background image

Lec.

Or

alHi

st

ol

ogy

.

PERI

ODONTALLI

GAMENT(

PDL)

Theper

i

odont

i

um i

sdef

i

nedast

hoset

i

ssuessuppor

t

i

ngandi

nvest

i

ngt

het

oot

h

andconsi

stofcement

um ,per

i

odont

all

i

gament

,bonet

hel

i

ni

ngal

veol

us(

socket

)

andt

hatpar

tt

heofgi

ngi

valf

aci

ngt

het

oot

h.

PERI

ODONTALLI

GAMENT(

PDL)

defi

neasi

st

hedensef

i

br

ousconnect

i

vet

i

ssuet

hatoccupi

est

heper

i

odont

alspace

bet

weent

her

ootoft

het

oot

handbonef

or

mi

ngt

hesocketwal

l

.

Rangesi

nt

hi

cknessbet

ween0.

15and0.

38mm andi

st

hi

nnesti

nt

hemi

ddl

epor

t

i

on

oft

her

oot

.

Or

i

gi

nandDevel

opmentOfPer

i

odont

all

i

gament

PDLi

sder

i

vedfr

om t

hedent

alf

ol

l

i

cl

et

hatenvel

opst

hedevel

opi

ngt

oot

hger

m.

Somedel

i

cat

ef

i

berbundl

esoft

hef

or

mi

ngPDLappearasr

ootfor

mat

i

onbegi

ns.

Thei

nnermostcel

l

sneart

hef

or

mi

ngr

ootdi

f

fer

ent

i

at

ei

nt

ocement

obl

ast

sandl

ay

downcement

um,whi

l

et

heout

er

mostcel

l

sdi

f

f

er

ent

i

at

ei

nt

oost

eobl

ast

sandf

ur

ni

sh

t

hel

i

ni

ngoft

hebonysocket

.Themor

ecent

r

al

l

yl

ocat

edcel

l

sar

edi

f

f

er

ent

i

at

edi

nt

o

fi

br

obl

ast

swhi

chsynt

hesi

zet

hef

i

ber

sandt

hegr

oundsubst

anceoft

hePDL.The

fi

ber

soft

hePDLbecomeembeddedi

nnewl

ydevel

opedcement

um andal

veol

ar

bone(

Shar

pey’

sfi

ber

s).

Hi

st

ol

ogi

calst

r

uct

ur

eoft

heper

i

odont

all

i

gament

ThePDLconsi

stoffi

ber

s,cel

l

s,gr

oundsubst

ance,andot

herst

r

uct

ur

es

suchasbl

oodvessel

sandner

ves.

A.

fi

ber

soft

heper

i

odont

all

i

gament

(

1)Col

l

agenfi

ber

s

Col

l

agenoft

heper

i

odont

all

i

gament

Theper

i

odont

alcol

l

ageni

smost

l

yt

ypeI

,col

l

agenTypeI

I

Icol

l

agen(

about20%)

.

Much of t

he col

l

agen i

s gat

her

ed t

oget

her t

o for

m bundl

es whi

ch ar

e

appr

oxi

mat

el

y5µm i

ndi

amet

er

.

Thesebundl

esar

et

er

medt

hepr

i

nci

palf

i

ber

soft

heper

i

odont

all

i

gament

.


background image

Thepr

i

nci

palf

i

ber

sappearmor

enumer

ousatt

hei

rat

t

achment

st

ocement

um

t

hanatt

heal

veol

arbone.

Thepr

i

nci

palf

i

ber

soft

heper

i

odont

all

i

gamentwhi

char

eembeddedi

ncement

um

andi

nt

hebonel

i

ni

ngt

het

oot

hsocketar

et

er

medShar

pey’

sfi

ber

s.

Thehor

i

zont

all

i

nesi

nt

heboneandcement

umr

epr

esentt

heShar

pey’

sfi

ber

s.

Thepr

i

nci

palf

i

ber

s:Theyar

ef

or

medofcol

l

agenbundl

es,whi

char

ewavyi

ncour

se

andar

ear

r

angedi

nt

hr

eegr

oups

a)Gi

ngi

valfi

ber

s:

1-Dent

o-

gi

ngi

valfi

ber

s:

-

2-Al

veol

o-

gi

ngi

valgr

oup:

3-Ci

r

cul

argr

oup:4-Dent

o-

per

i

ost

ealf

i

ber

s.

b)Thet

r

anssept

all

i

gament

:I

tconnect

st

woadj

acentt

eet

h.Thel

i

gamentr

unsf

r

om

t

hecement

umofonet

oot

hovert

hecr

estoft

heal

veol

ust

ot

hecement

umoft

he

adj

acentt

oot

h.

