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Desenvolvimento dos materiais e do processo para fabrico aditivo de materiais cerâmicos aplicado à produção de coroas dentárias com gradiente de cor
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Apesar dos recentes avanços na área, a produção de coroas dentárias de zircónia com recurso às
técnicas atualmente disponíveis é ainda um processo demorado, com elevado desgaste para os equipa-
mentos utilizados e que conduz a um elevado desperdício de material. Nesta dissertação é apresentada
uma técnica alternativa que permite a obtenção de peças com gradiente de cor, reduzindo drasticamente
o material desperdiçado, recorrendo a fabrico aditivo, vulgarmente designado por impressão 3D.
O trabalho realizado poder-se-á dividir em duas vertentes, a primeira consistiu na otimização de
um sistema capaz de realizar a mistura de tintas brancas e amarelas, com recurso a análises CFD (Com-
putational Fluid Dynamics). Recorrendo a simulação numérica, foi possível analisar de que forma a
geometria e dimensões escolhidas para o elemento misturador irão afetar diferentes fatores, como a
variação de pressão.
A segunda envolveu a otimização da composição de pastas cerâmicas, com o intuito de obter
um material, pós-sinterização, com elevada densidade relativa. Para tal, foram realizados diversos testes,
recorrendo a pastas compostas essencialmente por zircónia.
Os avanços nas duas vertentes permitiram comprovar a possibilidade de realizar a impressão de
peças com gradiente de cor, recorrendo a um sistema de robocasting low-cost e a tintas cerâmicas com-
postas por hidrogel e zircónia.
Os testes realizados levam a concluir que, recorrendo aos materiais e métodos disponíveis, será
possível otimizar os diversos processos, fazendo pequenos ajustes em áreas cruciais, de forma a atingir
a impressão de coroas dentárias com gradiente de cor e com as propriedades mecânicas desejadas.
Despite recent advances in the field, the production of zirconia dental crowns using currently available techniques is still a time-consuming process, with high wear and tear on the equipment used and which leads to a high level of material waste. This dissertation presents an alternative technique for obtaining crowns with a color gradient, drastically reducing the amount of material wasted, using addi- tive manufacturing, commonly referred as 3D printing. The work carried out can be divided into two parts: The first consisted of optimizing a system capable of mixing white and yellow paints, resorting to CFD analyses. Using numerical simulation, it was possible to analyze how the chosen geometry and dimensions would affect different factors, such as pressure variation. The second involved optimizing the composition of ceramic pastes to obtain a material with a high relative density after sintering. To this end, various tests were carried out using pastes composed of zirconia. Advances in both areas show that the idea of printing parts with a color gradient using a low- cost robocasting system and ceramic inks composed of hydrogel and zirconia is plausible. The tests carried out lead to the conclusion that, using the materials and methods available, it will be possible to optimize the various processes, making small adjustments in crucial areas, to achieve the printing of dental crowns with a color gradient and with the desired mechanical properties.
Despite recent advances in the field, the production of zirconia dental crowns using currently available techniques is still a time-consuming process, with high wear and tear on the equipment used and which leads to a high level of material waste. This dissertation presents an alternative technique for obtaining crowns with a color gradient, drastically reducing the amount of material wasted, using addi- tive manufacturing, commonly referred as 3D printing. The work carried out can be divided into two parts: The first consisted of optimizing a system capable of mixing white and yellow paints, resorting to CFD analyses. Using numerical simulation, it was possible to analyze how the chosen geometry and dimensions would affect different factors, such as pressure variation. The second involved optimizing the composition of ceramic pastes to obtain a material with a high relative density after sintering. To this end, various tests were carried out using pastes composed of zirconia. Advances in both areas show that the idea of printing parts with a color gradient using a low- cost robocasting system and ceramic inks composed of hydrogel and zirconia is plausible. The tests carried out lead to the conclusion that, using the materials and methods available, it will be possible to optimize the various processes, making small adjustments in crucial areas, to achieve the printing of dental crowns with a color gradient and with the desired mechanical properties.
Descrição
Palavras-chave
Fabrico aditivo Robocasting Zircónia Coroas dentárias Gradiente de cor