ABSTRACT
Objective@#To investigate the effects of electrochemically dealloying of Ti6Al4V abutments on human gingival fibroblasts (HGFs) and to provide experimental evidence for surface modification of implant abutments.@*Methods@#The samples were divided into an NC group (negative control, no other treatment on a smooth surface), an NM-1 group (nanomesh-1, electrochemical dealloying treatment in 1 mol/L NaOH 1 h on 2 V voltage), and an NM-2 group (nanomesh-2, electrochemical dealloying treatment in 5 mol/L NaOH 1 h on 2 V voltage). The surface morphologies of the samples and the adhesion of HGFs on the sample surfaces were observed with scanning electron microscopy (SEM). The surface hydrophilicities of the samples were measured with a contact angle measuring instrument. The proliferation of HGFs on the different samples were evaluated with CCK-8, and the expression of adhesion-related genes, including collagen Ⅰ (COL1A1), collagen Ⅲ (COL3A1), fibronectin 1 (FN1), focal adhesion kinase (FAK), vinculin (VCL), integrin α2 (ITGA2), and integrin β1 (ITGB1), on the different samples was measured with qRT-PCR. The expression of vinculin on the surfaces of HGFs was observed via confocal laser scanning microscopy (CLSM) after immunofluorescent staining. Collagen fiber secretion and syntheses of HGFs from different samples were evaluated via Sirius red staining.@*Results@#SEM revealed the formation of ordered and uniform three-dimensional mesh structures on the surfaces of the NM-1 and NM-2 groups, with grid diameters of approximately 30 nm for the NM-1 group and approximately 150 nm for the NM-2 group. Compared with that of the NC group, the water contact angles of the NM-1 group and NM-2 groups were significantly lower (P<0.000 1). Cell proliferation in the NM-1 group was significantly greater than that in the NC group (P<0.01). Moreover, there was no significant difference in the water contact angles or cell proliferation between the NM-1 group and the NM-2 group. SEM revealed that HGFs were adhered well to the surfaces of all samples, while the HGFs in the NM-1 and NM-2 groups showed more extended areas, longer morphologies, and more developed pseudopodia than did those in the NC group after 24 h. qRT-PCR revealed that the expression levels of the adhesion-related genes COL1A1, COL3A1, FN1, FAK and VCL in the NM-1 group were significantly greater than those in the NC and NM-2 groups (P<0.01). The expression of vinculin protein in the NM-1 group was the highest, and the number of focal adhesions was greatest in the NM-1 group (P<0.01). The results of Sirius red staining showed that the NM-1 group had the highest secretion and syntheses of collagen fibers (P<0.000 1).@*Conclusion@#The three-dimensional nanomechanical structure of Ti6Al4V modified by electrochemical dealloying promoted the adhesion, proliferation, collagen fiber secretion and syntheses of HGFs, and electrochemical dealloying of Ti6Al4V with a grid diameter of approximately 30 nm obviously promoted HGF formation.
ABSTRACT
Aiming at the medical practice problems of the surgical steel medical instruments, such as the crevice corrosion, the poor mechanical compatibility and the Ni, Cr plasma exudation, the laser deposition of Ti-6Al-4V alloy cladding layer at the local functional area as alternative coating was proposed and realized as a new process method. The accurate element content and good formability Ti-6Al-4V cladding powder was chosen, the low power and high duty cycle optimized laser process was adopt, the alternative coating of good fusion and low dilution was prepared. Through the elemental line scanning, the interface microstructure analysis and the experiments of basic mechanical properties, the basic properties of the cladding were characterized and verified. The experiments results showed that, the Ti, Al and V contents of the top coating were respectively about 88%, 4.9% and 3.9%, no sensitizing ions such as Cr and Ni were detected. Initial equiaxed α phase, flake β phase dist were distributed in the coating and interface, the α' martensite was precipitated at the boundary of the flake β phase, some refined granular β phase dispersion pinned to the grain boundary of basket structure. The microhardness of cladding layer was 352.08~312.76 HV0.1. The friction coefficient of the cladding layer was about 0.22~0.65. A new technology and method reference for improving and upgrading the performance of surgical medical devices is provided by this research.
