Titanium Bars Research Articles

Microstructural characterization and hardness properties of electric resistance welding titanium joints for dental applications.

The electric resistance welding procedure is used to join a titanium bar with specific implant abutments in order to produce a framework directly in the oral cavity of the patient. This investigation studied the effects of the welding process on microstructure and hardness properties of commercially pure (CP2 and CP4) Ti components. Different welding powers and cooling procedures were applied to bars and abutments, normally used to produce the framework, in order to simulate the clinical intraoral welding procedure. The analyses highlighted that the joining process did not induce appreciable changes in the geometry of the abutments. However, because of unavoidable microstructural modifications in the welded zones, the hardness decreased to values lower than those of the unwelded CP2 and CP4 Ti grades, irrespective of the welding environments and parameters.

Recovery and Recrystallization Behavior of Large Sized β Phase Grains in TC18 Titanium Alloy during Annealing Process

The manufacturing processes of TC18 titanium alloy bar takes about 10 times forging. During forging, the β phase grain experiences a series complicated process such as recovery, recrystallization and grain growth. Larger sized β phase grains can easily be formed under different conditions such as insufficient deformation or slow cooling rate during the forging process, which may affect the mechanical properties of TC18 bars. In order to find out the causes and elimination methods of large β grains, this paper used EBSD techniques to analyze the microstructure and texture of TC18 titanium bar at center layer, 1/2R layer and surface layer after the process of forging and heat treatment. Results show that a large portion of β grains experiences recovery and grain growth, while a minor portion of β grains only experiences recrystallization after α+β region heat treatment. Most β grains experience recrystallization, while for those β grains which are hard to be swallowed by recrystallized grains only experience recovery after β region heat treatment. Rather than eliminate the large sized β grains, it’s even easier for those β grains to grow up during annealing process under the condition of insufficient deformation.

Research on Stable Forming of Titanium Alloy Bar Using Three-Roll Skew Rolling

Titanium alloy with high strength, corrosion resistance, heat resistance and many other advantages has widely applications in aviation industry and the military-industrial complex. The market demand for titanium alloy increases year by year. However, the rolling technology for small size titanium rod is not mature due to its poor plasticity and difficult processing. In addition, current titanium alloy bar can not meet the high-end market requirements, it still largely dependents on imports now. Developing high-quality titanium bars is a major aim of titanium industry in our country in the future. Three-roll rolling is one of mature methods in current production of titanium alloy bars. Using this processing method for rolling titanium alloy bars, multi-standard, low-volume production requirements can be achieved.

Modified protocol of the intraoral welding technique for immediate implant-supported rehabilitation of the edentulous maxilla.

The aim of this study was to report the outcomes of a treatment option of immediate loading with intraoral welding on only 4 implants for the restoration of patients with maxillary edentulism. Seventeen consecutive patients were rehabilitated with 2 parallel and 2 tilted implants in the maxilla. Immediately after implant placement, angulated abutments were screwed on the implants to create better parallelism among the implants; thereafter, a titanium bar was intraorally welded to the welding pins to create a superstructure that rigidly splinted the implants. A fixed full-arch durable prosthesis was delivered on the same day of the surgery. The patients were followed for 26.5 months on average. During the follow-up time, 2 implants were lost giving an implant survival rate of 97%. Nonetheless, all the prostheses remained in function and the prosthetic success was 100%. The rehabilitation of the edentulous maxilla with an immediately loaded full-arch prosthesis, obtained through intraoral welding on only 4 implants, is a functionally and esthetically successful treatment.

The effect of initial grain size on the mechanical properties and deformability of titanium alloy in a direct extrusion process

This study determines the effect of grain size on the mechanical properties and the deformability of titanium bar in a direct extrusion process. The specimen of commercially pure grade 2 (CP2) with a diameter of 5 mm is annealed at various temperatures, to obtain different grain sizes, and extruded with die angles of 5, 10 and 15°. The results show that the initial grain size of α-phase microstructure is in the range of 59.7 to 122.1. The strength coefficient, yielding stress and hardness of the annealed specimen with an α-phase microstructure decreases as the grain size increases. β-phase microstructure forms when the annealing temperature exceeds 800°C, which leads to a reduction in the ductility and extrusion deformability, but an increase in the hardness. The grain evolution sequences are coarse columnar, thin columnar and refined grain. The initial grain size has no significant effect on extrusion force. The hardness of the refined grains is close to that of the initial grains.

