Use Of Bone Implants Research Articles

Feasibility of integrated numerical and Adaptive Neuro-Fuzzy Inference System models in predicting the thermophysical properties of unsteady coupled micropolar–Casson hybrid nanofluids

This article aims to probe postulated phenomena using a paired micropolar and Casson hybrid fluid over a rotating disk. The intension to design a numerical technique (Runge–Kutta fourth-order along with shooting technique) integrated Adaptive Neuro-Fuzzy Inference System (ANFIS) envisioned with a thermal and exponentially space-dependent heat source, nonlinear thermal radiation and entropy production is developed in this phase of work. To ensure that, a nonlinear partial differential equation set of equations has been transformed into an ordinary differential equation by using the proper self-similarity variables. The model's research results, with a few notable outliers, are mostly consistent with those from prior research that was merged into the dataset used to train the ANFIS model. With the impact of active factors, the results are esthetically exhibited for numerous profiles. This displays that with the rise in magnetic field and radiation, the velocity and temperature profiles increase sharply, resulting in a contradiction phenomenon with the decreasing electric field inputs. Also, tilting of vortex viscosity, spin gradient viscosity and microinertia density on the various microrotation components displays inclination. Moreover, ANFIS training was exploited to analyze the approximate solutions for specific scenarios, and the developed ANFIS was evaluated against a testing dataset to emphasize its performance. Due to their longer render, the nanoparticles exploited here are deemed suitable for use in bone implants, iodinated agents for blood imaging and red blood cell stimulation. Thus, the results of this study may be applied to therapeutic anemia therapies.

Microstructure, Mechanical Properties, In Vitro Biodegradability, and Biocompatibility of Mg-Zn/HA Composites for Biomedical Implant Applications.

Recently, Mg-Zn/hydroxyapatite (HA) composites have attracted much attention as potential candidates for use in bone implants. In this paper, the MgZn/HA composites were prepared using powder metallurgy (PM) and the merging mechanism of MgZn and HA particles was investigated by adjusting the weight ratio of the HA powder. The evolution of the HA distribution in the matrix was examined using SEM and micro-CT images. Afterward, the mechanical properties and biocompatibility of the composites were discussed in detail. The results revealed that the mechanical properties and biocompatibility of the Mg-Zn/HA composites were significantly affected by the HA content. Composites with a low HA content showed increased porosity, improved mechanical strength, and enhanced corrosion resistance after ball milling and cold pressing. These results underscore the importance of optimizing the HA content in Mg-Zn/HA composites for bone implants. Based on our findings, PM Mg-Zn/HA composites with a moderate HA content demonstrate the most promising characteristics as bone implants. The insights gained from this work contribute to the advancement of bone implant materials and hold great potential for enhancing orthopedic surgery outcomes.

Deep-learning-based inverse design of three-dimensional architected cellular materials with the target porosity and stiffness using voxelized Voronoi lattices

ABSTRACT Architected cellular materials are a class of artificial materials with cellular architecture-dependent properties. Typically, designing cellular architectures paves the way to generate architected cellular materials with specific properties. However, most previous studies have primarily focused on a forward design strategy, wherein a geometry is generated using computer-aided design modeling, and its properties are investigated experimentally or via simulations. In this study, we developed an inverse design framework for a disordered architected cellular material (Voronoi lattices) using deep learning. This inverse design framework is a three-dimensional conditional generative adversarial network (3D-CGAN) trained based on supervised learning using a dataset consisting of voxelized Voronoi lattices and their corresponding relative densities and Young’s moduli. A well-trained 3D-CGAN adopts variational sampling to generate multiple distinct Voronoi lattices with the target relative density and Young’s modulus. Consequently, the mechanical properties of the 3D-CGAN generated Voronoi lattices are validated through uniaxial compression tests and finite element simulations. The inverse design framework demonstrates potential for use in bone implants, where scaffold implants can be automatically generated with the target relative density and Young’s modulus.