Subject(s)
Alloys , Corrosion , Materials Testing , Steel , TitaniumABSTRACT
This research article gives an overview of the extensive research of Ti-6Al-4V from past few decades helped in studying about the features, properties, characteristics and application of aerospace industries. The final objective of study is to obtain the inherent advantages of Ti-6Al-4V like low elasticity modulus, high strength, low density and more resistant to fatigue and corrosion that leads to rely on the required knowledge for the employment of application which improves all physical and mechanical properties.
ABSTRACT
In maxillofacial surgery, there is a significant need for the design and fabrication of porous scaffolds with customizable bionic structures and mechanical properties suitable for bone tissue engineering. In this paper, we characterize the porous Ti6Al4V implant, which is one of the most promising and attractive biomedical applications due to the similarity of its modulus to human bones. We describe the mechanical properties of this implant, which we suggest is capable of providing important biological functions for bone tissue regeneration. We characterize a novel bionic design and fabrication process for porous implants. A design concept of “reducing dimensions and designing layer by layer” was used to construct layered slice and rod-connected mesh structure (LSRCMS) implants. Porous LSRCMS implants with different parameters and porosities were fabricated by selective laser melting (SLM). Printed samples were evaluated by microstructure characterization, specific mechanical properties were analyzed by mechanical tests, and finite element analysis was used to digitally calculate the stress characteristics of the LSRCMS under loading forces. Our results show that the samples fabricated by SLM had good structure printing quality with reasonable pore sizes. The porosity, pore size, and strut thickness of manufactured samples ranged from (60.95± 0.27)% to (81.23±0.32)%, (480±28) to (685±31) µm, and (263±28) to (265±28) µm, respectively. The compression results show that the Young’s modulus and the yield strength ranged from (2.23±0.03) to (6.36±0.06) GPa and (21.36±0.42) to (122.85±3.85) MPa, respectively. We also show that the Young’s modulus and yield strength of the LSRCMS samples can be predicted by the Gibson-Ashby model. Further, we prove the structural stability of our novel design by finite element analysis. Our results illustrate that our novel SLM-fabricated porous Ti6Al4V scaffolds based on an LSRCMS are a promising material for bone implants, and are potentially applicable to the field of bone defect repair.
ABSTRACT
Objective@#To investigate the physical properties of Ti-6Al-4V clasps generated by selective laser melting (SLM) with different construction directions and to compare these clasps with cast clasps, which could provide a basis for fabricating SLM clasps with high precision and excellent mechanical properties. @*Methods@# Ti-6Al-4V clasps were fabricated by SLM at 0 degrees (SLM0 group), 45 degrees (SLM45 group) and 90 degrees (SLM90 group) (n = 12). Twelve clasps were cast by the casting method as the control group. Meanwhile, four metal abutments were cast randomly as the abutments of the four groups. X-ray was used to detect cracks in the clasps of each group. The roughness of the clasps was measured by confocal microscopy, the fitness tests between clasps and abutment were processed by stereomicroscopy, and the microstructure of clasps in each group was observed under a metallographic microscope to evaluate the physical properties.@*Results @# There were 0-8 visible cracks in the casting group but no obvious defects in the SLM groups. The maximum surface roughness was observed in the cast group (18.102 ± 3.762) μm, while the minimum roughness was observed in the SLM90 group (5.942 ± 1.486) μm (P < 0.05). There was no statistically significant difference in surface roughness between the SLM0 group [(8.711 ± 2.378) μm] and the SLM45 group [(8.513 ± 1.161) μm]. Fitness was worst in the casting group [(68.445 ± 14.876) μm] and best in the SLM90 group [(33.417 ± 5.880) μm] (P < 0.05). There was no statistically significant difference in fitness between the SLM0 group [(52.917 ± 12.102) μm] and the SLM45 group [(50.889 ± 7.011) μm]. In addition, the growth direction of the β grains was roughly parallel to the build direction, and acicular α grains were present between β grains. SLM was composed of fine grains, while the cast group had large grains.@* Conclusions@# Specimens generated by SLM had finer grains than cast specimens. In addition, SLM90 clasps had the highest fitness and the lowest surface roughness.