The influence of saliva pH value on the retention and durability of bar-clip attachments.

PURPOSEThe aim of this study was to compare the durability and retention of 4 types of attachments placed over computer aided design/computer aided manufacturing (CAD/CAM) titanium bars when subjected to different pH conditions.MATERIALS AND METHODSFour commercially available attachments were investigated: Hader Yellow, Hader Red, Ackerman Gold and Ackerman Stainless Steel. These attachments and Ackerman CAD/CAM titanium bars were placed in 2 vessels containing different artificial saliva solutions (pH 7/pH 4) at 37℃ for one month to simulate corrosion conditions, and they were then subjected to mechanical testing (5400 cycles of insertion and removal).RESULTSThe results revealed that there were significant differences in the average values of insertion/removal force due to the pH (F (1, 24)=9.207, P<.05) and the type of attachment (F (3, 24)=11.742, P<.05).CONCLUSIONMore acidic pH values were found to have a negative influence on the retention capacity of the attachments.

Plasmocitoma de esternón: reconstrucción esternal con malla biológica y barras de titanio. Reporte de caso

Un paciente con enfermedad neoplasica que compromete la pared toracica es tratado con reseccion quirurgica primaria con buenos resultados a largo plazo. Se presenta un caso de un hombre de 55 anos con un plasmocitoma esternal, tratado con reseccion quirurgica de la lesion, requiriendo reconstruccion de la pared toracica con malla biologica de dermis de cerdo y barras de titanio. Aun no hay estudios que documenten un consenso de cual debe ser el tratamiento de eleccion para el plasmocitoma oseo solitario: cirugia o radioterapia. Cualquiera de estos tratamientos, unicos o combinados, son validos. Para la reconstruccion posterior a la reseccion, los abordajes realizados con materiales novedosos y anatomicamente correctos garantizan una tecnica apropiada, minimizando las complicaciones y garantizando una adecuada calidad de vida

Recent and Future Developments in Chest Wall Reconstruction

Reconstruction following major chest wall resection can be challenging. Conventional methods of using mesh with or without incorporation of methyl methacrylate are slowly being replaced by chest wall reconstruction prosthetic systems that use titanium plates or bars. The most popular systems in use are the titanium STRATOS bars and MatrixRIB plates, which have different systems for securing to the chest wall. In general, these new approaches are user friendly, are more ergonomic, and may avoid certain complications associated with the more conventional methods of reconstruction. However, the successful implantation of these titanium prosthetic systems requires the operator to be familiar with the limitations and potential pitfalls of the process. Follow-up data are only just emerging on the risk factors for implant failure of these prosthetic systems, as well as certain device-specific complications, with fracture failure being increasingly recognized as a significant problem. In the future, emerging intraoperative real-time imaging and 3-dimensional printing technology, as well as development in biomaterials, will allow chest wall reconstruction to become increasingly personalized.

Effect of Bonding Agent Application Method on Titanium-Ceramic Bond Strength.

Although milled titanium may be used as a substructure in fixed and implant prosthodontics, the application of the veneering porcelain presents particular challenges compared to traditional alloys. To address these challenges, some Ti ceramic systems incorporate the application of a bonding agent prior to the opaque layer. Vita Titankeramik's bonding agent is available as a powder, paste, and spray-on formulation. We examined the effect of these three application methods on the bond strength. Four titanium bars were milled from each of 11 wafers cut from grade II Ti using the Kavo Everest milling unit and a custom-designed milling toolpath. An experienced technician prepared the 25 × 3 × 0.5 mm(3) metal bars and applied bonding agent using one of three application methods, and then applied opaque, dentin, and enamel porcelains according to manufacturer's instructions to a 8 × 3 × 1 mm(3) porcelain. A control group received no bonding agent prior to porcelain application. The four groups (n = 11) were blindly tested for differences in bond strength using a universal testing machine in a three-point bend test configuration, based on ISO 9693-1:2012. The average (SD) bond strengths for the control, powder, paste, and spray-on groups, respectively, were: 24.8 (2.6), 24.6 (2.6), 25.3 (4.0), and 24.1 (3.9) MPa. One-way ANOVA and Tukey's multiple comparison tests were performed between all groups. There were no statistically significant differences among groups (p = 0.951). Titanium-porcelain bond strength was not affected by the use of a bonding agent or its application method when tested by ISO 9693-1 standard.

