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Implant passivity

Wenguang Li
Strain energy-based constitutive laws with damage effect were proposed by using existing both uniaxial tensile test and tubular biaxial inflation test data on the human great saphenous vein (GSV) segments. These laws were applied into GSV coronary artery bypass grafts (CABG) by employing a thin-walled vessel model to evaluate their passive biomechanical performance under coronary artery physiological conditions at a fixed axial pre-stretch. At a peak systolic pressure in 100-150 mmHg, a 20-33% GSV diameter dilation was predicted with the law based on tubular biaxial inflation test data and agreed well with 25% dilation in clinical observation in comparison with as small as 2-4% dilation estimated with the law based on uniaxial tensile test data...
February 23, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Lorenzo Vannozzi, Veronica Iacovacci, Arianna Menciassi, Leonardo Ricotti
INTRODUCTION: Traditional drug release systems normally rely on a passive delivery of therapeutic compounds, which can be partially programmed, prior to injection or implantation, through variations in the material composition. With this strategy, the drug release kinetics cannot be remotely modified and thus adapted to changing therapeutic needs. To overcome this issue, drug delivery systems able to respond to external stimuli are highly desirable, as they allow a high level of temporal and spatial control over drug release kinetics, in an operator-dependent fashion...
March 9, 2018: Expert Opinion on Drug Delivery
Paolo Pesce, Francesco Pera, Paolo Setti, Maria Menini
PURPOSE: To evaluate the accuracy and precision of a digital scanner used to scan four implants positioned according to an immediate loading implant protocol and to assess the accuracy of an aluminum framework fabricated from a digital impression. MATERIALS AND METHODS: Five master casts reproducing different edentulous maxillae with four tilted implants were used. Four scan bodies were screwed onto the low-profile abutments, and a digital intraoral scanner was used to perform five digital impressions of each master cast...
March 2018: International Journal of Prosthodontics
Gabriele Dell'Era, Matteo Ziacchi, Eleonora Prenna, Igor Diemberger, Marco Varalda, Cristian Martignani, Federico Guerra, Mauro Biffi, Eraldo Occhetta
BACKGROUND: The management of patients explanted for implantable defibrillator (ICD) infections may be complex when anti-bradycardia pacing and tachyarrhythmia protection are needed. We aimed to test the efficacy and safety of a conventional ICD externally connected to a transvenous dual-coil lead as bridging therapy before the re-implantation. METHODS AND RESULTS: We enrolled seven patients explanted for ICD infections and needing prolonged antibiotic therapy in two high-volume hospitals in Italy and treated them with a passive can external ICD for a mean of 13 (4-30) days before re-implant...
March 8, 2018: Pacing and Clinical Electrophysiology: PACE
M Lenzhofer, M Hohensinn, C Strohmaier, H A Reitsamer
Minimally invasive glaucoma surgery (MIGS) has been developed for all drainage pathways in glaucoma treatment. Besides implants overriding the resistance in the trabecular meshwork (iStent®, iStent Inject® [both Glaukos Germany GmbH, Wiesbaden, Germany], Hydrus Microstent® [Ivantis, Irvine, CA, USA]) and draining to the suprachoroidal space (Cypass Micro Stent® [Alcon Laboratories, Inc., Fort Worth, TX, USA], iStent Supra® [Glaukos Germany GmbH]), surgeons can further drain aqueous humor into the subconjunctival space with a transscleral MIGS implant (XEN45® [Allergan Plc...
March 2, 2018: Der Ophthalmologe: Zeitschrift der Deutschen Ophthalmologischen Gesellschaft
Sung-Hyun Lee, Sung-Hyun Noh, Keun-Churl Chun, Joung-Kyue Han, Churl-Hong Chun
BACKGROUND: We report the successful use of allograft-prosthesis composite (APC) and structural femoral head allografting in the bilateral reconstruction of large femoral and tibial uncontained defects during revision total knee arthroplasty (RTKA). CASE PRESENTATION: A 67-year-old female with degenerative arthritis underwent bilateral total knee arthroplasty (TKA) using the Press Fit Condylar (PFC) modular knee system at our clinic in March, 1996. At 8 years postoperatively, the patient presented with painful, bilateral varus knees, with swelling, limited passive range of motion (ROM), and severe instability...
March 2, 2018: BMC Musculoskeletal Disorders
Tiziano Testori, Tommaso Weinstein, Fabio Scutellà, Hom-Lay Wang, Giovanni Zucchelli
Patient expectations from implant treatment have changed over the years and esthetics plays an important role in defining what is now called success of rehabilitation. Of the many factors that influence the outcome of the rehabilitation, the two main ones are the bone and soft-tissue deficiencies at the intended implant site. Many surgical approaches are described in terms of timing of implant placement and management of regenerative procedures. The aim of this article is to discuss the different implant placement alternatives in the esthetic area, in particular: (i) the timing of implant placement/regenerative procedures/skeletal growth/altered passive eruption; (ii) the correct three-dimensional position of the fixture between the cuspids and in the premolar area; (iii) multiple missing teeth in the esthetic area with single tooth/pontic or cantilevered options/prosthetic compensation; (iv) placement of implants into infected sites; and (v) the influence of abutment and crown morphology on implant position...
