Análise da distribuição de tensões em reabilitação com implantes cone morse em maxilar posterior: estudo pelo MEF 3D não linear
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Data
2016-02-16
Autores
Lemos, Cleidiel Aparecido Araujo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Este projeto teve como objetivo analisar as tensões geradas por próteses fixas unitárias e esplintadas sobre implantes cone morse, em maxilar posterior, variando o comprimento dos implantes e fixação protética, por meio do método dos elementos finitos tridimensionais não linear. Foram simulados 12 modelos tridimensionais com ajuda dos programas de desenho assistido Rhinoceros 3D 4.0 (NURBS Modeling for Windows, USA) e SolidWorks 2011 (SolidWorks Corp, USA), além do programa InVesalius (CTI, São Paulo, Brasil), utilizado para confecção da porção óssea. Cada modelo representou uma seção de osso da região posterior maxilar, na forma de um bloco de osso tipo III (cortical e esponjoso), com a presença de 3 implantes do tipo cone morse, com 4,0mm de diâmetro e com diferentes comprimentos, colocados 1mm infra-ósseo, suportando prótese de 3 elementos, com coroas metalocerâmicas. No capítulo 1 foram considerados modelos variando os sistemas de retenção (Parafusadas x cimentadas), e o fator esplintagem (próteses unitárias x próteses esplintadas), enquanto que no capítulo 2 foram considerados apenas próteses unitárias variando os sistemas de retenção (Parafadas x cimentadas) e o comprimento dos implantes (7,0mm, 8,5mm, 10mm e 11,5mm). Os desenhos tridimensionais foram exportados ao programa de pré e pós processamento FEMAP v.11.0 (Siemens Product Lifecycle Management Software Inc. USA) para geração da malha, restrições e aplicação de uma carga de 400N axial e 200N oblíqua (45°), nas vertentes internas da coroa. A análise foi realizada no programa de elementos finitos NEiNastran 11 (Noran Engineering, Inc., EUA) e os resultados foram visualizados através de mapas de tensão von Mises e Tensão Máxima Principal individualizados em cada modelo proposto no programa FEMAP v.11.0. Os resultados do capítulo 1 mostraram que as próteses cimentadas apresentaram comportamento biomecânico superior em comparação com as próteses parafusadas, principalmente no carregamento oblíquo com melhor distribuição de tensões na região de implante/componente, bem como para o tecido ósseo. A esplintagem favoreceu o compartilhamento das tensões entre os implantes/componentes de ambos os sistemas de retenção, porém, em relação ao tecido ósseo foi verificado vantagem na redução das tensões distribuídas somente nas próteses parafusadas no carregamento oblíquo. Os resultados do capítulo 2 evidenciaram que as próteses cimentadas apresentaram comportamento biomecânico superior na distribuição de tensões na região de tecido ósseo cortical em comparação com as próteses parafusadas. Os implantes curtos (7 mm) apresentaram maiores áreas de tensões de tração distribuídas na região dos implantes/componentes, e tecido ósseo, com diferença significativa nas próteses parafusadas. Assim, é possível concluir que as próteses fixas implantossuportadas cimentadas foram mais favoráveis para a distribuição de tensões na região de implante/componente, e tecido ósseo, porém, a esplintagem contribui a redução das tensões distribuídas no tecido ósseo somente nas próteses parafusadas. Os implantes curtos (7 mm) apresentaram pior comportamento biomecânico, principalmente nas próteses parafusadas.
