Stojanovićisar./ekstrakCiOna rana kOd PaCOVaActaStomatologicaNaissi

INFORMATIVNI RAD INFORMATIVE ARTICLE

Jun/June2011,vol.27,br./num.63str./p1067-1076

ZARASTANJE EKSTRAKCIONE RANE NA EKSPERIMENTALNOM MODELU PACOVA

HEALING OF EXTRACTION WOUNDS IN AN EXPERIMENTAL MODEL OF RAT

Simona Stojanović, Milan Spasić, Miloš Tijanić

*uniVerzitet u niŠu, MediCinski Fakultet, klinika za stOMatOlOGiju Odeljenje Oralne hirurGije

uniVersitY OF niŠ, MediCal FaCultY and CliniC OF stOMatOlOGY, dePartMent OF Orl surGerY

ABSTRACT Uvod: Proces zarastanja rane nakon ekstrakcije zuba je sa velikom pažnjom istraživan kod nekoliko životinjskih vrsta pod normalnim i eksperimentalnim uslovima koji bi mogli ometati zarastanje. Hro­nologija zarastanja rane nakon ekstrakcije zuba – molara i inciziva se kod pacova odvija u nekoliko faza i ispitivana je histološkim, radiograf­skim, dezintrometrijskim, imunohistohemijskim i stereološkim(tačkasta volumetrija) metodama, kao i upotrebom mini kamere za određivanje volumenske frakcije histoloških komponenti Cilj rada: Na osnovu literature dostupne u elektronskim bazama po­dataka analizirati histolo-ške i radioloske rezultate o toku zarastanja normalne ekstrakcione rane pacova i vremenskog perioda koji je po­terban da rana nakon eksrakcije u potpunosti zaraste. Materijal i metod: Istraživanjem smo dobili 22 rada koji prate norma-lan tok zarastanja od kojih je 7 zadovoljilo kriterijume pogledu kom­pletnog opisa događaja u alveoli nakon ekstrakcije zuba kod pacova. Rezultati: Drugog dana nakon ekstrakcije rana pocinje da epitelizira. Prvi znaci stvaranja koštanog tkiva javljaju se četvrtog dana posle eks­trakcije kao subperiostalna osteogeneza. Četvrtog i petog dana, kod nekih fibroblasta počinje diferencijacija u osteoblaste. Petog dana vide se delikatne trabekule mlade kosti i rtg prisutna jača senka u ce­tralnom delu apikalne trećine alveole. Zavrsetak epitelizacije je osmog dana posle ekstrakcije kada je lamina dura malo manje izražena, dok donji delovi alveole imaju izraženiju rtg senku. Četrnaestog dana u najvećem broju primeraka, alveola je potpuno popunjena retikularnom kosti cija je rtg senka približna okolnoj kosti. Dvadesetog dana mla-da kost ispunjava alveolu. Šezdesetog postoperativnog dana alveolu ispunjava lamelarna kost, dok se remodelacija koštanih rubova nastav­lja do 112. postoperativnog dana. Zaključak: Zarastanje ekstrakcione rane kod eksperimentalnih pacova počinje sa pojavom epitela drugog dana posle ekstrakcije. Koštano tkivo počinje da se stvara četvrtog dana posle ektrakcije. Završetak epitelizacije je 8. dana, dok mlada kost ispunjava alveolu 20. post­operativnog dana. Potpuno koštano zarastanje dešava se 60. dana posle ekstrakcije. Metode od kojih je očekivano da ubrzaju zarastanje ekstrakcione rane kao što je primena lasera male snage, koštanog mor­fogenetskog proteina i polarizovane svetlosti na modelu pacova nisu dale očekivane rezultate.

Ključne reči: ekstrakciona rana, zarastanje, eksperimentalne životinje

ABSTRACT Introduction:The process of wound healing after tooth extraction has been studied in several animal species under normal and experimental conditions that might interfere with the healing. Chronology of wound healing after tooth extraction (molars and incisors), which consists in several phases, has been examined by histological, radiological, im­munohistochemistry, stereology (bone volumetry), and densitometry methods and by using of micro-camera to determine the volume frac­tion of histological components. The aim of this study is to analyse the process of healing of normal extraction wound and to determine the period of time it takes for the postextraction wound to completely heal. Matherial and method: The research is based on the literature avail­able in electronic databases Pubmed/Medline, Kobson, Googlescholar. The total of 22 papers which follow the normal course of healing were found; 7 papers met the criteria regarding the complete description of the healig process in the socket after tooth extraction in rats. Results: On the second day after the extraction wound starts with form­ing epithelium. The first sign of bone tissue has appeared four days af­ter the extraction as subperiostal osteogenesis. On fourth and fifth day, in some fibroblasts differentiation in osteoblasts has already begun.. On the fifth day the delicate trabecules of young bone attached to the walls of the socket in its basal part can be seen, and the signs of ossifi­cation are clearly indicated by a darker shadow in the central part of the apical third of the socket present in the x ray. The end of the epitel­ization is on the eighth day, when the lamina dura was slightly less pro­nounced, while the lower parts of the socket have a pronounced X-ray shadow. In most of the specimens, the socket has been completely filled with reticular bone on day 14. The socket has been filled with young bone after 20 days.Presense of lamelar bone can be seen 60th day after exraction. Remodelation of aveolar ridges lasts until 112th day. Conclusion: The healing of normal extraction wounds in rats begins with the appearance of the epithelium of the second postoperative day, and the end of the epitelization is on the eighth day . Formation of bone begins on the fourth day after the exodontia. The intense bone forma­tion lasts until the twentieth postoperative day when the young r bone fills the socket. Lamellar bone is present on 60th days after extraction. Applicaton of bone morfogenetic protein, low power laser and polar­ized light had no expected effect on the the healing of the extraction wound in experimental rats.

