DMP1 and IFITM5 Regulate Osteogenic Differentiation of MC3T3-E1 on PEO-Treated Ti-6Al-4V-Ca2+/Pi surface

Despite numerous studies on various surface modifications on titanium and its alloys, it remains unclear what kind of titanium-based surface modifications are capable of controlling cell activity. This study aimed to understand the mechanism at the cellular and molecular levels and investigate the in vitro response of osteoblastic MC3T3-E1 cultured on the Ti-6Al-4V surface modified by plasma electrolytic oxidation (PEO) treatment. A Ti-6Al-4V surface was prepared by PEO at 180, 280, and 380 V for 3 or 10 min in an electrolyte containing Ca²⁺/P_i ions. Our results showed that PEO-treated Ti-6Al-4V-Ca²⁺/P_i surfaces enhanced the cell attachment and differentiation of MC3T3-E1 compared to the untreated Ti-6Al-4V control but did not affect cytotoxicity as shown by cell proliferation and cell death. Interestingly, on the Ti-6Al-4V-Ca²⁺/P_i surface treated by PEO at 280 V for 3 or 10 min, MC3T3-E1 showed a higher initial adhesion and mineralization. In addition, the alkaline phosphatase (ALP) activity significantly increased in MC3T3-E1 on the PEO-treated Ti-6Al-4V-Ca²⁺/P_i (280 V for 3 or 10 min). In RNA-seq analysis, the expression of dentin matrix protein 1 (DMP1), sortilin 1 (Sort1), signal-induced proliferation-associated 1 like 2 (SIPA1L2), and interferon-induced transmembrane protein 5 (IFITM5) was induced during the osteogenic differentiation of MC3T3-E1 on the PEO-treated Ti-6Al-4V-Ca²⁺/P_i. DMP1 and IFITM5 silencing decreased the expression of bone differentiation-related mRNAs and proteins and ALP activity in MC3T3-E1. These results suggest that the PEO-treated Ti-6Al-4V-Ca²⁺/P_i surface induces osteoblast differentiation by regulating the expression of DMP1 and IFITM5. Therefore, surface microstructure modification through PEO coatings with Ca²⁺/P_i ions could be used as a valuable method to improve biocompatibility properties of titanium alloys.

Nanotube Morphology Changes of Ti-xTa-Ag-Pt Alloys with Ta Content for Biomaterials

In this study, nanotube morphology changes of Ti-xTa-Ag-Pt alloys with Ta content for biomaterials were researched using various experimental instruments. Ti-xTa-Ag-Pt alloys were manufactured in an Ar atmosphere using a vacuum arc-melting furnace with Ta contents of 10 and 50, and then heat-treated at 1100 °C for 1 hr. Nanotube formation of Ti-xTa-Ag-Pt (x = 10, 50 wt%) alloys were performed using a DC power of 30 V in 1.0 M H₃PO₄ + 0.8 wt% NaF electrolyte solution. Surface characteristics were investigated using an optical microscope, X-ray diffractometer, field-emission scanning electron microscope, energy-dispersive X-ray spectroscopy, and Image analyzer (Image J). Ti-10Ta-Ag-Pt alloy had a needle-like structures, and Ti-Ti-50Ta-Ag-Pt showed the mixed structure (equiaxed and needle-like structures). As the Ta content increased, the α-phase decreased and the β-phase increased. The highly ordered nanotubes were formed on the β-phase, whereas disordered nanotubes were formed on needle-like structure of α-phase in Ti-10Ta-Ag-Pt alloy. As the Ta content increases, large and small nanotube diameters became smaller in size. Anatase and rutile phases were formed on the alloy surface. Ta, Ag, and Pt elements were uniformly distributed over the entire surface and at the edge or inside of the nanotube.

Electrochemical Analysis of Nano- and Micro-Sized Pore Formed Ti-6Al-4V Alloys in Solution Containing Ca, P, Mn, and Si Ions via Plasma Eletrolytic Oxidation for Bio-Implant Materials

The purpose of this study was to investigate electrochemical analysis of nano- and micro-sized pore formed Ti-6Al-4V alloys in solution containing Ca, P, Mn and Si ions via plasma eletrolytic oxidation for bio-implant materials. The coatings were produced on Ti-6Al-4V alloy for dental implant using the plasma electrolytic oxidation (PEO) method in electrolytes with the various concentration of 0, 5, and 20% Mn and Si, respectively. Electrochemical potentiodynamic polarization and AC impedance behaviors were carried out in 0.9% NaCl solution at 36.5 ± 1 °C using potentiostat (Potentiostat, EG&G, 362) and electrochemical impedance spectroscope (EIS, EG&G, 1025). The potentiodynamic polarization test with a scan rate of 1.667 mV s^-1 was carried out from -1500 mV to 2000 mV. The frequency range used for EIS was 10²-10⁵ Hz. The amplitude of AC signal was 10 mV and 5 points per decade was used. From the potentiodynamic polarization test, PEO treated alloy in electrolyte containing Ca, P, Mn, and Si show a lower corrosion potential than that on the bulk surface. In the case of Mn and Si doped surface, the corrosion resistance increase compared to non-doped surface with Mn and Si elements, and the current density was lower than that of the bulk surface. From the AC impedance test, in the case of Mn and Si doped surface, polarization resistance values were higher than other specimens, and nano- and micro-sized pores were covered with corrosion product consisted Mn and Si elements.

Nano/Micro-Sized Morphologies of Hydroxyapatite Coatings Containing Mn and Si on an Oxidized Ti-6Al-4V Alloy Surface for Dental Implants

To improve the surface characteristics of Ti-6Al-4V dental implants and the binding between the bone and implant surface, biocompatible oxide films were formed by plasma electrolytic oxidation (PEO). The PEO treatment was performed using electrolyte solutions containing Ca (calcium acetate monohydrate), P(calcium glycerophosphate), Mn (manganese(II) acetate tetrahydrate), and Si (sodium metasilicate nonahydrate), which are the major constituents of bone, for 3 min at 280 V. The morphology and crystalline phase of the PEO-treated surfaces were characterized using field-emission scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, and Fourier transform infrared spectroscopy. All the obtained PEO-treated samples exhibited a morphology comprising porous structures. Oval and irregular pore structures were observed as the Mn content increased. As the Si content increased, the areas occupied by the pores increased. When both, Si and Mn were used for the PEO treatment, the number of nano- to micro-sized pores gradually decreased with the increasing ratios of the constituents.

Plasma Electrolytic Oxidation on Ti-xNb-2Ag-2Pt Alloys for Nano- and Micro-Pore Formation in Electrolyte with Ca and P Ions for Dental Implant Use

In this study, plasma electrolytic oxidation (PEO) on Ti-xNb-2Ag-2Pt alloys for nano- and micro-pore formation in electrolyte with Ca and P ions for dental implant use was studied using various experimental equipment. The Ti-xNb-2Ag-2Pt alloys were fabricated using a vacuum arc melting furnace, and micro-pores were created through PEO-treatment in an electrolyte containing Ca and P ions. The PEO-treated surface was observed by X-ray diffractometer (XRD), field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy (EDS). The microstructure of Ti- xNb-2Ag-2Pt alloys showed the transformation of needle-like structure to equiaxed structure, as Nb content increased. Adding small amounts of Ag and Pt to Ti-xNb alloys, microstructure was not observed the significantly difference compared to Ti-xNb. The nano- and micro-pore sizes increased as the Nb content increased after PEO-treatment of Ti-xNb. In the case of Ti-50Nb-2Ag-2Pt, groove structure was observed, also the Ca/P ratio increased as the Nb content increased. The oxide layer thickness of Ti-xNb-2Ag-2Pt alloys was increased, as the Nb content increased.

Nanotube Morphology Changes on the Ti-xNb-Ag-Pt Alloy with Nb Contents

The purpose of this study was to investigate the nanotube morphology changes of Ti-xNb-Ag-Pt alloys with Nb content. Ti-xNb-Ag-Pt was fabricated using arc melting vacuum furnace. The Ti- xNb-Ag-Pt ingot was further homogenized in an Ar atmosphere at 1100 °C for 1 h in a vacuum and then quenched at 0 °C. Nanotube formation on the samples was performed using anodization method with a DC power supply at 30 V for 2 h in 1 M H₃PO₄ +0.8 wt.% NaF at 25 °C. The surface morphology was observed using OM, FE-SEM, EDS, and XRD. In the microstructure of Ti-xNb-Ag-Pt alloy, needle-like structures on α and α″ gradually disappeared with increasing Nb, β-phase equilibrium structure appeared, and particle size decreased. The nanotube morphology of the Ti-xNb-Ag-Pt alloy changed according to the content of Nb. As the Nb content increases, the highly ordered nanotubes have changed to irregular nanotubes. The difference in dissolution area at the bottom of the nanotube was depending on the Nb content.

Surface Observation of Plasma Electrolytic Oxidation-Treated Ti-6Al-4V Alloy After 2-Step Nano-Mesh Formation

The purpose of this study was to investigate the surface observation of PEO-treated Ti-6Al-4V alloy after 2-step nano-mesh formation was investigated by FE-SEM, EDS, and XRD. Anodic oxidation treatment was performed on the electrolyte containing 0.8 wt.% Na/F and 1M H₃PO₄ to form a nanotube structure on the Ti-6Al-4V alloy. After removing the nanotube layer, PEO-treatment was performed on the electrolyte containing Mg and Zn ions. After forming the nanotubes, the nanomesh surface was obtained by removing the layer, and the surface roughness increased with cycle number of nanotube formation. Also, as the number of nanotubes increased, the anatase peak increased.

Corrosion Behaviors of Zn, Si, and Mn-Doped Hydroxyapatite Coatings Formed on the Ti-6Al-4V Alloy by Plasma Electrolytic Oxidation

Ti alloy for implant materials is not good biocompatibility between metal implants and natural bone without surface modification. In order to improve the bone attachment ability, implant surface modification is required, and corrosion resistance is also important when a surface modified implant is inserted into the body. In this study, corrosion behaviors of anodic oxide film formed on Ti-6Al-4V alloy with concentration of Mn and Zn ions were studied using various experimental techniques. Ti-6Al-4V ELI disk were used as the substrate for PEO treatment. The sample was used a anodic electrode and PEO treatment was carried out by varying the content of each of the electrolytic solutions containing Zn, Mn, Si, Ca and P, using a Pt bar as a cathodic electrode. Pulsed DC power was used at 280 V for 3 min. For the corrosion behaviors of the specimens, the potentiodynamic polarization and AC impedance test were carried out in 0.9% NaCl solution. From the result of experiments, as Zn ion content increases, the number of pores and the pore size increase. As the Mn ion increases, the number of pores decreases, while the pore size increases. As the ions of Mn increase, the corrosion potential decreases. As Zn ion content increased, the polarization resistance increased.

Highly Ordered Nanotube Formation on Beta Typed Ti-xTa Alloy Surface

In this study, the highly ordered nanotube formation on beta typed Ti-xTa alloy surface was investigated. The Ti-xTa binary alloys were manufactured using a vacuum arc-melting furnace with varying Ta contents (10, 30, and 50 wt%), and then homogenized by heat treatment at 1050 °C for 1 h. The nanotube formation of Ti-xTa (x = 10-50 wt%) alloys were performed using a DC power source of 30 V in 1.0 M H₃PO₄ + 0.8 wt% NaF electrolyte solution for 2 hrs. The surface characterization was performed using field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The microstructure of Ti-xTa alloy showed martensite structure α', α″-phase, and a '-phase structure. As the Ta content increased, the needle-like structures of α' and α'-phase gradually disappeared and only the equiaxed structure of β-phase appeared. Nanotube morphology of Ti-xTa alloy changed according to Ta content. As the Ta content increased, the size of the nanotubes decreased and the number of the smaller nanotubes increased. In the cross-sectioned nanotube layer, the gap size between the nanotubes decreased as the Ta content increased.