Funct

i

on:Resi

st

smesi

alanddi

st

alt

oot

hsepar

at

i

on.

c)Theal

veol

odent

all

i

gament

:

1-

Al

veol

arcr

estgr

oup:at

t

achedt

ot

hecement

umj

ustbel

owt

hecementenamel

j

unct

i

onandr

unni

ngdownwar

dandoutwar

dt

oi

nser

ti

nt

ot

her

i

m oft

heal

veol

us.

Funct

i

on:r

esi

st

sver

t

i

calandi

nt

r

usi

vefor

ces.

2-

Hor

i

zont

algr

oup:j

ustapi

calt

ot

heAl

veol

arcr

estgr

oupandr

unni

ngatr

i

ght

angl

est

ot

hel

ongaxi

soft

het

oot

hfr

om cement

umt

obonej

ustbel

owt

heAl

veol

ar

cr

est

Funct

i

on:r

esi

st

shor

i

zont

alandt

i

ppi

ngfor

ces.

3-Obl

i

quegr

oup:t

hemostnumer

ousi

nt

hepdlandr

unni

ngf

r

omt

hecement

umi

n

an

obl

i

quedi

r

ect

i

ont

oi

nser

ti

nt

obonecor

onal

l

y.

Funct

i

on:Per

for

mst

hemai

nsuppor

toft

het

oot

hagai

nstmast

i

cat

or

y

f

or

ces.

*Resi

st

sver

t

i

calandi

nt

r

usi

vef

or

ces.

4-Api

calgr

oup:Thebundl

esr

adi

at

i

ngf

r

om t

hecement

umar

oundt

heapexoft

he


background image

r

oott

ot

hebonefor

mi

ngt

hebaseoft

hesocket

.

Funct

i

on:r

esi

st

sver

t

i

calf

or

ce.

5-I

nt

err

adi

cul

argr

oup:f

oundonl

ybet

weent

her

oot

soft

hemul

t

ir

oot

edt

eet

h.And

r

unni

ngf

r

omcement

umi

nt

ot

hebonef

or

mi

ngt

hecr

estoft

hei

nt

err

adi

cul

ar

sept

um.

Funct

i

on:r

esi

st

sver

t

i

calandl

at

er

alf

or

ces.

(

2)Oxyt

al

anfi

ber

s

Theoxyt

al

anfi

ber

sar

eoft

ent

er

mi

nat

ear

oundbl

oodvessel

s.

Theoxyt

al

anfi

ber

svar

yi

nsi

zef

r

om 0.

5-

2.

5mm i

ndi

amet

erandconst

i

t

ut

enomor

e

t

hanabout3%oft

heext

r

acel

l

ul

arf

i

bercomposi

t

i

on.Theyneedspeci

alst

ai

nst

obe

demonst

r

at

edThesear

eel

ast

i

cf

i

ber

sr

uni

n obl

i

quedi

r

ect

i

ononeendbei

ng

embeddedi

nboneorcement

um andt

heot

heri

nt

hewal

lofbl

oodvessel

s.Att

he

api

calr

egi

ont

heyfor

macompl

exnet

wor

k.

Funct

i

onhasnotbeendet

er

mi

nedf

ul

l

yt

heyar

et

houghtt

o1.r

egul

at

evascul

arfl

ow

i

nr

el

at

i

ont

ot

oot

hfunct

i

onbecauset

heyar

eel

ast

i

c,2.

suppor

tt

hebl

oodsvessel

si

n

t

heper

i

odont

all

i

gament

.3-Hel

pf

i

br

obl

ast

smi

gr

at

i

on.

B.

Thecel

l

sofper

i

odont

all

i

gamentar

e

1.Synt

het

i

cCel

l

sa) Fi

br

obl

ast

sb) Ost

eobl

ast

s c)Cement

obl

ast

s

2.

Resor

pt

i

veCel

l

sa) Ost

eocl

ast

sb) Cement

ocl

ast

sc)

Fi

br

obl

ast

s

3.

Undi

ffer

ent

i

at

edmesenchymalcel

l

s(

Pr

ogeni

t

orCel

l

s)

4.

Epi

t

hel

i

alCel

lr

est

sofmal

assez

5.

