Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 310
Filter
1.
Article in Chinese | WPRIM | ID: wpr-880436

ABSTRACT

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


Subject(s)
Alloys , Corrosion , Hot Temperature , Materials Testing , Stents , Surface Properties , Temperature , Titanium
2.
Rev. Ciênc. Méd. Biol. (Impr.) ; 19(3): 502-506, dez 5, 2020. tab
Article in Portuguese | LILACS | ID: biblio-1358029

ABSTRACT

Introdução: a movimentação dentária requer a aplicação de um sistema de forças que é orientado com o uso de acessórios, incluindo fios ortodônticos. Existem diversos materiais e fabricantes disponíveis no mercado, por isso é importante que o profissional conheça a composição deste material, uma vez que estará em contato com a mucosa oral, podendo sofrer corrosão e liberação de íons metálicos. Objetivo: avaliar, in vitro, o grau de corrosão de duas ligas metálicas que compõem fios ortodônticos de três fabricantes diferentes, submetidos à ciclagem de pH. Metodologia: 60 corpos de prova foram confeccionados com dois tipos de ligas metálicas (NiTi e CrNiaço 302) produzidas por três fabricantes diferentes, divididos em 6 Grupos de Testes com 10 unidades cada. Os corpos-de-prova foram submetidos à ciclagem ácida de pH 4,3, diariamente, e mantidos em estufa a 37 ° C por 14 dias. A massa foi pesada antes e após a ciclagem, por meio de balança analítica de precisão. A avaliação das características visuais dos fios foi realizada por um único observador em lupa estereomicroscópica. Resultados: a ciclagem de pH dos fios ortodônticos não promoveu perda significativa de massa ou corrosão, apesar da análise das características visuais terem mudado após a ciclagem. Conclusão: com base nos resultados do protocolo experimental estabelecido no presente estudo, a análise do comportamento das ligas de aço NiTi e CrNi ­ 302 que compõem os fios ortodônticos, frente ao desafio ácido de pH 4,3, por duas semanas, concluiu-se que esses materiais não apresentaram perdas de massa, opacidade, brilho e lisura consideradas significativas. Outros estudos são recomendados para fornecer maiores esclarecimentos sobre o tema.


Introduction: the tooth movement requires the application of a force system that is guided with the use of accessories, including orthodontic wires. There are several materials and manufacturers available on the market, so it is important that the professional knows the composition of this material, since it will be in contact with the oral mucosa, and may suffer corrosion and release metal ions. Objective: to evaluate, in vitro, the degree of corrosion of two metal alloys that make up orthodontic wires from three different manufacturers, submitted to pH cycling. Methodology: 60 specimens were made from two types of metal alloys (NiTi and CrNi ­ steel 302) produced by three different manufacturers, divided into 6 Test Groups with 10 units each. The specimens were subjected to acid pH 4.3 cycling, daily, and kept in an oven at 37 ° C for 14 days. The mass was obtained before and after cycling, using a precision analytical balance. The evaluation of the visual characteristics of the wires was performed by a single observer using a stereomicroscopic loupe. Results: the pH cycling of orthodontic wires did not promote significant loss of mass or corrosion, despite the analysis of visual characteristics having changed after cycling. Conclusion: based on the results of the experimental protocol established in the present study, the analysis of the behavior of the NiTi and CrNi ­ 302 steel alloys that make up the orthodontic wires, facing the acid challenge of pH 4.3, for two weeks, it was concluded that these materials did not present loss of mass, opacity, brightness and smoothness considered significant. Other studies are recommended to provide further clarification on the topic.


