Alterações ópticas, superficiais e mecânicas em cerâmicas vítreas CAD/CAM após desgaste erosivo-abrasivo e repolimento: estudo in vitro
Carregando...
Data
2021-09-03
Autores
Silva, Aryvelto Miranda
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
O desgaste erosivo-abrasivo pode causar danos a materiais restauradores de matriz resinosa ou cerâmica e a literatura permanece escassa sobre condutas para o manejo reparador destes danos. O objetivo deste estudo in vitro foi avaliar o efeito do desgaste erosivo-abrasivo e repolimento dental sobre algumas propriedades ópticas, superficiais e mecânicas de cerâmicas CAD/CAM. Discos (ꝋ 12mm; 1.2mm – ISO 6872) de três cerâmicas CAD/CAM [Vitrocerâmica reforçada com dissilicato de lítio (DL) - IPS e.max CAD, Ivoclar Vivadent; Cerâmica feldspática (FE) - CEREC Blocs, Dentsply Sirona; Vitrocerâmica reforçada com leucita (LE) - IPS Empress CAD, Ivoclar Vivadent] foram obtidos e avaliados em três condições de superfície distintas (após polimento, desgaste erosivo-abrasivo e repolimento). Os procedimentos de polimento e repolimento foram realizados utilizando o Kit de Polimento Ceramisté. O desgaste erosivo/abrasivo correspondente a 3 anos de ambiente oral foi realizado com imersão em ácido gástrico simulado por 30 horas em uma incubadora a 37ºC e 400000 ciclos de escovação simulada. Dados de cor no sistema CIELab obtidos com espectrofotômetro foram utilizados para quantificar alteração de cor (∆Eab e ∆E00), parâmetros de translucidez (PT) e de opalescência (PO) e razão de contraste (RC). Alterações na rugosidade superficial e microdureza foram obtidos com perfilômetro de contato e microdurômetro com indentador Vickers, respectivamente. O teste de resistência à flexão biaxial (RF) foi conduzido em Máquina de Ensaios Universais, até a ocorrência de fratura. Análise de dados (α = 0.05) incluiu Análises de Variância (ANOVA) a dois fatores para medidas repetidas e testes de Bonferroni, ANOVA one-way e teste de Tukey, e teste T de Student para medidas repetidas. Análise de Weibull também foi realizada. Após o repolimento, alterações de cor atingiram limiares perceptíveis (∆Eab) e clinicamente inaceitáveis (∆E00) apenas para FE. Em um mesmo material, PT e RC não foram alterados significativamente após o desgaste erosivo-abrasivo e o repolimento. O PO para todos os materiais, independente da condição de superfície, foram similares. O repolimento reduziu a rugosidade provocada pelo desgaste erosivo-abrasivo em todos os materiais, revertendo a degradação ao padrão de rugosidade após o polimento para a cerâmica reforçada por dissilicato de lítio. O repolimento após desgaste erosivo-abrasivo promoveu, de maneira similar para todos os materiais, redução significativa na microdureza Vickers. O repolimento após degaste erosivo-abrasivo reduziu a resistência à flexão de todas as cerâmicas avaliadas, e redução significativa foi observada após o desgaste erosivo-abrasivo apenas para DL. Em conclusão, a cerâmica feldspática parece ser a cerâmica mais suscetível a alterações pelo desgaste erosivo-abrasivo. O repolimento tem potencial limitado em reverter a alteração de cor e nenhum efeito sobre as demais propriedades ópticas avaliadas neste estudo, independente do material. Além disso, o repolimento após desgaste erosivo-abrasivo promove redução na microdureza e na resistência à flexão de todos os materiais cerâmicos avaliados neste estudo.
