Titanium Molybdenum Research Articles

Corrosion resistance of stainless steel, nickel-titanium, titanium molybdenum alloy, and ion-implanted titanium molybdenum alloy archwires in acidic fluoride-containing artificial saliva: An in vitro study.

Objective:(1) To evaluate the corrosion resistance of four different orthodontic archwires and to determine the effect of 0.5% NaF (simulating high fluoride-containing toothpaste of about 2250 ppm) on corrosion resistance of these archwires. (2) To assess whether surface roughness (Ra) is the primary factor influencing the corrosion resistance of these archwires.Materials and Methods:Four different archwires (stainless steel [SS], nickel-titanium [NiTi], titanium molybdenum alloy [TMA], and ion-implanted TMA) were considered for this study. Surface characteristics were analyzed using scanning electron microscopy, atomic force microscopy (AFM), and energy dispersive spectroscopy. Linear polarization test, a fast electrochemical technique, was used to evaluate the corrosion resistance, in terms of polarization resistance of four different archwires in artificial saliva with NaF concentrations of 0% and 0.5%. Statistical analysis was performed by one-way analysis of variance.Results:The potentiostatic study reveals that the corrosion resistance of low-friction TMA (L-TMA) > TMA > NiTi > SS. AFM analysis showed the surface Ra of TMA > NiTi > L-TMA > SS. This indicates that the chemical composition of the wire is the primary influential factor to have high corrosion resistance and surface Ra is only secondary. The corrosion resistance of all wires had reduced significantly in 0.5% acidic fluoride-containing artificial saliva due to formation of fluoride complex compound.Conclusion:The presence of 0.5% NaF in artificial saliva was detrimental to the corrosion resistance of the orthodontic archwires. Therefore, complete removal of residual high-fluorinated toothpastes from the crevice between archwire and bracket during tooth brushing is mandatory.

Microscopic study of surface roughness of four orthodontic arch wires

Aim/purpose Comparative evaluation of surface roughness of stainless steel (SS), nitinol (NiTi), titanium molybdenum alloy (TMA) and copper nitinol (Cu NiTi) orthodontic arch wires before and after clinical use to find the smoothest wire surface best used in orthodontic sliding mechanics. Materials and methods Surface roughness of 40 arch wires divided into four groups (group 1: 10 SS arch wires, group 2: 10 NiTi arch wires, group 3: 10 TMA arch wires and group 4: 10 Cu NiTi arch wires) were measured at five different points for each wire before and after its clinical use in oral cavity for 4 weeks using atomic force microscope and optical digital microscope. All obtained data was statistically tested. Results SS arch wires had the smoothest surface (average roughness: 17.38 μm for new wires and 104.1 μm for used wires) and Cu NiTi arch wires had the roughest surface (average roughness: 221.12 μm for new wires and 499 μm for used wires) with high significant differences between both groups either new or used arch wires (P < 0.001). High significant difference was found between new and used wires for all groups. NiTi wires had greater surface roughness (average roughness: 211.8 μm for new wires and 313.8 for used wires) than TMA wires (average roughness: 138.5 μm for new wires and 221.2 μm for used wires). Conclusion SS orthodontic arch wires exhibited the least amount of surface roughness and advocated to be used in sliding mechanics to minimize the friction during orthodontic tooth movements.

Beta Titanium-Review

Aim : This article reviews the beta titanium, a new material for orthodontics. Objective:. A beta titanium alloy was evaluated for use in orthodontic appliances. Background : Orthodontic wires made from different alloys now offer alternative sequences of wire usage during all phases of orthodontic treatment. It is now possible to match phases of treatment with orthodontic wires according to the mechanical properties of the wire. On this basis, the selection of orthodontic wire should be based not only on the transverse section of the wire, but also on an understanding of the deactivation characteristics of the wire required for different phases of orthodontic treatment. The beta-titanium (s-Ti) wires are titanium molybdenum alloys, introduced for orthodontic use in 1979 by Goldberg and Burstone. The beta titanium wire has a unique balance of low stiffness, high spring back, formability, and weldability which indicates its use in a wide range of clinical applications. A number of such applications are described. Beta-titanium wires have been utilised in orthodontics because of their favourable characteristics such as low stiffness, excellent formability, and efficient working range for tooth movement. In fact, the only major disadvantage of this wire seems to be its cost. Initially used for springs and loops with segmented arches, s-Ti wires have become popular in all areas of orthodontic treatment. Reason : Mechanical properties and manipulative characteristics are summarised to develop a basis for the selection of the proper alloy for a given clinical situation.

Comparison of spring characteristics of titanium-molybdenum alloy and stainless steel.

BackgroundTitanium-molybdenum alloy (TMA) and stainless steel (SS) wires are commonly used in orthodontics as arch-wires for tooth movement. However, plastic deformation phenomenon in these arch-wires seems to be a major concern among orthodontists. This study aimed to compare the mechanical properties of TMA and SS wires with different dimensions.Material and MethodsSeventy-two wire samples (36 TMA and 36 SS) of three different sizes (19×25, 17×25 and 16×22) were analyzed in vitro, with 12 samples in each group. Various mechanical properties of the wires, including spring-back, bending moment and stiffness were determined using a universal testing machine. Student’s t-test showed statistically significant differences in the mean values of all the groups. In addition, metallographic comparison of SS and TMA wires was conducted under an optical microscope.ResultsThe degree of stiffness of 16×22-sized SS and TMA springs was found to be 12±2 and 5±0.4, respectively, while the bending moment was estimated to be 1927±352 (gm-mm) and 932±16 (gm-mm), respectively; the spring-back index was determined to be 0.61±0.2 and 0.4±.09, respectively (p<0.001). There were no statistically significant differences in spring-back index in larger dimensions of the wires.ConclusionsSystematic analysis indicated that springs made of TMA were superior compared to those made of SS. Although both from economic and functionality viewpoints the use of TMA is suggested, further clinical investigations are recommended. Key words:Bending moment, optical microscope, spring-back, stainless steel, stiffness, titanium‒molybdenum alloy.

Right wire in orthodontics: a review

Quality of orthodontic wire such as stiffness, hardness, resiliency, elasticity and working range are important determinants of the effectivenes of tooth movement. Commonly used types of orthodontic arch wire:1) stainless steel(ss) wire, 2) conventional nickel- titanium (NiTi)alloy wire,3) improved super elastic NiTi- alloy wire( also called low hysteresis(LH)wire), and titanium molybdenum alloy(TMA) wire.

Evaluation of periodontal condition in intruded molars using miniscrews

Introduction: The purpose of this preliminary study was to evaluate the periodontal condition of intruded molars in various phases of treatments. Methods: 30 patients with at least one overerupted upper first molar were selected. Upper molar bands with brackets were cemented. Two miniscrews were placed in the mesiopalatal and mesiobuccal aspect of the aforementioned teeth. A titanium molybdenum alloy (TMA) spring was attached to the head of miniscrew in one end and ligated to the bracket in the other end to reach the predetermined force. Plaque index (PI), probing pocket depth (PPD), keratinized gingiva (KG), The distance between miniscrew (M.S) and gingival level (GL), and bleeding on probing (BOP) were recorded before loading and 1, 2, 3, 4 and 5 months post-loading .Results: All patients completed the study and no complications were reported. Statistically significant intrusion (2.1 ± 0.9 mm) was obtained during active treatment. Inserting miniscrews generally was presented with greater sulcus bleeding, plaque accumulation and plaque formation at follow-up visits. There was a statistically significant increase in PI, PPD and BOP indices. Furthermore, the results showed decrease in KG level and M.S to GL level. Conclusion: Miniscrews can provide a clinical benefit as an absolute anchorage device. However, keeping a good oral hygiene is essential to achieve ideal results, because the presence of miniscrews, as a foreign object in mouth, and intrusion force might be harmful for periodontal tissues

Corrosion by the absorbing solution in vacuum–carbonate sulfur removal

The influence of the salts present in the absorbing solution used for vacuum–carbonate sulfur removal on its corrosional activity is studied. The presence of sodium ferrocyanides in the absorbing solution indicates the solution of iron from the equipment. The most corrosive component is sodium formate. A formate concentration no higher than 30–40 g/dm3 is recommended in the working solution. The influence of the temperature on the corrosional activity of the absorbing solution is studied. The temperature dependence of the corrosion rate is extremal. The best materials for the manufacture of circulating heaters for the absorbing solution are titanium and high-alloy molybdenum steel.

