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Parodoniul

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Histoarhitectonia proceselor alveolare

Histoarhitectonia ligamentului parodontal

Histoarhitectonia cementului Histoarhitectoniajonciunii dentogingivale

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Histoarhitectonia proceselor alveolare

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Generaliti

Arii/teritorii din maxilare/mandibule care formeaz/conin alveolele dentare, ncare sunt localizai i ancorai dinii (prin ataarea fibrelor ligamentuluiparodontal)se formeaz n paralel cu elongarea radicular, ca rezultat al acestui proces i alerupiei dentarentre osul maxilar/mandibular i procesele alveolare nu se poate trasa o limit de

demarcaiematurarea proceselor alveolare concomitent cu stabilirea dintelui n ocluziefuncionalntre procesele alveolare idiniexist o strnsinterdependen: dac dintele sepierde, procesele alveolare involueazi disparosul alveolar cel mai instabil component parodontal cu activitate metabolic

extrem de ridicatialternana proceselor de resorbiei formare

Procesele alveolare = os alveolar varietate de esut conjunctiv format dintr-o matriceextracelularicelule proprii matricea extracelular include o component organic i o component

anorganic

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Structura histologica proceselor alveolare

COMPONENTAORGANICalctuit din proteine fibroase (colagen tip I 90% i colagen tip V n cantitimici) plus alte macromolecule (glicozaminoglicani, proteoglicani,glicoproteine de adeziune)

Fibrele de colagen tip Idiferite de colagenul tip I din alte esuturi conjunctive permite legturamoleculelor prin puni de hidrogen rezistencrescutorganizarea primar, n reeanlocuit n osul matur printr-o dispunereordonat,spiralat, cu un grad de rsucire de la o lamel la altaGlicozaminoglicanii

lanuri polizaharidice lungi nesulfataiacidul hialuronic sulfatai:condroitinsulfat, keratansulfat formnd proteoglicani

Moleculele glicoproteice de adeziuneosteocalcina, osteonectina, osteopontina, trombospondina i sialoproteina

osoas

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COMPONENTA ANORGANIC

67% din masa uscat a matricei extracelulare

format n principal din cristale dehidroxiapatit

CELULELE ESUTULUI OSOS

tipuri celulare: celula osteoprogen, celula bordant,

osteoblastul, osteocitul, osteoclastul

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Organizare spaial

Trei elemente (os fascicular, spongioasa, placacortical) care realizeaz, din interior spre exterior,doustructuri:

osul alveolar propriu-zis osul alveolar de suport

osul fascicular i placa cortical joncioneaz lanivelul crestei alveolare, localizat la 1,5-2 mm sub

niveluljonciunii amelocementarecreastaalveolar - definiti ca marginea coronara proceselor alveolare; este rotunjit anterior iaproape plat n aria molarilor

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A, Cement; B, ligament periodontal ; C, placa cribriform; D,maduva hematogen n os spongios; E, os fascicular; F, osspongios

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Osul alveolar propriu-zis (lamina cribla, lamina

dura) corespunde zonei celei mai interne a procesului alveolar:

tapeteaz/limiteaz alveola = punctul de ataament alfasciculelor de fibre din ligamentul parodontal

origine n foliculul/sacul dentar coincide cu osul fascicular multiple perforaii (foramene) care conduc elemente

vasculare i nervoaseplaccribriform/lamina cribla

aspect intens radioopac (lamina dura) evaluarearadiologic este important n patologia periapical iperiodontal

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Osul alveolar de suport

reprezint corpul i limita extern aprocesului alveolar

include spongioasa i placa cortical

n aria diniloranteriori a ambelor maxilare,

osul de suport este subire- la acest nivelnu exist os spongios i placa corticalfuzioneaz cu osul fascicular