Subject(s)
Orthodontic Wires , Orthodontics , Corrosion
3.
Int. j. odontostomatol. (Print) ; 14(3): 442-447, 2020. tab, graf
Article in English | LILACS | ID: biblio-1114919

ABSTRACT

Dietary supplements are being consumed with an increasingly high frequency among sports practitioners, whether at professional and/or amateur level. The supplements contain some nutritional properties in their composition, so they can dissolute the hydroxyapatite crystals of the enamel and favor the process of dental corrosion. The objective was to measure the corrosive power of protein-based supplementation (Whey Protein), under conditions that resemble the use of the supplement by the athletes, increasing the ecological validity of the study. The teeth of the test group (TG) were placed in contact with the Whey protein solution and then exposed to artificial saliva. And the teeth of the control group (CG) were exposed only to artificial saliva. The analysis occurred in natural healthy molar teeth, so that each tooth of the TG was immersed in 50 mL of supplement for 1.5 minutes and then placed in contact with the artificial saliva for 30 seconds. The same procedure was performed 5 times a day for 30, 60, 90, 120, 150 and 180 days. Each group, in its time (TG0 to TG180), underwent analysis of superficial roughness with the aid of optical profilometer (Talysurf CCI®, 3D model). The control group (CG) did not change its superficial roughness. Half of the teeth of the test group (TG) suffered loss of enamel surface. The values, in micrometers, of surface loss of the TG samples were 1.21; 2.1; 2.0; 1.04; 0.97; 0.8; 0.53; 1.14; 1.9; 2.0; 1.66; 1.80. The dietary supplement (Whey protein®) may be a potential cause of the dental corrosion process, considering the demineralization of hydroxyapatite that occurs along with the surface enamel loss.


Los suplementos dietéticos se consumen con una frecuencia cada vez más alta entre los practicantes de deportes, sea a nivel profesional y / o aficionado. Los suplementos contienen algunas propiedades nutricionales en su composición, por lo que pueden disolver los cristales de hidroxiapatita del esmalte y favorecer el proceso de corrosión dental. El objetivo fue medir el poder corrosivo de la suplementación a base de proteínas (proteína de suero), en condiciones que se asemejan al uso del suplemento por parte de los atletas, aumentando la validez ecológica del estudio. Los dientes del grupo de prueba (TG) se pusieron en contacto con la solución de proteína de suero y luego se expusieron a saliva artificial. Y los dientes del grupo de control (CG) estuvieron expuestos solo a saliva artificial. El análisis se realizó en dientes molares sanos naturales, cada diente del TG se sumergió en 50 ml de suplemento durante 1,5 minutos y luego se puso en contacto con la saliva artificial durante 30 segundos. El mismo procedimiento se realizó 5 veces al día durante 30, 60, 90, 120, 150 y 180 días. Cada grupo, en su momento (TG0 a TG180), se sometió a un análisis de rugosidad superficial con la ayuda de un perfilómetro óptico (Talysurf CCI®, modelo 3D). El grupo de control (CG) no cambió su rugosidad superficial. La mitad de los dientes del grupo de prueba (TG) sufrieron pérdida de la superficie del esmalte. Los valores, en micrómetros, de pérdida de superficie de las muestras de TG fueron 1.21; 2.1; 2,0; 1.04; 0,97; 0.8; 0,53; 1.14; 1.9; 2,0; 1,66; 1.80. El suplemento dietético (Whey protein®) puede ser una causa potencial del proceso de corrosión dental, considerando la desmineralización de la hidroxiapatita que ocurre junto con la pérdida de esmalte superficial.


Subject(s)
Humans , Sports , Dietary Proteins/adverse effects , Tooth Demineralization/chemically induced , Dietary Supplements/adverse effects , Saliva/chemistry , In Vitro Techniques , Pilot Projects , Control Groups , Durapatite , Corrosion , Dental Etching , Hydrogen-Ion Concentration
4.
Article in Korean | WPRIM | ID: wpr-820823

