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CSP3 YR5- Restorative > The Dentino-Pulpal Complex > Flashcards

The Dentino-Pulpal Complex Flashcards

1
Q

Dentine - basic overview?

A

Overview:

  • forms the bulk of the tooth
  • large number of parallel tubules in a generalised collagen matrix
  • tubules contain the processes of odontoblasts
  • sensitive
  • formed throughout life
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2
Q

Dentine - physical properties?

A

Physical properties:

  • fresh dentine is pale yellow
  • harder than the (_______) cementum
  • softer than the enamel
  • permeable, depending on the latency of the tubules
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3
Q

Dentine - chemical composition - inorganic and organic overview?

A
  • Dentine is 70% inorganic, 20% organic and 10% water
    Inorganic composition:
  • calcium hydroxyapatite; are Ca poor and carbonate rich
  • much smaller than enamel hydroxyapatite
  • found in and between collagen fibrils
    Organic composition:
  • Col I forms 90%
  • DPP and proteoglycans also present
    Hexagonal shaped crystals
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4
Q

Dentine - chemical composition - organic matrix? composition? Phospphoryn? Proteoglycans and role? Other present proteins? GF? Lilies?

A

Organic matrix:
- 90% of organic matrix (Col I)
- phosphophoryn (PP-H); main phosphoprotein (most acidic) and high calcium binding properties (implicated in mineralisation)
- main proteoglycans in dentine are bigkycan and decorin
- proteogly role in collagen assembly, cell adhesion, migration, differentiation and proliferation (role in mineralisation)
- GAGs also present
- y-carboxyglutamate-containing proteins in dentine
- bind strongly to hydroxyapatite crystals (role in mineralisation)
- acidic proteins; osteonectin, osteopontin present
- GF: IGF and TGF
Lipids:
- 2%
- phospholipids involved in formation and growth of apaptite crystals

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5
Q

Dentine tubules - location? Shape? Presentation? Xsec? Between tubules? Size changes and why? Secondary curvature? Branching?

A 
Location:
- extend from the pulp surface to the amelo-dentinal and the cementi-dentinal junctions 
Shape:
- curved sigmoid course 
Presentation:
- form primary curvature of dentine 
Xsec:
- circular
Between tubules:
- intertubular dentine
Size changes:
- 2.5um at pulpal end and 1um at enamel end
Why:
- odontobalsts retreat inwards, occupy a smaller area, and so the tubules become closer together 
Secondary curvatures:
- coincidenwith adjacent tubules gove risento contour lines of Owen
Branching:
- branch near the enamel-dentine junction
- in root, terminal branches loop
- more obvious in predentine
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6
Q

Dentine tubules - intratubular dentine - characteristics? Formation?

A

Formation:

  • walls of newly formed dentinal tubules at the pulp surface are made of Col I
  • maturation of tubules assoc with deposition of another type of dentine in walls
  • reduction in lumen (can be complete obliterated)
  • called intratubular dentine
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7
Q

Intratubular dentine - characteristics? Differences to inter?

A
  • lacks collagen matrix

- increased radiographic and electron density (15% more mineralised)

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8
Q

Intratubular dentine - inorganic component? physiological ageing?

A

Inorganic component:
- carbonated appetite with a different crystalline form
- hypocalcified areas
Physiological ageing:
- leads to complete obliteration of tubules with intratubular dentine (root dentine)
- appear translucent in water (butterfly Xsec, due to convergence of of tubules)

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9
Q

Contents of the dentinal tubules - odontoblastic processes - structure differences? Organelles? Location?

A

Structure differences:
- variable structure at various levels
Organelles:
- more in predentine area
- presence of microtubules and intermediate filaments
Location:
- inner layers of dentine, the processes occur the full width (remnants of processes seen in the peripheral parts of the tubules (after it has degenerated)
- degeneration of peripheral end (theory for withdrawal of odontoblasts

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10
Q

Contents of the dentinal tubules - afferent nerve terminals - location? Relationship? Organelles?

A 
Location:
- inner layers of dentine
Relationship:
- with the odontoblastic proces
Organelles:
- mito and vesicles
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11
Q

Contents of the dentinal tubules - sensory terminals - location? Size? Organelles?

A 
Location:
- coronal dentine beneath cusos (in 80% of tubules)
- sparse in cervical and root dentine
Size: 
- narrower than odontoblastic processes 
Organelles:
- microtubles and microfilaments
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12
Q

Contents of the dentinal tubules - antigen presenting cell processes - appearance? Role? Location?