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Osul fascicular

osul care tapeteaz/limiteaz alveola = zona subire de os localizat celmai intern n alveol, punctul de ataament al fasciculelor de fibre din

ligamentul parodontaldenumire datorat structurii ifunciei legate de fibrele Sharpey

multiple perforaii cu elemente vasculare i nervoase = placcribriform/lamina cribla

aspect intens radioopaclamina dura

Morfologie:

fascicule de fibre osoase grosiere, mpletite aranjate n lamele subiri,paralel cu axul lung al peretelui alveolar

matricea osoas include i fibrele Sharpey care ptrund n os

perpendicular sau oblic, pe distane variabile i care sunt mineralizatedoar periferic, zona central nefiind mineralizat (ca n cementul celular)

Aici ele sunt mult mai mari comparativ cu cele care se inser n cement

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Osul spongioscomponent al osului de suport, localizat ntre osulfascicular (osul alveolar propriu-zis) i placacorticalos trabecular, care ocup mijlocul proceseloralveolare

Morfologie:os de membran, fibrilar, cu dispunere n lameleParticularitate:

prezenasistemelor Havers n mijlocul trabeculelormaritrabeculele delimiteaz ntre ele spaii areolare,coninndmduvosoashematogen

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Placa cortical

Formeaz zona de suprafa, respectiv placaextern (bucal) i intern (lingual) a proceseloralveolare

se extinde de la creasta alveolar, bucal sau labial,

spre limitele de jos ale alveolelorMorfologie:

os compact fin fibrilar

constituit din lamele longitudinale,circumfereniale, susinute de canale Havers,formnd sisteme haversiene de grosime variabil

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Procesul alveolar interdentar

ntre dou alveole adiacente

Centrul constituit din plcile corticalecorespunztoare, peste care se suprapune, de

ambele pri, osul fascicular care delimiteazinteriorul unei alveole i, respectiv, osul fascicular alceleilalte alveole

Osul spongios apare localizat mai apical, ocupndspaiul de o parte i de alta a plcilor corticale, ntreacestea i osul fascicular corespondent

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A sept interdentar, B ligament periodontal

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Componente structurale

MEC: Componenta anorganic: hidroxiapatita

Componenta organic: matrice amorf i fibrilar

Glicozaminoglicani Proteoglicani Glicoproteine de adeziune:

Osteocalcina

Osteonectina Osteopontina Trombospondina Sialoproteina osoas BMP

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Celule:

Ale esutului osos

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FUNCIILEPROCESELORALVEOLARE

se nscriu n cadrul general al funciilorparodoniului: protecie, susinere iataament pentru dinte

intervin n asigurarea hematopoiezei menin echilibrul mineral

realizeaz (prin vascularizaia i inervaia

proprie) condiiilor de pasaj pentruelementele nutritive, ctre celelaltecomponente ale parodoniului

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Histoarhitectonialigamentului parodontal

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A Dentina

B Cement

C Ligamentperiodontal

D Osteon

E Spaiu interstiial

F, G, Placa cribriform

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Structur

format din celule i matrice extracelular(conine substan fundamental (70% ap,glicozaminoglican n principaldermatansulfatul) i fibre

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FIBRELELIGAMENTARE

Fibrele:

colagen, tip I i tip III; fibrile cu diametru relativ mic (55 nm), ceea ce indic oasamblare fibrilar foarte rapid; organizare n fasciculeoxitalanelaunin

procesul de sintezi degradare a colagenului se desfoar extrem de rapidturnover-ul este mai ridicat n zona central i n extremitatea adiacentproceselor alveolare, dect n extremitatea adiacent cementuluiclasificarea fibrelor are la baz modalitatea de orientare,punctul deplecarei punctul de ancorare: grupul dentoalveolar, cruia i se adaug, fr aaparine direct ligamentului parodontal, un grup gingival

capetele terminale, denumite fibre Sharpey, sunt nglobate fie n cement, fien os

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Fibrele Sharpey tipuri: n tirbuon/spiralate (n cementul primar

acelular)

drepte (n cementul secundar celular i os) fibrele principalerealizeaz cea mai mare partea ligamentului organizate n fascicule bine ndefinite, distincte, vizibile n MO

fibrele principale sunt solidarizate prinintermediul a dou tipuri de fibre identificabiledoar n ME: fibrele indiferente i fibreleintermediare