ABSTRACT

OBJECTIVES: The aim of this study was to investigate the effects of some commercial calamansicontaining beverages on the sound surface of bovine teeth as well as the dental erosion inhibitory effects of calcium.METHODS: The pH and titratable acidity of six kinds of commercially available calamansi beverages were determined. Further, 3% calcium was added to the calamansi beverage Oranssi in the experimental group to confirm its dental erosion inhibitory effect. Jeju Samdasoo was used in the negative control group and Coca-Cola in the positive control group. After immersing the sound teeth specimens for 10 min, surface microhardness was measured using the Vickers hardness number (VHN), and surface changes in specimens were observed under a scanning electron microscope.RESULTS: The average pH of the commercial calamansi beverages was 2.54±0.22. After 10 min of treatment with each experimental beverage, the surface hardness difference (ΔVHN) was highest in the Coca-Cola group (−49.05±12.59), followed by the Oranssi calamansi group (−43.77±13.70), 3% calcium-added Oranssi calamansi group (−2.71±12.58), and Samdasoo group (14.03±20.79). There was no significant difference between the bottled water and calcium-added Oranssi calamansi groups or between the Coca-Cola and Oranssi calamansi groups (P>0.05). However, there was a significant difference in the surface hardness between the bottled water and CocaCola groups (P<0.05). On scanning electron microscopy, the Samdasoo group showed a smooth surface without any loss, but Coca-Cola and Oranssi calamansi groups showed a rough surface due to erosion. However, although fine cracks and porosities were seen in the calcium-added Oranssi calamansi group, surfaces in the group were much smoother than those in the Oranssi calamansi group.CONCLUSIONS: Calamansi beverages of low pH may cause corrosion of the tooth surface, and the addition of calcium to the calamansi beverages inhibits demineralization of the tooth surface. Therefore, it is necessary to consider the risk of dental erosion when drinking calamansi beverages of low pH.


Subject(s)
Beverages , Calcium , Corrosion , Dental Enamel , Drinking , Drinking Water , Hardness , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Porosity , Tooth
5.
Braz. J. Pharm. Sci. (Online) ; 55: e18148, 2019. tab, graf, ilus
Article in English | LILACS | ID: biblio-1039038

ABSTRACT

According to Anvisa risk rating, hypodermic needles offer medium risk to the user's health. This study discussed the importance of the corrosion resistance test in tubes of hypodermic needles, in the product quality control. A review of cannulas of hypodermic needles was carried out according to ISO 9626:2003 and 9259:1997 ABNT NBR. For the results evaluation, a scale which classifies the extent of corrosion was adjusted. 174 samples of PNI needles from 17 States and 9 different record holders were analyzed. According to the methodology of ISO 9626:2003, 100% of the samples were considered satisfactory. However, in accordance with the methodology of ISO 9259:1997, 97.1% of the samples were rejected. Irregularities can lead to impairment of product quality, resulting in risks to the consumer's health. Since 2011 the product has undergone certification, so it is necessary to reflect on the importance of corrosion resistance testing and mandatory certification for health monitoring.


Subject(s)
Quality Control , Corrosion , Needles/standards , Product Surveillance, Postmarketing , Brazil/ethnology , Chromium/analysis , Cannula , Legislation as Topic/standards
6.
Arq. odontol ; 55: 1-12, jan.-dez. 2019. ilus, tab
Article in Portuguese | LILACS, BBO | ID: biblio-1052824

ABSTRACT

Objetivo: Avaliar as alterações químicas presentes na superfície metálica de limas endodônticas fraturadas em canais radiculares, in vitro, após a inoculação intrarradicular de culturas de BRS de três cepas microbianas, Desulfovibrio desulfuricans (uma cepa oral e outra ambiental) e Desulfovibrio fairfieldensis. Métodos: foram analisadas 5 limas kerr #90, sendo uma Lima Kerr nova, sem tratamento, e as outras 4 limas fraturadas dentro de canais radiculares in vitro, com posterior inoculação de Desulfovibrio desulfuricans, cepa oral e ambiental, e Desulfovibrio fairfieldensis e um grupo controle sem inoculação bacteriana, por 477 dias. Os grupos foram analisados no modo EDS (Espectrometria de Energia Dispersiva de Raios-x) do microscópio eletrônico de varredura (FEI-Inspect-S50). Resultados:A presença do S, Cl e O foram relacionados ao processo biocorrosivo, assim como a redução dos elementos de liga nesta área. Conclusão:As análises no modo EDS demonstraram biocorrosão ao longo da superfície metálica das limas quando empregado o biofármaco BACCOR, nas três diferentes cepas empregadas, indicada pela redução dos elementos formadores da liga metálica, Fe, Ni e Cr, com a associação da presença de elementos indicadores de biocorrosão como O, Cl e S. (AU)


Aim:To evaluate the chemical alterations present on the metallic surface of root canal fractured endodontic files in vitro after the intraradicular inoculation of BRS cultures of three microbial strains, Desulfovibrio desulfuricans (one oral and one environmental strain), and Desulfovibrio fairfieldensis. Methods: Five kerr #90 files were analyzed, one new untreated Kerr file and the other 4 files fractured within root canals in vitro, with a subsequent inoculation of Desulfovibrio desulfuricans (oral and environmental strains), and Desulfovibrio fairfieldensis, as well as a control group without bacterial inoculation for 477 days. The groups were analyzed using the scanning electron microscope (FEI-Inspect-S50) EDS (X-ray Dispersive Energy Spectrometry) mode. Results:The presence of S, Cl, and O were related to the biocorrosive process, as well as the reduction of alloying elements in this area. Conclusion: The EDS mode analysis showed biocorrosion along the metallic surface of the files when the BACCOR biopharmaceutical was used in the three different strains employed in this study, indicated by the reduction of the alloying elements ­ Fe, Ni, and Cr ­ with the association of the presence of indicator elements of biocorrosion, such as O, Cl, and S. (AU)


Subject(s)
Biological Products , Corrosion , Culture Media , Dental Alloys , Dental Instruments , Desulfovibrio desulfuricans , Dental Pulp Cavity , Desulfovibrio , In Vitro Techniques , Endodontics
7.
Anatomy & Cell Biology ; : 191-195, 2019.
Article in English | WPRIM | ID: wpr-762213

ABSTRACT

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.


Subject(s)
Adipose Tissue , Catheters , Coronary Sinus , Coronary Vessels , Corrosion , Ligation , Methods , Polyurethanes
8.
Article in Korean | WPRIM | ID: wpr-761429

ABSTRACT

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.


Subject(s)
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
9.
Article in Korean | WPRIM | ID: wpr-786024

ABSTRACT

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.


Subject(s)
Beverages , Calcium , Corrosion , Dentin , Hardness , Humans , Hydrogen-Ion Concentration , Immersion , Lactic Acid , Prunus domestica , Tooth
10.
Article in English | WPRIM | ID: wpr-764784

ABSTRACT

PURPOSE: The purpose of this study was to investigate the corrosion behaviors of dental implant alloy after micro-sized surface modification in electrolytes containing Mn ion. MATERIALS AND METHODS: Mn-TiO₂ coatings were prepared on the Ti-6Al-4V alloy for dental implants using a plasma electrolytic oxidation (PEO) method carried out in electrolytes containing different concentrations of Mn, namely, 0%, 5%, and 20%. Potentiodynamic method was employed to examine the corrosion behaviors, and the alternating-current (AC) impedance behaviors were examined in 0.9% NaCl solution at 36.5℃±1.0℃ using a potentiostat and an electrochemical impedance spectroscope. The potentiodynamic test was performed with a scanning rate of 1.667 mV s⁻¹ from −1,500 to 2,000 mV. A frequency range of 10⁻¹ to 10⁵ Hz was used for the electrochemical impedance spectroscopy (EIS) measurements. The amplitude of the AC signal was 10 mV, and 5 points per decade were used. The morphology and structure of the samples were examined using field-emission scanning electron microscopy and thin-film X-ray diffraction. The elemental analysis was performed using energy-dispersive X-ray spectroscopy. RESULT: The PEO-treated surface exhibited an irregular pore shape, and the pore size and number of the pores increased with an increase in the Mn concentration. For the PEO-treated surface, a higher corrosion current density (I(corr)) and a lower corrosion potential (E(corr)) was obtained as compared to that of the bulk surface. However, the current density in the passive regions (I(pass)) was found to be more stable for the PEO-treated surface than that of the bulk surface. As the Mn concentration increased, the capacitance values of the outer porous layer and the barrier layer decreased, and the polarization resistance of the barrier layers increased. In the case of the Mn/Ca-P coatings, the corroded surface was found to be covered with corrosion products. CONCLUSION: It is confirmed that corrosion resistance and polarization resistance of PEO-treated alloy increased as Mn content increased, and PEO-treated surface showed lower current density in the passive region.