Connect

i

veTi

ssuecel

l

s

a)Mastcel

l

sb)Macr

ophages

(1) Synt

het

i

ccel

l

s:

a)Fi

br

obl

ast

scel

ls


background image

Per

i

odont

alf

i

br

obl

ast

s,bei

ngact

i

vecel

l

s,havel

ownucl

ear

-

cyt

opl

asmi

cr

at

i

os,and

eachnucl

euscont

ai

nsoneormor

epr

omi

nentnucl

eol

i

.

Fi

br

obl

ast

sar

et

hemostcommoncel

l

si

nper

i

odont

all

i

gament

.Theyconst

i

t

ut

e

about65%oft

ot

alpopul

at

i

on.

Theyappearasovoi

dorel

ongat

edcel

l

swi

t

hpseudopodi

al

i

kepr

ocess.

Theyar

eusual

l

yfoundpar

al

l

elt

ocol

l

agenf

i

ber

s.

Funct

i

ont

heyhel

pi

nsynt

hesi

sandr

esor

pt

i

onofext

r

acel

l

ul

arconnect

i

vet

i

ssue.

b)Ost

eobl

ast

scel

l

s

Al

ayerofost

eobl

ast

sl

i

ni

ngt

heal

veol

arbone.

Theyar

ebonef

or

mi

ngcel

l

s.

C)Cement

obl

ast

scel

l

s

Theyhel

pi

nfor

mat

i

onofcement

um.

(2)

Resor

pt

i

vecel

l

s

a)Cement

ocl

ast

scel

l

s

Ascement

umnotr

emodelt

hesecel

l

sar

enotnor

mal

l

yf

oundi

nl

i

gment

.Thesecel

l

occuronl

yi

ncer

t

ai

npat

hol

ogi

calcondi

t

i

ons,

dur

i

ngr

esor

pt

i

onofdeci

duoust

eet

h

anddur

i

ngor

t

hodont

i

ct

her

apy.

b)Ost

eocl

ast

scel

l

s

Theyar

eboner

esor

bi

ngcel

l.Ani

ncr

easei

nnumberofOst

eocl

ast

sar

eseenwher

e

bonei

sundergoi

ngact

i

ver

esor

pt

i

on.

(

3)Undi

ffer

ent

i

at

edmesenchymalcel

l

s(

Pr

ogeni

t

orcel

l

s)

Canunder

gomi

t

ot

i

cdi

vi

si

on,Candi

f

f

er

ent

i

at

et

odi

f

f

er

entt

ypesofcel

l

s,havesmal

l

,

cl

osed-f

acenucl

eus,l

i

t

t

l

eamountofcyt

opl

asm,f

oundcl

oset

obl

oodvessel

s.

(

4)Epi

t

hel

i

alr

estofMal

assez’

st

hesegr

oupsofepi

t

hel

i

alcel

l

sbecomel

ocat

edi

n


background image

t

hemat

ur

ePDLaf

t

ert

hedi

si

nt

egr

at

i

onofHer

t

wi

gepi

t

hel

i

alr

ootsheat

hdur

i

ngt

he

f

or

mat

i

onoft

her

oot

.

(

5)Connect

i

vecel

l

s

Def

encecel

l

s:Mastcel

l

s,Macr

ophagest

hatder

i

vedf

r

ommonocyt

esar

epr

esenti

n

l

i

gament

.

C.Gr

oundsubst

ance

Thegr

oundsubst

ancei

sananamor

phousbackgr

oundmat

er

i

alt

hatbi

ndst

i

ssue

andf

l

ui

ds.

i

t

consi

st

smai

nl

yofpr

ot

ei

nsandpol

ysacchar

i

des.gr

oundsubst

ance

cont

ai

nsabout70%wat

er

.

Al

lcomponent

soft

heper

i

odont

all

i

gamentgr

ound

subst

ancear

epr

esumedt

obesecr

et

edbyf

i

br

obl

ast

s.

Thegr

oundsubst

ancei

s

t

houghtt

ohavemanyi

mpor

t

antfunct

i

ons:

1.

hel

psi

nt

r

anspor

t

i

ngi

onandwat

er

br

i

ngandexchangeandal

sohel

psi

ncar

r

i

ngt

hewastpr

oduct

sfr

omcel

lt

obl

ood

vessel

s,

2.cont

r

olofcol

l

agenf

i

br

i

l

l

ogenesi

sandf

i

beror

i

ent

at

i

on.

D.

