Computer Methods in Biomechanics and Biomedical Engineering (COMPUT METHOD BIOMEC)

Publications in this journal

• Article: Estimation of ligament strains and joint moments in the ankle during a supination sprain injury.

  Feng Wei, Daniel Tik-Pui Fong, Kai-Ming Chan, Roger C Haut
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  ABSTRACT: This study presents the ankle ligament strains and ankle joint moments during an accidental injury event diagnosed as a grade I anterior talofibular ligament (ATaFL) sprain. A male athlete accidentally sprained his ankle while performing a cutting motion in a laboratory setting. The kinematic data were input to a three-dimensional rigid-body foot model for simulation analyses. Maximum strains in 20 ligaments were evaluated in simulations that investigated various combinations of the reported ankle joint motions. Temporal strains in the ATaFL and the calcaneofibular ligament (CaFL) were then compared and the three-dimensional ankle joint moments were evaluated from the model. The ATaFL and CaFL were highly strained when the inversion motion was simulated (10% for ATaFL and 12% for CaFL). These ligament strains were increased significantly when either or both plantarflexion and internal rotation motions were added in a temporal fashion (up to 20% for ATaFL and 16% for CaFL). Interestingly, at the time strain peaked in the ATaFL, the plantarflexion angle was not large but apparently important. This computational simulation study suggested that an inversion moment of approximately 23 N m plus an internal rotation moment of approximately 11 N m and a small plantarflexion moment may have generated a strain of 15-20% in the ATaFL to produce a grade I ligament injury in the athlete's ankle. This injury simulation study exhibited the potentially important roles of plantarflexion and internal rotation, when combined with a large inversion motion, to produce a grade I ATaFL injury in the ankle of this athlete.
  Computer Methods in Biomechanics and Biomedical Engineering 05/2013;
• Article: Role of differential adhesion in cell cluster evolution: from vasculogenesis to cancer metastasis.

  Jaykrishna Singh, Fazle Hussain, Paolo Decuzzi
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  ABSTRACT: Cell-cell and cell-matrix adhesions are fundamental to numerous physiological processes, including angiogenesis, tumourigenesis, metastatic spreading and wound healing. We use cellular potts model to computationally predict the organisation of cells within a 3D matrix. The energy potentials regulating cell-cell (JCC) and cell-matrix (JMC) adhesive interactions are systematically varied to represent different, biologically relevant adhesive conditions. Chemotactically induced cell migration is also addressed. Starting from a cluster of cells, variations in relative cell adhesion alone lead to different cellular patterns such as spreading of metastatic tumours and angiogenesis. The combination of low cell-cell adhesion (high JCC) and high heterotypic adhesion (low JMC) favours the fragmentation of the original cluster into multiple, smaller cell clusters (metastasis). Conversely, cellular systems exhibiting high-homotypic affinity (low JCC) preserve their original configuration, avoiding fragmentation (organogenesis). For intermediate values of JCC and JMC (i.e. JCC/JMC ∼ 1), tubular and corrugated structures form. Fully developed vascular trees are assembled only in systems in which contact-inhibited chemotaxis is activated upon cell contact. Also, the rate of secretion, diffusion and sequestration of chemotactic factors, cell deformability and motility do not significantly affect these trends. Further developments of this computational model will predict the efficacy of therapeutic interventions to modulate the diseased microenvironment by directly altering cell cohesion.
  Computer Methods in Biomechanics and Biomedical Engineering 05/2013;
• Article: Elucidating the scapulo-humeral rhythm calculation: 3D joint contribution method.

