Role of subject-specific musculoskeletal loading on the prediction of bone density distribution in the proximal femur

The process of adaptive bone remodeling can be described mathematically and simulated with a self-optimizing finite element method (FEM) model. The aim of this study was to understand the effect of the basic remodeling rule on the bone density distribution of the proximal femur affected by the muscle loadings and the hip joint contact forces during normal gait (walking). The basic remodeling rule, which is an objective function for an optimization process relative to external load, was applied to predict the bone density. The purpose of the process is to obtain a constant value for the strain energy per unit bone mass, by adapting density modeling. The precise solution is dependent on the magnitude and direction of loads, loading rate, initial conditions and the parameters in the remodeling rule. In this study, we applied adaptive bone density remodeling under both static and dynamic loading conditions. In the static case, the forces at different phases in the gait cycle were statically applied as boundary conditions. The density distributions from these loadings were averaged to find the density distribution in the proximal femur. Three different initial densities were considered to investigate the effect of initial conditions. The influence of different parameters and functions on the density distribution and its convergence rate was also investigated. Furthermore, effect of changing of muscle loading and hip joint contact forces on resultant mass and density distribution of proximal femur was studied. In the dynamic approach, the forces of different phases of gait cycle were applied during different gait cycle’s times of 1.27 second (slow speed), 1.11 second (normal speed), 1.01 second (moderately fast speed), and 0.83 second (very fast speed). Although the results of bone density adaptations in both approaches were comparable with an example of an actual bone density distribution of the femoral head, neck and the proximal femoral shaft; the converged density distribution in the static approach was smoother and more realistic. It was shown that by applying more loading conditions through the gait cycle the converged density distribution is smoother. The resultant density distribution was more comparable with actual proximal femur compared to past studies.

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Determination of bone density distribution in proximal femur by using the 3D orthotropic bone adaptation model

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/09544119jeim895 ◽

2011 ◽

Vol 225 (4) ◽

pp. 365-375 ◽

Cited By ~ 6

Author(s):

M Sarikanat ◽

H Yildiz

Keyword(s):

Bone Density ◽

Density Distribution ◽

Proximal Femur ◽

Bone Adaptation ◽

Adaptation Model

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Different approaches of remodeling of bone to predict bone density distribution of proximal femur

10.17760/d10018712 ◽

2008 ◽

Author(s):

Ali Marzban

Keyword(s):

Bone Density ◽

Density Distribution ◽

Proximal Femur

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The Influence of Different Parameters of Remodeling Rule on the Resultant Density Distribution of the Proximal Femur

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-175951 ◽

2007 ◽

Author(s):

Ali Marzban ◽

Hamid Nayeb-Hashemi ◽

Paul K. Canavan

Keyword(s):

Bone Density ◽

Boundary Conditions ◽

Density Distribution ◽

Proximal Femur ◽

Gait Cycle ◽

Initial Conditions ◽

Femoral Shaft ◽

Fe Model ◽

Joint Contact Force ◽

Joint Contact

The process of adaptive bone remodeling can be described mathematically and simulated with a self-optimizing finite element (FE) model. The aim of this study was to find the bone density distribution of the proximal femur which is affected by the muscle loadings and the hip joint contact force. The basic remodeling rule, which is an objective function for an optimization process relative to external load, was applied to predict the bone density. Its purpose is to obtain a constant value for the strain energy per unit bone mass, by adapting density. The precise solution is dependent on the loads, initial conditions and the parameters in the remodeling rule. The forces at different phases of the gait cycle (walking) were applied as boundary conditions. The density distributions from these loadings were averaged to find the density distribution in the proximal femur. Three different initial densities were considered to investigate the effect of initial conditions. The influence of different parameters and functions on the density distribution and its convergence rate was also investigated. The results were comparable with an actual bone density distribution of the femoral neck head and proximal femoral shaft. It was shown that by applying more boundary conditions through the gait cycle, the converged density distribution is smoother, and more comparable with actual proximal femur.

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Subject-Specific p-FE Analysis of the Proximal Femur Utilizing Micromechanics-Based Material Properties

International Journal for Multiscale Computational Engineering ◽

10.1615/intjmultcompeng.v6.i5.70 ◽

2008 ◽

Vol 6 (5) ◽

pp. 483-498 ◽

Cited By ~ 23

Author(s):

Zohar Yosibash ◽

Nir Trabelsi ◽

Christian Hellmich

Keyword(s):

Proximal Femur ◽

Material Properties ◽

Fe Analysis ◽

Subject Specific

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The role of inhibition of osteocyte apoptosis in mediating orthodontic tooth movement and periodontal remodeling: a pilot study

Progress in Orthodontics ◽

10.1186/s40510-021-00366-4 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Michele Kaplan ◽

Zana Kalajzic ◽

Thomas Choi ◽

Imad Maleeh ◽

Christopher L. Ricupero ◽

...

