Experimental Analysis of the Elastic Modulus of Periodontal Ligament in Nanoindentation

2016 ◽  
Author(s):  
Yu Yang ◽  
Wencheng Tang ◽  
Yao jun Wang
Keyword(s):  
Elastic Modulus ◽  
Connective Tissue ◽  
Material Properties ◽  
Experimental Analysis ◽  
Anisotropic Material ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Large Change ◽  
Experimental Results ◽  
Biomechanical Features

The periodontal ligament (PDL) is a soft connective tissue which exhibits an inhomogeneous, nonlinear, and anisotropic material properties. and the elastic modulus of different positions on each section are not the same, analysis of the material properties of PDL enables a better understanding of biomechanical features for tooth movement. The aim of this study was to study the elastic modulus of different section of PDL in nanoindentation. Experimental results indicate that the average elastic modulus elastic modulus in midroot are lower than cervical margin and apex, and there is large change in the circumferential regions.

scholarly journals Mandible Integrity and Material Properties of the Periodontal Ligament during Orthodontic Tooth Movement: A Finite-Element Study

2020 ◽  
Vol 10 (8) ◽  
pp. 2980 ◽  
Author(s):  
Heng-Li Huang ◽  
Ming-Tzu Tsai ◽  
Shih-Guang Yang ◽  
Kuo-Chih Su ◽  
Yen-Wen Shen ◽  
...  
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Material Properties ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Force Model ◽  
Orthodontic Force ◽  
Computed Tomography Images ◽  
Von Mises

We used the finite-element method (FEM) to investigate the effects of jawbone model integrity and the material properties of the periodontal ligament (PDL) on orthodontic tooth movement. Medical imaging software and computer-aided design software were used to create finite-element models of a partial and complete mandibles based on dental cone beam computed tomography images of the human skull. Additionally, we exerted an orthodontic force on the canine crown in the direction of an orthodontic miniscrew under a lower molar root to compare the von Mises strain on the canine PDL in three models: a partial mandible model under orthodontic force (Model 1), a complete mandible model under orthodontic force (Model 2), and a complete mandible model under orthodontic force with clench occlusion in the intercuspal position (ICP; Model 3). Additionally, in the complete mandible model under orthodontic force with ICP occlusion, we analyzed the effects of a PDL with a low (Model 4), moderate (Model 5), and high (Model 6) linear elastic modulus and a PDL a bilinear elastic modulus (Model 7). The simulation results for mandible integrity indicated that the maximum von Mises strains on the canine PDL for Models 1, 2, and 3 were 0.461, 0.394, and 1.811, respectively. Moreover, for the models with different PDL material properties, the maximum von Mises strains on the canine PDLs for Models 4, 5, 6, and 7 were 6.047, 2.594, 0.887, and 1.811, respectively. When the FEM was used to evaluate tooth movement caused by orthodontic force, the transformation of a complete mandible model into a partial mandible model or alteration of the elastic modulus of the PDL influenced the biomechanical responses of the PDL. Additionally, the incorporation of daily ICP occlusion resulted in a larger effect.

Relation between the ratio of elastic work to the total work of indentation and the ratio of hardness to Young's modulus for a perfect conical tip

2009 ◽  
Vol 24 (3) ◽  
pp. 590-598 ◽  
Author(s):  
J. Chen ◽  
S.J. Bull
Keyword(s):  
Numerical Simulation ◽  
Elastic Modulus ◽  
Linear Relationship ◽  
Young’S Modulus ◽  
Excellent Agreement ◽  
Material Properties ◽  
Experimental Results ◽  
Total Work ◽  
Scaling Relationship ◽  
Reduced Modulus

A linear relationship between the ratio of elastic work to the total indentation work and hardness to reduced modulus, i.e., We/Wt = λ H/Er, has been derived analytically and numerically in a number of studies and has been widely accepted. However, the scaling relationship between We/Wt and H/Er has recently been questioned, and it was found that λ is actually not a constant but is related to material properties. In this study, a new relationship between We/Wt and H/Er has been derived, which shows excellent agreement with numerical simulation and experimental results. We also propose a method for obtaining the elastic modulus and hardness of a material without invoking the commonly used Oliver and Pharr method. Furthermore, it is demonstrated that this method is less sensitive to tip imperfections than the Oliver and Pharr approach is.

Subject-Specific Finite Element Model of the Pelvis: Development, Validation and Sensitivity Studies

2005 ◽  
Vol 127 (3) ◽  
pp. 364-373 ◽  
Author(s):  
Andrew E. Anderson ◽  
Christopher L. Peters ◽  
Benjamin D. Tuttle ◽  
Jeffrey A. Weiss
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Cortical Bone ◽  
Material Properties ◽  
Experimental Results ◽  
Patient Specific ◽  
Fe Model ◽  
Bone Thickness ◽  
Subject Specific ◽  
Bone Strains

