Prof Essam soussa

1. BYBY
PROF.DR.ESSAM SOUSSAPROF.DR.ESSAM SOUSSA
BDS,MS,PHD.BDS,MS,PHD.

2. What is theWhat is the
dental pulpdental pulp
tissuetissue??

3. WarningWarning::
The Pulp Content Advisory BoardThe Pulp Content Advisory Board
has rated this lecturehas rated this lecture::

4. Like the pulpLike the pulp

5. OutlineOutline
 Anatomy of the pulpAnatomy of the pulp
 Histology of the pulpHistology of the pulp
 OdontoblastOdontoblast
 FibroblastFibroblast
 CellsCells
 Fibers and ground substanceFibers and ground substance
 VascularityVascularity
 nervesnerves
 Pain and the pulp-dentin complexPain and the pulp-dentin complex
 Function of pulpFunction of pulp
 Age changesAge changes

6. PulpPulp
The dental pulp isThe dental pulp is
that loose delicatethat loose delicate
connective tissueconnective tissue
occupying theoccupying the
cavity lying in thecavity lying in the
center of dentin.center of dentin.

7. From where itFrom where it
comecome??
What are the origin?What are the origin?

8. Origin of the PulpOrigin of the Pulp
 Condensed Ectomesenchyme.Condensed Ectomesenchyme.
 Dental PapillaDental Papilla
88

9. Development:Development:
 The dental pulp develops in
the eighth week of I.U.L. in the
anterior teeth, while in the
posterior teeth it begins later.
 At first the tooth pulp is known
as the dental papilla, is known
as pulp after dentin forms
around it.
 The dental papilla controls
early tooth formation and
morphology, so it causes the
oral epithelium to invaginate
and forms the enamel organ.

10.  The young dental papilla is highly vascular andThe young dental papilla is highly vascular and
the cells of the dental papilla gradually developthe cells of the dental papilla gradually develop
intointo star shapedstar shaped,, roundedrounded oror spindle shapedspindle shaped
fibroblastsfibroblasts..
 The Odontoblasts differentiate from theThe Odontoblasts differentiate from the
peripheral cells of the dental papilla.peripheral cells of the dental papilla.
 Few largeFew large myelinatedmyelinated nerves are found in thenerves are found in the
pulp when the dentin of the crown is wellpulp when the dentin of the crown is well
advanced.advanced.
 TheThe sympatheticsympathetic nerves follow the bloodnerves follow the blood
vessels into the pulp.vessels into the pulp.

11. Did you must know theDid you must know the
shape of the pulpshape of the pulp
cavities?cavities?
WhyWhy??

12. MorphologyMorphology
 Each pulp organ isEach pulp organ is
composed of acomposed of a
coronal pulpcoronal pulp
located centrallylocated centrally
in the crowns ofin the crowns of
teeth and the rootteeth and the root
oror radicular pulp.radicular pulp.

13. The coronal pulp:The coronal pulp:
 it is present in theit is present in the pulppulp
chamberchamber, in young, in young
individuals it resembles theindividuals it resembles the
shape of the outer surfaceshape of the outer surface
of the crown dentin and notof the crown dentin and not
the outer surface ofthe outer surface of
enamel.enamel.
 It hasIt has pulp hornspulp horns which arewhich are
protrusions that extend intoprotrusions that extend into
the cusp of each tooth.the cusp of each tooth.
 Due to the continuousDue to the continuous
deposition of dentindeposition of dentin
throughout life, the size ofthroughout life, the size of
the pulp chamber graduallythe pulp chamber gradually
decreasesdecreases and obliterationand obliteration
of the pulp horns occurs.of the pulp horns occurs.

14. The radicular pulp:The radicular pulp:
 it is that part of the pulpit is that part of the pulp
extending from the cervicalextending from the cervical
region of the crown to the rootregion of the crown to the root
apex.apex.
 In the anterior teeth theIn the anterior teeth the
radicular pulpsradicular pulps are singleare single andand
in the posterior ones they arein the posterior ones they are
multiplemultiple..
 The outline of the radicularThe outline of the radicular
pulp conforms with the dentino-pulp conforms with the dentino-
cemental junction.cemental junction.

15.  During root formation,During root formation, apicalapical
root end is wideroot end is wide limited bylimited by
the epithelial diaphragm, itthe epithelial diaphragm, it
resembles a wide open tube.resembles a wide open tube.
 With the complete formation ofWith the complete formation of
the root, the root canalthe root, the root canal
becomesbecomes tapering andtapering and
narrowednarrowed..
 Further narrowing of the apicalFurther narrowing of the apical
foramen may be produced byforamen may be produced by
the depositionthe deposition of cementumof cementum
inside the foramen.inside the foramen.