Preliminary Study of Chemically Pretreated Densification of Juniper Wood for Use in Bone Implants

Kraft cooking of juniper wood with NaOH/Na2S aqueous solution has been used in the study for partial delignification at the temperature of 165°C for different residence time (0-40 min) following by thermal compression for densification under a pressure of 5 MPa at 100°C for 24 hours. The densified and natural juniper wood samples were characterized by chemical composition and mechanical properties. The results show that the density of densified juniper wood was increased by 96-127% reaching the value of 1170 kg/m3 that is similar to conventional bone implants (1090 kg/m3). Modulus of rupture and modulus of elasticity of densified juniper wood were increased by 85% and 621%, respectively, demonstrating a high potential of the material to be used as bone implants.

Coating of bone implants with silica, hyperbranched polyethyleneimine, and gentamicin prevents development of osteomyelitis in a porcine model

The use of bone implants and prostheses has contributed to a revolution in modern medicine; however, in the beginning, not much was asked from the implant and prosthetic materials per se. Therefore, the next game-changer in orthopedic research will come from new material designs which for instance can aid in prevention of implant-associated bone infections. Here, we describe the development of a new sol-gel coating technique that can deliver an efficient antimicrobial surface coating on orthopedic implants. Gentamicin was stocked in a novel nanocomposite xerogel made from silica and hyperbranched polyethyleneimine. The xerogel was anchored inside a porous surface made by coating of bone implants with titanium microspheres. Thereby, only the small water-soluble gentamicin molecules diffused in an aqueous environment, i.e., just after surgical insertion and leaving behind a titanium scaffold for osseointegration. The novel xerogel coating prevented development of severe Staphylococcus aureus induced osteomyelitis in a porcine model, which untreated, replicated the pathology seen in stage 3A on the Cierny–Mader classification system for osteomyelitis in adults.

Physicochemical and Biological Evaluation of Chitosan-Coated Magnesium-Doped Hydroxyapatite Composite Layers Obtained by Vacuum Deposition

In the present work, the effectiveness of vacuum deposition technique for obtaining composite thin films based on chitosan-coated magnesium-doped hydroxyapatite Ca10−xMgx(PO4)6 (OH)2 with xMg = 0.025 (MgHApCh) was proved for the first time. The prepared samples were exposed to three doses (0, 3, and 6 Gy) of gamma irradiation. The MgHApCh composite thin films nonirradiated and irradiated were evaluated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) studies. The biological evaluation of the samples was also presented. All the results obtained from this study showed that the vacuum deposition method allowed for obtaining uniform and homogeneous layers. Fine cracks were observed on the MgHApCh composite thin films’ surface after exposure to a 6 Gy irradiation dose. Additionally, after gamma irradiation, a decrease in Ca, P, and Mg content was noticed. The MgHApCh composite thin films with doses of 0 and 3 Gy of gamma irradiation showed a cellular viability similar to that of the control. Samples with 6 Gy doses of gamma irradiation did not cause significantly higher fibroblast cell death than the control (p > 0.05). On the other hand, the homogeneous distribution of pores that appeared on the surface of coatings after 6 Gy doses of gamma irradiation did not prevent the adhesion of fibroblast cells and their spread on the coatings. In conclusion, we could say that the thin films could be suitable both for use in bone implants and for other orthopedic and dentistry applications.

Additive manufacturing of biomimetic Titanium-Tantalum lattices for biomedical implant applications

Although additively manufactured titanium-tantalum alloys can offer unique mechanical and biological advantages for implant applications, their use in conjunction with engineered lattice architectures is yet to be explored. In the present study, the promising gyroid, diamond and Schwarz primitive minimal surfaces are used for the design of 3D lattices for biomedical implants. The lattices are fabricated using laser powder-bed fusion and a blend of elemental titanium-tantalum powder. The processability, compressive mechanical properties and in vitro biological properties of the dense and lattice samples are assessed via non-destructive and destructive characterization methods. The topologies from the designed structures are retained through processing and the compressive tests results show that the strength-to-modulus ratios are comparable to the conventional Ti-6Al-4 V alloy. However, the higher ductility and absence of toxic elements make the Ti-25Ta lattices a more favourable option for a new generation of implants. Compared to conventional lattices, the designs presented here also show advantageous mechanical properties for use in bone implants with higher elastic admissible strains. The in vitro cell cultures confirm the high biocompatibility of the material and improved biological response of the interconnected lattices over dense material.