  Xavier Robert-Lachaine, Patrick Marion, Véronique Godbout, Jacinte Bleau, Mickael Begon
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  ABSTRACT: The scapulo-humeral rhythm quantifies shoulder joint coordination during arm elevation. The common method calculates a ratio of gleno-humeral (GH) elevation to scapulo-thoracic upward rotation angles. However the other rotations also contribute to arm elevation. The objective is to propose a 3D dynamic scapulo-humeral rhythm calculation method including all rotations of the shoulder joints and compare with the common method. Twenty-nine skin markers were placed on the trunk and dominant arm of 14 healthy males to measure shoulder kinematics. Two-way repeated measures ANOVAs were applied to compare the two methods of calculation of joint contributions and scapulo-humeral rhythm during arm elevation. Significant main effects (p < 0.05) were observed between methods in joint contribution angles and scapulo-humeral rhythms. A systematic overestimation of the GH contribution was observed when only using the GH elevation angle because the scapula is moved outside a vertical plane. Hence, the proposed 3D method to calculate the scapulo-humeral rhythm allows an improved functional shoulder evaluation.
  Computer Methods in Biomechanics and Biomedical Engineering 05/2013;
• Article: Combining extreme learning machines using support vector machines for breast tissue classification.

  Mohammad Reza Daliri
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  ABSTRACT: In this paper, we present a new approach for breast tissue classification using the features derived from electrical impedance spectroscopy. This method is composed of a feature extraction method, feature selection phase and a classification step. The feature extraction phase derives the features from the electrical impedance spectra. The extracted features consist of the impedivity at zero frequency (I0), the phase angle at 500 KHz, the high-frequency slope of phase angle, the impedance distance between spectral ends, the area under spectrum, the normalised area, the maximum of the spectrum, the distance between impedivity at I0 and the real part of the maximum frequency point and the length of the spectral curve. The system uses the information theoretic criterion as a strategy for feature selection and the combining extreme learning machines (ELMs) for the classification phase. The results of several ELMs are combined using the support vector machines classifier, and the result of classification is reported as a measure of the performance of the system. The results indicate that the proposed system achieves high accuracy in classification of breast tissues using the electrical impedance spectroscopy.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: A systematic muscle model covering regions from the fast ramp stretches in the muscle fibres to the relatively slow stretches in the human triceps surae.

  Youjiro Tamura, Akira Ito, G Andrew Cresswell
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  ABSTRACT: We have proposed a muscle model which consists of two Maxwell elements and a Voigt element in parallel. The muscle model was applied on the experiment of the force responses by the fast ramp stretch in muscle fibres to determine the mechanical parameters. In the simulation, the Maxwell element with a flexible spring and a long relaxation time seemed to correspond with the force-generating state of the cross-bridges. Next, we tried the muscle model to simulate the relatively slow movement. Experimentally, we have measured torque changes by the stretch responses in the human triceps surae. In the experiments, the derivation of torque by rotation angle showed two peaks P1 and P2. The first peak P1 originated from the elastic properties of engaged cross-bridges, while the second peak P2 was due to stretch reflex signals. The model of a single-joint system simulated well with the experimental results to show a good adaptability of the muscle model.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: Preoperative analysis of the stability of fit of a patient-specific surgical guide.

  Joyce Van den Broeck, Roel Wirix-Speetjens, Jos Vander Sloten
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  ABSTRACT: Although the use of patient-specific surgical guides has gained popularity over the past decade, little research has been done to examine in an objective and qualitative way the fit of such instruments. In this study, we have developed a model to predict the stability of a guide designed to fit on a supporting bone surface, thereby providing feedback on the translational and rotational stability of the device. The method was validated by comparing different guide designs with respect to their stability on the contact surface and comparing these results to those measured with a set of experiments. This validation experiment indicates that our stability model can be used to predict the stability of the fit of a surgical guide during the preoperative design process.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: On ballistic parameters of less lethal projectiles influencing the severity of thoracic blunt impacts.

  Julien Pavier, André Langlet, Nicolas Eches, Jean-François Jacquet
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  ABSTRACT: The development and safety certification of less lethal projectiles require an understanding of the influence of projectile parameters on projectile-chest interaction and on the resulting terminal effect. Several energy-based criteria have been developed for chest injury assessment. Many studies consider kinetic energy (KE) or energy density as the only projectile parameter influencing terminal effect. In a common KE range (100-160 J), analysis of the firing tests of two 40 mm projectiles of different masses on animal surrogates has been made in order to investigate the severity of the injuries in the thoracic region. Experimental results have shown that KE and calibre are not sufficient to discriminate between the two projectiles as regards their injury potential. Parameters, such as momentum, shape and impedance, influence the projectile-chest interaction and terminal effect. A simplified finite element model of projectile-structure interaction confirms the experimental tendencies. Within the range of ballistic parameters used, it has been demonstrated that maximum thoracic deflection is a useful parameter to predict the skeletal level of injury, and it largely depends on the projectile pre-impact momentum. However, numerical simulations show that these results are merely valid for the experimental conditions used and cannot be generalised. Nevertheless, the transmitted impulse seems to be a more general factor governing the thorax deflection.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: Behaviour of orthotropic surgical implant in hernia repair due to the material orientation and abdomen surface deformation.

