Regeneration of dentine/pulp-like tissue using a dental pulp stem ...
Dental Pulp
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Transcript of Dental Pulp
DENTAL PULP
Dr. Blagoja Lazovski
dr. Blagoja Lazovski 1
INTROUDCTION
dr. Blagoja Lazovski
The Pulp is a soft mesenchymal connective tissue that
occupies pulp cavity in the central part of the teeth.
It is a special organ because of the unique
environment
2
DEVELOPMENT
dr. Blagoja Lazovski
During the 8th week of IUL, there is condensation of the mesenchmye under the enamel organ-Dental papilla.
The enamel organ enlarge and enclose the dental papilla in their central portion.
Dental papilla controls the morphology & type of tooth to be formed.
Dental papilla shows :
extensive proliferation of cells
High vascularity
3
dr. Blagoja Lazovski
Following the differentiation of the IEE into
ameloblasts, odontoblast differentiate from the
peripheral cells of dental papilla
Well organized capillaries are found at
beginning of dentinogenesis
4
dr. Blagoja Lazovski
Capillaries crowd around the odontoblast during
active dentinogenesis
Rim of the enamel organ (IEE & OEE) is the cervical
loop.
Root formation is carried out by the proliferation of
cells at the cervical loop.
5
Dental Papilla
Dental papilla capped by the
enamel organ
dr. Blagoja Lazovski
6
GENERAL FEATURES
dr. Blagoja Lazovski
Total of 52 pulp organs 32 in the permanent and
20 in the primary teeth.
Total pulp volume in permanent teeth is 0.38cc with
mean being 0.02CC
Each of these organs has a shape that conforms to
that of the respective tooth.
Has ability to form dentin throughout life
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dr. Blagoja Lazovski
The pulp cavity is divided into
1. Coronal pulp
2. Radicular pulp
8
CORONAL PULP
dr. Blagoja Lazovski
It is the pulp occupying the pulp chamber of the crown of the tooth
In young teeth it resembles the shape of the outer dentin
It has six surfaces : occlusal, mesial, distal, buccal, lingual and floor.
Pulp horns are projections into the cusp
This pulp constricts at the cervical region where it continues as the radicular pulp
9
RADICULAR PULP
dr. Blagoja Lazovski
It is the pulp occupying the pulp canals of the root of
the tooth
In the anterior tooth it is single and in the posterior
teeth it is multiple
The radicular portions of the pulp is continuous with
the periapical tissues through apical foramen
As age advances the width of the radicular pulp is
reduced, and so is the apical foramen.
10
APICAL FORAMEN
dr. Blagoja Lazovski
1. Pulp cavity terminates at root apex as small opening called apical foramen
2. Radicular pulp continuous with connective tissue of the periodontium through this foramen.
3. Diameter in an adult- maxillary teeth-0.4mm
mandibular teeth-0.3mm
4. Wide open during development of root
11
APICAL FORAMEN
dr. Blagoja Lazovski
5. Undergoes changes
I. Tooth may tipped from horizontal pressure cause apex to tilt in opposite direction, exert pressure on one wall of the foramen causing resorption
6. Same time cementum laid down on opposite side resulting relocation of the original foramen
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dr. Blagoja Lazovski
7. Sometimes apical opening is found on the lateral
side of the apex
8. There may be 2-3 foramina split by cementum or
dentin- APICAL DELTA
13
Apical Foramen
Neurovascular bundle entering pulp through the foramen
dr. Blagoja Lazovski
14
ACCESSORY CANAL
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Leading laterally from the radicular pulp into the
periodontal tissue.
Present in the apical third of the root sheath cells
Formed due to premature loss of HERS or when
developing root encounters a blood vessel.
Overall occurrence is 33%
May also be present at the furcation region
15
Accessory Canals
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16
Structural Organization of pulp
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17
HISTOLOGICAL ZONES OF PULP
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ODONTOBLAST LAYER
CELL-POOR ZONE
CELL-RICH ZONE
PULP PROPER
18
THE ODONTOBLASTIC ZONE
dr. Blagoja Lazovski
A layer of odontoblasts are found along
the pulp periphery.
