Caracterização físico-química da superfície de vitrocerâmicas à base de metassilicato de lítio e dissilicato de lítio submetidas ao protocolo de solubilidade química
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Data
2023-02-28
Autores
Vallerini, Bruna de Freitas
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Universidade Estadual Paulista (Unesp)
Resumo
Ao longo dos anos o avanço tecnológico dos materiais vitrocerâmicos (VCs) tem desafiado os fabricantes a aprimorar as propriedades mecânicas e químicas destes materiais, além da tentativa de reduzir o tempo clínico necessário para a produção de próteses dentárias. O objetivo deste estudo foi realizar uma caracterização físico-química da superfície de VCs a base de metassilicato de lítio (ML) e dissilicato de lítio (DL) submetidas ao protocolo de solubilidade química (SQ) com o intuito de avaliar se os materiais seguem os limites estipulados pela norma ISO 6872 e como este protocolo pode afetar a superfícies destas VCs. As VCs foram divididas em sete grupos, sendo dois compostos por materiais experimentais desenvolvidos pelo Laboratório de Materiais Vítreos, que tiveram como fase majoritária o ML: ML experimental 1 (VCE1) e ML experimental 2 (VCE2); e cinco compostos por marcas comerciais à base de DL: Celtra Duo (CD), IPS e.max CAD (IEC), Straumann n!ce (SN), CEREC Tessera (TS) e VITA Suprinity (VS). Oito espécimes (14 mm x 14 mm x 1,5 mm) foram feitos para cada grupo. Para análise de SQ, os espécimes foram imersos em solução de ácido acético a 4% (16h, 80 ± 3ºC, ISO 6872) e os valores obtidos foram determinados pela diferença de massa antes e após imersão na solução divida pela área total. A rugosidade superficial foi realizada por análise de Microscopia de Força Atômica, e a caracterização química por Espectroscopia de Fotoelétrons de Raios-X, ambas as análises foram realizadas antes e após a SQ. Uma análise de lixiviação iônica da solução remanescente após SQ foi realizada por Espectrometria de Massa de Plasma Acoplado Indutivamente de Alta Resolução. As análises estatísticas foram realizadas pelo teste de Kruskal-Wallis com pós-teste de Dunn para SQ, ANOVA a dois fatores com pós-teste de Tukey para rugosidade da superfície, ANOVA a três fatores com pós-teste de Tukey para análise química, adotando-se α = 0,05, e estatística descritiva para os resultados das soluções lixiviadas. Os resultados da SQ mostraram que todos os grupos apresentaram valores dentro do estipulado pela norma (≤ 100 µg/cm2). Não houve diferença estatisticamente significativa em relação aos valores de rugosidade para as VCs antes e após imersão em ácido acético a 4%, exceto para o grupo IEC que apresentou rugosidade aumentada (p<0,001). Após o protocolo de SQ houve mudança nas porcentagens atômicas dos principais elementos constituintes das VCs (Si e Li) para todos os grupos, com uma maior lixiviação do elemento Li que para o elemento Si. Conclui-se que todos os grupos avaliados apresentam valores de SQ dentro dos limites estipulados pela Norma ISO 6872.
