scholarly journals PROPERTIES OF THE HAND MIXED PMMA BASED CEMENT FOR BIOMEDICAL APPLICATIONS

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Fatima Živić ◽  
Nenad Grujović ◽  
Svetlana Pelemiš ◽  
Dragan Adamović
Keyword(s):  
Mechanical Behavior ◽  
Bone Cement ◽  
Mechanical Response ◽  
Normal Load ◽  
Sample Surface ◽  
Maximum Load ◽  
Material Structure ◽  
Hardened Cement ◽  
Pmma Bone Cement ◽  
Pmma Beads

This paper presents insights into the recent trends in development of PMMA bone cements considering their improvements for applications in clinical practice. Experimental investigation of hand mixed PMMA bone cement was realized, aiming to determine mechanical behavior of the material during nanoindentation. Standard multi-cycle indentation tests were applied, with maximum load of 15 N and immediate load relaxation down to 5 N, with sharp Vickers indenter. Indentation curves were obtained and analyzed as the function of the normal load vs penetration depth, for three different numbers of cycles (100, 200 and 300 cycles) and different indentation positions on the sample surface. Resulting indents were analyses from the aspect of the final material structure and its subsequent mechanical behavior. Agglomeration of PMMA beads was observed in the final hardened cement in some surface zones, thus indicating non-homogenous material structure. Changes in the number of cycles did not show significant influence on the mechanical response of the sample. However, sites with agglomerated PMMA beads showed significantly different indentation curves, thus indicating that hand-mixing of PMMA bone cement can produce non-homogenous final material structure.

An Investigation into the Fracture Mechanical Behavior of Bone Cement: Simulation Using Cohesive Zone Models (CZMs)

2010 ◽  
Vol 156-157 ◽  
pp. 1658-1664
Author(s):  
Xiao Hui Huang ◽  
Wen Guang Liu ◽  
Guo Qun Zhao ◽  
Xin Hai Zhao
Keyword(s):  
Mechanical Behavior ◽  
Bone Cement ◽  
Fracture Mechanism ◽  
Cohesive Zone ◽  
Maximum Load ◽  
Distinct Advantage ◽  
Continuum Structure ◽  
Safe Working ◽  
Cohesive Zones ◽  
The Continuum

In this investigation, we propose a new concept to embed cohesive zone into the continuum structure of bone cement, an example of brittle material, in investigating the mechanical behavior and fracture mechanism and to predict the fracture which elastic fracture mechanics (EFM) is unable to. Four finite element (FE) models with embedded cohesive zones for the simulations of tensile, compression, double shear and 3-point bending tests have been implemented. Cohesive zones (CZ) are embedded at high risks of fracture with orientations determined by fracture mode. A bilinear cohesive traction-separation law (TSL) is applied. The fracture parameters in traction-separation curve are validated and justified in the simulations to agree well with the force-displacement curves in the four practical tests. Apart from the maximum load, the perpetual safe working load (SWL) in theory also can be predicted by tracing the history of the stiffness degradation of fractured cohesive zone by means of simulation. A distinct advantage of our numerical model is that it is able to extend to investigate the mechanical behavior and fracture mechanism of other brittle materials. The proposed method with embedded cohesive zones in FE models can be introduced to predict the fracture and to forecast the maximum load and safe working load (SWL) of the continuum structure in more complicated loading conditions.

Bioactive PMMA-Based Cement Incorporated with Nano-Sized Rutile Particles

2006 ◽  
Vol 309-311 ◽  
pp. 797-800 ◽  
Author(s):  
Masami Hashimoto ◽  
Hiroaki Takadama ◽  
Mineo Mizuno ◽  
Tadashi Kokubo ◽  
Koji Goto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Simulated Body Fluid ◽  
Mechanical Strength ◽  
Bone Cement ◽  
Body Fluid ◽  
Bone Substitutes ◽  
Hardened Cement ◽  
Pmma Bone Cement

Bioactive bone cement with mechanical properties higher than that of commercial polymethylmethacrylate (PMMA) bone cement are strongly desired to be developed. In the present study, PMMA-based cement incorporated with nano-sized rutile particles was prepared. The PMMA-based cement (rutile content was 50 wt%) shows the compressive strength (136 MPa) higher than that of commercial PMMA bone cement (88 MPa). The hardened cement formed apatite on the surface in a simulated body fluid within 3 days. Therefore, this PMMA-based cement incorporated with rutile particles might be useful as cement for fixation of prostheses as well as self-setting bone substitutes, because of its high apatite forming ability and mechanical strength.