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Grupul dentoalveolar - n raport cu localizarea,se descriu 5 grupuri diferite:- grupul crestei alveolare

- grupul orizontal- grupul oblic- grupul apical- grupul interradicular

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B - grupul

cresteialveolare

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A - grupul

orizontal

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A - grupul oblic

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A - grupulapical

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A - grupulinterradicular

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Fibrele de oxitalan

fibre elastice imature denumite fibreadiionale

formate din fascicule de microfibrile, aezateparalel

evideniate prin coloraii speciale

localizare preferenial: n jurul pereilorvasculari

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Fibrele de elaunin

constituite din fascicule de microfibrilenglobate ntr-o cantitate mic de elastin

aezate n reea alturi de fibrele de oxitalanplasextins de la cement la os, posibil cu rolde susinere pentru fasciculele de fibre de

colagen

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CELULELE REZIDENTE

1. Fibroblaste

2. Osteoblaste

3. Osteoclaste

4. Cementoblaste5. Resturi celulare epiteliale Malassez

6. Celule mezenchimale nedifereniate

7. Macrofage

8. Celule asociate cu structurile vasculare i nervoase

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CELULA MEZENCHIMAL

NEDIFERENIAT- localizat perivascular- funcie de celul progenitor

- ? o singur celul progenitor pentru celule-fiice(fibroblaste, osteoblaste, cementoblaste)-? mai multe celule progenitor, pentru fiecare

linie n parte

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FIBROBLASTELELIGAMENTARE

principala populaie celular a ligamentuluiparodontal

caracterizate de capacitatea realizrii unui

turnover cu rat extrem de nalt pentrucompartimentul extracelular, n particular pentrucolagen

rennoirea colagenului are loc de-a lungul ntregii

grosimi a ligamentului, i nu n teritorii limitate. MO: celul alungit, fuziform, cu citoplasm

abundenti nucleu oval

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ME: Bogate n organite celulare implicate n sinteza i

secreia proteic: RER, complex Golgi, vezicule desecreie

citoschelet foarte bine dezvoltat: actin, care susinetransformrile morfologice, precum i posibilitile dedeplasare

jonciuni intercelulare, de tip adherensigap

pe suprafa: n regiunile membranei celularedensificate zone de asociere ntre filamenteleintracelulare, filamentele extracelulare ifibronectin, numite fibronexus

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Grad mare de heterogenitate:

remodelarea fibrelor de colagen este realizatnumai de fibroblast care, simultan, este capabil desintez, sau de degradare a colagenului

dovezi experimentale: o singur celul poate ndeplini aceste funcii, fiind deopotriv fibroblastifibroclast

o terminaie a celulei este activ n asimilarea

lanurilor de procolagen, care vor forma apoisuperhelixul moleculei de colagen

cealalt terminaie este activ n fagocitareacolagenului, motiv pentru care conine un sistemlizozomal

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Resturi celulare

epiteliale Malassez

- din teaca Hertwig

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FUNCIILELIGAMENTULUIPARODONTAL

de susinere/de ataament - asigurancorarea/ataarea dintelui n alveola dentar,diminund aciunea forelor fizice externe;creeaz o legtur ntre cement i os

formativ - particip la formarea osului iresorbia osului, formarea cementului

nutritiv - prin vascularizaie

senzorial - rol n perceperea senzaiilor tactile ide presiune

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Histoarhitectonia cementului

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Generaliti

varietate de esut conjunctiv dur, mineralizat,localizat la nivel radicular, cu dispunere n straturiconcentrice n jurul dentinei

alturi de dentini os, aparineaceleiai familii

de esuturi conjunctive specializate, dure,specifice dintelui i are numeroase caracteristicicomune cu osul i dentina, fiind ns mai puinmineralizat dect acestea

mai gros n jurul apexului i n zona defurcaie a dinilor multiradiculari, comparativcu celelalte arii radiculare