Key words: extraction wound, healing, experimental animal

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UvodProces zarastanja rane nakon ekstrakcije

zuba je sa velikom pažnjom istraživan kodnekoliko životinjskih vrsta pod normalnimi eksperimentalnim uslovima koji bi mogliometatizarastanje.

Pacoviimajuukupnošesnaestzuba,osamugornjojiosamudonjojvilici1.Odtogačetiriduga,ostrainciziva,podvausvakojvilici.In-cizivisuspecijaliovanizaglodanjeimoguseobnavljati tj. ponovo izrastati tokom zivota.Imajujedan,dugkorensaširokimapikalnimotvorom.Kadabiizrastalibeztrošenja-abrazije,incizivibibililučnosavijenipoduglomod86stepeni.Stopaerupcije jekododraslihpacova2,2mmnedeljno(0,31-0,32mmdnevno),donjiinciziviuprosekurastu2,8mmnedeljno(0,4mmdnevno).Na taj način stari zub se zame-ninovimzanekih40-50dana,odnosnopacovnemaincizivastarijihod50dana1.

Molarikodpacovasluzezamlevenjehrane.Postojiukupnodvanaestmolara,pošestusva-kojvilici, sasvakestranepo tri.Molari seneobnavljaju, tj. kod pacova postoji samo jedansetmolarautokuživota,zbogtogasenaziva-jumonofiodonti.Molariimajudvamalokraćakorena,kojinerastu1.

Pacovi nemaju ni očnjake ni premolare.Na mestima gde bi trebalo da budu lateralnisekutići, očnjaci i premolari postoje prostranedijasteme.

Broj i vrsta zuba kod različitih vrstaizražavajusekaodentalnaformula.In/nCn/nPn/nMn/n,gdejeI,C,P,Moznakazaincizive,kaninuse,premolareimolare,dokjen/n-odnosgornjiidonjihzubasasvakestaneuvilici.Takodolazimododentalneformulekodpacovakojaglasi:I:1-1,C:0-0,P:0-0,M:3-32.

Hronologijazarastanjaranenakonekstrak-cijezuba–molaraiincizivakojasekodpacova

Introduction

The process of wound healing after toothextractionhasbeen studiedwithgreat care inseveral animal species under normal and ex-perimentalconditionsthatmightinterferewiththehealing.

Rats have a sixteen teeth, eight in the up-pereightinthelowerjaw1.Therearefourlong,sharp incisors, two in each jaw. Incisors arespecializedforgnowingandcanberenewed,i.e,theycontiniuegrowingthroughoutlife.In-cisorshavealongrootwithawideapicalopen-ing. If grown without abrasion, incisors archwould form an angle of 86 degrees.The rateoferuptioninadultratis2.2mmperweekforupperincisors(0.31to0.32mmperday),withaverage 2.8 mm per week for lower incisors(0.4mmper day).Rats naveno incisor olderthan50days,causetheoldtoothisreplacedbyanewinapproximately40-50days1.

Ratmolarsareusedforgrinding.Thereareatotaloftwelvemolars,sixineachjawthreeon each side.Molars don’t get renewed, thatis in rats there is only one set ofmolars in alifetime,whichiswhytheyarecolledmonofi-odonts.Molarshavetworootsthatarealittleshorterandtheydonotgrow1.

Ratshavenocaninesorpremolars.Thereislargediastemainplaceswherethereshouldbelateral incisors,caninesandpremolars. Indif-ferentspeciesthenumberandtypeofteethareexpressedasadentalformula.In/nCn/nPn/nMn/n,whereI,C,P,Maresignifyin-cisors,caninuses,premolarsandmolars,whilen/n-isratiobetweentheupperandlowerteethoneachsideinthejaw.Thedentalformulainratis:I:1-1,C:0-0,P:0-0,M:3-32.

Woundhealingchronologyaftertoothex-traction (molars and incisors), which consistsinseveralphases,hasbeenexaminedbyhisto-logical, radiological, immunohistochemistry5,6 stereology (bone volumetry), and densitome-try3,4,methodsandbyusingofmicro-cameratodeterminethevolumefractionofhistologicalcomponents7.

The aimofthisstudyistoanalysethepro-cessofhealingofnormalextractionwoundandtodeterminetheperiodoftimeittakesforthepostextraction wound to completelyheal3–7.The research is based on the literature avail-ableinelectronicdatabasesPubmed/Medline8, Kobson9,Googlescholar10.The studieswhich

Slika 1. Vilice pacova1

Figure1. A jaws in rats1

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odvijaunekolikofazaispitivanajehistološkim,radiografskim,dezintrometrijskim3,4,imunohi-stohemijskim5,6 i stereološkim (tačkasta volu-metrija) metodama, kao i upotrebom mini kamere za određivanje volumenske frakcijehistološkihkomponenti7.

Cilj radajedanaosnovuliteraturedostupneu elektronskim bazama podataka Pubmed/Medline8, Kobson9, Googlescholar10 anal-iziramorezultateotokuzarastanjanormalneekstrakcioneraneivremenskogperiodakojijepoterbandarananakoneksrakcijeupotpunostizaraste3–7.Nisurazmatraniradoviukojimasuobrađivani eksperimentalni modeli kod kojihje aplikovan analgetik, antibiotik, hormonskasupstanca, idrugimedikamenti,kaoionikodkojih su odstranjene polne žlezde, pankreas,druga tkiva ili organi, kod kojih je namernopravljendefektukostivilicainakontogaprćentokzarastanjarane.

