Carbon fiber: Characterization and evaluation of the inflammatory response and toxicity in rats.

This study aimed to evaluate the Carbon Fiber obtained from PAN textile and cotton fiber in their different forms of presentation: non-activated carbon fiber felt (NACFF), activated carbon fiber felt (ACFF), silver activated carbon fiber felt (Ag-ACFF), and activated carbon fiber tissue (ACFT), to obtain scaffolds as a potential material with properties related to the synthetic bone graft. Characterization tests performed: surface wettability, traction, swelling, and in vivo tests: evaluation of the inflammatory response by implanting the materials in the subcutaneous tissue of 14 Wistar rats, evaluation of collagen fibers by picrosirius red staining and assessment of toxicity in the following organs: heart, spleen, liver, and kidney. In the wettability test, NACFF and ACFT were hydrophobic (θ124° and 114°), ACFF and Ag-ACFF were hydrophilic. For maximum stress, ACFF was more resistant (2.983 ± 1.059) p < .05. In the swelling test, the Ag-ACFF and ACFF groups showed the highest absorption percentage for the PBS solution and distilled water (p < .001). The organs showed no signs of acute systemic toxicity. The implant regions showed mild to moderate inflammatory infiltrate at 7 and 21 days. Only the ACFT group did not show the maturation of type I collagen fibers in 21 days. Through the conducted analyses, the ACFT shows little potential to be indicated as a possible scaffold. Therefore NACFF, ACFF, and Ag-ACFF have the potential to be considered scaffolds due to the following characteristics presented: good absorption rate, hydrophilicity, and non-toxic.

Fibra de carbono em defeitos ósseos de tamanho crítico: estudo in vivo em ratos / Carbon fiber in critical size bone defects: an in vivo study in rats

Materiais a base de carbono têm sido utilizado em várias áreas como química, engenharia, ciência dos materiais, ciências biomédicas, entre outras. Além disso, por serem quimicamente estáveis, mecanicamente fortes, acessíveis economicamente, e biologicamente compatíveis, chamaram a atenção como material de arcabouço para a engenharia tecidual óssea. Assim, o presente estudo teve como objetivo principal avaliar a fibra de carbono obtida a partir de fibra PAN têxtil, nas suas diferentes formas, com vistas à obtenção de scaffolds como potencial enxerto ósseo sintético. Foram utilizados 34 ratos adultos (Rattus norvegicus, variação albinus, Wistar), e realizados dois defeitos ósseos críticos na calvária de cada animal com 5 mm de diâmetro. Vinte e quatro animais foram divididos aleatoriamente em 4 grupos: Defeito ósseo + coágulo sanguíneo, Defeito ósseo + Feltro Fibra de Carbono Não Ativado (FFCNA), Defeito ósseo + Feltro Fibra de Carbono Ativado (FFCA), Defeito ósseo + Feltro Fibra de Carbono Ativado com Prata (FFCAAg), e foram observados por períodos distintos de 15 e 60 dias para análise histomorfométrica e micro CT. Dez animais foram divididos aleatoriamente nos mesmos 4 grupos para aplicação de marcadores fluorocromáticos e análise de aposição mineral (em andamento). Após o período de observação dos subgrupos, os animais foram eutanasiados por sobredose de anestesia geral. Em seguida, as calvárias foram removidas para as análises. Na avaliação dos dois períodos (15 e 60 dias), o FFCNA mostrou-se melhor para os parâmetros de Área de Neoformação óssea, Área de Neoformação Lamelar e Área de Neoformação Intramembranosa. Em 60 dias, o grupo FFCNA apresentou maior volume ósseo, volume tecidual e maior número de trabéculas, mostrando-se um material sintético promissor como scaffold para regeneração óssea (AU)

Carbon based materiais have been used in some areas like chemistry, engineering, materials science, biomedical science, among others. In addition, because they are chemically stables, mecanically strongs, economically acessibles, and biologically compatibles, they have drawn attention as a scaffold material for bone tissue engineering. Thus, the present study had a main objetive to evaluate the carbon fiber obtained from textile PAN fiber, in its diferents forms, as a scaffolds potential synthetic bone. Thirty four adult rats was used (Rattus norvegicus, albinus variation, Wistar), and two critical bone defects was made with 5mm in diameter. Thenty for animals was ramdoly divided in 4 groups: Bone deffect + blood clot; Bone deffect + Unactivated Carbon Fiber Felt (FFCNA); Bone deffect + Activated Carbon Fiber Felt (FFCA); Bone deffect + Carbon Fiber Felt Activated with Silver (FFCAAg), and was observed for different periods of 15 and 60 days for histomorfometrical analisys and micro CT. Ten animals was ramdoly divided in the same four groups for aplication of fluorochromatic markers and mineral apposition analisysis (in progress). After the observation period of the subgroups, the animals was euthanized by general aneshtesia overdose. Then, the calvarias was removed for the analysis. In the evaluation of the two periods (15 and 60 days), the FFCNA was better for the parameters of Bone Neoformation Area, Lamelar Neoformation Area and Intramembranous Neoformation Area. In 60 days, the FFCNA group presented higher bone volume, tissue volume and higher number of trabeculae, showing a promising synthetic material as scaffold for bone regeneration. (AU)

Influence of different alcohol intake frequencies on alveolar bone loss in adult rats: A sem study.