ABSTRACT
The aim of this study was to examine the bioactivity and osseointegration of Ti-6Al-4V alloy implant which was modified by an anodic oxidation and a cyclic precalcification treatments. After blasting treatment using HAp (Hydroxyapatitie; HAp) powder which is resorbable blasting media (RBM) on the surface of Ti-6Al-4V alloy implants, the anodic oxidation treatment and the cyclic precalcification treatment were conducted to form nanotube TiO2 layer and HAp precipitation respectively. The surface morphology of the surface-treated Ti-6Al-4V alloy implant was investigated after immersion in the simulated body fluid(SBF) for 3 days to investigate the bioactivity. To investigate the effect of surface treatment on bonding between the implant and bone, RBM treated implant and RBM-anodization-cyclic precalcification(RACP) treated implant were placed on the distal side of both tibia diaphysis of rats, and then the removal torque of the implant was measured after 4 weeks. On the surface of RACP treated group, bone-like apatite precipitation was observed after immersion in SBF for 3 days. The removal torque was significantly higher in the RACP treated group than in the RBM treated group. The interfacial fracture between the implant and the new bone was observed in the RBM treated group, but both the cohesive fracture at the new bone and the interfacial fractures between the implant and the new bone were observed in the RACP treated group.
Subject(s)
Animals , Rats , Alloys , Diaphyses , Immersion , Nanotubes , Osseointegration , Tibia , TorqueABSTRACT
The paper outlines the achievements and challenges in the additive manufacturing (AM) application to veterinary practice. The state-of-the-art in AM application to the veterinary surgery is presented, with the focus of AM for patient-specifi c implants manufacturing. It also provides critical discussion on some of the potential issues design and technology should overcome for wider and more eff ective implementation of additively manufactured parts in veterinary practices. Most of the discussions in present paper are related to the metallic implants, manufactured in this case using so-called powder bed additive manufacturing (PB-AM) in titanium alloy Ti–6AL–4V, and to the corresponding process of their design, manufacturing and implementation in veterinary surgery. Procedures of the implant design and individualization for veterinary surgery are illustrated basing on the four performed surgery cases with dog patients. Results of the replacement surgery in dogs indicate that individualized additively manufactured metallic implants signifi cantly increase chances for successful recovery process, and AM techniques present a viable alternative to amputation in a large number of veterinary cases. The same time overcoming challenges of implant individualization in veterinary practice signifi cantly contributes to the knowledge directly relevant to the modern medical practice. An experience from veterinary cases where organ-preserving surgery with 3D-printed patient-specifi c implants is performed provides a unique opportunity for future development of better human implants.
Subject(s)
Animals , Dogs , Humans , Alloys , Amputation, Surgical , Osteosarcoma , Surgery, Veterinary , TitaniumABSTRACT
Additive manufacturing (AM) is an alternative metal fabrication technology. The outstanding advantage of AM (3D-printing, direct manufacturing), is the ability to form shapes that cannot be formed with any other traditional technology. 3D-printing began as a new method of prototyping in plastics. Nowadays, AM in metals allows to realize not only net-shape geometry, but also high fatigue strength and corrosion resistant parts. This success of AM in metals enables new applications of the technology in important fields, such as production of medical implants. The 3D-printing of medical implants is an extremely rapidly developing application. The success of this development lies in the fact that patient-specific implants can promote patient recovery, as often it is the only alternative to amputation. The production of AM implants provides a relatively fast and effective solution for complex surgical cases. However, there are still numerous challenging open issues in medical 3D-printing. The goal of the current research review is to explain the whole technological and design chain of bio-medical bone implant production from the computed tomography that is performed by the surgeon, to conversion to a computer aided drawing file, to production of implants, including the necessary post-processing procedures and certification. The current work presents examples that were produced by joint work of Polygon Medical Engineering, Russia and by TechMed, the AM Center of Israel Institute of Metals. Polygon provided 3D-planning and 3D-modelling specifically for the implants production. TechMed were in charge of the optimization of models and they manufactured the implants by Electron-Beam Melting (EBM®), using an Arcam EBM® A2X machine.