Bioactive Additives and Functional Monomers Affect on PMMA Bone Cement: Mechanical and Biocompatibility Properties

2011 ◽  
Author(s):  
Morshed Khandaker ◽  
Yanling Li ◽  
Ping Liu ◽  
Melville B. Vaughan
Keyword(s):  
Fracture Toughness ◽  
Cell Adhesion ◽  
Flexural Strength ◽  
Methyl Methacrylate ◽  
Bone Cement ◽  
Composite Specimen ◽  
Poly Methyl Methacrylate ◽  
Pmma Bone Cement ◽  
Significant Difference ◽  
Pmma Beads

The most common bone cement material used clinically today for orthopedic surgeries is poly methyl methacrylate (PMMA). In general, poly Methyl MethAcrylate (PMMA) beads are added to MMA monomer with bead and monomer ratio of 2:1 to prepare the PMMA bone cement. Conventional PMMA bone cement has several mechanical and biological disadvantages. To overcome these disadvantages, researchers investigated several bioactive additives to PMMA bone cement, such as MgO, hydroxyapatite (HAp), chitosan (CS). Additionally, functional monomer, such as glycidyl methacrylate (GMA) was used in addition or substitution to MMA to enhance the properties of PMMA bone cement. A comparative study is required to evaluate the effect that different bioadditives and monomers have on the mechanical and biological performances on PMMA bone cement. The goal of this study is to determine the most suitable additives and alternative monomer for PMMA bone cement that can enhance the mechanical and biological performances of PMMA bone cement. Cobalt™ HV bone cement (referred as CBC), a commercial orthopedic bone cement, was used in this study as PMMA bone cement. MgO, hydroxyapatite (HAp), chitin (CT), chitosan (CS), Barium sulfate (BaSO4) and Silica (SiO2) were mixed with PMMA beads to prepare CBC-MgO, CBC-HAp, CBC-CT, CBC-CS, CBC-BaSO4 and CBC-SiO2 specimens. Additives included CBC were referred as composite specimen. CBC and composite specimens were further grouped according to the application of GMA as replacement of MMA monomer. Two groups of CBC and composite specimen were prepared. In the first group, CBC and composite specimens were prepared using MMA monomer only, referred as without GMA specimen. In the second group, CBC and composite specimens were prepared using GMA and MMA monomers, referred as with GMA specimen. There are three general research questions: (1) Is there a significant difference in the mechanical and biological performances between CBC (control) and different composite specimens that contain GMA? (2) Is there a significant difference in the in the mechanical and biological performances between CBC (control) and different composite specimens that do not contain GMA? and (3) Is there a significant difference in the mechanical and biological performances between specimens mixed with and without GMA? Elastic and fracture properties of different CBC and composite cements were calculated from three point bend experiments. Osteoblast cell adhesion experiments were performed on different CBC and composite cement on a custom made well plate. This study found that flexural strength and fracture toughness of the CBC specimens that contain GMA is significantly greater than the flexural strengths of all other specimens that contain GMA. In contrast, flexural strength and fracture toughness of the CBC-SiO2 specimens that do not contain GMA is significantly greater than the flexural strengths of all other specimens that contain GMA. This study also found that cell adhesion on the MgO impregnated CBC specimens is significantly greater than the cell adhesion of all other specimens for samples that contain GMA or do not contain GMA.

scholarly journals Influence of HRGO Nanoplatelets on Behaviour and Processing of PMMA Bone Cement for Surgery

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2027
Author(s):  
Jaime Orellana ◽  
Ynés Yohana Pastor ◽  
Fernando Calle ◽  
José Ygnacio Pastor
Keyword(s):  
Graphene Oxide ◽  
Methyl Methacrylate ◽  
Bone Cement ◽  
Reduced Graphene Oxide ◽  
Sintering Temperature ◽  
Structural Function ◽  
Mechanical And Thermal Properties ◽  
Poly Methyl Methacrylate ◽  
Pmma Bone Cement ◽  
Reduced Graphene