A 
Apperance:
- small processes in the tubules near pulp
Role:
- immunocompetent APC
Location:
- within and beneath odontoblasts 
- processes limited to predentine
- extends deeper in tubules under caries
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13
Q

Contents of the dentinal tubules - extracellular dentinal fluid - brief composition? Role? Pa?

A

Composition:
- higher K and lower Na in comparison
Role:
- this balance affects the membrane properties of cells
Pa:
- positive force from the pulpal tissue pressure

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14
Q

Mantle dentine - formation order? Size? Differences from circumpulpal dentine?

A 
Order:
- most peripheral layer of dentine (1st)
Size:
- 20-150um
Differences:
- 5% less mineralised
- Col fibres perpendicular in the amelo-dentinal junction 
- branching of tubules 
- different mineralisation process
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15
Q

Interglobular dentine - shape? Fusion? Location?

A

Shape:
- minerals deposited as globular (calcospheres)
Fusion:
- form a uniform calcified tissue
Location:
- beneath mantle dentine (incomplete fusion)
- undercalcified interglobular areas appear dark
- tubules pass areas

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16
Q

Granular layer of Tome - what is it? direction? Role? Apperance?

A 
What is it:
- peripheral root dentine had a dark granular layer
Direction:
- dentinal tubules branch and loop back on themselves
Role:
- create air spaces
Apperance:
- tree top appreance of tubules
- hypimineralised granular layer
- incomplete fusion of calcospherites
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17
Q

Dentino-pulpal complex - Hyaline layer - located? Width? Structure basic? Helps with?

A 
Location:
- outaidenthe granular layer 
Width:
- 20um
Structure:
- atubular and structureless
Helps:
- in binding dentine to cementum
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18
Q

Dentino-pulpapl complex - Circumpulpal dentine - main? Structure basic?

A

Main:
- bulk of the dentine
Stricture:
- uniform except at peripheries

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19
Q

Dentino-pulpapl complex - predentine - when laid down? Structure during mineral? Width?

A 
Laid down:
- prior to mineralisation 
Structure during mineralisation:
- show a.globular or linear apperance 
Width:
- 10-40um
Thicker in younger teeth
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20
Q

Dentino-pulpapl complex - structural lines in dentine? Primary curvature? Secondary curvature? Incremental lines?

A 
Primary: curvatures of dentinal tubules;
- Schreger lines
Secondary: curvatures of dentinal tubules;
- contour of lines of Owen
Incremental lines:
- von Ebner's lines 
- Andresen lines
21
Q

Dentino-pulpapl complex - primary curvature lines (Schreger lines)? Section cut? Difficulty?

A

Section cut:
- longitudinally
Difficulty:
- to see in cross sections

22
Q

Dentino-pulpapl complex - secondary curvature lines (contour lines of Owen)? Location?

A

Location:

  • exaggerated line on the border of primary and secondary dentine
  • neonatal line
23
Q

Dentino-pulpapl complex - Von Ebner’s lines - location and size?

A

Von Ebner’s Lines:

  • cusp dentine: 4um separate every 2 lines
  • root dentine: 2um separate every 2 lines
24
Q

Dentino-pulpapl complex - Andresen Lines - size apart? lines found in-between?

A 
Size:
- 16-20um apart
Lines found inbetween:
- 6-10 lines of Owen between every 2 Andresen lines
Exaggerated neonatal line
25
Q

Dentino-pulpapl complex - physiological age changes? changes associated with dentinal responses to stimuli?

A 
Physiological changes:
- secondary and translucent dentine
Changes associated to dentinal responses to stimuli:
- tertiary and sclerotic dentine
- dead tracts of Fish
26
Q

Dentino-pulpapl complex -

Secondary dentine - start formation? similar structure? differences to primary?

A 
Start formation:
- form once the root is completed and the tooth comes into occlusion
Similar structure:
- to primary dentine
Differences:
- sudden change in tubule direction
- slower deposition thus less regular
- closer incremental lines
Close to pulp
27
Q

Dentino-pulpapl complex - Translucent dentine - how it occurs? location?

A

How it occurs:
- obliteration of tubules with intratubular dentine
Location:
- root dentine

28
Q

Dentino-pulpapl complex - Tertiary dentine - stimuli? types of dentine formed? variable appearance? differentiation? production of? interactions? Factors released (induces)

A 
Stimulus:
- external (trauma) induce the pulp to produce more calcified material
Dentine formed:
- irregular secondary dentine, reparative dentine, reactionary dentine, response dentine and osteodentin
Variable appearance:
- tubular, irregular and atubular
Differentiation:
- pulp cells into odontoblasts
- or original odontoblasts
Production of:
- Col I and dentine sialoprotein 
Interactions:
- epith-mesenchymal interactions
Factors released during inflammation?
29
Q

Dentino-pulpapl complex - Sclerotic dentine - stimuli? similar structure? different composition? composition? exposed tubules?

