oral histology compendium

8/9/2019 Oral Histology Compendium

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ORAL TISSUE AGING: processes

More stuff e.g. fibrosis & fat tissue

Less stuff e.g. wear of enamel

Misplaced e.g. gingival recession

Bad stuff e.g. collagen stiffer & lessdigestible; DNA mutated

Imbalance e.g. OSTEOCLASTS:osteoblasts

Compensation e.g. apical cementum

WABeresford

AGING ENAMEL

P

ULP

ATTRITION/ WEAR

More translucent = darker

MORE BRITTLE

reduced permeability

More resistant to caries?Changes in ion composition


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PULP

AGING in DENTINE

CIRCUMPULPAL DENTINE - mainmass of dentine

SECONDARY DENTINE -slow increment to pulpal surface

{

REPARATIVE DENTINE -

response to caries/erosion

DEAD TRACT -wide, empty dentinal tubules

SCLEROTIC DENTINE -tubules narow, thenbecome filled with mineral

Diffuse

calcification

AGING PULP

PULP HORNobliterated

30 dentinedeposition

makes CHAMBER

SMALLERCELLS -Odontoblasts

FibroblastsMacrophagesMast cellsLeukocytes

Blood vesselsNervesLymphatics

Denticles

MATRIXCollagen I fibers

Collagen III fibers

ROOT CANALnarrows


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CEMENTOCYTES

PULP

AGING CEMENTUM

HYPERCEMENTOSIS -

excess deposition

CEMENTOCLASIA - erodedcementum

Interstitial AreaAGING PDLBone surface

more irregular

Bundles

less distinct

PDL Width

DENTINE

PULP

BONE

P

D

L


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AGING GINGIVA

Epithelialattachmentlooser,

displaced

DRY - Xerostomia -Dry mouth

INFLAMED

HyperkeratosisTOOTH

PERIODONTITIS

Periodontalligament

TOOTH

Alveolar bone

GINGIVA

EPITHELIAL ATTACHMENT-unstable, loosens &migrates down, & allowsbacteria into

CONNECTIVE TISSUE

resulting in chronicinfection &

inflammation &

systemic spread ofbacteria &

loss of teeth


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causes loss of alveolar ridges Mx & Mb

EDENTULOUS MANDIBLE

illustrates dependence of bone on use

loss of teeth

& loss of facial height

However, mandibularbody is less affectedby aging osteoporosis

than spine & longbones

BONE RESPONSE TO

TOOTH DISUSE Alveolar SPONGIOSA mostaffected, with extensiveloss of trabeculae


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LIPRED MARGINVERMILION BORDER

HAIRY SKINloseselasticity

MUSCLE

LABIAL MUCOSA

thick strat squam ep thins

LABIALGLANDmucous

Fordyces spots - sebaceousglands - more visible

Tongue papillae

smoother

Sub-lingual bloodvessels engorge- Caviar tongue

AGING TONGUE

Lingual gland


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CHEEK

SKIN

BUCCAL MUCOSAthick strat squam ep thins

BUCCAL GLANDmucous

MUSCLE

ADIPOSE TISSUE

Mucosa

loses elasticity

Fordyces spots - sebaceousglands - more visible & #

CHEEK

MINOR SALIVARY GLANDSMUSCLE

Smaller & fewer

Replaced by fibrous tissue

= STROMA:parenchymaMore lymphocytes present

Oncocytes develop

parenchyma= acini, tubules & ducts, i.e., epithelial components of gland


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AGING PAROTID GLAND

SEROUS ACINi

INTRA LOBULARDUCT

INTERCALATED DUCT

INTER LOBULAR DUCT

FAT

less control of

secretion quality

STROMA:parenchyma

ONCOCYTIC CONVERSION

As cuboidal epithelia and glands age, a few oftheir epithelial cells lose most of their normalorganelles and fill up with mitochondria.Mitochondria-rich cells are eosinophilic.

This event results in twoclasses of cell:

those that are functioning normallyand needmany mitochondria - gastric parietal cells, renalproximal-tubular cells, striated-duct cells, etc; &

non-functional mitochondria-stuffed cells in olderglands. These have acquired two names: theusual - oncocyte, and, as an exception, the archaicoxyphilcell in the parathyroids. & Hurthle cells

in thyroid

:


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ORAL TISSUE AGING: Interactions with

Altered & aging immunity

Microbial flora & disease

Changes of diet & food preference

deficiencies, malabsorptions

Altered dentition & prostheses

Aging nervous & endocrine systems

Trauma & repair

Mutated & moved DNA - tumorse.g., squamous carcinoma, adenocarcinoma, oncocytoma

Medicines & therapy


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ALVEOLAR BONE: Roles

The bone holds the tooth firmly in position tomasticate and, for the lower jaw, transmitsthe muscle-powered movements of the body

of the mandible. It also:

adapts the strengthand orientation ofattachment to varying load

helps to move the teethfor better occlusion

supplies vessels for the PDL & cementum

houses & protects developing permanentteethwhile suppporting primary teeth

organizes successive eruptionsof primary &secondary teeth

TOOTH TISSUES: Sources

DENTAL LAMINA

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

DENTAL ORGAN

ALVEOLAR BONE

TOOTH

PULP

DENTINE

ENAMEL

CEMENTUM

PDL

SUPPORTING

BONE

LAMINA DURA

Plate

Spongy bone


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Deciduous tooth

Gingiva

Cortical platedense bone

BODY ofMANDIBLE

ALVEOLAR BONE

in general

PDL

Permanenttooth

MANDIBULAR CENTRALINCISORS at 2 y

CORTICAL PLATE

ALVEOLAR BONEspecifically

ALVEOLAR BONE TERMS

SPONGIOSA

ALVEOLAR BONE isalso termed Lamina durafrom its X-ray densit, orcribriform bonefrom themany holes for vesselsto reach the PDL

Alveolar crest


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PDL Vessels DENTINE

Enter via cribriform(sieve) walls of thealveolus & at thebase

Lymphatic drainage

PULP

PDL

SUPPORTING

BONE

LAMINA DURA

Plate

Spongy bone

ALVEOLAR BONE

ALVEOLAR BONE TERMS


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PDL fibers (extrinsic)become imbedded innewly formed bone

BONE MATRIX

Fine collagen fibrils - intrinsic

MATRIXPROPORTIONS

collagen fibrils andglycoproteins &

proteoglycans 35%

Organic

mineral crystals 65%Inorganic

Imbedded PDL fibers -Sharpeys fibers

Osteocyte

MATRIX

OSTEOCYTE PROCESS

LACUNA (hole) for

CANALICULUS(tiny channel) for

Gap junction contactwith next osteocyte

OSTEOCYTE BODY


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TOOTH

BONE DEVELOPMENT

TOOTH BUD

DENTAL LAMINA from which DENTAL ORGANS (tooth germs) form

BRAIN

TONGUE

MAXILLARYBONE

MANDIBULARBONE

TONGUE

X

X

X

X

X

X

Mandibular bone

NASAL CONCHAE

FACIAL REINFORCEMENT

SEPTAL CARTILAGE

Maxillary bone

TOOTH BUD

HARD PALATE

X Skeletal muscle starting

XX


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TOOTH PRIMORDIUM/GERM

DENTAL LAMINA

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

DENTAL ORGAN

MESENCHYME

ALVEOLAR BONE

Mesenchyme

Condensations arewidely dispersedand separated tocommit a territoryto becoming bone

Continued division

& recruitment toosteoblast numbers

Vessels present

INTRAMEMBRANOUS OSTEOGENESIS


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OSTEOID

INTRAMEMBRANOUS OSTEOGENESIS

ACTIVE OSTEOBLASTS

OSTEOCLAST

TRABECULA

Mesenchyme

LESSACTIVECELLS

IM & EC OSTEOGENESIS

TRABECULAEthicken by division &recruitment of more

osteoblasts toincrease bone density

Mesenchyme later turnsinto marrow

Vessels : incorporatedfrom the start &remodel with the bone

OSTEOCLASTSactive from the start toremodel & reshape the

bone


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vessels

Osteoclast

Ca 2+

Active Osteoblasts

Bone canal

Resting cells

BONE CELLS

Periosteum

Osteocyte

Bone matrix = collagen fibrils +mineral crystals

Osteoclasts as a team eating out a resorption tunnel

Osteon/Haversian system withconcentric lamellar/layered bone

New bone -start of newosteon

Osteoblasts filling

in the tunnel

DENSE BONEREMODELING


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DENSE BONE

REMODELING*

Osteoclast

Ruffled border agitatingreleased enzymes & acid

Eaten-out hole is a

Howships lacuna

Un-mineralized OSTEOID betweenactive osteoblasts & calcified bone

DENSE BONE

REMODELING

Osteoclasts as a team eatingout a resorption tunnel

Osteoblasts filling

in the tunnel New bone

Sealing ringof tightattachmentto bone

JAW & TOOTH DEVELOPMENT early arch

BONE startingLINGUAL PLATE

BONE startingBUCCAL PLATE

SYMPHYSEALCARTILAGE

10 TOOTH GERM

20 SuccessionalTOOTH GERM

DENTAL LAMINA

WALLS OF BONYTROUGH OFDEVELOPINGMANDIBLE


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JAW & TOOTH DEVELOPMENT processes

BONE

10 TOOTH GERM

20 Successional TOOTH GERMon lingual side of 10

DENTAL LAMINA will grow back to formgerms for 3 permanent molars (5th e m)