16.  The radicular portions of theThe radicular portions of the
pulp organs are continuous withpulp organs are continuous with
the periapical connective tissuethe periapical connective tissue
through the apical foramen.through the apical foramen.
 The average size of the apicalThe average size of the apical
foramen of theforamen of the maxillarymaxillary teethteeth
in the adult isin the adult is 0.4 mm0.4 mm, while in, while in
thethe mandibularmandibular teeth it isteeth it is 0.3mm0.3mm
in diameter.in diameter.
Apical foramen:Apical foramen:

17. Anatomy of the “Pulp SpaceAnatomy of the “Pulp Space””
1717

18. Accessory canals:Accessory canals:
 Are commonly seen to extendAre commonly seen to extend
from the radicular pulpfrom the radicular pulp
laterally through the rootlaterally through the root
dentin to the periodontaldentin to the periodontal
ligament.ligament.
 They are numerous in theThey are numerous in the
apical thirdapical third of the root.of the root.

19. Mechanism of formation of accessoryMechanism of formation of accessory
canals is unknown but it is more likely tocanals is unknown but it is more likely to
occur.occur.
1-1- In areas, where the developing rootIn areas, where the developing root
encounters a largeencounters a large blood vesselblood vessel, where, where
dentin will be formed around it, thendentin will be formed around it, then
making the lateral canal or canals.making the lateral canal or canals.
2- Early degeneration of the epithelial2- Early degeneration of the epithelial rootroot
sheath of Hertwigsheath of Hertwig before thebefore the
differentiation of the Odontoblasts willdifferentiation of the Odontoblasts will
also lead to the formation of accessoryalso lead to the formation of accessory
root canal.root canal.

20. 3-Lack of complete union of the3-Lack of complete union of the epithelialepithelial
diaphragmdiaphragm at the floor of the pulpat the floor of the pulp
chamber is another possibility which willchamber is another possibility which will
lead to the formation of accessory rootlead to the formation of accessory root
canal in the area of root furcation.canal in the area of root furcation.

21. Accessory canalsAccessory canals::
2121

22. Structures ,Structures ,
is it important?is it important?

23. Histological structureHistological structure
 The dental pulp is formed ofThe dental pulp is formed of
specialize loose connectivespecialize loose connective
tissue.tissue.
 It is formed of cells, fibers,It is formed of cells, fibers,
intercellularintercellular substances,substances,
blood vessels and nerves.blood vessels and nerves.
 The intercellular substance isThe intercellular substance is
dense and gel like indense and gel like in
consistency and varies inconsistency and varies in
appearance from finelyappearance from finely
granular to fibrilar.granular to fibrilar.
 It is formed ofIt is formed of acidacid
mucopolysaccharides &mucopolysaccharides &
glycoproteinglycoprotein’’ss..

24. PulpPulp
The body of the pulpThe body of the pulp
constitutes of theconstitutes of the
connective tissueconnective tissue
which occupies thewhich occupies the
space in the pulpspace in the pulp
chamber, although thechamber, although the
matrix comprisedmatrix comprised
mainly ofmainly of type Itype I
collagen relativelycollagen relatively
highhigh type IItype II in additionin addition
toto proteoglycanproteoglycan..

25.  Although theAlthough the
predominant cells typepredominant cells type
content is thecontent is the
fibroblastfibroblast than thethan the
undifferentiatedundifferentiated
mesenchymemesenchyme..
 The macrophages mayThe macrophages may
be present in inflamedbe present in inflamed
pulp, located sub-pulp, located sub-
odontoblastic regionodontoblastic region

26.  Which contains theWhich contains the nervesnerves andand
capillariescapillaries these enter the pulpthese enter the pulp
through the apical foramen tothrough the apical foramen to
supply the odontoblast layer assupply the odontoblast layer as
well as the pulp itself.well as the pulp itself.

27. • Maintain tissue’s physical properties and
integrity
• Control of growth and development and
repairs
• Control of cell migration
• Control of diffusion of macromoleculesControl of diffusion of macromolecules
FunctionsFunctions
ofof
pulpal extracellular matrixpulpal extracellular matrix

28. PredentinePredentine
 TheThe predentinepredentine is theis the
initial matrix of theinitial matrix of the
collagenous dentinecollagenous dentine
before it is mineralized.before it is mineralized.
 There is always a layer ofThere is always a layer of
the predentine betweenthe predentine between
thethe Odontoblast layerOdontoblast layer andand
thethe mineralized dentinemineralized dentine ..
 Homologous to theHomologous to the
osteoid on the surface ofosteoid on the surface of
the forming bone.the forming bone.

