Comportamento mecânico de implantes curtos em função de diferentes formatos de rosca: análise por elementos finitos

Trabalho avalia o comportamento de reabilitações unitárias simuladas em região posterior de uma maxila com roscas em diferentes formatos.

AUTORES

Tania Carola Sanchez Mafla
Mestra do Centro de Pesquisas Odontológicas SLMandic.
Orcid: 0000-0002-3701-185X.

Milton Edson Miranda
Professor da pós-graduação da Faculdade de Odontologia – Centro de Pesquisas Odontológicas SLMandic.
Orcid: 0000-0002-5410-6500.

Karina Andrea Novaes Olivieri
Professora da pós-graduação da Faculdade de Odontologia – Centro de Pesquisas Odontológicas SLMandic.
Orcid: 0000-0001-8843-8901.

William Cunha Brandt
Professor da pós-graduação em Implantodontia – Unisa.
Orcid: 0000-0002-6362-0499.

RESUMO

Um dos aspectos mais importantes que influenciam o comportamento dos implantes curtos é o formato de rosca. Neste trabalho, avaliou-se, por meio de análises de elementos finitos, o comportamento de reabilitações unitárias simuladas em região posterior de uma maxila com roscas em diferentes formatos. Para isso, foram construídos modelos tridimensionais utilizando o software SolidWorks 2013 representando dois implantes curtos de 5 mm x 6 mm de conexão cone-morse, com formato de rosca triangular e quadrada, e uma coroa parafusorretida com todos os seus componentes (coroa de zircônia, pilar e parafusos), simulando um primer molar do maxilar quadrante direito. Todos os materiais no sistema osso-implante-coroa são isotrópicos, homogêneos e linearmente elásticos. No sistema coroa e implante, foi aplicada uma carga axial de 300 N. Os dados foram avaliados pelo critério de cisalhamento no osso cortical e medular, e a tensão de von Mises para os implantes e componentes protéticos. Os resultados mostraram que o formato da rosca afeta a distribuição das tensões no osso cortical e medular, sendo que o formato de rosca triangular (8,17 Mpa) apresenta um menor valor de tensão de cisalhamento no osso cortical do que a rosca quadrada (13,2 Mpa). Em relação à concentração de tensões de von Mises no implante, esta foi maior para o formato de rosca quadrada. Ambos os pilares protéticos apresentaram valores de tensão von Mises semelhantes. Também uma maior tensão foi apresentada para o parafuso de rosca triangular. O implante com formato de rosca triangular apresentou o melhor comportamento mecânico para o tecido ósseo cortical, já que apresentou uma melhor distribuição das tensões, principalmente na região coronal do implante. Esse tipo de rosca também beneficia o corte de tecido ósseo cortical e a inserção do implante.

Palavras-chave – Implantes; Biomecânica; Elementos finitos.

ABSTRACT

One of the most important aspects that influence the behavior of short implants is the thread shape. In this work, the behavior of simulated unitary rehabilitations in the posterior region of the mandible with threads of different shapes was evaluated through finite element analysis. For this purpose, three-dimensional models were constructed using SolidWorks 2013 software. These models represent two short implants of 5 mm x 6 mm of Morse Cone connection with triangular thread and square thread and a screwed crown with all its components (zirconium crown, abutment and screws), simulating a first molar of the right upper quadrant. All materials in the bone-implant-crown system are isotropic, homogeneous and linearly elastic. A 300 N axial load was applied to the crown and implant system. The data was evaluated using shear criteria in the cortical and medullary bone and the Von-Mises stress for implants and prosthetic components. The results showed that the thread shape affects the distribution of stresses in the cortical and medullary bone, since the triangular thread form (8.17 MPa) has a lower value of shear strength on the cortical bone than the square thread (13.2 MPa), respectively. About the stress concentration of Von Mises in the implant, this was greater for the square thread form; both prosthetic abutments showed similar Von Mises stress values. Also a greater tension is presented for the screw of triangular thread. The triangular screw-shaped implant presented the best mechanical behavior for the cortical bone tissue since it presented a better distribution of stresses especially in the coronal region of the implant. This type of thread also benefits when cutting of the cortical bone tissue and in the insertion of the implant.

Key words – Implants; Biomechanical; Finite elements.

Recebido em out/2021
Aprovado em nov/2021

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