CAD/CAM monolithic materials: wear resistance and abrasiveness, and the effect of grinding and polishing on their roughness and fracture resistance.
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2019-03-14
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Universidade Estadual Paulista (Unesp)
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Esta tese consiste em dois estudos, ambos investigando materiais monolíticos fresados por tecnologia CAD-CAM. Primeiro estudo. Objetivo. A resistência ao desgaste e abrasividade do Lava Ultimate, Vita Enamic, Vita Suprinity, IPS e.max CAD e Lava Plus, bem como algumas propriedades que podem estar relacionadas, foram analisadas. Métodos. Espécimes desses materiais tiveram sua rugosidade, dureza e coeficiente de atrito avaliados, respectivamente, em microscópio confocal, microdurômetro e tribômetro. O teste de desgaste conhecido como “2-body”, no qual os materiais atuaram como abrasivos e, juntamente com o esmalte bovino, também como antagonistas, também foi realizado. A taxa de desgaste foi determinada com perfilômetro de superfície e as superfícies desgastadas foram observadas por microscopia eletrônica de varredura (MEV). Resultados. Vita Enamic e Lava Ultimate mostraram a maior rugosidade, enquanto IPS e.max CAD e Vita Suprinity, a menor. O resultado da dureza foi Lava Plus> (Vita Suprinity = IPS e.max CAD)> Vita Enamic> Lava Ultimate. O Lava Ultimate exibiu maior coeficiente de atrito do que o IPS e.max CAD e o Lava Plus. O Lava Plus e o IPS e.max CAD mostraram um potencial significativamente maior para desgastar o Lava Ultimate. Estes dois materiais, juntamente com o Vita Suprinity, foram os que mais desgastaram o esmalte e o Vita Enamic. Vita Suprinity e IPS e.max CAD promoveram o maior desgaste do Lava Plus, e o inverso também ocorreu. Vita Enamic e Lava Ultimate causaram o menor desgaste do esmalte e de todos os outros materiais avaliados. Conclusão. A resina composta nanoparticulada e a cerâmica infiltrada com polímero foram mais amigáveis ao antagonista (seja esmalte ou material) do que as vitrocerâmicas e zircônia. Cuidados devem ser tomados ao selecionar o material que irá entrar em contato principalmente com a vitrocerâmica. A dureza também deve ser considerada ao selecionar um material. Segundo estudo. Objetivo. Avaliar o efeito do desgaste e do polimento na rugosidade e resistência à fratura do Lava Ultimate, Vita Enamic, Vita Suprinity e IPS e.max CAD, submetidos ao envelhecimento mecânico. Métodos. Os discos destes materiais foram analisados quanto à rugosidade: 1) após o polimento com lixas de carbeto de silício (Lava Ultimate e Vita Enamic) ou aplicação do glaze (IPS e.max CAD e Vita Suprinity) (controle); 2) após o desgaste com ponta diamantada de 30 μm; 3) e após desgaste e polimento com o kit de polimento Ceramiste Polishers. Para a resistência à fratura, um modelo simplificado de três camadas consistindo de disco restaurador, disco de resina epóxi e um anel de aço, cimentados entre si, foi usado. Os discos tri-camada receberam as mesmos tratamentos de superfície descritos para a análise de rugosidade. Metade dos espécimes foi submetida ao envelhecimento mecânico por 1×106 ciclos. Todos os espécimes foram ensaiados até sua fratura. O módulo de Weibull foi calculado. Resultados. Entre os grupos controle, não foi encontrada diferença significativa entre o IPS e.max CAD e o Vita Suprinity e entre o Lava Ultimate e o Vita Enamic, os quais foram mais rugosos que os materiais vitrocerâmicos. Após o desgaste, esse comportamento foi mantido, com exceção do Vita Enamic, cuja rugosidade foi semelhante à do IPS e.max CAD. Após o polimento, o Vita Enamic mostrou a maior rugosidade, enquanto os outros materiais não foram estatisticamente diferentes. O IPS e.max CAD e o Vita Suprinity apresentaram a menor rugosidade nos grupos controle. Para Lava Ultimate e Vita Enamic, o polimento promoveu a menor rugosidade. O desgaste, seguido ou não por polimento, e o envelhecimento mecânico não afetaram adversamente a resistência à fratura ou a confiabilidade dos materiais. Conclusões. O polimento não recuperou a maior lisura inicial dos materiais vitrocerâmicos. A resistência à fratura não foi afetada pelo desgaste, seguido ou não por polimento, mesmo após o envelhecimento mecânico.