Bone cement, frequently based on poly (methyl methacrylate), is commonly used in different arthroplasty surgical procedures and its use is essential for prosthesis fixation. However, its manufacturing process reaches high temperatures (up to 120 °C), producing necrosis in the patients' surrounding tissues. To help avoid this problem, the addition of graphene could delay the polymerisation of the methyl methacrylate as it could, simultaneously, favour the optimisation of the composite material's properties. In this work, we address the effect of different percentages of highly reduced graphene oxide with different wt.% (0.10, 0.50, and 1.00) and surface densities (150, 300, 500, and 750 m2/g) on the physical, mechanical, and thermal properties of commercial poly (methyl methacrylate)-based bone cement and its processing. It was noted that a lower sintering temperature was achieved with this addition, making it less harmful to use in surgery and reducing its adverse effects. In contrast, the variation of the density of the materials did not introduce significant changes, which indicates that the addition of highly reduced graphene oxide would not significantly increase bone porosity. Lastly, the mechanical properties (strength, elastic modulus, and fracture toughness) were reduced by almost 20%. Nevertheless, their typical values are high enough that these new materials could still fulfil their structural function. In conclusion, this paper presents a way to control the sintering temperature, without significant degradation of the mechanical performance, by adding highly reduced graphene oxide so that local necrosis of bone cement based on poly (methyl methacrylate) used in surgery is avoided.

scholarly journals Developing of PMMA Bone Cement Performance by Modified TiO2NPs

2021 ◽  
Vol 1094 (1) ◽  
pp. 012150
Author(s):  
S K Al-Janabi ◽  
M H Al-Maamori ◽  
A J Braihi
Keyword(s):  
Bone Cement ◽  
Pmma Bone Cement

Dependence of Mechanical Behavior of the Murine Tail Disc on Regional Material Properties: A Parametric Finite Element Study

2005 ◽  
Vol 127 (7) ◽  
pp. 1158-1167 ◽  
Author(s):  
Adam H. Hsieh ◽  
Diane R. Wagner ◽  
Louis Y. Cheng ◽  
Jeffrey C. Lotz
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Nucleus Pulposus ◽  
Material Properties ◽  
Mechanical Response ◽  
Swelling Pressure ◽  
Transient Behavior ◽  
Sensitivity Analyses ◽  
Intact Mouse

In vivo rodent tail models are becoming more widely used for exploring the role of mechanical loading on the initiation and progression of intervertebral disc degeneration. Historically, finite element models (FEMs) have been useful for predicting disc mechanics in humans. However, differences in geometry and tissue properties may limit the predictive utility of these models for rodent discs. Clearly, models that are specific for rodent tail discs and accurately simulate the disc’s transient mechanical behavior would serve as important tools for clarifying disc mechanics in these animal models. An FEM was developed based on the structure, geometry, and scale of the mouse tail disc. Importantly, two sources of time-dependent mechanical behavior were incorporated: viscoelasticity of the matrix, and fluid permeation. In addition, a novel strain-dependent swelling pressure was implemented through the introduction of a dilatational stress in nuclear elements. The model was then validated against data from quasi-static tension-compression and compressive creep experiments performed previously using mouse tail discs. Finally, sensitivity analyses were performed in which material parameters of each disc subregion were individually varied. During disc compression, matrix consolidation was observed to occur preferentially at the periphery of the nucleus pulposus. Sensitivity analyses revealed that disc mechanics was greatly influenced by changes in nucleus pulposus material properties, but rather insensitive to variations in any of the endplate properties. Moreover, three key features of the model—nuclear swelling pressure, lamellar collagen viscoelasticity, and interstitial fluid permeation—were found to be critical for accurate simulation of disc mechanics. In particular, collagen viscoelasticity dominated the transient behavior of the disc during the initial 2200s of creep loading, while fluid permeation governed disc deformation thereafter. The FEM developed in this study exhibited excellent agreement with transient creep behavior of intact mouse tail motion segments. Notably, the model was able to produce spatial variations in nucleus pulposus matrix consolidation that are consistent with previous observations in nuclear cell morphology made in mouse discs using confocal microscopy. Results of this study emphasize the need for including nucleus swelling pressure, collagen viscoelasticity, and fluid permeation when simulating transient changes in matrix and fluid stress/strain. Sensitivity analyses suggest that further characterization of nucleus pulposus material properties should be pursued, due to its significance in steady-state and transient disc mechanical response.