29. Pulp
Organization
– Odontoblastic Zone
– Cell-Free Zone
(Weil)
– Cell-Rich Zone
– Pulp Core
2929

30. Pulp Organization
Odontoblastic
Zone
3030

31. Pulp Organization
Cell-
Free
Zone
3131

32. Pulp Organization
Cell-
Rich
Zone
3232

33. Pulp Organization
Pulp
Core
3333

34. I-I- Cells of the PulpCells of the Pulp
The cells of the pulp may be divided into:The cells of the pulp may be divided into:
I-Synthetic cells:I-Synthetic cells: (formative cells):(formative cells):
Odontoblasts and fibroblasts.Odontoblasts and fibroblasts.
2-Defensive cells:2-Defensive cells: HistiocytesHistiocytes
(macrophages) small lymphocytes,(macrophages) small lymphocytes,
eosinophils, mast cells and plasma cells.eosinophils, mast cells and plasma cells.
3-Progenitor cells:3-Progenitor cells: UndifferentiatedUndifferentiated
mesenchymal cells.mesenchymal cells.

35. 1-1- Synthetic cells:Synthetic cells:

36. Odontoblasts:Odontoblasts:
 The Odontoblasts areThe Odontoblasts are
found adjacent to thefound adjacent to the
predentin with the cellspredentin with the cells
bodies in the pulp andbodies in the pulp and
cell processes in thecell processes in the
dentinal tubules.dentinal tubules.
 They are approximatelyThey are approximately
5-7u in diameter and5-7u in diameter and
about 25 - 40u inabout 25 - 40u in

37.  The shape andThe shape and
arrangement of thearrangement of the
cell bodies vary withcell bodies vary with
the stage of tooththe stage of tooth
development.development.
 It consists of a singleIt consists of a single
layer of cells in thelayer of cells in the
early stage of dentinearly stage of dentin
formation where theformation where the
cells are regularlycells are regularly
arranged and ofarranged and of
moderate length.moderate length.

38.  In the later stagesIn the later stages
of development,of development,
the odontoblasticthe odontoblastic
layer is muchlayer is much
broader, the cellsbroader, the cells
are less columnarare less columnar
and tend to beand tend to be
pyriformpyriform where thewhere the
broadest pan ofbroadest pan of
the cell containsthe cell contains
the nucleus.the nucleus.

39. OdontoblastOdontoblast
 Is the cells responsible for forming dentine andIs the cells responsible for forming dentine and
thethe PredentinePredentine , it initially secretes a collagenous, it initially secretes a collagenous
matrix which then subsequently mineralized.matrix which then subsequently mineralized.

40.  Also a great number of vesicles are seen
along the periphery of the process.
 While near the pulpal predentin junction
the cell cytoplasm is devoid of organelles.

41.  Immediately beneath theImmediately beneath the odontoblasticodontoblastic layer alayer a
cell free zone can often be demonstrated,cell free zone can often be demonstrated,
Some believe that theSome believe that the cell free zonecell free zone is theis the
area of mobilization and replacement ofarea of mobilization and replacement of
Odontoblasts.Odontoblasts.
 and this may explain why this zone is not clearand this may explain why this zone is not clear
during early stages of rapidduring early stages of rapid dentinogenesisdentinogenesis ..

42.  Beneath the cell free
zone, if present, there
is a narrow zone of
pulp tissue, this is a
rich cell zone.
 The Odontogenic zone
is composed of the
Odontoblasts, the cell
free zone and the cell
rich zone.
 The cell rich zone is
composed mainly of
fibroblasts and
undifferentiated
mesenchymal cells.

43. Cell free zone (of Weil)Cell free zone (of Weil)
• The cell free zone appears devoid of cells
on its typical however, it can be seen that
while it may not contain many cells nuclei
it has numerous cell processes running
through it sub-odontoblastic layer .
• also many small capillaries loops run
through it as they odontoblastic capillary
plexus

44. Cell rich zoneCell rich zone
 The cell rich zoneThe cell rich zone
unlike the nameunlike the name
suggests ,this zonesuggests ,this zone
appears to contains aappears to contains a
high concentration ofhigh concentration of
the cell nucleithe cell nuclei

45. b-b- Fibroblasts:Fibroblasts:
 These are the most
numerous type of cells.
 They are spindle in
shape with elongated
processes which are
widely separated and
link up with those of
other pulpal
fibroblasts.
 These processes give
the cells a stellate

46.  The nucleus stainsThe nucleus stains
deep with basic dyedeep with basic dye
and the cytoplasm isand the cytoplasm is
highly stained andhighly stained and
homogenous.homogenous.
 These cells have aThese cells have a
dual functiondual function (for(for
both synthesize andboth synthesize and
degradation of fibers)degradation of fibers)
in the same cellin the same cell..

