Numerical Simulation of Mandible Bone Remodeling under Tooth Loading: A Parametric Study

Abstract Bone adapts to the change of mechanical stimulus by bone remodeling activities. A number of numerical algorithms have been developed to model the adaptive bone remodeling under mechanical loads for orthopedic and dental applications. This paper examines the effects of several model parameters on the computed apparent bone density in mandible under normal chewing and biting forces. The density change rate was based on the strain energy density per unit mass. The algorithms used in this study containing an equilibrium zone (lazy zone) and saturated values of density change rate provides certain stability to result in convergence without discontinuous checkerboard patterns. The parametric study shows that when different boundary conditions were applied, the bone density distributions at convergence were very different, except in the vicinity of the applied loads. Compared with the effects of boundary conditions, the models are less sensitive to the choice of initial density values. Several models starting from different initial density values resulted in similar but not exactly the same bone density distribution at convergence. The results also show that higher reference value of mechanical stimulus resulted in lower average bone density at convergence. Moreover, the width of equilibrium zone did not substantially affect the average density at convergence. However, with increasing width, the areas with the highest and the lowest bone density areas were all reduced. The limitations of the models and challenges for future work were discussed for the better agreement between the computed results and the in vivo data.

Download Full-text

Parametric study of control mechanism of cortical bone remodeling under mechanical stimulus

Acta Mechanica Sinica ◽

10.1007/s10409-009-0313-z ◽

2009 ◽

Vol 26 (1) ◽

pp. 37-44 ◽

Cited By ~ 4

Author(s):

Yanan Wang ◽

Qing-Hua Qin

Keyword(s):

Cortical Bone ◽

Bone Remodeling ◽

Parametric Study ◽

Control Mechanism ◽

Mechanical Stimulus ◽

Cortical Bone Remodeling

Download Full-text

Activity and Loading Influence the Predicted Bone Remodeling Around Cemented Hip Replacements

Journal of Biomechanical Engineering ◽

10.1115/1.4026256 ◽

2014 ◽

Vol 136 (4) ◽

Cited By ~ 4

Author(s):

Alexander S. Dickinson

Keyword(s):

Bone Density ◽

Bone Remodeling ◽

Density Change ◽

Stem Density ◽

X Rays ◽

Joint Loading ◽

Periprosthetic Bone ◽

Joint Force ◽

Postoperative Changes ◽

Prediction Approach

Periprosthetic bone remodeling is frequently observed after total hip replacement. Reduced bone density increases the implant and bone fracture risk, and a gross loss of bone density challenges fixation in subsequent revision surgery. Computational approaches allow bone remodeling to be predicted in agreement with the general clinical observations of proximal resorption and distal hypertrophy. However, these models do not reproduce other clinically observed bone density trends, including faster stabilizing mid-stem density losses, and loss-recovery trends around the distal stem. These may resemble trends in postoperative joint loading and activity, during recovery and rehabilitation, but the established remodeling prediction approach is often used with identical pre- and postoperative load and activity assumptions. Therefore, this study aimed to evaluate the influence of pre- to postoperative changes in activity and loading upon the predicted progression of remodeling. A strain-adaptive finite element model of a femur implanted with a cemented Charnley stem was generated, to predict 60 months of periprosthetic remodeling. A control set of model input data assumed identical pre- and postoperative loading and activity, and was compared to the results obtained from another set of inputs with three varying activity and load profiles. These represented activity changes during rehabilitation for weak, intermediate and strong recoveries, and pre- to postoperative joint force changes due to hip center translation and the use of walking aids. Predicted temporal bone density change trends were analyzed, and absolute bone density changes and the time to homeostasis were inspected, alongside virtual X-rays. The predicted periprosthetic bone density changes obtained using modified loading inputs demonstrated closer agreement with clinical measurements than the control. The modified inputs also predicted the clinically observed temporal density change trends, but still under-estimated density loss during the first three postoperative months. This suggests that other mechanobiological factors have an influence, including the repair of surgical micro-fractures, thermal damage and vascular interruption. This study demonstrates the importance of accounting for pre- to postoperative changes in joint loading and patient activity when predicting periprosthetic bone remodeling. The study's main weakness is the use of an individual patient model; computational expense is a limitation of all previously reported iterative remodeling analysis studies. However, this model showed sufficient computational efficiency for application in probabilistic analysis, and is an easily implemented modification of a well-established technique.