I

nt

er

st

i

t

i

alt

i

ssue

t

heyar

efoundbet

weent

hef

i

ber

soft

hePDL

Theyar

ear

east

hatcont

ai

nsomeoft

hebl

oodvessel

s,l

ymphat

i

c,andner

ves.They

sur

r

oundedbyl

ooseC.

T

E.

Bl

oodvessel

s

Thebl

oodvessel

st

r

avelfr

om api

calt

ooccl

usal

.

Mai

nbl

oodsuppl

yi

sf

r

omsuper

i

orandi

nfer

i

oral

veol

arar

t

er

i

es.Thebl

oodvessel

s

ar

eder

i

vedfr

omt

hefol

l

owi

ng:

1.Br

anchesfr

omapi

calvessel

s:vessel

st

hatsuppl

yt

hedent

alpul

p.

2.Br

anchesfr

omi

nt

r

a-

al

veol

arvessel

s:

-Vessel

sr

unhor

i

zont

al

l

yandpenet

r

at

et

he

al

veol

arbonet

oent

eri

nt

ot

heper

i

odont

all

i

gament

3.Br

anchesf

r

omgi

ngi

valvessel

s:

-Thear

t

er

i

ol

esandcapi

l

l

ar

i

esr

ami

f

yandf

or

ma

r

i

chnet

wor

k.Ri

chvascul

arpl

exusi

sf

oundatt

heapexandi

ncer

vi

calpar

tof

l

i

gament

..

Adensevenousnet

wor

ki

spar

t

i

cul

ar

l

ypr

omi

nentar

oundt

heapexoft

heal

veol

us.

 


background image

F.

Lymphat

i

cs 

Anet

wor

kofl

ymphat

i

cvessel

sf

ol

l

owi

ngt

hepat

hoft

hebl

oodvessel

spr

ovi

dest

he

l

ymphdr

ai

nageoft

heper

i

odont

all

i

gament

.

G.

Ner

vesofper

i

odont

all

i

gament

Thener

vesar

et

hebr

anchesofsecondandt

hi

r

ddi

vi

si

onoffi

f

t

hcr

ani

alner

ve

(

t

r

i

gemi

nalner

ve)andf

ol

l

ow samepat

hasbl

oodvessel

s.Thesener

vefi

ber

s

pr

ovi

desenseoft

ouch,pr

essur

e,pai

nandpr

opr

i

ocept

i

ondur

i

ngmast

i

cat

i

on.The

ner

vef

i

ber

sent

er

i

ngt

heper

i

odont

all

i

gamentar

eder

i

vedf

r

om t

wosour

ces.Some

ner

vebundl

esent

erneart

her

ootapexandpassupt

hr

ought

heper

i

odont

all

i

gament

.

Ot

her

sent

ert

hemi

ddl

eandcer

vi

calpor

t

i

onsoft

hel

i

gamentasf

i

nerbr

anches

t

hr

oughopeni

ngi

nt

heal

veol

arwal

l

s.Per

i

odont

alner

vef

i

ber

sar

ebot

hmyel

i

nat

ed

andunmyel

i

nat

ed.

Funct

i

onsofper

i

odont

all

i

gament

1.Suppor

t

i

vefunct

i

on

byat

t

achi

ngt

het

oot

ht

ot

hesur

r

oundi

ngal

veol

arbonepr

oper

.

 Thi

sf

unct

i

oni

s

medi

at

edpr

i

mar

i

l

ybyt

hepr

i

nci

palf

i

ber

soft

heper

i

odont

all

i

gamentt

hatf

or

m a

st

r

ongf

i

br

ousuni

onbet

weent

her

ootcement

um andt

hebone.

 Theper

i

odont

al

l

i

gamental

soser

vesasashock-

absor

berbymechani

smst

hatpr

ovi

der

esi

st

ancet

o

l

i

ghtaswel

lasheavyfor

ces.

 Li

ghtf

or

cesar

ecushi

onedbyi

nt

r

avascul

arfl

ui

dt

hat

i

sfor

cedoutoft

hebl

oodvessel

s.

 Moder

at

ef

or

cesar

eal

soabsor

bedbyext

r

a

vascul

art

i

ssuefl

ui

dt

hati

sf

or

cedoutoft

heper

i

odont

all

i

gamentspacei

nt

ot

he

adj

acentmar

r

ow spaces.

 Theheavi

erf

or

cesar

et

akenupbyt

hepr

i

nci

palf

i

ber

s.

