Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas
Autor(a) principal: | |
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Data de Publicação: | 2017 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Manancial - Repositório Digital da UFSM |
Texto Completo: | http://repositorio.ufsm.br/handle/1/14021 |
Resumo: | This thesis evaluated an extended glaze firing (EG) versus the conventional glaze firing (G, manufacturer-recommended) for finishing of densely sintered ceramics indicated for machining in CAD-CAM (Computer Aided Design; Computer Aided Machining) systems. Initially, the effects of both firings on ceramic surface crack healing, residual stresses, optical characteristics and crystalline structure were evaluated. Rectangular specimens (≈ 14 x 12 x 1,5mm) obtained from the section of feldspathic (FEL), leucite- (LEU), lithium disilicate- (DIS), and zirconia-reinforced lithium silicatebased (ZLS) prefabricated ceramic blocks were divided into groups according to the applied firing (n=5): G, EG (15min at dwell time, following slow cooling) and C (control/no heat treatment). Defect generated by Vickers indentation was analyzed in an electronic microscope before and after firing (n=1) to evaluate its healing process. Residual stresses were determined by indentation technique. Specimen color differences (ΔE) and variations in translucency (ΔCR) were measured after firing, respectively, by CIEDE2000 method and contrast ratio. Stability of crystalline microstructure was analyzed by X-ray diffraction (n=1). Regardless of the material, EG had greater ability to heal defects when compared to G and also produced compressive residual stresses, while G generated tensile stresses. Color differences after EG were imperceptible in FEL and LEU ceramics, perceptible/acceptable for DIS, and clinically unacceptable for ZLS. G did not perceptibly change the color of the materials. After EG, ZLS ceramic was perceptibly less translucent. Crystalline phase of all the ceramics remained stable after G and EG. Therefore, in a second moment, we intended to investigate the effect of EG and G firings on the flexural fatigue strength (FFS) of LEU and DIS ceramics. For this, ceramic blocks were machined in disc-shaped specimens using CEREC inLab MC XL and were divided into six experimental groups (n=20) according to the ceramic – LEU or DIS – and the firing – G, EG or C. Specimens were submitted to fatigue using staircase test design in water (piston-on-three ball, 500.000 cycles, 20Hz and sinusoidal loading). Surface roughness of the discs was measured using a contact profilometer, before and after firing. Fracture origin was analyzed by scanning electron microscopy (SEM). Means and the standard deviation of FFS were submitted to analysis of variance (ANOVA-1 factor) and Tukey's test (α = 0.05). The most appropriate statistical tests for pared comparisons of the roughness data were selected based on normality/homoscedasticity results. For all the tested materials, EG achieved the highest FFS, statistically higher than G and C groups. The surface roughness of the LEU and DIS ceramics did not change after G and EG. Fractographic marks led to the identification of fracture originating from the tensile surface. Thus, it was concluded that the EG cycle promoted greater defect healing in relation to G, developed tolerable residual stresses, and did not alter neither the optical properties beyond the clinical threshold, nor the microstructure of the FEL, LEU and DIS ceramics; in addition, it have improved the flexural fatigue strength values for LEU and DIS machined specimens. Therefore, it seems to be a promising alternative for finishing such materials. |
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Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicasExtended glaze firing on ceramics for hard machining: crack healing and effect on the physical-mechanical propertiesCAD/CAMCarregamento cíclicoCerâmica vítreaDifratometriaDistribuição de tensõesEstabilidade de corResistência à fadigaSelamento de trincasTratamento térmicoCAD/CAMColor stabilityCrack healingCyclic loadingDiffractometryFatigue strengthGlass-ceramicsHeat treatmentStress distributionStress profileCNPQ::CIENCIAS DA SAUDE::ODONTOLOGIAThis thesis evaluated an extended glaze firing (EG) versus the conventional glaze firing (G, manufacturer-recommended) for finishing of densely sintered ceramics indicated for machining in CAD-CAM (Computer Aided Design; Computer Aided Machining) systems. Initially, the effects of both firings on ceramic surface crack healing, residual stresses, optical characteristics and crystalline structure were evaluated. Rectangular specimens (≈ 14 x 12 x 1,5mm) obtained from the section of feldspathic (FEL), leucite- (LEU), lithium disilicate- (DIS), and zirconia-reinforced lithium silicatebased (ZLS) prefabricated ceramic blocks were divided into groups according to the applied firing (n=5): G, EG (15min at dwell time, following slow cooling) and C (control/no heat treatment). Defect generated by Vickers indentation was analyzed in an electronic microscope before and after firing (n=1) to evaluate its healing process. Residual stresses were determined by indentation technique. Specimen color differences (ΔE) and variations in translucency (ΔCR) were measured after firing, respectively, by CIEDE2000 method and contrast ratio. Stability of crystalline microstructure was analyzed by X-ray diffraction (n=1). Regardless of the material, EG had greater ability to heal defects when compared to G and also produced compressive residual stresses, while G generated tensile stresses. Color differences after EG were imperceptible in FEL and LEU ceramics, perceptible/acceptable for DIS, and clinically unacceptable for ZLS. G did not perceptibly change the color of the materials. After EG, ZLS ceramic was perceptibly less translucent. Crystalline phase of all the ceramics remained stable after G and EG. Therefore, in a second moment, we intended to investigate the effect of EG and G firings on the flexural fatigue strength (FFS) of LEU and DIS ceramics. For this, ceramic blocks were machined in disc-shaped specimens using CEREC inLab MC XL and were divided into six experimental groups (n=20) according to the ceramic – LEU or DIS – and the firing – G, EG or C. Specimens were submitted to fatigue using staircase test design in water (piston-on-three ball, 500.000 cycles, 20Hz and sinusoidal loading). Surface roughness of the discs was measured using a contact profilometer, before and after firing. Fracture origin was analyzed by scanning electron microscopy (SEM). Means and the standard deviation of FFS were submitted to analysis of variance (ANOVA-1 factor) and Tukey's test (α = 0.05). The most appropriate statistical tests for pared comparisons of the roughness data were selected based on normality/homoscedasticity results. For all the tested materials, EG achieved the highest FFS, statistically higher than G and C groups. The surface roughness of the LEU and DIS ceramics did not change after G and EG. Fractographic marks led to the identification of fracture originating from the tensile surface. Thus, it was concluded that the EG cycle promoted greater defect healing in relation to G, developed tolerable residual stresses, and did not alter neither the optical properties beyond the clinical threshold, nor the microstructure of the FEL, LEU and DIS ceramics; in addition, it have improved the flexural fatigue strength values for LEU and DIS machined specimens. Therefore, it seems to be a promising alternative for finishing such materials.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESEsta tese avaliou empregar a queima estendida de glazeamento (GE) como alternativa à queima convencional (G, recomendada pelo fabricante) para o acabamento de cerâmicas densamente sinterizadas para usinagem em sistemas CAD-CAM (Computer Aided Design; Computer Aided Machining). Primeiramente, investigou-se o efeito de ambas as queimas na cicatrização de defeitos, tensões residuais, características ópticas e na estrutura cristalina dos materiais. Espécimes retangulares (≈ 14 x 12 x 1,5mm), obtidos da secção de blocos usináveis de cerâmicas feldspática (FEL), leucítica (LEU), à base de dissilicato de lítio (DIS) e de silicato de lítio reforçada por zircônia (SLZ), foram divididos em grupos (n=5) conforme a queima aplicada: G, GE (15min à temperatura de manutenção, seguido de resfriamento lento) e C (nenhum/controle). Defeito gerado por indentação Vickers foi analisado em microscópio eletrônico antes e após a queima (n=1) para avaliação de sua cicatrização. As tensões residuais foram determinadas pela técnica da indentação. As alterações de cor (ΔE) e de translucidez (ΔRC) dos espécimes após a queima foram mensuradas, respectivamente, pelo método CIEDE2000 e pela razão de contraste. A estabilidade da microestrutura cristalina foi analisada por difração de raios-X (n=1). Independente do material, GE teve maior capacidade de cicatrizar defeitos e produziu tensões residuais compressivas, quando comparado ao G, que gerou tensões trativas. GE promoveu alterações de cor imperceptíveis nas cerâmicas FEL e LEU, perceptíveis/aceitáveis para DIS, e clinicamente inaceitáveis para SLZ. G não modificou perceptivelmente a cor dos materiais. Após GE, SLZ ficou perceptivelmente menos translúcida. A estrutura cristalina de todas as cerâmicas permaneceu estável após G e GE. Diante disso, em um segundo momento, buscou-se