Effects of heat treatment conditions (including temperature and time) on the shape memory recovery and corrosion resistance of NiTi self-expanding vascular stents were studied based on working mechanism and clinical use. The
Alloys ; Corrosion ; Hot Temperature ; Materials Testing ; Stents ; Surface Properties ; Temperature ; Titanium

Aiming at the medical practice problems of the surgical steel medical instruments, such as the crevice corrosion, the poor mechanical compatibility and the Ni, Cr plasma exudation, the laser deposition of Ti-6Al-4V alloy cladding layer at the local functional area as alternative coating was proposed and realized as a new process method. The accurate element content and good formability Ti-6Al-4V cladding powder was chosen, the low power and high duty cycle optimized laser process was adopt, the alternative coating of good fusion and low dilution was prepared. Through the elemental line scanning, the interface microstructure analysis and the experiments of basic mechanical properties, the basic properties of the cladding were characterized and verified. The experiments results showed that, the Ti, Al and V contents of the top coating were respectively about 88%, 4.9% and 3.9%, no sensitizing ions such as Cr and Ni were detected. Initial equiaxed α phase, flake β phase dist were distributed in the coating and interface, the α' martensite was precipitated at the boundary of the flake β phase, some refined granular β phase dispersion pinned to the grain boundary of basket structure. The microhardness of cladding layer was 352.08~312.76 HV_0.1. The friction coefficient of the cladding layer was about 0.22~0.65. A new technology and method reference for improving and upgrading the performance of surgical medical devices is provided by this research.
Alloys ; Corrosion ; Materials Testing ; Steel ; Titanium

In the oral cavity, the teeth undergo wear and corrosion throughout their lives. Progressive and constant tooth wear is a natural phenomenon of aging, but wear and corrosion due to specific factors are pathological factors. It can cause pathological damage of the occlusal surface, aesthetic problems, dimensional loss and jaw joint disorders. This case is a 26-year-old female patient with general tooth abrasion and erosion on the entire dentition. Diagnostic wax-up was fabricated based on the information including digital facial analysis, physiological stabilization, and evaluation of anterior crown length. Through the digital analysis, the necessary guides for crown lengthening were prepared and the mastication function and esthetics were evaluated by using temporary crowns. Definitive prosthesis was fabricated with the zirconia restorations. The results were satisfactory when they were observed 3 months of follow-up.
Adult ; Aging ; Corrosion ; Crown Lengthening ; Crowns ; Dentition ; Esthetics ; Female ; Follow-Up Studies ; Humans ; Jaw ; Joints ; Mastication ; Mouth Rehabilitation ; Mouth ; Prostheses and Implants ; Tooth Abrasion ; Tooth Erosion ; Tooth Wear ; Tooth

Polyurethane foam (PU foam) is a new material which is being used in producing both macro-anatomical and micro-anatomical specimens. PU foam is simple to use, without need for special equipment. The present study was carried out to evaluate morphology of coronary sinus and its tributaries. During the study, we encountered few problems in carrying out injections. Coronary sinus and its tributaries were difficult to cannulate since the coronary sinus lacks a vascular stem, around which ligature can be tied before injection so that the cannula can be held in place. In contrast, in majority of the organs it is easy to inject since they possess tubular vascular stem to hold the cannula in place. A new device was developed which could be used to cannulate coronary sinus orifice to inject the casting media. The second problem we faced was saponification of adipose tissue. This made corrosion of the soft tissue difficult. Hence in this study, we describe the device we have developed to place in the coronary sinus orifice, and how saponified adipose tissue was taken care during the actual maceration step.
Adipose Tissue ; Catheters ; Coronary Sinus ; Coronary Vessels ; Corrosion ; Ligation ; Methods ; Polyurethanes

OBJECTIVES: We investigated the effects of commercial plum beverage on the dentin surface that could be exposed to caries, gliopathy, and abrasion to investigate the inhibitory effects of dentin corrosion.METHODS: The experimental beverages were Jeju Samdasoo (Group 1, negative control), Coca-Cola (Group 2, positive control), Chorok Maesil (Group 3), and Chorok Maesil with 3% calcium lactate added (Group 4). The specimens were prepared and divided into 4 groups of 12 each. The pH of the experimental beverages was measured using a pH meter, and specimen surface hardness was assessed according to the Vickers hardness number (VHN). The specimens were immersed in the experimental beverage for 1, 3, 5, 10, and 15 minutes. Then, we obtained the average VHN by measuring surface microhardness. Measures of surface microhardness were compared using the paired t-test before and after 15 minutes of immersion in each of the four beverages. Between-group differences in surface microhardness were compared using one-way analysis of variance and the Tukey test after the analysis.RESULTS: After 15 minutes of immersion in the experimental beverages, there was no significant difference in surface microhardness in group 1 (P>0.05). There were significant differences in groups 2, 3, and 4 (P < 0.05). The difference in surface microhardness before and after immersion for 15 minutes was highest in group 3 (−18.1±2.55), followed by group 2 (−13.0±3.53) and group 4 (−7.79±4.47). In group 1, the difference was −1.52±4.30. Moreover, there was a significant difference in each group (P < 0.05). After 10 minutes of immersion, surface microhardness tended to rapidly decrease.CONCLUSIONS: Patients who regularly ingest a commercially available plum drink with low pH should be provided dietary guidance on the risk of dental erosion. Calcium additives should be considered when producing plum beverage products.
Beverages ; Calcium ; Corrosion ; Dentin ; Hardness ; Humans ; Hydrogen-Ion Concentration ; Immersion ; Lactic Acid ; Prunus domestica ; Tooth