PLANTING POTATOES

Bone creates thetrench; tooth budsare the spuds



BONE startingBUCCAL PLATEgrows up morethan lingual

SYMPHYSEAL CARTILAGEwill be replaced by bone

10 TOOTH GERM

20 Successional TOOTH GERMon lingualside of 10


Bony wall grows around& encloses 20 TOOTHGERM in a crypt

Interdental septumgrows across troughto separate teeth

Interradicular septumgrows between rootsof multirooted teeth


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TOOTH & MANDIBLE DEVELOPMENT

10 TOOTH

20 TOOTH GERM

MECKELSCARTILAGE

TONGUE

ALVEOLARBONE

DENTAL SAC

ALVEOLARNERVE

Oral ectoderm

Bone added tobase of alveolusfor tooth eruption

10 TOOTH

20 TOOTHGERM

MECKELSCARTILAGE

Alveolar crestgrows up

regresses & notused to formmandible

Bony plate grows upto enclose 2nd toothgerm in a CRYPT

Bone grows overalveolar nerve &vessels

Alveolus becomesdistinct from BODY

DENTAL SAC contributesalso to alveolar bone

MANDIBLE DEVELOPMENT

Remodeling will bring erupting1o tooth over developing 2o


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10 TOOTH

20 TOOTH GERM

MECKELS

CARTILAGE

TONGUE

ALVEOLAR

BONE

DENTAL SAC

ALVEOLAR

NERVE

Higher alveolar bone- i.e. deeper socket

Denser alveolar bone & morebody-alveolus distinction

Meckels cartilage gone

TOOTH & MANDIBLE DEVELOPMENT - Next

Remodeling brings erupting 1o

tooth over developing 2o

BUNDLE BONE

Imbedded ends ofPDL fibers createBUNDLE BONE

DENTINE

PULP

Imbedded PDL fibersare Sharpeys fibers


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TOOTH MOVEMENT

Osteoblastslaying downbundle bone

Tooth drifts mesially

by combined actions

of osteoclasts &osteoblasts movingbone, taking toothwith it

Osteoclastsresorbing bone

Plus PDLreorganization

Osteoclasts

resorbing bone

PDL fibersincorporated in boneas Sharpeys fibers

FUNCTIONAL ERUPTION& TOOTH MOVEMENT

Osteoblasts

laying downbundle bone

Cellular cementum added to apexCompensates for occlusal wear?

Occlusal wear

Bonyinterdentalseptum

Basil


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TOOTH MOVEMENTS

DRIFTING e.g., mesially, laterally

AXIAL - in long axis of the tooth

Basil

Occurring in eruption & use

ROTATORY

TILTING

By root growth &bone remodelling

By bone remodelling &PDL reorganization

Combinations of these fourmovements frequently occur

TOOTH MOVEMENT 2

Basil

Earlier boneposition

TILTINGTooth tilts by combinedactions of both osteoclasts& osteoblasts on bone of

each sideof socket


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TOOTH MOVEMENT

Tooth drifts mesially bycombined actions ofosteoclasts & osteoblastsmoving bone, taking toothwith it

Basil


10/Deciduous tooth Close to EXFOLIATIONof Deciduous/10 Tooth

Bone trabeculaeadded by layers atbase of alveolus

Odontoclasts haveresorbed most ofdeciduous root

Bone remodellling

has brought 20 toothunder 10

20 tooth would beLARGER than shown

20 tooth


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STARTING EXFOLIATION of DECIDUOUS MOLAR I

ALVEOLARBONE

DENTINE

ENAMEL

Permanent Tooth underdeciduous molar, &between its roots

Inter-radicular septum of bone alsohouses 2nd tooth germ & is its crypt

Root resorptionby osteoclasts

PDL

PULP

EXFOLIATION of DECIDUOUS MOLAR III

Erosion of bone and the deciduous root is not steady & continuous,but may cease briefly, when some repair of eroded cementum &dentine can occur (by cementum).

Bone remodelling also goes on, and the alveolus andcrypt are changing all the time - repeated all along the jaw

DENTINE

ENAMEL


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2 Much surfacearea for attack byosteoclasts

1 Struts are thin tostart with ~ weak

3 Gap in a strut/trabecula cut right through isusually too wide to be bridged by any new bone

SPONGY BONE at more risk than dense bone

Reduction in # &size of principal

fibers

Periodontal reactions to disuseLoss ofalveolar bone

Bundledefinitionlost

PDLnarrower allaround

DENTINE

PULP

BONE

CEMENTUMthickensP

D

LCEMENTUMlosesSharpeysfibers

Mild bonedepositionon wall


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BONE RESPONSE TO

TOOTH DISUSE

SPONGIOSAmost affected,with extensiveloss oftrabeculae

ALVEOLAR BONE: Roles

The bone holds the tooth firmly in position tomasticate and, for the lower jaw, transmitsthe muscle-powered movements of the bodyof the mandible. It also:



supplies vessels for the PDL & cementum

houses & protects developing permanentteethwhile suppporting primary teeth

organizes successive eruptionsof primary &secondary teeth


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TOOTH TISSUES: CEMENTUM

ALVEOLAR BONE

WABeresford

PULP

DENTINE

ENAMEL

CEMENTUM

PERIODONTAL

LIGAMENT/ PDL

GINGIVA

Blade Shaft Grip

ENAMELCEMENTUMDENTINE

TOOTH DESIGN: Spear me


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ENAMEL CEMENTUMDENTINE

Shaft is hollow forPULP

Hand represented byPERIODONTAL LIGAMENT& ALVEOLAR BONE

Refinements

Closer to true proportions

CEMENTUM: Role

Cementum is the hard covering of theroot that can:

fuseto dentine, but

be aliveand

grow outwardsto trap the periodontal-ligament fibers, and thus

attachthe tooth to the alveolar bone.

It is itself a kind of bone, but is lesssusceptible to erosion


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vessels

Osteoclast

Ca2+

Active Osteoblasts

Bone canal

Resting cells

REMINDER -BONE CELLS

Periosteum

Osteocyte

Bone matrix = collagen fibrils +

mineral crystals

CEMENTUM-BONE DIFFERENCES

NO VESSELS OR CANALS

WITHIN CEMENTUM

FORMING CELLS ARECEMENTOBLASTS

NO TRABECULAENO MARROW

IMBEDDED CELLS ARECEMENTOCYTES

COLLAGEN FIBERSPERPENDICULAR TOSURFACE

vessels

Osteoclast

Ca2+

Active Osteoblasts

Bone canal

Resting cells

Periosteum

Osteocyte


mineral crystals

NO PERIOSTEUM

ACELLULAR CEMENTUMEXISTS

ALMOST NO REMODELING


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BONE-CEMENTUM SIMILARITIES

MATRIX MATERIALS

EROSION BYOSTEOCLASTS(cementoclasts)

APPOSITIONAL GROWTHFROM SURFACE

LACUNAE WITHCANALICULI FOR CELLS &CELL PROCESSES

INCREMENTAL GROWTHLINES IN MATRIX

SIMILAR APPEARANCE INSTAINED & GROUNDSECTIONS

vessels

Bone canal

Periosteum


mineral crystals

P

ULPAL

ORIENTATION: Terms

CUSPAL/OCCLUSAL

APICAL

CERVICAL {

CORONAL

RADICULAR

Enamel

Cementum


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PULP

DENTINE

CEMENTUM

CEMENTUM: Position

ENAMEL

CROWN

Cervix

ROOT

}

}Cementum is on the root, but can extend slightlyonto enamel. Cementum also can be exposed tothe oral cavity, if the gingiva recedes too far

CEMENTUM: types & width

The left of this Fig is

misleading in

suggesting that allcementum iscellular.

The cervical half isthin and acellular-no cementocytes

P

ULPAL

APICAL

}Cementum

10 mthick

700 mthick


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Multi-rooted teeth usually

have particularly thick &cellular cementumbetween the roots in aninter-radicularposition

INTER-RADICULAR CEMENTUM

CEMENTUM: Boundaries

Cemento-enamel junction CEJ

Dentino-cemental junction DCJ

Ligamento-cemental junction

APICAL FORAMEN


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E E

D D

E

D

CEMENTUM: CEJ VARIATIONS

OVERLAP C/Emost frequent

GAPdentine exposed

BUTT JOINTend-to-end

CEMENTUM

E

D

E

D

Reactivated cementoblastslay down cementoid

E

D

E

D

GROWTH OF CEMENTUM = PDL anchoring

Cementoid becomesanother layer of cementum.Cells make more cementoid

PDL

fibers

PDL fibers becomeimbedded in newlyformed cementum -

Sharpeys fibers


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Further down the rootcementoblasts proliferatedso that one cell canbecome imbedded as acementocyte, whileanother remains on thesurface as a cementoblastD

GROWTH OF CEMENTUM III

D

Further down the rootcementoblasts proliferate

PDL fibers omitted.