The effect of red wine extract, resveratrol, on the degree and rate of orthodontic tooth movement in guinea pigs

ObjectiveAn animal trial, its protocol approved by the Institutional Animal Care and Use Committee of the U.P. National Institutes of Health (IACUC Protocol No. 2010-008), was employed to investigate the effects of resveratrol on the degree and rate of orthodontic tooth movement in guinea pigs.Materials and MethodsEighteen male adult guinea pigs were randomly allocated into 3 groups: low dose, high dose, and control groups. A 0.016″ titanium molybdenum alloy wire formed into a helical torsion spring with a coil, with the loops cemented onto the maxillary incisors of the animals, served as the orthodontic appliance. Daily oral administration of resveratrol was provided to the low dose (0.047 mg/kg) and high dose (0.47 mg/kg) groups, while water was provided to the control group. Measurements were taken everyday at the interproximal area at the level of the incisal edge using a measuring caliper.ResultsThe results of the ANOVA showed no statistically significant differences in the mean measurements of tooth separation among the three groups from day 2 (P=0.966) to day 8 (P=0.056). However, starting from day 9 (P=0.049) until day 18 (P=0.000), there was a significant difference in the mean tooth separation among the test groups.ConclusionUsing the LSD, it was noted that the low dose and the high dose groups have similar degrees of mean tooth separation, with the control group being significantly different from the two.

Structurally-Phase States of Electroexplosive Composite Coatings of the TiB2−Mo System After Electron-Beam Treatment

Electroexplosive composite coatings of TiB2−Mo system are modified using a high-intensity electron beam. The structure and phase and elemental composition of the surface layer of a Hardox 450 steel subjected to electroexplosive deposition of the composite coating of non-mixing TiB2−Mo system subsequently irradiated by a high-intensity electron beam of submillisecond duration are investigated. Regimes of electron-beam treatment are elucidated that allow dense surface layers with mirror-like glitter possessing submicrocrystalline structure to be obtained based on titanium diboride and molybdenum. Our investigations demonstrate that the electron-beam treatment of the electroexplosive coating in the melting regime leads to the formation of a structurally and concentrationally homogeneous layer.

Usage of Titanium Molybdenum Alloy Wires in Nasal Molding: A Case Report

ABSTRACT The purpose of this case report is to present the nasoalveolar molding treatment (NAM) of an infant with complete unilateral cleft lip using a nasal stent with conventional configuration made of 0.32-inch titanium molybdenum alloy (TMA). An additional nasal stent with the same configuration was constructed of stainless steel wire, and the force application by the same activation was measured. In patients with cleft lip who benefit from NAM therapy but cannot come regularly to the weekly appointments, nasal stents made of TMA may be recommended due to lighter and continuous force application.

Double-Loop Technique Using Titanium Molybdenum Alloy Wire for Fabrication of Nasal Stents in Nasoalveolar Molding Therapy for Cleft Lip and Palate Patients

This article presents a technique for fabricating a modified nasoalveolar molding appliance using 0.032-inch titanium-molybdenum alloy wire for nasal stents incorporating a double loop. The nasal stents are included in the acrylic molding plate at the time the appliance is inserted. The acrylic retention button used in a conventional appliance is replaced by a simple retention hook fabricated using titanium-molybdenum alloy wire. This technique is an effective alternative to a conventional appliance, and it simplifies the appliance-modification process during follow-up visits.

Workability Behavior of Powder Metallurgy Carbide Reinforced Aluminum Composites During Hot Forging

Experimental study was conducted to assess the consequence of titanium carbide (TiC), molybdenum carbide (Mo2C), iron carbide (Fe3C), and tungsten carbide (WC) reinforcements on the composite aluminum compacts. The hot deformation of the carbide reinforce aluminum compacts, Al-2TiC, Al-2WC, Al-2Fe3C, and Al-2Mo2C, with aspect ratios of 0.4 and 0.6, was carried out and the workability behaviors of the same were determined. The effect of carbide reinforcement and preform geometry on the relative density, stress ratio, σθ/σeff, and formability ratio was studied.

Comparison of frictional resistance of esthetic and semi-esthetic self-ligating brackets

