RESUMO
Surgical trauma in those under a prolonged use of bisphosphonates, can lead to mediation-related osteonecrosis of the jaw (MRONJ). This study aimed to evaluate the preventive therapies for MRONJ. Following four cycles of zoledronic acid administration, Wistar rats had their molar extracted, and were organized into nine treatment groups: negative control group (NCG), treated with saline solution and blood-clot in the alveolus; positive control group (PCG), with blood-clot in the alveolus; BG, ß-tricalcium phosphate-based biomaterial; DG, 10% doxycycline gel; aG, antimicrobial photodynamic therapy; and DBG, aBG, aDG, and aDBG, using combination therapy. After 28 days, the lowest bone volume (BV/TV) was reported in PCG (42.17% ± 2.65), and the highest in aDBG (69.85% ± 6.25) (p < 0.05). The higher values of daily mineral apposition rate were recorded in aDBG (2.64 ± 0.48) and DBG (2.30 ± 0.37) (p < 0.001). Moreover, aDBG presented with the highest neoformed bone area (82.44% ± 2.69) (p < 0.05). Non-vital bone was reported only in the PCG (37.94 ± 18.70%). Owing to the key role of the biomaterial, the combination approach (aDBG) was the most effective in preventing MRONJ following tooth extraction.
Assuntos
Osteonecrose da Arcada Osseodentária Associada a Difosfonatos , Conservadores da Densidade Óssea , Fotoquimioterapia , Animais , Antibacterianos , Materiais Biocompatíveis , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/tratamento farmacológico , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/etiologia , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/prevenção & controle , Fosfatos de Cálcio , Difosfonatos , Doxiciclina , Fotoquimioterapia/efeitos adversos , Ratos , Ratos Wistar , Solução Salina , Extração Dentária/efeitos adversos , Ácido ZoledrônicoRESUMO
BACKGROUND: Very limited information is available from in vivo studies about whether smoking and/or nicotine affect gingival tissues in the absence of plaque. The purpose of this study is to evaluate the effect of the systemic administration of nicotine in the proliferation and counting of fibroblast-like cells in the gingival tissue of rats. METHODS: Thirty adult male Wistar rats were randomly assigned into two groups to receive subcutaneous injections of a saline solution (control group = group C) or nicotine solution (group N; 3 mg/kg) twice a day. The animals were euthanized 37, 44, or 51 days after the first subcutaneous injection. Specimens were routinely processed for serial histologic sections. Five fields of view in the connective tissue adjacent to the gingival epithelium and above the alveolar bone crest of the maxillary first molar were selected for the counting of fibroblast-like cells. Data were statistically analyzed (P <0.05). RESULTS: The intergroup analysis detected a lower number of fibroblast-like cells in group N compared to group C on days 37 (2.65 ± 1.41 and 6.67 ± 3.25, respectively), 44 (2.70 ± 1.84 and 8.57 ± 2.37, respectively), and 51 (2.09 ± 1.41 and 7.49 ± 2.60, respectively) (P <0.05). The quantification of fibroblast-like cells showed no significant difference (P >0.05) in the intragroup analysis of control and nicotine throughout experimental periods. In the intergroup analysis, group N had reduced proliferating cell nuclear antigen-positive fibroblasts compared to group C in all periods (P <0.05). CONCLUSION: The daily systemic administration of nicotine negatively affected, in vivo, the number and proliferation of fibroblast-like cells in the gingival tissue of rats.