Subject(s)
Alloys , Corrosion , Dental Implants , Dielectric Spectroscopy , Electric Impedance , Electrolytes , Manganese , Methods , Microscopy, Electron, Scanning , Plasma , Spectrum Analysis , X-Ray Diffraction
11.
Article in Korean | WPRIM | ID: wpr-759673

ABSTRACT

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.


Subject(s)
Corrosion , Durapatite , Immersion , Membranes , Nanotubes , Titanium , Wettability
12.
Article in Korean | WPRIM | ID: wpr-759665

ABSTRACT

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.


Subject(s)
Beer , Beverages , Carbonated Beverages , Citrus sinensis , Corrosion , Eating , Energy Drinks , Immersion , Methods , Tooth , Water
13.
Hip & Pelvis ; : 190-195, 2018.
Article in English | WPRIM | ID: wpr-740427

ABSTRACT

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.


Subject(s)
Aged , Corrosion , Joint Dislocations , Female , Follow-Up Studies , Hip Joint , Hip , Humans , Leg , Neck , Prostheses and Implants , Welding
14.
Biomedical Engineering Letters ; (4): 337-344, 2018.
Article in English | WPRIM | ID: wpr-717990

ABSTRACT

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.


Subject(s)
Amputation , Certification , Corrosion , Fatigue , Freezing , Humans , Israel , Joints , Metals , Methods , Plastics , Russia , Titanium
15.
Article in Chinese | WPRIM | ID: wpr-771541

ABSTRACT

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.


Subject(s)
China , Chromium , Corrosion , Medicine, Chinese Traditional
16.
Rev. odontol. Univ. Cid. São Paulo (Online) ; 29(3): [237-242], set-dez. 2017. figuras
Article in Portuguese | LILACS, BBO | ID: biblio-908721

ABSTRACT

Objetivo: Determinar o pH crítico para ocorrer a corrosão de arcos NiTi em soluções de flúor a 1,1%, variando o pH de 3,5 a 7,0. Materiais e Métodos: Doze amostras com 10mm de comprimento de fio superelástico NiTi 0017 x 0025 (Abzil), obtidas do segmento distal dos arcos. As amostras foram aleatoriamente separadas e imersas dentro de recipientes contendo 40ml de seis soluções (água, soluções fluoretadas com pH: 3,5; 4,0; 4,5; 5,0; 5,5; 6,0; 6,5 e 7,0), sob uma mesa agitadora durante 90 minutos. Todas as amostras foram, então, levadas ao MEV. As imagens das amostras imersas em água e soluções fluoretadas com pH 7,0, 6,5 e 6,0 não se apresentaram diferentes, no entanto a partir da solução fluoretada com pH 5,5, as imagens superficiais apresentaram características diferentes dos grupos anteriores. Conclusão: Com base nos resultados obtidos neste estudo, o pH crítico para corrosão de arcos NiTi em soluções de flúor a 1,1% parece estar entre 6,0 e 5,5


