A firm connection of the bone-implant-fixation system is of utmost importance for patients with cranial defects. In order to improve the connection reliability, the current research focuses on finding the optimal fixation method, as well as selection of the implant manufacturing methods and the used materials. For the latter, implementation of bioactive materials such as hydroxyapatite or other calcium phosphates has also been considered in the literature. The aim of this study was to investigate the effect of gradual osseointegration on the biomechanical performance of cranial Ti6Al4V implants with a deposited HA coating as the osseointegration agent. This effect was assessed by two different computational approaches using finite element method (FEM) modeling. The values of key input parameters necessary for FEM were obtained from experimental plasma spray deposition of HA layers onto Ti6Al4V samples. Immediately upon implantation, the HA layer at the bone-implant contact area brought only a slight decrease in the values of von Mises stress in the implant and the micro-screws when compared to a non-coated counterpart; importantly, this was without any negative trade-off in other important characteristics. The major benefit of the HA coatings was manifested upon the modeled osseointegration: the results of both approaches confirmed a significant reduction of investigated parameters such as the total implant displacements (reduced from 0.050 mm to 0.012 mm and 0.002 mm while using Approach I and II, respectively) and stresses (reduced from 52 MPa to 10 MPa and 1 MPa) in the implanted components in comparison to non-coated variant. This is a very promising result for potential use of thermally sprayed HA coatings for cranial implants.

• MeSH
• analýza metodou konečných prvků MeSH
• biokompatibilní potahované materiály chemie   farmakologie   MeSH
• fosforečnany vápenaté chemie   farmakologie   MeSH
• hydroxyapatit chemie   farmakologie   MeSH
• kostní náhrady chemie   farmakologie   MeSH
• lebka diagnostické zobrazování   účinky léků   patologie   MeSH
• lidé MeSH
• osteointegrace účinky léků   fyziologie   MeSH
• protézy a implantáty MeSH
• slitiny chemie   farmakologie   MeSH
• testování materiálů MeSH
• titan chemie   farmakologie   MeSH
• zubní implantáty * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biokompatibilní potahované materiály MeSH
• fosforečnany vápenaté MeSH
• hydroxyapatit MeSH
• kostní náhrady MeSH
• slitiny MeSH
• titan MeSH
• titanium alloy (TiAl6V4) MeSH Prohlížeč
• zubní implantáty * MeSH

The paper deals with the impact of chosen geometric and material factors on maximal stresses in carotid atherosclerotic plaque calculated using patient-specific finite element models. These stresses are believed to be decisive for the plaque vulnerability but all applied models suffer from inaccuracy of input data, especially when obtained in vivo only. One hundred computational models based on ex vivo MRI are used to investigate the impact of wall thickness, MRI slice thickness, lipid core and fibrous tissue stiffness, and media anisotropy on the calculated peak plaque and peak cap stresses. The investigated factors are taken as continuous in the range based on published experimental results, only the impact of anisotropy is evaluated by comparison with a corresponding isotropic model. Design of Experiment concept is applied to assess the statistical significance of these investigated factors representing uncertainties in the input data of the model. The results show that consideration of realistic properties of arterial wall in the model is decisive for the stress evaluation; assignment of properties of fibrous tissue even to media and adventitia layers as done in some studies may induce up to eightfold overestimation of peak stress. The impact of MRI slice thickness may play a key role when local thin fibrous cap is present. Anisotropy of media layer is insignificant, and the stiffness of fibrous tissue and lipid core may become significant in some combinations.

• MeSH
• analýza metodou konečných prvků MeSH
• arteriae carotides diagnostické zobrazování   patologie   MeSH
• aterosklerotický plát diagnostické zobrazování   patologie   MeSH
• biomechanika MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mechanické jevy * MeSH
• modely kardiovaskulární MeSH
• počítačové modelování podle konkrétního pacienta * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH