Avaliação do potencial osteoindutor de implantes e miniplacas com revestimento à base de vidro bioativo via oxidação por plasma eletrolítico na otimização do reparo ósseo em ratos diabéticos
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Data
2023-02-17
Autores
Barbosa, Stéfany [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Diante dos efeitos promissores do biovidro no reparo ósseo, o presente trabalho teve como objetivo avaliar a capacidade osteoindutora do revestimento vidro bioativo sintetizado via oxidação por plasma eletrolítico na neoformação óssea de ratos diabéticos. Para isso, implantes de titânio comercialmente puro (Ticp) foram revestidos por PEO-BG (~ 45.0 Si, 24.5 Ca, 24.5 Na, 6.0 P; m/v %) via PEO (500 V, 1000 Hz, ciclo de trabalho de 10%, 420 s). Inicialmente, caracterizações de superfície foram conduzidas para confirmar a topografia (Microscopia Confocal de Varredura à Laser – CLSM), composição química (Espectroscopia de Energia Dispersiva – EDS) e propriedades físico-químicas (Perfilometria e Molhabilidade) das amostras. Em seguida, o estudo in vivo foi conduzido utilizando ratos Wistar (n = 27) e um protocolo de indução da diabetes mellitus pela administração de estreptozotocina (35mg/kg) foi empregado. Após 30 dias, os animais foram aleatoriamente distribuídos para passar por cirurgia de instalação de implantes osseointegráveis ou para confecção de fraturas femorais seguida da fixação com miniplacas do sistema 1.5mm. Os grupos experimentais consistiram em: Implante com superfície comercialmente disponível de jateamento de zircônia seguida de duplo ataque ácido (grupo ZrAC) e implante tratado por PEO-BG (grupo PEO-BG/Implante) e para as placas, foram utilizadas placas convencionalmente comercializadas, com superfície apenas usinada (grupo CONV) e placas tratadas por PEO-BG (Grupo PEO-BG/Placa). Nos períodos de 14 e 28 dias pós-operatórios, os animais foram submetidos a eutanásia e processamento laboratorial para análise histométrica e imunoistoquímica (BMP-2, OPG, RANKL e OCN), considerando o nível de significância de p<0,05 para a análise estatística. As caracterizações topográficas demonstraram que o revestimento PEO-BG foi reproduzido com sucesso, ocorrendo a efetiva incorporação dos elementos do biovidro, além de formação de uma superfície com inúmeras rugosidades, alta molhabilidade e maior área de superfície disponível. Com relação aos resultados, faz se necessário esclarecer que em decorrência da condição de diabetes mellitus ao qual todos os animais foram submetidos, houve uma alta incidência de infecção nos locais cirúrgicos nos períodos pós-operatórios, mesmo sem ocorrer deiscência de sutura e presença de contaminantes externos, com isso, as amostras de placas foram fortemente afetadas pela infecção e não apresentaram reparo tecidual. Dessa forma, não foi possível considerar tais amostras na análise e, portanto, os pontos positivos aqui elencados fazem referência apenas as amostras do estudo desenvolvido com implantes. A redução da densidade óssea mineral em decorrência da Diabete experimentalmente induzida foi comprovada a partir da análise biomecânica, onde os animais diabéticos apresentaram valores de rigidez e de força máxima significativamente menores que os animais saudáveis (p<0,05). Os resultados referentes aos implantes demonstraram maior área de osso neoformado e maior área de contato osso-implante para o grupo PEO-BG em ambos os períodos pós operatórios (14 e 28 dias) (p<0,05), com perfil inflamatório compatível com as fases do reparo tecidual. As expressões de BMP-2, RANKL, OPG e OCN corroboraram com os resultados de formação óssea e reforçaram o entendimento de que PEO-BG otimizou o reparo ósseo periimplantar. Dessa forma, o revestimento de PEO-BG apresentou efetivamente uma atividade osteoindutora e atuou melhorando as condições de reparo ósseo periimplantar, o que por sua vez tem grande potencial para favorecer a osseointegração dos implantes.