BACKGROUND: Alcohol intake is associated with oral diseases and bone changes including alveolar bone loss in humans and in experimental animals. The main aim of the present study is to assess the effect of long-term alcohol intake, at different frequencies, on periodontal bone loss (PBL) in adult rats. MATERIAL AND METHODS: Thirty-six (36) rats were divided into 3 groups: Control (daily water intake, n=12), daily alcohol intake (20% ethanol, n=12), and social alcohol intake (20% ethanol twice a week, n=12). The rats were sacrificed after 90 days and their right maxillae were removed. Initially, a random portion from each group was analyzed through SEM (scanning electron microscope) to assess surface topography. Next, all pieces were dissected and stained with methylene blue 1% and photographed in stereomicroscope at 10x magnification. The PBL was assessed by measuring the distance between cement-enamel junction and alveolar bone crest. RESULTS: Results showed higher (p=0.0368) alcohol solution amount in the daily intake group than in the twice week intake one. The SEM showed qualitatively flat bone surface in the control group, the social intake group presented surface with few minor hollows, and the daily intake group evidenced increased number and diameter of wells. The comparison between groups showed higher bone loss (p<0.05) in both frequencies than in the control, but the bone loss was lower (p<0.05) in the social alcohol intake group than in the daily intake one. CONCLUSIONS: Alcohol intake may cause alveolar bone loss in periodontitis-free rats depending on the frequency. Key words:Alcohol intake, alveolar bone loss, alcohol-induced periodontitis, alcoholic rats.

Alveolar bone loss induced by alcohol consumption in rats / Perda ossea alveolar induzida por consumo de álcool em ratos

Objectives: The aim of the present study was to assess the effect of regular and constant longterm alcohol consumption on the percentage of the remaining periodontal bone support (PBS) and periodontal bone loss (PBL) in adult rats. Material and Methods: Fifty-four (54) rats were divided into 3 groups: Control (daily water intake, n=18) daily alcohol intake (20% ethanol, n=18) and social alcohol intake (20% ethanol 2x a week, n=18). The rats were treated with free-choice access to both ethanol consumption frequencies. They were euthanized after 90 days and their left mandibles were radiographed for PBS measuring. The same left mandibles were defleshed and stained. The PBL was morphometrically assessed by measuring the distance between cement-enamel junction and alveolar bone crest. Results: Did not show difference (p > 0.05) in the amount of consumed alcohol between the social and daily intake groups. Rats also evidenced lower PBS percentage and higher PBL (p<0.05) in both alcohol consumption groups in comparison to the control. Conclusion: The long-term constant and regular same amount alcohol consumption may cause alveolar bone loss and reduce the remaining periodontal bone support in adult rats. Thus, the alveolar bone loss was associated with the amount of consumed alcohol, rather than with periodicity in periodontitis-free rats (AU)

Objetivo: O objetivo do presente estudo foi avaliar o efeito do consumo regular e constante de álcool em longo prazo na porcentagem do suporte ósseo periodontal remanescente (SOP) e perda óssea periodontal (PO) em ratos adultos. Material e Métodos: Cinquenta e quatro (54) ratos foram divididos em 3 grupos: Controle (ingestão diária de água, n = 18), consumo diário de álcool (20% etanol, n = 18) e consumo social de álcool (20% etanol 2x por semana, n = 18). Os ratos foram tratados com acesso de livre escolha a ambas as frequências de consumo de etanol. Eles foram sacrificados após 90 dias e suas mandíbulas esquerdas foram radiografadas para medição do SOP. As mesmas mandíbulas esquerdas foram dissecadas e coradas. A PO foi avaliada morfometricamente medindo a distância entre a junção cimento-esmalte e a crista óssea alveolar. Resultados: Não houve diferença (p> 0,05) na quantidade de álcool consumido entre os grupos de ingestão diária e social. Os ratos também evidenciaram menor porcentagem de SOP e maior PO (p<0,05) em ambos os grupos de consumo de álcool em comparação com o controle. Conclusão: A mesma quantidade consumida constante e regular de álcool em longo prazo pode causar perda óssea alveolar e reduzir o suporte ósseo periodontal remanescente em ratos adultos. Assim, a perda óssea alveolar foi associada com a quantidade de álcool consumido, ao invés da periodicidade em ratos sem periodontite. (AU)