Nanocompósito de alumina com inclusão nonométricas de zircônia para infraestruturas de próteses odontológicas livres de metal: avaliação de prosperidades mecânicas e análise microestrutural. -
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Data
2011-07-29
Autores
Pierri, Juliano de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As próteses cerâmicas sem metal têm sido cada vez mais utilizadas em função das vantagens apresentadas, como biocompatibilidade, resistência à compressão, estabilidade de cor, radiopacidade e baixa condutibilidade térmica e elétrica. O potencial desses materiais em mimetizar os tecidos dentais também tem contribuído para aumentar sua indicação, atendendo a crescente exigência estética dos pacientes. Apesar dessas características favoráveis, percentuais consideráveis de insucesso clínico têm sido observados, demonstrando que as propriedades mecânicas dos materiais utilizados ainda precisam ser melhoradas. Uma alternativa ainda pouco explorada na odontologia é a utilização de inclusões nanométricas como reforço em matriz também cerâmica, obtendo-se os nanocompósitos cerâmicos. Assim, o objetivo do presente estudo foi avaliar as propriedades de dureza, tenacidade e limite de resistência à fadiga flexural de nanocompósito denso de matriz de alumina com inclusões nanométricas de zircônia, visando sua aplicação em infraestruturas de próteses odontológicas livres de metal. As amostras foram produzidas seguindo metodologia estabelecida em estudos anteriores, que consiste nas seguintes etapas: 1) mistura das matérias primas por meio de desaglomeração da alumina pura e da ZrO2 nanométrica em moinho de bolas convencional; 2) adição da suspensão contendo as partículas nanométricas com a alumina por gotejamento contínuo da suspensão alcóolica de ZrO2 e mistura em moinho de bolas convencional; 3) secagem dos pós no interior do moinho de bolas, sob agitação, em temperatura próxima da ambiente, com auxílio de fluxo de ar perpendicular à abertura do frasco de moagem; 4) preparo das amostras com a mistura obtida, aplicando-se prensagem uniaxial (50 MPa), seguida de prensagem isostática...
Metal free prosthesis became popular because of the advantages presented by the ceramic materials, such as biocompatibility, compressive strength, color stability, radiopacity and low thermal and electrical conductivity. The potential of these materials to mimic the dental tissues and the patient’s demand for aesthetic treatments have also contributed to their increased popularity. Despite these favorable characteristics, considerable percentage of clinical failure has been observed, demonstrating that their mechanical properties still need improvements. An alternative yet little explored in dentistry is the use of nanometric inclusions as reinforcement, resulting in ceramic nanocomposites. Thus, the objective of this study was to evaluate the hardness, toughness and flexural fatigue properties of a nanocomposite comprised of alumina matrix reinforced with nano-inclusions of zirconia, expected to be used as infrastructure for metal-free prosthesis. The samples were produced following the method established in a previous study, which consists of the following steps: 1) mixture of pure alumina and nano-ZrO2 powders in conventional ball mill, 2) addition of the suspension containing the particles with nanometric alumina suspension by continuous drip of ZrO2 and mixing in conventional ball mill, 3) drying the powder inside the ball mill, stirred at ambient temperature, with the aid of air flow perpendicular to the opening of the bottle crushing; 4) sample preparation applying a uniaxial (50 MPa), followed by isostatic pressing (200 MPa). The samples were made in prismatic form (25 X 5 X 2 mm) for flexural fatigue test (n = 30) and disc-shaped (chips) with 10 mm diameter and 5 mm thickness for testing toughness and hardness (n = 10); 5) removal of organic components added during the preparation of powders and... (Complete abstract click electronic access below)
Metal free prosthesis became popular because of the advantages presented by the ceramic materials, such as biocompatibility, compressive strength, color stability, radiopacity and low thermal and electrical conductivity. The potential of these materials to mimic the dental tissues and the patient’s demand for aesthetic treatments have also contributed to their increased popularity. Despite these favorable characteristics, considerable percentage of clinical failure has been observed, demonstrating that their mechanical properties still need improvements. An alternative yet little explored in dentistry is the use of nanometric inclusions as reinforcement, resulting in ceramic nanocomposites. Thus, the objective of this study was to evaluate the hardness, toughness and flexural fatigue properties of a nanocomposite comprised of alumina matrix reinforced with nano-inclusions of zirconia, expected to be used as infrastructure for metal-free prosthesis. The samples were produced following the method established in a previous study, which consists of the following steps: 1) mixture of pure alumina and nano-ZrO2 powders in conventional ball mill, 2) addition of the suspension containing the particles with nanometric alumina suspension by continuous drip of ZrO2 and mixing in conventional ball mill, 3) drying the powder inside the ball mill, stirred at ambient temperature, with the aid of air flow perpendicular to the opening of the bottle crushing; 4) sample preparation applying a uniaxial (50 MPa), followed by isostatic pressing (200 MPa). The samples were made in prismatic form (25 X 5 X 2 mm) for flexural fatigue test (n = 30) and disc-shaped (chips) with 10 mm diameter and 5 mm thickness for testing toughness and hardness (n = 10); 5) removal of organic components added during the preparation of powders and... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Alumina, Materiais dentários, Dental materials
Como citar
PIERRI, Juliano de. Nanocompósito de alumina com inclusão nonométricas de zircônia para infraestruturas de próteses odontológicas livres de metal: avaliação de prosperidades mecânicas e análise microestrutural. -. 2011. 171 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Odontologia de Araraquara, 2011.