Given the promising effects of bioglass on bone repair, this study aimed to evaluate the osteoinductive potential of the PEO-BG coating synthesized via oxidation by electrolytic plasma on new bone formation in diabetic rats. For this, implants of commercially pure titanium (Ticp) were coated with PEO-BG (~ 45.0 Si, 24.5 Ca, 24.5 Na, 6.0 P; m/v %) via PEO (500 V, 1000 Hz, duty cycle of 10 %, 420 sec). Initially, surface characterizations were conducted to confirm the topography (Confocal Laser Scanning Microscopy – CLSM), chemical composition (Energy Dispersive Spectroscopy – EDS) and physical-chemical properties (Prophylometry and Wetability) of the samples. Then, the in vivo study was conducted using Wistar rats (n = 27) and a protocol of induction of diabetes mellitus by administering streptozotocin (35mg/kg) was applied. After 30 days, the animals were randomly assigned to undergo surgery to implants placement or create femoral fractures, followed by fixation with miniplates of the 1.5mm system. The experimental groups were: Implant with commercially available surface of zirconia blasting followed by double acid etching (ZrAC group) and implant treated with PEO-BG (PEO-BG/Implant group) and for the plates, conventionally commercialized plates were used, with only machined surface (CONV group) and PEO-BG treated surface (PEO-BG/Board group). At 14 and 28 postoperative days, the animals were euthanized and the samples were lab processing for histometric and immunohistochemical (BMP-2, OPG, RANKL, and OCN) analysis, considering the level of significance of p<0.05 for the statistical analysis. The topographical characterizations demonstrated that the PEO-BG coating was successfully reproduced, with the effective incorporation of the bioglass elements, in addition to the formation of a surface with numerous roughness, high wettability and greater available surface area. Regarding the results, it is necessary to clarify that due to the condition of diabetes mellitus to which all the animals were submitted, there was a high incidence of infection in the surgical sites in the postoperative periods, even without suture dehiscence and the presence of external contaminants. Therefore, the plate samples were strongly affected by the infection and did not show tissue repair. Thus, it was not possible to consider such samples in the analysis and the positive points listed here refer only to samples from the study developed with implants. The decreasing in mineral bone density as a result of experimentally induced diabetes was proven from the biomechanical analysis, where diabetic animals had lower values of stiffness and maximum strength significantly compared to healthy animals (P<0.05). The implants data showed a greater newly formed bone and bone-implant contact for the PEO-BG group in both postoperative periods (14 and 28 days) (P<0.05), with an inflammatory profile compatible with the stages of tissue repair. BMP-2, RANKL, OPG and OCN immunolabeling corroborated the bone formation results and reinforced the understanding that PEO-BG optimized peri-implant bone repair. Microtomographic analysis demonstrated a significantly superior bone volume and percentage pattern for PEO-BG, as well as superior bone quality parameters. Thus, the PEO-BG coating effectively presented an osteoinductive activity and acted to improve the conditions of peri-implant bone repair, which it has great potential to favor the osseointegration of implants.
Given the promising effects of bioglass on bone repair, this study aimed to evaluate the osteoinductive potential of the PEO-BG coating synthesized via oxidation by electrolytic plasma on new bone formation in diabetic rats. For this, implants of commercially pure titanium (Ticp) were coated with PEO-BG (~ 45.0 Si, 24.5 Ca, 24.5 Na, 6.0 P; m/v %) via PEO (500 V, 1000 Hz, duty cycle of 10 %, 420 sec). Initially, surface characterizations were conducted to confirm the topography (Confocal Laser Scanning Microscopy – CLSM), chemical composition (Energy Dispersive Spectroscopy – EDS) and physical-chemical properties (Prophylometry and Wetability) of the samples. Then, the in vivo study was conducted using Wistar rats (n = 27) and a protocol of induction of diabetes mellitus by administering streptozotocin (35mg/kg) was applied. After 30 days, the animals were randomly assigned to undergo surgery to implants placement or create femoral fractures, followed by fixation with miniplates of the 1.5mm system. The experimental groups were: Implant with commercially available surface of zirconia blasting followed by double acid etching (ZrAC group) and implant treated with PEO-BG (PEO-BG/Implant group) and for the plates, conventionally commercialized plates were used, with only machined surface (CONV group) and PEO-BG treated surface (PEO-BG/Board group). At 14 and 28 postoperative days, the animals were euthanized and the samples were lab processing for histometric and immunohistochemical (BMP-2, OPG, RANKL, and OCN) analysis, considering the level of significance of p<0.05 for the statistical analysis. The topographical characterizations demonstrated that the PEO-BG coating was successfully reproduced, with the effective incorporation of the bioglass elements, in addition to the formation of a surface with numerous roughness, high wettability and greater available surface area. Regarding the results, it is necessary to clarify that due to the condition of diabetes mellitus to which all the animals were submitted, there was a high incidence of infection in the surgical sites in the postoperative periods, even without suture dehiscence and the presence of external contaminants. Therefore, the plate samples were strongly affected by the infection and did not show tissue repair. Thus, it was not possible to consider such samples in the analysis and the positive points listed here refer only to samples from the study developed with implants. The decreasing in mineral bone density as a result of experimentally induced diabetes was proven from the biomechanical analysis, where diabetic animals had lower values of stiffness and maximum strength significantly compared to healthy animals (P<0.05). The implants data showed a greater newly formed bone and bone-implant contact for the PEO-BG group in both postoperative periods (14 and 28 days) (P<0.05), with an inflammatory profile compatible with the stages of tissue repair. BMP-2, RANKL, OPG and OCN immunolabeling corroborated the bone formation results and reinforced the understanding that PEO-BG optimized peri-implant bone repair. Microtomographic analysis demonstrated a significantly superior bone volume and percentage pattern for PEO-BG, as well as superior bone quality parameters. Thus, the PEO-BG coating effectively presented an osteoinductive activity and acted to improve the conditions of peri-implant bone repair, which it has great potential to favor the osseointegration of implants.
Descrição
Palavras-chave
Regeneração óssea, Implantes dentários, Materiais biomédicos, Dental implants