They are dentin forming cells.
19
dr. Blagoja Lazovski
CELL FREE ZONE
It is also called weil’s zone
40 microns wide &relatively free of cells
Traversed by
1. blood vessels
2. unmyelinated nerves
3. cytoplasmic process of fibroblasts
This zone is found below the odontoblastic zone
Represents the space into which odontoblasts move during tooth development.
20
CELL RICH ZONE
dr. Blagoja Lazovski
Present in subodontoblastic layer
Contains more proportions of fibroblast and undifferentiated mesenchymol cells.
Also contains macrophages, dendritic cells and lymophocytes.
Zone formed due to migration of cells from pulp proper
Mitosis seen when dead odontoblasts are replaced
Also contain young collagen fibres during early dentiogenis.
21
PULP CORE
dr. Blagoja Lazovski
It is central region of the pulp
Contains major blood vessels and nerve of the
pulp
Pulpal cells and fibroblasts are also seen
22
CELLS OF PULP
dr. Blagoja Lazovski
ODONTOBLASTS
FIBROBLASTS
UNDIFFERENTIATED CELLS
DEFENSE CELLS
23
ODONTOBLASTS
dr. Blagoja Lazovski
A Peripheral area of the pulp where the odontoblasts reside is termed odontogenic zone.
Arranged in Palisading pattern cells one tall columnar forming a layer of 3 to 5 cells in depth.
Shape may vary cornal pulp- columnar
midportion - cuboidal
Apical region - Flattened
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dr. Blagoja Lazovski
These cells have large process extending into
dentin
The no of odontoblasts corresponds to the
number of dentinal tubules
Average no of odontoblasts estimated to 45,000
per Sq.mm of odontogenic zone.
Odontoblasts in the crown are larger than in the
root.
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Shape of the odontoblasts also reflect the
functional activity of the cell.
During active phase, cells show increase in
endoplasmic reticulum golgi appartus and
secretory vesicles.
Resting (or) Non active phase cells are flattened
little cytoplasm condensed chromatin and
decrease no of ER
26
JUNCTIONAL COMPLEX
dr. Blagoja Lazovski
Numerous junctions such as gap junctions tight junction and desmosomes are found between odontoblasts.
Indicating exchange of ions and small molecules.
They promote cell to cell adhension and play a role in maintaining polarity of odontoblasts
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JUNCTIONAL COMPLEXES 28
ODONTOGENIC PROCESS
dr. Blagoja Lazovski
Odontoblasts give off a single process that extends into dentin and housed within dentinal tubules
These process devoid of major organelles
They contain abundance of microtubular filaments and coated vesicles
Mainly composed of protein-tubulin, act in and vimentin
29
FUNCTIONS OF ODONTOBLASTS
dr. Blagoja Lazovski
Synthesis of organic matrix
Synthesis of non collagenous substances like
sialoprotein, phosphophoryn, osteocalcin,
ostenoectin & osteopontin
Intracellular accumulation of calcium
Degradation of organic matrix
30
FIBROBALSTS
dr. Blagoja Lazovski
Cells that occur in greatest number in the pulp
Function is to form, maintain the matrix that consists
of collages, fiber and ground substance throughout
the pulp
The fibroblasts are stellate shaped cells having
extensive process.
31
Fibroblast
H&Estain
Immunohistochemical
method
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32
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Young teeth - Fibroblasts have abudant
cytoplasm having numerous cell organcells.
Older pulp - Fibroblasts appear spindle shaped
posses short processes having few cytoplasmic
organelles such cells are called fibrocytes
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dr. Blagoja Lazovski
Dual function :
a) It has capability of ingesting and
degrading the organic matrix.
b) Pathway of both synthesis and degreadation
in the same cell.
34
UNDIFFERENTIATED MESENCHYME
dr. Blagoja Lazovski
These mesenchymal cells are distributed through out the pulp, frequently around the perivascular area - believed to be toti potent cell
They are Polyhedral shaped with peripheral processes and large oval nuclei
Difficult to differentiate from fibroblast under light microscopy
Under adequate stimilus they may differentiate into odontoblast or fibroblast or macrophages.