47. Synthesis of collagen and its assembly into fibrils and fiber

48. 2- Defensive cells:2- Defensive cells:

49. a- Histocyte or tissuea- Histocyte or tissue
macrophage cell:macrophage cell:
 InIn light microscopelight microscope, the cells appear, the cells appear irregular inirregular in
shapeshape with short blunt processes.with short blunt processes.
 TheThe nucleus is smallnucleus is small, more rounded and darker, more rounded and darker
in staining than that of fibroblast.in staining than that of fibroblast.
 These cells are usually withThese cells are usually with small bloodsmall blood vesselsvessels
andand capillariescapillaries ..

50.  Their presence is disclosed by intra-vital
dyes such trypan blue.
 In case of inflammatioinflammation, it exhibits
granules and vacuoles in their cytoplasm
and their nuclei, increase in size and
exhibit a prominent nucleolus.
 Invaginations of plasma membrane are
noted ultra-structurally with aggregation
of vesicles or phagosomesphagosomes which
contain phagocytozedphagocytozed dense irregular
bodies.

51. b-b- Plasma cells:Plasma cells:
 These cells are seen duringThese cells are seen during
inflammationinflammation..
 The nucleus of this cell is small andThe nucleus of this cell is small and
appears concentric in the cytoplasm.appears concentric in the cytoplasm.
 The arrangement of chromatin in theThe arrangement of chromatin in the
nucleus gives the cell anucleus gives the cell a car wheelcar wheel
appearance, both mature andappearance, both mature and
immature cells may be found.immature cells may be found.

52.  The mature type exhibits a typical smallThe mature type exhibits a typical small
eccentric nucleus and more abundanteccentric nucleus and more abundant
cytoplasm.cytoplasm.
 The plasma cells are known to produceThe plasma cells are known to produce
antibodiesantibodies..

53. c- Lymphocytes and Eosinophils:c- Lymphocytes and Eosinophils:
 They are found inThey are found in
normal pulp and theynormal pulp and they
increase duringincrease during
inflammationinflammation..

54. d- Mast cells:d- Mast cells:
 May be present, theyMay be present, they
have a round nucleus andhave a round nucleus and
their cytoplasm containstheir cytoplasm contains
manymany granulesgranules..
 They are demonstratedThey are demonstrated
by using specific stainsby using specific stains
asas toluidine bluetoluidine blue ..
 Histamine is releasedHistamine is released
 Mast cells release histamine when anMast cells release histamine when an
allergen is encountered. The histamineallergen is encountered. The histamine
response can produce sneezing,response can produce sneezing,
itching, hives and watery eyes.itching, hives and watery eyes.

55. 3- Progenitor cells3- Progenitor cells
(The undifferentiated mesenchymal cells):(The undifferentiated mesenchymal cells):

56.  They are smaller thanThey are smaller than
the fibroblasts butthe fibroblasts but
have a similarhave a similar
appearance.appearance.
 They are usuallyThey are usually
foundfound along thealong the
wallswalls ofof bloodblood
vesselsvessels..
 These cells have theThese cells have the
potentialitypotentiality of formingof forming
other types ofother types of
formative or defensiveformative or defensive
connective tissue cellsconnective tissue cells

57. II- The fibers and groundII- The fibers and ground
substances:substances:

58.  The collagen fibersThe collagen fibers
in an extra cellularin an extra cellular
ground substancesground substances
surround the cellssurround the cells
of the pulp.of the pulp.
 BothBoth types I and IItypes I and II
collagencollagen have beenhave been
found in the pulp,found in the pulp,
both types areboth types are
produced byproduced by
fibroblasts.fibroblasts.

59. FibroblastFibroblast
 In young pulp theIn young pulp the
fibers arefibers are
relatively sparserelatively sparse
and delicateand delicate
throughout thethroughout the
pulp and graduallypulp and gradually
the bundlesthe bundles
increase in sizeincrease in size
with advancingwith advancing
age, Where inage, Where in
older pulp twoolder pulp two
patterns ofpatterns of

60.  ItIt’’s distribution can be seen, one is a diffuses distribution can be seen, one is a diffuse
collagen network with no definite orientation.collagen network with no definite orientation.
 The other is bundles of collagen, There areThe other is bundles of collagen, There are
no elastic fibersno elastic fibers in the pulpin the pulp exceptexcept thosethose
present in the walls of thepresent in the walls of the larger bloodlarger blood
vesselsvessels..
 The ground substances consist of acidThe ground substances consist of acid
mucopolysaccharidesmucopolysaccharides and neutraland neutral
glycoproteinglycoprotein these substances are thethese substances are the
environment that promotes life of the cells.environment that promotes life of the cells.