Modular femoral prostheses are characterized by a second neck-stem junction. This modularity provides many clinical benefits including hip offset restoration, intraoperative leg length and anteversion adjustment. Although, this extra junction in modular femoral prostheses can contribute to catastrophic consequences like fracture, cold welding, corrosion and fretting of the modularity. However, only few complications related to the modularity itself have been reported in the literature. We report a unique case of neck-stem component dissociation without dislocation of the R-120PC™ Modular Stem (DJO Surgical). Our 71-year-old obese female patient underwent cementless hip replacement 5 years ago. Following radiographic confirmation of neck-stem dissociation open reduction was performed and wiring fixation was applied to secure the neck to the stem. After reduction and fixation, hip joint was stable, and our patient returned to her daily routine 2.5 months postoperatively. The last follow up was at 12 months after surgery with excellent radiographic and clinical evaluation.
Aged ; Corrosion ; Dislocations ; Female ; Follow-Up Studies ; Hip Joint ; Hip ; Humans ; Leg ; Neck ; Prostheses and Implants ; Welding

Additive manufacturing (AM) is an alternative metal fabrication technology. The outstanding advantage of AM (3D-printing, direct manufacturing), is the ability to form shapes that cannot be formed with any other traditional technology. 3D-printing began as a new method of prototyping in plastics. Nowadays, AM in metals allows to realize not only net-shape geometry, but also high fatigue strength and corrosion resistant parts. This success of AM in metals enables new applications of the technology in important fields, such as production of medical implants. The 3D-printing of medical implants is an extremely rapidly developing application. The success of this development lies in the fact that patient-specific implants can promote patient recovery, as often it is the only alternative to amputation. The production of AM implants provides a relatively fast and effective solution for complex surgical cases. However, there are still numerous challenging open issues in medical 3D-printing. The goal of the current research review is to explain the whole technological and design chain of bio-medical bone implant production from the computed tomography that is performed by the surgeon, to conversion to a computer aided drawing file, to production of implants, including the necessary post-processing procedures and certification. The current work presents examples that were produced by joint work of Polygon Medical Engineering, Russia and by TechMed, the AM Center of Israel Institute of Metals. Polygon provided 3D-planning and 3D-modelling specifically for the implants production. TechMed were in charge of the optimization of models and they manufactured the implants by Electron-Beam Melting (EBM®), using an Arcam EBM® A2X machine.
Amputation ; Certification ; Corrosion ; Fatigue ; Freezing ; Humans ; Israel ; Joints ; Metals ; Methods ; Plastics ; Russia ; Titanium*

Chromium has been discovered for more than two hundred years, and it has advantages of wear-resisting, high temperature, corrosion resistance and so on. Chromium has been widely used in industrial production and received extensive attention in China and abroad. Detailed limit standards have been set for chromium in food and fishery product, and chromium can also be enriched in many traditional Chinese medicines. Besides, the toxicities of different chromium speciation are quite different, and thus morphological analysis is necessary. However, the transformation or migration is easily happened among different speciation which brings difficulties to research and analysis. This article summarizes the research status of chromium and its aims to provide reference for scientific research and pollution prevention of chromium.
China ; Chromium ; analysis ; Corrosion ; Medicine, Chinese Traditional

This study was conducted to analyze the effects of beverages on tooth corrosion by selecting drinks that are enjoyed by modern people. Drinks were selected for carbonated beverages (Coca Cola), energy drinks (Red Bull), orange juice, beer (Hite) and water (Evian). Bovine tooth was immersed for 1 hour, 24 hours and 48 hours. The root mean square (RMS) values were obtained by scanning the bovine tooth at pre-immersion and immersion time after impression making. Two-way ANOVA, one-way ANOVA, and Tukey-test were used to compare differences between groups (α=0.05). The RMS value tended to increase with longer immersion times in all beverages, and there was a significant difference (p < 0.05) between before immersion-1hr and before immersion-48 hr. The mean of RMS according to the type of beverage was significantly different and there was a significant difference according to the change of immersion time (p < 0.05). In order to prevent tooth corrosion, it is necessary to change the method of ingestion or to reduce the time of ingestion.
Beer ; Beverages ; Carbonated Beverages ; Citrus sinensis ; Corrosion ; Eating ; Energy Drinks ; Immersion ; Methods ; Tooth ; Water

The purpose of this study was to investigate the effects of the anodization and cyclic calcification treatment on the surface characteristic and bioactivity of the titanium thin sheet in order to obtain basic data for the production of bioactive titanium membrane. A 30×20×0.08 mm titanium sheets were prepared, and then they were pickled for 10 seconds in the solution which was mixed with HNO₃: HF: H₂O in a ratio of 12: 7: 81. The TiO₂ nanotube layer was formed to increase the specific surface area of the titanium, and then the cyclic calcification treatment was performed to induce precipitation of hydroxiapatite by improvement of the bioactivity. The corrosion resistance test, wettability test and immersion test in simulated body solution were conducted to investigate the effect of these surface treatments. The nanotubes formed by the anodization treatment have a dense structure in which small diameter tubes are formed between relatively large diameter tubes, and their inside was hollow and the outer walls were coupled to each other. The hydroxyapatite precipitates were well combined on the nanotubes by the penetration into the nanotube layer by successive cyclic calcification treatment, and the precipitation of hydroxyapatite tended to increase proportionally after immersion in simulated body solution as the number of cycles increased. In conclusion, it was confirmed that induction of precipitation of hydroxyapatite by cyclic calcification treatment after forming the nanotube TiO₂ nanotube layer on the surface of the titanium membrane can contribute to improvement of bioactivity.
Corrosion ; Durapatite ; Immersion ; Membranes ; Nanotubes ; Titanium ; Wettability