PDL fibers (extrinsic)become imbedded innewly formed cementum-

CEMENTUM MATRIX

Fine collagen fibrils - intrinsic

MATRIX

PROPORTIONS


proteoglycans 35%Organic


Imbedded PDL fibers -

Sharpeys fibers -notspecific to cementum


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REDUCEDDENTALEPITHELIUM

HERTWIGSROOTSHEATH

DENTINE

Epithelial diaphragm

ROOT FORMATION

Odontoblast recruitment site

Root sheathbreaks up, allowingsac mesenchymalcells to contactroot dentine

DENTINE

PULP

Odontoblast recruitment site by root sheath: pulp signaling

Root sheath breaks up & lifts,allowing sac mesenchymal cellsto contact root dentine

CEMENTOGENESIS START

Dentine &/or Epithelial root

sheath induces mesenchymalcells to become cementoblasts


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Dentine formed beforecementum

& cervical before apical

Directions of

cementalgrowth -outwards &apicalwards

SEQUENCES

Osteoclasts

resorbing bone



Osteoblasts



Occlusal wear

Bonyinterdentalseptum

Basil


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PULP

CEMENTUM: Defects

CORONAL CEMENTUMspurs, etc, on enamel

HYPERCEMENTOSIS -

excess deposition

CEMENTOCLASIA - erodedcementum (occurs normally indecidual-tooth shedding)

CEMENTICLESIN PDL

CEMENTUM: Repair

After cementoclasia,cementoblasts may fillin the defect with newcementum.This cycle can be repeated,and also occurs a littleduring shedding & afterroot fracture

PU

LP

P

ULP


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Erosion of bone and the deciduous root is not steady &

continuous, but may cease briefly, when some repair oferoded cementum & dentine can occur (by cementum).

DENTINE

ENAMEL

P

ULP

CEMENTICLES

Hard mineralized bodies found inthe periodontal ligament orpartially imbedded in cementum


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DENTAL PAIN

Dental pain enters consciousness (HURTS) &becomes a major aspect of dentistry

What is the innervation of the tooth & periodontium?

How are these nerve fibers and endings relatedto dental pain?

How do the stimuli - heat, inflammatorymediators, etc - activate the nerve fibers?

What are the central pathways, structures, &interactions bringing pain to conciousness?

WABeresford

SENSITIVE?

DENTAL SENSITIVITIES

Dentine

Enamel

Cementum

Pulp

PDL


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PULP INNERVATION

Nerves: sensory (V) to

PULP

ODONTOBLASTS

DENTINAL TUBULES

Blood vessels

Nerves:

autonomic

1

2 3

1

2

3

Sub-odontoblastic plexus

in cell-poor zone of Weil

EXTENT of TOOTH INNERVATION

Fibers grow in during development & some transfer to20 tooth, so 20s have more nerves fibers than 10s

Sub-odontoblasticplexus of Raschkow

Hundreds of nerve fibers per tooth

Most fibers branch


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FIBER CALIBER & MODALITY

Hundreds of nerve fibersper tooth

10 % myelinated A fibers

80 % unmyelinated C fibers

No specialized receptors

< % A fibers

NOCICEPTION - pain - sensorymodality for pulp & dentine

1/2

FIBER FUNCTIONS

Autonomic roles

NOCICEPTION - pain - the sensorymodality for pulp & dentine

< % A fibers1/2

But what do these do?

Any trophic effects on

pulp from sensory fibers?

Hundreds of nerve fibersper tooth


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V

Sup CervicalGanglion

Branch of external

carotid A

Sympathetic fibers

PNS: AUTONOMICS

Pulp vesselOther targets?

Superior alveolar nerves

Inferior alveolar nerves

Trigeminal ganglion

Spinal nucleus of V

CNS

Convergencefrom several teeth onto one CNS neuron

PNS:CNS Sensory relations


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POOR LOCALIZATION

DULL ACHE

ACUTE, SHARP

Convergence

PAIN QUALITY

myelinated A fibers

unmyelinated C fibers

Inferior alveolar nerves

Trigeminal ganglion

Spinal nucleus of V

CNS

Sympathetic

PERIODONTAL LIGAMENT INNERVATION

Free ending

Ruffini receptorsMechanoreceptors for stretch

V Ganglion

Modalities: PROPRIOCEPTION & pain

Mesencephalicnucleus of V

Sup CervicalGanglion

CNS


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Reticular formation

Thalamic VPM

CNS: Dental pain pathways

Periaqueductalgrey (PAG)

SENSORY CORTEXParietal lobe

TRIGEMINAL NERVE

Mesencephalic N of V

Spinal V tractSensory V Nucleus

CNS

Spinal N V

Reticular formation

Thalamic VPM

CNS: Dental pain pathways

SENSORY CORTEX

TRIGEMINAL NERVE

Mesencephalic N

Spinal V tractSensory V Nucleus

Spinal N V Periaqueductal grey(PAG) can inhibitascending painsignals by usingendorphins, enkephalins


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Reticular formation sends signals everywhere

Sensory relays - Inhibitionof incoming & ascendingsensory signals

RETICULAR FORMATION: Roles

Motor nuclei - reflexes

Cortex - arousal

Hypothalamus -autonomic responses

Limbic system -emotions

NERVE-FIBER:STIMULI RELATIONS I

ODONTOBLASTS

Sub-odontoblastic plexus

2 3

Worn dentine brings stimulinearer to pulp

HeatColdPressure

Chemicals?

Enamel

Axons in tubules

Axons around

odondoblast bodies

ODONTOBLAST assensory transducer ?

Pulp

Direct pulpstimuli


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NERVE-FIBER:STIMULI RELATIONS II

ODONTOBLASTS

Pulp fibers sensitizedby factors releasedbecause of inflammation or previous activity

2 3

Worn dentine brings stimulinearer to pulp

HeatColdPressureChemicals

Enamel

Axons in tubules

Axons around

odondoblast bodies

Pulp

NERVE-FIBER:STIMULI RELATIONS III

HYDRODYNAMIC hypothesis of sensitivity

Axons aroundodondoblast bodies

ODONTOBLASTS

HeatColdPressure

Enamel

Axons in tubules

Stimuli move fluidback & forth in thetubule stimulatingtubule axons &/orodontoblasts

Dentine


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NERVE-FIBER:STIMULI RELATIONS IV

ODONTOBLASTS

HeatColdPressure

Enamel

Dentine


Axons aroundodondoblast bodies

Stimuli move fluidback & forth in thetubule

with distortionof the odontoblast possibly causing it to releaseATP, and thus chemically exciting the axon - Alavi AM et al.Immunohistochemical evidence for ATP receptors in human pulp. J Dent Res2001;80:476-483

ODONTOBLAST assensory transducer ?


Stimuli move fluid

back & forth in thetubule

with distortionof the odontoblast possibly causing it torelease ATP, and thus chemically exciting the axon - AlaviAM et al. Immunohistochemical evidence for ATP receptors in humanpulp. J Dent Res2001;80:476-483


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DENTAL PAIN: Unknowns

Stimulation mechanisms in pulp - normal & diseased

Reticular formation - what happens centrally

Patterns of firing - relation to perceptions

First Anatomy Journal about 1860; first Pain journal 1973

Allowed to work on animals only if pain is preventedor minimised

Animal cannot tell of pain; humans reluctant to let you

hurt them or do invasive investigations, e.g., nerverecordings

Many small nerve fibers used for other purposes,e.g., autonomic

No specialized pain endings? Defining pain stimuli?

Complex chemistry with tissue injury

Poorly understood dynamic interactions between

CNS & PNS - Pain is in the mind & usually in the body(CNS-PNS interactions: compare sexual arousal)

PAIN: Difficult to study


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TOOTH TISSUES: DENTINE

ALVEOLAR BONE

WABeresford

PULP

DENTINE

ENAMEL

CEMENTUM

PERIODONTAL

LIGAMENT/ PDL

GINGIVA

Blade Shaft Grip




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Blade Shaft Grip





Hand represented by

PERIODONTAL LIGAMENT& ALVEOLAR BONE

Refinements


DENTINE: Role

Dentine is the major tissue of the tooth,acting as the living, hard, strong &resilient core, to which specializedtissues attach


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Dentine is themajor tissue ofthe tooth, actingas the living,hard, strong &resilient core, towhich specializedtissues attach

DENTINE: Correlates

MATRIX of collagen fibrils andglycoproteins & proteoglycans -

STRENGTH & RESILIENCE

mineral crystals - HARDNESS

ODONTOBLASTS & their processes -

LIVING

PULP

DENTINE

CEMENTUM

DENTINE: Position

ENAMEL

CROWN

Cervix

ROOT

}}

CROWN/CORONAL

DENTINE

ROOT/RADICULAR

DENTINEversus


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DENTINE: Boundaries

Dentino-enamel junction DEJ

Dentino-cemental junction DCJ

Pulp surface

APICAL FORAMEN

Orally exposed - pathological

Odontoblastsin an epithelial-like layer

DENTINE: Composition

MATRIX of collagen fibrils, mineralcrystals, and glycoproteins & proteoglycans

Penetrated by TUBULES containing long thinprocesses of cells - ODONTOBLASTS -whose bodies lie outside and against the

pulpal surface of the dentine


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5

DENTINE: Composition

MATRIXPROPORTIONS


proteoglycans 30%Organic


MATRIX of collagen fibrils, mineralcrystals, and glycoproteins & proteoglycans

TUBULE

DENTINE: Composition II

MATRIX subdivided into

TUBULES 1-3 m wide

Peritubular dentine Neumanns sheath

Inter-tubular dentine


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DENTINE: Reality

Matrix-tubule ratios vary

Tubules curve

Processes split

Processes extendinto enamel rare

ENAMEL

SPINDLES

DENTINE: Growth

Odontoblasts

Enamel PREDENTINE

DENTINE

Direction of growth -

pulpward from DEJ

Matrix color as seen with H&E:dense collagen gives a red color, butpredentine is paler. Matrix fibrils areunseen.