Functional Elements Coatings on the Plasma Electrolytic Oxidation-Treated Ti-6Al-4V Alloy by Electrochemical Precipitation Method

In this study, functional elements coatings on the plasma electrolytic oxidation (PEO)-treated Ti-6Al-4V alloy by electrochemical precipitation method were investigated. Ti-6Al-4V ELI disks were used as specimens for PEO and HA coating. The applied voltage and time were selected to be 280 V and 3 minutes for PEO treatment, respectively. The electrochemical precipitation on the Ti-6Al-4V alloy was carried out using cyclic voltammetry with cycle of 3, 5, 10, and 20 from -1.5 V to 0 V (vs. SCE electrode) in electrolyte containing Ca, P, Mg, Mn, Sr, Zn, and Si ions by cyclic voltammetry after PEO treatment. The morphology changes of the coatings on the PEO treated Ti-6Al-4V alloy surface were observed using FE-SEM and EDS. PEO surface has a uniformly distributed circular shape and a porous surface and the deposition of low cycles in electrolyte containing Mg, Mn, Sr, Zn, and Si-HA coated surfaces show uniform circular and granular structures. The precipitates of Mg, Mn, Sr, Zn, and Si-HA on the PEO treated surface showed a large number of circular particles as the number of deposition cycles increases with a mixture of rod-shaped particles and petal-shaped particles around pores. The precipitate nucleates around the pore and grows rapidly as the cycles increase.

Functional Elements Coatings on Ti-6Al-4V Alloy by Plasma Electrolytic Oxidation for Biomaterials

In this study, functional elements coatings on Ti-6Al-4V alloy by plasma electrolytic oxidation for biomaterials were studied using various experimental techniques. For this study, Ti-6Al-4V ELI disk (grade 5, Timet Co. Ltd., Japan diameter; 10 mm) were used as the substrate for PEO treatment in the electrolyte containing Ca, P, Si, Zn, and Mn ions. The PEO treatment was performed using a pulsed DC power supply at 280 V for 3 min. The PEO-treated surface was observed with field-emission scanning electron microscope (FE-SEM), and energy dispersive X-ray spectrometry (EDS; Oxford ISIS 310, England), Image Analyzer software, and X-ray diffractometer (TF-XRD, X'pert Philips, Netherlands). The number of pores increases, as the Zn ion content increases. And the number of pores decrease, as the Mn ion content increases. The addition of Zn and Mn ions affects the number and size of pores and the area occupied by the pores. Mn and Zn are distributed around pores and in the pores. Anatase and rutile peaks appear and the HA peak shifted to the left in the case of Mn and Zn ion additions.

A Simulated Body Fluid Evaluation of TiO₂ Barrier Oxide Layer Formed by Electrochemical Reaction

The modified surface during implantation is considered to be an effective strategy to improve high adhesion of bone cell and osseointegration activity. In this paper, the TiO2 barrier oxide Layer has been fabricated by using the ion characteristic of an electrolytic solution, the surface characteristics have been investigated by EDS, XPS, and FE-SEM. From the analysis of the chemical states, phosphorus and calcium were observed in the TiO2 barrier layer, which were penetrated from the electrolyte into the oxide layer during deposit process. In addition, Ca 2p spectrum was identified into two peaks for Ca 2p3/2 and 2p1/2 at 347.4 and 351.3 eV, which are related to hydroxyapatite. Also, P spectrum was confirmed into two peaks for P1/2 and P3/2 levels with binding energy 134.2 and 133.4 eV, respectively. Thus, the incorporated phosphate species were found mostly in the forms of HPO-4, PO-3. From the result of biological evaluation in simulated body fluid (SBF), the apatite morphologies were effective for bioactive property on the modified surface.

Electrochemical Deposition of Hydroxyapatite Substituted with Magnesium and Strontium on Ti-6Al-4V Alloy

In the present study, electrochemical deposition of hydroxyapatite substituted with magnesium and strontium on Ti-6Al-4V alloy have investigated. Mg and Sr-doped HAp was coated using subsequently pulsed electrochemical deposition process at 85 °C in the solution contained Ca, Mg, Sr, and P ion. The morphology of Mg/Sr-HAp formed on implant was investigated using scanning electron microscopy and X-ray diffraction. HAp grain size and XRD intensity decreased with Mg2+ and Sr2+ ions. The initial current density was changed with addition of Mg and Sr ion concentration when the constant voltage was applied to specimens. The morphologies and phase of HAp coated layers were affected by the Mg and Sr ion concentration. Results suggest that Mg/Sr-HAp layer formed on Ti can be a potential candidate for dental materials application.

Pore Shape Changes and Apatite Formation on Zn and Si Ion-Doped HA Films of Ti-6Al-4V After Plasma Electrolytic Oxidation Treatment

In this study, pore shape changes and apatite formation on zinc (Zn) and silicon (Si) ion-doped hydroxyapatite (HA) films of Ti-6Al-4V by plasma electrolytic oxidation (PEO) treatment has been investigated by several techniques. The PEO films and the Ti-6Al-4V surface after immersion in SBF were observed by X-ray spectroscopy, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. The number of pores decreased as Zn ion concentration increased from 5Zn to 10Zn. The maximum size of pores were increased from 5Zn to 20Zn concentration, whereas, the minimum size of pores decreased. The amount of bone-like apatite formation for the 5Zn/5Si sample was higher than those of other samples immersed in SBF.

Hydroxyapatite Coatings Containing Mn and Si on the Oxidized Ti-6Al-4V Alloy for Dental Applications

The purpose of this study was to investigate hydroxyapatite coatings containing Mn and Si on the oxidized Ti-6Al-4V alloy for dental applications. Dental implant fixture and Ti-6Al-4V ELI disk were used as substrates for plasma electrolytic oxidation (PEO) treatment. PEO treatment was performed at 280 V for 3 min in various solutions. The surface morphologies of the specimens after PEO treatment were observed with a field-emission scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffractometer, and Fourier transform infrared spectroscopy. The breakdown potential for pore formation depended on the added ions in electrolytes. Rough surface with micro-pores was formed after plasma discharge in the electrolytes containing Si and Mn ions. The surface morphologies of implant fixtures were covered with manganese-silicon compounds, as Mn concentration increased. From the XRD analysis, anatase peaks decreased, as Mn and Si contents increased. From the results of FT-IR analysis, Si-HA and Mn-HA was formed on the implant surface.