February 27, 2018: Periodontology 2000
Andrea Coluccio, Gabriela Ecco, Julien Duc, Sandra Offner, Priscilla Turelli, Didier Trono
BACKGROUND: The KZFP/KAP1 (KRAB zinc finger proteins/KRAB-associated protein 1) system plays a central role in repressing transposable elements (TEs) and maintaining parent-of-origin DNA methylation at imprinting control regions (ICRs) during the wave of genome-wide reprogramming that precedes implantation. In naïve murine embryonic stem cells (mESCs), the genome is maintained highly hypomethylated by a combination of TET-mediated active demethylation and lack of de novo methylation, yet KAP1 is tethered by sequence-specific KZFPs to ICRs and TEs where it recruits histone and DNA methyltransferases to impose heterochromatin formation and DNA methylation...
February 26, 2018: Epigenetics & Chromatin
Yifei Dai, Michael B Cross, Laurent D Angibaud, Cyril Hamad, Amaury Jung, Jean-Yves Jenny
PURPOSE: Posterior tibial slope (PTS) for cruciate-retaining (CR) total knee arthroplasty (TKA) is usually pre-determined by the surgeon. Limited information is available comparing different choices of PTS on the kinematics of the CR TKA, independent of the balancing of the extension gap. This study hypothesized that with the same balanced extension gap, the choice of PTS significantly impacts the intraoperatively measured kinematics of CR TKA. METHODS: Navigated CR TKAs were performed on seven fresh-frozen cadavers with healthy knees and intact posterior cruciate ligament (PCL)...
February 23, 2018: Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA
Burak Yilmaz, Faris A Alshahrani, Ediz Kale, William M Johnston
STATEMENT OF PROBLEM: Veneering with porcelain may adversely affect the marginal fit of long-span computer-aided design and computer-aided manufacturing (CAD-CAM) implant-supported fixed prostheses. Moreover, data regarding the precision of fit of CAD-CAM-fabricated implant-supported complete zirconia fixed dental prostheses (FDPs) before and after porcelain layering are limited. PURPOSE: The purpose of this in vitro study was to evaluate the effect of porcelain layering on the marginal fit of CAD-CAM-fabricated complete-arch implant-supported, screw-retained FDPs with presintered zirconia frameworks compared with titanium...
February 6, 2018: Journal of Prosthetic Dentistry
Zheng Wei, Jonathan Edin, Anna Emelie Karlsson, Katarina Petrovic, Inna L Soroka, Inger Odnevall Wallinder, Yolanda Hedberg
The extent of metal release from implant materials that are irradiated during radiotherapy may be influenced by irradiation-formed radicals. The influence of gamma irradiation, with a total dose of relevance for radiotherapy (e.g., for cancer treatments) on the extent of metal release from biomedical stainless steel AISI 316L and a cobalt-chromium alloy (CoCrMo) was investigated in physiological relevant solutions (phosphate buffered saline with and without 10 g/L bovine serum albumin) at pH 7.3. Directly after irradiation, the released amounts of metals were significantly higher for irradiated CoCrMo as compared to nonirradiated CoCrMo, resulting in an increased surface passivation (enhanced passive conditions) that hindered further release...
February 9, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Jianfang Li, Xiaojing He, Guannan Zhang, Ruiqiang Hang, Xiaobo Huang, Bin Tang, Xiangyu Zhang
Ti-6Al-4V (TC4) has received increasing attention as biomaterial but also raised concerns about the long-term safety of releasing of metal ions and poor wear resistance. In this work, an ZrO2/TiO2 alloyed layer was prepared on TC4 by plasma surface alloying with Zr and subsequently annealed in the air for improved corrosion and wear resistant. To assess the corrosion performance of the alloyed layer, the specimens were measured by open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization in simulated body fluid solution...
January 29, 2018: Bioelectrochemistry
W J Nie, Y X Zhang, H H Yu, R Li, R Y He, N N Dong, J Wang, R Hübner, R Böttger, S Q Zhou, H Amekura, F Chen
We report on the synthesis of embedded gold (Au) nanoparticles (NPs) in Nd:YAG single crystals using ion implantation and subsequent thermal annealing. Both linear and nonlinear absorption of the Nd:YAG crystals have been enhanced significantly due to the embedded Au NPs, which is induced by the surface plasmon resonance (SPR) effect in the visible light wavelength band. Particularly, through a typical Z-scan system excited by a femtosecond laser at 515 nm within the SPR band, the nonlinear absorption coefficients of crystals with Au NPs have been observed to be nearly 5 orders of magnitude larger than that without Au NPs...