In older pulp,their number and ability to differentiate comes down
35
IMMUNOCOMPETENT CELLS
dr. Blagoja Lazovski
They play a major role local inflammation and immunity.
They are recruited from blood stream and remain as transient inhabitants in pulp
These cells are
1. Macrophages
2. Mast cells
3. Plasma cells
4. Lympocytes,Neutrophils,Eosinophils basophils and manocytes.
36
MACROPHAGES IN PULP
dr. Blagoja Lazovski
Described as histiocytes (or) as resting wandering cells
Located close to blood vessel
Have several phenotypes
Macrophages are phagocytes,function of which are engulfment and digestion of foreign material
During inflammation they appear in large no to aid in defense the organism
In all they constitute 8-9% of the pulpal cell population
37
Macrophages
Dark staining nucleus with cytoplasmic
granules
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38
PLASMA CELLS
dr. Blagoja Lazovski
Plasma cells are seen during inflammation of the
pulp
The plasma cells function in the production of
antibodies.
Plasma cells may be present in coronal pulp
They have small nuclei with radiating chromatin
that appears like a cast wheel.
39
Plasma Cell
Peripheral arrangement of chromatin in
nucleus
dr. Blagoja Lazovski
40
MAST CELLS
dr. Blagoja Lazovski
Occur in small groups in relation to blood vessels
Present only during pulpal inflammation
Have round nucleus and contain many dark staining
granules in the cytoplasm.
Their number increase during inflammation.
41
LYMPHOCYTES,EOSINOPHILS AND
LEUCOCYTES
dr. Blagoja Lazovski
Usually found extravascularly in the normal pulp
During inflammation they increase in number.
Lymphocyte present along the walls of blood vessels
Involved in initial immunodefense
Usually they are not found in uninflamed pulp
42
dr. Blagoja Lazovski
Eosinophils are present in some allergic types of
inflammation
In pulp.they are found in an inflammatory exudate.
43
LYMPHOCYTES IN PULP
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Leucocytes are not found normally in the
connective tissue
They are transported to such sites in response to
injury and then present directly in the involved
tissue as well as in blood.
They phagocyte foreign material .
45
EXTRACELLULAR MATRIX
dr. Blagoja Lazovski
Connective tissue fibers
Collagen
Elastin
Fibronectin
Ground substance
Proteoglycans
Glycosaminoglycans
Basement membrane
46
FIBRES (COLLAGEN FIBRES)
dr. Blagoja Lazovski
Extra cellular structural protein,major constituent of
connective tissue
Collagen fibers appear throughout the pulp
young fine fibers ranging in diameter from 10-12mm.
Pulp collagen fibers do not contribute to dentin matrix
production.
47
dr. Blagoja Lazovski
After root completion pulp matures and bundles of
collagen fibers increase in number
They scattered throughout the coronal or radicular
pulp,or they appear in bundles.These are termed
diffuse or bundle collagen
Most prevalent in root canals,especially near
apical region.
48
Collagen Fiber
Seen in relation with fibroblasts
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dr. Blagoja Lazovski
Type I:
Present as thick striated fibrils
Responsible for pulp architecture
Type III:
Thinner fibrils,mainly distributed in
cell free and cell rich zones
Contributes to the elasticity of pulp
50
dr. Blagoja Lazovski
Type IV:
Present along the basement membrane of blood
vessels
Type V and VI:
Seen to form dense meshwork of thin microfibrils
through out the stroma
51
dr. Blagoja Lazovski
Collagen turnover is maintained by fibroblasts
During bacterial infection &
inflammation,collagenolytic activity is
accelerated following collagenase produced by
bacteria,PMN & fibroblats
Collagen synthesis is accelerated during
reparative dentin formation
52
ELASTIC FIBER
dr. Blagoja Lazovski
1. This has the ability to expand and contract
like a rubber band
2. Elastic fibers are first formed in bundles of
thin micro filaments called Oxytalan fibers
3. Elastin is then deposited in between oxytalan
fibers.