Download Full-text

Mechanobiological Behavior of a Pathological Bone

10.5772/intechopen.97029 ◽

2021 ◽

Author(s):

Imane Ait Oumghar ◽

Abdelwahed Barkaoui ◽

Patrick Chabrand

Keyword(s):

Bone Density ◽

Mathematical Models ◽

Bone Remodeling ◽

Tissue Regeneration ◽

Bone Healing ◽

Bone Cells ◽

Bone Microarchitecture ◽

Mechanical Stimulus ◽

Bone Diseases ◽

Skeletal Tissue

Bone density and bone microarchitecture are two principle parameters needed for the evaluation of mechanical bone performance and consequently the detection of bone diseases. The mechanobiological behavior of the skeletal tissue has been described through several mathematical models. Generally, these models fingerboard different length scale processes, such as the mechanical, the biological, and the chemical ones. By means of the mechanical stimulus and the biological factors involved in tissue regeneration, bone cells’ behavior and bone volume changes are determined. The emergence of bone diseases leads to disrupt the bone remodeling process and thus, induces bone mechanical properties’ alteration. In the present chapter, an overview of bone diseases and their relationship with bone density alteration will be presented. Besides, several studies treating bone diseases’ effect on bone remodeling will be discussed. Finally, the mechanobiological models proposed to treat bone healing and drugs’ effect on bone, are going to be reviewed. For this sake, the chapter is subdivided into three main sequences: (i) Bone remodeling, (ii) Bone deterioration causes, (iii) Mathematical models of a pathological bone, and (iv) Mechanobiological models treating bone healing and drugs effect.

Download Full-text

Faculty Opinions recommendation of Rate of bone density change does not enhance fracture prediction in routine clinical practice.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.14092956.15565056 ◽

2012 ◽

Author(s):

Clifford Rosen

Keyword(s):

Clinical Practice ◽

Bone Density ◽

Routine Clinical Practice ◽

Fracture Prediction ◽

Density Change

Download Full-text

Model of vortex flow of charge in a vessel with turbine impeller

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19871888 ◽

1987 ◽

Vol 52 (8) ◽

pp. 1888-1904

Author(s):

Miloslav Hošťálek ◽

Ivan Fořt

Keyword(s):

Boundary Conditions ◽

Equations Of Motion ◽

Theoretical Data ◽

Eddy Diffusion ◽

Quantitative Agreement ◽

Creeping Flow ◽

Model Parameters ◽

Mean Flow ◽

Two Dimensional Flow ◽

Vorticity Transport

A theoretical model is described of the mean two-dimensional flow of homogeneous charge in a flat-bottomed cylindrical tank with radial baffles and six-blade turbine disc impeller. The model starts from the concept of vorticity transport in the bulk of vortex liquid flow through the mechanism of eddy diffusion characterized by a constant value of turbulent (eddy) viscosity. The result of solution of the equation which is analogous to the Stokes simplification of equations of motion for creeping flow is the description of field of the stream function and of the axial and radial velocity components of mean flow in the whole charge. The results of modelling are compared with the experimental and theoretical data published by different authors, a good qualitative and quantitative agreement being stated. Advantage of the model proposed is a very simple schematization of the system volume necessary to introduce the boundary conditions (only the parts above the impeller plane of symmetry and below it are distinguished), the explicit character of the model with respect to the model parameters (model lucidity, low demands on the capacity of computer), and, in the end, the possibility to modify the given model by changing boundary conditions even for another agitating set-up with radially-axial character of flow.

Download Full-text

On the effect of antiresorptive drugs on the bone remodeling of the mandible after dental implantation: a mathematical model

Scientific Reports ◽

10.1038/s41598-021-82502-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mehran Ashrafi ◽

Farzan Ghalichi ◽

Behnam Mirzakouchaki ◽

Manuel Doblare

Keyword(s):

Mathematical Model ◽

Bone Density ◽

Bone Remodeling ◽

Dental Implants ◽

Implant Design ◽

Patient Specific ◽

Dental Implantation ◽

Antiresorptive Agents ◽

Antiresorptive Drugs

AbstractBone remodeling identifies the process of permanent bone change with new bone formation and old bone resorption. Understanding this process is essential in many applications, such as optimizing the treatment of diseases like osteoporosis, maintaining bone density in long-term periods of disuse, or assessing the long-term evolution of the bone surrounding prostheses after implantation. A particular case of study is the bone remodeling process after dental implantation. Despite the overall success of this type of implants, the increasing life expectancy in developed countries has boosted the demand for dental implants in patients with osteoporosis. Although several studies demonstrate a high success rate of dental implants in osteoporotic patients, it is also known that the healing time and the failure rate increase, necessitating the adoption of pharmacological measures to improve bone quality in those patients. However, the general efficacy of these antiresorptive drugs for osteoporotic patients is still controversial, requiring more experimental and clinical studies. In this work, we investigate the effect of different doses of several drugs, used nowadays in osteoporotic patients, on the evolution of bone density after dental implantation. With this aim, we use a pharmacokinetic–pharmacodynamic (PK/PD) mathematical model that includes the effect of antiresorptive drugs on the RANK/RANK-L/OPG pathway, as well as the mechano-chemical coupling with external mechanical loads. This mechano-PK/PD model is then used to analyze the evolution of bone in normal and osteoporotic mandibles after dental implantation with different drug dosages. We show that using antiresorptive agents such as bisphosphonates or denosumab increases bone density and the associated mechanical properties, but at the same time, it also increases bone brittleness. We conclude that, despite the many limitations of these very complex models, the one presented here is capable of predicting qualitatively the evolution of some of the main biological and chemical variables associated with the process of bone remodeling in patients receiving drugs for osteoporosis, so it could be used to optimize dental implant design and coating for osteoporotic patients, as well as the drug dosage protocol for patient-specific treatments.