RezultatiIstraživanjemsmodobili22radakojiprate

normalan tok zarastanja od kojih je 7 zado-voljilokriterijumeu pogledukompletnogopisadogađajaualveolinakonekstrakcijezubakodpacova.

Histološka analiza ekstarkcione rane4,6,11

U studijama su uglavnom žrtvovani Wi-starpacovikoji sučuvanipod istimuslovimaižrtvovaninaistinačin.Intraperitonealnomin-jekcijompacovisuuvedeniuopštuanesteziju,dabiimzatimbilipažljivoekstrahovanizubi.Pacovi su žrtvovoani dekapitacijom, vilice supotapaneu10%rastvorformalinana48sati.Posle fiksacije vilice su tangencijalno presec-aneipotapaneuparafin.Longitudinalnipresecidebljine po 6nm bojeni su hematoksilinom ieozinom.

1.dan:Alveoluispunjavakoagulumkojisesastojiodmešavinefibrinaićelijakrvi.Ćelijeperiodontalnogligamentasudominantnećelijeu alveoli. Proliferacija ćelija je niska (in-deksprebojenostiL=oko2%)do16hnakonekstrakcijezuba,alidramatičnorastenamaksi-malninivo1danposleekstrakcije(L=23%)4. Između1i2dana,brojnifibroblastikojipotičuiz ostatka periodontalnog ligamenta aktivnonaseljavajukoagulum inastavjajudasedase

usedexperimentalmodelswiththeapplicationofanalgetics,antibiotics,hormonalsubstancesandotherdrugs,aswellasthoseinwhichgeni-talglands,pancreatic, andother tissuesoror-ganswereremoved,orinwhichthedefectwasdeliberatelycaused intothejawboneinorderforthehealingprocesstobeobserved,havenotbeenconsideredinthisstudy.

ResultsThetotalof22paperswhichfollowthenor-

malcourseofhealingwerefound;7papersmetthecriteriaregardingthecompletedescriptionof thehealigprocess in the socket after toothextractioninrats.

Histological analysis of exraction wound 4,6,11

Wistar rats used in this studieswerekeptunderthesameconditionsandsacrificedinthesameway.General anesthesiawas administe-redtoratsbyinraperitonealinjection,andthentheteethwerecarefullyextracted.Theratsweresacrefitedbydecapitation, the jawswere sub-mergedinto10%formalinfor48hours.Afterthe fixation, jaws were tangentially sectionedand submerged in paraffin. Longitudinal sec-tions6nmthickwerestainedwithhematoxylinandeosin.

Day1.Thesocketisfilledwithmashofclotconsistingofamixtureoffibrinandbloodcells.Cellsofperiodontalligamentarethedominantcellsinthesocket.Upuntil16haftertoothex-tractioncellproliferationwaslow(indexofcol-oration(L)=2%),butincreasesdramaticallytothemaximumlevelonedayafterextraction(L=23%)4.Between1st and 2nddays,numerousfibroblastsderivedfromtherestofperiodontalligamentactivelypopulatetheclotandmulti-ply.Fibroblastspossessahighproliferativeac-tivity,butasmallnumberofcellularorganellesresponsibleforsynthesisofprocollagen,whichprovesthattreyaremostlyimmaturecells6.

Day 2. Blood clot surface is covered bythenecroticcontentconsistingofdegeneratedblood cells, fibrin and food debris, and thereisepithelialmigrationwhithinwhichthereareglycogengranulesmadevisiblebyPASstain-ing4.Therestoftheperiodontalligamentwasevident2daysafterextractionandrichintypeIIIcollagenfibers,whichcanformatemplate

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umnožavaju.Fibroblastiposedujuvisokupro-liferativnuaktivnost,aliimajumalibrojmobil-nih organela odgovornih za sintezu prokola-gena,takodasutouglavnomnezrelećelije6.

2. dan: Površina koaguluma pokrivena jenekrotičnim sadržajem koji se sastoji od de-generisanih krvnih ćelija, fibrina i debrisa odhrane,kaoiprisustvoepitelnemigracijeunutarkoje postoje granule glikogena uočljive PASbojenjem4. Ostatak periodontalnog ligamentaje evidentan2dananakon ekstrakcije i bogatkolagenimvlaknimatipaIIIkojamoguformi-rati šablon za stvaranje buduće trabekularnekosti11.Uostatkualveolepostojigeneralizova-nobojenjefibronektinaštoukazujenanjegovuvažnuuloguuformiranjugranulacionogtkiva,takoštostvaramatricuzamigracijufibroblasta.U apikalnom regionu alveole mezenhimalnećelijeprožimajukoagulum,doksenazidovimaalveole uočava nekoliko multinukleusnih gi-gantskihćelija.

3. dan: Fibroblasti sadrže višemobilnihorganela i deponuju više kolagenih vlakanakoja zamenjuju koagulum gustim vezivnomtkivom.Razvilisuseifibroblastiizendoseal-nogiperivaskularnogtkiva,alinanižemnivouiukasnijimvremenskomperioduodfibroblas-taizperiodontalnogligamenta6.Enosealniipe-rivaskularnifibroblastisusamoumalombrojuposlužilizadaljiproceszarastanjarane.