Enamel is

removed by the

decalcification

needed for wax

sections


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TOOTH GERM: Odontoblast recruitment

DENTALPAPILLAbecoming

pulp

outermost papillacells have becomeOdontoblasts

Recruitment site

Ingrowing pulp vessels

TOOTH GERM:Dentinogenesis

DENTALPAPILLAbecomingpulp

cusp Dentineformed by

OdontoblastsRecruitment site

for odontoblasts


Dentine is formed first as predentine -organic phase precede mineralization


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8

PULPA

L

ORIENTATION: Terms

CUSPAL/OCCLUSAL

APICAL

CERVICAL {

CORONAL

RADICULAR

Enamel

Cementum

Dentine first formed at CEJ

Coronal dentine formedbefore root dentine, AND

cuspal before cervical, &cervical before apical

Pulpal-surface dentine is

formed last

Odontoblast

trajectoriesduring growth

SEQUENCES


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Dentine first formed at CEJ

Odontoblasttrajectoriesduring growth

INCREMENTAL GROWTH

Contour lines of Owen reflectvarying physiologicalcircumstances during growthneonatal line is most prominent

This view tries to show

something of the appearance of

the ground section of tooth. Tosee detail, the glare needs to betaken out by closing the irisdiaphragm (the lever on thecondenser) as required

P

ULP

MATURE DENTINE: Varieties

MANTLE DENTINE justbelow DEJ coarser fibrils

CIRCUMPULPAL DENTINE -main mass of dentine

TERTIARY DENTINE* - slow

increment to pulpal surface

{

REPARATIVE DENTINE* -response to caries/erosion

* * Response relies on the pulp and theodontoblasts staying alive & active


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PUL

P

REPARATIVE DENTINE 2

REPARATIVE DENTINEin response to attrition/wear ofthe cusp

P

ULP

MATURE DENTINE: Defects

CARIOUS DENTINEwide bacteria filled tubules

INTERGLOBULAR AREASlack mineral

DEAD TRACT -wide, empty dentinal tubuleseasily colonized by bacteria

TOMES GRANULAR LAYERholes in root dentine near DCJ

SCLEROTIC DENTINE -tubules filled with mineral


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MATURE DENTINE: Usual Defects

PULP

INTERGLOBULAR AREASlack mineral

TOMES GRANULAR LAYERholes in root dentine near DCJ

SCLEROTIC DENTINE -tubules filled with mineral

normal development

normal aging

INTERGLOBULAR AREAS lackmineral & appear as black batswings in the ground section. Theyrepresent incomplete expansion ofthe spherical (globular)mineralising foci in the predentine

P

ULP

Interglobular areas are close to the CEJ,but may be seen in radicular dentine


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PULP

DENTINTICLES/ PULP STONES

Hard mineralized bodies found inthe pulp or the dentine

TWO TYPES:

1 TRUE - constructed of dentine

by odontoblasts & showingdentinal tubules

2 FALSE - mineralized connective

tissue, etc, (not made of dentine)

Both may show layering/lamellar patterns from

incremental growth

P

ULP

DENTINTICLES/ PULP STONES:further classification by place

Hard mineralized bodies found in the pulp orthe dentine

THREE SUBTYPES:

1 FREE - in the pulp

2 IMBEDDED - enclosed in thedentine as this has slowly grown

inwards

3 ATTACHED - partly imbedded


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TOOTH TISSUES: ENAMEL

ALVEOLAR BONE

WABeresford

PULP

DENTINE

ENAMEL

CEMENTUM

PERIODONTAL

LIGAMENT/ PDL

GINGIVA

Blade Shaft Grip




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Refinements


ENAMEL: Role

Enamel is the dead, very hard,but brittle cutting/grindingoral covering of the tooth


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PULP

DENTINE

CEMENTUM

ENAMEL: Position

ENAMEL

CROWN

Cervix

ROOT

}

}

ENAMEL: Boundaries

Dentino-enamel junction DEJ

Orally exposed surface with acquiredPELLICLE

Cemento-enamel junction - CEJ


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E E

D D

E

D

CEMENTUM: CEJ VARIATIONS

OVERLAP C/Emost frequent

GAPdentine exposed

BUTT JOINTend-to-end

CEMENTUM

60% 10%30%

ORIENTATION: Terms

CUSPAL/OCCLUSAL

APICAL

CERVICAL

CORONAL

P

ULPAL

{

Enamel


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5

ENAMEL: Nature

Enamel is the dead, very hard, but brittle cutting/grinding oral covering of the tooth

This degree of hardness can be achieved by thedense packing of curved rods/prismscomposedalmost entirely of densely arranged spikey mineralcrystals, with a keying together of the prisms

R

OD

RO

D

Mineral is hydroxyapatite, withCa2+, OH-, PO4

--, etc, ions

Cross-section of rods

Hardness from material & interlocking devices

ENAMEL

DEJ

PRISMS/RODS

Enamel is 96% large mineralcrystals arranged as long wavyinterlocked rods/ prisms

Demarcation between prisms

is called the ROD SHEATH -more organic, slightly lessmineral

Enamel is:96% mineral,3% water,1% organic material

First enamel is NON-PRISMATIC

Last enamel is NON-PRISMATIC


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Enamel

Enamel first formed at DEJ

Cusp enamel formedbefore cervical

Ameloblasttrajectoryduring growth

SEQUENCES

Enamel growsoutwardsfromthe DEJ

One ameloblastmakes one prism/rod

DEJ Story I

Mesenchyme

Starts as basal

lamina betweeninner epithelial cells

& dental-papilla cells


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DEJ Story II & III

Continues as basal laminabetween inner epithelialcells & odontoblasts (2nd)

Goes on to be a basal lamina

between inner epithelial cells& dentine (third step)

cusp enamelformed by

ameloblasts

DEJ Story IV

Dentine instructs inner epithelialcells to become ameloblasts -through an intact, then through adisintegrating basal lamina?

Ameloblasts lay downenamel matrix on thedentine to create the DEJ


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DEJ Story V & VI

DEJ is actually a little irregular,as a serrated or scalloped lineseen in ground sections

ENAMELSPINDLE

Odontoblast process stuck intoenamel matrix while it was soft,

thus crossing the DEJ

E

D

Cross-section of rods

ENAMEL: Problems

PROBLEMS:

the precise wear-resistant architecture needsa prior cell-oriented organic precursor

a maturation phasehas to replace the

organic with inorganic mineral

the direction of growth outward from the DEJleaves the formative cells on the surfacewhere they cannot survive- no later repairpossible

deleterious agents can substitutefor ions inthe crystal lattice, e.g., Pb, Sr90, Fl, &

tetracycline can bindto the mineral

ROD R

OD


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9

Ameloblast

Tomes process

ROD

ENAMEL FORMATION - AMELOGENESIS

COMPARTMENT FORSECRETORY RELEASE

Organic first deposits,e.g., amelogenin, + 30%mineral

organic materials digested;replaced by mineral to 96% -

maturation

DEJ DEJ

Ameloblast

Tomes process

ROD

AMELOBLASTS TOMES PROCESS

COMPARTMENT FORSECRETORY RELEASE

Releases vesicles ofamelogenin, etc

later releases enzymes to digestorganic matrix (replaced bymineral to 96%- maturation)

transports ions into matrix

Process defined by terminalweb of actin etc stretchingbetween junctional complexesfastening ameloblasts together


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Ameloblast

ROD

AMELOBLASTS VASCULAR RELATIONS

Outer dental epithelium

BASAL LAMINA

CAPILLARY

Collapse of stellatereticulum lets vesselsapproach closer to the

highly active ameloblasts

Stratum intermedium

TOOTH GERM

DENTAL LAMINAupper degenerateslower forms 2nd bud

Outer dental epitheliumcollapsing down

Stellate reticulumreducing over cusp

Cervical loopdefines extent ofcrown to crownbase; then itstarts the rootsheath


DENTAL SACquiescent

Knot cells signalto papilla outermost papilla

cells have become

Odontoblasts

Recruitment site



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TOOTH GERM:

result & next steps

Stellate reticulummoving apically

cusp Dentineformed byOdontoblasts

Dentine is formed first as predentine.

It will signal to inner dental

epithelial cells to become ameloblasts

TOOTH GERM: all crown-forming elements present

Ameloblasts

Stellate reticulum

DENTAL SACstill quiescent

cusp enamelformed byameloblasts

Capillaries now close to

synthesizing ameloblasts

Dentine

Enamel is always

less extensive than

dentine


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DENTALPAPILLAbecomes pulpprocessproceedsdowns

Stellate reticulumfollows Cervical

loop down thenstops: Crown

defined

Second reductioninenamel epithelium:

retired ameloblasts &compacted outerepithelium, stellate-reticulum cells &stratum intermedium

CHANGES IN DENTAL/ENAMEL ORGAN III

Ameloblasts

will finish fullthickness of

cusp enamel& reduce inheight

Dentine widens

Cervical loop:

Odontoblast

recruitment

site

Where Stellatereticulumstopped, thecervical loop

continued togrow down, butas

ENAMEL


HERTWIGSROOT SHEATH& its

DENTINE

PULP


CROWN

CROWN COMPLETED


ROOT


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REDUCEDDENTAL

EPITHELIUM will

fuse with gingiva

ROOT FORMATION: Coronal consequences

GINGIVALEPITHELIUM

As root

lengthenscrown ispushed up -Pre-EMERGENCE

HERTWIGSROOTSHEATHgrows tolengthen root

Connective

tissue brokendown

REDUCEDDENTAL

EPITHELIUM

protects

enamel

ENAMEL

REDUCED DENTAL

EPITHELIUM

TOOTH EMERGENCE

GINGIVALEPITHELIUM

still fusing with

CUTICLEwill wear away


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ORGANIC ENAMEL SURFACE


PELLICLE ofglycoproteins etc isacquiredlater from saliva

PLAQUEthe biofilmof many kindsof bacteria then attachesto the pellicle

INCREMENTAL GROWTH

Contour lines of Retziusreflect varying physiologicalcircumstances during growthneonatal lineis most prominent