This project aimed to evaluate the stress on single and splinted implant-supported fixed prostheses over morse taper implants in the posterior region of the maxilla, varying the length of the implants and prosthetic fixation, by three-dimensional nonlinear finite element method. Twelve three-dimensional models were simulated with Rhinoceros 3D 4.0 software (NURBS Modeling for Windows, USA) and SolidWorks 2011 software (SolidWorks Corp, USA). The bone portion was obtained by use of InVesalius software (CTI, São Paulo, Brasil). Each model presented a section of bone of the maxillary posterior region in the form of a type III bone block (cortical and trabecular), with the presence of three morse tapper type implants with 4,0mm in diameter and different lenghts (7,0mm, 8,5mm, 10mm, 11,5mm) placed 1mm below at cortical bone surface supporting prostheses of three elements with metal-ceramic crowns. In chapter 1 was considered models varying the fixation systems (screw-retained x cement-retained), and the splinting (single-unit prostheses x splinted prosthesis), while in Chapter 2 was considered only single-unit prostheses varying the fixation systems (screw-retained x cement-retained), and the length of the implants (7.0mm, 8.5mm, 10mm and 11.5mm). The three-dimensional models were exported to pre- and post- processing in the FEMAP v.11.0 software (Siemens Product Lifecycle Management Software Inc. USA) for mesh generation, restrictions and configuration of load of 400N axial and 200N oblique (45º) applied at each dental cusp. The analysis was performad by NEiNastran 11 software (Noran Engineering, Inc., EUA) and results were displayed using von Mises tension maps and Maximum Principal Stress tension maps that were individualized for each proposed model as necessary. The Chapter 1 results showed that cement-retained prostheses showed better biomechanical behavior compared with the screw-retained prosthesis, mainly in oblique loading in implant/component region, as well as bone tissue. The splinted crowns favored the stress distribution between the implants/components in the both fixation systems. However, it was found advantage in reducing tensions only in screw-retained prostheses in the oblique loading in relation to bone tissue analysis. The results of Chapter 2 cement-retained prostheses showed better stress distribution in the cortical bone when compared to the screw-retained prostheses. Short implants (7 mm) showed greater stress in the implants/components, and larger area of traction stresses in the cortical bone with significant difference in the screw-retained prostheses. Thus, it can be concluded that cement-retained prostheses were more favorable for stress distribution in implant/component region and the bone tissue. However, the splinted crowns favoring the stress distribution only in the bone tissue for screw-retained prostheses. Short implants (7 mm) showed worse biomechanical behavior, especially in screwed prostheses.
This project aimed to evaluate the stress on single and splinted implant-supported fixed prostheses over morse taper implants in the posterior region of the maxilla, varying the length of the implants and prosthetic fixation, by three-dimensional nonlinear finite element method. Twelve three-dimensional models were simulated with Rhinoceros 3D 4.0 software (NURBS Modeling for Windows, USA) and SolidWorks 2011 software (SolidWorks Corp, USA). The bone portion was obtained by use of InVesalius software (CTI, São Paulo, Brasil). Each model presented a section of bone of the maxillary posterior region in the form of a type III bone block (cortical and trabecular), with the presence of three morse tapper type implants with 4,0mm in diameter and different lenghts (7,0mm, 8,5mm, 10mm, 11,5mm) placed 1mm below at cortical bone surface supporting prostheses of three elements with metal-ceramic crowns. In chapter 1 was considered models varying the fixation systems (screw-retained x cement-retained), and the splinting (single-unit prostheses x splinted prosthesis), while in Chapter 2 was considered only single-unit prostheses varying the fixation systems (screw-retained x cement-retained), and the length of the implants (7.0mm, 8.5mm, 10mm and 11.5mm). The three-dimensional models were exported to pre- and post- processing in the FEMAP v.11.0 software (Siemens Product Lifecycle Management Software Inc. USA) for mesh generation, restrictions and configuration of load of 400N axial and 200N oblique (45º) applied at each dental cusp. The analysis was performad by NEiNastran 11 software (Noran Engineering, Inc., EUA) and results were displayed using von Mises tension maps and Maximum Principal Stress tension maps that were individualized for each proposed model as necessary. The Chapter 1 results showed that cement-retained prostheses showed better biomechanical behavior compared with the screw-retained prosthesis, mainly in oblique loading in implant/component region, as well as bone tissue. The splinted crowns favored the stress distribution between the implants/components in the both fixation systems. However, it was found advantage in reducing tensions only in screw-retained prostheses in the oblique loading in relation to bone tissue analysis. The results of Chapter 2 cement-retained prostheses showed better stress distribution in the cortical bone when compared to the screw-retained prostheses. Short implants (7 mm) showed greater stress in the implants/components, and larger area of traction stresses in the cortical bone with significant difference in the screw-retained prostheses. Thus, it can be concluded that cement-retained prostheses were more favorable for stress distribution in implant/component region and the bone tissue. However, the splinted crowns favoring the stress distribution only in the bone tissue for screw-retained prostheses. Short implants (7 mm) showed worse biomechanical behavior, especially in screwed prostheses.
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Palavras-chave
Prótese dentária, Implantes dentários, Análise de elementos finitos, Dental prosthesis, Dental implants, Finite elemente analysis