Aim:The frictional resistance encountered during sliding mechanics has been well established in the orthodontic literature, and it consists of complex interactions between the bracket, archwire, and method of ligation the claim of reduced friction with self-ligating brackets is often cited as a primary advantage over conventional brackets. This study was done to compare and evaluate the frictional forces generated between fully esthetic brackets and semi-aesthetic self-ligating brackets, which are of passive form and SEM (scanning electron microscope) study of the Brackets after Frictional evaluation.Materials and Methods:Two types of self-ligating esthetic brackets, Damon clear (Ormco) made of fully ceramic and Opal (Ultradent Products, USA) and, Two types of self-ligating semi-esthetic brackets, Clarity SL (3M Unitek) and Damon 3 (Ormco) both of which are made of ceramic with metal slot. Arch wires with different dimensions and quality 17 × 25, 19 × 25 Titanium Molybdenum Alloy (TMA) and 17 × 25, 19 × 25 stainless steel that came from plain strands of wire were used for frictional comparison test. The brackets used in this study had 0.022 × 0.028 inch slot.Results:The statistical tests showed significantly smaller amount of kinetic frictional forces is generated by Damon 3 (semi-esthetic self-ligating brackets). For each wire used, Damon 3 displayed significantly lower frictional forces (P ≤ 0.05) than any of the self-ligating system, followed by Opal (fully esthetic self-ligating brackets) which generated smaller amount of frictional forces but relatively on the higher side when compared with Damon 3. Damon clear (fully esthetic self-ligating brackets) generated the maximum amount of kinetic forces with all types of wire dimensions and properties when compared to the other three types of self-ligating system. Clarity SL (semi-esthetic self-ligating brackets) generated smaller amount of frictional forces when compared with Damon clear and relatively higher amount of frictional forces when compared to Opal and Damon 3

Periodontal changes following molar intrusion with miniscrews.

Background:With the introduction of skeletal anchorage system, recently it is possible to successfully intrude molar teeth. On the other hand, there have been concerns about periodontal changes associated with intrusion and there are few studies on this topic, especially for posterior teeth.Materials and Methods:Ten female patients were enrolled in this study. Maxillary molar intrusion was achieved by inserting two miniscrews and a 17 × 25 titanium molybdenum alloy spring. Crestal height changes were evaluated at three intervals including: Baseline (T0), end of active treatment (T1) and 6 months after retention (T2). Other variables including probing depth, gingival recession, attachment level and bleeding on probing were evaluated by clinical measurements in the three above mentioned intervals. One-sample Kolmogrov-Smirnov test ascertained the normality of the data. For all patients, the changes in tooth position and crestal height were evaluated using one-sample t-test. (P < 0.05)Results:Supra-erupted molars were successfully intruded a mean of 2.1 ± 0.9 mm during active treatment (T0-T1). A mean bone resorption of 0.9 ± 0.9 mm in mesial crest and 1 ± 0.8 mm in distal crest had occurred in total treatment (T0-T2). A mean of 0.6 ± 1.4 mm bone was deposited on mesial crest during the retention period (T1-T2) following tooth relapse. On average, 0.8 ± 0.4 mm attachment gain was obtained. Gingival margin coronalized a mean of 0.8 ± 0.6 mm throughout the entire treatment. Probing depth showed no significant change during treatment.Conclusion:Within the limitations of this study, these results suggest that not only periodontal status was not negatively affected by intrusion, but also there were signs of periodontal improvement including attachment gain and shortening of clinical crown height.

Workability studies of sintered aluminium composites during hot deformation

Experimental investigation has been carried out to evaluate the effect of titanium carbide (TiC), molybdenum carbide (Mo2C), iron carbide (Fe3C) and tungsten carbide (WC) addition on the composite aluminium preforms. The hot upsetting of the composite aluminium preforms with various carbide contents, namely, Al-4% TiC, Al-4% WC, Al-4% Fe3C and Al-4% Mo2C, and different aspect ratios, namely, 0.4 and 0.6, was carried out and the workability behaviour of the same was determined. The influence of carbide addition in the aluminium composite and initial preform geometry on the relative density ( R), stress ratio parameters, [Formula: see text], [Formula: see text] and [Formula: see text], and formability stress index was studied.

Vacancy-mediated ω-assisted α-phase formation mechanism in titanium–molybdenum alloy

This study investigates the mechanism of the ω-to-α phase transformation in a titanium–molybdenum alloy. Using aberration-corrected high annular angle dark-field scanning transmission electron microscopy and density functional theory (DFT), the authors demonstrate that the ω-to-α phase transformation is mediated by vacancy ordering. Atomic resolution Z-contrast images display high- and low-contrast regions in a single ω precipitate, and it was found that the low Z-contrast regions are composed of an unknown structure, which differs significantly from the ω-phase crystal structure. DFT calculations show that the vacancies could be stabilized by Mo and should preferably be assembled with ordering. The relaxed ω-phase structure with ordered defects explains the intricate atomic images in the low Z-contrast regions of the ω phase. It was found that this distorted ω phase with defects is similar to the hexagonal α-phase structure with vacancies. It was confirmed that these vacancies could easily be occupied by Ti atoms and could form a perfect α phase.