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ACEL, acellularcementum

C, crown

CC, coronal cementum

CEL, cellular cementum

CVX, cervix

D, dentinE, enamel

R, root

RC, radicular cementum

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Jonciuni

jonciuneacementodentinar ondulat (uneori) n dentiia decidual,

neted,liniar n dentiiapermanent confer un ataament ferm al cementului de

dentin jonciuneaamelocementar

cementul i smalul se ntlnesc ntr-o

manier de contiguitate la nivel cervical limit de demarcaiedistinct,comparat cuo lam de cuitneted

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Jonciunea dentino -

cementar

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A, coronal cementumC, radicular cementumD, dentinE, enamel

GCT, gingival connective tissueHD, hemidesmosomesIBL, internal basal lamina

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Variante ale relaiei cementului cu smalul

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Morfologie

foarte apropiat de os, prin: prezena celulelor proprii (cementoblaste i

cementocite), localizate n lacune (cementoplaste)

depunerea incrementale, exprimat prin apariialiniilor de cretere

nu conine canale Havers i este completavascular i neinervat

Originean cea mai mare parte mezenchimal

studii recente certific o origine epitelial pentru

anumite teritorii ale cementului

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Structur

Dou componente: anorganic (45-50%) i

organic (50-55%)

componenta anorganic: fosfat tricalcic organizat n cristale de HA, cu

diferenefa de celelalte esuturi dentare dure

componenta organic:

n principal colagen tip Iiglicozaminoglicani caracteristici similare cu colagenul tip I i

glicozaminoglicanii existeni n celelalte varietide esut conjunctiv, specifice dintelui

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Tipuri de cement i funcionalitate

Variante diferite de clasificare, fapt explicabil prinoriginea, structura i funciile deosebite aletipurilor de cement

- elemente de difereniere:

1.Momentul formrii(primar/secundar);

2.Prezena/absena celulelor n matricea depus(celular/acelular);

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3.Originea fibrelor de colagen ale matricei (intrinseci proprii, rezultate prin sinteza cementoblastelor, extrinseciprovenite de la nivelul ligamentului parodontal i consecutivincorporate)

cement primar acelular fibrilar intrinsec

cement primar acelular fibrilar extrinsec

cement secundar celular fibrilar intrinsec cement secundar celular fibrilar mixt

cement acelular afibrilar

cement stratificat intermediar cement stratificat mixt

1 C l i l l fib il

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1. Cementul primar acelular fibrilarintrinsec

localizat imediat adiacent dentinei, grosime de 15-20 m primul element al parodoniului care apare, respectiv

primul cement depus, nainte de formarea ligamentului

parodontal format de cementoblaste care sintetizeaz colagenul din

matricea cementar deci fibrele sunt considerate intrinseci cementoblastele nu rmn incorporate n matrice

fibrele de colagen au o dispoziie paralel cu suprafaardcinii marginea extern = fibroas este zona de conectare a

fasciculelor de colagen provenite din ligamentul parodontal

2 C t l i l l fib il

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2. Cementul primar acelular fibrilarextrinsec

apare imediat dup formarea variantei fibrilare intrinseci,care este baza sa de depunere

acoper cele dou treimi ale rdcinii este extinsi adesea este singurul tip de cement prezent

formare: prin mineralizarea progresiv a fibrelor de colagen provenite dinligamentul parodontal, inserate anterior n marginea fibroas acementului primar acelular fibrilar intrinsec (ME)

aceste fibre de colagen sunt denumite fibre Sharpey

procesul de mineralizare se deruleaz prin depunereasubstanelor anorganice de jur-mprejurul i printre acestefibre

dispunerea fibrelor Sharpey este perpendicular pe fibrele decolagen intrinseci

3 C t l d l l

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3. Cementul secundar celularfibrilar intrinsec

localizat limitat, n regiunile apicale iinterradiculare ale dinilor

aproape ntotdeauna absent n incisivi i canini momentul elaborrii anterior formrii

ligamentului parodontal celule responsabile: cementoblaste diferite

fenotipic de cementoblastele care depuncementul primar acelular, dar similareosteoblastelor

cementoblaste rmn sechestrate n lacune, nmatricea organic, care apoi se mineralizeaz