Subject(s)
Humans , Amputation, Surgical , Certification , Corrosion , Fatigue , Freezing , Israel , Joints , Metals , Methods , Plastics , Russia , TitaniumABSTRACT
PURPOSE: The purpose of this study was to investigate the corrosion behaviors of dental implant alloy after micro-sized surface modification in electrolytes containing Mn ion. MATERIALS AND METHODS: Mn-TiO₂ coatings were prepared on the Ti-6Al-4V alloy for dental implants using a plasma electrolytic oxidation (PEO) method carried out in electrolytes containing different concentrations of Mn, namely, 0%, 5%, and 20%. Potentiodynamic method was employed to examine the corrosion behaviors, and the alternating-current (AC) impedance behaviors were examined in 0.9% NaCl solution at 36.5℃±1.0℃ using a potentiostat and an electrochemical impedance spectroscope. The potentiodynamic test was performed with a scanning rate of 1.667 mV s⁻¹ from −1,500 to 2,000 mV. A frequency range of 10⁻¹ to 10⁵ Hz was used for the electrochemical impedance spectroscopy (EIS) measurements. The amplitude of the AC signal was 10 mV, and 5 points per decade were used. The morphology and structure of the samples were examined using field-emission scanning electron microscopy and thin-film X-ray diffraction. The elemental analysis was performed using energy-dispersive X-ray spectroscopy. RESULT: The PEO-treated surface exhibited an irregular pore shape, and the pore size and number of the pores increased with an increase in the Mn concentration. For the PEO-treated surface, a higher corrosion current density (I(corr)) and a lower corrosion potential (E(corr)) was obtained as compared to that of the bulk surface. However, the current density in the passive regions (I(pass)) was found to be more stable for the PEO-treated surface than that of the bulk surface. As the Mn concentration increased, the capacitance values of the outer porous layer and the barrier layer decreased, and the polarization resistance of the barrier layers increased. In the case of the Mn/Ca-P coatings, the corroded surface was found to be covered with corrosion products. CONCLUSION: It is confirmed that corrosion resistance and polarization resistance of PEO-treated alloy increased as Mn content increased, and PEO-treated surface showed lower current density in the passive region.
Subject(s)
Alloys , Corrosion , Dental Implants , Dielectric Spectroscopy , Electric Impedance , Electrolytes , Manganese , Methods , Microscopy, Electron, Scanning , Plasma , Spectrum Analysis , X-Ray DiffractionABSTRACT
Resumen: En este trabajo se presenta, la caracterización mediante las técnica de Infrarrojo, Microscopía de Fuerza Atómica, Microscopía Electrónica de Barrido y ángulo de contacto de los recubrimientos poliméricos de la mezcla binaria de policaprolactona-quitosano y su modificación tras la adición de colágeno que fueron depositados mediante la técnica de Dip Coating sobre la aleación de Ti6Al4V; además, se evaluó mediante la técnica de Espectroscopía de Impedancia Electroquímica la aleación Ti6Al4V recubierta por las mezclas de polímeros a cero días de inmersión en Fluido Corporal Simulado y la capacidad de adsorción de calcio a 21 días de inmersión. De esta manera, se encontraron efectos representativos sobre el papel del colágeno para el aumento de la rugosidad superficial, mayores valores en la resistencia a la polarización del Ti6Al4V, mejor comportamiento en los parámetros de energía libre, adsorción atómica de calcio y la consolidación de una nueva interfase asociada a la monocapa de calcio simulada mediante circuitos equivalentes y observada por Microscopía Electrónica de Barrido.
