1
Q
where does tooth pulp originate from
A
- ectoderm dental papilla (mesenchyme)
- commas of the mesenchyme tissue differentiate into fibroblasts and odontoblasts
- the fibroblasts form intercellular substance of the pulp
- the odontoblasts form the dentin
- blood vessels and nerves in dental papilla remain to supply pulp tissue
2
Q
where is dental pulp
A
- inside the tooth, surrounded by dentin
- occupies pulp chamber in crown
- occupies pulpal canals in root
- connects with PL at apical foramen
3
Q
is pulp mineralized? is it living
A
- no
- yes its living tissue
4
Q
what is pulp made up of
A
- cells
- intercellular substance: ground substance and collagen fibres
- tissue fluid
- also contains blood vessels, few lymph vessels for transporting WBCs, and some nerves
- also denticles
5
Q
what are the 2 types of nerves in the pulp
A
- sensory nerves -> transmit pain
2. motor nerves -> innervate smooth muscle cells in walls of blood vessels -> constriction and dilation
6
Q
what cells are found in the pulp
A
- fibroblast cells - star shaped
- histocyte cells/phagocytes (WBC)
- odontoblasts
7
Q
what are fibroblast cells
A
mesenchymal cells which become fibroblasts
- produce fibrous (meshwork of minute fibers) and ground substance (jelly like material) of intercellular substance
- most numerous type cell in young pulp
8
Q
what are histocytes
A
- start as undifferentiated mesenchymal cells
- located around capillaries
- part of pulp’s defence mechanism - respond to injury by changing into defence cells as seen in any inflammatory reaction
- phagocytes are the white blood cells that protect the body by ingesting harmful foreign particles, bacteria and tissue debris
9
Q
what are odontoblasts
A
- columnar cells
- next to dentin-pulp wall
- originated from cytoplasm in pulp and dentin
- produce dentin (primary, secondary, tertiary)
- pulpal wall changes position over time – formation of secondary dentin and narrowing of the pulp
10
Q
what are korff’s fibres
A
- thick collagenous fibers that begin in the dental papilla, spiral (corked rope) shape between the cells of the odontoblasts and help form the matrix of the dentin
11
Q
what do the blood vessels and lymphatic vessels in the pulp do
A
- supply o2 and nutrients and take away o2 and wastes
- branches from superior and inferior alveolar artery
- plentiful in young pulp
- enter via apical foramen
12
Q
what is the nerve supply from the pulp
A
- branches from the trigeminal nerve
- 2nd division of he trigeminal nerve - sensation mx
- 3rd division of the trigeminal nerve - sensation mn
- nerve endings located between odontoblasts cells bodies, some enter DT
13
Q
what are true pulp stones
A
- also called denticles
- formed during tooth development
- calcified bodies (mass of dentin) of irregular round shape and are found in the pulp
- may be free in soft tissue of the pulp or attached to dentin wall and become surrounded by secondary dentin
- vary in shape, size – increase in size with age
- problem with endo tx
- rarely a source of infection – no problems
14
Q
what are false pulpal stones
A
- diffuse calcifications
- small thin scatterings of calcified matrix
- found usually in root canals of older teeth
- clinically unimportant
15
Q
what are the 3 zones of the pulp that are evident when pulp tissues are viewed microscopically
A
- odontoblastic zone
- cell free zone
- cell rich zone
16
Q
what is the odontoblastic zone
A
- lines outer pulpal wall (closest dentin)
- formed by cell bodies of odontoblasts
- forms dentin (sclerotic dentin and reparative dentin)
- serves as first line of defence, forms secondary and tertiary dentin
17
Q
what is the cell free zone
A
- buffer area
- passageway
- allows movement and communication between 2 other zones
18
Q
what is the cell rich zone
A
- inner most layer
- cell reservoir
- undifferentiated cells; capable of differentiating into new odontoblasts (to form reparative dentin) and histocytes (defence cells)
- interstitial fluid between cells
- extensive blood supply and WBC for infection
19
Q
what are 5 major functions of the pulp
A
- formative
- sensory
- nutritive
- defensive
- vitality
20
Q
what is the formative function of the pulp
A
- odontoblasts for forming dentin
- korff’s fibers - fibrils in dentin - forming ground substance/matrix for dentin
- end - ceases function
21
Q
what is the sensory function of the pulp
A
- pulp sensitive to external stimuli
- nerve fibers in pulp -> sensation of pain
- hot, cold, touch are all interpreted as pain
- periodontal ligament is responsible for sensation of pressure
22
Q
what is the nutritive function of the pulp
A
- via bloodstream
- supplies itself (pulp) and odontoblast with nutrients
- provide nutrients to dentin through odontoblastic processes up to DEJ or DCJ
23
Q
what is the defence function of the pulp
A
- 3 types of reactions:
1. inflammatory reaction - if pulpal damage (histiocytes)
2. production of sclerotic dentin
3. production of reparative dentin
24
Q
what is the vitality of the pulp
A
- the pulp is what keeps the tooth alive
- after the tissue is removed, tooth becomes excessively brittle (fragile) and can break/fracture easily
- endodontic tooth - non-vital - perfectly fine but can become brittle over time
25
how does age change the pulp
- age does not alter function of the pulp
- changes happen to pulp as changes happen in different parts of the body -> normal changes, not pathological
- continues formation of secondary dentin - smaller pulp chamber and canals
- # cells decrease with age
- amount of fibrous intercellular substance increases as cells decrease
- blood and nerve supply decreases
- denticles - larger and more numerous
- increase in diffuse calcified false pulpal stones
26
what happens to a tooth without pulp
- can function for years without pulp, though enamel tends to become more brittle, can fracture easily
- pulp removed, less fluid - 'dries out'
- if no pulp - no formation of secondary or reparative dentin
Histology
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