A 
Stimuli:
- induce the deposition of material inside the tubules (forming sclerotic dentine)
Similar structure:
- to transparent dentine
Diff composition:
- from intratubular dentine
Composition:
- apatite crystals and octacalcium phosphate crystals
Exposed tubules:
- might contain components from saliva
30
Q

Dentino-pulpapl complex - Dead Tracts of Fish - formed by? Sealed? defintion?

A

Formed by:
- primary odontoblasts killed (external stimuli)
- could retreat before form of intratubular dentine (forming empty tubules)
Sealed:
- at their pulpal end by tertiary dentine
- air filled, thus light will be internally reflected and they will appear dark
Definition:
- is the term given to these air filled tubules

31
Q

Dentino-pulpapl complex - Dentine sensitivity - different stimuli? food related stimuli? sensitivity due to? hydrodynamic theory? outward/inward movement stimuli?

A

Different stimuli:
- cold air/water
- mechanical contact (bur, probe)
- dehydration (cotton, air)
- heat produced during drilling
- chemicals
Food related:
- thermal changes
- osmotic changes
sensitivity due to:
- nerve endings in the dentine
- odontoblastic process
- movement of fluid within dentinal tubules
Hydrodynamic theory:
- stimuli applied to dentine cause fluid movement
- sufficient to depolarise nerve endings (in tubules, dentine-pulp junction and in plexus of Raschkow)
- stimuli cause outward movement of fluids (heat, osmotic pressure and drying)
- cold stimuli causes inward movement of fluids
- both movements affect nerve terminals
- tubular branching near DEJ explain higher sensitivity
- removing intracellular fluid disables a fibres

32
Q

Dentino-pulpapl complex - Dental pulp - general organisation (contained, continuous, what is it, composition basic), composition of pulp? Pulp fibres? Fibre formation?

A

General organisation:
- pulp contained within the pulp chambers and root canals
- apically, the pulp becomes continuous with the PDL
- specialised CT
- odontoblasts lie on peripheries, nerve terminals, APCs and BVs
- each root has one canal
- accessory canals apical third
Composition of pulp:
- cells in ECM
- 75% water and 25% organic
- fibres and non-fibrous matrix
- Col main component
Pulp fibres:
- Col I; fibrils thinly and randomly scattered, at the peripheries, parallel to predentine and right angles to the amelodentinal junction in mantle dentine (von Korff’s)
- Col III; in large amount, random scatter, only a1 chains and 41% pulpal collagen
- V and VI and fibrillin
Fibre formation:
- alpha chain (3)
- form procollagen (procollagen peptidase)
- collagen molecule
- assembles collagen fibril
- assembles fiber

33
Q

Dentino-pulpapl complex - pulp - nonfibrous matrix - GAGs (definition and types)? Proteoglycan (definition and types)? and adhesion molecules?

A

Non-fibrous matrix:
- GAGs; polysaccharide chain, bulku hydrophilic molecules from gel (chondroitin sulphate predominates also dermatan and heparan, also hyaluronan)
Proteoglycans: core protein surrounded by GAGs
- decorin (bind Col and TGFb)
- biglycan (reg Col fibrinogen)
- versican (proteogly aggreg)
- syndecan (attach to Col)
- Tensascin (cell adh)
Adhesion molecules: integrin
- fibronectin (cell attach to ECM, and cytoskel, reg cell shape, mig and diff)
- laminin (base mem and binds epith to ECM, bind sig mole, odontoblastic bodies and processes coated with laminin)

34
Q

Dentino-pulpal complex - Dental pulp - odontoblasts (description of cell, location, shapes in diff sections and cell junctions)

A

Odontoblasts:
- fully differentiated, polarised columnar cell with a long process inside a tubule
- cell body (50umx5-10um)
- small processes link adj odontoblasts and other pulp cells
- form a layer of single cells attached to the predentine (by single process)
- coronal odonto are columnar in outline, cuboidal in root
- oblique section (appear pseudostratified)
Cell junctions:
- desmosomes, tight junctions and gap junctions

35
Q

Dentino-pulpal complex - dental pulp - fibroblasts (location, production and degrad)

A

FIbroblasts:

  • scattered in pulp
  • slowly produce fibres and GS
  • pulp fibroblasts degrade ECM
  • matrix turnover
  • can produce hard tissue
  • prod of GFs and cytok
  • apoptosis
36
Q

Dentino-pulpal complex - dental pulp - immune cells - (T-lympho, macro and APC)

A 
T-lympho:
- small numbers increases during injury
Macrophages:
- diff morpho in rest form
- widely distributed and large numbers
- denser around BVs and odontoblast
APCs:
- 3 or more branching processes
- numerous around BVs and odonto
- induce lympho prolif and mig to lymph nodes
37
Q

Dentino-pulpal complex - dental pulp - undifferentiated cells (location and name?

