Titanium Specimens Research Articles

Repeated Exposure of Nanostructured Titanium to Osteoblasts with Respect to Peri-Implantitis.

Titanium offers excellent biocompatibility and extraordinary mechanical properties. As a result, it is used as a material for dental implants. Implants infected by peri-implantitis can be cleaned for successful re-osseointegration. Optimal surface properties, such as roughness and wettability, have a significant impact on cell adhesion. The aim of this study was to evaluate the adhesion and proliferation of osteoblasts on the surface of repeatedly cleaned nanostructured titanium samples. Human osteoblast-like cells MG-63 were seeded on nanostructured titanium specimens manufactured from rods produced by the equal channel angular pressing. For surface characterization, roughness and wettability were measured. Cell adhesion after 2 h as well as cell proliferation after 48 h from plating was assessed. We have found that this repeated cleaning of titanium surface reduced cell adhesion as well as proliferation. These events depend on interplay of surface properties, such as wettability, roughness and topography. It is difficult to distinguish which factors are responsible for these events and further investigations will be required. However, even after the several rounds of repeated cleaning, there was a certain rate of adhesion and proliferation recorded. Therefore the attempts to save failing implants by using in situ cleaning are promising.

Plastic strain localization in surface-hardened titanium polycrystals

In this paper, features of plastic strain localization in commercial purity titanium surface-hardened by ultrasonic impact treatment (UIT) are numerically investigated. Three- dimensional polycrystalline structures inherent in unhardened and UIT surface-hardened titanium specimens are generated by a step-by-step packing method. For taking into account the deformation mechanisms at the micro- and mesoscales, constitutive equations describing a nonlinear behavior of individual grains are constructed using crystal plasticity theory. Quasi-static boundary value problems are solved in a dynamic statement using ABAQUS\\Explicit finite-element package to simulate uniaxial tension of the model polycrystalline specimens. Based on the calculation results, conclusions are drawn on the effect of the UIT surface- hardened layer on the plastic strain localization and deformation-induced surface roughening in model polycrystals.

In Vitro Toxic Effect of Biomaterials Coated with Silver Tungstate or Silver Molybdate Microcrystals

Purpose. This study evaluated the cytotoxicity of antimicrobial silver tungstate (Ag2WO4) or silver molybdate (Ag2MoO4) microcrystals coating biomaterials. Materials and Methods. The coating procedure was performed onto titanium, zirconia, and acrylic resin specimens. Eluates of the coated specimens were obtained, which were used for cytotoxicity analyses, including Alamar Blue, MTT, and CytoTox-ONE tests. Data were analyzed using two-way ANOVA, followed by the Tukey test (α = 0.05). The results of each experimental group were also compared to those of the control of living cells, taken as 100% cell viability. Results. In general, it was observed that the percentage of living cells from all biomaterials coated with both microcrystals was statistically different compared to the ones from the uncoated sample groups, except for the results from MTT of specimens of Ti coated with α-Ag2MoO4. All uncoated biomaterials were classified as noncytotoxic by the three assays used in the present study. It was observed that the microcrystals in solution were strongly cytotoxic, with death of almost 100% of cells, from the analysis of the results of the Alamar Blue assay. Conclusion. The most biomaterials coated with both microcrystals showed some degree of cytotoxicity in the different assays. The results described herein should be seen as an alert to the use of microcrystals, which can expose patients to health risks.

Comparative investigation of ultrasonic cavitation erosion for three materials in deionized water

To investigate the response of material to cavitation erosion, a comparative work was carried out on three materials, aluminum, copper alloy and titanium. Ultrasonic cavitation erosion was produced as the specimen was submerged in the deionized water. Within a cavitation erosion period of 120 min, the cumulative mass loss was measured at certain time intervals. Surface structure and cavitation damage patterns were observed for the three materials. Microhardness was measured and compared. The results indicate that the cumulative mass loss of aluminum is the highest among the three materials, while the slightest material removal is associated with titanium, which is still in the initial stage of cavitation erosion after 120 min of cavitation erosion. The surface of the aluminum specimen is eroded rapidly after the cavitation erosion commences. Large erosion pits dominate the eroded surface as the cavitation erosion progresses. The surface of the titanium specimen manifests needle-like erosion pits and cleavage cracks. Even at the later stage of the cavitation erosion, non-eroded surface elements are identifiable. The cavitation erosion pattern on the copper alloy specimen surface is related to the twin-phase crystal structure and large erosion pits are produced at the later stage of cavitation erosion. The highest resistance to the cavitation erosion of titanium is related to the close-packed hexagonal structure and the weak slip effect associated.