4. dan:Prvi znaci stvaranjakoštanog tki-vapočinjukaosubperiostalnaosteogeneza,sapojavomosteoidanaeksternojpovršinibukal-ne i lingvalne lamele (ekstraalveolarna apozi-cijakosti),kaoiosteoklastnaaktivnostkojajedoveladoresorpcijebukalnogilingvalnogal-veolarnogruba.Koagulumjepotpunozamen-jen gustim vezivnim tkivom, a zidovi alveolepokrivenisugigantskimćelijama.Epitelizacijagingivejeprogresivna,alinijeprekrilapovrši-nualveole.Četvrtogipetogdana,kodnekihfi-broblastapočinjediferencijacijauosteoblaste,aproliferacijafibroblastajedrastičnosmanje-nanabazalnevrednosti6.

5.dan:Alveolajevećimdelomprekrivenagingivalnimepitelom.Videsedelikatnetrabe-kulemladekostiprikačene zazidovealveoleu njenom bazalnom delu. Ostaci periodontal-ne membrane naziru se u tragovima, vlaknapočinju da gube svoju normalnu orijentaciju.Aktivnost osteoklasta (početak remodelacije)jeizraženanarubovimaalveole4,6.

8. dan:U ovomperiodu gingivalni epitelupotpunostipokriopovršinualveoleaapikalnideoispunjenjemladomkostiiosteoidom.Pe-riodontalniligamentnijevišeprisutan.Nastav-

forcreatingfuturetrabecularbone11.Intherestofthesocketthereisageneralizedstainingoffibronectinsuggestingitsimportantroleintheformation of granulation tissue, by creating amatrixformigrationoffibroblasts.Intheapi-calregionofthesocketthemesenchymalcellspenetrate the socket clot,while severalmulti-nucleusgiantcellscanbeobservedonthewallsofsocket.

Day3.Fibroblastscontain severalmobileorganellesanddepositmorecollagenfibersthatreplace theblood clotwith dense connectivetissue.Fibroblasts fromendoseal andperivas-culavar tissue have also developed, but at alowerlevelandlaterthanfibroblastsfromperi-odontal ligament6. Endoseal and perivascularfibroblastshaveplayedonlyaminerroletothefurtherprocessofwoundhealing.

Day4.Thefirstsignofboneformationissubperiostalosteogenesis,withtheappearanceofosteoidontheexternalsurfaceofthebuccaland lingual lamel (extraalveolar apposition ofbone)andosteoclastactivityleadingtoresorp-tion of the buccal and lingual alveolar edge.Theclothasbeentotallyreplacedbydensecon-nective tissue, and alveolarwalls are coveredwithgiantcells.Epitelizationofthegumsisaprogressive,buthasntstillcoveredthewholesurfaceofthesocket.Duringthefourthandthefifthday, insomefibroblastsdifferentiationinosteoblasts has already begun, and fibroblastproliferation was drastically reduced to basalvalues6.

Day 5. The socket is largely covered bygingivalepithelium.Thedelicatetrabeculesofyoungboneattachedtothewallsofthesocketinitsbasalpartcanbeseen.Remnantsofperi-odontalligamentcanbeobservedinthetrace,thefibersbegintolosetheirnormalorientation.Osteoclastsactivity(thebeginningofremodel-ing)isemphasisedattheedgesofthesocket4,6.

Day8.Atthispointgingivalepitheliumhascompletely covered the surface of the socketwhiletheapicalpartisfilledwithyoungboneandosteoid.Periodontalligamentisnolongerpresent. Depositionofbonecontinueson thebuccalandlingualsurfacessodoesresorptionandremodelingofboneedges.

Day10.Inmostofthespecimensthesockethasbeenhalffilledwithyoungbone.Thealve-olaredgesarerounded,partiallyduetoresorp-tion of the lingual and buccal sides, partiallybecausesubperiostalapposition.

Day13.Thintrabeculesofyoungboneoc-cupiedmost of the socket,while the alveolar

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ljasedepozicijakostinabukalnojilingvalnojpovršinikaoiremodelovanjerubovaresorpci-jom.

10. dan:U najvećem broju primeraka al-veolajedopolovinepopunjenamladomkosti.Rubovi alveole su zaobljeni, delimično usledresorpcijesa lingvalne ibukalnestrane, deli-mičnozbogsubperiostalneapozicije.

13.dan:tanke,trabekulemladekostizauze-le su veći deo alveole, dok se remodelovanjealveolarnog grebena i dalje nastavlja. Dobrokeratiniziraniepitelpokrivapovršinualveoleucelosti.Kolagenavlaknasuparalelenasaepi-telnombazalnommembranom4.

14. dan: U najvećem broju primeraka, al-veola je potpuno popunjena retikularnom ko-sti.Trabekularnapovršinapokazujeintenzivnukoštanuaktivnost.Ranajeupotpunostiepiteli-zirala3.

20.dan:Mladakostjeispunilaalveolu.Os-teoblasti prekrivaju površinske trabekule, alinema korteksa na gornjoj površini kosti. Pe-riost je u potpunosti regenerisan4. Tridesetogdanaodekstrakcijeaktivniosteoblastivideseuglavnomnaalveolarnomrubu.

60.dan:Alveoluispunjavalamelarnakost.Kostpokazujeskorohomogenikontinuitetigo-tovosenerazlikujeodsusednekosti4.