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4. Cementul secundar celular fibrilar mixt

localizat n treimea apical a rdcinii, apexul putnd fi formatcomplet din cement celular

funcieadaptativ deci are dimensiuni idistribuie inconstante

momentul elaborrii tardiv, dup definitivarea ligamentuluiparodontal sau, uneori, chiar duperupiadentar

Formare:

prin depunerea de cement celular i, concomitent, incorporarean matricea acestuia a fasciculelor de fibre de colagen cu originen ligamentul parodontal

Organizare stratificat lamelar lamelele sunt diferite comparativ cu cele ale cementului primar:

mai larg spaiate, mai distanate, indicnd o rat de formare multmai rapid

conine celule i fibre

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4. Cementul secundar celular fibrilar mixt

Structur celule: cementocite (celule adulte)

situate n lacune i dispuse aleator, dispersat

corp celular ovalar sau poligonal

prelungiri ramificate, radiare, predominantorientate spre PL, situate n canaliculi, seanastomozeaz ntre ele i stabilesc comunicaiichiar cu celulele LP (prin jonciuni gap), dar nurealizeaz un ansamblu sinciional, ca n os

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fibre de colagen intrinseci dispuse paralel cu axul radicular

fine, dens mpachetate

mineralizare uniform

fibre de colagen extrinseci (Sharpey) Perpendiculare pe axul rdcinii

mari, aranjate la ntmplare, ptrund adnc i seramific n matrice

mineralizare neomogen, au miez necalcificat i zonperiferic intens mineralizat

unele penetreaz profund n interiorul stratului decement

4. Cementul secundar celular fibrilar mixt

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5. Cementul acelular afibrilar

localizat n apropiereajonciunii amelocementare

nu are rol de ataare

apare ca o anomalie de dezvoltare, n urma unei

rupturi a epiteliului redus al organului smalului

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6. Cementul stratificat mixt

localizat la nivelul apexului

formparticular de cement: aranjament concentric, n straturi, de cement celular fibrilar intrinsec i

cement acelular fibrilar extrinsec

7 Stratul hialin Hopewell-Smith

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7. Stratul hialin Hopewell-SmithCementul epitelial

Date recente indic existena unui cement fr rol de ataament, localizat ntre

dentini cementul propriu-zis, cu apariie precoce n cementogenezStructur

conine un amestec de produi de sintez ai celulelor ectomezenchimale iepiteliale

are aspectul unui strat amorf, noncolagenic, atubular (lipsit de prelungiriodontoblastice)

prezint proteine asemntoare cu proteinele smalului

are un nalt grad de mineralizare (mai mare dect al dentinei i cementului)

IPOTEZE ASUPRA ORIGINII diferite, datoritcompoziiei sale particulare:

ncadrat ca un tip special de dentinconsiderat ca un esut propriu-zis, incomplet descifrat, prezentat n literatur subdenumirea de stratul hialin Hopewell-Smith

ncadrat ca cement epitelial datorit structurii care include proteineasemntoare cu proteinele smalului

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A- cement acelular B-stratul hialin

C- stratul granular Tomes din dentina D-dentina

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A- cement acelularB- cement celular

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B - Cement celular

A - Cement acelular

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Cementoblaste

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Cementocite

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A, Periodontal ligament

fibers;B, Sharpey's fibers;C, Dentino-cementumjunction;

