Influência da espessura e diferentes graus de opacidade do dissilicato de lítio no grau de conversão e resistência de união de cimentos resinosos.
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Data
2022-02-24
Autores
Queiroz, Mariana Elias [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo desse trabalho foi avaliar a influência de diferentes graus de opacidade e espessuras do dissilicato de lítio no grau de conversão de dois cimentos resinosos e na resistência de união dos mesmos à cerâmica. Duzentos e quarenta amostras cerâmicas de dissilicato de lítio (6x6 mm) foram obtidos a partir de blocos de IPS E-max CAD (Ivoclar Vivadent, Schaan, Liechtensten), nas opacidades HT (alta translucidez), LT (baixa translucidez) e MO (média opacidade), nas espessuras de 0,3 mm, 0,7 mm, 1,2mm, 1,7 mm, 2,0 mm. Para as análises do grau de conversão (n=9) e resistência de união (n=8) foram utilizados um cimento de ativação física (Variolink Esthetic LC) e um cimento dual (Multilink N). Para análise do grau de conversão, as amostras de cimento foram fotoativadas sob as amostras de cerâmica e levadas a um espectrômetro Raman confocal. Para o teste de resistência de união foram confeccionados cilindros de cimento resinoso sobre as amostras cerâmicas e submetidos ao ensaio de microcisalhamento. Os resultados mostraram que o aumento das espessuras causou diminuição no grau de conversão dos dois cimentos em todas as condições estudadas, porém só influenciou negativamente a resistência de união do cimento Variolink Esthetic LC quando unido à cerâmica na opacidade MO. Na comparação entre as opacidades, de maneira geral, a cerâmica de maior translucidez HT apresentou maiores valores de grau de conversão em comparação às outras opacidades. Já para resistência de união, em algumas espessuras as cerâmicas LT e MO apresentaram os maiores valores. O cimento dual Multilink N apresentou os maiores valores nas duas análises comparado ao cimento fotoativado Variolink Esthetic LC. Portanto, o aumento da espessura e da opacidade do material cerâmico podem promover uma diminuição no grau de conversão do cimento. A resistência de união também sofre uma diminuição com o aumento da espessura de cerâmicas mais opacas. No entanto, a maior translucidez do material não garante valores mais altos dessa mesma propriedade.
This research aims to evaluate the influence of different degrees of opacity and thicknesses of lithium disilicate on the degree of conversion of two resin cements and on their bond strength to the ceramic. Two hundred and forty lithium disilicate ceramic samples (6x6 mm) were obtained from IPS E-max CAD (Ivoclar Vivadent, Schaan, Liechtensten), in HT, LT and MO opacities, with thicknesses of 0.3 mm, 0.7 mm, 1.2 mm, 1.7 mm, 2.0 mm. For degree of conversion (n=9) and bond strength analysis (n=8) a light cured (Variolink Esthetic LC) and a dual cured resin cement (Multilink N) were used. To analyze the degree of conversion, the cement samples were light cured under the ceramic samples and taken to a confocal Raman spectrometer. For the bond strength test, resin cement cylinders were made on the ceramic samples that were later subjected to a microshear. The results showed that the increase in thickness caused a decrease on degree of conversion of both cements in all the conditions studied, but it only had an influence on bond strength of Variolink LC cement for MO ceramic. Comparing the opacities, for the degree of conversion, the most translucent ceramics had higher conversion values compared to the less translucent ones in some thicknesses. As for bond strength, in some thicknesses the LT and MO ceramics showed the highest values. The dual cement Multilink showed the highest values of conversion degree and bond strength compared to Variolink Esthetic LC light-cured cement. The Multilink dual cement showed the highest values in both analyzes compared to the Variolink LC light-cured cement. Therefore, increasing the thickness and opacity of the ceramic material can promote a decrease in the degree of cement conversion. The bond strength also suffers a decrease with increasing thickness of more opaque ceramics and the greater translucency of the material does not guarantee higher values of this same property.
This research aims to evaluate the influence of different degrees of opacity and thicknesses of lithium disilicate on the degree of conversion of two resin cements and on their bond strength to the ceramic. Two hundred and forty lithium disilicate ceramic samples (6x6 mm) were obtained from IPS E-max CAD (Ivoclar Vivadent, Schaan, Liechtensten), in HT, LT and MO opacities, with thicknesses of 0.3 mm, 0.7 mm, 1.2 mm, 1.7 mm, 2.0 mm. For degree of conversion (n=9) and bond strength analysis (n=8) a light cured (Variolink Esthetic LC) and a dual cured resin cement (Multilink N) were used. To analyze the degree of conversion, the cement samples were light cured under the ceramic samples and taken to a confocal Raman spectrometer. For the bond strength test, resin cement cylinders were made on the ceramic samples that were later subjected to a microshear. The results showed that the increase in thickness caused a decrease on degree of conversion of both cements in all the conditions studied, but it only had an influence on bond strength of Variolink LC cement for MO ceramic. Comparing the opacities, for the degree of conversion, the most translucent ceramics had higher conversion values compared to the less translucent ones in some thicknesses. As for bond strength, in some thicknesses the LT and MO ceramics showed the highest values. The dual cement Multilink showed the highest values of conversion degree and bond strength compared to Variolink Esthetic LC light-cured cement. The Multilink dual cement showed the highest values in both analyzes compared to the Variolink LC light-cured cement. Therefore, increasing the thickness and opacity of the ceramic material can promote a decrease in the degree of cement conversion. The bond strength also suffers a decrease with increasing thickness of more opaque ceramics and the greater translucency of the material does not guarantee higher values of this same property.
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Palavras-chave
Materiais dentários, Cimentos de resina, Porcelana dental, Polimerização, Dental materials