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Effects of AS-cast and wrought cobalt-chrome-molybdenum and titanium-aluminium-vanadium alloys on cytokine gene expression and protein secretion in J774A.1 macrophages  [PDF]
S S Jakobsen,A Larsen,M Stoltenberg,J M Bruun
European Cells and Materials (ECM) , 2007,
Abstract: Insertion of metal implants is associated with a possible change in the delicate balance between pro- and anti-inflammatory proteins, probably leading to an unfavourable predominantly pro-inflammatory milieu. The most likely cause is an inappropriate activation of macrophages in close relation to the metal implant and wear-products. The aim of the present study was to compare surfaces of as-cast and wrought Cobalt-Chrome-Molybdenum (CoCrMo) alloys and Titanium-Aluminium-Vanadium (TiAlV) alloy when incubated with mouse macrophage J774A.1 cell cultures. Changes in pro- and anti-inflammatory cytokines [TNF-alpha, IL-6, IL-alpha, IL-1beta, IL-10] and proteins known to induce proliferation [M-CSF], chemotaxis [MCP-1] and osteogenesis [TGF-beta, OPG] were determined by ELISA and Real Time reverse transcriptase - PCR (Real Time rt-PCR). Lactate dehydrogenase (LDH) was measured in the medium to asses the cell viability. Surface properties of the discs were characterised with a profilometer and with energy dispersive X-ray spectroscopy. We here report, for the first time, that the prosthetic material surface (non-phagocytable) of as-cast high carbon CoCrMo reduces the pro-inflammatory cytokine IL-6 transcription, the chemokine MCP-1 secretion, and M-CSF secretion by 77 %, 36 %, and 62 %, respectively. Furthermore, we found that reducing surface roughness did not affect this reduction. The results suggest that as-cast CoCrMo alloy is more inert than wrought CoCrMo and wrought TiAlV alloys and could prove to be a superior implant material generating less inflammation which might result in less osteolysis.
Titanium dental implant surfaces
Elias, Carlos Nelson;
Matéria (Rio de Janeiro) , 2010, DOI: 10.1590/S1517-70762010000200008
Abstract: osseointegration has been defined as "a direct structural and functional connection between ordered, living bone and the surface of a load-carrying implant". however, titanium and its alloys cannot directly bond to living bone after being implanted into the body. the osseointegration of titanium dental implants is critically dependent on the implant surface properties. various surface modifications have been proposed in order to provide commercially pure titanium with bioactive bone bonding ability. in the present work, the titanium dental implant surface morphology was modified by acid etching and electrochemical treatments with the purpose of enhancing tissue response, and decreasing the waiting time for implant loading. the results show that surface morphology, topography, roughness and chemical composition were changed by the treatments and these changes has a significant influence on osseointegration. the best results were observed in the samples submitted to the electrochemical treatment.
Cobalt-Alloy Implant Debris Induce HIF-1α Hypoxia Associated Responses: A Mechanism for Metal-Specific Orthopedic Implant Failure  [PDF]
Lauryn Samelko, Marco S. Caicedo, Seung-Jae Lim, Craig Della-Valle, Joshua Jacobs, Nadim J. Hallab
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0067127
Abstract: The historical success of orthopedic implants has been recently tempered by unexpected pathologies and early failures of some types of Cobalt-Chromium-Molybdenum alloy containing artificial hip implants. Hypoxia-associated responses to Cobalt-alloy metal debris were suspected as mediating this untoward reactivity at least in part. Hypoxia Inducible Factor-1α is a major transcription factor involved in hypoxia, and is a potent coping mechanism for cells to rapidly respond to changing metabolic demands. We measured signature hypoxia associated responses (i.e. HIF-1α, VEGF and TNF-α) to Cobalt-alloy implant debris both in vitro (using a human THP-1 macrophage cell line and primary human monocytes/macrophages) and in vivo. HIF-1α in peri-implant tissues of failed metal-on-metal implants were compared to similar tissues from people with metal-on-polymer hip arthroplasties, immunohistochemically. Increasing concentrations of cobalt ions significantly up-regulated HIF-1α with a maximal response at 0.3 mM. Cobalt-alloy particles (1 um-diameter, 10 particles/cell) induced significantly elevated HIF-1α, VEGF, TNF-α and ROS expression in human primary macrophages whereas Titanium-alloy particles did not. Elevated expression of HIF-1α was found in peri-implant tissues and synovial fluid of people with failing Metal-on-Metal hips (n = 5) compared to failed Metal-on-Polymer articulating hip arthroplasties (n = 10). This evidence suggests that Cobalt-alloy, more than other metal implant debris (e.g. Titanium alloy), can elicit hypoxia-like responses that if unchecked can lead to unusual peri-implant pathologies, such as lymphocyte infiltration, necrosis and excessive fibrous tissue growths.