Abstract: This paper presents the characterization by the infrared technique, atomic force microscopy, scanning electron microscopy and contact angle of the polymer coatings of the binary mixture of polycaprolactone-chitosan and its modification after addition of collagen were deposited by the technique of Dip Coating on Ti6Al4V alloy; also by the technique of Electrochemical Impedance Spectroscopy were evaluated the Ti6Al4V alloy coated by polymer blends zero days immersion in Simulate Bode Fluid and of adsorptivity calcium to 21 days immersion. Thus, representative effects on the role of collagen to increase the surface roughness, higher values in the polarization resistance of Ti6Al4V, better behavior parameters free energy, atomic adsorption of calcium and the consolidation of a found new interface associated with the monolayer calcium simulated by equivalent circuits and observed by Scanning Electron Microscopy.
ABSTRACT
Abstract Introduction Various works have shown that diamond-like carbon (DLC) coatings are able to improve the cells adhesion on prosthesis material and also cause protection against the physical wear. On the other hand there are reports about the effect of substrate polishing, in evidence of that roughness can enhance cell adhesion. In order to compare and quantify the joint effects of both factors, i.e, polishing and DLC coating, a commonly prosthesis material, the Ti-6Al-4V alloy, was used as raw material for substrates in our studies of macrophage cell adhesion rate on rough and polished samples, coated and uncoated with DLC. Methods The films were produced by PECVD technique on Ti-6Al-4V substrates and characterized by optical profilometry, scanning electron microscopy and Raman spectroscopy. The amount of cells was measured by particle analysis in IMAGE J software. Cytotoxicity tests were also carried out to infer the biocompatibility of the samples. Results The results showed that higher the surface roughness of the alloy, higher are the cells fixing on the samples surface, moreover group of samples with DLC favored the cell adhesion more than their respective uncoated groups. The cytotoxity tests confirmed that all samples were biocompatible independently of being polished or coated with DLC. Conclusion From the observed results, it was found that the rougher substrate coated with DLC showed a higher cell adhesion than the polished samples, either coated or uncoated with the film. It is concluded that the roughness of the Ti-6Al-4V alloy and the DLC coating act complementary to enhance cell adhesion.
ABSTRACT
PURPOSE: The purpose of this study was to evaluate of Zirconium Nitride (ZrN) coating on shear bond strength with denture base resin in Co-Cr and Ti-6Al-4V alloy. MATERIALS AND METHODS: Co-Cr and Ti-6Al-4V alloy disks (10 mm in diameter, 2.5 mm in thickness; each other: n = 14) were prepared and divided with 2 groups each other by ZrN coating. After primer was applied to disks surface, denture base resin with diameter 6 mm, height 5 mm was bonded on metal disk surface. After surface roughness was measured by Profiler, shear bond strength was determined with Universal testing machine and analyzed with two-way ANOVA. The specimen surfaces and failure mode were examined using a scanning electron microscope. RESULTS: ZrN coated groups showed significantly higher rough surface than non-coated groups (P < 0.05). Irrespective of alloy materials, shear bond strength of ZrN coated groups were lower than non-coated groups (P < 0.001). The scanning electron microscope (SEM) of ZrN coated groups showed mixed and adhesive fractures. CONCLUSION: ZrN coating weakened bonding strength between denture base resin and Co-Cr, Ti-6Al-4V alloy.
Subject(s)
Adhesives , Alloys , Denture Bases , Dentures , Titanium , ZirconiumABSTRACT
The use of artificial implants provides a palliative or permanent solution for individuals who have lost some bodily function through disease, an accident or natural wear. This functional loss can be compensated for by the use of medical devices produced from special biomaterials. Titanium alloy (Ti-6Al-4V) is a well-established primary metallic biomaterial for orthopedic implants, but the toxicity of the chemical components of this alloy has become an issue of concern. In this work, we used the MTT assay and micronucleus assay to examine the cytotoxicity and genotoxicity, respectively, of an extract obtained from this alloy. The MTT assay indicated that the mitochondrial activity and cell viability of CHO-K1 cells were unaffected by exposure to the extract. However, the micronucleus assay revealed DNA damage and an increase in micronucleus frequency at all of the concentrations tested. These results show that ions released from Ti-6Al-4V alloy can cause DNA and nuclear damage and reinforce the importance of assessing the safety of metallic medical devices constructed from biomaterials.
