engleski

Quantitative Fluorescence Analisys of Bone Deposition After Doxycycline Administration During Endodontic Therapy - A Pilot Study

Aim: Besides it's antimicrobial properties, doxycycicline is known as inhibitor of bone resorption, as well as promotor of bone formation, due to it's effect on osteoclasts and osteoprogenitor cells. Doxycycline is also used as a fluorescent marker for bone deposition. As a sequel to previous studies, the aim of this research was to analyse bone deposition quantitatively during initial phases of periapical lesion healing, after of root canal therapy combined with doxycycline administration. Methods: Periapical lesions were induced in 2 mongrel dogs by exposing the dental pulps to the oral environment. After 35 days of pulp exposure, five root canals of each animal were instrumented and filled to the apical delta, which was confirmed radiographically. At the same day, one animal (group 1, 5 roots) received intraperitoneal injection of vital dye Procion Red. Second animal (group 2, 5 roots), after endodontic procedure, received 10 mg/kg doxycycline (Hiramicin, Pliva d.d., Zagreb, Croatia) per os daily, for 12 days. Animals were sacrificed 70 days after pulp exposure, and mandibles embedded in methyl-metacrilate. Undemineralized unstained sections 5 - 7 mm thick (Fig. 1) were analysed for traces of Procion Red (group 1) and doxycycline (group 2) with fluorescent microscope. Histomorphometric index of mineralising suface, as a fraction of periapical lesion bone surface, was mesured using computer program (Issa, VAMS, Zagreb, Croatia) (Figure 2). Statistical analyses were performed by Mann-Whitney test. Results: The analysis of sections, containing Procion red vital dye in group 1 (Figure 3), and doxycycline in group 2 (Fig. 4), showed fluorescent lines marking new bone formation in both groups. There was statistically significant difference in mineralising surface index between groups 1 (median = 28, 40 %, 5 – 95 % = 17, 99 – 47, 46 %) and 2 (median = 66, 97 %, 5 – 95 % = 62, 50 – 75, 46 %), (p = 0, 010516) (Graph 1). Conclusion: Administration of doxycycline in group 2 enhanced healing potential demonstrated by greater mineralising surface index, in comparison to group 1. This result correlates with the results of quantitative analysis of osteoid surface, osteoid thickness and osteoclast index, after doxycycline administration during endodontc therapy, shown in previous studies.

Apical periodontitis; root canal therapy; doxycycline; bone healing; dog

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