engleski

Histomorphometric analysis of osteoid/bone deposition after three different root canal therapy procedures

Aim: The aim of this research was to analyse osteoid/bone deposition during initial phases of periapical lesion healing after three different protocols of root canal therapy. Methods: Periapical lesions were induced in 9 mongrel dogs by exposing the pulps to the oral environment for 35 days. Seventeen root canals were instrumented and filled to the apical delta, which was confirmed radiographically (group 1). Animals in group 2 (21 roots), after the same procedure, received 10 mg/kg doxycycline (Hiramicin, Pliva d.d., Zagreb, Croatia) per os daily for 12 days. In group 3 (20 roots) we performed instrumentation reaching periapical area to the point determined by apex locator (EED 11, Struja, Zagreb, Croatia). Roots were filled to the lenght of physiological foramen which was confirmed radiographically. At the same day, one animal in groups 1 and 3 received intraperitoneal injection of vital dye Procion Red. Animals were sacrified 70 days after pulp exposure. Undemineralized unstained sections 5 - 7 &#61549; m thick were analysed for traces of doxycycline and vital dye with fluorescent microscope. Osteoid surface, osteoid thickness and osteoclast index were measured by light microscope on Toluidine Blue stained sections. Statistical analyses were performed by ANOVA test. Results: Qualitative analysis of new bone formation with vital dye and doxycycline fluorescence showed lines close to the bone surface in group 1, but further away from bone surface in groups 2 and 3. Osteoid thickness was statistically significantly different between groups 1 (15, 62 &#956; m &plusmn ; ; ; 7, 41) and 2 (14, 32 &#956; m &plusmn ; ; ; 5, 06) ( p<0, 05), and groups 2 and 3 (16, 26 &#956; m &plusmn ; ; ; 6, 46) (p<0, 001). Osteoid surface was statistically significantlly different between groups 1 (10, 34 % &plusmn ; ; ; 11, 60) and 3 (33, 21 % &plusmn ; ; ; 21, 43) (p<0, 001), and groups 1 and 2 (30, 36 % &plusmn ; ; ; 15, 51) (p<0, 001). Osteoclast index was statistically significantlly different between groups 1 (111, 34 mm-1 &plusmn ; ; ; 115, 46) and 2 (43, 13 mm-1 &plusmn ; ; ; 41, 25) (p<0, 001), and groups 1 and 3 (27, 01 mm-1 &plusmn ; ; ; 39, 03) (p<0, 001). Conclusion: Administration of doxycycline in group 2 and more invasive therapeutic approach in group 3, enhanced healing potential demonstrated with lower osteoclast index and greater osteoid surface in comparison to group 1. It is debatable how doxycycline affects osteoid deposition because lowest osteoid thickness was measured in group 2.

periapical periodontitis; dog; osteoid; bone; root canal therapy

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