Avaliação dos tecidos ao redor de implantes osseointegrados com e sem peri-implantite induzida e a relação com a ocorrência de osteonecrose dos maxilares associada à terapia medicamentosa / Tissue evaluation around osseointegrated implants with and without induced peri-implantitis and the relation with the occurrence of medication-related osteonecrosis of the jaw

Objetivo: O objetivo deste trabalho foi avaliar a resposta dos tecidos periimplantares em condições de normalidade e com peri-implantite induzida por ligadura, em implantes osseointegrados na maxila de ratas senescentes submetidas ao tratamento posterior com dosagem oncológica de zoledronato. Material e métodos: Foram utilizadas 28 ratas Wistar (Rattus novergicus) iniciando o experimento com aproximandamente 14 meses de idade e pesando entre 350 e 450g. Os animais foram submetidos à exodontia do incisivo superior direito e instalação imediata de um implante de titânio com 2,5 mm de diâmetro por 5,7 mm de comprimento, onde após quase 2 meses, foi realizada a cirurgia de reabertura dos implantes e instalação de um cicatrizador. Após uma semana, os animais foram divididos de acordo com os seguintes tratamentos: veículo, administração de solução salina estéril 0,9% intraperitoneal (Grupo VEI); zoledronato, com administração de 100 µg/Kg de zoledronato (Grupo ZOL); veículo com peri-implantite experimental (Grupo VEI-PIE) e; zoledronato com peri-implantite experimental (Grupo ZOL-PIE), com a indução da peri-implantite experimental (PIE) por meio de uma ligadura de algodão 5 semanas após o início do tratamento medicamentoso. A porcentagem de tecido ósseo total (PTO-T) e porcentagem de tecido ósseo não vital (PTO-NV) foram analisadas histometricamente, e foram realizadas imunomarcações para fosfatase ácida resistente ao tartarato (TRAP), fator de necrose tumoral alfa (TNFα), interleucina 1 beta (IL1-ß), fator de crescimento endotelial vascular (VEGF) e osteocalcina (OCN). Os dados foram submetidos à análise estatística. Resultados: O grupo ZOL mostrou persistência de inflamação no tecido conjuntivo peri-implantar e uma quantidade considerável de PTO-NV ao redor do implante quando comparado com VEI. A inflamação peri-implantar foi mais exacerbada em ZOL-PIE, assim como, o comprometimento da vitalidade do tecido ósseo ao redor dos implantes quando comparado com VEI-PIE. Conclusão: Conclui-se que o tratamento com altas doses de zoledronato ocasiona alterações ao nível periimplantar, dentre elas, um aumento da inflamação local, e da PTO-NV ao redor do implante osseointegrado, o que pode representar um possível fator de risco para o surgimento da osteonecrose dos maxilares associada à terapia medicamentosa relacionada ao implante odontológico (ONMM-IO). Na presença da PIE há uma exacerbação da inflamação e um aumento ainda maior da PTO-NV, o que implica em um importante fator de risco agravante para o surgimento da ONMM-IO no modelo experimental estudado(AU)