4. Always associated with larger blood vessels
53
Elastic Fiber
Verhoeff's method stains the fibers black
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54
FIBRONECTIN
dr. Blagoja Lazovski
It plays a role in cell-cell & cell-matrix adhesion
Has a major effect on the proliferation, differentiation & organization of cells.
Seen around the blood vessels
Also found in odontoblast layer with fibers passing into predentin
55
dr. Blagoja Lazovski
Due to its close interaction with odontoblasts and
extracellular fibers,fibrinoectin helps to maintain cell
morphology and provide a tight seal at this site.
Fibronectin may be involved in cell migration and
anchorage in the wound healing process of the
connective tissue of pulp.
It regulates the migration and differentiation of
secondary odontoblasts
Adherent property of fibronectin is due to cell surface
glycoprotein receptors called Integrins
56
GROUND SUBSTANCE
dr. Blagoja Lazovski
It is a structureless mass,makes up the bulk of the
pulp
Consists of complexes of proteins,carbohydrate
and water.
Broadly classified as
Glycoaminoglycans
Proteoglycans
57
GLYCOSAMINOGLYCANS
dr. Blagoja Lazovski
GAG found in pulp is mainly chondroitin
sulphate,dermatan sulphate & hyaluronic acid
Proteoglycans occupy larger area and they provide
protection against compression.
During dentinogenesis,the ground substance show
affinity for collagen and influence fibrinogenesis
They have capacity to bind with calcium and help in
mineralisation
58
BASEMENT MEMBRANE
dr. Blagoja Lazovski
It is a sheet like arrangement of extra cellular
protein matrix at the epithelial-mesenchymal
interface
Composed of 2 layers
lamina densa-electron dense
lamina lucida-electrolucent
59
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Basement membrane is a product of connective
tissue and epithelium
It is composed of
Collagen type IV
Laminin-adhesive glycoprotein
Fibronectin
Heparin sulfate
60
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Collagen IV provides binding sites for the rest of
basement membrane components
Laminin binds to both cells of connective tissue
and epithelium
In mature pulp,basement membrane forms
interface along endothelial cells & schwann cells
61
FUNCTIONS
dr. Blagoja Lazovski
Act as sieve between epithelium and connective
tissue
Helps in organisation and differentiation by
enabling interactions between extra cellular
molecules and cell surface receptors
Eg: Odontoblasts during tooth
development
62
CIRCULATION OF THE PULP
dr. Blagoja Lazovski
The pulp organ is extensively vascularized.
They are supplied by the superior and the
inferior alveolar arteries
The blood vessels gain entry into the pulp through
the apical foramen and at times through
accessory foramen.
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dr. Blagoja Lazovski
The arterioles on entering the pulp show a
reduction in thickness of vessel wall musculature
and therefore luman size increases.
Pulpal blood flow is more rapid than in most area
of the body
So pulpal pressure is highest of body tissues
The flow of blood in asterioles - 0.3 to 1mm/sec
Venules – 0.15mm/sec
Capilaries – 0.08mm/sec
64
Organization of Pulp Vasculature
dr. Blagoja Lazovski
⃟ Pulp is a micro circulatory system which lacks true arteries and veins
⃟ The largest vessels are arterioles & venules which regulate the local interstitial environment
⃟ They enter the tooth through the apical foramen
⃟ Pulp tissue pressure is 14cm H20
65
Organization of pulp vasculature
neurovascular bundle
dr. Blagoja Lazovski
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dr. Blagoja Lazovski
ARTERIOLES:
Arterioles
(50µ diameter)
Terminal arterioles
Precapillaries
Metarterioles
Capillaries (8µ)
67
dr. Blagoja Lazovski
The branching point of terminal arterioles is
characterized by smooth muscle clumps that act
as sphincters which are under the local cellular &
neuronal control
Thus pulpal inflammation elicits a localised
circulatory response restricted to the area of
inflammation
Arteriolar pressure – 43mm Hg.