  Izabela Lubowiecka
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  ABSTRACT: Surgical implants used in hernia repair reveal isotropic as well as orthotropic properties. In particular, its orthotropy, in relation to the different range of typical deformations observed in different directions and zones of abdomen surface due to the patients' life activities, has a significant influence on the extreme junction forces in the mesh-tissue connections and hence the repair persistence. The finite element model of the orthotropic implant was developed, and the junction forces in the connections of tissue and mesh were studied. The kinematical extortions representing the abdomen surface deformations identified in specific zones of hernia placement were applied to the model. The sensitive analysis was applied to specify the influence of the orthotropy (implant orientation) direction to the repair persistence. Due to the anisotropy of the human abdomen and also the different range of deformations observed in different areas of abdomen surface, the behaviour of the implant differs significantly depending on the hernia placement and the implant orientation. Especially, it is observed in the values of the implant-tissue junction forces which determinate considerably the repair persistence. The provided results and conclusions may be useful in some clinical recommendations for implantation of orthotropic surgical mesh specifying the hernia placement as well as the orthotropic implant orientation. This can also be considered in the design of new synthetic implants with more physiologic tissue-like properties also taking into account the human abdomen anisotropy.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: A diffusion tensor-based finite element model of microdialysis in the deep brain.

  Elin Diczfalusy, Mats Andersson, Karin Wårdell
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  ABSTRACT: Microdialysis of the basal ganglia was recently used to study neurotransmitter levels in relation to deep brain stimulation. In order to estimate the anatomical origin of the obtained data, the maximum tissue volume of influence (TVImax) for a microdialysis catheter was simulated using the finite element method. This study investigates the impact of brain heterogeneity and anisotropy on the TVImax using diffusion tensor imaging (DTI) to create a second-order tensor model of the basal ganglia. Descriptive statistics showed that the maximum migration distance for neurotransmitters varied by up to 55% (n = 98,444) for DTI-based simulations compared with an isotropic reference model, and the anisotropy differed between different targets in accordance with theory. The size of the TVImax was relevant in relation to the size of the anatomical structures of interest, and local tissue properties should be accounted for when relating microdialysis data to their anatomical targets.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: Development and validation of a discretised multi-body spine model in LifeMOD for biodynamic behaviour simulation.

  K T Huynh, I Gibson, B N Jagdish, W F Lu
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  ABSTRACT: This paper presents a discretised musculoskeletal multi-body spine model using the LifeMOD Biomechanics Modeller. This was obtained by refining spine segments in cervical, thoracic and lumbar regions into individual vertebra segments, using rotational joints representing the intervertebral discs, building various ligaments between vertebrae and implementing necessary lumbar muscles. To validate the model, two comparison studies were made with in vivo intradiscal pressure measurements of the L4-L5 disc as well as extension moments, axial force and shear force around L5-S1 obtained from spine models available in the literature. The results indicated that the present model is in good correlation with both cases and matches well with experimental data which found that the axial forces are in the range of 3929-4688 N and shear forces up to 650 N. This study provides a preliminary overview of our ongoing work towards building bio-fidelity discretised multi-body spine models for investigating various medical applications. These models can be useful for incorporation into design tools for wheelchairs or other seating systems which may require attention to ergonomics as well as assessing biomechanical behaviour between natural spines and spinal arthroplasty or spinal arthrodesis. Furthermore, these models can be combined with haptic-integrated graphic environments to help surgeons to examine kinematic behaviours of scoliotic spines and to propose possible surgical plans before spine correction operations.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: Surgeon variability in total knee arthroplasty component alignment: a Monte Carlo analysis.