averiguar o efeito de GE e G sobre a resistência flexural à fadiga (RFF) de discos de LEU e DIS usinados (CEREC inLab MC XL). Os espécimes foram divididos por material nos grupos (n=20) G, GE e C e, submetidos à ensaio de fadiga pelo teste da escada, na presença de água (piston-on-three ball, 500.000 ciclos, 20Hz e carregamento sinusoidal). A rugosidade superficial dos discos foi mensurada em perfilômetro de contato, antes e após as queimas. Análise fractográfica foi executada para identificação da origem das falhas (n=1). As médias e desvio padrão da RFF dos grupos foram submetidos à análise de variância (ANOVA-1 fator) e teste de Tukey (α=0,05). Testes estatísticos para comparações pareadas dos dados de rugosidade foram selecionados em função da normalidade/homocedasticidade dos mesmos. Para ambos os materiais, GE alcançou a maior RFF, estatisticamente superior ao G e ao grupo controle, C. A rugosidade de LEU e DIS não foi alterada após as queimas G e GE. As marcas fractográficas levaram à identificação de defeitos originários da superfície de tração. Assim, conclui-se que a queima GE: conferiu maior selamento dos defeitos em relação ao G, desenvolveu tensões residuais toleráveis, sem alterar as propriedades ópticas além do limiar clínico e modificar a microestrutura das cerâmicas FEL, LEU e DIS; e, otimizou os valores de resistência flexural à fadiga para espécimes usinados de LEU e DIS, podendo vir a ser uma alternativa viável para acabamento desses materiais.Universidade Federal de Santa MariaBrasilOdontologiaUFSMPrograma de Pós-Graduação em Ciências OdontológicasCentro de Ciências da SaúdeMay, Liliana Gresslerhttp://lattes.cnpq.br/6812578163990395Rippe, Marilia Pivettahttp://lattes.cnpq.br/3336921465345785Fraga, Sarahttp://lattes.cnpq.br/8179821009699942Wandscher, Vinicius Felipehttp://lattes.cnpq.br/5112132240623592Souza, Rodrigo Othávio de Assunção ehttp://lattes.cnpq.br/4744580649418084Aurélio, Iana Lamadrid2018-08-06T21:42:04Z2018-08-06T21:42:04Z2017-10-20info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttp://repositorio.ufsm.br/handle/1/14021porAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSM2022-06-23T14:22:11Zoai:repositorio.ufsm.br:1/14021Biblioteca Digital de Teses e Dissertaçõeshttps://repositorio.ufsm.br/ONGhttps://repositorio.ufsm.br/oai/requestatendimento.sib@ufsm.br||tedebc@gmail.comopendoar:2022-06-23T14:22:11Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false |
dc.title.none.fl_str_mv |
Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas Extended glaze firing on ceramics for hard machining: crack healing and effect on the physical-mechanical properties |
title |
Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas |
spellingShingle |
Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas Aurélio, Iana Lamadrid CAD/CAM Carregamento cíclico Cerâmica vítrea Difratometria Distribuição de tensões Estabilidade de cor Resistência à fadiga Selamento de trincas Tratamento térmico CAD/CAM Color stability Crack healing Cyclic loading Diffractometry Fatigue strength Glass-ceramics Heat treatment Stress distribution Stress profile CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA |
title_short |
Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas |
title_full |
Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas |
title_fullStr |
Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas |
title_full_unstemmed |
Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas |
title_sort |
Queima estendida de glazeamento em cerâmicas de corte duro: cicatrização de defeitos e efeito sobre as propriedades físico-mecânicas |
author |
Aurélio, Iana Lamadrid |
author_facet |
Aurélio, Iana Lamadrid |
author_role |
author |
dc.contributor.none.fl_str_mv |
May, Liliana Gressler http://lattes.cnpq.br/6812578163990395 Rippe, Marilia Pivetta http://lattes.cnpq.br/3336921465345785 Fraga, Sara http://lattes.cnpq.br/8179821009699942 Wandscher, Vinicius Felipe http://lattes.cnpq.br/5112132240623592 Souza, Rodrigo Othávio de Assunção e http://lattes.cnpq.br/4744580649418084 |
dc.contributor.author.fl_str_mv |
Aurélio, Iana Lamadrid |
dc.subject.por.fl_str_mv |
CAD/CAM Carregamento cíclico Cerâmica vítrea Difratometria Distribuição de tensões Estabilidade de cor Resistência à fadiga Selamento de trincas Tratamento térmico CAD/CAM Color stability Crack healing Cyclic loading Diffractometry Fatigue strength Glass-ceramics Heat treatment Stress distribution Stress profile CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA |
topic |
CAD/CAM Carregamento cíclico Cerâmica vítrea Difratometria Distribuição de tensões Estabilidade de cor Resistência à fadiga Selamento de trincas Tratamento térmico CAD/CAM Color stability Crack healing Cyclic loading Diffractometry Fatigue strength Glass-ceramics Heat treatment Stress distribution Stress profile CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA |
description |
This thesis evaluated an extended glaze firing (EG) versus the conventional glaze firing (G, manufacturer-recommended) for finishing of densely sintered ceramics indicated for machining in CAD-CAM (Computer Aided Design; Computer Aided Machining) systems. Initially, the effects of both firings on ceramic surface crack healing, residual stresses, optical characteristics and crystalline structure were evaluated. Rectangular specimens (≈ 14 x 12 x 1,5mm) obtained from the section of feldspathic (FEL), leucite- (LEU), lithium disilicate- (DIS), and zirconia-reinforced lithium silicatebased (ZLS) prefabricated ceramic blocks were divided into groups according to the applied firing (n=5): G, EG (15min at dwell time, following slow cooling) and C (control/no heat treatment). Defect generated by Vickers indentation was analyzed in an electronic microscope before and after firing (n=1) to evaluate its healing process. Residual stresses were determined by indentation technique. Specimen color differences (ΔE) and variations in translucency (ΔCR) were measured after firing, respectively, by CIEDE2000 method and contrast ratio. Stability of crystalline microstructure was analyzed by X-ray diffraction (n=1). Regardless of the material, EG had greater ability to heal defects when compared to G and also produced compressive residual stresses, while G generated tensile stresses. Color differences after EG were imperceptible in FEL and LEU ceramics, perceptible/acceptable for DIS, and clinically unacceptable for ZLS. G did not perceptibly change the color of the materials. After EG, ZLS ceramic was perceptibly less translucent. Crystalline phase of all the ceramics remained stable after G and EG. Therefore, in a second moment, we intended to investigate the effect of EG and G firings on the flexural fatigue strength (FFS) of LEU and DIS ceramics. For this, ceramic blocks were machined in disc-shaped specimens using CEREC inLab MC XL and were divided into six experimental groups (n=20) according to the ceramic – LEU or DIS – and the firing – G, EG or C. Specimens were submitted to fatigue using staircase test design in water (piston-on-three ball, 500.000 cycles, 20Hz and sinusoidal loading). Surface roughness of the discs was measured using a contact profilometer, before and after firing. Fracture origin was analyzed by scanning electron microscopy (SEM). Means and the standard deviation of FFS were submitted to analysis of variance (ANOVA-1 factor) and Tukey's test (α = 0.05). The most appropriate statistical tests for pared comparisons of the roughness data were selected based on normality/homoscedasticity results. For all the tested materials, EG achieved the highest FFS, statistically higher than G and C groups. The surface roughness of the LEU and DIS ceramics did not change after G and EG. Fractographic marks led to the identification of fracture originating from the tensile surface. Thus, it was concluded that the EG cycle promoted greater defect healing in relation to G, developed tolerable residual stresses, and did not alter neither the optical properties beyond the clinical threshold, nor the microstructure of the FEL, LEU and DIS ceramics; in addition, it have improved the flexural fatigue strength values for LEU and DIS machined specimens. Therefore, it seems to be a promising alternative for finishing such materials. |
publishDate |
2017 |
dc.date.none.fl_str_mv |
2017-10-20 2018-08-06T21:42:04Z 2018-08-06T21:42:04Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://repositorio.ufsm.br/handle/1/14021 |
url |
http://repositorio.ufsm.br/handle/1/14021 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.rights.driver.fl_str_mv |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal de Santa Maria Brasil Odontologia UFSM Programa de Pós-Graduação em Ciências Odontológicas Centro de Ciências da Saúde |
publisher.none.fl_str_mv |
Universidade Federal de Santa Maria Brasil Odontologia UFSM Programa de Pós-Graduação em Ciências Odontológicas Centro de Ciências da Saúde |
dc.source.none.fl_str_mv |
reponame:Manancial - Repositório Digital da UFSM instname:Universidade Federal de Santa Maria (UFSM) instacron:UFSM |
instname_str |
Universidade Federal de Santa Maria (UFSM) |
instacron_str |
UFSM |
institution |
UFSM |
reponame_str |
Manancial - Repositório Digital da UFSM |
collection |
Manancial - Repositório Digital da UFSM |
repository.name.fl_str_mv |
Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM) |
repository.mail.fl_str_mv |
atendimento.sib@ufsm.br||tedebc@gmail.com |
_version_ |
1805922150431850496 |