Morphology Changes of Plasma Electrolytic Oxidized Ti-6Al-4V Alloy in the Electrolytes Containing Sr and Si Ions

In this study, morphology changes of plasma electrolytic oxidized (PEO) Ti-6Al-4V alloy in the electrolytes containing Sr and Si ions were researched using field-emission scanning electron microscope, Image J program thin film X-ray diffraction, and energy dispersive X-ray spectroscopy. Pulsed DC power supplied Ti-6Al-4V alloy was used at a 280 V for 3 minutes in the electrolyte containing Sr and Si ions. To determine cell growth, human embryonic kidney cells 293 were grown at a density of 2 × 105 cells per 1.0 ml in well plates. The pore size decreased, as the content of Sr ion increased, whereas, the number of pores per area increased. The Ca/P ratio of PEO treated in electrolyte containing high Sr concentration showed the higher than those of in electrolyte containing low Sr concentration. The peak of HA is shifted to left side, as the concentration of Sr increased. Also, the number of cells increased, as the concentration of Sr increased.

Surface Characteristics of Nanotube Formed Ti–25Nb–xZr Alloys

The purpose of this study was to investigate surface characteristics of nanotube formed Ti–25Nb–xZr alloys. Ti–25Nb–xZr ternary alloys with 0–15 wt% Zr were manufactured in a vacuum arcmelting furnace. Ingots of the alloys were homogenized in an Ar atmosphere at 1000 °C for 12 h, followed by quenching in ice water. Nanotube layers were formed by an electrochemical method in 1 M H₃PO₄ and 0.8 wt% NaF at 30 V for 1 h. As the Zr content of the Ti–25Nb–xZr Alloys increased, the crystals transformed from a needle-like to equiaxed structure. Two nanotube sizes were obtained on the Ti–25Nb–xZr alloys. As the Zr content was increased, the diameters of the larger tubes decreased, whereas those of the smaller tubes increased. However, increased Zr content in the Ti–25Nb–xZr alloys had little effect on wettability.

Effects of Electrolyte Concentration on Formation of Calcium Phosphate Films on Ti–6Al–4V by Electrochemical Deposition

Nano-sized calcium phosphate film was formed on Ti–6Al–4V alloy using simple electrochemical deposition. Pre-treatment of Ti–6Al–4V alloy was carried out by galvanostatic treatment step which acted as anchorage for growth of the hydroxyapatite during subsequent pulsed electrochemical deposition process at 40 and 85 °C. The phase and morphologies of deposited calcium phosphate were influenced by the electrolyte temperature and electrolyte ratio (Ca/P). The nano needle-like precipitates were formed under 1.67 Ca/P ratio in solution. The needle-like deposits were transferred to the plate-like precipitates in the case of Ca-deficient or Ca-rich electrolyte.

Phenomena of Nano- and Micro-Pore Formation on Ti-(10~50)Ta Alloys by Plasma Electrolytic Oxidation for Dental Implants

In this study, the phenomena of nano and micro-pore formation on Ti-(10~50)Ta alloys by plasma electrolytic oxidation for dental implants was investigated using various experimental techniques. The Ti–xTa alloys having Ta contents of 10, 30, and 50 wt.% were prepared using arc-melting vacuum furnace. Micro-pore formation was performed using a potentiostat in 1 M H₃PO₄ electrolyte by using a potentiostat at various applied voltage (180 V, 210 V, and 240 V). The microstructure of Ti–xTa alloys changed from α′ phase to β + α″ phase with Ta content increased. The applied potential increased, the numbers of micro-pore per unit area decreased, whereas the area ratio of occupied by micro-pores increased. The Ta contents increased, the numbers of micro-pore per unit area decreased, whereas the area ratio of occupied by micro-pores increased at 210 V and 240 V. The thickness of oxide layer and micro-pore size can be controlled by applied potential.

Biocompatibility and Degradation of a Low Elastic Modulus Ti-35Nb-3Zr Alloy: Nanosurface Engineering for Enhanced Degradation Resistance

In this study, the biocompatibility and degradation behavior of a low elastic modulus Ti-35Nb-3Zr alloy were investigated and compared with that of the conventional orthopedic and dental implant materials, i.e., commercially pure titanium (Cp-Ti) and Ti-6Al-4V alloy. The biocompatibility test results suggested that cells proliferate equally well on Ti-35Nb-3Zr and Cp-Ti. The degradation rates of Cp-Ti and Ti-6Al-4V were ∼68% (p < 0.05) and ∼84% (p < 0.05) lower as compared to Ti-35Nb-3Zr, respectively. Interestingly, the passive current density (i_{pass (1000mv)}) of the Ti-35Nb-3Zr alloy was ∼29% lower than that of Cp-Ti, which suggests that the alloying elements in the Ti-35Nb-3Zr alloy have contributed to its passivation behavior. Nanosurface engineering of the Ti-35Nb-3Zr alloy, i.e., a two-step electrochemical process involving anodization (producing nanoporous layer) and calcium phosphate (CaP) deposition, decreased the degradation rate of the alloy by ∼83% (p < 0.05), and notably, it was similar to the conventional Ti-6Al-4V alloy. Hence, it can be suggested that the nanosurface-engineered low elastic modulus Ti-35Nb-3Zr alloy is a promising material for orthopedic and dental implant applications.

Effect of different grinding burs on the physical properties of zirconia

PURPOSE

Grinding with less stress on 3Y-TZP through proper selection of methods and instruments can lead to a long-term success of prosthesis. The purpose of this study was to compare the phase transformation and physical properties after zirconia surface grinding with 3 different grinding burs.

MATERIALS AND METHODS

Forty disc-shaped zirconia specimens were fabricated. Each Ten specimens were ground with AllCeramic SuperMax (NTI, Kahla, Germany), Dura-Green DIA (Shofu Inc., Kyoto, Japan), and Dura-Green (Shofu Inc., Kyoto, Japan). Ten specimens were not ground and used as a control group. After the specimen grinding, XRD analysis, surface roughness test, FE-SEM imaging, and biaxial flexural strength test were performed.

