engleski

EVALUATION OF BONE REMODELING AFTER ENDODONTIC THERAPY OF PERIAPICAL LESION

Aim The aim of the study was to evaluate bone remodeling by measuring osteoid surface, osteoid thickness, osteoclast index and inflammatory cell count after two different approaches in endodontic therapy of periapical lesion on dogs’ teeth. Methods After inducing periapical lesion in 23 mandibular premolars (37 root canals) from six mongrel dogs, 17 root canals were instrumented to the apical delta with crown-down technique using ProFile Ni-Ti rotary instruments and filled to the same lenght with Thermafill obturation technique and Top Seal cement (group 1). The other 20 root canals (group 2) were instrumented using controlled overinstrumentation technique to the point determined electronically (electronic apex locator EED-11, Struja, Zagreb, Croatia). Teeth were obturated with Thermafill at the length 2 mm shorter than the working length. Lenght of obturation was confirmed radiographically and access cavities sealed with amalgam in both groups. The animals were sacrified 35 days after the end of endodontic treatment. Undemineralized sections 5 – 7 μ m thick were stained with toluidine blue. The histomorphometric indices (osteoid surface, osteoid tickness, osteoclast index and inflammatory cell count) were measured by light microscopy using computer program (ISSA, Vams, Zagreb, Croatia). Results The difference between groups was statistically significant in all the measured indices. In group 1 osteoid surface was lower (10, 34 %  11, 60), as well as osteoid thickness (15, 62 μ m  7, 41) and inflammatory cell count (111, 39 &plusmn ; ; 75, 81), while osteoclast index was higher (111, 34 mm-2 &plusmn ; ; 115, 46). In group 2 osteoid surface was higher (33, 21 %  21, 43), as well as osteoid thickness (16, 26 μ m  6, 46) and inflammatory cell count (137, 62 &plusmn ; ; 46, 34), while osteoclast index was lower (27, 00 mm-2 &plusmn ; ; 39, 03). Statistical analysis was performed using Mann – Whitney U test. Conclusion Results obtained by measuring histomorphometric indices indicate sustained bone resorption activity in group1 and faster bone formation in group 2. Greater number of inflammatory cells in group 2 is probably caused by additional trauma of periapical tissues during overinstrumentation. This trauma does not interfere with bone remodelling.

endodontic therapy; bone remodeling; dog

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