Influência de diferentes protocolos de queima de glaze sobre a microdureza de materiais cerâmicos CAD/CAM
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Data
2023-02-13
Autores
Santoro, Guilherme Antunes
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O sistema CAD/CAM (computer-aided design/computer-aided manufacturing) empregado na Odontologia permite confeccionar restaurações indiretas, em um curto período, cimentá-las na mesma sessão clínica, sem a intermediação do laboratório de prótese. A cerâmica é uma opção que preenche as exigências estéticas, biológicas, mecânicas e funcionais de um material restaurador e atualmente há grande variedade de blocos cerâmicos CAD/CAM com propriedades, composição e indicações distintas. Para garantir a longevidade das restaurações, a microdureza é um fator a ser considerado, devendo ser obtido equilíbrio entre resistência ao desgaste da peça e desgaste do antagonista. O objetivo deste estudo foi avaliar o efeito de diferentes protocolos de queima do glaze (convencional e estendido) sobre a microdureza de materiais restauradores cerâmicos CAD/CAM. Foram utilizados os seguintes materiais: Cerâmica Feldspática (Cerec Blocs, Dentsply Sirona); Cerâmica Feldspática reforçada por Leucita (IPS Empress CAD, Ivoclar Vivadent); Cerâmica Di-silicato de lítio (IPS e-max CAD, Ivoclar Vivadent). Os espécimes foram submetidos a diferentes protocolos de glaze: convencional (G) - aplicação seguindo as recomendações dos fabricantes; estendido (E) – protocolo estendido de glaze. A microdureza Vickers foi calculada pelo software da máquina de testes por meio da média dos comprimentos das diagonais do losango formado pela indentação. As medidas foram calculadas pela seguinte equação (Sehgal & Ito): B = γP-1/4 (C/α) 3/2. O teste ANOVA Two Way mostrou que houve diferença estatisticamente significante entre as cerâmicas estudadas (p<0,001 e F=34,15). A comparação entre os grupos (tipo de glaze) mostrou que houve diferença significante (p=0,0014 e F=11,70) e que houve interação entre os dois fatores (p<0,001 e F=79,16). Considerando o comportamento do protocolo de glaze sobre cada material individualmente, observa-se que o protocolo de glaze estendido resultou em maiores valores de microdureza para a cerâmica feldspática. Por outro lado, esse protocolo levou a resultados inferiores para leucita e di-silicato. Para o glaze convencional, a leucita apresentou maior valor médio de microdureza, estatisticamente superior aos valores dos outros materiais. Com glaze estendido, o di-silicato de lítio apresentou resultados inferiores aos outros materiais. Pode-se concluir que: o protocolo de glaze convencional ou estendido interfere na microdureza das cerâmicas CAD/CAM estudadas, sendo que a cerâmica feldspática apresentou comportamento distinto dos outros materiais, com aumento do valor médio de microdureza para o glaze estendido. Ou seja, independente do protocolo de queima do glaze e material empregado, todos os grupos mostraram valores de dureza superiores aos valores referenciados para o esmalte dentário.