As ameloblasts make prisms, diurnalfluctuations in their physiology

produce faint striationsacross therods

Unless erased by wear, perikymataare a mild ripple effect seen on thesurface of enamel from the slightly

differing qualities of enamelremember the flat-wet-sand, low-tide effect


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ENAMEL IN HISTOLOGY

Being 96% mineral, enamel makesteeth too hard to cut for imbedded& stained sections

Demineralization with acid or achelator, for H&E sections destroysmature enamel, creating a space

Demineralization for H&E leavessome of the immature enamel ofearly formation, particularly in thelast-formed cervical region

Ground sections, unstained, preservemature enamel, but may introduce cracks

immatureENAMELmatrix remains


DENTINE

PULP

AFTER DEMINERALIZATION

space wherematureENAMEL hasbeen lost

most recentlyformed, henceimmature


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TUFT

GNARLEDENAMEL

ENAMEL: Special features

LAMELLA

FISSURE/PIT

SPINDLE

ENAMEL: Special features FISSURE/PITAmeloblastswere cramped

while makingenamel

ENAMELSPINDLE

Odontoblastprocess stuck intoenamel matrix

while it was soft


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LAMELLA

TUFT

GNARLED

ENAMEL

ENAMEL: Special features Mostly visualeffect from varied

rod directions

Mostlyvisualeffectfromunusually

varied roddirections

Vertical cracks filledwith mineralizedorganic material

Lamellae are seen incoronal cross-sections

PULP

ENAMEL: minor defect

CORONAL CEMENTUMspurs, etc, on enamel

Reduced enamel epitheliumhad gaps that allowedmesenchymal cells in tobecome cementoblasts


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MATURE ENAMEL: Severe Defects

PULP

ATTRITION/ WEAR

CARIES/DECAY

Any loss is severe since thereare no ameloblasts to replace it


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PULP

DENTINECEMENTUM

PERIODONTAL

LIGAMENT/ PDLALVEOLAR BONE

WABeresford

ROOT FORMATION & ERUPTION

What has to be controlled

Shedding of teeth

Number of roots

Shapes of root

Times of eruption

Four tissues in sequence

Organize surroundings

Fasten tooth to surroundings

Successional teeth

Length of root

Pulp Dentine Cementum Ligament

& coordinatede.g., cementum with PDLwith bone


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TOOTH TISSUES: Cell Sources

DENTAL LAMINA

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

DENTAL ORGAN

ALVEOLAR BONE

PULP

DENTINE

ENAMEL

CEMENTUM

PDL

A BONE

TOOTH

Crest

Ameloblasts

Odontoblasts

CT cells

Cementoblasts

Fibroblasts

Osteoblasts & clasts

Deposition of alveolar bone?

MECHANISMS OF ERUPTION

Formation of the root

Construction & Reorganization of PDL

Remodelling of bone overall

FURTHER INFLUENCES from: tooth/teeth in occlusion; muscle actions


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TOOTH GERM:

next stepsDENTAL LAMINAupper part degenerateslower forms 2nd bud


approaches inner

Stellate reticulumreduces over cusp

Inner & outer dental epitheliajoin to form cervical loop

Stratum intermedium

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

Knot cellssignal topapilla

First reductioninenamel epithelium:active ameloblasts &

compacted outerepithelium, stellate-reticulum cells &

stratum intermedium

LATE CROWN FORMATIONcusp enamelformed byameloblasts

Dentine

Cervical loop:inner & outerepithelium

DENTALPAPILLA

become pulp

remainingStellate reticulum



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DENTALPAPILLAbecome pulpprocessproceedsdowns

Stellate reticulumfollows Cervical

loop down thenstops: Crown

defined

END OF CROWN

FORMATION

Ameloblasts

will finish fullthickness of

cusp enamel& reduce inheight

Dentine widens

Cervical loop:

Odontoblast

recruitment

site

Where Stellatereticulumstopped, thecervical loop

continued togrow down, butas

ENAMEL


HERTWIGSROOT SHEATH& its

DENTINE

PULP


CROWN

ROOT FORMATION


ROOT


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ENAMEL

REDUCED

DENTALEPITHELIUM

HERTWIGS

ROOTSHEATHgrows tolengthen root

DENTINE

PULP


FURTHER ROOT FORMATION



Other sacmesenchymal

cells constructPDL & somealveolar bone

Fibroblasts

ROOT SHEATH & ITSDIAPHRAGM widens& constricts to createtwo diaphragms todefine two roots


ROOT FORMATION: Multirooted

ENAMEL

DENTINE

PULP

CROWN

ROOT

ROOT SHEATH

Cross-sections


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Thus, one dental organcan produce two orthree roots

ROOT FORMATION: Multirooted

Epithelial diaphragm ROOT SHEATH

ENAMEL

DENTINE

PULP

CROWN

ROOT

Similarly, one dentalorgan can producetwo or more cusps,

using multipleenamel knots

ENAMEL

REDUCED DENTALEPITHELIUM

DENTINE

PULP

Odontoblast recruitment site by root sheath: pulp signaling

Root sheath breaks up & lifts,allowing sac mesenchymal cellsto contact root dentine

REITERATIVE SIGNALING V

Dentine &/or Epithelial rootsheath induces mesenchymal

cells to becomecementoblasts


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7

JAW & TOOTH DEVELOPMENT early arch


BONE startingBUCCAL PLATE

SYMPHYSEALCARTILAGE

10 TOOTH GERM

20 SuccessionalTOOTH GERM

DENTAL LAMINA

WALLS OF BONYTROUGH OF

DEVELOPINGMANDIBLE



BONE startingBUCCAL PLATEgrows up morethan lingual

SYMPHYSEAL CARTILAGEwill be replaced by bone

10 TOOTH GERM

20 Successional TOOTH GERMon lingualside of 10


Bony wall grows around& encloses 20 TOOTHGERM in a crypt

Interdental septum

grows across troughto separate teeth

Interradicular septum

grows between rootsof multirooted teeth


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TOOTH & MANDIBLE DEVELOPMENT

10 TOOTH

20 TOOTH GERM

MECKELSCARTILAGE

TONGUE

ALVEOLARBONE

DENTAL SAC

ALVEOLARNERVE

Oral ectoderm

Bone added tobase of alveolusfor tooth eruption

10 TOOTH

20 TOOTHGERM

MECKELSCARTILAGE

Alveolar crestgrows up

regresses & notused to formmandible

Bony plate grows upto enclose 2nd toothgerm in a CRYPT

Bone grows overalveolar nerve &vessels

Alveolus becomesdistinct from BODY

DENTAL SAC contributesalso to alveolar bone

MANDIBLE DEVELOPMENT

Remodeling will bring erupting1o tooth over developing 2o


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10 TOOTH

20 TOOTH GERM

MECKELS

CARTILAGE

TONGUE

ALVEOLAR

BONE

DENTAL SAC

ALVEOLAR

NERVE

Reduced enamel epitheliumfused with gingiva

Higher alveolar bone- i.e. deeper socket

Longer root withcementum forming

More advanced 2nd tooth

Denser alveolar bone & morebody-alveolus distinction

Meckels cartilage gone

TOOTH & MANDIBLE DEVELOPMENT - Next

Remodeling brings erupting 1o

tooth over developing 2o

ENAMEL

REDUCED DENTAL

EPITHELIUM

TOOTH EMERGENCE

GINGIVALEPITHELIUM

still fusing with



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ORGANIC ENAMEL SURFACES


PELLICLE ofglycoproteins etc isacquiredlater from saliva

PLAQUEthe biofilmof many kinds

of bacteria then attachesto the pellicle, & latermineralizes - tartar

DENTINE

ENAMEL

BONE

GINGIVA


ROOT SHEATH

CEMENTUMPDL

PULP

Cementum starting assheath breaks down

LATE ERUPTING TOOTH

Rests of Mallassezremnants of Root sheath


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ROOT SHEATH

LATE ERUPTING TOOTH

DENTINE

ENAMEL

BONE

GINGIVA

CEMENTUMPDL

PULP



Deciduous tooth

Gingiva


BODY ofMANDIBLE

ALVEOLAR BONE

PDL

Permanenttooth

MANDIBULAR CENTRALINCISORS at 2 y


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Gubernacular cord offibrous tissueGubernacular cord

runs through a canalleft in the bony crypt,where the dentallamina extendeddown to establish thegerm for the 2ndtooth

Permanenttooth

Go Gubba

Deciduous tooth


Permanenttooth

MANDIBULAR CENTRALINCISORS at 2 y - Bone

Spongy/ cancellous bone

Resorption of bone& deciduous rootwill start here


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10/Deciduous tooth

PDL attachment issurprising persistent

Close to EXFOLIATIONof Deciduous/10 Tooth

Bone trabeculaeadded by layers atbase of alveolus

Odontoclasts haveresorbed most ofdeciduous root

Pulp is leftalive

Bone remodelllinghas brought 20 tooth

under 10

20 tooth would beLARGER than shown

20 tooth

DENTINE

ENAMEL

BONE

GINGIVA Oral Ectoderm


ROOT SHEATH Dental organ

CEMENTUM Dental sacPDL

PULP

PDL Dental sac

LATE ERUPTING TOOTH: Origins


BONE Arch Mesenchyme & Dental sac


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WHY STILL ERUPTING

DENTINE

ENAMEL

BONEPDL

PULP

APEX INCOMPLETE

Pulp chamber wide(no apical taper)

Cementum not to apex

& Bone forming in base of alveolus

Epithelial diaphragm present

Immature connective tissue

STARTING EXFOLIATION of DECIDUOUS MOLAR I

ALVEOLARBONE

DENTINE

ENAMEL

Permanent Tooth under deciduousmolar, & between its roots

Inter-radicular septum of bone alsohouses 2nd tooth germ & is its crypt

Root resorptionby osteoclasts

PDL

PULP


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EXFOLIATION of DECIDUOUS MOLAR II

ALVEOLARBONE

DENTINE

ENAMEL

Focal erosion along this lineleaves a ROOT FRAGMENTwhich may be retained

Resorbed dentine partlyrepaired by new cementum

Crypt boneeroded here

PDL

PDL is disrupted in regions ofroot resorption & repair


Erosion of bone and the deciduous root is not steady &continuous, but may cease briefly, when some repair oferoded cementum & dentine can occur (by cementum).