61. III- Blood vessels andIII- Blood vessels and
nerves:nerves:

62.  The pulp isThe pulp is highly vascularizedhighly vascularized ..
 It is supplied by theIt is supplied by the inferior and superiorinferior and superior
alveolar arteriesalveolar arteries and drained by the sameand drained by the same
veinsveins in both mandibular and maxillaryin both mandibular and maxillary
regions.regions.
 The branches of alveolar arteries whichThe branches of alveolar arteries which
enter the tooth and its supporting tissuesenter the tooth and its supporting tissues
are different in its structures.are different in its structures.

63. Vasculature of the Pulp
 Apical Foramen Area
 Arteriolar Size (≈ 150µm)
 Afferent & Efferent Vessels
 Arterioles, Venules, Lymphatics
 Radicular Pulp
 Central Location, Larger Lumen
 Coronal Pulp
 Extensive Vascular Capillary Network
6363

64. Pulp vasculature

65.  As the vessels enter the tooth,
their walls become
considerably thinner than
those surrounding the tooth.
 Small arteries which enter the
apical canal run in a direct
route to the coronal pulp.
 Along their course they give
off numerous branches in the
radicular pulp that pass
peripherally to form a plexus
in the odontogenic region.
 The pulpal blood flow is more
rapid than in most areas of the
body.

66. Veins and veinulesVeins and veinules
 Are larger than the arteries also appear
in the central region of the root pulp.
 Veins measure 100-150u in diameter and
their wall appear less regular and thin.
 The endothelial cells, lining these
vessels appear more flattened and do
not project into the lumen.

67. Lymph vesselsLymph vessels::
 Blind-EndedBlind-Ended
 Thin WalledThin Walled
 DiscontinuitiesDiscontinuities
 No Basal LaminaNo Basal Lamina
 Tissue Fluid PressureTissue Fluid Pressure
 The draining of the anterior
teeth pass to the submental
lymph nodes, those of the
posterior teeth pass to the
submandibular and deep
cervical lymph nodes.

68. Nerves:Nerves:

69. The pulp has an abundant nerve supply whichThe pulp has an abundant nerve supply which
follows the distribution of the blood vessels.follows the distribution of the blood vessels.
Two types of nerve fibers are presentTwo types of nerve fibers are present ::
1-The non-myelinated1-The non-myelinated
nerves fibers:nerves fibers:
which are found in, close
association with the
blood vessels of the
pulp and are
sympathetic in nature
where they control the
contraction of the
smooth muscles present
in their lumen.

70. 2-2- Myelinated nerves fibers:Myelinated nerves fibers:
 Which are sensory
parasympathetic
nerves and they carry
sensation to the
sensory cortex of the
brain.
 The nerve fibers enter
the apical foramen and
divide into many
branches till reaching
peripherally the cell
rich zone, where they
lose their myelin
sheath.

71.  The peripheral axons
form a network of
nerves located
adjacent to the cell-
rich zone.
 This is termed the
“parietal layer of
nerves” or plexus of
Raschkow.

72. Approx. 1800 non
myelinated +
400 myelinated
Intradentinal nerves are mostly found in
pulpal horns.

73.  These nerve
fibers either
terminate among
or pass between
the Odontoblasts
where they then
terminate
adjacent to the
odontoblastic
processes at the
pulp predentin
border or in the
dentinal tubules.

74.  More nerve
endings are
found in the
pulp horns
than in other
peripheral
areas of the
coronal or
radicular pulp.

75. Theories of pain transmission:Theories of pain transmission:
(1) Direct neural(1) Direct neural
theory.theory.
(2) Fluid or(2) Fluid or
hydrodynamichydrodynamic
theory.theory.
(3) Odontoblasts(3) Odontoblasts
transductiontransduction
theory.theory.
7575

76. Pulp venules
STIMULATION
Increased pulp
interstitial fluid
Increased pulp
pressure
Increased tubular
fluid flow
Release of
inflammatory
agents?
Increased blood
viscosity and rbc
congestion in
capillary bed
Increased A-V shunt
blood flow
Outward dentinal
fluid flow and
aspiration of
odontoblasts
CNS, Pain,
Vasodilation, Increased permeability
Pulpal axonal reflex due to dentine
stimulation
Without infection,
Vascular changes could
be resolved.
Without infection,
Vascular changes could
be resolved.
Axon
reflex
SP, CGRP
Dentine

77. Function:Function:

78. 1- Inductive:1- Inductive:
Pulp anlage (dental papilla)
induces the enamel organ
formation and also determines the
morphology of the tooth formed
whether an anterior or a posterior
tooth.
2- Formative:2- Formative:
 Pulp organ produces dentin.
 The pulpal Odontoblasts develop
the organic matrix and function in
its calcification.