A
  • beneath the odontoblastic layer capable of diff into odonto
  • pluripotent primitive mesenchymal cells could diff into cell variety
38
Q

Dentino-pulpal complex - dental pulp - BVs (relation, enter, course, branching, location, anastomoses, vasoconstrictor, blood flow)?

A

Relation:
- with nerves
Enter: arterioles and venules
- via the apical foramen and lateral canals
Course:
- run inside the root canals giving branches to the peripheries
Branching:
- within the coronal pulp chamber
Location:
- subodontoblastic capillary plexus (within and beneath odonto)
- base mem
Anastomoses:
- arterio-venous and venous-venous
Lymph vessels
Vasoconstrictor nerve endings in association with arteriole smooth muscle
Blood flow 2-60ml/min per 100g of tissue (high fluid Pa)

39
Q

Dentino-pulpal complex - dental pulp - nerve fibres (axons, myelination, fibre type, structure, enter)

A

Axons:
- 2500 enter a mature premolar
Myelination:
- 25% myelinated afferents
Fibres:
- 90% of which are Adelta fibres
- Adelta thin myelinated axons with a moderate conduction velocity (assoc with acute pain and temp Pa)
- remainder are Abeta fibres
- afferent fibres that carry non-noxious sensations
- unmyelinated C fibres majority (slow conduction, chronic or dull pain with sensations of warmth, mechanical and chemical)
Enter:
- as part of the neurovascular bundle
- branches end in and around odonto layer
- plexus beneath odonto (Raschkow)

40
Q

Dentino-pulpal complex - dental pulp - nerve fibres (branches, facilitates, vasodil)

A 
Branches:
- enter dentinal tubules
- many axons in tubules, at peripheries of dentine and among odonto bodies are devoid of schwann
- facilitates response to stimuli
Vasodilator:
- CGRP is potent vasodilator
- control pulpal blood flow
- synth by neurons and transported by axons
- control hard tissue form
- nerve in pulp maintain local environ
41
Q

Dentino-pulpal complex - dental pulp - regions?

A

Regions:

  • supraodonto region
  • odonto layer
  • subodontoblastic (cell free zone of Weil and cell rich zone)
  • Bulk of pulp
42
Q

Dentino-pulpal complex - dental pulp - supraodonto region (location, appear due, axons, tubules)

A

Location:
- between odontoblastic cell bodies and the predentine
Appear due:
- to tissue shrinkage
Axons:
- unsheathed axons are present (predentinal plexus of Bradlaw)
Tubules:
- where changes in tubules can be detected

43
Q

Dentino-pulpal complex - dental pulp - Cell free zone of Weil (processes, location)

A

Processes:

  • fibroblasts, odonto, axons and capillaries
  • anuclear zone
  • only in coronal pulp of erupted teeth
44
Q

Dentino-pulpal complex - dental pulp - cell rich zone (plexus, cell associated)

A 
Plexuses:
- subodontoblastic capillary plexus
- subodontoblastic neural plexus
Cell associated:
- with these plexi could result in the richness of this zone
45
Q

Dentino-pulpal complex - dental pulp - bulk of pulp (description)

A

Description:

  • central area of pulp
  • loose CT
  • rich blood and nerve supply
46
Q

Dentino-pulpal complex - dental pulp - ageing of pulp? (what occurs, calcification)

A 
Ageing of pulp:
- pulpal size decreases
- decreased vascularity
- more fibrous
- reduced innervation
Calcification:
- pulp stones
47
Q

Dentino-pulpal complex - dental pulp - pulp stones (#, denticles, attached, complications)?

A

Pulp stones:

  • single or groups
  • true denticles resemble dentine (tubular)
  • false denticles resemble bone (trapped cells)
  • stones attached to dentine
  • complication of root canal therapy
48
Q

Dentino-pulpal complex - dental pulp - clinical considerations?

A

Clinical considerations:

  • defects mediate through pulp
  • pulp inflamm (pain and difficult to localise)
  • exposure of lateral canals to the oral environ
  • exposure to cavity prep
  • root canal treatment
  • transformation into granulation tissue following trauma, leading to resorption to dentine by odonto
  • internal resorp of pulp
  • pinkish colouration of tooth

CSP3 YR5- Restorative (44 decks)

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