BACKGROUND The pathogenesis of total joint replacement failure is multifactorial. One hypothesis suggests that corrosion and wear of alloys result in metal ion release, which may then cause sensitization and even implant failure, owing to the acquired immune reactivity. OBJECTIVES To assess cobalt, nickel and chromium(VI) release from, and the metal composition of, failed metal-on-ethylene to...

BACKGROUND In Brazil, despite the recommendations of the Brazilian Society of Hemodynamics and Interventional Cardiology, the National Health System has not yet approved the use of drug-eluting stents. In percutaneous coronary interventions performed in the public and part of the private health care system, bare metal stents are used as the only option. Therefore, new information on bare metal ...

Eight retrieved metal-on-metal total hip replacements displayed corrosion damage along the cobalt-chromium alloy liner taper junction with the Ti alloy acetabular shell. Scanning electron microscopy indicated the primary mechanism of corrosion to be grain boundary and associated crevice corrosion, which was likely accelerated through mechanical micromotion and galvanic corrosion resulting from ...

A microstructural study was conducted on 15 cobalt-chromium-nickel alloys of the basic composition 40 Co-30 Ni-30 Cr. The alloys were strengthened by the addition of tantalum and tantalum-rich regions were found at the interdendritic spaces. The increase in Ta concentration caused a decrease in the concentration of the a phase and an increase in the amounts of the a phase. Excessive amounts of ...

The clinical and metallurigical characteristics of five cast cobalt-chromium-molybdenum alloy femoral hip prostheses which failed in vivo were evaluated. The devices included: two of the Howmedica Muller-Charnley design, two of the Howmedica Charnley design, and one of the Zimmer Aufranc-Turner design. Fractographic analyses demonstrated that the five devices had failed by fatigue which origina...

Extended x-ray absorption fine structure ~EXAFS! measurements of Co78Cr22 , Co86Cr12Ta2 , and Co86Cr12Pt2 films were made to investigate the local structure and chemistry around Ta and Pt atoms to determine their site distributions in these alloys. Comparisons between the measured data and data collected from experimental standards and calculated using theoretical EXAFS simulation codes indicat...

Background: Orthodontics is a part of dentistry that includes preventive methods and correction of dental irregularities that need to be repositioned by functional and mechanical tools to provide an ideal occlusion and a beautiful face for patients. There are currently four metal arch wires used in orthodontic treatment: stainless steel alloy, cobalt-chromium alloy, nickel-titanium alloy, and b...

OBJECTIVES A nondestructive, rapid, and practical method of dental alloy sorting is desirable. In this study, the hypothesis to be tested is that dental alloys show significantly different and high thermoelectric power values, on the basis of which alloy sorting is possible. METHODS Six silver-colored commercial dental casting alloys are used in this study: two silver alloys, one gold-silver-...