This thesis consists of two studies, both investigating the computer-aided design and computer-aided manufacturing (CAD-CAM) monolithic materials. First study. Aim. The wear resistance and abrasiveness of Lava Ultimate, Vita Enamic, Vita Suprinity, IPS e.max CAD, and Lava Plus, as well as some properties that might be related to, were analyzed. Methods. Specimens from these materials had their roughness, hardness, and coefficient of friction evaluated, respectively in confocal microscope, microdurometer, and tribometer. The 2-body wear test, wherein the materials acted as abraders and, together with bovine enamel, also as antagonists, was also carried out. The wear rate was determined with surface profilometer and the worn surfaces were observed by scanning electron microscopy (SEM). Results. Vita Enamic and Lava Ultimate showed the highest roughness, whereas IPS e.max CAD and Vita Suprinity, the lowest. The hardness result was Lava Plus > (Vita Suprinity=IPS e.max CAD) > Vita Enamic >Lava Ultimate. Lava Ultimate exhibited a higher coefficient of friction than IPS e.max CAD and Lava Plus. Lava Plus and IPS e.max CAD showed significantly higher potential to wear Lava Ultimate. These two materials, together with Vita Suprinity, provided the highest wear of enamel and Vita Enamic. Vita Suprinity and IPS e.max CAD exhibited the highest wear against Lava Plus, and the inverse also occurred. Vita Enamic and Lava Ultimate were among the materials that caused the lowest wear of enamel and all other evaluated materials. Conclusion. The nanofilled composite resin and polymer-infiltrated ceramic were more antagonist-friendly (whether enamel or CAD-CAM material) than glass-ceramics and zirconia. Care should be taken when selecting the material that will contact mainly with glass-ceramics. Hardness should also be considered when selecting a material. Second study. Aim. To evaluate the effect of grinding and polishing on the roughness and fracture resistance of Lava Ultimate, Vita Enamic, Vita Suprinity, and IPS e.max CAD, submitted to mechanical aging. Methods. Disks from these materials were analyzed for roughness: 1) after polishing with silicon carbide papers (Lava Ultimate and Vita Enamic) or glazing (IPS e.max CAD and Vita Suprinity) (control); 2) after grinding with 30-μm grit diamond rotary instruments; 3) and after grinding and polishing with the polishing kit Ceramiste Polishers. For fracture resistance, a simplified tri-layer model consisting of restorative disk, epoxy resin disk, and a steel ring was used. The bonded tri-layer disks received the same conditions described for the roughness analysis. Half of the specimens underwent mechanical aging for 1×106 cycles. All specimens were loaded until failure. The Weibull modulus was calculated. Results. Among the control groups, no significant difference was found between the IPS e.max CAD and Vita Suprinity and between the Lava Ultimate and Vita Enamic, which were rougher than the glass-ceramic materials. After grinding, this behavior was maintained, except for the Vita Enamic, whose roughness was similar to that of the IPS e.max CAD. After polishing, the Vita Enamic showed the highest roughness, whereas the other materials were not statistically different. IPS e.max CAD and Vita Suprinity showed the lowest roughness in the control groups. For Lava Ultimate and Vita Enamic, polishing provided the lowest roughness. Grinding followed or not by polishing, and mechanical aging, did not adversely affect fracture resistance or the reliability of the materials. Conclusions. Polishing did not recover the initial roughness of the glass-ceramic materials. Fracture resistance was not affected by grinding, followed or not by polishing, even after mechanical aging.