Experimental Study of Bond Strength between Titanium Bar and Lime-Based Mortar

AbstractIn the last decades, a number of technical solutions for the improvement of structural connections using new materials between masonry wall panels have been the subject of several studies. In this context, the increasing interest in titanium could be attributed to its high specific resistances and chemical stability. The emphasis of this study is therefore the understanding of the bond behavior between lime-based mortars and titanium-based reinforcing rods. Experimental results showed that the titanium-lime bond is characterized by low bond strength. With the aim of increasing bond stresses, different surface treatments were investigated based on chemical and mechanical interlocking. The effect of these treatments and the general problems related to masonry reinforcing techniques have been discussed.

Grain Size Effect on Mechanical Properties of Titanium Alloy

The aim of this study is to investigate the effect of grain size on mechanical properties of commercially pure grade 2 (CP2) titanium bar with a diameter of 5 mm. The results reveal that the microstructure of β-phase forms when the annealing temperature exceeds 800oC. The formation of β-phase leads to reduce the ductility but increase hardness. The strength coefficient, yielding stress and hardness decrease with increasing of grain size when the microstructure of specimen is the α-phase.

Effect of intermediate ZrO2-CaO coatings deposited by cold thermal spraying on the titanium-porcelain bond in dental restorations

Metal ceramic systems are used for the majority of dental crowns and fixed dental prostheses. However, problems with porcelain bonding are encountered when titanium is used as the substrate. The purpose of this study was to evaluate the effect of intermediate calcium oxide-stabilized zirconia (ZrO2-CaO) coatings deposited by cold thermal spraying on the titanium-porcelain bonding in dental restorations. Two different types of ZrO2-CaO coatings obtained by oxyacetylene cold thermal spraying deposition were applied on commercially pure titanium bars before adding the porcelain layer. Type 1 was obtained by directly spraying the ZrO2-CaO powder on the titanium substrate. Type 2 was obtained by spraying a bond coat of nickel-aluminum-molybdenum alloy before spraying the ZrO2-CaO powder. Three-point bend tests according to International Organization of Standardization 9693-1:2012 were carried out to evaluate the debonding strength for the ZrO2-CaO-coated specimens (types 1 and 2) in comparison with a noncoated group (control), which received a traditional bonder-based adhesive technique. The results were compared with ANOVA, followed by the Student-Newman-Keuls test for pairwise comparisons. Scanning electron microscopy and energy dispersion spectroscopy were used to examine the interfacial properties and the failure mode of eachgroup. Mean (±standard deviation) debonding strength values for type 1 coating (25.97 ±2.53 MPa) and control (23.51±2.94 MPa) were near the acceptable lower limit of 25 MPa indicated by the International Organization of Standardization 9693-1:2012 and were not significantly different (Student-Newman-Keuls test, P>.05). Type 2 coating produced an improved titanium-porcelain bonding (debonding strength=39.47 ±4.12 MPa), significantly higher than both type 1 (Student-Newman-Keuls test, P<.05) and control (Student-Newman-Keuls test, P<.05). Scanning electron microscopy-energy dispersion spectroscopy analysis confirmed these findings, which revealed a predominant cohesive failure mode for type2. An intermediate coating layer of ZrO2-CaO plus a substrate of bonding nickel-aluminum-molybdenum alloyapplied by oxyacetylene cold thermal spraying deposition provided an improved titanium-porcelain bond.

Posterior alveolar ridge resorption in bar‐retained mandibular overdentures: 10‐year results of a prospective clinical trial

Data on posterior alveolar ridge resorption (PARR) in patients with two implant supported mandibular overdentures is very heterogeneous. The aim of this prospective study was to observe the PARR after ten years for a study population treated with a titanium bar retained overdenture on two IMZ-implants. The data pool consisted of digital and digitized conventional panoramic radiographs taken prior to implant placement and at follow up appointments. Digital measurements were carried out following an established procedure ("Tuebingen method" by Gomez-Roman). For each patient a linear regression was calculated resulting in a relative area related PARR-value per year. A simplified geometrical scenario was used for the estimation of absolute bone height losses. Data of 23 patients was available. The mean observation period was 9.4years (±2.4years). An average area related PARR-rate of 1.02% per year was observed with high individual differences ranging from 0.15% and 2.63% per year. The estimated average ten year vertical bone loss in the chewing center was 1.5mm. Posterior bone resorption was found to be in the range previously reported for different implant restorations and therefore does not represent a particular problem of two implant bar retained overdentures. The results strengthen the two implant concept.