A Critical Review of the Design, Manufacture, and Evaluation of Bone Joint Replacements for Bone Repair.

With the change of people’s living habits, bone trauma has become a common clinical disease. A large number of bone joint replacements is performed every year around the world. Bone joint replacement is a major approach for restoring the functionalities of human joints caused by bone traumas or some chronic bone diseases. However, the current bone joint replacement products still cannot meet the increasing demands and there is still room to increase the performance of the current products. The structural design of the implant is crucial because the performance of the implant relies heavily on its geometry and microarchitecture. Bionic design learning from the natural structure is widely used. With the progress of technology, machine learning can be used to optimize the structure of bone implants, which may become the focus of research in the future. In addition, the optimization of the microstructure of bone implants also has an important impact on its performance. The widely used design algorithm for the optimization of bone joint replacements is reviewed in the present study. Regarding the manufacturing of the implant, the emerging additive manufacturing technique provides more room for the design of complex microstructures. The additive manufacturing technique has enabled the production of bone joint replacements with more complex internal structures, which makes the design process more convenient. Numerical modeling plays an important role in the evaluation of the performance of an implant. For example, theoretical and numerical analysis can be carried out by establishing a musculoskeletal model to prepare for the practical use of bone implants. Besides, the in vitro and in vivo testing can provide mechanical properties of bone implants that are more in line with the implant recipient’s situation. In the present study, the progress of the design, manufacture, and evaluation of the orthopedic implant, especially the joint replacement, is critically reviewed.

Microstructure and improved anti-corrosion properties of cold-sprayed Zn coatings fabricated by post shot-peening process

To improve the corrosion resistance of Mg alloy, Zn coating was formed by cold spraying technology followed by post shot-peening processing. The phase structure, microstructure, and corrosion properties of the cold-sprayed Zn coatings before and after shot peening process were all investigated. The cold-sprayed Zn coating presented a porous and roughness structure. However, the Zn coatings after shot peening illustrated densifications with flattened and elongated Zn particles on the top layer. The mass and thickness losses of Zn coatings after shot peening both increased with the impact pressure owing to the competition between the densification and the erosion of Zn coatings. The microhardness of Zn coatings after shot peening increased from 40 HV0.025 to 64 HV0.025 due to factors like densification structure, work hardening, and grain refinement. It also displayed decreasing profiles from the surface to the inner bulk. The anti-corrosion properties of Zn coatings after shot-peening were improved by about one fold when compared to the cold-sprayed Zn coating owing to the presence of compact top layers. The corrosion changes in behaviors of Zn coatings before and after shot peening were clarified by comparing the morphologies and phase structures after immersion in stimulated body fluid. In sum, the proposed simple post-processing strategy looks promising for improving the corrosion resistance of cold-sprayed Zn coatings modified Mg alloy substrates, which might be useful for future use in bone implants.

Allograftinf in the case of revision hip arthroplasty at aseptic loosening of the acetabular component

Bone loss and significant acetabular defects remain one of the major problems in revision hip arthroplasty. A promising material for grafting of bone defects can be materials based on allogeneic bone after various types of processing, combining optimal properties for osteoregeneration. Objective. To analyze the results of acetabular reconstruction with bone implants «OMS-A» in the case of revision arthroplasty. Methods. The results of examination and treatment of 57 patients (33 women and 24 men) were analyzed. The patients’ age at the time of hospitalization ranged from 24 to 81 years. Patients were diagnosed on the basis of a combination of clinical ma­nifestations of the disease, laboratory data, radiography, computed tomography with 3D reconstruction. According to the classification of W. G. Paprosky, the largest group consisted of type I defects — 25 patients (44 %), II — 13 (23 %), III — 19 (33 %). For the reconstruction of the acetabulum, 21 patients (37%) we used fragmented cortical-cancellous pieces (CGP), 28 (49 %) — volumetric bone implants (OCI), 8 (14 %) — a combination of CGP and OCI. All patients underwent revision hip arthroplasty with an anterolateral approach according to Harding. The resulting acetabular defect was tightly filled with an allografts. Results. X-ray and G. A. Gie results were assessed as good in 36 patients (63 %), satisfactory — in 14 (25 %). The manifestations of infection associated with the use of bone implants «OMS-A» have not been determined. The necessity for repeated surgery in order to restore the acetabulum occurred in 7 patients (12 %). Conclusions. Тhe clinical efficiency of bone implants «OMS-A» for the reconstruction of the acetabulum according to the classification of W. G. Paprosky was: with type I defect — 92 %; with type I and type defect — 92.3 %; with type II and type defect — 78.9 %.