  Christopher J Gatti, Brian R Hallstrom, Richard E Hughes
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  ABSTRACT: Component mal-alignment in total knee arthroplasty has been associated with increased revision rates and poor clinical outcomes. A significant source of variability in traditional, jig-based total knee arthroplasty is the performance of the surgeon. The purpose of this study was to determine the most sensitive steps in the femoral and tibia arthroplasty procedures. A computational model of the total knee arthroplasty procedure was created, and Monte Carlo simulations were performed that included surgeon variability in each step of the procedure. The proportion of well-aligned components from the model agrees with clinical literature in most planes. When components must be aligned within [Formula: see text] in all planes, component alignment was most sensitive to the accuracy of identifying the lateral epicondyle for the femoral component, and to the precision of the transverse plane alignment of the extramedullary guide for the tibial component. This model can be used as a tool for evaluating different procedural approaches or sources of variability to improve the quality of the total knee arthroplasty procedure.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: Stochastic multi-scale prediction on the apparent elastic moduli of trabecular bone considering uncertainties of biological apatite (BAp) crystallite orientation and image-based modelling.

  Khairul Salleh Basaruddin, Naoki Takano, Takayoshi Nakano
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  ABSTRACT: An assessment of the mechanical properties of trabecular bone is important in determining the fracture risk of human bones. Many uncertainty factors contribute to the dispersion of the estimated mechanical properties of trabecular bone. This study was undertaken in order to propose a computational scheme that will be able to predict the effective apparent elastic moduli of trabecular bone considering the uncertainties that are primarily caused by image-based modelling and trabecular stiffness orientation. The effect of image-based modelling which focused on the connectivity was also investigated. A stochastic multi-scale method using a first-order perturbation-based and asymptotic homogenisation theory was applied to formulate the stochastically apparent elastic properties of trabecular bone. The effective apparent elastic modulus was predicted with the introduction of a coefficient factor to represent the variation of bone characteristics due to inter-individual differences. The mean value of the predicted effective apparent Young's modulus in principal axis was found at approximately 460 MPa for respective 15.24% of bone volume fraction, and this is in good agreement with other experimental results. The proposed method may provide a reference for the reliable evaluation of the prediction of the apparent elastic properties of trabecular bone.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: Improving stability of locking compression plates through a design modification: a computational investigation.

  D Anitha, Shamal Das De, Khong Kok Sun, Hitendra K Doshi, Taeyong Lee
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  ABSTRACT: Femoral shaft fractures are common in both the young and elderly due to high-impact trauma and low-impact trauma, respectively. Its treatment by indirect reduction through use of locking compression plates (LCPs) has been on the rise. The LCP possess several advantages in fracture fixation, combining angular stability through use of locking screws with misalignment correction and fracture reduction onto the plate through use of conventional screws. However, there have been cases of plate breakage and fracture non-unions to warrant a study to improve its stability. A design modification is suggested for mid-diaphyseal fractures, whereby unused screw holes are removed. The structural stability of the modified and commercially available LCP is computationally analyzed using finite element modelling and a comparison made in terms of mechanical performance across different fracture lengths. A critical fracture length for which the commercially available LCP is functional as a fixator for mid-diaphyseal fractures was established. The maximum von Mises' stress attained by the commercially available LCP rose to as high as 105 MPa, whereas for the modified LCP, it did not exceed 25 MPa. As expected, these stresses were also found at screw holes, nearest to the fracture site. Critical fracture length allows clinicians to quantitatively distinguish between mid-diaphyseal fractures that can or cannot be treated by the use of LCP fixation. It is also believed that the proposed design modification will substantially increase the fatigue life of the fixator, especially at screw holes nearest to the fracture region, where most fatigue fractures are known to occur and will consequently be functional for greater fracture lengths.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: A review of numerical methods for red blood cell flow simulation.