Nakon ekstrakcije inciziva proces zara-stanjaseodvijasenasličannačikaokodmola-ra.Uprvojnedeljidelikatnekoštanetrabekuleprekriveneosteoblastimasuvidljiveuglavnomuapikalnomisrednjemregionu,naunutrašnjojpovršinibukalnogzida.Postojiobiljevezivnogtkivainovoformiranihkapilara.Ostacikoagu-lumavideseucentralnimregoinima.Dokrajadrugenedeljedošlo jedoprogresivnogkošta-nogzarastanja,pričemujealveolajednakopo-punjenazrelimvezivnimtkivomikoštanimtra-bekulama.Utrećojnedeljiunutrašnjostalveolejepopunjenatrabekularnomkosti4.

Radiološka analiza ekstrakcione rane3,4

1.-4.dan:nartgsnimkuvidiserasvetljenjenamestunekadašnjihkorenova,laminadurasevidikaojasnodefinisananeprozirnalinija.

5.dan:jasnosevideprviznacipočetkaosi-fikacije - rentgenološkiprisutna jača senkaucetralnom delu apikalne trećine alveole.Ovajnalaz je u saglasnosti sa histološkimnalazomiz togperioida, odnosno sa pojavomkoštanihtrabekulauzzidovealveole.

ridge remodeling continues. Well-ceratinisedepitheliumcompletelycoversthealveolarsur-face.Collagenfibersareparallelwiththeepi-thelialbasalmembrana4.

Day14.Inmostofthespecimens,thesockethasbeencompletelyfilledwithreticularbone.Trabecular bone surface shows an intensiveboneactivity.Thewoundhasbeencompletelycoveredwithepithelium3.

Day 20. The socket has been filled withyoung bone. Osteoblasts cover the surface oftrabeculae,butnocortexontheuppersurfaceoftheboneexists.Periosteumiscompletelyre-generated4.30thdayaftertheextractiontheac-tiveosteoblastsaremainlyseenonthealveolaredge.

Day 60. The socket consists of lamellarbone.Thebone showsanearlyhomogeneouscontinuityandisalmostindistinguishablefromthesoroundingbone4.

After theextractionof incisors thehealingprocessgoesoninasimilarwayaswithmolars.In the firstweek delicate trabeculas of thebonecoveredinosteoblastsarevisiblemainlyin the apical andmiddle region, on the innersurface of the buccalwall.There is an abun-dance of connective tissue and newly formedcapillaries. The remains of blood clot can beseen in the central regions.By the endof thesecondweek the bone has heal progressively,andthesocketisequallyfilledwithmaturecon-nectivetissueandbonetrabeculas.Inthethirdweek the inside of the socket has been filledwithtrabecularbone4.

Radiographic analysis of the extraction wound3.4

Day 1-4: X-rays shows the illuminationwhere once therewere roots, lamina dura isseenasaclearlydefinedopaqueline.

Day5.:Thefirstsignsof thebeginningofossification are clearly indicated by a darkershadowinthecentralpartoftheapicalthirdofthesocketpresentinthexray.Thisfindingcor-relateswith thehistologicalfindings from thesameperiod, i.e.with theappearanceofbonetrabeculesalongthealveolarwalls.

Day7.The cortex is barely distinguished,whilethefundusofthesocketisseenasamuchclearerX-rayshadow3.

Day 8. Lamina dura is slightly less pro-nounced, while the lower parts of the socketshowamorepronouncedX-rayshadow,which

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7. dan:Korteks se slabo razlikuje, dok sefundusalveolevidikaojasnijaradiološkasen-ka3.

8.dan:Laminadurajemalomanjeizražena,dokdonjidelovialveoleimajuizraženijuradio-loškasenku,štosepodudarasahistološkimna-lazomnakomesevididajeapikalnideoalveo-leispunjenmladomkostiiosteoidom.

10.dan:Laminaduraidaljejevidljivaaliskoroizjednačenasaokolnomkosti,doksera-diološkasenkanepojačavauostalimdelovimarane4. U ovoj fazi histološki nalaz pokazujeda je alveola do polovine popunjenamladomkošću.

14.dan:Alveolajepopunjenatkivomkojedajegustuijednakuradiološkasenku3Alveolajeispunjenasadržajemčijajeradiološkasenkapribližnaokolnojkosti,dokselaminadurajed-vanazire.Nahistološkomnalazuvidisejasnosolidnoformiranaretikularnakostkojaispunja-vaalveolu.

20. dan: Prvobitno radiološka rasvetljenjeskorojeupotpunostizamenjenosenkomkojaje po intenzitetu slična okolnoj kosti. Laminadura se više ne razaznaje . I u ovom perioduradiološki nalaz sepoklapa sahistiloškimna-lazom-nemakorteksanapovršinikosti,mladakostpotpunoispunjavaalveolu.

30.dan:Bezubamestasasvimsuzamenjenatkivomčijajeradiološkasenkajednakasaoko-linom,takodaskoronijemogućeodreditigdesuzidovinekadašnjealveole3

60.dan:Praznaalveolaimaisteradiološkekarakteristikekaookolnaintaktnakost3.Histo-loški, jošu ranijemperiodu,50.danaodeks-trakcijealveoluispunjavazrelalamelarnakost.

Procenom mineralne gustine kosti i total-nogkoštanogvolumenanakonekstrakcijezubautvrđeno je da jemaksimalni porastminerla-negustineod1-14.dana,pričemusenastav-ljado56.dana,dokkoštanivolumenrastedo56.danaazatimsesmanjujedo112danaposleekstrakcije12.