Nanostructured titanium dioxide for use in bone implants: a short review

Abstract Titanium dioxide (TiO2) based nanostructured materials have shown great potential for use in implants thanks to their excellent physicochemical properties, such as high specific surface area, ability to elicit positive cell response, and stability in body fluids. However, there are few studies in the literature that focus on the use of nanostructured TiO2 to support cell growth and bone regeneration. The purpose of this survey is to review the state of the art of TiO2 for use in bone implants, as well as provide insight into its characteristics and synthesis methods. Studies of the biological properties of nanostructured TiO2 are described, establishing its potential for the biomedical field.

Tribological properties of nanotubes grown on Ti-35Nb alloy by anodization

Nanotubes grown on titanium and its alloys can improve biocompatibility, surface wettability and corrosion resistance when compared to untreated materials. However, the tribological properties of these films are scarcely investigated. In this study, hardness and elastic modulus pure titanium and Ti-35Nb alloy were analyzed, while tribological properties of these materials were compared with those of nanotube films grown on Ti-35Nb alloy. The Ti-35Nb alloy, composed of alpha and beta phases, presented the higher hardness (3.7 GPa) and the lower elastic modulus (96 GPa) than the pure alpha‑titanium (2.3 GPa and 145 GPa, respectively). The coefficient of friction of the alloy was approximately 1.3, which was higher than that of titanium (~1.05). Analyses of the worn tracks revealed abrasive and adhesive wear mechanisms occurring in both titanium and Ti-35Nb alloy. However, the presence of beta phase was responsible for the strongest adhesion wear and the highest wear rate of the Ti-35Nb alloy. The nanotube films with approximately 1.0 μm thick were produced through controlled anodization. The tubes diameters were random; their composition was a TiO2 and Nb2O5 crystalline phases mixture. In reciprocating sliding tests, nanotubes were compacted on the surface, being damaged on the outer part of the film. However, the wear rate of surfaces with nanotube films was only 42% [(0.055 ± 0.012)·10−3 mm3/Nm] the value measured for the Ti-35Nb substrate [(1.661 ± 0.129)·10−3 mm3/Nm]. To summarize, the Ti35Nb alloy were more suitable than titanium, regarding mechanical properties, for use in bone implants; moreover, its tribological performance was enhanced through a lubricating effect provided by oxide nanotube films grown on it.

Comparing stiffness of solid and scaffold nano-TiO2 structures produced by material extrusion method

This study corresponds to the first stage of a project that focuses on optimizing the mechanical properties of titanium dioxide (TiO2) for use in bone implants. The goal of the study is to characterize and compare the stiffness of solid and scaffold TiO2 samples fabricated via three-dimensional material extrusion method.The sample specimens were sintered in a furnace at three different temperatures, namely-1200°C, 1250 and 1300°C- for 4h. The sintering procedure caused shrinkage in all dimensions and the maximum shrinkage (57.5%) was observed in the direction perpendicular to the work plate. The morphology of the sintered samples was analyzed via scanning electron microscopy. This revealed that increasing the sintering temperature increased the grain size and decreased porosity. For example, the porosity of the samples sintered at 1300°C was 20% less than that of samples sintered at 1200°C. Uniaxial compression tests showed that scaffold structures had a lower stiffness than their solid counterparts, and the decrease in stiffness was comparable to the reduction in cross-sectional area. The elastic modulus of TiO2 produced here by material extrusion was between 2.08–5.90GPa, which is close to the elastic modulus of high density cancellous bone at 0.8–1.5GPa. This is an important advantage as minimizing the mismatch in stiffness between bone and implant is critical to avoid problems such as stress shielding and bone resorption.