This thesis consists of two studies, both investigating the computer-aided design and computer-aided manufacturing (CAD-CAM) monolithic materials. First study. Aim. The wear resistance and abrasiveness of Lava Ultimate, Vita Enamic, Vita Suprinity, IPS e.max CAD, and Lava Plus, as well as some properties that might be related to, were analyzed. Methods. Specimens from these materials had their roughness, hardness, and coefficient of friction evaluated, respectively in confocal microscope, microdurometer, and tribometer. The 2-body wear test, wherein the materials acted as abraders and, together with bovine enamel, also as antagonists, was also carried out. The wear rate was determined with surface profilometer and the worn surfaces were observed by scanning electron microscopy (SEM). Results. Vita Enamic and Lava Ultimate showed the highest roughness, whereas IPS e.max CAD and Vita Suprinity, the lowest. The hardness result was Lava Plus > (Vita Suprinity=IPS e.max CAD) > Vita Enamic >Lava Ultimate. Lava Ultimate exhibited a higher coefficient of friction than IPS e.max CAD and Lava Plus. Lava Plus and IPS e.max CAD showed significantly higher potential to wear Lava Ultimate. These two materials, together with Vita Suprinity, provided the highest wear of enamel and Vita Enamic. Vita Suprinity and IPS e.max CAD exhibited the highest wear against Lava Plus, and the inverse also occurred. Vita Enamic and Lava Ultimate were among the materials that caused the lowest wear of enamel and all other evaluated materials. Conclusion. The nanofilled composite resin and polymer-infiltrated ceramic were more antagonist-friendly (whether enamel or CAD-CAM material) than glass-ceramics and zirconia. Care should be taken when selecting the material that will contact mainly with glass-ceramics. Hardness should also be considered when selecting a material. Second study. Aim. To evaluate the effect of grinding and polishing on the roughness and fracture resistance of Lava Ultimate, Vita Enamic, Vita Suprinity, and IPS e.max CAD, submitted to mechanical aging. Methods. Disks from these materials were analyzed for roughness: 1) after polishing with silicon carbide papers (Lava Ultimate and Vita Enamic) or glazing (IPS e.max CAD and Vita Suprinity) (control); 2) after grinding with 30-μm grit diamond rotary instruments; 3) and after grinding and polishing with the polishing kit Ceramiste Polishers. For fracture resistance, a simplified tri-layer model consisting of restorative disk, epoxy resin disk, and a steel ring was used. The bonded tri-layer disks received the same conditions described for the roughness analysis. Half of the specimens underwent mechanical aging for 1×106 cycles. All specimens were loaded until failure. The Weibull modulus was calculated. Results. Among the control groups, no significant difference was found between the IPS e.max CAD and Vita Suprinity and between the Lava Ultimate and Vita Enamic, which were rougher than the glass-ceramic materials. After grinding, this behavior was maintained, except for the Vita Enamic, whose roughness was similar to that of the IPS e.max CAD. After polishing, the Vita Enamic showed the highest roughness, whereas the other materials were not statistically different. IPS e.max CAD and Vita Suprinity showed the lowest roughness in the control groups. For Lava Ultimate and Vita Enamic, polishing provided the lowest roughness. Grinding followed or not by polishing, and mechanical aging, did not adversely affect fracture resistance or the reliability of the materials. Conclusions. Polishing did not recover the initial roughness of the glass-ceramic materials. Fracture resistance was not affected by grinding, followed or not by polishing, even after mechanical aging.
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CAD-CAM, Ceramics, Composite resins, Occlusal adjustment, dental Polishing, Material resistance, Projeto auxiliado por computador, Cerâmica, Resinas compostas, Ajuste oclusal, polimento dentário, Resistência dos materiais