Ostale studije od uticaja na praćenje procesa zarastanja ekstrakcione rane na eksperimentalnom modelu pacova

Koštani morfogenetski protein

Koštani matrks je bogat faktorima rastameđukojimajeikoštanimorfogenetskiprotein

is inagreementwith thehistologicalfindings,whichshowsthattheapicalpartofthesocketfilledwithyoungboneandosteoid.

Day10.Laminaduraisstillvisiblebutal-most indistinguishable from the surroundingbone,whiletheX-rayshadowisnotamplifiedintheotherpartsofthewound4.Atthisstage,histologicfindingsshowsthatthesocketishalffilledwithyoungbone.

Day14.Thesocketisfilledwithtissuethatprovidesadenseandevenxrayshadow3,whilethelaminaduraisbarelyvisible.Ahistologicalfindings clearly shows solid formed reticularbonefillingthesocket.

Day 20. The previous X-ray-illuminationhasalmostcomplitelybeenreplacedbyashad-owsimilar in intensity to theoneof the sor-roundingbone.Laminadura isno longerdis-cernible. In this period, radiographic findingsagrees with the histological findings in thatthereisnocortexonthesurfaceoftheboneandthat the young bone has complitely filled thesocket.

Day30.Edentulousspotshavebeencom-pletely replaced by tissuewithX-ray shadoweventothelocalarea,sothatitisalmostpos-sibletodistinguishthewallsoftheformeral-veola3.

Day60.Atthispointtheemptysockethasthesameradiologicalcharacteristicsasthesur-roundingintactbone3.Histologicalythesockethasbeenfilledwithmaturelamellarboneatanearlyerperiodonthe50thdayaftertheextrac-tion.

The assessment of mineral density of theboneandtotalbonevolumeaftertoothextrac-tion,confirmesthattheincreaseinthemineraldensity ismaximal in the period between the1thandthe14thday,andthatitcontinuestoriseuntil56thday,aswellasthebonevolumewhichafterwardsdecreasesuntil the112th dayaftertheextraction12.

Other studies relevant to the wound healing process in an experimental model of rat

Bone morphogenetic protein

Bonematrix is rich ingrowth factors, in-cludingthebonemorphogeneticprotein(BMP),whichissynthesizedandsecretedfromtheos-teoblastsandincorporatedintothematrixdur-ingboneformation.BMP,whichisreleaseddur-ingbone resorption can inducedifferentiationofmesenchymalcellsintoosteoblasts(osteoin-

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(BMP)kojisesintetišeisekretujeizosteoblastaiinkorporiraumatriksutokuformiranjakosti.BMPkoji se oslobađa u toku resorpcije kostimožeindukovatidiferencijacijumezenhimalnihćelijauosteoblaste(osteoindukcija)stimulišućiregeneracijuireparacijukosti. Eksperimentalnestudije ukazale su da je BMP efikasan ulečenju koštanih defekata u kostima različitihprirode13,14.Posebno,važnisuBMP7iBMP2 (rhBMP-2 i rhBMP-7) koji su korišćeni saočiglednimuspehomzalečenjekoštanihlezijauortopedskojimaksilofacijalnojhirurgiji15.

BMP je rastvorljiv i difunduje brzo ubiološkim medijumima. Da bi se postiglaoptimalna efikasnost, BMP bi trebalo da imasa nosač-materijal koji produžava vremeboravka namestu aplikacije, a kojimora bitibiokompatibilan.Utesvrhekoristesehidroksi-apatit, mineralizovani i demineralizovanikoštanimtriks,kompozitiibiostaklo.

Koštani morfogenetski protein u kom-binaciji sa hidroksiapatitom aplikovan posleeksrakcije zuba u koštanu alveolu pacovastimuliše osteogenezu, ali ne ubrzava procesosteointegracije16.Udrugojstudijigdejepra-ćeno dejstvo samog hidroksiapatita i u kom-binaciji sa koštanim morfogenetskim pro-teinom, rana je kod pacova koji su tretiranisamo hidroksiapatitom brže zarastala do 21.postoperativnogdana,dokjenaistomstadijumuzarastanja bila 42. postoperativnog dana kodobeispitivanegrupe17.

Zračenje Studijakojaispitujeuticajlokalnogzračenja

i zračenja celog tela na pojavu osteoblasta ualveolarnoj kosti pacova nakon ekstrakcijemaksilarnog molara pokazala je malo razlikeizmeđu jedinki koje su bile lokalno zračenedozomzračenjaod6Gyine-zračenihjedinki.Nasuprot tome, u grupi kod koje je zračenocelo telo došlo je do odloženog zarastanjarane.Ultrastrukturna studija jepokazalada jeosteoblastanakonzračenjacelogtelabilomanjekaoidasuimalislabijerazvijeneorganele18.

Laser male snageLasermalesnage imabiostimulativniefekat,

ali efekat na zarastanje ekstrakcione ranekodeksperimentalnihpacovajediskutabilan.Neki

duction)bystimulatingboneregenerationandreparation. Experimental studies have shownthatBMPiseffectiveintreatingbonedefectsindifferenttypesofbones13,14.Inparticular,BMP7 and BMP 2 (rhBMP-2 and rhBMP-7) usedwithsignificantsuccesintreatmentofbonele-sions in orthopedicandmaxillofacialsurgeryareimportant15.