68
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Apical third Middle third
PULP VASCULATURE
69
Microcirculatory System
Arterioles & venules
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70
CAPILLARIES
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Function as exchange vessels regulating the transport of diffusion of substances between blood and local interstitial tissue elements
They consists of single layer of endothelium surrounded by basement membrance
Capillary pressure –35 mmHg
Capillary wall is 0.5µ thick & acts as semipermeable membrane
71
dr. Blagoja Lazovski
Based on the property of semi permeability
capillaries may be grouped as
Class I : Fenestrated capillaries
Class II: Continuous capillaries
(non fenestrated)
Class III : Discontinuous capillaries
Class IV : Tight junction capillaries
Class I & II are present in the dental pulp
72
Capillary network is organized in 3 layers
dr. Blagoja Lazovski
1. Terminal capillary network located in the “odontoblastic layer”
2. “Capillary network” present adjacent to the odontoblastic layer & consists of pre capillary & post capillary vessels
3. Venular network of vessels
During aging & decreased metabolism these layers appear as single layer
73
SEM shows extensive arborization of capillaries from the
metarterioles
dr. Blagoja Lazovski
74
VENULES
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Collecting venules receive pulpal blood flow from
the capillaries & transfer it to the venules
Arterio-venous anastomosis permits direct
shunting from arterioles to venules
Venular pressure –19mm Hg
75
LYMPHATICS
dr. Blagoja Lazovski
Lymphatic vessels are formed from fine meshwork
of small, thin walled lymph capillaries
Lymph capillaries coalesce to form larger
lymphatic vessels with valves
They start as blind openings near Weil’s zone &
odontoblastic layer
The larger lymphatic vessels run along the blood
vessels & nerves
76
dr. Blagoja Lazovski
Multiple collecting lymph vessels exit though the apical foramen & drain lymph from pulp into the periodontium
Role in pulp:
They remove high molecular solutes from the interstital fluids thus maintain interstitial COP
They transport lymph to the regional lymph node before it enters into the blood vessels. This provides an immuno surveillance function.
77
METABOLSIM
dr. Blagoja Lazovski
Metabolism has been studied by measuring the rate of O2 consumption & production of Coz lactic acid by pulp tissue
Radiospriometry is also used to evaluate the metabolism. Pulp tissue is placed in 14C labeled substractures, such as succinate & rate of apperance of CO2 is measured.
During dentinogenesis, rate of O2 consumption is high than after crown completion.
78
dr. Blagoja Lazovski
Greatest metabolic activity is seen in the
odontoblast layer.
Reduced pH of pulp causes decreases in O2
consumption as in pulp abscess.
In addition to the glycolytic pathway, the pulp
has the ability to produce energy through
Pentose shunt pathway, suggesting that the pulp
can function under varying degrees of ischemia
79
dr. Blagoja Lazovski
Several dental materials have shown to inhibit O2
consumption Eg. ZOE , Ca(OH)2 & silver amalgam
Pulpal irritation causes increases in
cycloxygenase products, which is inhibited by
ZOE
As cellular composition reduces, the rate of
oxygen consumption decreases.
80
INNERVATION
dr. Blagoja Lazovski
Principles role is to help in conscious recognition
of irritants to the pulp, which gives the
opportunity to have the problem corrected
before irreversible effects can occur
Nerve fibers, mylinated & unmyelinated, enter
the tooth through the apical foramen
81
INNERVATION
dr. Blagoja Lazovski
Dental pulp contains sensory and motor fibers to
fulfill the vasomotor and defense function
Sensory afferent fibers are branches of
maxillary & mandibular division of trigeminal
nerve.
82
dr. Blagoja Lazovski
After entering the foramen, they arborize. Larger
fibers are present in the central zone. They
divide as they proceed peripherally and
coronally.
Subjacent to the cell rich zone, the nerves branch
extensively forming a parietal layer of nerves-
NERVE PLEXUS OF RASHKOW. This layer
contains both A and C fibers.
83
Types of nerve fibers
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84
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Above the cell free zone, myelinated fibers begin
to lose their myelin sheath.