Over the years, the technological advancement of glass-ceramic materials (GCs) has challenged manufacturers to improve the mechanical and chemical properties of these materials, in addition to the attempt to reduce the clinical time required to produce dental prosthesis. The aim of this study was to perform a physicochemical characterization of the surface of GCs based on lithium metasilicate (LS) and lithium disilicate (LS2) subjected to chemical solubility (CS) protocol to evaluate whether the materials follow the limits stipulated by the ISO 6872 standard and how this protocol can affect the surfaces of these GCs. The GCs were divided into seven groups, two composed of experimental materials developed by the Laboratory of Vitreous Materials which had as major phase LS: LS experimental 1 (GCE1), and LS experimental 2 (GCE2); and five composed by commercial brands based on LS2: Celtra Duo (CD), IPS e.max CAD (IEC), Straumann n!ce (NS), CEREC Tessera (TS), and VITA Suprinity (VS). Eight samples were made from each group (14 mm x 14 mm x 1.5 mm). For CS analysis, samples were immersed in 4% acetic acid solution for 16h at 80 ± 3ºC (ISO 6872) and CS values were obtained by calculating the difference in mass before and after immersion in the solution divided by the total area. Surface roughness characterization was performed by Atomic Force Microscopy (AFM) analysis, and chemical characterization by X-Ray Photoelectron Spectroscopy (XPS), both analyzes were performed before and after CS. An analysis of ionic leaching in the remaining solution after CS was performed by High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Statistical analyzes were Kruskal-Wallis test with Dunn post-hoc test for CS, Two-Way ANOVA with Tukey post hoc test for surface roughness, Three-Way ANOVA with Tukey post hoc test for XPS, all analyses with α =0.05, and descriptive statistics for the values obtained by the HR-ICP-MS. Results of CS showed all groups presented values within than stipulated by the standard (≤ 100 µg/cm2). AFM showed no statistically significant difference in relation to roughness values for GCs before and after immersion in 4% acetic acid, except for the IEC group which showed increased roughness (p<0.001). XPS showed that there was a change in the atomic percentages of the main constituent elements of glass-ceramics (Si, and Li), for all groups, after the CS protocol. The HR-ICP-MS showed the highest leaching for the Li element than for Si element for all groups. It was concluded that all the groups that were evaluated presented CS values within the limits stipulated by the ISO 6872 Standard.
Over the years, the technological advancement of glass-ceramic materials (GCs) has challenged manufacturers to improve the mechanical and chemical properties of these materials, in addition to the attempt to reduce the clinical time required to produce dental prosthesis. The aim of this study was to perform a physicochemical characterization of the surface of GCs based on lithium metasilicate (LS) and lithium disilicate (LS2) subjected to chemical solubility (CS) protocol to evaluate whether the materials follow the limits stipulated by the ISO 6872 standard and how this protocol can affect the surfaces of these GCs. The GCs were divided into seven groups, two composed of experimental materials developed by the Laboratory of Vitreous Materials which had as major phase LS: LS experimental 1 (GCE1), and LS experimental 2 (GCE2); and five composed by commercial brands based on LS2: Celtra Duo (CD), IPS e.max CAD (IEC), Straumann n!ce (NS), CEREC Tessera (TS), and VITA Suprinity (VS). Eight samples were made from each group (14 mm x 14 mm x 1.5 mm). For CS analysis, samples were immersed in 4% acetic acid solution for 16h at 80 ± 3ºC (ISO 6872) and CS values were obtained by calculating the difference in mass before and after immersion in the solution divided by the total area. Surface roughness characterization was performed by Atomic Force Microscopy (AFM) analysis, and chemical characterization by X-Ray Photoelectron Spectroscopy (XPS), both analyzes were performed before and after CS. An analysis of ionic leaching in the remaining solution after CS was performed by High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Statistical analyzes were Kruskal-Wallis test with Dunn post-hoc test for CS, Two-Way ANOVA with Tukey post hoc test for surface roughness, Three-Way ANOVA with Tukey post hoc test for XPS, all analyses with α =0.05, and descriptive statistics for the values obtained by the HR-ICP-MS. Results of CS showed all groups presented values within than stipulated by the standard (≤ 100 µg/cm2). AFM showed no statistically significant difference in relation to roughness values for GCs before and after immersion in 4% acetic acid, except for the IEC group which showed increased roughness (p<0.001). XPS showed that there was a change in the atomic percentages of the main constituent elements of glass-ceramics (Si, and Li), for all groups, after the CS protocol. The HR-ICP-MS showed the highest leaching for the Li element than for Si element for all groups. It was concluded that all the groups that were evaluated presented CS values within the limits stipulated by the ISO 6872 Standard.
Descrição
Palavras-chave
Cerâmicas, Solubilidade, Microscopia de força atômica, Espectroscopia fotoeletrônica, Espectrometria de massas, Ceramics, Solubility, Microscopy, atomic force, Photoelectron spectroscopy, Mass spectrometry