Role of surface finishing on the in vitro biological properties of a silicon nitride–titanium nitride (Si3N4–TiN) composite

Silicon nitride (Si3N4) has been introduced clinically as an orthopedic biomaterial for interbody fusion devices and in joint replacements. However, the production of complex shapes through conventional mechanical machining is difficult and expensive and limits interesting applications. Thus, several electrically conductive reinforcements to the Si3N4 matrix, like TiN, have been proposed, generating composites suitable to be wrought by electrical discharge machining (EDM). In this study, Si3N4–TiN with high strength, low density, and good electric conductivity wrought by EDM was studied. The role of surface finishing was investigated comparing the interface generated during the EDM process to that resulting from further polishing. The different topographical features were assessed by electron microscopy, energy dispersive X-ray spectrometry, and profilometry. Surface wettability was also determined based on the measurement of the OCA of water and diiodomethane. The biological responses induced in MC3T3 cells, a widely diffused osteoblast model, were correlated with the surface pattern. The unpolished samples could promote better cell viability, with a more relevant effect on the cytoskeleton arrangement as highlighted by numerous cytoplasmic extensions and filopodia-like structures and the high number of focal adhesions, while MC3T3 cells grown on polished Si3N4–TiN specimens displayed a flat morphology. In addition, the unpolished Si3N4–TiN increased osteocalcin production and calcium deposition. Taken together, these data support the biocompatibility and in vitro osteogenic properties of the electroconductive Si3N4–TiN investigated. Further in vivo studies are required to explore the possible use of bone implants directly obtained by EDM.

Direct Covalent Grafting of Phytate to Titanium Surfaces through Ti-O-P Bonding Shows Bone Stimulating Surface Properties and Decreased Bacterial Adhesion.

Myo-inositol hexaphosphate, also called phytic acid or phytate (IP6), is a natural molecule abundant in vegetable seeds and legumes. Among other functions, IP6 inhibits bone resorption. It is adsorbed on the surface of hydroxyapatite, inhibiting its dissolution and decreasing the progressive loss of bone mass. We present here a method to directly functionalize Ti surfaces covalently with IP6, without using a cross-linker molecule, through the reaction of the phosphate groups of IP6 with the TiO2 layer of Ti substrates. The grafting reaction consisted of an immersion in an IP6 solution to allow the physisorption of the molecules onto the substrate, followed by a heating step to obtain its chemisorption, in an adaptation of the T-Bag method. The reaction was highly dependent on the IP6 solution pH, only achieving a covalent Ti-O-P bond at pH 0. We evaluated two acidic pretreatments of the Ti surface, to increase its hydroxylic content, HNO3 30% and HF 0.2%. The structure of the coated surfaces was characterized by X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and ellipsometry. The stability of the IP6 coating after three months of storage and after sterilization with γ-irradiation was also determined. Then, we evaluated the biological effect of Ti-IP6 surfaces in vitro on MC3T3-E1 osteoblastic cells, showing an osteogenic effect. Finally, the effect of the surfaces on the adhesion and biofilm viability of oral microorganisms S. mutans and S. sanguinis was also studied, and we found that Ti-IP6 surfaces decreased the adhesion of S. sanguinis. A surface that actively improves osseointegration while decreasing the bacterial adhesion could be suitable for use in bone implants.

In vitro biocompatibility and ageing of 3Y-TZP/CNTs composites

The intrinsic brittleness of Tetragonal Zirconia Polycrystalline (TZP) materials has been the major barrier for their use in biocompatible orthopedic implants. Purpose of the current paper was to demonstrate that the material׳s toughness/hardness could be significantly improved with addition of carbon nanotubes (CNTs) to monolithic TZP. To verify possible application of the composites as implants, biocompatible responses of 3Y-TZP/CNTs was clarified in comparison with 3Y-TZP. The vitality, mineralization, and attachment status of osteoblast cells were studied by performing in vitro tests such as MTT assay, ALP assay, and SEM, respectively. Low-temperature degradation through 20h of heat treatment at 134°C and 3bar was studied to determine lifespan of the composites under humid atmosphere of human body conditions. Results showed suitable biocompatibility and negligible amount of low-temperature degradation. The synthesized TZP/CNTs composites, as a result, can be realized as adequate candidates for use in bone implants owing to their proper biocompatibility as well as a prolonged resistance against failure corroborating prominent mechanical properties compared to pure zirconia.