In the cell free zone, they form a rich network
responsible for pain
In the cell free zone, they form a rich network
responsbile for pain.
Many of these fibers pass between the
odontoblastic zone.
85
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Nerve endings may also enter the dentinal
tubules
incidence - 10-20% in cusp tips
1% at the level of CEJ
Motor nerves are supplied by the sympathetic
division of autonomic nervous system.
86
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They wrap around the arteries and terminate in
the tunica media.
They control the diameter of the vascular lumen &
therefore blood flow & volume & ultimately the
intrapulpal pressure.
87
Table 3.2 Classification and function of fibers in peripheral nerves
Fiber
Diameter
(m)
Conduction velocity
(speed of impulse,
m/sec)
Function
A-alpha ()
A-beta()
6-20
5-12
15-80 (myelinated)
30-70
Afferent fibers for touch, pressure
proprioception, vibration
(mechanorecptors)
A-gamma()
A-delta ()
B
1-5
1-3
2-30 (myelinated)
3-15 (myelinated)
Afferent fibers for pain and temperature
Visceral afferent fibers preganglionic
visceral efferent fibres
C 04-1.0 0.4-2(unmyelinated) Afferent fibers for pain and tempature;
post ganglionic visceral efferent fibers
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Neuropeptides in Pulp
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Neuropeptides are proteins that have been associated with central & peripheral nervous system
Following are the neuropeptides demonstrated in pulp :
Originate from trigeminal ganglion (C fibres)
Substance P
CGRP
Neurokinin A
89
FUNCTIONS OF DENTAL PULP
dr. Blagoja Lazovski
INDUCTIVE
FORMATIVE
NUTRITIVE
PROTECTIVE
DEFENSE
90
INDUCTIVE
dr. Blagoja Lazovski
It induces oral epithelial differentiation into
dental lamina and enamel organ
It also induces the enamel organ to
differentiate into a particular type of
tooth morphology
91
FORMATIVE
dr. Blagoja Lazovski
The cells of Pulp induces dentin formation
This involves formation of primary and secondary
dentin.
The primary dentin is tubular and regularly
arranged.Formed before root closure
Secondary dentin contain fewer tubules and is
formed after root closure.
92
NUTRITIVE
dr. Blagoja Lazovski
Dental pulp maintains the vitality of dentin by
providing O2 and nutrients to the odontoblasts
Also provides continuing source of dentinal fluid
Nutrition made possible by rich peripheral
capillary network.
93
PROTECTIVE
dr. Blagoja Lazovski
Pulp helps in recognition of stimuli like
heat,cold,pressure,chemicals by way of
sensory nerve fibres.
Vasomotor innervation controls the muscular wall
of blood vessels.This regulates the blood volume
and rate of blood flow and hence the intrapulpal
pressure.
94
DEFENSIVE (OR) REPARATIVE
dr. Blagoja Lazovski
Pulp as remarkable reparative abilities
It responds to irritation by producing reparative dentin and mineralizing and affected dentinal tubules.
Mild to moderate irritation results in continued peritubular dentin formation, sclerosis and intratubular calcifiction-(Tublar sclerosis)
95
dr. Blagoja Lazovski
Stimuli like operative procedures abrasion, caries
can result in rapid dentin formation (Tertiary
dentin)
Inflamed pulp due to bacterial infection the cells
in pulp aid in the process of repair
(macrophages, lymphocycts, neutrophils,
monocytes, plasma , mast cells)
96
PULP OF DECIDUOUS TEETH
dr. Blagoja Lazovski
Overall dimensions smaller
Pulp chambers larger
Roots are long and slender and root canals narrower and follow a tortuous course
Pulp horns at a higher level, especially mesial horns of primary molars
Resorption starts soon after root completion
Root resorption and dentin deposition changes size shape and number of root canals.
97
PRIMARY PULP ORGAN
dr. Blagoja Lazovski
Primary pulp functions for a mean of 8.3 years.