Increasing Pt methanol oxidation reaction activity and durability with a titanium molybdenum nitride catalyst support

Titanium molybdenum nitride (Ti0.8Mo0.2N) hybrid support is prepared by a facile and efficient method, including a one-pot solvothermal process followed by a thermal treatment under ammonia at 750 °C, and this hybrid support is further decorated with Pt nanoparticles to catalyze the oxidation of methanol. The catalyst is characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. XRD and TEM results show that the synthesized Ti0.8Mo0.2N is formed as a single-phase solid solution with high purity. Notable, Ti0.8Mo0.2N supported Pt catalyst exhibits a much higher mass activity and durability than that of the conventional Pt/C (E-TEK) electrocatalysts for methanol electrooxidation. The experimental data indicates that the Mo doping has the bifunctional effect that improves the performance and durability of the supported Pt NPs by inducing both co-catalytic and electronic effects.

Structure and properties of arc evaporated nanoscale TiN/MoN multilayered systems

Using vacuum-arc evaporation method we fabricated periodic multilayered TiN/MoN structures with different bilayer periods λ ranging from 25 to 100nm. Rutherford backscattering (RBS), X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM) and microhardness measurements were used for investigations of composition, structure and mechanical properties of the multilayered coatings. We found that molybdenum nitride and titanium nitride layers grown on steel show local partial epitaxy and columnar growth across interfaces. A molybdenum–titanium carbide interlayer was evidenced between the substrate and the multilayer. Molybdenum nitride and titanium nitride layers contain small (5–30nm) grains and are well crystallized with (100) preferred orientation. They were identified as stoichiometric fcc TiN and cubic γ-Mo2N. Non-cubic molybdenum nitride phases were also detected. The hardness of the obtained structures achieved great values and maximal hardness was 29–31GPa for multilayered structure with 50nm period. Hardness of the obtained coatings is 25% higher in comparison with initial single-layer nitride coatings, wherein plasticity index (H/E) of multilayered structure is 0.075.

Finishing effectiveness of different archwires using SmartClip™ self-ligating brackets: A clinical study

The aim of this clinical prospective trial was to evaluate finishing effectiveness of stainless steel (SS) archwires versus titanium molybdenum alloy (TMA) archwires using SmartClip™ self-ligating brackets. Thirty-two patients were divided in two groups: a group of 21 (G1-SS) and a group of 12 (G2-TMA). The protocol consisted of two different finishing archwires coupled with self-ligating brackets: .019 × .025" SS archwires for G1-SS and .019 × .025" TMA archwires for G2-TMA. Lateral cephalometric radiographs obtained at the beginning (T1) and end (T2) of treatment were used to assess the changes in incisor inclination, and measurements of irregularity index (LII), interdental widths, arch length (AL) and arch depth (AD) were made on dental casts to investigate changes associated with crowding correction. No significant differences from T1 to T2 were found for incisors proclination and AL changes. Statistically significant differences were found for LII (higher decrease in G1-SS), maxillary AD (higher increase in G1-SS) and three interdental maxillary widths (higher in G1-SS). The statistically significant differences found were few and clinically negligible. Self-ligating brackets system coupled with .019 × .025" archwires showed good finishing effectiveness, but no clinically significant differences were found between SS and TMA.

Microscopic Grain Structure Analysis of Titanium-based Orthodontic Archwires

Introduction: Orthodontic archwires are designed to move teeth with light continuous forces. Great strides have been accomplished and are continuously evolving to produce the ‘perfect’ wire through complete knowledge of their metallurgical properties. Advent of shape memory alloys in orthodontics has been phenomenal. This study addresses the need of basic understanding of its micrograin structure. Materials and methods: Nickel-titanium and titanium molybdenum; archwires were selected. Each of the samples was studied using following equipments: Scanning electron microscopy and energy dispersive X-ray spectroscopy. Results: Surface topography of nickel-titanium alloys showed a highly rough surface with pits along with phases of intermetallic compounds of TiNi, Ni4Ti and Ti2Ni while titanium molybdenum alloys showed a highly porous surface topography. Precipitates of stabilizing elements were seen at the grain boundaries in both the alloys. Nickel-titanium alloys showed equiatomic concentrations of nickel and titanium with titanium to be slightly more than nickel. High percentage of interstitial elements like carbon, oxygen, etc. were detected; while titanium molybdenum showed maximum percentage of titanium followed by beta stabilizer, molybdenum and low concentrations of interstitial elements. Conclusion: Metallurgists are continuously experimenting with alloying elements to improve titanium alloys with consistent and predictable properties.