  Meongkeun Ju, Swe Soe Ye, Bumseok Namgung, Seungkwan Cho, Hong Tong Low, Hwa Liang Leo, Sangho Kim
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  ABSTRACT: In this review, we provide an overview of the simulation techniques employed for modelling the flow of red blood cells (RBCs) in blood plasma. The scope of this review omits the fluid modelling aspect while focusing on other key components in the RBC-plasma model such as (1) describing the RBC deformation with shell-based and spring-based RBC models, (2) constitutive models for RBC aggregation based on bridging theory and depletion theory and (3) additional strategies required for completing the RBC-plasma flow model. These include topics such as modelling fluid-structure interaction with the immersed boundary method and boundary integral method, and updating the variations in multiphase fluid property through the employment of index field methods. Lastly, we summarily discuss the current state and aims of RBC modelling and suggest some research directions for the further development of this field of modelling.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: Implementation of a gait cycle loading into healthy and meniscectomised knee joint models with fibril-reinforced articular cartilage.

  Mika E Mononen, Jukka S Jurvelin, Rami K Korhonen
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  ABSTRACT: Computational models can be used to evaluate the functional properties of knee joints and possible risk locations within joints. Current models with fibril-reinforced cartilage layers do not provide information about realistic human movement during walking. This study aimed to evaluate stresses and strains within a knee joint by implementing load data from a gait cycle in healthy and meniscectomised knee joint models with fibril-reinforced cartilages. A 3D finite element model of a knee joint with cartilages and menisci was created from magnetic resonance images. The gait cycle data from varying joint rotations, translations and axial forces were taken from experimental studies and implemented into the model. Cartilage layers were modelled as a fibril-reinforced poroviscoelastic material with the menisci considered as a transversely isotropic elastic material. In the normal knee joint model, relatively high maximum principal stresses were specifically predicted to occur in the medial condyle of the knee joint during the loading response. Bilateral meniscectomy increased stresses, strains and fluid pressures in cartilage on the lateral side, especially during the first 50% of the stance phase of the gait cycle. During the entire stance phase, the superficial collagen fibrils modulated stresses of cartilage, especially in the medial tibial cartilage. The present computational model with a gait cycle and fibril-reinforced biphasic cartilage revealed time- and location-dependent differences in stresses, strains and fluid pressures occurring in cartilage during walking. The lateral meniscus was observed to have a more significant role in distributing loads across the knee joint than the medial meniscus, suggesting that meniscectomy might initiate a post-traumatic process leading to osteoarthritis at the lateral compartment of the knee joint.
  Computer Methods in Biomechanics and Biomedical Engineering 04/2013;
• Article: Effect of exercise on blood flow through the aortic valve: a combined clinical and numerical study.

  Hamidreza Ghasemi Bahraseman, Kamran Hassani, Mahdi Navidbakhsh, Daniel M Espino, Zahra Alizadeh Sani, Nasser Fatouraee
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  ABSTRACT: The aim of this study was to measure the cardiac output and stroke volume for a healthy subject by coupling an echocardiogram Doppler (echo-Doppler) method with a fluid-structure interaction (FSI) simulation at rest and during exercise. Blood flow through aortic valve was measured by Doppler flow echocardiography. Aortic valve geometry was calculated by echocardiographic imaging. An FSI simulation was performed, using an arbitrary Lagrangian-Eulerian mesh. Boundary conditions were defined by pressure loads on ventricular and aortic sides. Pressure loads applied brachial pressures with (stage 1) and without (stage 2) differences between brachial, central and left ventricular pressures. FSI results for cardiac output were 15.4% lower than Doppler results for stage 1 (r = 0.999). This difference increased to 22.3% for stage 2. FSI results for stroke volume were undervalued by 15.3% when compared to Doppler results at stage 1 and 26.2% at stage 2 (r = 0.94). The predicted mean backflow of blood was 4.6%. Our results show that numerical methods can be combined with clinical measurements to provide good estimates of patient-specific cardiac output and stroke volume at different heart rates.
  Computer Methods in Biomechanics and Biomedical Engineering 03/2013;
• Article: Microstructural residual stress in particle-filled dental composite.