Immediate breast reconstruction with a saline implant and AlloDerm, following removal of a Phyllodes tumor
Shirley A Crenshaw, Michael D Roller, Jeffery K Chapman
World Journal of Surgical Oncology , 2011, DOI: 10.1186/1477-7819-9-34
Abstract: A 22-year-old woman presented with a 4 cm mass in the left breast upon initial examination. Although the initial needle biopsy report indicated a fibroadenoma, the final pathologic report revealed a 6.5 cm × 6.4 cm × 6.4 cm benign phyllodes tumor ex vivo. Treatment was a simple nipple-sparing mastectomy coupled with immediate breast reconstruction. After the mastectomy, a subpectoral pocket was created for a saline implant and AlloDerm was stitched to the pectoralis and serratus muscle in the lower-pole of the breast.Saline implant with AlloDerm can be used for immediate breast reconstruction post-mastectomy for treatment of a phyllodes tumor.Cystosarcoma phyllodes was first described in 1838 by Johannes Müller but was not found to be malignant until 1943 by Cooper and Ackerman [1]. It is now commonly called phyllodes tumor. It is less than 1% of breast tumors and exhibits unpredictable behaviour.Reports in literature have been focused on surgical approaches to the tumor removal. Although patient assessment prior to tumor removal often includes plans for immediate breast reconstruction, these approaches are rarely reported unless the tumor is classified as giant or is in an adolescent female [2-5]. Usual tumor treatment is wide local excision and simple mastectomy [6-8]. However, there have been few reports on breast reconstruction with phyllodes tumors, especially within the last 10 years. Because of the fast growth rate of these tumors, a greater than a 1 cm negative margin is preferred with tumor removal and a mastectomy may have to be performed to prevent local reoccurrence. Breast reconstruction usually consists of a transverse rectus abdominis musculocutaneous (TRAM) flap or a latissimus dorsi (LD) musculocutaneous flap as in other breast cancers.Here we report a single surgery that includes reconstruction of the breast immediately post-mastectomy using a saline implant and AlloDerm. AlloDerm is becoming increasingly popular for immediate breast reconstruction
Tailoring of anodic surface layer properties on titanium and its implant alloys for biomedical purposes  [PDF]
E. Krasicka-Cydzik
Journal of Achievements in Materials and Manufacturing Engineering , 2010,
Abstract: and nanostructural titania and alloy component oxides. Evaluation of their properties for various biomedical applications in implantology and biosensing.Design/methodology/approach: Samples of titanium and its alloys were anodized in phosphoric acid solutions at different concentrations (0.5 ~ 4 M) with or without additions according to appropriate polarization regimes. Anodized samples were characterized by SED+EDS, electrochemical and impedance (EIS) tests and biocompability examination. Titanium and its alloys (Ti6Al4V and Ti6Al7Nb) samples were also used to form the nanostructural layer (nanotubes) by anodizing. The latter was used as a platform for glucose biosensing.Findings: Anodizing of titanium materials in phosphoric acid solutions allowed to obtain surface layers of various morphology and topography. They differ in porosity, thickness and chemical composition and according to their specific properties can be used in various biomedical applications. The development of gel-like layer and formation of nanotube layer was observed while anodizing in higher concentration of electrolyte or anodizing in the presence of fluorides. Both surface layers are much more bioactive than anodic barrier oxide layers on titanium. The primary tests to use nanostructured layer as platform for the third generation biosensors were promising.Practical implications: Use of medical implants covered with porous and nanostructural anodic layers tailored to particular biomedical purposes enables new practical applications in implantology and biosensing.Originality/value: Phosphate gel-like layer over surface oxide layer on titanium materials and nanostructural surface layer rich in both: phosphates and fluorides, are highly bioactive, which is the desirable property of implant materials.
Designing, preparing and evaluation of novel HA/Ti composite coating for endodontic dental implant
Fathi MH.,Mortazavi V.,Moosavi SB.
Journal of Dental Medicine , 2002,
Abstract: Nowadays, application of implants as a new method for replacing extracted teeth have been improved. So, many researches have been performed for improving the characteristics of implants. The aim of this study was to design and produce a desired coating in order to obtaining two goals including; improvement of the corrosion behavior of metallic endodontic implant and the bone osseointegration simultaneously. Stainless steel 316L (SS), cobalt-chromium alloy (Vit) and commercial pure titanium (cpTi) were chosen as metallic substrates and hydroxyapatite coating (HAC) were performed by plasma-spraying (PS) process on three different substrates. A novel double layer Hydroxyapatite/Titanium (HA/Ti) composite coating composed of a HA top layer and a Ti under layer was prepared using PS and physical vapor deposition (PVD) process respectively on SS. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure, morpholgy and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens behavior as an indication of biocmpatibility. Results indicated that the cpTi possesses the highest and SS the lowest corrosion resistance (highest corrosion current density) between uncoated substrates. This trend was independent to the type of physiological environment. The HA coating decreased the corrosion current density of HA coated metallic implants but did not change that trend. HAC acted as a mechanical barrier on the metallic substrate but could not prevent the interaction between metallic substrate and environment completely. The HA/Ti composite coating improved the corrosion behavior of SS. The corrosion current density of HA/Ti coated SS decreased and was exactly similar to single HA coated cpTi in physiological solutions. The results indicated that HA/Ti composite coated SS could be used as an endodontic implant and two goals including improvement of corrosion resistance (biocompatibiiity) and bone osseointegration could be obtained simultaneously.