The CAD/CAM (computer-aided design/computer-aided manufacturing) system used in dentistry allows the fabrication of indirect restorations, in a short period of time, cementing them in the same clinical session, without the intermediation of the prosthetic laboratory. Ceramic is an option that fulfills the aesthetic, biological, mechanical and functional requirements of a restorative material and currently there is a wide variety of CAD/CAM ceramic blocks with distinct properties, composition and indications. To ensure the longevity of restorations, microhardness is a factor to be considered, and a balance must be obtained between wear resistance of the part and wear of the antagonist. The aim of this study is to evaluate the effect of different glaze firing protocols (conventional and extended) on the microhardness of CAD/CAM ceramic restorative materials. The following materials will be used: Feldspathic ceramics (Cerec Blocs, Dentsply Sirona); Leucite-reinforced feldspathic ceramics (IPS Empress CAD, Ivoclar Vivadent); lithium disilicate ceramics (IPS e-max CAD, Ivoclar Vivadent). The specimens will be subjected to different glaze protocols: conventional (G) - application following the manufacturers' recommendations; extended (E) - extended glaze protocol. The Vickers microhardness will be calculated by the testing machine software by means of the average of the lengths of the diagonals of the rhombus formed by the indentation. The measurements will be calculated by the following equation (Sehgal & Ito): B = γP-1/4 (C/α)3/2. The Two Way ANOVA test showed that there was a statistically significant difference between the ceramics studied (p<0.001 and F=34.15). The comparison between the groups (glaze type) showed that there was a significant difference (p=0.0014 and F=11.70) and that there was interaction between the two factors (p<0.001 and F=79.16). Considering the behavior of the glaze protocol on each material individually, it was observed that the extended glaze protocol resulted in higher microhardness values for the feldspathic ceramic. On the other hand, this protocol led to lower results for leucite and di-silicate. For the conventional glaze, leucite showed the highest mean microhardness value, which was statistically higher than the values of the other materials. With extended glaze, lithium disilicate showed lower results than the other materials. It can be concluded that: the conventional or extended glaze protocol interferes with the microhardness of the CAD/CAM ceramics studied, and the feldspathic ceramic showed a different behavior from the other materials, with an increase in the mean microhardness value for the extended glaze. That is, regardless of the glaze firing protocol and the material used, all groups showed hardness values higher than the reference values for dental enamel.
The CAD/CAM (computer-aided design/computer-aided manufacturing) system used in dentistry allows the fabrication of indirect restorations, in a short period of time, cementing them in the same clinical session, without the intermediation of the prosthetic laboratory. Ceramic is an option that fulfills the aesthetic, biological, mechanical and functional requirements of a restorative material and currently there is a wide variety of CAD/CAM ceramic blocks with distinct properties, composition and indications. To ensure the longevity of restorations, microhardness is a factor to be considered, and a balance must be obtained between wear resistance of the part and wear of the antagonist. The aim of this study is to evaluate the effect of different glaze firing protocols (conventional and extended) on the microhardness of CAD/CAM ceramic restorative materials. The following materials will be used: Feldspathic ceramics (Cerec Blocs, Dentsply Sirona); Leucite-reinforced feldspathic ceramics (IPS Empress CAD, Ivoclar Vivadent); lithium disilicate ceramics (IPS e-max CAD, Ivoclar Vivadent). The specimens will be subjected to different glaze protocols: conventional (G) - application following the manufacturers' recommendations; extended (E) - extended glaze protocol. The Vickers microhardness will be calculated by the testing machine software by means of the average of the lengths of the diagonals of the rhombus formed by the indentation. The measurements will be calculated by the following equation (Sehgal & Ito): B = γP-1/4 (C/α)3/2. The Two Way ANOVA test showed that there was a statistically significant difference between the ceramics studied (p<0.001 and F=34.15). The comparison between the groups (glaze type) showed that there was a significant difference (p=0.0014 and F=11.70) and that there was interaction between the two factors (p<0.001 and F=79.16). Considering the behavior of the glaze protocol on each material individually, it was observed that the extended glaze protocol resulted in higher microhardness values for the feldspathic ceramic. On the other hand, this protocol led to lower results for leucite and di-silicate. For the conventional glaze, leucite showed the highest mean microhardness value, which was statistically higher than the values of the other materials. With extended glaze, lithium disilicate showed lower results than the other materials. It can be concluded that: the conventional or extended glaze protocol interferes with the microhardness of the CAD/CAM ceramics studied, and the feldspathic ceramic showed a different behavior from the other materials, with an increase in the mean microhardness value for the extended glaze. That is, regardless of the glaze firing protocol and the material used, all groups showed hardness values higher than the reference values for dental enamel.
Descrição
Palavras-chave
Cerâmica, Teste de dureza, Desenho assistido por computador, Ceramics, Hardness tests, Computer-aided design