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Abstract Objective The aim of this study was to evaluate the local effect of nanosilver irrigation on experimentally-induced periodontitis in rats. Material and Methods: fifty five male albino rats were included in this study. On the first day, 5 rats were sacrificed as healthy group for identification of normal radiological and histological charasteristics of interdental alveolar bone between the maxillary incisors. Fifty rats were anesthetized; elastic rings were placed around the cervix of the right maxillary incisors for 7 days to induce periodontitis. On the eighth day, the ligatures were removed, five rats were sacrificed before any treatment (day zero treatment) and served as positive control group .The remaining 45 rats were randomly assigned to three groups as following: group I; rats not received any treatment. group II; rats treated with tetracycline hydrochloride (50 mg /mL). group III; rats treated locally with nanosilver (12.5μg /mL). Five animals from each group (I, II and III) were sacrificed at day 7, 15 and 30 after ligature removal. The areas of maxillary incisors were radiographic before processing for hematoxylin- eosin stain. Results: as local application of nanosilver in the experimentally - induced periodontitis in rats exhibited statistically significant increase in BMD from day 15 with statistically significant decrease in inflammatory cell infiltration from day 7 compared to as local application of tetracycline Conclusion: Subgingival irrigation with nanosilver solution in a concentration of 12.5 µg/ml can be used as an effective local therapy in treatment of periodontal disease (at least that induced in rats). However, this hypothesis must be further verified by clinical human trials before introducing in dental practice. Key words: nanosilver, tetracycline, rats, experimentally - induced periodontitis. Contents Title Page List of Tablets I List of Figures III Abbreviations IV Chapters I Introduction 1 II Review of Literature Periodontitis Important bacteria associated with periodontal disease Innate immunity and periodontal tissue destruction Adaptive immunity and periodontal tissue destruction Pathogenesis of periodontal disease Mechanisms of bone loss in periodontitis Macrophage colony-stimulating factor RANK and RANKL Osteoprotegerin RANKL ⁄osteoprotegerin ratio in inflamed periodontal tissues Intracellular regulators of osteoclasts Tumor necrosis factor receptor factor-6 Nuclear factor kappa-light-chain enhancer of activated B cells Activator protein-1 family Nuclear factor of activated T-cells Nanosilver NS synthesis Mechanisms of Ag-NPs antibacterial properties Free silver ion uptake Generation of reactive oxygen species Direct cell membrane damage Properties of nano-silver Antibacterial properties Antifungal properties Anti-inflammatory properties Antiviral properties Prevention of biofilm formation NS toxicity Tetracyclines Mechanisms of action Spectrum of activity Non-antibacterial TCs and pathologic bone loss Irrigation with tetracyclines Bacterial resistance<br Fig.10 A bar chart showing a comparison between the mean of interdental alveolar bone mineral densities of all groups. 63 Fig.11 A bar chart showing comparison of the bone mineral density within groups. 65 Fig.12 Histological appearance of the region between the maxillary incisor roots, healthy group 67 Fig.13 Histomicrography of interdental alveolar bone between maxillary incisors of rat in positive control group(at day zero) 68 Fig.14 Photomicrographs of interdental alveolar bone between maxillary incisors at day 7 after treatment in all groups. 69 Fig.15 Histopathological section in interdental alveolar bone in rat in positive control group (at day zero). 70 Fig.16 Histopathological section in interdental alveolar bone in rat of positive control group (at day zero). 71 Fig.17 Photomicrograph of interdental alveolar bone between maxillary incisors of a rat in group I (no treatment group) at day7. 73 Fig.18 Photomicrograph of interdental alveolar bone between maxillary incisors at day 15 after treatment in all groups. 74 Fig.19 Photomicrograph of interdental alveolar bone between maxillary incisors of a rat in group I (no treatment group) at day 30. 75 Fig.20 Photomicrograph of interdental alveolar bone between maxillary incisors at 30 days, after treatment in all groups. 76 Fig.21 Photomicrograph of interdental alveolar bone between maxillary incisors of a rat in group II (tetracycline treatment) at day 15. 77 Fig.22 Photomicrograph of interdental alveolar bone between maxillary incisors of a rat in group II (tetracycline treatment) at 30 days. 78 Fig.23 Histopathologicalogical section in interdental alveolar bone in rat in group III at day 15 (nanosilver treatment). 79 Fig.24 Photomicrograph of interdental alveolar bone between maxillary incisors from a rat at day 30 in group III. 80 Fig.25 A bar chart showing a comparison between the mean inflammatory cellular infiltrate counts of all groups. 84 Fig.26 A bar chart showing a comparison of the mean inflammatory cell count within groups. 86 |