Objective: To determine the critical pH to occur corrosion of NiTi arches in 1.1% fluoride solutions by varying the pH between 3.5 and 7.0. Materials and Methods: Twelve samples of 10 mm length superelastic NiTi wire 0017 x 0025 (Abzil) obtained in the distal segment of the arcs. The samples were randomly separated and immersed in 40 ml of six solutions (water, fluoride solutions with pH: 3.5; 4.0; 4.5; 5.0; 5.5; 6.0; 6.5 and 7.0) under a shaker table for 90 minutes. All samples were observed under SEM. The images of the samples immersed in water and fluoride solutions at pH 7.0, 6.5 and 6.0 did not show differences, however from the fluoride solution at pH 5.5, the surface characteristics of images presented differences from above groups. Conclusion: Based on the results obtained in this study the critical pH for corrosion of NiTi arches in fluoride solutions to 1.1% appears to be between 6.0 and 5.5


Subject(s)
Corrosion , Fluorine , Solutions
17.
Article in English | WPRIM | ID: wpr-25855

ABSTRACT

PURPOSE: The purpose of this study was to investigate the electrochemical characteristics of nanotubular Ti-25Nb-xZr ternary alloys for dental implant materials. MATERIALS AND METHODS: Ti-25Nb-xZr alloys with different Zr contents (0, 3, 7, and 15 wt.%) were manufactured using commercially pure titanium (CP-Ti), niobium (Nb), and zirconium (Zr) (99.95 wt.% purity). The alloys were prepared by arc melting in argon (Ar) atmosphere. The Ti-25Nb-xZr alloys were homogenized in Ar atmosphere at 1,000℃ for 12 hours followed by quenching into ice water. The microstructure of the Ti-25Nb-xZr alloys was examined by a field emission scanning electron microscope. The phases in the alloys were identified by an X-ray diffractometer. The chemical composition of the nanotube-formed surfaces was determined by energy-dispersive X-ray spectroscopy. Selforganized TiO₂ was prepared by electrochemical oxidation of the samples in a 1.0 M H₃PO₄+0.8 wt.% NaF electrolyte. The anodization potential was 30 V and time was 1 hour by DC supplier. Surface wettability was evaluated for both the metallographically polished and nanotube-formed surfaces using a contact-angle goniometer. The corrosion properties of the specimens were investigated using a 0.9 wt.% aqueous solution of NaCl at 36℃±5℃ using a potentiodynamic polarization test. RESULT: Needle-like structure of Ti-25Nb-xZr alloys was transform to equiaxed structure as Zr content increased. Nanotube formed on Ti-25Nb-xZr alloys show two sizes of nanotube structure. The diameters of the large tubes decreased and small tubes increased as Zr content increased. The lower contact angles for nanotube formed Ti-25NbxZr alloys surfaces showed compare to non-nanotube formed surface. The corrosion resistance of alloy increased as Zr content increased, and nanotube formed surface showed longer the passive regions compared to non-treatment surface. CONCLUSION: It is confirmed that corrosion resistance of alloy increased as Zr content increased, and nanotube formed surface has longer passive region compared to without treatment surface.


Subject(s)
Alloys , Argon , Atmosphere , Corrosion , Dental Implants , Freezing , Ice , Nanotubes , Niobium , Spectrum Analysis , Titanium , Water , Wettability , Zirconium
18.
Article in English | WPRIM | ID: wpr-71181

ABSTRACT

PURPOSE: In this study, three bioceramic materials, [IPS Empress CAD (Ivoclar), IPS e.max CAD (Ivoclar), and Lava Ultimate CAD (3M ESPE)] were treated with three commercial mouthrinses [Listerine, Tantum Verde, and Klorhex]; and changes in colour reflectance and surface roughness values were then quantitatively assessed. MATERIALS AND METHODS: One hundred and twenty ceramic samples, with dimensions of 2 × 12 × 14 mm, were prepared and divided into nine sample groups, except three control samples. The samples were immersed in the mouthrinse solutions for 120 hrs, and changes in colour reflectance and surface roughness values were measured by UV light spectrophotometry (Vita Easyshade; VITA Zahnfabrik) and by profilometer device (MitutoyoSurftest SJ-301), respectively. The change of surface roughness was inspected by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). RESULTS: There was a positive correlation between the ΔE and increase in the surface roughness. Two of the ceramic materials, IPS Empress and Lava Ultimate, were affected significantly by the treatment of the mouthrinse solutions (P<.05). The most affecting solution was Tantum Verde and the most affected material was Lava Ultimate. As expected, the most resistant material to ΔE and chemical corrosion was IPS e max CAD among the materials used. CONCLUSION: This work implied that mouthrinse with lower alcohol content had less deteriorating effect on colour and on the surface morphology of the bioceramic materials.