The Bone Conduction Implant—First Implantation, Surgical and Audiologic Aspects

To report on preoperative assessment, surgery, and audiologic outcome of the first patient implanted with the bone conduction implant (BCI). The BCI is a bone conduction hearing device with an intact skin solution where the transducer is implanted close to the ear canal opening. By avoiding a percutaneous screw attachment to the skull, the BCI is anticipated to reduce complications associated with the Bone-Anchored Hearing Aid (BAHA) solution. The first patient to receive a BCI was a 42-year-old woman with a unilateral mixed hearing loss due to tympanosclerosis. Preoperative and postoperative cone beam computed tomography and a virtual planning tool for 3D reconstruction were used to optimize and control the position of the BCI in the mastoid. The transducer was placed in a 5-mm deep seating in the mastoid and secured with a titanium bar. Free field tone and speech audiometry were conducted to evaluate the audiologic outcome at baseline (1 month postoperatively) and 1 month after baseline. The BCI was placed in the position according to the preoperative 3D planning. On average, the tone thresholds improved by 30 dB, speech reception thresholds by 25.5 dB and speech signal-to-noise ratio by 9.7 dB. The surgical procedure was considered simple and safe. The BCI can be implanted by a safe and easy surgical procedure. 3D preoperative planning can be helpful to optimize the BCI position. The BCI is a realistic alternative to the BAHA.

CAD/CAM으로 제작된 milled titanium bar와 Locator®를 이용한 상악 임플란트 유지 피개의치: 증례보고

본 증례는 상악 무치악 환자에서 임플란트 피개의치 제작시 CAD/CAM으로 제작된 milled titanium bar에 Locator<TEX>$^{(R)}$</TEX>를 장착한 바 어태치먼트 시스템을 사용한 증례이다. 2년 이상 경과 후, 기능과 심미적인 면에서 만족할 만한 성과를 얻었다. The purpose of this case report is to introduce milled titanium bar with Locator<TEX>$^{(R)}$</TEX> that made by CAD/CAM for implant supported overdenture in maxillary edentulous patients. For over 2 years, in terms of function and esthetics, satisfactory result was obtained.

Primary chest wall chondrosarcomas: results of surgical resection and analysis of prognostic factors

Wide surgical excision with tumour-free margins is the mainstay of therapy for primary chest wall chondrosarcoma (PCWC). Few studies on treatment outcome and prognostic factors of PCWC requiring chest wall resection are available. We analysed our experience on surgical treatment of PCWC with emphasis on survival and recurrence prognostic factors. From 1986 to 2012, 89 patients (65.2% males, median age 55 years) with PCWC were operated on. The median tumour maximum diameter was 7 cm (range 2-30 cm). We performed 23 sternectomies and 66 lateral chest wall resections (median ribs resected: 2; range 1-7). Resections were extended to lung (n = 19), diaphragm (n = 13), vertebral body (n = 6) or clavicle (n = 1). Negative margins were obtained in 85.4% of cases. Chest wall reconstruction was obtained mainly by prosthetic non-rigid or rigid materials and muscle flap coverage. In the last years, 3 patients received a sternal replacement with cadaveric allograft, and 2 had a chest wall reconstruction with titanium bars and 17 with a rib-like prosthesis. Perioperative mortality and morbidity rates were 0 and 12.4%, and 5- and 10-year overall and disease-free (on R0 resections) survival rates were 67.1 and 57.8%, and 70 and 52%, respectively. A favourable outcome (univariate analysis) was seen for G1 tumours (P < 0.0001), negative surgical margins (P < 0.0001), age ≤55 years (P = 0.005), no adjuvant treatment (P < 0.001) and diameter ≤6 cm (P = 0.005). Independent predictors of better survival (multivariate analysis) were negative surgical margins (P = 0.0001), G1 tumours (P = 0.02), age ≤55 years (P = 0.006) and diameter ≤6 cm (P = 0.006). A predictive risk factor for recurrence was histological grade. Surgical resection of PCWC leads to good oncological outcome. Wide surgical margins and G1 tumours predicted a better prognosis and a lower recurrence rate. The evolution of surgical technique and the introduction in clinical practice of new prosthetic materials allowed larger resections, and safe and anatomical reconstruction.

The Evaluation of Marginal Gap With and Without Optical Aids: Clinicians Versus Technicians

This study investigated the reliability of visual assessment of marginal gaps in relation to the use of magnification and the operator's profession. A titanium bar was notched, simulating 40 marginal gaps, and 35 operators performed a quantitative evaluation of the incisions. Visual examination was neither sensitive nor specific, as an extreme variability of data was recorded. The precision of readers improved with magnification aids only for clinicians; technicians were significantly more accurate in evaluating the incision's width. The visual examinations were inadequate to decide the clinical acceptability of a restoration with regard to its marginal fit.