BMPissolubleanddiffusesrapidlyinbiolog-icalmedia.Inordertoachieveoptimalefficien-cy,BMPshouldhavethecarrier-materialwhichincrease the stay at the application spot, andwhichmustbebiocompatible.Forthispurposeshydroxy-apatite,mineralizedanddemineralizedbonematrix,compositesandbioglass isused. BMP combined with hydroxyapatite appliedafter the toothextraction in thebone socketoftheratstimulatesosteogenesisbutdoesnotacceleratetheprocessofosteointegration16.Inanotherstudyfocusingontheeffectofthehy-droxy-apatitealoneandwherecombinedwithBMPshowsthatthewoundinratstreatedonlywithhydroxyapatitehealesfasteruntilthe21st postoperativeday,whileonthe42ndpostopera-tivedaythehealingwasatthesamestagewithbothoftheexaminedgroup17.

X-ray radiationAstudyontheinfluenceoflocalirradiation

andwholebodyradiationontheappearanceofosteoblastsinratalveolarboneaftermaxillarymolarextractionshowedtherewaslittlediffer-encebetweenindividualsthatwerelocallyirra-diatedradiationdoseof6Gyandnon-radiatedanimals.Ontheotherhand,thegroupexposedtothewholebodyradiotherapydisplayedde-layed healing of the wound. Ultrastructuralstudy showed that therewere less osteoblastsafter whole body radiation and that they hadlessdevelopedorganelles18.

Low power laser (LPL)LPLhasastimulativeeffect,buttheeffect

onhealingofextractionwoundsinexperimen-talratsisquestionable.SomeauthorsstatethatLPL increases the activity of bone cells (re-sorptionandformation)aroundthebonedefectwithoutchangingthestructureofthebone19,20 whereasinanotherstudylowpowerlaserdoesnotaccelerateepithelializationandosteogene-sisaftertoothextractioninrats21.Astudydoneat our institution22 documents evident bios-

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autorinavodedalasermalesnagepovećavaak-tivnostkoštanihćelija (resorpciju i formaciju)oko koštanog defekta bez promene strukturekosti19,20dokudrugojstudijilasermalesnagenije ubrzao epitelizaciju i osteogenezu nakonekstrakcije zuba kod pacova21.U radu autoraiznašeinstitucije22,lasermalesnagepokazujeevidentanbiostimulativnipotencijalnaekstrak-cionim ranama na drugom eksperimentalnommodelu.Analizomekstrakcioneranepasakojajezračena7danaposleekstrakcije,uočena jeznačajnarazlikauizgleduekstrakcionerane7,14,21,28i35danaposleekstrakcije.

Uprvojnedeljikodnetretitanihranaslu-zokožajeprekrivenahiperplastičnimepitelom,prisutanjesnažansubepitelnizapaljenskiinfil-trat,malogranulacija,intraosealnainflamacijaiodsustvofibroplazije.Odosteoblastičnaaktiv-nostizostaje.Kodranatretiranihlaserommalesnagesluzokožapokazujevećistepenhiperpla-zije,intraosealnideoranepokazujeizrazitegra-nulacijeifibroplazijekaoinovostvorenekošta-negredice.Perifernideoranepokazujesnažnuosteoblastičnuaktivnost.

U drugoj nedelji, kod rana ne tretiranuhlaserom sluzokoža pokazuje blagu subepitel-nu inflamaciju, postoji izražena fibroplazija igranulacije.Perifernideoranepokazujenovo-stvorenekoštanegredice,dokihucentralnomdeluranenema.Udrugojgrupisluzokožajeudrugoj nedelji normalnog izgleda. Postoji os-teoblastičnaaktivnostusvimsegmentima.

Trećenedeljeposleekstrakcijesluzokožajenormalnog izgleda kod nezračenih slučajeva.Periferni delovi rane sadrže zrelu lamelarnukost,acentralninezrelu,vlaknastukost.Posletretmana laserommale snage u trećoj nedeljisluzokožajetakođenormalnegrađe,osteobla-stična aktivnost je vrlo izražena, tako da imavišezrelenegonezrelekosti.

Poslečetirinedeljeintraosealnideloviranesuizgrađeniodgracilnihkoštanihgredica.Kodtretiranihranapostojeizraženijekoštanegredi-ce.

Poslepetnedeljakodnetretiranihranapo-stoje zrele koštane gredice i koštana srž. Ucentralnim delovima rane postoji fokus ožilj-nogvezivnogtkiva.Kodranatretiranihlaserompostojezrelekoštanegrediceikoštanasrž,bezfokusaožiljačnogvezivnogtkiva.

Bioptron lampaEkstrakciona rana koja prirodno zarasta,

kodeksperimentalnihpacovapočinjedaepitel-

timulativingpotencial of lowpower laseronextraction woundof thesecondexperimentalmodel. The analysis of extraction wounds ofdogs,whichisradiated7daysafterextraction,showsasignificantdifferenceintheappearanceofextractionwounds7,14,21,28and35daysafterextraction.

Mucosaoftheuntretedwoundsinthefirstweek iscoveredwithhyperplasticepithelium,there is a strong subepithelial inflammatoryinfiltrate, a bit of granulationes, intraosseousinflammation and the absenceoffibroplasion.Osteoblastic activity is missing. In woundstreated with low-power laser the mucosesshows a higher degree of hyperplasia, in-traosal part of the wound shows pronouncedgranulationesandfibroplasiaaswellasnewlydeveloped bone trabeculas. Peripheral part ofthewoundshowsstrongosteoblasticactivity. Inthesecondweek,themucosaoftheuntreat-ed woundshowsmild subepithelial inflama-tionandthereisalsoapronounced,fibroplasiaandgranulation.Peripheralpartof thewoundshows newly formed bone trabeculas, whilethereisnoneinthecentralpartofthewound.Inthesecondgroupthemucosalooksnormalinthesecondweek.Thereisosteoblasticactivityinallsegments.

