Eficácia clareadora, citotoxicidade trans-amelodentinária e cinética de degradação de géis clareadores contendo óxido de manganês
Carregando...
Data
2020-05-06
Autores
Ribeiro, Rafael Antonio de Oliveira [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Objetivo: Avaliar a eficácia clareadora, citotoxicidade e cinética de degradação de géis clareadores contendo 10% e 35% de H2O2 ativados quimicamente com óxido de manganês (MnO). Métodos: Discos de esmalte e dentina foram manchados e então submetidos ao clareamento com os géis associados a um espessante experimental contendo ou não MnO. Como controle positivo, um gel com 35% de H2O2 foi aplicado por 45 minutos sobre o esmalte, sendo que no controle negativo nenhum tratamento foi realizado. Para determinar a melhor concentração de MnO quanto a eficácia clareadora dos géis (espectrofotômetro de reflexão-UV, sistema CIE L*a*b*), discos manchados foram clareados com géis contendo 2 mg/mL, 6 mg/mL ou 10 mg/mL do catalisador. Para análise de viabilidade celular (MTT e MEV) e estresse oxidativo, o clareamento foi realizado sobre discos manchados adaptados em câmaras pulpares artificiais, sendo os extratos (meio de cultura em contato com a dentina + componentes dos géis que se difundiram pelos discos) coletados e aplicados por 1 h sobre células MDPC-23. A quantificação de H2O2 difundido pelos discos também foi determinada (violeta leuco-cristal/peroxidase). A melhor concentração do catalisador foi utilizada para as análises de cinética de degradação. Os dados numéricos obtidos foram submetidos à análise estatística específica (ANOVA; Tukey). Resultados: Aumento da eficácia clareadora com a adição de MnO foi observado para ambas as concentrações de H2O2 nos géis. A adição do catalisador nos géis reduziu a difusão trans-amelodentinária de H2O2 residual, o estresse oxidativo e consequentemente os efeitos tóxicos dos tratamentos, independente da concentração de H2O2 presente nos produtos. Esses efeitos positivos foram mais evidentes com a incorporação de 10mg/mL de MnO aos géis clareadores, o que também aumentou significativamente a produção de radicais livres e radicais hidroxila (cinética de degradação). Conclusão: Foi possível concluir que a adição do catalisador MnO em géis clareadores com 10% e 35% de H2O2 favorece a produção de radicais livres e radical hidroxila, aumenta a eficácia clareadora dos produtos, bem como diminui o estresse oxidativo e toxicidade trans-amelodentinária sobre células pulpares.
Objective: Assess the aesthetic outcome, transenamel and transdentin toxicity as well as degradation kinetics of bleaching gels with 10% and 35% H2O2 chemically activated with manganese oxide (MnO). Methods: Enamel-dentin discs were stained and bleached with gels associated with an experimental thickener containing or not MnO. As positive and negative controls, gel with 35% H2O2 was applied on enamel for 45 minutes or no treatment was performed, respectively. To determine the best concentration of MnO (2 mg/mL, 6 mg/mL and 10 mg/mL) concerning the aesthetic outcome, the discs were stained with black tea and then bleached with the experimental gels (UV-reflecting spectrophotometer, CIE L * a *B* system). For cell viability (MTT assay) and oxidative stress analysis, the bleaching protocols were performed on discs adapted to artificial pulp chambers and the extracts (culture medium in contact with dentin surface + components of the bleaching gels that diffused across the discs) were collected and applied for 1 h on odontoblast-like MDPC-23 cells. The quantification of H2O2 diffused through the discs was also determined (leuco-crystal violet/peroxidase assay). The numerical data were submitted to specific statistical analysis (ANOVA; Tukey). Results: Increased aesthetic outcome was achieved with the addition of MnO to both concentrations of H2O2 in the bleaching gels. However, this effect was more significant for the concentration of 10 mg/mL of MnO. Disregarding the concentration of H2O2 in the bleaching gels, the addition of MnO in the composition of such products reduced significantly the transenamel and transdentinal diffusion of residual H2O2, the oxidative stress and consequently the cytotoxicity of the procedures to the pulp cells. These positive data were more evident with the addition of 10mg/mL of MnO to the bleaching gels, what also increased significantly the production of free radicals and hydroxyl radicals (degradation kinetics). Conclusion: It was possible to conclude that the production of free radicals and radical hydroxyl, enhances the aesthetic outcome, as well as reduces the oxidative stress and toxicity to pulp cells.
Objective: Assess the aesthetic outcome, transenamel and transdentin toxicity as well as degradation kinetics of bleaching gels with 10% and 35% H2O2 chemically activated with manganese oxide (MnO). Methods: Enamel-dentin discs were stained and bleached with gels associated with an experimental thickener containing or not MnO. As positive and negative controls, gel with 35% H2O2 was applied on enamel for 45 minutes or no treatment was performed, respectively. To determine the best concentration of MnO (2 mg/mL, 6 mg/mL and 10 mg/mL) concerning the aesthetic outcome, the discs were stained with black tea and then bleached with the experimental gels (UV-reflecting spectrophotometer, CIE L * a *B* system). For cell viability (MTT assay) and oxidative stress analysis, the bleaching protocols were performed on discs adapted to artificial pulp chambers and the extracts (culture medium in contact with dentin surface + components of the bleaching gels that diffused across the discs) were collected and applied for 1 h on odontoblast-like MDPC-23 cells. The quantification of H2O2 diffused through the discs was also determined (leuco-crystal violet/peroxidase assay). The numerical data were submitted to specific statistical analysis (ANOVA; Tukey). Results: Increased aesthetic outcome was achieved with the addition of MnO to both concentrations of H2O2 in the bleaching gels. However, this effect was more significant for the concentration of 10 mg/mL of MnO. Disregarding the concentration of H2O2 in the bleaching gels, the addition of MnO in the composition of such products reduced significantly the transenamel and transdentinal diffusion of residual H2O2, the oxidative stress and consequently the cytotoxicity of the procedures to the pulp cells. These positive data were more evident with the addition of 10mg/mL of MnO to the bleaching gels, what also increased significantly the production of free radicals and hydroxyl radicals (degradation kinetics). Conclusion: It was possible to conclude that the production of free radicals and radical hydroxyl, enhances the aesthetic outcome, as well as reduces the oxidative stress and toxicity to pulp cells.
Descrição
Palavras-chave
Clareamento dental, Toxicidade, Odontoblastos, Tooth bleaching, Toxicity, Odontoblasts