The biocompatibility and mechanical properties of plasma sprayed zirconia coated abutment.

PURPOSEThe aim of this study was to evaluate the clinical performance and reliability of plasma sprayed nanostructured zirconia (NSZ) coating.MATERIALS AND METHODSThis study consisted of three areas of analysis: (1) Mechanical property: surface roughness of NSZ coating and bond strength between NSZ coating and titanium specimens were measured, and the microstructure of bonding interface was also observed by scanning election microscope (SEM). (2) Biocompatibility: hemolysis tests, cell proliferation tests, and rat subcutaneous implant test were conducted to evaluate the biocompatibility of NSZ coating. (3) Mechanical compatibility: fracture and artificial aging tests were performed to measure the mechanical compatibility of NSZ-coated titanium abutments.RESULTSIn the mechanical study, 400 µm thick NSZ coatings had the highest bond strength (71.22 ± 1.02 MPa), and a compact transition layer could be observed. In addition, NSZ coating showed excellent biocompatibility in both hemolysis tests and cell proliferation tests. In subcutaneous implant test, NSZ-coated plates showed similar inflammation elimination and fibrous tissue formation processes with that of titanium specimens. Regarding fatigue tests, all NSZ-coated abutments survived in the five-year fatigue test and showed sufficient fracture strength (407.65–663.7 N) for incisor teeth.CONCLUSIONIn this study, the plasma-sprayed NSZ-coated titanium abutments presented sufficient fracture strength and biocompatibility, and it was demonstrated that plasma spray was a reliable method to prepare high-quality zirconia coating.

Mechanical properties of titanium matrix composites fabricated via powder metallurgy method

The betterment of properties in the material can be enhanced by means of composite technology. The composite technology applied in the matrix of polymers as well as metals by reinforcement. This research comes under the classification of metal matrix composite. The titanium is widely used material. The properties of titanium proposed to reinforce by a limited weight percentage of boron carbide and graphite. The selected quantity of boron carbide 5 wt% and graphite 5 wt% used to reinforce the titanium by means of powder metallurgy technology. The prepared specimens of titanium and TMMC (reinforced with boron carbide and graphite) prepared by the processes of ball milling, compacting and sintering. The specimens included for microscopy examinations, hardness and compression investigations. The results presented and discussed in detail. The Optical Micrograph image ensures uniform distribution of reinforced particles in the matrix material.

Effect of different surface treatments on the shear bond strength of luting cements used with implant-supported prosthesis: Anin vitrostudy

PURPOSEThe aim of this study was to investigate the shear bond strength of luting cements used with implant retained restorations on to titanium specimens after different surface treatments.MATERIALS AND METHODSOne hundred twenty disc shaped specimens were used. They were divided into three groups considering the surface treatments (no treatment, sandblasting, and oxygen plasma treatment). Water contact angle of specimens were determined. The specimens were further divided into four subgroups (n=10) according to applied cement types: polycarboxylate cement (Adhesor Carbofine-AC), temporary zinc oxide free cement (Temporary Cement-ZOC), non eugenol provisional cement for implant retained prosthesis (Premier Implant Cement-PI), and non eugenol acrylic-urethane polymer based provisional cement for implant luting (Cem Implant Cement-CI). Shear bond strength values were evaluated. Two-way ANOVA test and Regression analysis were used to statistical analyze the results.RESULTSOverall shear bond strength values of luting cements defined in sandblasting groups were considerably higher than other surfaces (P<.05). The cements can be ranked as AC > CI > PI > ZOC according to shear bond strength values for all surface treatment groups (P<.05). Water contact angles of surface treatments (control, sandblasting, and plasma treatment group) were 76.17° ± 3.99, 110.45° ± 1.41, and 73.80° ± 4.79, respectively. Regression analysis revealed that correlation between the contact angle of different surfaces and shear bond strength was not strong (P>.05).CONCLUSIONThe retentive strength findings of all luting cements were higher in sandblasting and oxygen plasma groups than in control groups. Oxygen plasma treatment can improve the adhesion ability of titanium surfaces without any mechanical damage to titanium structure.

Effect of Shot Peening on the Mechanical Properties and Cytotoxicity Behaviour of Titanium Implants Produced by 3D Printing Technology.

