DP06 Pathology of pulpitis

Question 1

What is pulpitis?

Answer 1

Inflammation of the dental pulp

Question 2

What are the 4 general aetiologies of pulpitis?

Answer 2

Microbial
Physical
Chemical
Iatrogenic

Question 3

How can microbes reach the pulp?

Answer 3

Dental caries
Attrition/abrasion
Cracked/fractured tooth
Invaginated odontome
Marginal leakage
Traumatic conservative procedures
Anachoresis

Question 4

How does caries allow pulpitis?

Answer 4

Inflammation starts before pioneer bacteria reach the pulp
Bacteria release soluble irritants which can move further than the bacteria

Question 5

When carious dentine is <1mm from the pulp what do you see?

Answer 5

Pulpitis

Question 6

How does bacteria enter through attrition/abrasion?

Answer 6

Destroys tooth tissue –> exposing dentine –> tubules –> pulp

Question 7

How does an invaginated odontome cause pulpitis?

Answer 7

Improperly matured enamel causes plaque in the invagination

Question 8

How do traumatic conservative procedures cause pulpitis?

Answer 8

Push carious tissue into pulp chamber

Question 9

How does anachoresis cause pulpitis?

Answer 9

Anachoresis is when bacteria reach the pulp via the vascular system

Question 10

What physical methods can cause pulpitis?

Answer 10

Thermal - (heat from drill, curing light, exothermic materials)
Electric/galvanic currents - (eg gold and amalgam near each other)
Barotrauma (divers in unpressurised aircrafts)

Question 11

What things can cause chemical irritation causing pulpitis?

Answer 11

Mostly irritation by restorative materials
Poor lining of cavities

Question 12

How does iatrogenic cause pulpitis?

Answer 12

Marginal leakage, traumatic procedures, heat in procedures, chemical irritants in filling materials etc

Question 13

What factors influence pulp inflammation?

Answer 13

Nature of irritant
Duration and severity of irritant
Local anatomy og pulp chamber
Pre-existing state of pulp
Host defences
Pulp chamber is rigid
Reduced sized apical vessels

Question 14

What does pressure rise due to oedema cause to the pulp?

Answer 14

Local collapse of venous microcirculation –> hypoxia –> anoxia –> localised necrosis –> chemical mediators –> more inflammation –> total necrosis

Question 15

How is pressure rise different in younger patients?

Answer 15

Wider apex, swelling might not completely collapse the vasculature

Question 16

What are the histological classifications of pulpitis?

Answer 16

Hyperaemia
Acute pulpitis
Chronic pulpitis

Question 17

What are the clinical classifications of pulpitis?

Answer 17

Reversible = Sharp pain, short duration, hot/cold/sweet, disappears when stimulus stops
Irreversible = Spontaneous, poorly localised throbbing pain, worse when lying down, wakes px at night

Question 18

What is the difference between open/closed pulpitis?

Answer 18

Open - communication with oral environment
Closed - no communication with oral environment

Question 19

What are the inflammation phases in the acute phase of pulpitis and what cells are involved?

Answer 19

Vasodilation –> hyperaemia –> heat/redness
Blood vessel permeability –> fluid/cell exudate –> oedema/pain
PMNs

Question 20

What are the inflammation phases in the chronic phase of pulpitis and what cells are involved?

Answer 20

Antigenic stimulation
Clonal expansion –> lymphoid hyperplasia –> lymphadenopathy
Fibrosis
Lymphocytes, plasma cells, macrophages

Question 21

Is inflammation of the lymph nodes seen in chronic pulpal inflammation?

Answer 21

No
Inflamed lymph nodes seen more in periapical inflammations

Question 22

What is the histology of healthy pulp?

Answer 22

Dentine
Predentine
OD layer
Weil’s basal zone (cell free zone)
Polymorphous zone (cell rich)
Central pulp

Question 23

What is the histology of the hyperaemic phase of pulpitis?

Answer 23

Dilation of blood vessles
Oedema
Some extravasation of erythrocytes
Diapedesis of leukocytes (PMNLs)

Question 24

What does diapedesis mean?

Answer 24

Migration of cells to surrounding tissue

Question 25

What is the histology of acute pulpitis?

Answer 25

Exacerbation of inflammatory process Continued vascular dilation Collection of PMNs increase Pulp abscess = pus + pyogenic membrane) Degeneration of OD layer

Question 26

What is the histology of chronic pulpitis?

Answer 26

Quiescence of a previous acute pulpitis or, Chronic from onset (weaker stimulus over longer time) Infiltration by lymphocytes and plasma cells Fibrosis Degeneration of OD layer

Question 27

What is the histology of chronic hyperplastic pulpitis?

Answer 27

Dark red polyp Wide open cavity Good apical blood supply Granulation tissue may become epithelialised - viable desquamated epithelial cells (free when biting hard foods etc) --> epithelium; possible also UMCs in pulp

Question 28

What is a polyp?

Answer 28

Hyperplastic granulation tissue

Question 29

What are pulp stones?

Answer 29

Calcified bodies with organic matrix Free, adherent, interstitial (surrounded by dentine)

Question 30

Difference between true and false pulp stones

Answer 30

True - tubules, predentine, odontoblasts False - concentric layers, no tubules

Question 31

What are dystrophic calcifications?

Answer 31

Scattered along collagen or aggregated

Question 32

What happens to the pulp with age?

Answer 32

Decreased volume, vascularity and cellularity Increased collagen fibre content

Question 33

What are the different ways causing pulpal necrosis?

Answer 33

Pulpitis Injury of blood supply Patients with sickle cell anaemia

Question 34

How can pulpitis cause pulp necrosis?

Answer 34

Breakdown of inflammatory cells --> liquefaction necrosis Pus formation --> abscess Additional infection by putrefactive bacteria --> gangrenous necrosis

Question 35

How does injury of a blood supply cause pulp necrosis?

Answer 35

Coagulative necrosis - coagulation of tissues inside

Question 36

How does sickle cell anaemia cause pulp necrosis?

Answer 36

Capillaries clogged by RBCs - coagulative necrosis

Question 37

What are the complications of pulpitis?

Answer 37

Periapical disease Osteomyelitis Cellulitis (face - cavernous sinus thrombosis, FoM ludwigs angina) Bacteraemia, septicaemia Brain abscess, convulsions, coma, death

Question 38

What forms of periapical disease can be caused by pulpitis?

Answer 38

Periapical abscess (acute or chronic) - continuous weak irritation causes apical pus formation Condensing osteitis - surrounding bone more compact Periapical granuloma - granulation tissue formation and bone resorption

Question 39

What can occur from a periapical granuloma?

Answer 39

Radicular cyst - from epithelial rests of Malassez in PDL Carcinoma arising in radicular cyst - rare but epithelium in cyst derived from epithelial rests may become malignant