79. 3-3- Nutritive:Nutritive:
The pulp nourishes the dentin. The
nutritional elements are contained in the
tissue fluid. Nutrition is mediated to the
dentin through the Odontoblasts and their
processes.
4-4- Protective:Protective:
The sensory nerves in the tooth respond
with pain to all stimuli such as heat, cold,
pressure, chemical agents and operative
cutting procedures. Pain sensation is a
useful alarm system of the pulp.

80. 5- Defensive or reparative:5- Defensive or reparative:
The pulp that responds to irritation byThe pulp that responds to irritation by
producing reparative dentin andproducing reparative dentin and
mineralizing any affected dentinal tubules.mineralizing any affected dentinal tubules.
These reparative or defensive reactions areThese reparative or defensive reactions are
an attempt to wall off the pulp from thean attempt to wall off the pulp from the
source of irritation.source of irritation.
Also the presence of macrophages,Also the presence of macrophages,
lymphocytes and leucocytes aid in thelymphocytes and leucocytes aid in the
process of repair of the pulp.process of repair of the pulp.

81. Age changes in the pulpAge changes in the pulp

82. 1-With advancing age, there is continuous1-With advancing age, there is continuous
formation of dentin structure with the resultformation of dentin structure with the result
that thethat the size of the pulp chambersize of the pulp chamber as wellas well
as the root canals isas the root canals is reducedreduced..
TheThe apical foramenapical foramen is wide open in theis wide open in the
young tooth but becomesyoung tooth but becomes narrowednarrowed withwith
age and is further constricted byage and is further constricted by
cementum formationcementum formation

83. 2-In embryonic pulp the2-In embryonic pulp the cellular elementscellular elements
are predominant, while with advancingare predominant, while with advancing
age the pulp, becomesage the pulp, becomes poorerpoorer in cells andin cells and
shows an increase in collagenous fibrillarshows an increase in collagenous fibrillar
masses which are arranged in bundles,masses which are arranged in bundles,
fewer undifferentiated cells available arefewer undifferentiated cells available are
for emergencies, so the defense andfor emergencies, so the defense and
repair processes are slower in gettingrepair processes are slower in getting
started.started.

84. 3-In old pulp the3-In old pulp the blood vessels and nerveblood vessels and nerve
bundles are alsobundles are also decreaseddecreased..
4-Reticular atrophy:4-Reticular atrophy:
In these changes theIn these changes the OdontoblastsOdontoblasts areare
affected andaffected and tend to degeneratetend to degenerate, in some, in some
areas of the pulp they may haveareas of the pulp they may have
completely disappeared, vacuoles maycompletely disappeared, vacuoles may
result.result.
The total effect is the production of aThe total effect is the production of a
lessened vitality of the pulp tissue and alessened vitality of the pulp tissue and a
lessened response to stimulation (reticularlessened response to stimulation (reticular
atrophy).atrophy).

85. 5-Pulp calcification :5-Pulp calcification :
 A further change associated with aging is theA further change associated with aging is the
appearance ofappearance of deposits of calciumdeposits of calcium in the pulp.in the pulp.
 These deposits may be in the form of localizedThese deposits may be in the form of localized
masses known as pulpmasses known as pulp stonesstones oror denticlesdenticles,,
sometimes large enough to be seen in an x-ray, orsometimes large enough to be seen in an x-ray, or
alternatively as diffuse calcifications throughoutalternatively as diffuse calcifications throughout
the whole pulp.the whole pulp.

86. Pulp stonesPulp stones

87. Stones or denticlesStones or denticles
Denticles as well as diffuse calcificationDenticles as well as diffuse calcification
maybe found also in young and normalmaybe found also in young and normal
pulp and they tend to increase both inpulp and they tend to increase both in
size and number with advance of age,size and number with advance of age,
pulp stones are classified, according topulp stones are classified, according to
their structure astheir structure as true and false denticles.true and false denticles.

88. Decalcified section of a toothDecalcified section of a tooth
(Hx.E) showing(Hx.E) showing
1.1. DentinDentin
2.2. Attached pulpAttached pulp
stonestone
3.3. PulpPulp
4.4. free pulpfree pulp
stonestone

89. 1.1. DevelopmentDevelopment
 Epithelio-Mesenchymal InteractionsEpithelio-Mesenchymal Interactions ..
Small groups of epithelial cells becomeSmall groups of epithelial cells become
isolated from the epithelial root sheathisolated from the epithelial root sheath
during development and end up in theduring development and end up in the
dental papilla. Here they interact withdental papilla. Here they interact with
mesenchymal cells resulting in theirmesenchymal cells resulting in their
differentiation into odontoblasts. They formdifferentiation into odontoblasts. They form
small dentinal structures within the pulp.small dentinal structures within the pulp.