Bone remodelling also goes on, and the alveolus andcrypt are changing all the time - repeated all along the jaw

DENTINE

ENAMEL


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Osteoblastslaying downbundle bone


Occlusal wear

Bony

interdentalseptum

Basil

TOOTH MOVEMENT

Osteoblasts


Tooth drifts mesiallyby combined actionsof osteoclasts &osteoblasts movingbone, taking toothwith it

Basil



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TOOTH MOVEMENT

Tooth drifts mesially bycombined actions ofosteoclasts & osteoblastsmoving bone, taking toothwith it

Basil


Intra-oral phase

TOOTH ERUPTION

Pre-oral phase


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Once the teeth meet inocclusion, their furthereruption separates the jaws

TOOTH ERUPTION

Once the teeth meet inocclusion, they influenceeach other mechanically

PERIODONTITIS

Periodontalligament

TOOTH

Alveolar bone

GINGIVA


CONNECTIVE TISSUE

resulting in chronicinfection &

inflammation &


loss of teeth


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Gingival recession onto &down the cementum with lossof alveolar-crest bone

PASSIVE ERUPTION

Raising the banana, then peeling the banana

P

ULP

Fate of exposed cementum &dentinal consequences & reactions

Cementum readily abraded &

eaten by oral acids

REPARATIVE DENTINE -response to caries/erosion

DEAD TRACT in Dentine -wide, empty dentinal tubuleseasily colonized by bacteria


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TOOTH MOVEMENTS

DRIFTING e.g., mesially, laterally

AXIAL - in long axis of the tooth

Basil

Occurring in eruption & use

ROTATORY

TILTING

By root growth &bone remodelling

By bone remodelling &PDL reorganization

Combinations of these fourmovements frequently occur

TOOTH MOVEMENT 2

Basil


TILTINGTooth tilts by combinedactions of both osteoclasts& osteoblasts on bone of

each sideof socket


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21

3rd MOLARS TILTING ERUPTION

TILTING mechanism may be useful, e.g., in bringingupright the third molar that starts tilted

Failure can lead to an impacted molar still within the bone

2nd2nd

3rd

3rd

1 32 54 760YEARS

YOUNG CHILDS ERUPTION SEQUENCE

Time of emergence

Root formingCrown forming

KEY

10 2nd Molar

20 Incisor

20 Cuspid

20 2nd PreMolar

Deciduous

Permanent


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10 Incisor

10 Cuspid

1 32 54 760YEARS

YOUNG CHILDS ERUPTION SEQUENCE

10 2nd Molar

20 Incisor

20 Cuspid

20 2nd PreMolar

5-yr CHILDS DENTITION: 0ne arch

5 deciduous teeth working, but 1o incisor root is being resorbed

7 successional/succedaneous teeth developing pre-orally

dental lamina for 3rd molar

Oral

Pre-oral


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5-yr CHILDS DENTITION: 0ne arch

These 12 teeth require a very coordinated remodelling of thebone (& PDL) supporting & enclosing them

Oral

Pre-oral

ERUPTION: Problems

Early eruption

Missing tooth

Impaction - failure to erupt e.g., from too little gap afterpremature loss of deciduous tooth

Delayed eruption

Malocclusion

Tilting (can occur early from germ rotation)

Infra-occlusion (not high enough)

Retained root fragment

Excessive drift


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GINGIVA: Roles

Establishes a seal around the tooth

Adapt to changing oral conditions & eruption

Fastens to the tooth along an extensive area

Connect soft tissue to hard while it

Control oral microbes

Attaches firmly to the bone supporting the tooth

Join with the adjacent aveolar mucosa

Provide sensation for control of biting & chewing

Protect the PDL & alveolar bone

WABeresford

Free & attached gingiva

FREE GINGIVA

ATTACHED GINGIVA

}Epithelial

attachment

TOOTH

Gingival sulcus/ crevice


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3

GINGIVAL EPITHELIUM

Stratified squamouspara-keratinized

very protective barrier,

needing glandularlubrication

piled-up, tightlyattached, & internallyreinforced cells

GINGIVAL EPITHELIUM: Cell types

Keratinocytes

Langerhans APC cell

Melanocyte

Merkel cell

Nerve cell (axon)


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GINGIVAL EPITHELIUM: Cell types

Keratinocytes

LangerhansAPC cellimmunity

Melanocyte tomake & transferpigment

Merkel cellsensory

dead

alive

Nerve cell representedby its axon

GINGIVAL EPITHELIUM: Subtypes

GINGIVAL EPITHELIUM*

SULCULAR/CREVICULAR

EPITHELIUM

Gingival sulcus/ crevice

TOOTH

CUFF/ ATTACHMENTEPITHELIUM

*Keratinization


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EPITHELIAL ATTACHMENT

TOOTH

JUNCTIONAL/ CUFF/ATTACHMENT EPITHELIUM

CUTICLE

BASAL LAMINA

TOOTH

GINGIVA

Alveolarbone

MATRIX -

Ground substanceCollagen I & III fibersElastic fibers

Blood vessels

Nerves, receptorsLymphatics

CELLS -

Fibroblasts & MyofibroblastsMacrophagesMast cellsLeukocytes

GINGIVAL ELEMENTS - Dense connective tissue


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TOOTH

Alveolarbone

Fibroblasts & MyofibroblastsMacrophagesMast cellsLeukocytes

GINGIVAL ELEMENTS - Connective tissue cells

Leukocytes, particularly PMNs &lymphocytes, are very numerous

& infiltrate the epithelium

GINGIVA

The gingiva is in a continuous

inflammatory state

PERIODONTITIS

Periodontalligament

TOOTH

Alveolar bone


CONNECTIVE TISSUE

resulting inchronic infection &

inflammation &


loss of teeth

GINGIVA


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8

GINGIVAL FIBER GROUPS

TRANS-SEPTAL inmedio-distal plane,not shown here

DENTO-GINGIVAL

ALVEOLO-GINGIVAL

GINGIVA

Alveolarbone

CIRCULARDENTO-PERIOSTEAL

Periosteum

TOOTH

TRANS-SEPTAL FIBER GROUP

TRANS-SEPTALin medio-distalplane

Alveolarseptum

TOOTH TOOTH

GINGIVA


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GINGIVAL FIBER GROUPS

DENTO-GINGIVAL

ALVEOLO-GINGIVAL

TOOTH

GINGIVA

Alveolarbone

TRANS-SEPTALif in medio-distalplane, not as

shown here

CIRCULAR

DENTO-GINGIVAL

ALVEOLO-GINGIVAL

CIRCULAR

TRANS-SEPTAL

DENTO-PERIOSTEAL


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PERIODONTAL LIGAMENT/ PDL

PULP

DENTINE

ENAMEL

CEMENTUM

PERIODONTAL

LIGAMENT/ PDLALVEOLAR BONE

GINGIVA

WABeresford





Refinements



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PERIODONTAL LIGAMENT: Roles

The PDL is the means of attaching the toothto the muscle-driven bone for mastication.As a labile connective tissue, it:


senses loadsfor proprioceptive feebackcontrolling muscle actions


supplies & nourishescementum & alveolarbone

defendsagainst microbes

repairsdamage to itself, while preventing

damage to cementum

CONNECTIVE TISSUE ROLES: PDL

Connect/Support

Transport/Nourish

Defend

(Storage)

Control

Repair

Connective tissue

EPITHELIUM

VESSEL

}

The tissues served are also bone & cementum

*

*


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CONNECTIVE TISSUE - Mechanical functions

Supporting - ligament, cartilage, bone

Binding - ligament

Restraining - ligament

Directing - tendon

Separating - fascia

Padding - fat pad

Functions, including padding, all effected by PDL,but adipose tissue is absent

DENSE REGULAR CONNECTIVE TISSUE: Tendon

Bundles of thick

collagen I fibers

{

{

Looser vascular CT

between the bundles -

endotendinuem

Elongated fibroblasts - tenocytes


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DENSE REGULAR CONNECTIVE TISSUE: PDL

Bundles of thickcollagen I fibers

{

{

Looser vascular CTbetween the bundles

- interstitial areasElongated PDL fibroblasts

PRINCIPAL FIBERS

DENTINE

PULP

PDL Interstitial Areas

OBLIQUE & other

FIBER BUNDLES

Interstitial Areas

between


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PDL ELEMENTS - Dense & loose connective tissue

MATRIX -Ground substanceReticular fibersCollagen I fibers


CELLS -Fibroblasts & MyofibroblastsMacrophagesMast cellsLeukocytesCementoblastsOsteoblasts & clasts

& Cementicles & Rests

PDL ELEMENTS - The elastic question

MATRIX - Ground substance Reticular fibers Collagen I fibers

The PDL, like tendon, has the elasticity of bundledcollagen fibers in a water-containing matrix ofproteoglycans & glycoproteins. But it does NOTcontain elastic fibers.

