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Estudo in vitro da citotoxicidade de um adesivo experimental com G-IEMA
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Abstract(s)
Objetivo: Comparar a citotoxicidade de um adesivo experimental contendo G-IEMA com 2 adesivos comerciais, bem como o estudo dos monómeros que os constituem, tentando avaliar a viabilidade do dendrímero G-IEMA como possível substituto do Bis-GMA.
Métodos: Para a realização do estudo de citotoxicidade, foram criados 2 grupos experimentais, um com amostras polimerizadas e outro não polimerizadas, cada um com n=12. As amostras polimerizadas foram confecionadas através da fotopolimerização de 100μL de cada adesivo e monómero, tendo sido depois introduzidos em 5mL de meio celular, durante 24 horas. Para as amostras não polimerizadas, os adesivos e monómeros foram diluídos em etanol a 250mg/mL, e a partir daí preparadas soluções stock em meio celular a 0,125mg/mL. Utilizando uma linha celular primária de células da polpa, foram realizados os ensaios de brometo de 3-(4,5-dimetil-2-tiazolil)-2, 5-difenil-2H-tetrazólio (MTT) e iodeto de propídio (PI), após 24 horas de contacto dos extratos preparados com as células, de modo a avaliar a atividade metabólica e a indução de apoptose, respetivamente. Numa tentativa de reproduzir com maior exatidão o ambiente biológico sobre o qual os adesivos atuam, o cultivo celular foi também realizado em discos de dentina, aos quais foi efetuado o procedimento clínico de aplicação dos adesivos, e posterior ensaio de PI, após 24 horas.
Resultados: Não foram verificadas diferenças significativas entre o adesivo experimental EM2 e os adesivos comerciais. O Bis-GMA apresentou valores significativamente superiores ao G-IEMA no que diz respeito à indução de apoptose, em ambos os tipos de tratamento (p ˂ 0,001). Foi possível verificar a presença e marcação com iodeto de propídio de células da polpa nos discos de dentina. Não existiu correlação entre os ensaios de MTT e PI (r = -0,041; p = 0,659).
Conclusões: Nas condições testadas, o adesivo experimental provou não ser mais tóxico que os adesivos atualmente disponíveis no mercado, demonstrando que o G-IEMA é um possível substituto viável do Bis-GMA em sistemas adesivos, tendo adicionalmente apresentado valores inferiores de indução de apoptose. É possível cultivar com sucesso, nas Egas Moniz, células da polpa em discos de dentina. É necessária a criação de uma base de testes sistematizada para melhor avaliar os mecanismos de citotoxicidade.
Objective: To compare the cytotoxicity of an experimental adhesive containing G-IEMA with 2 commercial adhesives, as well as the study of their monomers, to assess the viability of the G-IEMA dendrimer as a possible substitute for Bis-GMA. Methods: To carry out the cytotoxicity study, 2 experimental groups were created, one with polymerized samples and the other non-polymerized, each with n=12. The polymerized samples were made by photopolymerizing 100μL of each adhesive and monomer, and then placing them in 5mL of cell medium for 24 hours. For the non-polymerized samples, the adhesives and monomers were diluted in ethanol at 250mg/mL, and from there stock solutions were prepared in cell medium at 0.125mg/mL. Using a primary cell line of pulp cells, 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) and propidium iodide (PI) assays were carried out after 24 hours of contact between the extracts and the cells, to assess metabolic activity and the induction of apoptosis, respectively. In an attempt to reproduce more accurately the biological environment on which the adhesives are used, cells were also seeded in dentin disks, and the adhesives were applied following clinical procedure, in order to perform the propidium iodite (PI) assay 24 hours later. Results: No significant differences were found between the EM2 experimental adhesive and the commercial adhesives. Bis-GMA showed significantly higher values of apoptosis induction than G-IEMA, in both conditions (p ˂ 0.001). It was possible to acess the presence and PI marking of pulp cells in the dentin disks. There was no correlation between the MTT and PI tests (r = -0.041; p = 0.659). Conclusions: Under the conditions tested, the experimental adhesive proved to be no more toxic than the adhesives currently available on the market, demonstrating that G-IEMA is a viable substitute for Bis-GMA in adhesive systems, having also showed lower apoptosis induction. Pulp cells can be successfully seeded on dentin disks at Egas Moniz School of Health and Science. It is necessary to create a systematized test base to better evaluate cytotoxicity mechanisms.
Objective: To compare the cytotoxicity of an experimental adhesive containing G-IEMA with 2 commercial adhesives, as well as the study of their monomers, to assess the viability of the G-IEMA dendrimer as a possible substitute for Bis-GMA. Methods: To carry out the cytotoxicity study, 2 experimental groups were created, one with polymerized samples and the other non-polymerized, each with n=12. The polymerized samples were made by photopolymerizing 100μL of each adhesive and monomer, and then placing them in 5mL of cell medium for 24 hours. For the non-polymerized samples, the adhesives and monomers were diluted in ethanol at 250mg/mL, and from there stock solutions were prepared in cell medium at 0.125mg/mL. Using a primary cell line of pulp cells, 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) and propidium iodide (PI) assays were carried out after 24 hours of contact between the extracts and the cells, to assess metabolic activity and the induction of apoptosis, respectively. In an attempt to reproduce more accurately the biological environment on which the adhesives are used, cells were also seeded in dentin disks, and the adhesives were applied following clinical procedure, in order to perform the propidium iodite (PI) assay 24 hours later. Results: No significant differences were found between the EM2 experimental adhesive and the commercial adhesives. Bis-GMA showed significantly higher values of apoptosis induction than G-IEMA, in both conditions (p ˂ 0.001). It was possible to acess the presence and PI marking of pulp cells in the dentin disks. There was no correlation between the MTT and PI tests (r = -0.041; p = 0.659). Conclusions: Under the conditions tested, the experimental adhesive proved to be no more toxic than the adhesives currently available on the market, demonstrating that G-IEMA is a viable substitute for Bis-GMA in adhesive systems, having also showed lower apoptosis induction. Pulp cells can be successfully seeded on dentin disks at Egas Moniz School of Health and Science. It is necessary to create a systematized test base to better evaluate cytotoxicity mechanisms.
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
G-IEMA Adesivo universal Monómeros Citotoxicidade