Progress in Research on the Surface/Interface of Materials for Hard Tissue Implant
LIU Xuan-Yong
无机材料学报 , 2010, DOI: 10.3724/sp.j.1077.2011.00001
Abstract: The investigation of the surface/interface of hard tissue implant materials is very important for improving their properties and application. This paper reviews the research progress and tendency of studies on the surface/interface for hard tissue implant, especially on titanium and titanium alloys, based on the law of hard tissue implant. The improvement of the bone regeneration and antibacterial properties of titanium―based alloys by surface modification has become the hot topics in recent years. Generally, loading growth factors and coating bioactive ceramics onto the surfaces of titanium and its alloys are valid ways to improve their ability of bone regeneration. And loading antibiotics and antibacterial agents have been proven to be an effective method to improve the antibacterial property of titanium implant. With the development of nanotechnology and biotechnology as well as the innovation of surface modification technologies, it is expected that to obtain titanium implants with combining bone regeneration and antibacterial properties by the hybrid surface modification.
Implant-retained craniofacial prostheses for facial defects
Federspil, Philipp A.
GMS Current Topics in Otorhinolaryngology, Head and Neck Surgery , 2009,
Abstract: Craniofacial prostheses, also known as epistheses, are artificial substitutes for facial defects. The breakthrough for rehabilitation of facial defects with implant-retained prostheses came with the development of the modern silicones and bone anchorage. Following the discovery of the osseointegration of titanium in the 1950s, dental implants have been made of titanium in the 1960s. In 1977, the first extraoral titanium implant was inserted in a patient. Later, various solitary extraoral implant systems were developed. Grouped implant systems have also been developed which may be placed more reliably in areas with low bone presentation, as in the nasal and orbital region, or the ideally pneumatised mastoid process. Today, even large facial prostheses may be securely retained. The classical atraumatic surgical technique has remained an unchanged prerequisite for successful implantation of any system. This review outlines the basic principles of osseointegration as well as the main features of extraoral implantology.
CREEP BEHAVIORS OF Mg MICROALLOYED WROUGHT SUPERALLOYS
MA Peili YUAN Ying ZHONG Zengyong Central Iron,Steel Research Institute,Ministry of Metallurgical Industry,Beijing,China MA Peili Senior Engineer,Labof Superalloy,Central Iron,Steel Research Institute,Ministry of Metallurgical Industry,Beijing,China,
MA Peili YUAN Ying ZHONG Zengyong Central Iron and Steel Research Institute
,Ministry of Metallurgical Industry,Beijing,China MA Peili Senior Engineer,Lab.of Superalloy,Central Iron and Steel Research Institute,Ministry of Metallurgical Industry,Beijing,China

金属学报(英文版) , 1990,
Abstract: By adding small amount of Mg to the wrought superalloys,the steady stage of creep,and es- pecially the tertiary stage of creep are prolonged.Also,the steady creep rate is decreased within the range of low strain rates.At higher strain rates,however,the effect of Mg on creep rate vanishes.This may be attributed to the Mg dissolution in the matrix.A mechanism of the effects of Mg addition on creep behaviors is proposed.
CORROSION OF MOLYBDENUM IN AQUEOUS SOLUTIONS
Mo在水溶液中的耐腐蚀性能

YI Danqing,CAO Yu,LIU Sha,
易丹青
,曹昱,刘沙

腐蚀科学与防护技术 , 2003,
Abstract: Molybdenum is an important engineering metal and has been widely used in electronic,metallurgical,chemical and glass industries.As far as corrosion properties of Mo are concerned,they are so complex that there is no clear theoretical picture yet.The electrochemical behavior of Mo has been extensively studied.The date given in literature and interpretation of results obtained exhibit a large variability.An overview of studies related to electrochemical and galvanic corrosion behavior of molybdenum is presented in this article.Meanwhile,corrosion resistance of molybdenum in various aqueous solutions,such as alkaline solution,acids,inorganic salt solutions and seawater are discussed from technique point of view.
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