RESULTS

After surface grinding, small amount of monoclinic phase in all experimental groups was observed. The phase change was higher in specimens, which were ground with Dura-Green DIA and AllCeramic SuperMax burs. The roughness of surfaces increased in specimens, which were ground with Dura-Green DIA and AllCeramic SuperMax burs than control groups and ground with Dura-Green. All experimental groups showed lower flexural strength than control group, but there was no statistically significant difference between control group and ground with Dura-Green DIA and AllCeramic SuperMax burs. The specimens, which were ground with Dura- Green showed the lowest strength.

CONCLUSION

The use of dedicated zirconia-specific grinding burs such as Dura-Green DIA and AllCeramic SuperMax burs decreases the grinding time and did not significantly affect the flexural strength of zirconia, and therefore, they may be recommended. However, a fine polishing process should be accompanied to reduce the surface roughness after grinding.

Surface Characteristics of Nano-Structured Silicon/Hydroxyapatite Deposition onto the Ti-Nb-Zr Alloy

The Ti-Nb-Zr alloy was manufactured with 35 wt% of Nb and 10 wt% of Zr by arc melting furnace to be a beta phase. Electrochemical deposition of Si substituted Ca/P was performed by pulsing the potential with a method of cyclic voltammetry, and changed cyclic time between 10, 30, 70, and 150. The electrolyte was prepared by dissolving the reagent-grade chemicals: Ca(NO3)2, NH4H2PO4, and Na2SiO3 x 9H20 to be 1.67 of Ca/P ratio and silicon contents were controlled to be 1 wt%. The surface characteristics were observed by field-emission scanning electron microscopy, X-ray diffractometer, and electrochemical corrosion as a potentiodynamic test. The Si substituted hydroxyapatite layer was successfully formed on the Ti-35Nb-10Zr alloy substrate by electrochemical deposition. A surface morphologies showed needle like shape at 10 cycles, then changed to be a circular with increment of cycles. The Ca/P ratio was the range between 1.5 and 2.0, the crystalline of hydroxyapatite could be confirmed. The corrosion behavior of Si-HA deposition was related with surface shape and thickness by increment, of cyclic times. Higher cyclic times of deposition had higher corrosion potential and current density than that of lower cyclic surface.

Biocompatibility of Mg Ion Doped Hydroxyapatite Films on Ti-6Al-4V Surface by Electrochemical Deposition

In this study, we prepared magnesium (Mg) doped nano-phase hydroxyapatite (HAp) films on the TiO2 nano-network surface using electrochemical deposition method. Ti-6Al-4V ELI surface was anodized in 5 M NaOH solution at 0.3 A for 10 min. Nano-network TiO2 surface were formed by these anodization steps which acted as templates and anchorage for growth of the Mg doped HAp during subsequent pulsed electrochemical deposition process at 85 degrees C. The phase and morphologies of HAp deposits were influenced by the Mg ion concentration.

Electrochemical Deposition of Si-Ca/P on Nanotube Formed Beta Ti Alloy by Cyclic Voltammetry Method

The purpose of this study was to investigate electrochemical deposition of Si-Ca/P on nanotube formed Ti-35Nb-10Zr alloy by cyclic voltammetry method. Electrochemical deposition of Si substituted Ca/P was performed by pulsing the applied potential on nanotube formed surface. The surface characteristics were observed by field-emission scanning electron microscopy, X-ray diffractometer, and potentiodynamic polarization test. The phase structure and surface morphologies of Si-Ca/P deposition were affected by deposition cycles. From the anodic polarization test, nanotube formed surface at 20 V showed the high corrosion resistance with lower value of Icorr, I300, and Ipass.

Nano-Particle Formation of Mn/HA on the Ti-35Ta-xNb Alloy by Electrochemical Methods

In this study, nano-particle formation of Mn/HA on the Ti-35Ta-xNb alloy by electrochemical methods has researched using various experiments. These alloys were performed by arc-melting furnace and then heat treated for 1000 °C at 12 h in Ar gas atmosphere and quenched at 0 °C water. Hydroxyapatite precipitation has been synthesized from 5 mM Ca(NO3)2 · 4 H2O+3 mM NH4H2PO4 at 80±1 °C. Manganese doped Hydroxyapatite precipitation has been synthesized from 4.95 mM Ca(NO3)2 · 4 H2O+3 mM NH4H2PO4+0.05 mM MnCl2 · 4 H2O at 80±1 °C. Morphology and structure were examined by FE-SEM, EDS and XRD. The microstructure of Ti-35Ta-xNb alloys was transformed from a phase to α phase as Nb content increased. The nano-scale HA shapes were plate-like precipitates and Mn doped HA shapes were net-like precipitates on Ti-35Ta-xNb alloys, and Ca, P and Mn peaks were detected on the Mn/HA deposited surface.

Electrochemical Characteristics of Cell Cultured Ti-Nb-Zr Alloys After Nano-Crystallized Si-HA Coating

The aim of this study was to investigate the electrochemical characteristics of nano crystallized Si-HA coating on Ti-Nb-Zr alloy after human osteoblast like (HOB) cell attachment. The Ti-Nb-Zr alloy was manufactured with 35 wt.% of Nb and 10 wt.% of Zr by arc melting furnace to appropriate physical properties as biomaterials. The HA and Si-substituted coatings were prepared by electron-beam physical vapor deposition method with 0.5, 0.8 and 1.2 wt.% of Si contents, and nano aging treatment was performed 500 degrees C for 1 h. The characteristics of coating surface were analyzed by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction, respectively. To evaluate of cell attachment on cell cultured surface, the potentiodynamic test was performed on the surface using HOB cells. The results showed that the Si-HA coating surface showed higher tendency of cell attachment than that of single HA coating, corrosion resistance value was increased by dense of cell attachment.

