Efeitos do recobrimento da zircônia por um biovidro: caracterização da superfície e avaliação de propriedades biológicas
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Data
2017-03-31
Autores
Barros, Suelen Aline de Lima [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A adição de materiais bioativos na superfície dos abutments apresenta-se como uma alternativa interessante visando a otimização do selamento marginal na interface mucosa/implante. O presente estudo teve como objetivo promover o recobrimento da zircônia (Zr) com um biovidro Biosilicato® (BS), bem como avaliar as características físicas e químicas desta superfície, e a capacidade de bioestimulação sobre fibroblastos. Inicialmente, os seguintes veículos foram testados para recobrimento com BS sobre a superfície da Zr: álcool/água, álcool/verniz, acetona/verniz, água/verniz, glaze, silano e hipromelose. Espécimes de Zr sinterizada foram tratados com as soluções de BS nos diferentes veículos (60 mg/mL). Foi aplicado 20 µL das soluções sobre os espécimes seguido de aquecimento gradual até 1100°C por 20 minutos. A superfície dos espécimes foi avaliada em MEV para análise do recobrimento com BS e a identificação dos elementos químicos foi realizada em EDX. Após análise do padrão da cobertura, o veículo álcool/água (1:1) foi selecionado para recobrimento do BS nos experimentos subsequentes. A rugosidade de superfície (Ra) foi medida em microscópio óptico confocal, enquanto ângulo de contato e energia livre de superfície (ELS) foram determinados com auxílio de goniômetro. A alteração de cor da Zr foi avaliada em espectofotômetro UV (Delta E). Todas estas análises foram realizadas nos discos de zircônia inalterados (Zr) ou tratados com BS (Zr+BS). Para as análises biológicas, fibroblastos L929 foram semeados sobre a superfície de poliestireno (PS – controle), bem como sobre os discos de Zr inalterado (controle) ou Zr+BS, sendo a proliferação (Alamar Blue) e morfologia celular (MEV) avaliadas em períodos de 1, 3, 5 e 7 dias pós-plantio. O ensaio de wound healing foi realizado para verificar a capacidade de migração celular nas diferentes superfícies 24h após realização da ferida e a síntese de colágeno (Sirius Red) foi mensurada após 7 dias de cultura sobre os espécimes. Os dados de rugosidade superficial, ângulo de contato e energia livre de superfície foram analisados pelo teste t Student independente (p < 0,05). Análises descritivas foram feitas através de imagens de MEV para caracterização da superfície e observação da morfologia celular. As análises da proliferação celular e síntese de colágeno foram realizadas através de ANOVA/Tukey, enquanto que o wound healing foi avaliado pelo teste t Student (p < 0,05). Foi possível detectar a cobertura de um filme de BS na análise em MEV/EDX nos grupos que utilizaram álcool/água, álcool/verniz, acetona/verniz, água/verniz e líquido de glaze como veículo. Nestes espécimes foi detectada a presença de microcristais compostos de Si, Na, O e Ca na superfície da Zr tratada com BS, os quais são componentes do BS. Porém, apenas com álcool/água houve um recobrimento homogêneo dos espécimes, sendo o mesmo selecionado para os demais experimentos. A rugosidade superficial, energia livre de superfície e ângulo de contato para 2 líquidos utilizados mostrou diferença entre os grupos Zr e Zr+BS. A medida da alteração de cor resultou em ∆E=1,74, o que é considerado clinicamente insignificante. O teste do Alamar Blue demonstrou aumento significativo na viabilidade das células semeadas nos discos Zr+BS em relação aos demais grupos a partir de 3 dias de cultivo e demonstrou a capacidade do BS em bioestimular células L929. As imagens em MEV corroboraram com os achados da proliferação. Aumento na capacidade de migração celular e síntese de colágeno também foram observados para as células L929 no grupo Zr+BS em relação aos demais grupos experimentais O recobrimento do BS sobre a zircônia gerou a formação de uma camada de micro-cristais de BS, a qual promoveu aumento na rugosidade superficial e na energia livre de superfície, sugerindo a formação de uma superfície anfipática, porém sem alterar a cor da zircônia. Esta superfície apresentou elevado potencial bioativo sobre a linhagem de fibroblastos L929.