Subject(s)
Benzydamine , Ceramics , Corrosion , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Refractometry , Spectrophotometry , Ultraviolet Rays
19.
Neurointervention ; : 31-39, 2017.
Article in English | WPRIM | ID: wpr-730309

ABSTRACT

PURPOSE: To better understand the performance of four commercially available neurovascular stents in intracranial aneurysm embolization, the stents were compared in terms of their basic morphological and mechanical properties. MATERIALS AND METHODS: Four different types of stents that are currently being used for cerebral aneurysm embolization were prepared (two stents per type). Two were laser-cut stents (Neuroform and Enterprise) and two were braided from a single nitinol wire (LEO and LVIS stents). All were subjected to quantitative measurements of stent size, pore density, metal coverage, the force needed to load, push, and deploy the stent, radial force on deployment, surface roughness, and corrosion resistance. RESULTS: Compared to their nominal diameters, all stents had greater diameters after deployment. The length generally decreased after deployment. This was particularly marked in the braided stents. The braided stents also had higher pore densities than the laser-cut stents. Metal coverage was highest in the LEO stent (14%) and lowest in the Enterprise stent (5%). The LIVS stent had the highest microcatheter loading force (81.5 gf). The LEO stent had the highest passage force (55.0 gf) and deployment force (78.9 gf). The LVIS and LEO stents had the highest perpendicular (37.1 gf) and circumferential (178.4 gf) radial forces, respectively. The Enterprise stent had the roughest stent wire, followed by the LVIS, LEO, and Neuroform stents. CONCLUSION: The four neurovascular stent types differed in terms of morphological and physical characteristics. An understanding of this diversity may help to decide which stent is most suitable for specific clinical situations.


Subject(s)
Corrosion , Intracranial Aneurysm , Stents
20.
Article in English | WPRIM | ID: wpr-12031

ABSTRACT

OBJECTIVE: The purpose of this study was to examine the effect of commercially available fluoride-containing oral rinses on the corrosion behavior of titanium alloys, which are the main components of orthodontic miniscrews. METHODS: Four commercially available oral rinses (solution A, pH 4.46/260 ppm fluoride; solution B, pH 4.41/178 ppm fluoride; solution C, pH 6.30/117 ppm fluoride; and solution D, pH 4.17/3.92 ppm fluoride) were tested on titanium alloy (Ti-6Al-4V) circular plates, and saline was used as the control. The open-circuit potential and potentiodynamic polarization of these materials were measured. Thereafter, all samples were evaluated under a field-emission scanning electron microscope. RESULTS: Among the tested oral rinses, except solution D, the more the fluoride content was, the greater was the corrosion potential downtrend; the corrosion resistance of the titanium alloy sample was also lowered significantly (p < 0.05). Field-emission scanning electron microscopic analysis of the surface morphology of the titanium alloy samples revealed that all samples had some defects, crevices, or pitting after exposure to the oral rinses than before treatment. In particular, the samples in solution A showed the most changes. CONCLUSIONS: Commercially available oral rinses having a high fluoride concentration and a low pH may reduce the corrosion resistance of titanium alloys used in dental appliances such as orthodontic titanium miniscrews and brackets.


Subject(s)
Alloys , Corrosion , Fluorides , Hydrogen-Ion Concentration , Titanium
SELECTION OF CITATIONS
SEARCH DETAIL