D, Cementoblasts;E, Acellular cementum

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FUNCIILE CEMENTULUI

implicare n ataamentul dintelui

adaptare la modificrile determinate prin

micrilei uzura dintelui

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Histoarhitectoniajonciuniidentogingivale

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A, Sulcular epithelium; B,Junctional epithelium

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CT, gingival connective tissue

ES, enamel space

JE, junctional epitheliumOE, oral epitheliumSE, sulcular epithelium

EPITELIUL SULCULAR

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EPITELIUL SULCULAR Tapeteaz sulcusul gingival, constituind peretele moale al

acestuia Orientat cu faa spre dinte, frns a fi ataat de smal

Se ntinde de la rebordul marginal gingival pn laepiteliul dejonciune

HISTOLOGIC

epiteliu stratificat pavimentos nekeratinizat subire

ME: RER slab reprezentat, numeroase tonofilamente

membrana bazal de susinere este rectilinie, lipsindcrestele epiteliale

absena keratinizrii datorat, cel mai probabil,inflamaiei permanente a esutului conjunctiv subjacent

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CT, connective tissue GS, gingival sulcus PKE, parakeratotic epithelium

EPITELIUL JONCIONAL

http://window.close%28%29/http://window.close%28%29/http://window.close%28%29/http://window.close%28%29/http://window.close%28%29/

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EPITELIUL JONCIONAL- formunic de epiteliu

- formeaz un guler n jurul regiunii cervicale a dintelui, este ncontact cu suprafaa mineralizat a dintelui, adiacent suprafeeismalului, de la jonciunea amelocementar, extinzndu-secoronar, pe o distan de 2-3 mm, pn la baza sulcusului gingival

- HISTOLOGIC: epiteliu stratificat , subire

- form triunghiular/ evantai: zon mai larg la baza sulcusuluigingival (15-30 rnduri de celule suprapuse) izonngust apical,corespunztoarejonciunii amelocementare (3-4 celule)

- particularitatea structural unic: limitat de dou membranebazale rectilinii, diferite structural:

- o membran bazal extern, care l separ de esutulconjunctiv subjacent;- o membran bazal intern, ataat de dinte, produs

exclusiv de celulele epiteliale

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Junctional epitheliumCT, connective tissueES, enamel spaceJE, junctional epithelium

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CT, connective tissue; EBL, external basal lamina; ES, enamel space; IBL,internal basal lamina; JE, junctional epithelium

EPITELIUL JONCIONAL

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EPITELIUL JONCIONALMembrana bazalintern

- format numai din lamina lucida i lamina densa- lipsa colagenului tip IV- fibrile desprinse din celulele epiteliale de suprafa

penetreaz lamina lucida i lamina densa, pentru a

facilita ataamentul la suprafaa dintelui- ancorarea real - prin intermediul hemidesmozomilor- celulele epiteliale de suprafa funcioneaz

asemntor cu celulele bazale: secret o membran

bazal-like, sau o substancuticular, peste care sepot aduga glicoproteine salivare i depozitebacteriene

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EPITELIUL JONCIONALStraturi celulare: stratul bazal i stratul suprabazal

1. Stratul bazal- ancorat prin hemidesmozomi de membrana bazal

extern- format din celule cuboidale sau ovalare, cu activitate

mitoticintens2. Stratul suprabazal

- iniial: celule cu iniial un aspect stelat, cu conturneregulat- treptat: caracter pavimentos turtite, aplatizate, cu

dispoziieparalel cu suprafaa dintelui

EPITELIUL JONCIONAL

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EPITELIUL JONCIONALME:

elemente care difer de cele prezente n celulele epiteliuluigingival din alte teritorii:

cantitatea de RER i de complex Golgi este mai mare

prezente mai puine tonofilamente;

exist lizozomi primari, fagolizozomi, vezicule electronclare careconin structuri rotunde sau vezicule ovalare, electrondense

puini desmozomi, mai frecvent gap ijonciuni strnse

Caracteristicile morfologice: epiteliu nedifereniat imatur (prin IHCs-au analizat keratinele n citoplasma celular i carbohidraiiexisteni pe suprafaacelular)