Evaluaton of the Use of Bone Implants as a Therapy for Deep Defects in the Parodoncium

ABSTRACT Reconstruction of infrabony defects created by the chronic inflammatory processes of parodontopathy represents a major clinical problem in paradontology. The objective of this research was to compare and evaluate the efficiency of two bone substituents at reversing the deep infrabony defects in the paradentium after the application of a new “Biohapel” material consisting of biphasic calcium phosphate/poly DL-lactide-co-glycolide. This study included 12 patients of both genders with an average age of 49.7 years who were suffering from clinically manifested parodontopathy. The main criteria for selecting patients were the presence of six similar infrabony periodontal defects that were at least 4 mm deep and in the lower side of the teeth on both sides of the jaw. After applying a basic causal parodontopathy treatment, defects were divided into two groups, including an experimental group (n=72) in which defects were reconstructed using the “Biohapel” bone substituent (on one side of the lower jaw) and a control group (n=72) in which infrabony defects were reconstructed using β tricalcium phosphate (βTCP) (CerasorbR), a preparation very commonly applied in regenerative parodontopathy treatment (on the other side of the lower jaw). Markers to assess treatment efficacy were determined before surgery and 6 months after surgery by measuring the depth of periodontal pocket and the level of the junctional epithelium. We observed statistically significant differences in the periodontal regeneration markers between the experimental and control groups (p<0.05). Application of “Biohapel” during the surgical treatment of infrabony defects in the paradentium significantly improves the bone regeneration of the paradentium when compared with the standard application of β-tricalcium phosphate .

Hydroxyapatite Biocomposites for Medical Use

New technological approaches based on biocompatible nanocomposites with hydroxyapatite (HA) and collagen matrix are described. Optimal conditions of HA synthesis in collagen fibers and its use in bone implants are discussed.

3D Assessment of Mandibular Growth Based on Image Registration: A Feasibility Study in a Rabbit Model

Background. Our knowledge of mandibular growth mostly derives from cephalometric radiography, which has inherent limitations due to the two-dimensional (2D) nature of measurement. Objective. To assess 3D morphological changes occurring during growth in a rabbit mandible. Methods. Serial cone-beam computerised tomographic (CBCT) images were made of two New Zealand white rabbits, at baseline and eight weeks after surgical implantation of 1 mm diameter metallic spheres as fiducial markers. A third animal acted as an unoperated (no implant) control. CBCT images were segmented and registered in 3D (Implant Superimposition and Procrustes Method), and the remodelling pattern described used color maps. Registration accuracy was quantified by the maximal of the mean minimum distances and by the Hausdorff distance. Results. The mean error for image registration was 0.37 mm and never exceeded 1 mm. The implant-based superimposition showed most remodelling occurred at the mandibular ramus, with bone apposition posteriorly and vertical growth at the condyle. Conclusion. We propose a method to quantitatively describe bone remodelling in three dimensions, based on the use of bone implants as fiducial markers and CBCT as imaging modality. The method is feasible and represents a promising approach for experimental studies by comparing baseline growth patterns and testing the effects of growth-modification treatments.

Technologies for Manufacturing Ultrahigh Molecular Weight Polyethylene-Based Porous Structures for Bone Implants

Efficacy of the use of bone implants and their reparative capacity are determined by the implant frame architecture. The implant should provide optimal ratio of porosity and pore size intended to maintain intensive pullulation of bone tissue. The goal of this work was to describe methods of formation of porous structure in ultrahigh molecular weight polyethylene (UHMWPE). The UHMWPE materials are intended for use in maxillofacial surgery. The following parameters of UHMWPE were estimated in this work: volume porosity, pore size, and mechanical characteristics of porous samples as functions of manufacturing procedures. Pore size was found to be determined by water-soluble filler, whereas mechanical characteristics depended on working pressure.