Download Full-text

INFLUENCE OF THE PYROLYTIC COMPACTION PROCESS ON THE PHYSICAL AND MECHANICAL PROPERTIES OF HIGH-DENSITY CARBON-CARBON COMPOSITE MATERIALS BASED ON PITCH MATRICES

Spravochnik Inzhenernyi zhurnal ◽

10.14489/hb.2021.10.pp.003-009 ◽

2021 ◽

pp. 3-9

Author(s):

V. V. Kulakov ◽

M. I. Pankov ◽

V. A. Sivurova ◽

M. S. Luchkin ◽

A. K. Golubkov ◽

...

Keyword(s):

Carbon Fibers ◽

Initial Density ◽

Physical And Mechanical Properties ◽

Pyrolytic Carbon ◽

Carbon Composite ◽

Test Results ◽

High Modulus ◽

Compaction Process ◽

Carbon Composite Materials ◽

Density Values

The efficiency of the pyrolytic carbon compaction process by decomposing methane in samples of a carbon-carbon composite randomly reinforced with discrete high-modulus (graphitized) carbon fibers with different densities is investigated. The analysis of the test results of samples for determining the compressive strength, determining the densities of samples after compaction with pyrocarbon and after compaction by impregnation and carbonization under pressure is carried out. Scanning electron microscopy (SEM) was used to study the structure of material samples with different initial density values.

Download Full-text

Updating Substructure Models With Dynamic Boundary Conditions

Volume 3C: 15th Biennial Conference on Mechanical Vibration and Noise — Vibration Control, Analysis, and Identification ◽

10.1115/detc1995-0701 ◽

1995 ◽

Author(s):

Michael Link ◽

Zheng Qian

Keyword(s):

Boundary Conditions ◽

Dynamic Stiffness ◽

Design Parameters ◽

Physical Parameters ◽

Model Parameters ◽

Dynamic Boundary Conditions ◽

Main Structure ◽

Modal Data ◽

Residual Structure ◽

Dynamic Boundary

Abstract In recent years procedures for updating analytical model parameters have been developed by minimizing differences between analytical and preferably experimental modal analysis results. Provided that the initial analysis model contains parameters capable of describing possible damage these techniques could also be used for damage detection. In this case the parameters are updated using test data before and after the damage. Looking at complex structures with hundreds of parameters one generally has to measure the modal data at many locations and try to reduce the number of unknown parameters by some kind of localization technique because the measurement information is generally not sufficient to identify all the parameters equally distributed all over the structure. Another way of reducing the number of parameters shall be presented here. This method is based on the idea of measuring only a part of the structure and replacing the residual structure by dynamic boundary conditions which describe the dynamic stiffness at the interfaces between the measured main structure and the remaining unmeasured residual structure. This approach has some advantage since testing could be concentrated on critical areas where structural modifications are expected either due to damage or due to intended design changes. The dynamic boundary conditions are expressed in Craig-Bampton (CB) format by transforming the mass and stiffness matrices of the unmeasured residual structure to the interface degrees of freedom (DOF) and to the modal DOFs of the residual structure fixed at the interface. The dynamic boundary stiffness concentrates all physical parameters of the residual structure in only a few parameters which are open for updating. In this approach damage or modelling errors within the unmeasured residual structure are taken into account only in a global sense whereas the measured main structure is parametrized locally as usual by factoring mass and stiffness submatrices defining the type and the location of the physical parameters to be identified. The procedure was applied to identify the design parameters of a beam type frame structure with bolted joints using experimental modal data.

Download Full-text

Analytical Buckling Loads of Columns Weakened Simultaneously with Transverse Cracks and Partial Delamination

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455419500275 ◽

2019 ◽

Vol 19 (03) ◽

pp. 1950027 ◽

Cited By ~ 1

Author(s):

Igor Planinc ◽

Simon Schnabl

Keyword(s):

Mathematical Model ◽

Analytical Solution ◽

Boundary Conditions ◽

Parametric Study ◽

Transverse Crack ◽

Transverse Cracks ◽

Buckling Loads ◽

Crack Location ◽

Benchmark Solution ◽

First Time

This paper focuses on development of a new mathematical model and its analytical solution for buckling analysis of elastic columns weakened simultaneously with transverse open cracks and partial longitudinal delamination. Consequently, the analytical solution for buckling loads is derived for the first time. The critical buckling loads are calculated using the proposed analytical model. A parametric study is performed to investigate the effects of transverse crack location and magnitude, length and degree of partial longitudinal delamination, and different boundary conditions on critical buckling loads of weakened columns. It is shown that the critical buckling loads of weakened columns can be greatly affected by all the analyzed parameters. Finally, the presented results can be used as a benchmark solution.

Download Full-text