Diagrama indic drumul celulelor

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Diagrama indic drumul celulelori fluidelor ntre sulcus i esutulconjunctiv gingival

CT, connective tissueJE,junctional epitheliumOE, oral epitheliumS, gingival sulcusSE, sulcular epithelium

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EPITELIUL JONCIONAL

turnover-ul epiteliuluijoncionalrat foartenalt 6zile

suprafaa epitelial nu este disponibil pentrueliminarea celulelor astfel c celulele ascensioneaz

spre suprafaa dintelui pn la aproximativ dou-treistraturi de celule distan fa de membrana bazalintern i respectiv smal i se deplaseaz n direciecoronar,paralel cu suprafa dintelui; exfolierea are

loc n sulcus celulele superficiale, continuu nlocuite menin

ataarea cu suprafaa dintelui; ataarea este dinamic,fiind formai noi hemidesmozomi

ESUTUL CONJUNCTIV SUBJACENT EPITELIULUI

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ESUTUL CONJUNCTIV SUBJACENT EPITELIULUISULCULAR I EPITELIULUI JONCIONAL

exist expresii fenotipice diferite ale esutului conjunctiv subjacentepiteliului sulcular i, respectiv, epiteliuluijoncional

Epiteliul sulcular

esut conjunctiv asemntor celui din corionul epiteliului gingival oral, are

capaciti instructive ce influeneaz maturarea epitelialEpiteliuljoncional - caracter imatur!

esut conjunctiv mai profund, n legtur cu ligamentul parodontal;conine numai factori permisivi, implicai n meninerea epiteliului, nu in maturare; formeaz hemidesmozomi la contactul cu suprafaa dintelui

Diferenele structurale importante pentru elucidarea mecanismelor carestau la baza instalrii bolii parodontale i pentru instituirea unor proceduristomatologice de regenerare ajonciunii dentogingivale

ESUTUL CONJUNCTIV SUBJACENT EPITELIULUI

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ESUTUL CONJUNCTIV SUBJACENT EPITELIULUISULCULAR I EPITELIULUI JONCIONAL

trsturmorfologicparticular (raport cu lamina propria gingival) deunde prezena unei populaii de celule inflamatorii, chiar n condiiifiziologice

instalarea unui anumit grad de inflamaie este un element aproapenormal la nivelul jonciunii dentogingivale chiar din momentul erupiei

dentarePrezena infiltratului inflamator subjacent epiteliului sulcular asociat cu

dobndirea caracterului epitelial nekeratinizat la acest nivel(experimente animale cu regim strict de igienorali antibiotice duc lakeratinizare)

Concluzia: procesul inflamator este responsabil de transformarea unuimodel de maturaie n altul, prin deprimarea unei trsturi morfologice

Odat cu naintarea n vrst scade nivelul inflamaieiesutului conjunctivi apare o deplasare lent a zonei de ataament, proces denumit

incorect erupiepasiv

Rolul jonciunii dentogingivale n meninerea

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Rolul jonciunii dentogingivale n meninereaintegritii parodoniului

acioneaz pentru a proteja cementul, ligamentul parodontal iosul alveolar de factorii agresivi dezvoltai n cavitatea oral Dac procesul inflamator depete un anumit grad de

proliferare activ la nivelul epiteliului joncional apare migrareaepiteliuluijoncional cu formarea unei pungi parodontale

deteriorarea i pierderea atarii epiteliale duce la adncireasulcusului gingival elemente care definesc patologiaparodontal

Factori determinanidiveri: inflamaie accentuat a celulelor epiteliale superficiale, de

ataament sau a esutului conjunctiv subjacent rspuns imun la antigeni bacterieni iritaiemecanicdatorat instrumentarului, agresiunii exercitate

de alimente, formrii de plac sau calculi

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