Extraction and Chemistry of Rubber Allergens
Robert N. Phalen, Howard I. Maibach in Protective Gloves for Occupational Use, 2023
The problem of ZDTC reacting with metal components of a chromatography system can be potentially overcome by using an instrument in which the entire sample flow path, including the injection loop, all tubing, and the analytical column, has been lined with polyether ether ketone (PEEK).33,40 Using a PEEK-lined HPLC, ZDTCs and MBT were monitored at 280 and 325 nm, respectively. Zinc sulfate was added to the mobile phase to compete with any free residual metals for binding to ZDTCs. Bergendorff et al.33 reported the presence of ZDEC, zinc pentamethylenedithiocarbamate (ZPD), ZDBC, and MBT from latex and nitrile glove acetone extracts. Several of these gloves contained multiple accelerators. The ZDEC detection limit was reported to be 1 µg/mL. No thiurams were found in any of the 19 gloves analyzed.
Biological behavior of titanium, zirconia or PEEK dental implant-abutments
J. Belinha, R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, João Manuel, R.S. Tavares in Biodental Engineering V, 2019
The literature shows that titanium (Ti) is the most widely used material for implant-abutments, then has become the “gold-standard” in oral implantology due to its excellent mechanical properties and biocompatibility (Gómez-Florit et al. 2014). For a long time and even actually, metallic abutments were considered the best option for customized prosthetic solutions. However, the grey color might impair the esthetics. Hence, different materials that are pure white in color should adequately simulate the color of natural teeth (Linkevicius et al. 2015). In the last decades, zirconia (Zr) has emerged in the prosthetic field as a promising esthetic biomaterial with mechanical properties similar or ever higher when compared to titanium. Polyetheretherketone (PEEK) is a polymer that has been extensively studied in biomedicine for implantation of lost tissues, specifically bone. PEEK is not yet used as prosthetic abutments, despite of being applied for dental implants, provisional prostheses, healing abutments or impressing transfers. Therefore, the purpose of this review was to explore the existing literature of biological behaviors of different abutment materials, specifically titanium, zirconia, and polyetheretherketone (PEEK) (Figure 1).
Additive Manufacturing (3D Printing) in Brachytherapy
William Y. Song, Kari Tanderup, Bradley R. Pieters in Emerging Technologies in Brachytherapy, 2017
Two examples of such materials or composite resins would be polyether ether ketone (PEEK) which up until recently was only available for large-scale industrial SLS AM machines. However, only in 2015, PEEK filament been introduced to the desktop printer category utilizing the FDM process. PEEK can be repeat steam sterilized opening up the possibility of repeat-use applicators, templates, and guides that are MR- and bio-compatible. Another USP class V1 AM material is Accura® ClearVue™ (3D Systems Inc., SC, USA). Accura® ClearVue™ is a rigid, non-metallic, clear (post curing) plastic with a density of 1.17 g/cm3 that can be steam sterilized to (USP) class V1 guidelines.
Device profile of the FlareHawk interbody fusion system, an endplate-conforming multi-planar expandable lumbar interbody fusion cage
Published in Expert Review of Medical Devices, 2023
Peter B. Derman, Rachelle Yusufbekov, Brian Braaksma
Interbody fusion devices vary not only in geometry but also in composition. The various materials have different intrinsic properties with implications on device performance. The modulus of elasticity is a measure of the stiffness of a material. If the stiffness of the device exceeds that of the surrounding bone, there is a higher risk of subsidence and its associated complications [6]. Historically interbody devices have been manufactured from titanium or polyetheretherketone (PEEK). The modulus of elasticity of PEEK more closely matches that of bone than that of solid titanium [7]. PEEK also features superior imaging characteristics on post-operative imaging, allowing for improved assessment of fusion compared to traditional titanium. However, roughened titanium has been shown to exhibit mechanical and biological advantages over smooth surfaces [8]. While many devices are made of a single material, some devices combine multiple materials (e.g. PEEK and titanium) in an effort to exploit positive attributes of each.
Study and numerical analysis of Von Mises stress of a new tumor-type distal femoral prosthesis comprising a peek composite reinforced with carbon fibers: finite element analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Carbon-fiber-reinforced polyetheretherketone (CF-PEEK) has been successfully applied in orthopedics due to its superior abrasion resistance compared to ultra-high-molecular-weight polyethylene (UHMWPE) (Giurea et al. 2014), its excellent light transmission (Uri et al. 2020), and the fact that implants composed of CF-PEEK are lighter than those based on metal materials (Koh et al. 2019). These advantages render CF-PEEK a promising orthopedic implant material. Moreover, its elastic modulus is relatively compatible with that of human bones, which can effectively avoid the ‘stress shielding’ effect, thereby avoiding secondary fractures, bone loss, and osteolysis (Bryan et al. 1996; Golish and Mihalko 2011; Nakahara et al. 2013; Li et al. 2015). Excellent light transmission properties are also extremely important in orthopedics, especially in the field of bone oncology. By eliminating the interference of metal artifacts, this property can help doctors detect and identify early tumor recurrence, and orthopedic surgeons can determine the appropriate radiotherapy dose more accurately after resolving the issue of ray refraction. Radiation damage to surrounding tissues can also be avoided. Moreover, the emergence of macromolecular implant materials also provides a good alternative to solve the issues related to metal ion release during the wear process of metal prostheses (Scholes and Unsworth 2007).
The relative influence of model parameters on finite element analysis simulations of intervertebral body fusion device static compression performance
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Andrew P. Baumann, Meng-Ting Hsieh, Anton E. Dmitriev, Jeffrey C. Lotz
This study investigated the influence of three general parameters: IBFD geometry, IBFD material model, and boundary conditions. These parameters were chosen and implemented to replicate the range of model inputs observed in the previous 510(k) review. IBFD geometry was obtained from the ASTM Interlaboratory Study #1588. This consisted of a family of three IBFDs designed to have low, medium, and high strength (Figure 1). IBFD material properties were based on polyether ether ketone (PEEK, Young’s Modulus = 4.0 GPa, Poisson’s Ratio = 0.38) (Kurtz and Devine 2007; Panayotov et al. 2016). The constitutive models included linear elasticity and a bi-linear elastic plastic model with von Mises yielding. All models were implemented with isotropic and homogenous material properties. Boundary conditions varied from kinematic conditions that applied displacements directly to the superior and inferior surfaces of the IBFDs, rigid surfaces which replicated load fixture platens, and load fixture platens with pocket geometry. All boundary condition scenarios replicated static compression under displacement control with a minimum of 1.2 mm of applied compression. The model parameters were varied to produce a total of 13 different simulation scenarios (Figure 2, Table 1). Coupled with the three IBFD geometries, this produced a total of 39 unique simulations.
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