This time can be divided into three periods
Pulp organ growth
Time of crown and root development
Pulp maturation (3 years, 9 months)
Time after root completion to beginning
of root resorption
Pulp regression (3 Years , 6 months)
Beginning of root resorption to exfoliatin
98
REGRESSIVE CHANGES (AGING)
dr. Blagoja Lazovski
Cell Changes
Appearance of fewer cells in aging pulp
Cells are characterized by a decrease in size and no of cytoplasmic organelles
Active pulpal fibrocyte (or) fibroblast has abundant rough-surfaced endoplasmic reticulum notable golgi complex, numerous mitochondria
99
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Fibroblast exhibit less perinuclear cytoplasm, long
thin cytoplasmic processes.
Intra cellular organelles are reduced in no and size
100
FIBROSIS
dr. Blagoja Lazovski
Diffuse fibrillar components
Accumulation of both Bundles of collagen fibres
Fiber bundles may appear arranged longitudinally in the radicular pulp and more diffuse in coronal pup
Collagen accumulation also occurs in some older pulps
Increase in fibers in the pulp organ is gradual and generalized
101
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External trauma such as dental caries (or) deep
restorations cause a localized fibrosis (or) scarring
effect
Increase in collages fibers decrease in the size of
the pulp
Vascular changes occur in aging pulp
102
Pulp Fibrosis
dr. Blagoja Lazovski
103
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Atherosclerotic plaques may appear in pulpal
vessels.
Calcifications are found that surround vessels.
Calcification is found most often in the region
near the apical foramen.
104
Pulp Stones(denticles)
dr. Blagoja Lazovski
Appearing in either or both coronal and root portions of the pulp organ
Develop in teeth that appear to be normal in other respects.
Asymptomatic unless they impinge on nerves (or)blood vessels
Seen in functional as well as embedded unerupted teeth.
105
Classification
dr. Blagoja Lazovski
1. True denticles
2. False denticles
3. Diffuse calcifications
106
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True denticles
True denticles are similar in structure to dentin
They have dental tubules and contain processes of
the odontoblasts
Usually located close to the apical foramen
107
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Development of true denticles is caused by the
inclusion of remnants of the epithelial root sheath
with in the pulp
Epithelial remnants induce the cells of pulp to
differentiate into odentoblasts then form the dentin
mass.
108
True Denticle
H&E section of true denticle
Higher magnification
dr. Blagoja Lazovski
109
False denticles
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They do not exhibit dentinal tubules
They appear as concentric layers of calcified tissue
Some cases these calcification sites appear within
a bundle of collagen fibers.
Some cases they appear in pulp free of collagen
accumulations
110
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Some cases arises around vessels
Center of these concentric layers of calcified tissues
there may be remnants of necrotic and calcified
cells
Calcification of thrombi in blood vessels called
phleholiths, may also serve as nidi for false
denticles
111
dr. Blagoja Lazovski
An denticles begin as small nodules but increase in size by incremental growth
Classified as free, attached (or) embedded depending on their relation to the dentin
a) Free denticle – entirely surrounded by pulp tissue
b) Attached denticle – Partly fused with the dentin
c) Embedded denticles – Entirely surrounded by dentin
Incidence as well as the size of pulp stones increase with age.
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False Denticle
False calcification seen along the walls of the blood
vessel
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Diffuse Calcifications
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Appear as irregular calcific deposits in the pulp
tissue, following collagenous fiber bundles, blood
vessels,
Sometimes they develop into larger mass, persist as
calcified spicules
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These calcifications are usually found in the root
canal and less often in coronal area
These calcification surrounds blood vessels
These calcifications may be classified as
dystrophic calcification
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Diffuse calcification
Diffuse calcification of the pulp, seen along with
pulp fibrosis
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Dystrophic Mineralization
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Ground substance alterations in the dental pulps occurs on aging, such charges may contribute to cellular degeneration and increase dystrophic mineralization.
Circulatory disturbances may be the initiating factor
Mineralizations also seen in the myelin sheaths of nerves.
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Their beginnings are also found in the vessel
walls as in arteriosclerosis.
Older, fibrotic pulp attract mineral salts more
readily.
A mineralized pulp when extirpated, feels
wooden hard.