Inthethirdweekaftertheextractionthemu-cosaappearstobenormalinthegrouphasn’tbeen exposed to radiation.Peripheral parts ofthewound containmature lamellar bone, andcentralimmature,fibrousbone.ThemucosaofthewoundtreatedwithLPLalsoappearstobenormal in the third week after the treatment,osteoblastic activity ishighlypronounced,sothereismoreofthematurethantheimmaturebone.

After four weeks in untreated gruop in-traosalpartsofthewoundareconstructedfromgraceful bone trabeculas. The treated wounddisplaced bone trabecula that are more pro-nounced.

After five weeks there are mature bonetrabecula and bone marrow in the untreatedwounds.ThereisalsoafocusofconnectivescartissueInthecentralpartsofthewounds.InthewoundsthattreatedwithLPLtherearematurebonetrabeculasandbonemarrowwithouththeconnectivescartissuefocus.

Polarized light (Bioptron lamp)Naturally healing wound in experimental

ratsbeginsepitelizationontheseconddayafter

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iziradrugogdanaposleekstrakcije,azavršetakepitelizacijejeosmogdana4.Poddejstvompo-larizovanesvetlostiekstrakcinaranaepiteliziradevetogdana.Mikromorfološkinalazdevetogdanaposleekstrakcijepokazujedajeepitelbezepitelaregenerisansabazalno-ćelijskomhiper-plazijomisapovećenimmitotskimindeksomihiperhromatizacijom jedara u njegovoj donjojtrećini22.

ZaključakZarastanjenormalneekstarkcioneranekod

pacova počinje sa pojavom gingivalnog epi-teladrugogpostoperativnogdana, a završetakepitelizacje je osmog dana.Kost počinje pro-gresivnodasestvaračetvrtogpostoperativnogdana,apetogpostojividljivaradiološkasenka.Intenzivnostvaranjekosti trajedodvadesetogpostoperativnog dana sa jasnom radiološkom senkomutomperiodu.Lamelarnakostprisutnaje šezdeset danaposle ekstrakcije, kada senasnimkupraznaalveolanerazlikujeodokolnekosti.Fazaremodelovanjaalveolarnihrubovasenastavljado112.danaposleekstrakcije.Nabržezarastanjeekstrakcioneranekodeksperi-mentalnih pacova nisu uticali koštani morfo-genetskiprotein(BMP),lasermalesnageipo-larizovanasvetlost.

theextractionandcompletestheepitelizationattheeightday4.Under the influenceof thepo-larized light the extractionwound finishwithepitelization on the ninth day. Micromorpho-logicalrecordontheninthdayafterextractionshowsthat theepitheliumwithoutepitheliumwithbasal-cellhyperplasiawasregeneratedandwiththeincreasedmitoticindexandhiperhro-matizationofthenucleusesinitslowerthird22.

ConclusionThehealingof normal extractionwounds

inratsbeginswiththeappearanceofthegumsepithelium of the second postoperative day,andtheendoftheepitelizationisontheeighthday.Theprogresiveformationofbonebeginson the fourth day after the exodontia, and onthefifththereisavisiblex-rayshadow.Theintensebone formation lastsuntil the twenti-ethpostoperativedaybyaclearX-rayshadowwhithin that period. Lamellar bone is presentis 60th days after extraction, when the emptysocket can not be distinguished from the sur-roundingboneontheX-ray.Thephaseoftheallveolarridgeremodelingcontinuesuntil112th daysafterthetoothextraction.BMP,LPL,andpolarizedlighthadnoeffectonthethehealingoftheextractionwoundinexperimentalrats.

Tabela 1. Biologija zarastanja ekstrakcione rane kod eksperimentalnih životinja zračenih laserom male snage

Ekstrakcione rane ne tretirane laserom male snage

Ekstrakcione rane tretirane laserom male snage

1. nedelja Sluzokoža-hiperplastičniepitel,subepitelniza-paljenskiinfiltratKost-inflamacija,odsustvofibroplazije

Sluzokoža-većistepenhiperplazije,Kost-granulacije,fibroplazija,koštanegredice,prisutnaosteoblastičnaaktivnost

5. nedelja Kost-zrelekoštanegrediceikostnasrž,ucentralnimdelovimaranefokusožiljnogvezivnogtkiva

Kost-zrelekoštanegredice,kostnasrž,nemafokusaožiljnogtkiva

Table 1. Biological events of extraction wounds in experimentl animal treated with LPL

ExtractionwoundsnottreatedwithLPL ExractionwoundstreatedwithLPL

1.week Mucosa-hyperplasticepithelium,astrongsubepithe-lialinflammatoryinfiltrate.Bone-inflamation,osteoblasticactivityismissing

Mucosa-higherdegreeofhyperplasia,Bone-pronouncedgranulationesandfibroplasia,newlydevelopedbonetra-beculas.osteoblasticactivity

5. week Bone-maturebonetrabeculaandbonemarrowAfocusofconnectivescartissue

Bone-maturebonetrabeculasandbonemarrowwithouththeconnectivescartissuefocus

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Address of correspondence:SimonaStojanović,DDS,

Ph.D.StudentHusinjskihrudara5,Niš

telefon/fax:+38118552730mobilni/+381692245322

E-mail:tarana.simona@gmail.com

Adresa za korespondenciju:DrSimonaStojanovićSaradnikunastaviHusinjskihrudara5,Ništelefon/fax:+38118552730mobilni/+381692245322E-mail:tarana.simona@gmail.com

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