Patterns of Osteoid Deposition in Periapical Lesion Healing Using Vital Dye

Svrha je istraživanja bila kvantitativno i kvalitativno opisati odlaganje osteoida prigodom cijeljenja periapeksnih lezija na psećim zubima nakon dvije različite endodontske terapije. Periapeksne lezije inducirane su na zubima šest pasa mješanaca trepanacijom i izlaganjem pulpe okoliki usne šupljine 35 dana. Životinje su nasumice podijeljene u dvije skupine. Sedamnaest korijenskih kanala instrumentirano je do apeksne delte crown-down tehnikom uporabom ProFile® NiTi rotirajućih instrumenata te napunjeno Thermafill® gutaperkama i Topseal cementom (skupina 1). U 2. skupini 20 je korijenskih kanala instrumentirano tehnikom kontrolirane preinstrumentacije do duljine određene elektroodontometrijski apeks-lokatorom EED11 (Struja, Zagreb, Hrvatska). Zubi su napunjeni Thermafillom ® do duljine 2mm kraće od radne duljine, a pristupni kaviteti svih zuba ispunjeni su amalgamom. U objema skupinama duljina kanalnoga punjenja potvrđena je radiološki. Istog je dana po jedna životinja iz svake skupine primila intrtaperitonealnu injekciju vitalne boje Procion Brilliant Red H8-BS (ICI Organics, Providence, R.I., USA). Životinje su žrtvovane 35 dana nakom endodontske terapije. Nedemineralizirani i neobojeni rezovi debljine 5-7 µm analizirani su s pomoću fluorescentnoga mikroskopa. Histomorfometrijski indeksi (površina osteoida i debljina osteoida) mjereni su s pomoću svjetlosnoga mikroskopa i računalnoga programa ISSA (Vams, Zagreb, Hrvatska) na rezovima obojenim Toluidinskim modrilom te je napravljena usporedba s kvalitativnom raščlambom preaparata vitalne boje. Pod UV svjetlom najčešće su se vidjele fluorescentne crte vitane boje koje označavaju granicu novostvorene kosti. Te su crte bile brojnije, jačeg intenziteta i udaljenije od površine resorbirane kosti u skupini 2. Samo u skupini 2 mogle su se vidjeti i fluorescentne trabekule i dvostruki prstenovi oko Haversovih kanala. Debljena osteioda bila je znatno veća u skupini 2 (skupina 1:15,62 µm ± 7,41; skupina 2: 16,26 µm ± 6,46; p < 0,001) kao i površina osteoida (skupina 1: 10,34 % ± 11,60; skupina 2: 33,21 % ± 21,43; p < 0,001). Za statističu raščlambu upotrijebljen je Mann-Whitney U test. Brojna područja fluorescencije te veća debljina i površina osteoida potvrđuju veće lučenje koštanoga matriksa u skupini 2.The aim of the study was to describe qualitively and quantitively osteoid deposition in periapecal lesion healing on dogs’ teeth after endodontic therapy based on two different approaches. Periapical lesions were experimentally induced in six mongrel dogs by exposing the pulps to the oral enviornment for 35 days. Animals were randomly divided into two groups. Seventeen root canals were instrumented to the apical delta with crown-down technique using ProFile® Ni-Ti rotary instruments and filled with Thermafill® guttapercha and Topseal® cement (group 1). In group 2, 20 root canals were instrumented using controlled overinstrumentation technique to the point determined using eletronic apex locator EED 11 (Struja, Zagreb, Croatia). Teeth were obturated with Thermafill® at the length 2 mm shorter than the working length, and access cavities sealed with amalgam The length of obturation was confirmed radiographically in both groups. On the same day, one animal in each group was injected intraperitoneally with vital dye Procion Brilliant Red H8-BS (ICI Organics, Providence, R.I., USA). Animals were sacrified 35 days after the end of endodontic tretment. Undemineralized and unstained sections 5-7 µm thick were first viewed under UV light for fluorescence. The histomorphometric indices (osteoid surface and thickness) were measured by light microscope using computer program ISSA (Vams, Zagreb, Croatia) on Toluidine Blue stained sections and compared with qualitative analysis of vital dye staining. Results Under UV light vital dye showed predominantly fluorescent lines marking the border of newly formed bone. Those lines were more numerous. Brighter and further away from resorbed bone surface in group 2. Fine fluorescent trabeculae and double rings around Haversian canals were seen in group 2 only. Osteoid thickness was significantly greater in group 2 (group 1: 15.62 µm ± 7.41; group 2: 16.26 µm ± 6.46; p < 0.001) as well as oteoid surface (group 1:10.34 % ± 11.60; group 2: 33.21 % ± 21.43; p < 0.001). Statistical analysis was performed using Mann-Whitney U test. Conclusion Numerous areas of fluorescence and greater osteoid thickness and osteiod surface show greater bone matrix preduction in group 2