Development of Novel Bioactive PMMA-Based Bone Cement and its In Vitro and In Vivo Evaluation

2006 ◽  
Vol 309-311 ◽  
pp. 801-804 ◽  
Author(s):  
S.B. Cho ◽  
Akari Takeuchi ◽  
Ill Yong Kim ◽  
Sang Bae Kim ◽  
Chikara Ohtsuki ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Bone Cement ◽  
The Novel ◽  
In Vivo Evaluation ◽  
Natural Bone ◽  
Pmma Bone Cement ◽  
Rabbit Tibia

In order to overcome the disadvantage of commercialized PMMA bone cement, we have developed novel PMMA-based bone cement(7P3S) reinforced by 30 wt.% of bioactive CaO-SiO2 gel powders to induce the bioactivity as well as to increase mechanical property for the PMMA bone cement. The novel 7P3S bone cement hardened after mixing for about 7 minutes. For in vitro evaluation, apatite forming ability of it was investigated using SBF. When the novel 7P3S bone cement was soaked into SBF, it formed apatite on its surfaces within 1 week Furthermore; there is no decrease in its compressive strength within 9 weeks soaking in SBF. It is though that hardly decrease in compressive strength of 7P3S bone cement in SBF is due to the relative small amount of gel powder or its spherical shape and monosize. In vivo evaluation of the novel 7P3S bone cement was carried out using rabbit. After implantion into rabbit tibia for several periods, the interface between novel bone cement and natural bone was evaluated by CT images. According to the results, the novel bone cement directly contact to the natural bone without fibrous tissue after implantation for 4 weeks. This results indicates that the newly developed 7P3S bone cement can bond to the living bone and also be effectively used as bioactive bone cement without decrease in mechanical property.

A Proof of Concept Study of the Mechanical Behavior of Lattice Structures Used to Design a Shoulder Hemi-Prosthesis

2021 ◽  
Author(s):  
Marinela Peto ◽  
Oscar Aguilar-Rosas ◽  
Erick Erick Ramirez-Cedillo ◽  
Moises Jimenez ◽  
Adriana Hernandez ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Cell Attachment ◽  
Lattice Structure ◽  
Material Model ◽  
Patient Specific ◽  
Hexagonal Prism ◽  
Lattice Structures ◽  
Proof Of Concept

Abstract Lattice structures offer great benefits when employed in medical implants for cell attachment and growth (osseointegration), minimization of stress shielding phenomena, and weight reduction. This study is focused on a proof of concept for developing a generic shoulder hemi-prosthesis, from a patient-specific case of a 46 years old male with a tumor on the upper part of his humerus. A personalized biomodel was designed and a lattice structure was integrated in its middle portion, to lighten weight without affecting humerus’ mechanical response. To select the most appropriate lattice structure, three different configurations were initially tested: Tetrahedral Vertex Centroid (TVC), Hexagonal Prism Vertex Centroid (HPVC), and Cubic Diamond (CD). They were fabricated in resin by digital light processing and its mechanical behavior was studied via compression testing and finite element modeling (FEM). The selected structure according to the results was the HPVC, which was integrated in a digital twin of the biomodel to validate its mechanical performance through FEM but substituting the bone material model with a biocompatible titanium alloy (Ti6Al4V) suitable for prostheses fabrication. Results of the simulation showed acceptable levels of Von Mises stresses (325 MPa max.), below the elastic limit of the titanium alloys, and a better response (52 MPa max.) in a model with equivalent elastic properties, with stress performance in the same order of magnitude than the showed in bone’s material model.

Mechanical response of double-stranded DNA to dynamic excitation

2021 ◽  
pp. 107754632110458
Author(s):  
Hamze Mousavi ◽  
Moein Mirzaei ◽  
Samira Jalilvand
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Actual Condition ◽  
Dimensional System ◽  
One Dimensional ◽  
Linear Elastic ◽  
Dynamic Excitation ◽  
Double Stranded Dna ◽  
Elastic Forces ◽  
Mass Spring

The present work investigates the vibrational properties of a DNA-like structure by means of a harmonic Hamiltonian and the Green’s function formalism. The DNA sequence is considered as a quasi one-dimensional system in which the mass-spring pairs are randomly distributed inside each crystalline unit. The sizes of the units inside the system are increased, in a step-by-step approach, so that the actual condition of the DNA could be modeled more accurately. The linear-elastic forces mimicking the bonds between the pairs are initially considered constant along the entire length of the system. In the next step, these forces are randomly shuffled so as to take into account the inherent randomness of the DNA. The results reveal that increasing the number of mass-spring pairs in the crystalline structure decreases the influence of randomness on the mechanical behavior of the structure. This also holds true for systems with larger crystalline units. The obtained results can be used to investigate the mechanical behavior of similar macro-systems.

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