Nanotubular Structure on the Ti-29Nb-5Zr Alloy by Scanning Transmission Electron Microscope

In this study, we reported the observation of highly ordered nanotubular structure on the Ti-29Nb-5Zr alloy in various potentials and electrolytes by field emission scanning electron microscopy and scanning transmission electron microscope. From the X-ray diffraction results and microstructure analysis, Ti-29Nb-5Zr alloy had β phase. The nanotube morphologies of Ti-29Nb-5Zr alloy were transformed from nano-porous structure to nanotube structure as NaF concentration and voltage increased. Nanotube diameter and layer changed with different concentration of NaF in 1 M H3PO4 at the same voltage. From the X-ray photoelectron spectroscopy results, nanotube was formed by Nb, Zr, and Ti oxide. Also, barrier layer of large tube was about 50 nm thickness, small one was 60 nm thickness. The nanotube size and crystallinity on the β Ti alloy was controlled by fluoride concentration, applied potential, anodization time, and tube layer.

Nanotube Nucleation Phenomena of Titanium Dioxide on the Ti-6Al-4V Alloy Using Anodic Titanium Oxide Technique

The purpose of this study was to investigate nanotube nucleation phenomena of titanium dioxide on the Ti-6Al-4V alloy were investigated using anodic titanium oxide technique. Heat treatment was performed at 1000 degrees C for 12 hour for formation of α+/β phase and water quenched. Ti-6Al-4V alloy was anodized in 1 M H3PO4 electrolytes containing 0.8 wt.% NaF at room temperature. After formation of nanotube was achieved, nanotube layer was eliminated, and then anodization was carried out repeatedly. The microstructures, phase transformation, and morphology of nanotubular Ti-6Al-4V alloy was examined by optical microscopy, X-ray diffraction (XRD), field emission scanning electron microscopy and atomic force microscopy. Microstructures of Ti-6Al-4V alloy showed the β structure with a phase. From XRD pattern of Ti-6Al-4V alloy after heat treatment, β peak was increased, whereas, a peak was decreased. The surface morphology appeared regular nanotube on a phase, whereas, nanotube morphology was not shown on the β phase. α and β phases were affected to form the nanotube of Ti-6Al-4V alloy.

The Control of Nanotube Morphology Using Various Factors for Dental Implant

The purpose of this study was to investigate the control of nanotube morphology using various factors for dental implant. TiO2 nanotube formation on biomedical grade α+β type Ti-6Al-4V alloy was investigated using anodization technique as a function of applied DC potential (10 V to 30 V and 30 V to 10 V) and anodization time for 60 min in 1 M H3PO4 with small additions of NaF (0.5 wt.%, and 0.8 wt.%). The microstructure and phase characteristics of surface were examined by optical microscopy, field emission scanning electron microscopy and X-ray diffraction. Also, in order to observe the biocompatibility and surface roughness, wettability and atomic force microscopy of alloy was measured.

AC impedance behaviors of electrochemically deposited Si-hydroxyapatite films on nanotube-formed Ti-Nb-Zr alloys

The aim of this study was to investigate the AC impedance behaviors of electrochemically deposited Si-hydroxyapatite (HA) films on nanotube-formed Ti-Nb-Zr alloys by the cyclic voltammetry method. Surface modifications were carried out sequentially during nanotube formation and the application of Si-HA coatings. The nanotube surface formed at 10 V had a smaller diameter than that of the nanotube surface formed at 20 V, and the nanotube surface formed at 20 V had a denser pore structure as compared to the nanotube surface formed at 10 V. The Si-HA coating of nanotube surfaces formed at 10 V exhibited flower- and plate-like layers, and the nanotube surface formed at 20 V had larger flower- and plate-like shapes. After 30 deposition cycles, the Si-HA coating showed more rod-like shapes than after 10 deposition cycles. Higher intensity HA peaks were detected after 30 deposition cycles than after 10 deposition cycles. The Ca/P ratio increased with increasing numbers of deposition cycle, and the highest Si percent appeared after 30 deposition cycles. The polarization resistance values commonly decreased more on the nanotube surface formed at 20 V than on the nanotube surface formed at 10 V, and the values also decreased after Si-HA deposition.

Biocompatibility of nanotube formed Ti-30Nb-7Ta alloys

The purpose of this study was to investigate the biocompatibility of Ti-30Nb-7Ta alloy surface decorated with TiO2 nanotubes by anodization in an electrolyte containing 1 M H3PO4 and 0.8 wt.% NaF with an applied voltage of 10 V for 2 h. The anodization was carried out using a scanning potentiostat. The microstructures of alloys and morphology of the nanotubes were investigated by optical microscopy, field emission scanning electron microscopy, and X-ray diffractometry. In comparison to the Ti-30Nb-3Ta alloy, the Ti-30Nb-7Ta alloy contained a lower amount of α" phase, while the β phase was higher. In this study, we observed the formation of a spongy porous layer on the Ti-30Nb-7Ta alloy, while the Ti-30Nb and Ti-30Nb-3Ta alloys showed an absence of such a spongy layer.

Surface morphology of nanotube formed Ti alloy by electrochemical methods

In order to investigate the surface morphology of nanotube formed Ti alloy by electrochemical methods, the Ti-6Al-4V alloys for dental implant were used in this study. Heat treatment was carried out at 800 degrees C for 1 hour and then water quenching in argon atmosphere, that will be have a specimen name of 800 WQ. The formation of nanotube structure was conducted by electrochemical method on Ti-6Al-4V alloy in mixed electrolytes at 30 V for 1 hour. Microstructure of β phases showed dot-like structures at non-treated Ti-6Al-4V alloy, and needle-like in equiaxed structure from treated the alloy at 800 WQ. In non-treated Ti-6Al-4V alloy case, nanotubes only exhibited at α phase region with dissolved V-oxide area of β phase. However, in the case of 800 WQ, nanotubes of Ti-6Al-4V alloy exhibited at both α and βphase region. Electrochemical corrosion studies showed that the nanotubular alloy of 800 WQ possesses slightly higher corrosion resistance than that of non-treated nanotubular alloy.