The complication is that elastic fibers comprisemicrofibrilsorienting the elastin, & these are separatemolecular species that have to assemble. The PDLdoes have the microfibrils arranged as OXYTALANfibers. Why? No-one knows.

The final complication is that there is an a fiberintermediate between the elastic & oxytalan fibers - theELAUNIN fiber, also absent from the PDL. Forget it.


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DENTINE

ENAMEL

BONE

GINGIVA

Epithelial diaphragmROOT SHEATH

CEMENTUMPDL

PULP


LATE ERUPTING TOOTH


DENTINE

ENAMEL

BONE

GINGIVA


ROOT SHEATH

CEMENTUM

PDL

PULP

PDL BOUNDARIES

BONE

CEMENTUM

GINGIVA

PULP

Mature

+ while developing

ROOT SHEATH

MESENCHYME


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TOOTH TISSUES: Cell Sources

DENTAL LAMINA

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

DENTAL ORGAN

ALVEOLAR BONE

PULP

DENTINE

ENAMEL

CEMENTUM

PDL

A BONE

TOOTH

Crest

Ameloblasts

Odontoblasts

CT cells

Cementoblasts

Fibroblasts


TOOTH GERM: all crown-forming elements present

Ameloblasts

Stellatereticulum

Cervical loopmoving apically

to define extent

of crown



cusp enamelformed byameloblasts

Capillaries now close to

synthesizing ameloblasts

Dentine

2nd


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ENAMEL

REDUCED

DENTALEPITHELIUM

HERTWIGS

ROOTSHEATHgrows tolengthen root

DENTINE

PULP





Other sacmesenchymal

cells construct

PDL & somealveolar bone

Fibroblasts

E

D

E

D

Reactivated cementoblastslay down cementoid

E

D

E

D

GROWTH OF CEMENTUM = PDL anchoring

Cementoid becomesanother layer of cementum.Cells make more cementoid

PDL

fibers

PDL fibers becomeimbedded in newlyformed cementum -

Sharpeys fibers


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CERVICAL REGION

Periodontalligament

TOOTH

Alveolar bone

GINGIVA

EPITHELIAL ATTACHMENT-

CONNECTIVE TISSUE

PDL CERVICAL FIBER GROUPS

TOOTH

GINGIVA

Alveolarbone

(GINGIVAL LIGAMENT)

TRANS-SEPTALif in medio-distalplane, not asshown here

ALVEOLAR-CREST

HORIZONTAL

CEMENTUM


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PDL TRANS-SEPTAL FIBER GROUP

TRANS-SEPTALin medio-distalplane

Alveolarseptum

TOOTH TOOTH

GINGIVA

DENTINE

PULP

PDL FIBER GROUPS II

HORIZONTAL

OBLIQUEthe major group

APICAL


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III PDL INTER-RADICULAR GROUP

Inter-radicular

Inter-radicularbony septum

FIBER GROUPS: A classification

Inter-radicular

Horizontal

Oblique

Apical

Alveolar-crest

GINGIVAL LIGAMENT

ALVEOLO-DENTAL

Trans-septal

INTERDENTAL


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13

D

E

N

T

I

N

E

PULP

Non-imbeddedends of PDL fibers

meet & attach inINTERMEDIATEPLEXUS

{

This arrangementprovides for greater

ease of remodelling &readjustment of theplexus for growth &altered function. Butremodelling occursthroughout the PDL

PDL: Intermediate plexus

TOOTH MOVEMENT

Osteoblasts


Tooth drifts mesiallyby combined actionsof osteoclasts &osteoblasts movingbone, taking toothwith it


Plus PDLreorganization


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Interstitial AreaPDL in Cross-sectionWider on bone-

depository side

Bundle

Narrow on bone-resorptive side

DENTINE

PULP

BONE

CEMENTUMP

D

L

Reduction in # &size of principal

fibers

Periodontal reactions to disuseLoss ofalveolar bone

Bundledefinitionlost

PDLnarrower allaround

DENTINE

PULP

BONE

CEMENTUMthickensP

D

LCEMENTUMlosesSharpeysfibers

Mild bonedepositionon wall


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16

RESTS & CYSTS

DENTINE

ENAMEL

BONE

ROOT SHEATH

PDL

PULP


Any buried epithelial cells can proliferate &start to secrete, forming a cyst., e.g., remnantsof dental lamina, thyroglossal duct, etc

P

ULP

CEMENTICLES

Hard mineralized bodies foundentirely in the periodontal ligamentor partially imbedded in cementum


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WABeresfordTOOTH TISSUES: Pulp

PULP

DENTINE

ENAMEL

CEMENTUM

PERIODONTAL

LIGAMENT/PDL

ALVEOLARBONE

GINGIVA

DENTAL PULP: Functions

Service tissue keeping its Odontoblasts alivefor slow defensive responses in the dentine

Providing antimicrobial defense for thedentine and itself

Providing sensory feedback from the dentine,but for what purposes?


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PULP

DENTINE

ENAMEL

CEMENTUM

PERIODONTALLIGAMENT/PDL

ALVEOLAR BONE

GINGIVA

Service tissue keeping its Odontoblasts alive for slowdefensive responses in the dentine

Providing antimicrobial defense for the dentine and itself

Providing sensory feedback from the dentine, but forwhat purposes?

WABeresfordTOOTH TISSUES: Pulp & its roles

PULP CHAMBER

CORONAL PULP HORN

ACCESSORYCANAL

ROOT CANAL

APICAL FORAMEN


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PULP REGIONS

ODONTOBLASTLAYER

PULP PROPER/PULP CORE

Cell-poorZONE OF WEIL- peripheral pulp

PULP ELEMENTS - Mucoid connective tissue

MATRIX -Ground substanceReticular fibers

Collagen Ifibers Elastic fibers


CELLS -

OdontoblastsFibroblastsMacrophagesMast cellsLeukocytes


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PULP INNERVATION

Nerves: sensory (V) to

PULP

ODONTOBLASTS

DENTINAL TUBULES

Blood vessels

Nerves:

autonomic

12 3

1

2

3

Sub-odontoblastic plexusin cell-poor zone of Weil

PULP ELEMENTS - Mucoid connective tissue

MATRIX - Groundsubstance Reticularfibers Collagen I fibersElastic fibers


CELLS -OdontoblastsFibroblasts

MacrophagesMast cellsLeukocytes

& Denticles & Fibrosis with aging


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PULP

DENTICLES/ PULP STONES

Hard mineralized bodies found inthe pulp or the dentine

TWO TYPES:

1 TRUE - constructed of dentine

by ectopic odontoblasts & showingdentinal tubules

2 FALSE - mineralized connective

tissue, etc, (not made of dentine)

Both may show layering/lamellar patterns

from incremental growth

P

ULP

DENTICLES/ PULP STONES:further classification by place

Hard mineralized bodies found in the pulpor the dentine

THREE SUBTYPES:

1 FREE - in the pulp

2 IMBEDDED - enclosed in thedentine as this has slowly grown

inwards

3 ATTACHED - partly imbedded


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TOOTH GERM: Pulp development

DENTAL LAMINA

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

DENTAL ORGAN

MESENCHYME

ALVEOLAR BONE


DENTAL LAMINA

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

DENTAL ORGAN

MESENCHYME

ALVEOLAR BONE

PULP

DENTINE

ENAMEL

CEMENTUM

PDL

A BONE


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DENTAL LAMINA

DENTAL PAPILLA

mesenchyme

DENTAL SAC/FOLLICLE

DENTAL ORGAN

ALVEOLAR BONE

PULP

DENTINE

ENAMEL

CEMENTUM

PDL

A BONE

TOOTH

Crest

Ameloblasts

Odontoblasts

CT cells

Cementoblasts

Fibroblasts



DENTAL LAMINA

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

DENTAL ORGAN

ALVEOLAR BONE

PULP

DENTINE

ENAMEL

CEMENTUM

PDL

SUPPORTINGBONE

TOOTH

LAMINA DURA

Plate

Spongy bone


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TOOTH GERM

DENTAL LAMINA


Stellate reticulum

Inner dental epithelium

Stratum intermedium

DENTAL PAPILLA

DENTAL SAC/FOLLICLE

Vessels Nerves

HERTWIGSROOTSHEATHgrows tolengthen root

PULPdifferentiates





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EXTRACELLULAR MOLECULAR INTERACTIONS 1

Further assemblyof the molecules to make larger &eventually visible structures, such as fibrils

Modificationof the molecules, e.g., cross-linking, to make

them resistant to digestion

Deliberate breakdownof the molecules by the forming cellsfor turnover and renewal, by proteases & other enzymesControlled breakdown, with more synthesis & assembly,provides for remodeling & adaptation of ECM, e.g., to

heavier load in tendon or cartilage

Some of these enzymes, e.g. collagenase, include a zinc atom& require Ca2+ to work - hence Matrix Metalloproteinases, e.g.MMP-3

ECM MOLECULAR INTERACTIONS - Pathology 1

The inhibitorsof these enzymes go under the abbreviationTIMPs- Tissue Inhibitors of MMPs; & are also made byfibroblasts & other matrix-influencing cells

Some of these enzymes, e.g. collagenase, include a zinc

atom & require Ca2+ to work - hence MatrixMetalloproteinases, e.g. MMP-3

Unintended degradationby enzymes released from cells,e.g., leukocytes, engaged in defensive reactions.