Erosive-abrasive wear can cause damage to resinous or ceramic matrix restorative materials, and the literature on approaches for the repair management of these damages remains scarce. The aim of this in vitro study was to evaluate the effect of erosive-abrasive wear and dental repolishing on some optical, surface, and mechanical properties of CAD/CAM ceramics. Discs (ꝋ 12mm; 1.2mm – ISO 6872) of three CAD/CAM ceramics [Lithium disilicate (LD) reinforced glass-ceramic - IPS e.max CAD, Ivoclar Vivadent; Feldspathic ceramics (FE) - CEREC Blocs, Dentsply Sirona; Leucite-reinforced glass-ceramic (LE) - IPS Empress CAD, Ivoclar Vivadent] were obtained and evaluated under three different surface conditions (after polishing, erosive-abrasive wear, and repolishing). Polishing and re-polishing procedures were performed using the Ceramisté Polishing Kit. Erosive/abrasive wear corresponding to 3 years of oral environment was performed with immersion in simulated gastric acid for 30 hours in an incubator at 37ºC and 400000 simulated brushing cycles. Color data in the CIELab system obtained with a spectrophotometer were used to quantify color change (∆Eab and ∆E00), translucency (PT), and opalescence (PO) parameters and contrast ratio (RC). Changes in surface roughness and microhardness were obtained with a contact profilometer and microdurometer with a Vickers indenter, respectively. A biaxial flexure strength test was carried out in a Universal Testing Machine until the occurrence of fracture. Data analysis (α = 0.05) included two-way ANOVA for repeated measures and Bonferroni tests, one-way ANOVA and Tukey test, and Student's t-test for repeated measures. Weibull analysis was also performed. After repolishing, color changes reached perceptible (∆Eab) and clinically unacceptable (∆E00) thresholds only for FE. In the same material, PT and RC were not significantly changed after erosive-abrasive wear and repolishing. The PO for all materials, regardless of surface condition, were similar. Repolishing reduced the roughness caused by erosive-abrasive wear in all materials, reversing the degradation to the roughness pattern after polishing for ceramic reinforced by lithium disilicate. Repolishing after erosive-abrasive wear promoted, in a comparable way for all materials, a significant reduction in Vickers microhardness. Repolishing after abrasive-erosive wear reduced the flexural strength of all ceramics evaluated, and a significant reduction was observed after abrasive-erosive wear only for LD. In conclusion, feldspathic ceramic is the ceramic most susceptible to alterations due to erosive-abrasive wear. Repolish has limited potential to reverse the color change and has no effect on the other optical properties evaluated in this study, regardless of material. In addition, repolishing after erosive-abrasive wear promotes a reduction in microhardness and flexural strength of all ceramic materials evaluated in this study.
Erosive-abrasive wear can cause damage to resinous or ceramic matrix restorative materials, and the literature on approaches for the repair management of these damages remains scarce. The aim of this in vitro study was to evaluate the effect of erosive-abrasive wear and dental repolishing on some optical, surface, and mechanical properties of CAD/CAM ceramics. Discs (ꝋ 12mm; 1.2mm – ISO 6872) of three CAD/CAM ceramics [Lithium disilicate (LD) reinforced glass-ceramic - IPS e.max CAD, Ivoclar Vivadent; Feldspathic ceramics (FE) - CEREC Blocs, Dentsply Sirona; Leucite-reinforced glass-ceramic (LE) - IPS Empress CAD, Ivoclar Vivadent] were obtained and evaluated under three different surface conditions (after polishing, erosive-abrasive wear, and repolishing). Polishing and re-polishing procedures were performed using the Ceramisté Polishing Kit. Erosive/abrasive wear corresponding to 3 years of oral environment was performed with immersion in simulated gastric acid for 30 hours in an incubator at 37ºC and 400000 simulated brushing cycles. Color data in the CIELab system obtained with a spectrophotometer were used to quantify color change (∆Eab and ∆E00), translucency (PT), and opalescence (PO) parameters and contrast ratio (RC). Changes in surface roughness and microhardness were obtained with a contact profilometer and microdurometer with a Vickers indenter, respectively. A biaxial flexure strength test was carried out in a Universal Testing Machine until the occurrence of fracture. Data analysis (α = 0.05) included two-way ANOVA for repeated measures and Bonferroni tests, one-way ANOVA and Tukey test, and Student's t-test for repeated measures. Weibull analysis was also performed. After repolishing, color changes reached perceptible (∆Eab) and clinically unacceptable (∆E00) thresholds only for FE. In the same material, PT and RC were not significantly changed after erosive-abrasive wear and repolishing. The PO for all materials, regardless of surface condition, were similar. Repolishing reduced the roughness caused by erosive-abrasive wear in all materials, reversing the degradation to the roughness pattern after polishing for ceramic reinforced by lithium disilicate. Repolishing after erosive-abrasive wear promoted, in a comparable way for all materials, a significant reduction in Vickers microhardness. Repolishing after abrasive-erosive wear reduced the flexural strength of all ceramics evaluated, and a significant reduction was observed after abrasive-erosive wear only for LD. In conclusion, feldspathic ceramic is the ceramic most susceptible to alterations due to erosive-abrasive wear. Repolish has limited potential to reverse the color change and has no effect on the other optical properties evaluated in this study, regardless of material. In addition, repolishing after erosive-abrasive wear promotes a reduction in microhardness and flexural strength of all ceramic materials evaluated in this study.
Descrição
Palavras-chave
Cerâmica, Erosão dentária, Abrasão dentária, Polimento dentário, Ceramics, Tooth erosion, Dental abrasion, Dental polishing