Electrochemical and sputtering deposition of hydroxyapatite film on nanotubular Ti-25Ta-xZr alloys

The purpose of this study was to investigate the electrochemical and sputtering deposition of hydroxyapatite film on nanotubular Ti-25Ta-xZr alloys. The formation of nanotubular structures was achieved on the alloys by anodization in 1 M H3PO4 electrolyte containing 0.8 wt% NaF at room temperature. Electrochemical deposition was carried out using cyclic voltammetry at 80 degrees C in 5 mM Ca(NO3)2+3 mM NH4H2PO4 solution. Then, physical vapor deposition coating was obtained by radio frequency magnetron sputtering technique. The microstructures, phase transformation, and morphology of the hydroxyapatite film deposited on Ti-25Ta-xZr alloys were analyzed by optical microscopy, X-ray diffraction, and field emission scanning electron microscope. It was found that, as Zr content increased, precipitates of hydroxyapatite changed their leaf-like shape into a needle-like shape. For the alloy with the higher Zr content, the surface of the nanotubes was entirely covered with the radio frequency sputtered HA film. Wettability increased in the following order: bulk, nanotubular surface, and hydroxyapatite-coated nanotubular surface.

Surface characteristics of HA coating and micro-pore formation on the Ti-25Nb-xHf alloys for dental materials

Micro-pore formation on titanium surface can increase the adhesion strength with increment of surface area, and hydroxyapatite is effective coating materials as a main chemical constituent of bone tissue for biomedical field. The aim of this study was to investigate the surface characteristics of HA coating and micro-pore formation on the Ti-25Nb-xHf alloys for dental materials. The Ti-25Nb-xHf alloys consisted of (0 and 7) wt.% Hf contents which were manufactured by vacuum arc-melting furnace. The homogenization was performed at 1000 degrees C for 12 h and water quenched. Anodization was carried out using an electrochemical method in 1 M H3PO4 electrolyte. The HA films were deposited by plasma sputtering method. The microstructures of alloys were transformed from α" phase to β phase by addition of Hf element, and needle-like structures were translated to an equiaxed structure as Hf content increased. The peaks of anatase and rutile showed on the anodized surface of these alloys. The number of micro-pore decreased, with presence of Hf content increased, whereas size of micro-pore increased. Anodized surface was covered with HA particles at surface and in holes. Contact angle value of HA coating on anodized surface was lower than that of non-coating surface.

Hydroxyapatite precipitation on nanotube surfaces of Ti-35Ta-xNb alloys

Hydroxyapatite precipitation on nanotube surfaces of Ti-35Ta-xNb alloys was investigated using electrochemical methods. The alloys were prepared by arc-melting, heat treated at 1050 degrees C for 12 h in an Ar atmosphere, and quenched in 0 degrees C water. Nanotubes were created on the Ti-35Ta-xNb alloys in a 1 M H3PO4 + 1.2 wt.% NaF electrolyte at room temperature. Hydroxyapatite precipitation was carried out in a 0.03 M Ca(NO3)2 x 4H2O + 0.018 M NH4H2PO4 solution at 80 ± 1 degrees C, using 10 deposition cycles. Information about morphology and composition was obtained by FE-SEM and EDS. The microstructure of the Ti-35Ta-xNb alloys was transformed from α phase to βphase as the Nb content increased. The HA precipitates had a plate-like morphology on bulk Ti-35Ta-xNb alloys and a flower-like morphology on nanotubular Ti-35Ta-xNb alloys.

Nanotube nucleation phenomena on Ti-25Ta-xZr alloys for implants using ATO technique

The purpose of this study was to investigate nanotube nucleation phenomena on the Ti-25Ta-xZr alloys for implant materials, using an anodic titanium oxide (ATO) technique. Ti-25Ta-(0 wt.%-15 wt.%) Zr alloys were prepared using a vacuum arc-melting furnace. The Ti-25Ta-xZr alloys were then homogenized for 12 hr at 1000 degrees C, followed by water quenching. Formation of the nanotubular oxide surface structure was achieved initially on the Ti-25Ta-xZr alloys by anodization in a 1 M H3PO4 electrolyte containing 0.8 wt.% NaF at room temperature, using a potentiostat. After the first formation of the nanotubes was achieved, this initial nanotube layer was eliminated, and further anodization was carried out repeatedly. The microstructure, phase transformation, and morphology of nanotubular Ti-25Ta-xZr alloys and the process of nanotube growth using this ATO method were analyzed by X-ray diffraction, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. Microstructures of the Ti-25Ta-xZr alloys changed from α" phase to β phase. Nanotubes formed with the ATO technique had pit-like top holes, with thinner walls and lower contact angle, compared to the initially formed nanotubes.

Effect of various intraoral repair systems on the shear bond strength of composite resin to zirconia

PURPOSE

This study compared the effect of three intraoral repair systems on the bond strength between composite resin and zirconia core.

MATERIALS AND METHODS

Thirty zirconia specimens were divided into three groups according to the repair method: Group I- CoJet™ Repair System (3M ESPE) [chairside silica coating with 30 µm SiO₂ + silanization + adhesive]; Group II- Ceramic Repair System (Ivoclar Vivadent) [etching with 37% phosphoric acid + Zirconia primer + adhesive]; Group III- Signum Zirconia Bond (Heraus) [Signum Zirconia Bond I + Signum Zirconia Bond II]. Composite resin was polymerized on each conditioned specimen. The shear bond strength was tested using a universal testing machine, and fracture sites were examined with FE-SEM. Surface morphology and wettability after surface treatments were examined additionally. The data of bond strengths were statistically analyzed with one-way ANOVA and Tamhane post hoc test (α=.05).

RESULTS

Increased surface roughness and the highest wettability value were observed in the CoJet sand treated specimens. The specimens treated with 37% phosphoric acid and Signum Zirconia Bond I did not show any improvement of surface irregularity, and the lowest wettability value were found in 37% phosphoric acid treated specimens. There was no significant difference in the bond strengths between Group I (7.80 ± 0.76 MPa) and III (8.98 ± 1.39 MPa). Group II (3.21 ± 0.78 MPa) showed a significant difference from other groups (P<.05).

CONCLUSION

The use of Intraoral silica coating system and the application of Signum Zirconia Bond are effective for increasing the bond strength of composite resin to zirconia.