A better understanding of the three-dimensional mechanics of the pelvis, at the patient-specific level, may lead to improved treatment modalities. Although finite element (FE) models of the pelvis have been developed, validation by direct comparison with subject-specific strains has not been performed, and previous models used simplifying assumptions regarding geometry and material properties. The objectives of this study were to develop and validate a realistic FE model of the pelvis using subject-specific estimates of bone geometry, location-dependent cortical thickness and trabecular bone elastic modulus, and to assess the sensitivity of FE strain predictions to assumptions regarding cortical bone thickness as well as bone and cartilage material properties. A FE model of a cadaveric pelvis was created using subject-specific computed tomography image data. Acetabular loading was applied to the same pelvis using a prosthetic femoral stem in a fashion that could be easily duplicated in the computational model. Cortical bone strains were monitored with rosette strain gauges in ten locations on the left hemipelvis. FE strain predictions were compared directly with experimental results for validation. Overall, baseline FE predictions were strongly correlated with experimental results (r2=0.824), with a best-fit line that was not statistically different than the line y=x(experimental strains=FEpredicted strains). Changes to cortical bone thickness and elastic modulus had the largest effect on cortical bone strains. The FE model was less sensitive to changes in all other parameters. The methods developed and validated in this study will be useful for creating and analyzing patient-specific FE models to better understand the biomechanics of the pelvis.

Determination of Charge Coefficient of Piezoelectric Films Using a Combined Finite Element Model and Dynamic Loading Technique

2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Material Properties ◽  
Accurate Determination ◽  
Substrate Material ◽  
Experimental Results ◽  
Piezoelectric Composite ◽  
Piezoelectric Film ◽  
Piezoelectric Charge

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.

scholarly journals In Vitro Compression Model for Orthodontic Tooth Movement Modulates Human Periodontal Ligament Fibroblast Proliferation, Apoptosis and Cell Cycle

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 932
Author(s):  
Julia Brockhaus ◽  
Rogerio B. Craveiro ◽  
Irma Azraq ◽  
Christian Niederau ◽  
Sarah K. Schröder ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Periodontal Ligament ◽  
Environmental Changes ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Compressive Force ◽  
Periodontal Ligament Fibroblasts ◽  
Human Periodontal Ligament Fibroblasts

Human Periodontal Ligament Fibroblasts (hPDLF), as part of the periodontal apparatus, modulate inflammation, regeneration and bone remodeling. Interferences are clinically manifested as attachment loss, tooth loosening and root resorption. During orthodontic tooth movement (OTM), remodeling and adaptation of the periodontium is required in order to enable tooth movement. hPDLF involvement in the early phase-OTM compression side was investigated for a 72-h period through a well-studied in vitro model. Changes in the morphology, cell proliferation and cell death were analyzed. Specific markers of the cell cycle were investigated by RT-qPCR and Western blot. The study showed that the morphology of hPDLF changes towards more unstructured, unsorted filaments under mechanical compression. The total cell numbers were significantly reduced with a higher cell death rate over the whole observation period. hPDLF started to recover to pretreatment conditions after 48 h. Furthermore, key molecules involved in the cell cycle were significantly reduced under compressive force at the gene expression and protein levels. These findings revealed important information for a better understanding of the preservation and remodeling processes within the periodontium through Periodontal Ligament Fibroblasts during orthodontic tooth movement. OTM initially decelerates the hPDLF cell cycle and proliferation. After adapting to environmental changes, human Periodontal Ligament Fibroblasts can regain homeostasis of the periodontium, affecting its reorganization.

SLPI in Periodontal Ligament is Not Sleepy during Biophysical Force‐induced Tooth Movement

2020 ◽  
Author(s):  
Su‐Young Lee ◽  
Jung‐Sun Moon ◽  
Dong‐Wook Yang ◽  
Hong‐Il Yoo ◽  
Ji‐Yeon Jung ◽  
...  
Keyword(s):  
Periodontal Ligament ◽  
Tooth Movement

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

Biomedicines ◽  
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.

scholarly journals Application of Vibrational Spectroscopies in the Qualitative Analysis of Gingival Crevicular Fluid and Periodontal Ligament during Orthodontic Tooth Movement

2021 ◽  
Vol 10 (7) ◽  
pp. 1405
Author(s):  
Fabrizia d’Apuzzo ◽  
Ludovica Nucci ◽  
Ines Delfino ◽  
Marianna Portaccio ◽  
Giuseppe Minervini ◽  
...  
Keyword(s):  
Periodontal Ligament ◽  
Tooth Movement ◽  
Gingival Crevicular Fluid ◽  
Orthodontic Tooth Movement ◽  
High Sensitivity ◽  
Data Analysis Procedure ◽  
Vibrational Spectroscopies ◽  
Composition Structure ◽  
The Individual ◽  
Crevicular Fluid

Optical vibrational techniques show a high potentiality in many biomedical fields for their characteristics of high sensitivity in revealing detailed information on composition, structure, and molecular interaction with reduced analysis time. In the last years, we have used these techniques for investigating gingival crevicular fluid (GCF) and periodontal ligament (PDL) during orthodontic tooth treatment. The analysis with Raman and infrared signals of GCF and PDL samples highlighted that different days of orthodontic force application causes modifications in the molecular secondary structure at specific wavenumbers related to the Amide I, Amide III, CH deformation, and CH3/CH2. In the present review, we report the most relevant results and a brief description of the experimental techniques and data analysis procedure in order to evidence that the vibrational spectroscopies could be a potential useful tool for an immediate monitoring of the individual patient’s response to the orthodontic tooth movement, aiming to more personalized treatment reducing any side effects.

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