Efeito do desgaste nas propriedades de superfície de uma nova vitrocerâmica de dissilicato de lítio
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Data
2017-03-17
Autores
Miotto, Larissa Natiele [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Um novo dissilicato de lítio (DL), fabricado por injeção, foi desenvolvido na Universidade Federal de São Carlos com propriedades bastante interessantes, porém previamente a utilização de novos materiais é necessária à realização de algumas caracterizações. Dentre estas análises, é pertinente avaliar as propriedades de superfície após desgaste do material visto que ajustes na infraestrutura são procedimentos rotineiramente feitos pelos cirurgiões-dentistas e que ainda não há um consenso na literatura sobre o efeito deste tipo de procedimento. Assim, o objetivo deste trabalho foi avaliar o efeito do desgaste nas propriedades de superfície de uma vitrocerâmica experimental de dissilicato de lítio (DL), comparando-o com um DL comercial, simulando um ajuste clínico em infraestrutura. Foram confeccionados discos de DL experimental e comercial (e.max Press), com dimensões de 12 mm x 1,4 mm para os grupos não submetidos ao desgaste e 12 mm x 1,5 mm para os grupos submetidos ao desgaste. Os discos (N=24) foram divididos em quatro grupos: DL experimental sem desgaste (E), DL experimental com desgaste (ED), DL comercial sem desgaste (C) e DL comercial com desgaste (CD). O desgaste (0,1mm) foi realizado em um aparelho padronizador de desgaste com pedra diamantada acoplada a um micromotor elétrico. As superfícies das amostras foram avaliadas por meio de imagens 3D, microscopia eletrônica de varredura (MEV), energia livre de superfície (ELS), análise da rugosidade média (Ra) e difração de raios X (DRX). Também foi avaliada a dureza Vickers (VH). Os dados foram analisados utilizando o software Biostat 5.1 a um nível significância de 5%. ELS e VH foram analisadas utilizando ANOVA dois fatores. Para análise da Ra utilizou-se Kruskal-Wallis seguido pelo teste de Student Newman Keuls. A mediana de Ra (μm) foi: C=1,45; CD=1,13; E=1,69 e ED=1,57 sem diferença estatisticamente significativa entre os grupos. As médias de ELS foram: C=47,1; CD=55,9; E=58,3 e ED=43,7 também sem diferença estatística. As médias de VH foram: C=571,86; CD=580,75; E=603,22 e ED=589,60 sem diferença estatisticamente significante entre marcas e tratamento. Imagens de MEV mostraram que o desgaste causa ranhuras nas superfícies, porém suaviza as superfícies como visualizado nas imagens 3D. Não ocorreu alteração da estrutura cristalina após o desgaste. De acordo com este estudo, concluiu-se que o desgaste realizado no DL pode ser realizado sem prejudicar as propriedades de superfície do DL comercial e experimental e que o DL experimental apresentou comportamento semelhante ao material comercial.
A new lithium disilicate (LD), manufactured by injection, was developed at the Federal University of São Carlos with interesting properties, but prior to new materials use it is necessary to perform some characterizations. Among these analyzes, it is pertinent to evaluate the surface properties after material grinding since core adjustments are routinely performed by dentists and there is no consensus in the literature about the effect of this type of procedure. Thus, the objective of this work was to evaluate the effect of grinding on the surface properties of an experimental lithium disilicate, comparing it with a commercial LD, simulating a clinical core adjustment. Disks of experimental and commercial LD (N=24) were made with final dimensions of 12 mm X 1.4 mm for the groups not ground and 12 mm X 1.5 mm for the groups that were ground. Disks were divided into four groups: experimental LD with no grinding (E), experimental LD with grinding (EG), commercial LD with no grinding (C) and commercial LD with grinding (CG). The grinding (0.1mm) was carried out in a standard grinding apparatus with diamond stone coupled to an electric micromotor. The surfaces of the samples were evaluated by means of 3D images, scanning electron microscopy (SEM), surface free energy (ELS), analysis of the average roughness (Ra) and X-ray diffraction (XRD). Vickers hardness (VH) was also evaluated. Data were analyzed using Biostat 5.1 software at a significant level of 5%. SFE and VH were analyzed using two-way ANOVA. For Ra analysis was used Kruskal-Wallis followed by the Student Newman Keuls test. The median of Ra (μm) were: C=1.45, CG= 1.13, E=1.69 and EG= 1.57 with no statically difference between groups. ELS means were: C= 47.1, CG= 55.9, E= 58.3 and EG= 43.7 also with no statically difference. VH means were: C=571.86, CG= 580.75, E= 603.22 and EG= 589.60 with no statically difference between brands and treatment. SEM images show that grinding causes grooves in surfaces, however smooths the surfaces as seen in 3D images. There was no change in the crystalline structure after grinding. According to this study, it was concluded that the grinding performed at LD can be performed without prejudice surface properties of commercial and experimental LD and that experimental LD exhibited similar behavior to the commercial material.
A new lithium disilicate (LD), manufactured by injection, was developed at the Federal University of São Carlos with interesting properties, but prior to new materials use it is necessary to perform some characterizations. Among these analyzes, it is pertinent to evaluate the surface properties after material grinding since core adjustments are routinely performed by dentists and there is no consensus in the literature about the effect of this type of procedure. Thus, the objective of this work was to evaluate the effect of grinding on the surface properties of an experimental lithium disilicate, comparing it with a commercial LD, simulating a clinical core adjustment. Disks of experimental and commercial LD (N=24) were made with final dimensions of 12 mm X 1.4 mm for the groups not ground and 12 mm X 1.5 mm for the groups that were ground. Disks were divided into four groups: experimental LD with no grinding (E), experimental LD with grinding (EG), commercial LD with no grinding (C) and commercial LD with grinding (CG). The grinding (0.1mm) was carried out in a standard grinding apparatus with diamond stone coupled to an electric micromotor. The surfaces of the samples were evaluated by means of 3D images, scanning electron microscopy (SEM), surface free energy (ELS), analysis of the average roughness (Ra) and X-ray diffraction (XRD). Vickers hardness (VH) was also evaluated. Data were analyzed using Biostat 5.1 software at a significant level of 5%. SFE and VH were analyzed using two-way ANOVA. For Ra analysis was used Kruskal-Wallis followed by the Student Newman Keuls test. The median of Ra (μm) were: C=1.45, CG= 1.13, E=1.69 and EG= 1.57 with no statically difference between groups. ELS means were: C= 47.1, CG= 55.9, E= 58.3 and EG= 43.7 also with no statically difference. VH means were: C=571.86, CG= 580.75, E= 603.22 and EG= 589.60 with no statically difference between brands and treatment. SEM images show that grinding causes grooves in surfaces, however smooths the surfaces as seen in 3D images. There was no change in the crystalline structure after grinding. According to this study, it was concluded that the grinding performed at LD can be performed without prejudice surface properties of commercial and experimental LD and that experimental LD exhibited similar behavior to the commercial material.
Descrição
Palavras-chave
Cerâmica, Ajuste de prótese, Dureza, Microscopia eletrônica de varredura, Ceramics, Prosthesis fitting, Hardness, Scanning electron microscopy