90.  Calcific DegenerationsCalcific Degenerations ..
Spontaneous calcification of pulpSpontaneous calcification of pulp
components (collagen fibers, groundcomponents (collagen fibers, ground
substance, cell debris, etc.) may expandsubstance, cell debris, etc.) may expand
or induce pulpal cells into osteoblasts.or induce pulpal cells into osteoblasts.
These cells then produce concentricThese cells then produce concentric
layers of calcifying matrix on the surface oflayers of calcifying matrix on the surface of
the mass - but no cells become entrapped.the mass - but no cells become entrapped.

91.  Diffuse CalcificationDiffuse Calcification ..
A variation of the above whereby seriouslyA variation of the above whereby seriously
degenerated pulp undergoes calcificationdegenerated pulp undergoes calcification
in a number of locations. These bodiesin a number of locations. These bodies
resemble calcific degenerations except forresemble calcific degenerations except for
their smaller size and increased number.their smaller size and increased number.

92. 22..HistologyHistology
 Calcified bodies in the pulp may beCalcified bodies in the pulp may be
composed ofcomposed of dentin, irregularlydentin, irregularly
calcified tissuecalcified tissue , or, or bothboth.. A calcifiedA calcified
body containing tubular dentin is referredbody containing tubular dentin is referred
to as ato as a "true" pulp stone or denticle."true" pulp stone or denticle.
 True pulp stones exhibit radiatingTrue pulp stones exhibit radiating
striations reminiscent of dentinal tubules.striations reminiscent of dentinal tubules.
Usually those bodies formed by anUsually those bodies formed by an
epithelio- mesenchymal interaction, areepithelio- mesenchymal interaction, are
true pulp stones.true pulp stones.

93.  Irregularly calcified tissue generally doesIrregularly calcified tissue generally does
not bear much resemblance to any knownnot bear much resemblance to any known
tissue and as such is referred to as atissue and as such is referred to as a
"false" pulp stone"false" pulp stone oror denticledenticle ..
 False pulp stones generally exhibit eitherFalse pulp stones generally exhibit either
a hyaline-like homogeneous morphologya hyaline-like homogeneous morphology
or appear to be composed of concentricor appear to be composed of concentric
lamellae.lamellae.

94. True denticlesTrue denticles consist ofconsist of
irregular dentin containingirregular dentin containing
traces of dentinal tubulestraces of dentinal tubules
and few odontoblasts.and few odontoblasts.
 The development of thisThe development of this
true denticle is nottrue denticle is not
completely understood.completely understood.
 It has been postulated thatIt has been postulated that
during root formationduring root formation
developmentaldevelopmental
disturbances causingdisturbances causing
remnants of the epithelialremnants of the epithelial
root of Hertwig to invaderoot of Hertwig to invade
the pulp tissues causingthe pulp tissues causing
undifferentiatedundifferentiated
mesenchymal cellsmesenchymal cells

95.  Both types of stonesBoth types of stones::
AA andand BB are false pulp stones,are false pulp stones, CC
is a true pulp stone.is a true pulp stone.
AA is an "attached" stone (whichis an "attached" stone (which
may become embedded asmay become embedded as
secondary dentin depositionsecondary dentin deposition
continues.continues.
BB andand CC are "free" stones foundare "free" stones found
within the pulp cavity.within the pulp cavity.

96. True Pulp StoneTrue Pulp Stone
 LegendLegend AA - true pulp- true pulp
stonestone
 BB - dentinal tubules- dentinal tubules

97.  If the pulp to form thisIf the pulp to form this
irregular type ofirregular type of
dentin.dentin.
 Tine denticles areTine denticles are
rare to occur, they arerare to occur, they are
small in size andsmall in size and
commonly found in thecommonly found in the
root canal near theroot canal near the
apical foramen.apical foramen.

98. The false denticlesThe false denticles are evidence ofare evidence of
dystrophic calcification of the pulpdystrophic calcification of the pulp
tissue .tissue .
 They containThey contain no dentinal tubulesno dentinal tubules ..
 They are formed of degeneratedThey are formed of degenerated
cells or areas of hemorrhagecells or areas of hemorrhage
which act as a centralwhich act as a central nidusnidus
favoring the deposition offavoring the deposition of
concentric layers in typicalconcentric layers in typical
calcospherite form and continue tocalcospherite form and continue to
increase in size and in certainincrease in size and in certain
cases they fill up the pulp chambercases they fill up the pulp chamber
completely.completely.
 Overdoses of vit. DOverdoses of vit. D , may favor the, may favor the
formation of numerous denticles.formation of numerous denticles.