Subject(s)
Biocompatible Materials , Cytotoxicity, Immunologic , Micronucleus Tests , Mutagenicity TestsABSTRACT
Purpose: Titanium alloys are commonly used for prosthetic abutments fabrication, but these alloys present high cost and difficult handling. Alternative Ni-Cr alloys with Mo and Ti combination have been proposed. This study compared the alloys Ti-6Al-4V and Ni-Cr-Ti-Mo by analyzing their surface properties such as hardness, morphology and microstructural characterization. Methods: Five discs (5 x 2 mm) of commercially Ti-6Al-4V and Ni-Cr-Ti-Mo alloys were used to evaluate Vickers hardness by hardness micro indentation test. The same specimens were analyzed by scanning electron microscopy (SEM) regarding surface morphology and subjected to a metallographic analysis of the microstructure by optical microscopy. Data on surface hardness were analyzed using one-way ANOVA followed by Tukey test (α = 0.05). Results: The Ni-Cr-Mo-Ti alloy showed significantly higher Vickers hardness (kg/mm2) values (452.2 ± 3.9) than the Ti-6Al-4V alloy (375.7 ± 15.2). The surface morphology evaluated by SEM revealed differences between the alloys. Metallographic analyses, for both alloys, showed a two-phase equilibrium microstructure, with the presence of e α + ß phase for Ti-6Al-4V; and gamma (γ) primary phase and gamma-prime (γ´) as a second phase for Ni-Cr-Mo-Ti. Conclusion: It can be concluded that both alloys present the requirements to be used in prosthetic abutments.
Objetivo: As ligas de titânio são comumente usadas para a fabricação de componentes protéticos, entretanto apresentam alto custo e dificuldade de manuseio laboratorial. Ligas alternativas a base de Ni-Cr combinadas com Mo e Ti também tem sido propostas com o mesmo objeto. Este estudo comparou as ligas Ti-6Al-4V e Ni-Cr-Ti-Mo pela análise de suas propriedades de superfície como dureza, morfologia e caracterização da microestrutura.Metodologia: Cinco discos (5 × 2 mm) das ligas Ti-6Al-4V e Ni-Cr-Ti-Mo foram utilizados para a avaliação da dureza Vickers, análise de morfologia de superfície por meio da microscopia eletrônica de varredura (MEV) e análise da microestrutura pela análise metalográfica. Os dados da dureza de superfície foram analisados pela Análise de Variância a um nível seguida do teste de Tukey (α = 0,05). Resultados: A liga Ni-Cr-Mo-Ti apresentou os maiores valores de dureza Vickers (kg/mm2) (452,2 ± 3,9) comparada a liga Ti-6Al-4V (375,7 ± 15,2) A morfologia de superfície avaliada por MEV revelou características distintas entre as ligas. A análise metalográfica para ambas as ligas mostrou uma microestrutura com equilíbrio de duas fases, com a presença de fase α + ß para Ti-6Al-4V; e fase gamma primária (γ) e fase gamma-prime (γ') como secundária para Ni-Cr-Mo-Ti. Conclusão: Ambas as ligas podem ser utilizadas para fabricação de pilares protéticos.
Subject(s)
Dental Alloys , Dental Prosthesis , HardnessABSTRACT
Objective To observe the effect of Ti-6AL-4V particles on morphological and func- tional changes of osteoclast in vitro.Methods Mature osteoclasts separated from New Zealand Rabbits were cultured on glass slices and cortical bone slices.The experimental group was stimulated by Ti-6AL- 4V particles at concentration of 0.1 mg/ml.The cells were stained with TRAP at different culture time to observe the morphological variety.The bone resorption pits on bone slices were stained by toluidine blue and the resorption areas analyzed by computer image analysis software.Results Osteoclasts phagocy- tosed the particles,with irregular shapes,deeper TRAP stain and earlier apoptosis.Stimulation by Ti- 6AL-4V particles brought about larger area of bone absorption lacuna.Conclusion Osteoclasts have the ability to phagocytose Ti-6AL-4V particles,which leads to morphological and functional changes and enhances bone resorption.