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Dystropic mineralization due to caries and
periodontal disease
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DM also increase as result of disease processes
such as caries and periodontal diseases
Teeth whose pulps one chronically inflammed
contain DM in regions of previous liquefaction
necrosis.
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Alkaline phosphate in odontoblasts may function
as a calcium pyso phosphatus, there by
stimulating ca2 uptuke in pulps.
Teeth with periodontal disease, DM increase in
both cornonal and radicular pulp.
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AGE CHANGES
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Formation of secondary dentin through out life,
reduces the size of the pulp chamber and root
canals
Decrease in cellularity
Odontoblast decrease in size & number, & may
disappear in certain areas. Especially on pulpal
floor over bifurcation & trifurca
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Increase in number & thickness in collagen fibers
particularly radicular pulp
Reduction in the nerve fibers & blood vessels
Increase resistance of pulp against action of
enzymes
In dentin,
Increase in peritulular dentin
Dentinal sclerosis, reduces permeability
Increase in dead tracts
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Factors infulencing Tertiary
Dentinogenesis
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Reactionary Dentinogenesis:
Shallow cavity- RDT > 0.5mmRD
Deep cavity - RDT 0.25mm - RD
Very deep cavity- RDT 0.008 –0.25mm RD
Reparative Dentinogenesis:
Pulp exposure – RDT< 0.008mm- Reparative dentin
formation.
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Tertiary Dentinogenesis
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CLINICAL CONSIDERATIONS
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1. Anatomic considerations
2. Factors to be considered during endodontic
treatment.
3. Effect of Operative Procedures
4. Effect of dental materials on pulp
5. Effects subsequent to restoration
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ANATOMIC CONSIDERATIONS
dr. Blagoja Lazovski Pulp Chamber with stone Cervical horns
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OPERATIVE PROCEDURES
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Anatomic considerations
1) Shape of the pulp chamber and its extensions into
the cusps pulpal horns is important.
2) Wide pulp chamber into tooth of young person
will make a deep cavity preparation hazardous
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3) The pulpal horns project high into the cusps
exposure of pulp can occur
4) If opening a pulp chamber for treatment its size
and variation in shape must be taken into
consideration
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FACTORS TO BE CONSIDERED DURING
ENTODONTIC TREATMENT
5) Age advance , the pulp chamber becomes
smaller difficult to locate the root canals.
6) Shape of the apical foramen and its location
may play an important part in treatment of root
canals.
7) Accessory canals, and multiple canals are rarely
seen in roentgenograms.
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FACTORS TO BE CONSIDERED DURING OPERATIVE
PROCEDURES
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8) The pulp is highly responsive to stimuli, even slight
stimulus cause inflammatory cell infiltration.
9) Dehydration causes pulpal damage operative
procedures producing this condition should be
avoided.
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Filling material contain harm ful chemicals
Silicate cement - acid
Composites - monomer
Vital pulp is essential to good dentition.
Now vital tooth becomes brittle and is subject to
fracture.
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EFFECT OF DENTAL MATERIALS ON PULP
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GIC – Well tolerated by pulp
Calcium hydroxide – includes dentin bridge formation.
Zine oxide – eugenol- has an anti-bacterial effect.
Formocresol – Cause chronic inflammation of the pulp.
Dentin bonding agent – can irritate the pulp causing
inflammation
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DETECTION OF PULP VITALITY
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Electric pulp testing
More accurate than some of the tests used to
detamine pulp vitality
Heat testing
Thermal testing
Cold
Anesthetic testing
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Anesthetic testing
Test cavity
This test performed when other methods of diagnosis have failed
The test cavity is made drilling through enamel – dentin junction of an unanaesthetized tooth
Pulse oximeter
Based on evaluating oxygen saturation of the tissue.
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CONCUSION
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THE PRESEVATION OF A HEALTHY PULP DURING
OPERATIVE PROCEDURES AND SUCCESSFUL
MANAGEMENT IN CASES OF DISEASES ARE TWO
OF MOST IMPORTANT CHALLENGE TO THE
CLINICAL DENTIST.
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