99. False Pulp StoneFalse Pulp Stone
 LegendLegend AA - pulp- pulp
BB - dentin- dentin
 CC - false pulp stone- false pulp stone

100. Fig. IVA-3: Section through a human tooth pulp whichFig. IVA-3: Section through a human tooth pulp which
contains a number of calcified bodies (pulp stones).contains a number of calcified bodies (pulp stones).
Dentin and odontoblasts are visible at the right.Dentin and odontoblasts are visible at the right.

101.  Pulp stones are classifiedPulp stones are classified
according to their location inaccording to their location in
relation to the wall of the pulprelation to the wall of the pulp
cavity.cavity.
 All denticles are classified asAll denticles are classified as
being free, attached andbeing free, attached and
interstitial or embedded, freeinterstitial or embedded, free
denficles are so called when theydenficles are so called when they
are completely surrounded withare completely surrounded with
normal pulp tissue, interstitialnormal pulp tissue, interstitial
denticles are embedded withindenticles are embedded within
the dentin and have developed bythe dentin and have developed by
the continued formation of dentinthe continued formation of dentin
around an attached denticle.around an attached denticle. false pulp stone
ConclusionConclusion

102.  If pulp stones come close enough toIf pulp stones come close enough to
a nerve bundle causing pressure,a nerve bundle causing pressure,
pain may be elicited.pain may be elicited.
 This idea is not universallyThis idea is not universally
accepted, because teeth are seenaccepted, because teeth are seen
in which the pulp is laden with pulpin which the pulp is laden with pulp
stones without producing any pain.stones without producing any pain.
 The close proximity of pulp stonesThe close proximity of pulp stones
to blood vessels may cause atrophyto blood vessels may cause atrophy
of it, if the growing pulp stonesof it, if the growing pulp stones
exert pressure upon the vessels.exert pressure upon the vessels.

103.  Diffuse pulp calcificationDiffuse pulp calcification
commonly occurs on top ofcommonly occurs on top of
hyaline degeneration in thehyaline degeneration in the
root canal and not commonroot canal and not common
in the pulp chamber.in the pulp chamber.
 They are amorphous andThey are amorphous and
have no specific structure.have no specific structure.
 They are irregular calcificThey are irregular calcific
deposition in the pulp tissuedeposition in the pulp tissue
following the course of bloodfollowing the course of blood
vessels or collagenousvessels or collagenous
bundle.bundle.
 Also advancing age favorsAlso advancing age favors
their development.their development.

106. Oral Biology &Oral Biology &
DentalDental
MorphologyMorphology
MansouraMansoura
UniversityUniversity

107. Learning ObjectivesLearning Objectives
1.1. How much inorganic material does normal dental pulp contain? WhatHow much inorganic material does normal dental pulp contain? What
three features common to CT compose the pulp? Which type ofthree features common to CT compose the pulp? Which type of
collagen fibers are found here?collagen fibers are found here?
2.2. Be able to label a diagram of the architecture of the pulp. Where is theBe able to label a diagram of the architecture of the pulp. Where is the
cell-free zone located? What composes the odontogenic layer? Incell-free zone located? What composes the odontogenic layer? In
which layer is the neural plexus located? Where is the cell-rich zone?which layer is the neural plexus located? Where is the cell-rich zone?
What types of cells predominate in this layer?What types of cells predominate in this layer?
3.3. The dense capillary network under the odontoblasts reflect whatThe dense capillary network under the odontoblasts reflect what
feature of this layer? Is there a lymphatic drainage of the pulp? Wherefeature of this layer? Is there a lymphatic drainage of the pulp? Where
does tissue fluid drain in lieu of them?does tissue fluid drain in lieu of them?
4.4. List the two types of nerve fibers found in the pulp and the specificList the two types of nerve fibers found in the pulp and the specific
function of each. With regard to the sensory fibers. Where to thefunction of each. With regard to the sensory fibers. Where to the
myelinated fibers terminate? What type of pain is referred bymyelinated fibers terminate? What type of pain is referred by
myelinated fibers? from unmyelinated fibers?myelinated fibers? from unmyelinated fibers?
5.5. What are the two types of pulp? Do they differ in composition? WhereWhat are the two types of pulp? Do they differ in composition? Where
would a pulp horn be found?would a pulp horn be found?
6.6. What age-related changes occur in the pulp? Why?What age-related changes occur in the pulp? Why?
7.7. What are pulp stones? How are they thought to develop? What are theWhat are pulp stones? How are they thought to develop? What are the
two types of pulp stones and how can you distinguish one from thetwo types of pulp stones and how can you distinguish one from the
other?other?