  Ondřej Prejzek, Miroslav Spaniel, Tomáš Mareš
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  ABSTRACT: The main goal of this study is to develop a micromechanical model of a particle-filled dental composite focused on the residual stress (RS) field developed during the curing process in its microstructure. A finite element model of a representative volume element of filler and resin was developed, and volumetric shrinkage was simulated during the curing process. Four material models (von Mises plasticity model, Drucker-Prager plasticity model, von Mises plasticity model with stress relaxation and Drucker-Prager plasticity with stress relaxation) of the polymer resin were built to assess the influence of the material model on the resulting internal stress. The relationship between the curing process and the magnitude of the stress components will be described, and an analysis of the post-curing state of the material in particular microstructure locations will be conducted in this study. Obtained RS is comparable to the stresses developed in the material under the external load. The substantial dependence on the choice of material model for resin is to be observed, and the suitability of particular models is discussed.
  Computer Methods in Biomechanics and Biomedical Engineering 03/2013;
• Article: Integration of mechanotransduction concepts in bone tissue engineering.

  Dominique P Pioletti
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  ABSTRACT: Mechanical stimulus has been identified for a long time as a key player in the adaptation of the musculo-skeletal tissues to their function. Mechanical loading is then an intrinsic variable to be considered when new developments are proposed in bone tissue engineering. By combining structural biomechanics and mechanotransduction aspects, a new paradigm is presented for bone tissue engineering. It is proposed that in vivo mechanical loading be used to increased bone formation in the scaffold instead of pre-seeding the scaffold with cells or delivering growth factors. In this article, we demonstrated the feasibility of this approach and compared it to the classical tissue engineering strategy. In particular, we showed that bone formation could be increased in the scaffold that underwent mechanical loading during an in vivo study in rats. A model of bone formation was then proposed to translate the in vivo results into a possible clinical application where the loading of the scaffold would be transmitted by the sharing of the load between an implant and the bone scaffold.
  Computer Methods in Biomechanics and Biomedical Engineering 03/2013;
• Article: A computational study of systemic hydration in vocal fold collision.

  Pinaki Bhattacharya, Thomas Siegmund
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  ABSTRACT: Mechanical stresses develop within vocal fold (VF) soft tissues due to phonation-associated vibration and collision. These stresses in turn affect the hydration of VF tissue and thus influence voice health. In this paper, high-fidelity numerical computations are described, taking into account fully 3D geometry, realistic tissue and air properties, and high-amplitude vibration and collision. A segregated solver approach is employed, using sophisticated commercial solvers for both the VF tissue and glottal airflow domains. The tissue viscoelastic properties were derived from a biphasic formulation. Two cases were considered, whereby the tissue viscoelastic properties corresponded to two different volume fractions of the fluid phase of the VF tissue. For each case, hydrostatic stresses occurring as a result of vibration and collision were investigated. Assuming the VF tissue to be poroelastic, interstitial fluid movement within VF tissue was estimated from the hydrostatic stress gradient. Computed measures of overall VF dynamics (peak airflow velocity, magnitude of VF deformation, frequency of vibration and contact pressure) were well within the range of experimentally observed values. The VF motion leading to mechanical stresses within the VFs and their effect on the interstitial fluid flux is detailed. It is found that average deformation and vibration of VFs tend to increase the state of hydration of the VF tissue, whereas VF collision works to reduce hydration.
  Computer Methods in Biomechanics and Biomedical Engineering 03/2013;
• Article: FE study of bone quality effect on load-carrying ability of dental implants.

  V Demenko, I Linetsky, V Nesvit, L Linetska, A Shevchenko
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  ABSTRACT: Extreme stresses in surrounding bone are among the most important reasons for implant failure. Bone density (quality) is a variable that plays a decisive role in achieving predictable osseointegration and long-term survival of implants. The magnitudes of ultimate occlusal load, which generate ultimate von Mises stress at the critical point of peri-implant area for the spectrum of implants inserted into mandible with four different bone qualities (Lekholm and Zarb classification), were calculated. Geometric models of mandible segment were generated from computed tomography images and analysed with osseointegrated cylindrical implants of various dimensions. Occlusal loads were applied in their natural direction. All materials were assumed to be linearly elastic and isotropic. The investigation suggests that an implant's ultimate occlusal load indicates its load-carrying capacity. As a result, bone loss can be predicted, and viable implants can be selected by comparing the values of their ultimate occlusal load in different clinical conditions.
  Computer Methods in Biomechanics and Biomedical Engineering 03/2013;