Surface observation of nanotube/micropit formed Ti-Nb-xZr alloy for biocompatibility

To improve bone tissue integration on implant surfaces, nanotube formation and laser texturing techniques have been used to increase the roughness of the implant surfaces. In this study, surface film of nanotube/micropit formed Ti-3ONb-xZr and Ti-30Ta-xZr alloy with low elastic modulus have been investigated using field emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscope (EDS). The alloying elements can play role in controlling the nanotube shape and micropit shape, the highly ordered nanostructure, and contact angle for biocompatibility.

Surface morphology of highly ordered nanotube formed and laser textured beta titanium alloys

The aim of the present study is to produce and characterize a well-controlled surface texture on Ti-35Nb-xHf alloys to promote osseointegration. Ti-35Nb-xHf (x = 0, 3, 7 and 15 wt.%) alloys were prepared by arc melting and heat treated for 12 hr at 1000 degrees C in an argon atmosphere and then water quenching. For surface texturing, an amplified Ti: sapphire laser system was used for generating 184 femtosecond (FS, 10(-15) sec) laser pulses with the pulse energy over 30 mJ at a 1 kHz repetition rate with a central wavelength of 800 nm. The nanotube formation was achieved by anodizing a Ti-35Nb-xHf alloy in H3PO4 electrolytes containing 0.8 wt.% NaF at room temperature. The surface morphology of nano/micro structure will enhance osseointegration and cell adhesion.

Surface phenomena of hydroxyapatite film on the nanopore formed Ti-29Nb-xZr alloy by anodization for bioimplants

In this study, surface phenomena of hydroxyapatite (HA) film on the nanopore formed Ti-29Nb-xZr alloy by anodization for bioimplants have been investigated by electron beam physical vapor deposition (EB-PVD), field emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), potentiostat and contact angle. The microstructure of Ti-29Nb-xZr alloys exhibited equiaxed structure and alpha" phase decreased, whereas beta phase increased as Zr content increased. The increment of Zr contents in HA coated nanotubular Ti-29Nb-xZr alloys showed good corrosion potential in 0.9% NaCI solution. The wettability of HA coated nanotubular surface was higher than that of non-coated samples.

Formation of nano-phase hydroxyapatite film on TiO2 nano-network

Nano- and micro-phase HA film formed on TiO2 nano-network surface by simple electrochemical treatment. The range of lateral pore size of the network specimen was about 10-120 nm on Ti surface by anodized in 5 M NaOH solution at 0.3 A for 10 min. Nano-network TiO2 surface were formed by this anodization step which acted as templates and anchorage for growth of the HA during subsequent pulsed electrochemical deposition process at 85 degrees C. The phase and morphologies of deposits HA were influenced by the electrolyte concentration. The nano needle-like precipitates formed under low SBF concentration were identified to be HA crystals orientated parallel to the c-axis direction. Increasing electrolyte concentration, needle-like deposits transferred to the plate-like and micro plate like precipitates in the case of high SBF concentration.

Effect of coating on properties of esthetic orthodontic nickel-titanium wires

OBJECTIVE

To determine the effect of coating on the properties of two esthetic orthodontic nickel-titanium wires.

MATERIALS AND METHODS

Woowa (polymer coating; Dany Harvest) and BioForce High Aesthetic Archwire (metal coating; Dentsply GAC) with cross-section dimensions of 0.016 × 0.022 inches were selected. Noncoated posterior regions of the anterior-coated Woowa and uncoated Sentalloy were used for comparison. Nominal coating compositions were determined by x-ray fluorescence (JSX-3200, JOEL). Cross-sectioned and external surfaces were observed with a scanning electron microscope (SEM; SSX-550, Shimadzu) and an atomic force microscope (SPM-9500J2, Shimadzu). A three-point bending test (12-mm span) was carried out using a universal testing machine (EZ Test, Shimadzu). Hardness and elastic modulus of external and cross-sectioned surfaces were obtained by nanoindentation (ENT-1100a, Elionix; n  =  10).

RESULTS

Coatings on Woowa and BioForce High Aesthetic Archwire contained 41% silver and 14% gold, respectively. The coating thickness on Woowa was approximately 10 µm, and the coating thickness on BioForce High Aesthetic Archwire was much smaller. The surfaces of both coated wires were rougher than the noncoated wires. Woowa showed a higher mean unloading force than the noncoated Woowa, although BioForce High Aesthetic Archwire showed a lower mean unloading force than Sentalloy. While cross-sectional surfaces of all wires had similar hardness and elastic modulus, values for the external surface of Woowa were smaller than for the other wires.

CONCLUSIONS

The coating processes for Woowa and BioForce High Aesthetic Archwire influence bending behavior and surface morphology.

Nanotubular oxide surface and layer formed on the Ti-35Ta-xZr alloys for biomaterials

Titanium and its alloys are widely used as a dental implant material in clinical dentistry and as an orthopedic implant materials due to their good mechanical properties, corrosion resistance, and biocompatibility. In this study, nanotubular oxide surface and layer formed on the Ti-35Ta-xZr alloys for biomaterials have been investigated by using electrochemical methods. Ti-35Ta-xZr alloys were prepared by arc melting and heat treated for 24 hr at 1000 degrees C in argon atmosphere, and then water quenching. Ti oxide nanotubes were formed on the Ti-35Ta-xZr alloys by anodizing in H3PO4 containing 0.8 wt% NaF solution at 25 degrees C. Anodization was carried out using a scanning potentiostat. Microstructures of the alloys and nanotube surface were examined by FE-SEM, EDX, and XRD. Crystallization treatment of nanotube surface was carried out for 3 hr at 450 degrees C. Microstructures of the Ti-35Ta-xZr alloys were changed from beta phase to alpha'' phase, and changed from an equiaxed to a needle-like structure with increasing Zr content. Nanotubular oxide surface and layers consisting of highly ordered nanotubes with a wide range of diameters (approximately 150-200 nm) and lengths (approximately 4-10 microm) can be formed on alloys in the Ti-35Ta-xZr alloys with Zr content. As the Zr content increased from 3% to 15%, length of step between the bamboo knob-like had increasing values of approximately 50 nm, 80 nm, and 140 nm, respectively. The nanotubes formed on the Ti-35Ta-xZr alloy surface were amorphous structure before heat treatment, but oxide surface had mainly an anatase structure by heat treatment.