Structural discontinuities characterize the implants produced directly from metal powders in 3D printing technology. Mainly, the surface defects should be subjected to procedures associated with surface layer modification (likewise shot peening) resulting in the increase of the implant service life maintaining optimal biocompatibility. Therefore, the purpose of the present study was to investigate the effect of type of shot used for the peening process on the Ti-6Al-4V implants functional properties as well as the biological properties. The components were produced by DMLS (direct metal laser sintering) additive technology. The surfaces of titanium specimens have been subjected to the shot peening process by means of three different shots, i.e., CrNi steel shot, crushed nut shells, and ceramic balls shot. Then, the specimens have been subjected to profilometric analysis, microhardness tests, and static strength testing as well as to the assessment of biocompatibility in respect of cytotoxicity using human BJ fibroblasts. The shot peening process causes the strengthening of surface layer and the increase of strength parameters. Furthermore, the test results indicate good biocompatibility of surfaces being tested, and the effect of shot peening process on the titanium alloy cytotoxicity is acceptable. At the same time, most favourable behaviour in respect of cytotoxicity has been found in the case of surfaces modified by means of ceramic balls > nut shells > CrNi steel shot correspondingly.

Comparative study of in vitro apatite-forming abilities of highly ordered rutile nanorod arrays fabricated on cpTi and Ti6Al4V alloys

ABSTRACTThe surfaces of commercially available pure titanium (cpTi) and Ti6Al4V alloy specimens were modified to form highly ordered rutile nanorod arrays by chemical treatment and subsequent aging treatment. The densities of the rutile rods were (1.04 ± 0.06) ×103 and (0.70 ± 0.10) ×103 μm–2 for the cpTi and Ti6Al4V alloy specimens, respectively. Both the rutile nanorod arrays on the cpTi and Ti6Al4V alloy specimens deposited apatite particles when soaked in simulated body fluid (SBF) for one day. After soaking for various other periods, scanning electron microscopy images and thin-film X-ray diffraction patterns of these specimens showed that the cpTi specimens exhibited a superior rate of apatite nucleation and favored the formation of numerous apatite particles with larger diameter. This superior apatite-forming ability of the cpTi specimens can be attributed to the dense, thick titania layers with higher rutile nanorod density on their surfaces.

Thermal Transformation of the Surface of Mn-, W-Containing Plasma Electrolytic Oxide Coatings on Titanium

Thermal behavior of the surface of coatings formed on titanium specimens by plasma electrolytic oxidation (PEO) in phosphate—borate—tungstate electrolyte containing manganese acetate as a precursor was studied. High-temperature annealing in air allows directional obtaining of ensembles of nano- and microcrystals of definite composition and geometry on the surface of specimens with multicomponent PEO coatings.

Poly(methyl methacrylate) Coating of Titanium Workpieces to Reduce Burrs in Micro-drilling.

A technique to reduce burr height in titanium micro-drilling is presented: a poly (methyl methacrylate) coating was applied before machining on the upper and lower surfaces of a titanium specimen (0.5-mm thick). After drilling, a cleaning process (acetone bath) was executed to eliminate the coating, and holes with less burr were obtained. The coating process was executed with a spin-coating machine. To test the efficacy of the technique, two different coating thicknesses (7.9 and 5.4 μm) and two drill bits (0.25- and 0.5-mm diameter) were evaluated. Qualitative and quantitative analyses of the holes obtained were performed with scanning electron microscopy and three-dimensional microscopy, respectively. The results highlight the efficacy of the technique to reduce the burr height by 70% in coated titanium relative to that in an uncoated titanium sheet.

Biological Effects of Plasma-Based Graphene Oxide Deposition on Titanium

This study was performed to investigate the effects of argon plasma treatment under atmospheric pressure at room temperature on the cytotoxicity and antimicrobial effects of the graphene oxide layer on titanium. Plasma treatment of the graphene oxide coating on a nonthermal atmospheric-pressure plasma device was performed. Raman spectrum analysis confirmed that graphene oxide was successfully coated on the surface and AFM analysis confirmed that this coating affected the surface roughness. X-ray photoelectron spectroscopy (XPS), Alizarin Red S staining for cell differentiation, and Raman and atomic force microscopy (AFM) analyses were performed for the deposited surface. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was performed to confirm the biocompatibility of the plasma-treated and bare titanium specimens. The biofilm formation test usingStreptococcus mutans(S. mutans) was performed to examine potential antimicrobial effects. XPS analysis showed that with increasing plasma coating time, the carbon content of the surface decreased while that of oxygen increased. Alizarin Red S staining showed that the cell differentiation was promoted by the deposition of the graphene oxide. The graphene oxide on Ti significantly affected an osteoblast cell differentiation for bone growth, and no significant differences in antimicrobial effects were observed.

