contact with pulp for it to be effective
Clinically need to decide whether to ‘pulp cap’ or to extirpate pulp following exposure

Question 28

Pathological resorption

Answer 28

Internal
-secondary to pulpitis
-idiopathic (‘pink spot’)
External - many causes