Aim: The aim of this study was to evaluate the response of peri-implant tissues under normal conditions and with ligature-induced peri-implantitis, in osseointegrated implants in the maxilla of senescent rats submitted to subsequent treatment with oncological dosage of zoledronate. Material and methods: Twenty-eight female Wistar rats (Rattus novergicus) were used, starting the experiment at approximately 14 months of age and weighing between 350 and 450g. The animals underwent extraction of the upper right incisor and immediate installation of a titanium implant 2.5 mm wide by 5.7 mm long, where after almost 2 months, surgery to reopen the implants and installation of a healer was performed. After one week, the animals were divided according to the following treatments: vehicle, administration of 0.9% sterile saline intraperitoneally (VEI Group); zoledronate, with administration of 100 µg/Kg of zoledronate (ZOL Group); vehicle with experimental peri-implantitis (VEIPIE Group) and; zoledronate with experimental peri-implantitis (ZOL-PIE Group), with the induction of experimental peri-implantitis (PIE) by means of a cotton suture 5 weeks after the start of drug treatment. The percentage of total bone tissue (PBT-T) and percentage of non-vital bone tissue (PBT-NV) were analyzed histometrically, and immunostaining for tartrate-resistant acid phosphatase (TRAP), tumor necrosis factor alpha (TNFα), interleukin 1 beta (IL1-ß), vascular endothelial growth factor (VEGF) and osteocalcin (OCN). Data were subjected to statistical analysis. Results: The ZOL group showed persistence of inflammation in the peri-implant connective tissue and a considerable amount of PBT-NV around the implant when compared to VEI. Peri-implant inflammation was more exacerbated in ZOL-PIE, as well as compromised bone tissue vitality around the implants when compared to VEI-PIE. Conclusion: It is concluded that treatment with high doses of zoledronate causes changes at the peri-implant level, among them, an increase in local inflammation, and in PBT-NV around the osseointegrated implant, which may represent a possible risk factor for the emergence of medication-related osteonecrosis of the jaws implant- associated (MRONJ-IA). In the presence of PIE, there is an exacerbation of inflammation and an even greater increase in PBT-NV, which implies an important aggravating risk factor for the emergence of MRONJ-IA in the experimental model studied(AU)

Local application of statins in the treatment of experimental periodontal disease in rats

Abstract Objective The objective of this study was to evaluate the local effects of statins as adjuvants for treatment by scaling and root planing (SRP) of periodontal disease induced in rats. Material and Methods Ninety rats were used in the present experiment. Periodontal disease was induced in all animals using a cotton thread placed in the left first mandibular molar. After 7 days of induction, the bandage was removed and the animals were divided into three groups: 1) NT group (n=30), no treatment; 2) SRP group (n=30): SRP and irrigation with control gel; 3) S group (n=30) - SRP and irrigation with Simvastatin. Ten animals from each group were euthanized at 7, 15 and 30 days after treatment. Gingival biopsy specimens were processed to analyze the expression of matrix metalloproteinase 8 (MMP-8). The mandibles were removed and submitted to radiographic and laboratory processing for histometric analysis. Results The S group showed a significantly lower expression of MMP-8 compared to NT and SRP groups in all experimental periods. In the radiographic and histometric analyses between the groups, S group showed a significantly lower bone loss (BL) compared to NT and SRP groups in all experimental periods. Conclusions Within the limits of this study, it can be concluded that locally applied statin was effective as an adjuvant treatment for SRP in rats with induced periodontal disease.

Efeitos da Sinvastatina como coadjuvante no tratamento da doença periodontal induzida em ratos / Effects of Simvastatin as supporting in the treatment of periodontal disease induced in rats

O estudo avaliou a Sinvastatina no tratamento da doença periodontal (DP) em ratos. Trinta e seis animais foram divididos em Grupo Controle (C) que receberam oralmente soro fisiológico e Sinvastatina (S) que receberam oralmente Sinvastatina. Após 24 horas, a DP foi induzida utilizando-se um fio de algodão na região dento-gengival dos primeiros molares inferiores esquerdos. Após 7 dias, a ligadura foi removida e os animais receberam raspagem e alisamento radicular (RAR) e irrigação com soro fisiológico. Os animais foram eutanasiados aos 7, 15 e 30 dias. Radiograficamente, o tratamento com RAR mostrou uma menor perda óssea (PO) no Grupo S comparado ao C em todos os períodos. Concluiu-se que a Sinvastatina associada à RAR foi efetiva na redução da PO em ratos.

The study evaluated simvastatin in the treatment of periodontal disease (PD) in rats. 36 animals were divided into control group (C) receiving oral saline and Simvastatin (S) who received oral simvastatin. After 24 hours the PD was induced using a cotton yarn in the dento-gingival area of the first left molar. After 7 days the ligature was removed and animals received scaling and root planing (SRP) and irrigation with saline. The animals were sacrificed at 7, 15 and 30 days. Radiographically treatment with SRP showed less bone loss (BL) in the S group compared to C in all periods. It was concluded that SRP associated with simvastatin was effective in reducing the BL in rats.a