Wyniki wyszukiwania - BazTech

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Assessment of stress shielding around a dental implant for variation of implant stiffness and parafunctional loading using finite element analysis

Ishak Muhammad Ikman, Daud Ruslizam, Noor Siti Noor Fazliah Mohd, Khor C.Y., Roslan Husniyati

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 3

147--159

EN

The aim of this study was to evaluate the mechanical stimuli transfer at the bone-implant interface via stress and strain energy density transfer parameters. This study also aimed to investigate the effect of different implant stiffness and parafunctional loading values on the defined mechanical stimuli transfer from the implant to the surrounding bone. Methods: A three-dimensional finite element model of two-piece threaded dental implant with internal hexagonal connection and mandibular bone block was constructed. Response surface method through face-centred central composite design was applied to examine the influence of two independent factors variables using three levels. The analysis model was fitted to a second-order polynomial equation to determine the response values. Results: The results showed that the implant stiffness was more effective than the horizontal load value in increasing the stress and strain energy density transfers. The interaction between both factors was significant in decreasing the likelihood of bone resorption. Decreasing the implant stiffness and horizontal load value led to the increased stress transfer and unexpected decrease in the strain energy density, except at the minimum level of the horizontal load. The increase in the implant stiffness and horizontal load value (up to medium level) have increased the strain energy transfer to the bone. Conclusions: The stress and strain energy density were transferred distinctively at the bone–implant interface. The role of both implant stiffness and parafunctional loading is important and should be highlighted in the preoperative treatment planning and design of dental implant.

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Biomechanical properties of hip implant with ceramics coating

Vinakurava A., Skrzat A.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2016

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z. 88 [293], nr 1

65--72

EN

In this paper the results of investigations of biomechanical properties of transplantation of hip bone with ceramic coating are present ed. The finite element analysis of the stress-strain state of the femur bone after hip replacement surgery and full recovery period are carried out. A finite element model of the femur bone is obtained on the basis of tomographic data of 36 years old male patient. A transplant stem with ceramic coating based on A400 lateralized specification was analyzed. Stresses in the intact femur and femur after arthroplasty were determined. The effect of the reduction of bone density as the result of removal of normal stresses by an implant were analyzed. The study serves as a biomechanical basis for development of artificial prostheses and for clinical hip joint replacements.

PL

W artykule przedstawiono wyniki badań właściwości biomechanicznych przeszczepu kości biodrowej z powłoką ceramiczną. Przeprowadzono analizę metodą elementów skończonych stanu naprężeń i odkształceń kości udowej po zabiegu wymiany stawu biodrowego i po pełnym okresie rekonwalescencji. Model kości udowej wykorzystany do analizy metodą elementów skończonych otrzymano na podstawie danych termograficznych 36-letniego pacjenta. Analizie poddano rdzeń przeszczepu okryty powłoką ceramiczną na podstawie specyfikacji A400. Wyznaczono naprężenia w kości udowej nienaruszonej i po endoprotezoplastyce. Analizowano wpływ zmniejszenia gęstości kości jako wyniku usunięcia naprężeń normalnych przez implant. Badania stanowią podstawę biomechaniczną do opracowywania sztucznych protez stawu biodrowego i klinicznych wymian połączenia biodrowego.

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Mechanical assessment of a hip joint stem model made of a PEEK/carbon fibre composite under compression loading

Dworak M., Błażewicz S.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 2

71--79

EN

Purpose: The aim of the work was to manufacture a composite stem model consisting of carbon fibres (CF) and polyether ether ketone (PEEK) and to perform the surface strain and stress distributions in the stem-femoral bone model under compression loading. Methods: Composite stems differing in elasticity were prepared. Three types of composite stems having different arrangements of carbon fibre reinforcements (carbon fibre roving, carbon fibre sleeves and their combinations) in the polymer matrix were made. The stems were cementless fixed in the femoral bone model channel or with the use of the polymer bone cement (PMMA). Mechanical behaviour of composite stems under compression loading was compared with a metallic stem by strain gauge measurements at different parts of stem/bone model systems. Results: The values of stresses in the proximal part of the bone model for cemented and cementless fixations of the composite stem in the femoral bone channel were higher than those noted for the metallic stem. The increase in proximal bone stress was almost similar for both types of fixation of composite stems, i.e., cemented and cementless fixed stems. Conclusions: The optimal range of mechanical stiffness, strengths and work up to fracture was obtained for composite stem made of carbon fibre sleeves and carbon fibres in the form of roving. Depending on the elasticity of the composite stem model, an increase in the stress in the proximal part of femoral bone model of up to 40% was achieved in comparison with the metallic stem.