Effect of polygon order on additively manufactured lattice structures: a method for defining the threshold resolution for lattice geometry

Additive manufacture (AM) enables the fabrication of highly efficient lattice structures. However, the mathematical efficiency of characterising AM lattice geometry can be poor, potentially restricting the commercial application of AM lattice structures. This research quantifies the effect of the polygon order used to characterise the geometric resolution of lattice strut elements on the associated manufacturability and geometric qualities of the manufactured lattice. The effect of these design parameters on manufactured quality is experimentally determined for aluminium and titanium specimens fabricated by selective laser melting (SLM), although the method can be generally applied to any AM technology. This research finds that geometric thresholds exist, below which additional geometric resolution does not result in increased part quality. These thresholds are a function of material, lattice inclination angle, cross-sectional area and the polynomial order used to represent the cross section. These findings enable significantly reduced computational cost in managing AM lattice structures, and can be directly integrated with algorithmic methods for the optimisation of AM lattice structures.

Linear elastic finite element investigation of titanium specimen produced by Additive Manufacturing

Nowadays orthopaedic implants are mainly fabricated from solid material (titanium alloy). The mechanical properties of these implants are much stronger than human bone tissue’s properties, and this leads to fixation problems and a short lifetime, but today these problems can be eliminated with the usage of metal additive manufacturing. The mechanical properties of the implants can be influenced on demand with the variation of the material structure using different sizes and types of unit cells for building up its structure.

Fatigue life prediction for rotary friction welded Ti-6Al-4V under variable amplitude fatigue loading

The present paper considers variable amplitude fatigue lifing for rotary friction welds in Grade 23 6Al-4V titanium alloy. The work reported in this paper aimed firstly at optimising the parameters necessary to successfully rotary weld 6 mm diameter hourglass specimens of Ti-6Al-4V and, secondly, at generating CA stress-life (S-N) fatigue data to underpin a VA fatigue life prediction that was then experimentally verified against the results obtained from VA fatigue testing using an 3200 turning point sequence extracted from the simulated aircraft load spectrum mini-FALSTAFF (a modified Fighter Aircraft Loading Standard for Fatigue). It was found that the real damage sum Dreal=(Dspec/Ls)*N‾exp was significantly <1.0 for both parent alloy and welded specimens and also varied with maximum stress amplitude. Taking a damage sum value of 1.0 as representing failure in fatigue life prediction would therefore be grossly nonconservative for these Grade 23 6Al-4V titanium specimens under spectrum VA loading, irrespective of whether they are in the parent plate or rotary friction welded condition.

Early prediction of macroscale plastic strain localization in titanium from observation of mesoscale surface roughening

The numerical and experimental investigations have been performed to establish a correlation between local strains and mesoscale deformation-induced surface roughening in commercial purity titanium specimens. The evolution of surface profiles in selected regions of the specimens is examined in the course of uniaxial tension. Complementing the experimental studies, crystal plasticity finite-element simulations of deformation-induced surface roughening are performed for a model polycrystal. It has been shown that a series of out-of-plane surface displacements characterized by different amplitudes and frequencies are formed in the experimental and computational specimens under tension. Roughening intensifies on a larger scale when smaller length scale deformation mechanisms are exhausted. In order to quantify the multiscale surface patterns a dimensionless roughness parameter has been proposed. Unlike the traditional methods of roughness assessment, unfiltered profiles are analyzed to take into account the deformation mechanisms that are at work at different length scales. The dimensionless roughness parameter is shown to be sensitive to and well correlated with the local plastic strains. In the region of macroscopic necking, the mesoscale roughness begins to increase nonlinearly well ahead of the visible evidence of the macroscale strain localization, while in the other regions it ceases to increase at all. The results support the assumption that the plastic strain localization and fracture can be predicted early from estimations of mesoscale surface roughness.