The addition of bioactive materials to the surface of the abutments is an interesting alternative for the optimization of marginal sealing at the mucosal/implant interface. The aim of the present study was to promote the coating of Biosilicate ® (BS) bioglass on the zirconia (Zr) surface, as well as to evaluate the physical and chemical characteristics of this surface, and biostimulation capacity on fibroblasts. Initially, the following vehicles were tested for coating of BS on the surface of Zr: alcohol/water, alcohol/varnish, acetone/varnish, water/varnish, glaze, silane and hypromellose. Sintered Zr specimens were treated with the BS solutions in the different vehicles (60 mg/mL). Was applied 20 μL of the solutions on the specimens followed by gradual heating to 1100°C for 20 minutes to cover the zirconia. The surface of the specimens was evaluated in SEM to analyze the coating of BS and the identification of the chemical elements was performed in EDX. After analysis of the pattern, the alcohol/water vehicle (1: 1) was selected for coating of BS in subsequent experiments. Surface roughness (Ra) was measured in confocal optical microscope, while contact angle and surface free energy (ELS) were determined by goniometer. The color alteration of the Zr was evaluated in a spectrophotometer UV (Delta E). All these analyzes were carried out on unmodified zirconia discs (Zr) or treated with BS (Zr + BS). For the biological analyzes, L929 fibroblasts were seeded on the polystyrene surface (PS - control), as well as the Zr (control) or Zr + BS discs, with proliferation (Alamar Blue) and cell morphology (SEM) evaluated in periods of 1, 3, 5 and 7 days post seeding. The wound healing assay was performed to verify cell migration capacity on the different surfaces 24h after wounding, and collagen synthesis (Sirius Red) was measured after 7 days of culture on the specimens. The surface roughness, contact angle and surface free energy data were analyzed using the independent Student t test (p <0,05). Descriptive analyzes were performed using SEM images for surface characterization and cellular morphology observation. Cell proliferation and collagen synthesis analyzes were performed through ANOVA/Tukey, while the wound healing was evaluated by the Student t test (p < 0,05). It was possible to detect the coating of a BS film in the MEV/EDX analysis in the groups where alcohol/water, alcohol/varnish, acetone/varnish, water/varnish and glaze were used. In these specimens the presence of Si, Na, O and Ca microcrystals was detected on the surface of treated Zr discs with BS, which are components of BS. However, only with alcohol/water there was a homogeneous coating of the specimens, being the same selected for the others assays. The surface roughness, free surface energy and contact angle for 2 liquids used showed a difference between the Zr and Zr + BS groups. The delta E data in the Zr and Zr + BS groups showed no significant color alteration before and after the heat treatment. The Alamar Blue test demonstrated significant increase in the viability of the cells seeded on Zr + BS discs from 3 days of culture and therefore, the ability of BS to bioestimulate L929 cells in relation to the others groups. SEM images corroborated the findings of proliferation. Increased cell migration ability and collagen synthesis were also observed for L929 cells in the Zr + BS group in relation to the others experimentals groups. The BS coating on the zirconia generated the formation of a layer of BS micro-crystals, which promoted increase in surface roughness and free surface energy, suggesting the formation of an amphipathic surface, but without altering the color of the zirconia. This surface had a high bioactive potential on the L929 fibroblast lineage.
The addition of bioactive materials to the surface of the abutments is an interesting alternative for the optimization of marginal sealing at the mucosal/implant interface. The aim of the present study was to promote the coating of Biosilicate ® (BS) bioglass on the zirconia (Zr) surface, as well as to evaluate the physical and chemical characteristics of this surface, and biostimulation capacity on fibroblasts. Initially, the following vehicles were tested for coating of BS on the surface of Zr: alcohol/water, alcohol/varnish, acetone/varnish, water/varnish, glaze, silane and hypromellose. Sintered Zr specimens were treated with the BS solutions in the different vehicles (60 mg/mL). Was applied 20 μL of the solutions on the specimens followed by gradual heating to 1100°C for 20 minutes to cover the zirconia. The surface of the specimens was evaluated in SEM to analyze the coating of BS and the identification of the chemical elements was performed in EDX. After analysis of the pattern, the alcohol/water vehicle (1: 1) was selected for coating of BS in subsequent experiments. Surface roughness (Ra) was measured in confocal optical microscope, while contact angle and surface free energy (ELS) were determined by goniometer. The color alteration of the Zr was evaluated in a spectrophotometer UV (Delta E). All these analyzes were carried out on unmodified zirconia discs (Zr) or treated with BS (Zr + BS). For the biological analyzes, L929 fibroblasts were seeded on the polystyrene surface (PS - control), as well as the Zr (control) or Zr + BS discs, with proliferation (Alamar Blue) and cell morphology (SEM) evaluated in periods of 1, 3, 5 and 7 days post seeding. The wound healing assay was performed to verify cell migration capacity on the different surfaces 24h after wounding, and collagen synthesis (Sirius Red) was measured after 7 days of culture on the specimens. The surface roughness, contact angle and surface free energy data were analyzed using the independent Student t test (p <0,05). Descriptive analyzes were performed using SEM images for surface characterization and cellular morphology observation. Cell proliferation and collagen synthesis analyzes were performed through ANOVA/Tukey, while the wound healing was evaluated by the Student t test (p < 0,05). It was possible to detect the coating of a BS film in the MEV/EDX analysis in the groups where alcohol/water, alcohol/varnish, acetone/varnish, water/varnish and glaze were used. In these specimens the presence of Si, Na, O and Ca microcrystals was detected on the surface of treated Zr discs with BS, which are components of BS. However, only with alcohol/water there was a homogeneous coating of the specimens, being the same selected for the others assays. The surface roughness, free surface energy and contact angle for 2 liquids used showed a difference between the Zr and Zr + BS groups. The delta E data in the Zr and Zr + BS groups showed no significant color alteration before and after the heat treatment. The Alamar Blue test demonstrated significant increase in the viability of the cells seeded on Zr + BS discs from 3 days of culture and therefore, the ability of BS to bioestimulate L929 cells in relation to the others groups. SEM images corroborated the findings of proliferation. Increased cell migration ability and collagen synthesis were also observed for L929 cells in the Zr + BS group in relation to the others experimentals groups. The BS coating on the zirconia generated the formation of a layer of BS micro-crystals, which promoted increase in surface roughness and free surface energy, suggesting the formation of an amphipathic surface, but without altering the color of the zirconia. This surface had a high bioactive potential on the L929 fibroblast lineage.
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Palavras-chave
Propriedades físicas, Materiais biocompatíveis, Cerâmica