February 7, 2018: Nanoscale
David Peñarrocha-Oltra, Blanca Serra-Pastor, José-Carlos Balaguer-Martí, Miguel Peñarrocha-Diago, Rubén Agustín-Panadero
Background: Immediate loading protocols for the rehabilitation of edentulous or partially edentulous patients have become very popular, due to the conveniences they afford in comparison with conventional loading techniques. Material and Methods: A preliminary study was carried out with 8 patients subjected to dental implant treatment with an immediate loading protocol involving a novel system of abutments with flexible screws. Implant survival was analyzed, together with marginal bone loss and patient and dentist satisfaction...
December 2017: Journal of Clinical and Experimental Dentistry
David M Saylor, Brent A Craven, Vaishnavi Chandrasekar, David D Simon, Ronald P Brown, Eric M Sussman
Many cardiovascular device alloys contain nickel, which if released in sufficient quantities, can lead to adverse health effects. However, in-vivo nickel release from implanted devices and subsequent biodistribution of nickel ions to local tissues and systemic circulation are not well understood. To address this uncertainty, we have developed a multi-scale (material, tissue, and system) biokinetic model. The model links nickel release from an implanted cardiovascular device to concentrations in peri-implant tissue, as well as in serum and urine, which can be readily monitored...
February 13, 2018: Acta Biomaterialia
Paul Glogener, Michael Krause, Jens Katzer, Markus A Schubert, Mario Birkholz, Olaf Bellmann, Claudia Kröger-Koch, Harald M Hammon, Cornelia C Metges, Christine Welsch, Roman Ruff, Klaus P Hoffmann
A microelectronic biosensor was subjected to in vivo exposure by implanting it in the vicinity of m. trapezii (Trapezius muscle) from cattle. The implant is intended for the continuous monitoring of glucose levels, and the study aimed at evaluating the biostability of exposed semiconductor surfaces. The sensor chip was a microelectromechanical system (MEMS) prepared using 0.25 µm complementary metal-oxide-semiconductor CMOS/BiCMOS technology. Sensing is based on the principle of affinity viscometry with a sensoric assay, which is separated by a semipermeable membrane from the tissue...
February 1, 2018: Biosensors
Kimberly D Brewer, Genevieve M Weir, Iulia Dude, Christa Davis, Cathryn Parsons, Andrea Penwell, Rajkannan Rajagopalan, Leeladhar Sammatur, Chris V Bowen, Marianne M Stanford
BACKGROUND: Oil emulsions are commonly used as vaccine delivery platforms to facilitate slow release of antigen by forming a depot at the injection site. Antigen is trapped in the aqueous phase and as the emulsion degrades in vivo the antigen is passively released. DepoVax™ is a unique oil based delivery system that directly suspends the vaccine components in the oil diluent that forces immune cells to actively take up components from the formulation in the absence of passive release...
January 27, 2018: Journal of Biomedical Science
Afroz S Mohammad, Jessica I Griffith, Chris E Adkins, Neal Shah, Emily Sechrest, Emma L Dolan, Tori B Terrell-Hall, Bart S Hendriks, Helen Lee, Paul R Lockman
PURPOSE: The blood-tumor barrier (BTB) limits irinotecan distribution in tumors of the central nervous system. However, given that the BTB has increased passive permeability we hypothesize that liposomal irinotecan would improve local exposure of irinotecan and its active metabolite SN-38 in brain metastases relative to conventional irinotecan due to enhanced-permeation and retention (EPR) effect. METHODS: Female nude mice were intracardially or intracranially implanted with human brain seeking breast cancer cells (brain metastases of breast cancer model)...
January 9, 2018: Pharmaceutical Research
Kiyotaka Fukamachi, Jamshid H Karimov, David J Horvath, Gengo Sunagawa, Nicole A Byram, Barry D Kuban, Nader Moazami
OBJECTIVES: Mechanical circulatory support has become standard therapy for adult patients with end-stage heart failure; however, in paediatric patients with congenital heart disease, the options for chronic mechanical circulatory support are limited to paracorporeal devices or off-label use of devices intended for implantation in adults. Congenital heart disease and cardiomyopathy often involve both the left and right ventricles; in such cases, heart transplantation, a biventricular assist device or a total artificial heart is needed to adequately sustain both pulmonary and systemic circulations...
January 19, 2018: Interactive Cardiovascular and Thoracic Surgery
Ana Mellado-Valero, Anna Igual Muñoz, Virginia Guiñón Pina, Ma Fernanda Sola-Ruiz
The aim of the present study is to analyze the electrochemical behavior of five different dental alloys: two cobalt-chromium alloys (CoCr and CoCr-c), one nickel-chromium-titanium alloy (NiCrTi), one gold-palladium alloy (Au), and one titanium alloy (Ti6Al4V), and the galvanic effect when they are coupled to titanium implants (TiG2). It was carried out by electrochemical techniques (open circuit measurements, potentiodynamic curves and Zero-Resistance Ammetry) in artificial saliva (AS), with and without fluorides in different acidic conditions...
January 22, 2018: Materials
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