Preoperative Patch Testing In Patients Undergoing Pectus Excavatum Repair

The Nuss procedure is a minimally invasive surgery to correct pectus deformities using a stainless-steel rod containing several metals including nickel. Occasionally, devastating complications occur in patients who develop delayed type hypersensitivity to the implanted rod. A retrospective study showed the incidence of metal hypersensitivity was 2.2% in patients having undergone the Nuss procedure. Yet, if metal contact dermatitis is determined a priori, a titanium bar is customized. This case series investigated preoperative incidence of metal allergy in patients scheduled to undergo the Nuss procedure.

Cardiac magnetic resonance in patients with pectus excavatum: impact of thoracic surgery on cardiac function - a follow- up-study

Background Pectus excavatum (PE) as the most common anterior chest deformity is characterized by sternal depression with corresponding leftward displacement and rotation of the heart which is troublesome for assessment by ultrasound. Therefore CMR plays a growing role in preoperative evaluation. Indication for surgical correction is based on a diameter-based assessment of the thorax (Haller-Index, HI) and symptoms. Imaging data describing cardiac performance after surgery are rare. The aim of the study was to assess cardiac function during follow-up (FU). Methods 37 patients with PE (30 male, age 12-43 years) underwent CMR using 1.5T MRI-scanner (Avanto, Siemens Healthcare, Germany) prior to surgery and repeatedly postoperative (10 days, 3 months and 1 year). The highly experiences surgeons (more than 130 procedures/year) implanted a titan-bar (Nuss procedure) based on the usual clinical indication. CMR protocol included state of the art cine SSFP covering the left ventricle (LV) as short axis (TR 33.6 ms, TE 1.18 ms, FOV 292 × 360 mm, matrix 256 × 208, sth 7 mm without gap) and the right ventricle (RV) axial orientation (TR 34.56 ms, TE 1.21 ms, FOV 332 × 269 mm, matrix 256 × 208, sth 6 mm without gap). HI was measured on survey images (Figure 1). We quantified the enddiastolic and endsystolic volumes of LV and RV: calculated the ejection fractions (EF) and stroke volumes (SV) using CMR42 (circle cvi, Canada). Results CMR images were evaluable despite implanted titanium bars. All patients completed one year FU. HI was significantly reduced after surgery (pre: 9.9 ± 5.7 vs. post: 2.8 ± 0.5, p < 0.001) indicating a successful procedure. Pleural effusions were detectable at day 10 in almost all (24 from 25 patients) pericardial effusion in 3 and it was resolved in all completely after 1 year. There were variable findings at different FU-time-points. The most positive change in RVEF was observed at 10 days FU followed by slight reduction on 3 months and further decrease at 1 year. Despite these findings the RVEF remained significantly improved at 1 year. Interestingly, RVEF was found to change significantly from baseline to 1 year FU (p < .0001), whereas LVEF did not (p = 0.0539). RVSV and LVSV were found to change significantly from baseline to 1 year follow-up (p = 0.0018 and 0.0008, respectively). Weak correlation was found between the delta (baseline/1 year) HI compared to RVEF.

Laser welded versus resistance spot welded bone implants: analysis of the thermal increase and strength.

Introduction. The first aim of this “ex vivo split mouth” study was to compare the thermal elevation during the welding process of titanium bars to titanium implants inserted in pig jaws by a thermal camera and two thermocouples. The second aim was to compare the strength of the joints by a traction test with a dynamometer. Materials and Methods. Six pigs' jaws were used and three implants were placed on each side of them for a total of 36 fixtures. Twelve bars were connected to the abutments (each bar on three implants) by using, on one side, laser welding and, on the other, resistance spot welding. Temperature variations were recorded by thermocouples and by thermal camera while the strength of the welded joint was analyzed by a traction test. Results. For increasing temperature, means were 36.83 and 37.06, standard deviations 1.234 and 1.187, and P value 0.5763 (not significant). For traction test, means were 195.5 and 159.4, standard deviations 2.00 and 2.254, and P value 0.0001 (very significant). Conclusion. Laser welding was demonstrated to be able to connect titanium implant abutments without the risk of thermal increase into the bone and with good results in terms of mechanical strength.