Keyword(s):

Bone Density ◽

Alveolar Bone ◽

Tooth Movement ◽

Orthodontic Tooth Movement ◽

Tartrate Resistant Acid Phosphatase ◽

Osteocyte Apoptosis ◽

Saline Administration ◽

Group 2 ◽

Group 1

Abstract Background Orthodontic tooth movement (OTM) has been shown to induce osteocyte apoptosis in alveolar bone shortly after force application. However, how osteocyte apoptosis affects orthodontic tooth movement is unknown. The goal of this study was to assess the effect of inhibition of osteocyte apoptosis on osteoclastogenesis, changes in the alveolar bone density, and the magnitude of OTM using a bisphosphonate analog (IG9402), a drug that affects osteocyte and osteoblast apoptosis but does not affect osteoclasts. Material and methods Two sets of experiments were performed. Experiment 1 was used to specifically evaluate the effect of IG9402 on osteocyte apoptosis in the alveolar bone during 24 h of OTM. For this experiment, twelve mice were divided into two groups: group 1, saline administration + OTM24-h (n=6), and group 2, IG9402 administration + OTM24-h (n=6). The contralateral unloaded sides served as the control. The goal of experiment 2 was to evaluate the role of osteocyte apoptosis on OTM magnitude and osteoclastogenesis 10 days after OTM. Twenty mice were divided into 4 groups: group 1, saline administration without OTM (n=5); group 2, IG9402 administration without OTM (n=5); group 3, saline + OTM10-day (n=6); and group 4, IG9402 + OTM10-day (n=4). For both experiments, tooth movement was achieved using Ultra Light (25g) Sentalloy Closed Coil Springs attached between the first maxillary molar and the central incisor. Linear measurements of tooth movement and alveolar bone density (BVF) were assessed by MicroCT analysis. Cell death (or apoptosis) was assessed by terminal dUTP nick-end labeling (TUNEL) assay, while osteoclast and macrophage formation were assessed by tartrate-resistant acid phosphatase (TRAP) staining and F4/80+ immunostaining. Results We found that IG9402 significantly blocked osteocyte apoptosis in alveolar bone (AB) at 24 h of OTM. At 10 days, IG9402 prevented OTM-induced loss of alveolar bone density and changed the morphology and quality of osteoclasts and macrophages, but did not significantly affect the amount of tooth movement. Conclusion Our study demonstrates that osteocyte apoptosis may play a significant role in osteoclast and macrophage formation during OTM, but does not seem to play a role in the magnitude of orthodontic tooth movement.

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AT1 and AT2 Receptor Knockout Changed Osteonectin and Bone Density in Mice in Periodontal Inflammation Experimental Model

International Journal of Molecular Sciences ◽

10.3390/ijms22105217 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5217

Author(s):

Maria Laura de Souza Lima ◽

Caroline Addison Carvalho Xavier de Medeiros ◽

Gerlane Coelho Bernardo Guerra ◽

Robson Santos ◽

Michael Bader ◽

...

Keyword(s):

Bone Density ◽

Bone Loss ◽

Experimental Model ◽

At2 Receptor ◽

Micro Ct ◽

Rt Pcr ◽

Osteoblast Cells ◽

Periodontal Inflammation ◽

Bone Trabeculae

Background: The aim of this study was to evaluate the role of AT1 and AT2 receptors in a periodontal inflammation experimental model. Methods: Periodontal inflammation was induced by LPS/Porphyromonas gingivalis. Maxillae, femur, and vertebra were scanned using Micro-CT. Maxillae were analyzed histopathologically, immunohistochemically, and by RT-PCR. Results: The vertebra showed decreased BMD in AT1 H compared with WT H (p < 0.05). The femur showed increased Tb.Sp for AT1 H and AT2 H, p < 0.01 and p < 0.05, respectively. The Tb.N was decreased in the vertebra (WT H-AT1 H: p < 0.05; WT H-AT2 H: p < 0.05) and in the femur (WT H-AT1 H: p < 0.01; WT H-AT2 H: p < 0.05). AT1 PD increased linear bone loss (p < 0.05) and decreased osteoblast cells (p < 0.05). RANKL immunostaining was intense for AT1 PD and WT PD (p < 0.001). OPG was intense in the WT H, WT PD, and AT2 PD when compared to AT1 PD (p < 0.001). AT1 PD showed weak immunostaining for osteocalcin compared with WT H, WT PD, and AT2 PD (p < 0.001). AT1 H showed significantly stronger immunostaining for osteonectin in fibroblasts compared to AT2 H (p < 0.01). Conclusion: AT1 receptor knockout changed bone density, the quality and number of bone trabeculae, decreased the number of osteoblast cells, and increased osteonectin in fibroblasts.

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Myeloid HIF1α Is Involved in the Extent of Orthodontically Induced Tooth Movement

Biomedicines ◽

10.3390/biomedicines9070796 ◽

2021 ◽

Vol 9 (7) ◽

pp. 796

Author(s):

Christian Kirschneck ◽

Nadine Straßmair ◽

Fabian Cieplik ◽

Eva Paddenberg ◽

Jonathan Jantsch ◽

...

Keyword(s):

Bone Density ◽

Periodontal Ligament ◽

Tooth Movement ◽

Hypoxia Inducible Factor ◽

Myeloid Cells ◽

Orthodontic Tooth Movement ◽

Periodontal Ligament Fibroblasts ◽

Expression Of Genes ◽

Periodontal Bone Loss

During orthodontic tooth movement, transcription factor hypoxia-inducible factor 1α (HIF1α) is stabilised in the periodontal ligament. While HIF1α in periodontal ligament fibroblasts can be stabilised by mechanical compression, in macrophages pressure application alone is not sufficient to stabilise HIF1α. The present study was conducted to investigate the role of myeloid HIF1α during orthodontic tooth movement. Orthodontic tooth movement was performed in wildtype and Hif1αΔmyel mice lacking HIF1α expression in myeloid cells. Subsequently, µCT images were obtained to determine periodontal bone loss, extent of orthodontic tooth movement and bone density. RNA was isolated from the periodontal ligament of the control side and the orthodontically treated side, and the expression of genes involved in bone remodelling was investigated. The extent of tooth movement was increased in Hif1αΔmyel mice. This may be due to the lower bone density of the Hif1αΔmyel mice. Deletion of myeloid Hif1α was associated with increased expression of Ctsk and Acp5, while both Rankl and its decoy receptor Opg were increased. HIF1α from myeloid cells thus appears to play a regulatory role in orthodontic tooth movement.

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