Bl

oodvessel

sandal

lt

hecomponent

soft

hel

i

gamentactt

oget

herasahydaul

i

c

damper

orshockabsor

berwi

t

h t

hegr

ound subst

anceand t

het

i

ssuefl

ui

d.

 

t

he

gr

oundsubst

ancepr

esentbet

weent

hef

i

ber

sofpdli

sr

i

chi

nwat

ercont

entand

t

her

ef

or

eaddupt

ot

hesuppor

t.

2.Remodel

i

ngfunct

i

on

bypr

ovi

di

ngcel

l

st

hatar

eabl

et

of

or

m aswel

lasr

esor

bal

lt

het

i

ssuest

hatmakeup


background image

t

heat

t

achmentappar

at

us,i

.

e.bone,cement

um andt

heper

i

odont

all

i

gament 

Undi

f

f

er

ent

i

at

ed ect

omesenchymalcel

l

s,l

ocat

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ent

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at

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al

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m bone(

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ast

s)

,cement

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,and connect

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esor

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sandcement

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)

.

3-Sensor

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all

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mechani

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mat

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essur

eon mast

i

cat

i

onand

el

i

ci

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sevent

hemi

l

destf

or

ceact

i

nguponat

oot

h.

4-Nut

r

i

t

i

vefunct

i

on:Thebl

oodvessel

si

nt

heper

i

odont

all

i

gamenthasagoodbl

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suppl

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ovi

denut

r

i

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l

soft

hel

i

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i

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i

on The pr

ot

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i

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unct

i

on oft

he per

i

odont

all

i

gamenti

s

achi

evedby:

a-Thepr

i

nci

palf

i

ber

s.

b-Thebl

oodvessel

s.

c-Thener

ves.

a-Thepr

i

nci

palfi

ber

s:Thear

r

angementoft

hef

i

berbundl

esi

nt

hedi

ff

er

entgr

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i

swel

ladapt

edt

oful

f

i

l

lt

hef

unct

i

onsoft

heper

i

odont

all

i

gament

.

Theal

veol

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al

l

i

gamentt

r

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mst

hemast

i

cat

or

ypr

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eexer

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edont

het

oot

hi

nt

ot

ensi

onor

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r

act

i

onont

hecement

um andbone.

I

ft

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t

edf

or

ceonat

oot

hi

st

r

ansmi

t

t

edas

pr

essur

et

hi

swi

l

ll

eadt

odi

f

f

er

ent

i

at

i

onofost

eocl

ast

si

nt

hepr

essur

ear

eaand

r

esor

pt

i

onofbone.

b-Thebl

oodvessel

s:

Thecapi

l

l

ar

i

esfor

m ar

i

chnet

wor

k,t

heyar

ear

r

angedi

nf

or

m

ofacoi

landat

t

achedt

oboneandcement

um t

hr

ought

heoxyt

al

anf

i

ber

s.Thi

s

ar

r

angementmakesi

tpossi

bl

ewhenpr

essur

ei

sexer

t

edont

het

oot

h,t

hebl

ood

doesnotescapei

mmedi

at

el

yf

r

om t

hecapi

l

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ar

i

esandt

husbuff

er

i

ngt

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act

i

onbefor

ei

tr

eachest

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hebl

oodi

nt

hecapi

l

l

ar

i

esmaybe

si

mul

at

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oahydr

aul

i

cbr

ake

c-Thener

ves:Byi

t

smechanor

ecept

or

sner

ves.

Cl

i

ni

calconsi

der

at

i

ons

1.Thel

i

gamenti

st

hi

ckeri

nfunct

i

oni

ngt

hani

nnon-

f

unct

i

oni

ngt

eet

h,andi

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eas

oft

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hani

nar

easofcompr

essi

on 

.

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or

cescancausel

ocal

i

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osi

s(

cel

ldeat

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hel

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cut

t

i

ngof

ft

henor

malbl

oodsuppl

yt

ot

hecel

l

s.Thi

ssi

t

uat

i

oni

mmedi

at

el

yr

esul

t

si

n

st

oppageofr

emodel

i

ngatt

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f

ect

edsi

t

e.

 Ther

ef

or

e,or

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i

ct

oot

h

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snol

ongerpossi

bl

e.

 Repai

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svi

aemi

gr

at

i

onofcel

l

sfr

om

adj

oi

ni

ngvi

t

alper

i

odont

all

i

gament

.

 


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رفعت المحاضرة من قبل: Sultan Alsaffar
المشاهدات: لقد قام 9 أعضاء و 170 زائراً بقراءة هذه المحاضرة








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