ECM is the battlegroundfor defenses initially targeted atmicroorganisms.

--itises occur throughout the body, & are real hazards tocomfort & life, e.g., endocarditis weakens & distorts heartvalves


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Unwanted degradationby bystander inclusion in cytokinesignaling pathways of defensive cells

M Lymphocytes of inner joint synoviumIL-1

Articularchondrocytes

IL-1Joint cartilage cells alsorespond to the signal:enzymes enzyme inhibitorsproteoglycans

= an inappropriate response causing cartilage matrixdestruction - ARTHRITIS


Unwanted degradationby bystander inclusion in cytokinesignaling pathways of defensive cells

M Lymphocytes of inner joint synoviumIL-1

Articularchondrocytes

IL-1

Joint cartilage cells alsorespond to the signal:enzymes enzyme inhibitors

proteoglycans

= an inappropriate response causing cartilage matrix

destruction - ARTHRITIS



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Unwanted degradationby:

microbes trying to colonize, e.g., using bacterial hyaluronidase

to liquify ground substance

metastasizing cancer cells breaking through basal laminae

& connective tissues

Unwanted synthesis - the formation of excess collagen,clogging organs with delicate blood-cell relations.

Cytokines released by activated macrophages triggersynthesis in fibroblasts, causing cirrhosisin the liver and

fibrosisin kidney, lung, marrow, etc


Bad assembly - genetically defective fibrillin makes aninadequate scaffold for elastin deposition weak aorta,slack connective tissues, etc, of Marfans syndrome


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TOOTH

LIP

LIP

HARD PALATE SOFT PALATE

TONGUE

ORAL STRUCTURES Sagittal view

SALIVARY GLANDS

ALVEOLAR BONE+ CHEEK WABeresford

ORAL LINING - oral mucosa of stratifiedsquamous epithelium + lamina propria

LIP & CHEEK

TONGUE

MANDIBLE & MAXILLA Alveolar bone

SALIVARY GLANDS - major & minor

HARD PALATE

SOFT PALATE

ORAL STRUCTURES

TOOTH


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Parotid

Sub-lingual

Sub-mandibular

MINOR

Labial

Buccal

Lingual

Palatal

serous

mixed - SERO-mucous

mixed - MUCO-serous

mucous

mucous

serous, mucous & mixed

mucous

MUCOUS TUBULE

MYOEPITHELIAL CELL

SEROUS DEMI-LUNE

BL

SEROUS ALVEOLUS

MUCOUS TUBULE

with


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PROTECTION

SALIVA - Functions

ALIMENTARYFood approval: taste, texture

Mastication

Swallowing

Digestion

OTHER Vocalization

Excretion ?

Spit as a tool

EpitheliallubricationAnti-microbial materials

For tooth: Rinsing BufferingMineralization Pellicle coat

PROTECTION

SALIVA - Functions

ALIMENTARY Food approval: taste, texture

Mastication

SwallowingDigestion

OTHER Vocalization

Excretion ?

Spit as a tool

EpitheliallubricationAnti-microbial materials

For tooth: Rinsing BufferingMineralization Pellicle coat

MATERIALSWaterMucins (glycoproteins)

Antibodies IgAsLysozyme DefensinsIons - bufferingIons - tooth mineralAmylaseIodine


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CleaningShowing disapproval

SALIVA - Functions & means

Food approval: taste, texture

Mastication

Swallowing

Digestion

Vocalization

Excretion ?

Spit as a tool

Epithelial lubricationAnti-microbial materials

For tooth: Rinsing Buffering MineralizationPellicle coat Water) Ions - buffering Ions - tooth mineral

Antibodies IgAs Lysozyme DefensinsWater Mucins

Touch & taste receptors & nerves

Water Mucins

Amylase

Iodine

Water

Water Mucins Mucous glands concentratedat back of mouth

PANCREATIC DUCTS: model for salivaryDuodenalpapilla

Exocrine acini

Lobule

}Principal duct

Interlobular duct

Intralobular ducts

Intercalated ductsSalivary gland is more compact,has denser CT, & no islets


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5

SALIVARY DUCTS

Principal duct

Interlobular duct

Intralobular duct

Intercalated duct

SALIVARY DUCTS: Epithelia

Principal duct

Interlobular duct

Intralobular duct

Intercalated duct

Stratified cuboidal /columnar

Simple cuboidal/columnar

Simple cuboidal

Low cuboidal/squamous

Accompanied by CT

Accompanied by CT

Be prepared for pseudo-strat & mixed types


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SALIVARY DUCTS: Synonyms

Principal duct

Interlobular duct

Intralobular duct

Intercalated duct

Whartons, Stensens, etc

Excretory (drain-pipe)

Secretory/Striated (from basalmitochondria and membraneinfoldings for ion transport)

Classifications by site versusfunction

Intercalated (in between)

Eosinophilic

PAROTID GLAND

SEROUS ACINi

INTRA LOBULARDUCT

INTERCALATED DUCT

INTER LOBULAR DUCT


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SUBMANDIBULAR GLAND

SEROUS ACINi

INTRA LOBULARDUCT

INTER LOBULAR DUCTA FEW MIXEDMUCOUSTUBULES

SEROUSdemilune

SUBLINGUAL GLAND

INTER LOBULAR DUCT

MIXEDMUCOUSTUBULES

SEROUSdemilune

PUREMUCOUSTUBULE

INTRA LOBULAR DUCT(few & not striated)


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DUCT SYSTEM complex tributaries

Principal duct

Interlobularducts

Intralobular ducts

Intercalated ducts

The scheme does not dojustice to the length andbranching of a duct sytem for alarge compound gland. Thinkstreams entering Deckers creek all theway to the mouth of the Mississippi.

So one term, e.g,intralobular duct, coversa variety of widths and

even epithelial types,and there will betransitional forms, andstrange section cuts.


MINOR

Labial

Buccal

Lingual

Palatal

mucous

mucous

serous, mucous & mixed

mucous


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Tongue papillae

Muscular core

Nerve

Sub-lingual gland

Duct

Blood vessels

Connectivetissue

TONGUE

Lingual gland

TONGUE - dorsum

TONSILS

CIRCUMVALLATEPAPILLA

FILIFORM PAPILLAE

FUNGIFORM PAPILLA

Taste bud

Trench


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TONGUE - dorsumTONSILS

CIRCUMVALLATE PAPILLA

FILIFORM PAPILLAE

FUNGIFORM PAPILLA

Neither associatedwith glands

von Ebnersserous glandsfor taste

Webers posterior mucousglands to flush out tonsils

Blandin/Nuhnsmixed anteriorlingual glands

LIPRED MARGINVERMILION BORDER

HAIRY SKIN

MUSCLE

LABIAL MUCOSAthick strat squam ep

LABIALGLANDmucous

RED MARGINkeratin thins awayno follicles or glands


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CHEEK

HAIRY SKIN

NO RED MARGIN

BUCCAL MUCOSAthick strat squam ep

BUCCAL GLANDmucous

MUSCLE

ADIPOSE TISSUE

HARD PALATE: Cross-section

PALATE BONE

RAPHE

ADIPOSE CT - anteriorMUCOUS GLANDS -posterior


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12

GUT MOTOR INNERVATION

with H & E staining, the only neural elements seen are the neuronbodies & characteristic nuclei. The plexuses of fibers are unseen.

Unmyelinated autonomic nerve

muscle

submucosa

Auerbachs myenteric plexus

Meissners submucosal plexus Rare neuron bodies of

plexus

Clumped

neurons of Asplexus

neurons are multipolar, with dendrites!

SALIVARY GLAND INNERVATION

with H & E staining, the only neural elements seen are the few neuronbodies & characteristic nuclei. The plexuses of fibersto acinar cells,myoepithelial cells, ducts, & vessels are unseen.

Unmyelinated autonomic nerve

Clumped neuronsof minor ganglia

Parasympathetic neurons are multipolar, with dendrites!

Parasympathetic post-gangionic fibers

Sympathetic post-gangionic fibers


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TEMPOROMANDIBULAR JOINT/ TMJ

One jaw has twoTMJs * *

The joint is a freely moveablesynovial jointwith a cavity

Each joint is between thecondyleof the mandible andthe temporal boneof the skull

There are actually two cavitiesbecauseof an intervening cushioning disc

There are other differencesfrom thetypical synovial joint

CC

WABeresford

CONDYLE

CORONOID PROCESS

RAMUS

BODY

MENTAL SYMPHYSIS

PARTS OF THE MANDIBLE

ALVEOLAR RIDGE

TEETHCONDYLAR

PROCESS

ANGLE


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EXT AUD MEATUS

RELATED SKULL FEATURES

FOSSAARTICULARTUBERCLE

ZYGOMAin outline

STYLOID PROCESS

Lateral pterygoidplate (deep)

Why so much ramus & coronoid process?

CORONOID PROCESS

RAMUS

BODY

ATTACHMENT SURFACE FORMASTICATORY MUSCLES

These muscles enclose, define & stabilize the TMJ:And capsules & ligaments play a role


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Lateral ligament

FIBROUS ATTACHMENTS TO SKULL

Stylomandibularligament

Joint capsule

Sphenomandibularligament inserts onmedial side (lingula)

DISLOCATION beyond art. tubercle

These attachmentsallow an anteriordislocationof themandible,

oral histology compendium

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