Effect of different surface treatments on the repair bond strength of resin composites with titanium

The purpose of this study was to evaluate the effect of different surface treatment combinations on the bonding of composite resins to NiCr and titanium alloys after thermal cycling. Square-shaped specimens (10 mm x 10 mm x 2 mm) were made from NiCr and titanium alloys. The specimens were divided into 6 pretreatment groups (n = 11): (1) machined titanium (control, no treatment); (2) CoJet sand application; (3) grinding with a diamond bur; (4) metal primer application; (5) CoJet sand + metal primer application; and (6) grinding with a diamond bur + metal primer application. The surface roughness of the mechanically treated specimens (control, grinding, CoJet sand) was evaluated. The surface morphology of both metals and elemental composition were examined with SEM and EDS. The composite resin was applied to the specimens. Shear bond strength (SBS) was tested after thermal cycling (5000 cycles, 5 °C to 55 °C). Failure modes were determined. The data were analyzed using the Shapiro-Wilk test, two-way ANOVA and post hoc Fisher’s LSD test (p = .05). For titanium specimens, the grinding + metal primer exhibited higher values than the other groups, and all groups showed higher SBS values than the control group. Combined use of CoJet sand, grinding with a diamond bur, and metal primer application would be useful for enhancing the bond strength of composite resin to titanium. The grinding of the NiCr surface with a diamond bur is the only method that could improve the bond strength of a composite resin compared to the other methods.

Doxorubicin - chitosan - hydroxyapatite composite coatings on titanium alloy for localized cancer therapy.

The doxorubicin-chitosan composite is deposited electrochemically on the Ti alloy post hydroxyapatite coated for reducing the side effects by sustaining release of drugs localized near the tumor to achieve the inhibition or apoptosis of cancer. The possibility of danger in case of exfoliation of medicine composite and HA agglomerates from the alloy surface due to the dynamic erosion of blood flow could be overcome with the additional surface modification by the electrochemical deposition way. The cathodic polarization tests coupled with electrochemical reactions were analyzed to speculate the deposition mechanism of doxorubicin, spectrophotometer (UV visible spectrometer) to measure doxorubicin loading and release, field emission scanning electron microscope (FESEM) to observe surface morphology, Fourier transform infrared (FTIR) spectroscopy for chemical bonding of composites, and X-ray diffractometry (XRD) for crystal structure. The cell culture was carried out to analyze the drug efficacy on cell viability. It is concluded that doxorubicin-chitosan composites can be successfully deposited on the uncoated and hydroxyapatite-coated titanium specimen alloy by electrochemical methods. Both have revealed the sustaining drug release for a month and the latter with high porosity can enhance the drug loading to 37.46 μg/cm2, revealing this electrochemical method is a practical way to load doxorubicin cancer drug releasing locally to significantly reduce the amount of medication needed for future clinical applications.

The Effect of Ultraviolet Photofunctionalization on a Titanium Dental Implant with Machined Surface: An In Vitro and In Vivo Study.

Ultraviolet (UV) photofunctionalization has been suggested as an effective method to enhance the osseointegration of titanium surface. In this study, machined surface treated with UV light (M + UV) was compared to sandblasted, large-grit, acid-etched (SLA) surface through in vitro and in vivo studies. Groups of titanium specimens were defined as machined (M), SLA, and M + UV for the disc type, and M + UV and SLA for the implant. The discs and implants were assessed using scanning electron microscopy, confocal laser scanning microscopy, electron spectroscopy for chemical analysis, and the contact angle. Additionally, we evaluated the cell attachment, proliferation assay, and real-time polymerase chain reaction for the MC3T3-E1 cells. In a rabbit tibia model, the implants were examined to evaluate the bone-to-implant contact ratio and the bone area. In the M + UV group, we observed the lower amount of carbon, a 0°-degree contact angle, and enhanced osteogenic cell activities (p < 0.05). The histomorphometric analysis showed that a higher bone-to-implant contact ratio was found in the M + UV implant at 10 days (p < 0.05). In conclusion, the UV photofunctionalization of a Ti dental implant with M surface attained earlier osseointegration than SLA.

Application of Different Diffraction Peak Profile Analysis Methods to Study the Structure Evolution of Cold-Rolled Hexagonal α-Titanium

This paper presents a comparison between the “classical” and the modified Williamson–Hall and Warren–Averabach methods applied to an analysis of the microstructure of $$\alpha$$-titanium. The microstructural parameters of cold-rolled titanium specimens were retrieved from analysis of the X-ray diffraction (XRD) peaks. The high-quality XRD patterns were received at the P07 beamline (The High Energy Materials Science) at the German electron synchrotron. The dependence of the crystallite size, the inhomogeneous microstrains, the average dislocation density, the dislocation cut-off radius and some other parameters on the plastic strain were estimated. The results clearly indicate that, due to the consideration of the dislocation contrast effect, the modified models are a much better fit to the experimental data in comparison with the “classical” models. The results of hardness and corrosion resistance measurements of Ti samples can be explained based on the results obtained from the XRD analysis.