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Dental implants are mostly fabricated of titanium. Potential problems associated with these implants are discussed in the literature, for example, overloading of the jawbone during mastication due to the significant difference in the elastic moduli of titanium (110 GPa) and bone (≈1-30 GPa). Therefore poly-ether-ether-ketone (PEEK) could represent an alternative biomaterial (elastic modulus 3-4 GPa). Endolign(®) represents an implantable carbon fiber reinforced (CFR)-PEEK including parallel oriented endless carbon fibers. According to the manufacturer it has an elastic modulus of 150 GPa. PEEK compounds filled with powders show an elastic modulus around 4 GPa. The aim of the present finite element analysis was to point out the differences in the biomechanical behavior of a dental implant of Endolign(®) and a commercial powder-filled PEEK. Titanium served as control. These three materials were used for a platform-switched dental implant-abutment assembly, whereas Type 1 completely consisted of titanium, Type 2 of a powder-filled PEEK and Type 3 of Endolign(®). A force of 100 N was applied vertically and of 30° to the implant axis. All types showed a minimum safety factor regarding the yield strength of cortical bone. However, within the limits of this study the Type 2 implant showed higher stresses within the adjacent cortical bone than Type 1 and Type 3. These implant assemblies showed similar stress distributions. Endless carbon fibers give PEEK a high stability. Further investigations are necessary to evaluate whether there is a distinct amount of endless carbon fibers causing an optimal stress distribution behavior of CFR-PEEK.
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http://dx.doi.org/10.1016/j.jbiomech.2014.11.017 | DOI Listing |
J Chem Phys
September 2025
Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain.
The mechanical properties of graphene are investigated using classical molecular dynamics simulations as a function of temperature T and external stress τ. The elastic response is characterized by calculating elastic constants via three complementary methods: (i) numerical derivatives of stress-strain curves, (ii) analysis of cell fluctuation correlations, and (iii) phonon dispersion analysis. Simulations were performed with two interatomic models: an empirical potential and a tight-binding electronic Hamiltonian.
View Article and Find Full Text PDFACS Omega
September 2025
Materials and Manufacturing Directorate, AFRL/RXEE, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States.
This study addresses a critical limitation in direct bonded copper (DBC) materials used in power electronics by introducing a copper-zirconium (Cu/Zr) alloy interposing layer at the copper-ceramic interface. This novel design aims to mitigate mechanical stress induced by mismatched material properties, such as the coefficient of thermal expansion (CTE) and elastic modulus, during thermal cycling. The key findings of this study are (1) thermal fatigue improvement: Test samples with the Cu/Zr interface layer (Cu-Cu/Zr-AlN) three times enhanced thermal fatigue resistance, surviving 30 thermal cycles from -55 to 300 °C before delamination, while standard DBC substrates without the Cu/Zr layer failed after just 10 cycles, indicating a performance improvement with the Cu/Zr alloy, (2) durability projections: Based on the Coffin-Manson model, if the upper temperature is capped at 150 °C, the Cu-Cu/Zr-AlN substrates are projected to survive approximately 1372 cycles, underscoring their potential for long-term reliability, and (3) stress mitigation: The Cu/Zr alloy layer bridges the CTE disparity between copper and ceramic, reducing mechanical stress and improving structural integrity across a broad temperature range (-55 to 300 °C).
View Article and Find Full Text PDFBiomed Eng Lett
September 2025
Department of Mechanical Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154 USA.
Alginate is known to readily aggregate and form a physical gel when exposed to cations, making it a promising material for bioprinting applications. Alginate and its derivatives exhibit viscoelastic behavior due to the combination of solid and fluid components, necessitating the characterization of both elastic and viscous properties. However, a comprehensive investigation into the time-dependent viscoelastic properties of alginate hydrogels specifically optimized for bioprinting is still lacking.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
August 2025
School of Mechanical Engineering, Jiangsu Key Laboratory for Design and Manufacturing of Precision Medicine Equipment, Southeast University, Nanjing, 211189, China. Electronic address:
Poly(L-lactic acid) (PLLA), as a substrate material, has been widely utilized in the field of biodegradable vascular stents. Prior to implantation, it is particularly crucial for these devices to assess the relationship of the mechanical properties and microstructures during full degradation cycle. Although previous studies have primarily focused on structural parameters such as crystallinity and molecular weight, there are relatively few reports that explore the impact of microstructure on mechanical performance from the perspective of chain configuration during the degradation.
View Article and Find Full Text PDFInt J Biol Macromol
September 2025
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, PR China. Electronic address:
Due to the poor regeneration ability of cartilage tissue, the design and fabrication of permanent hydrogel cartilage scaffolds with mechanical properties matching is still an urgent challenge. In this study, we propose an "inner swelling-outer restraint" strategy to construct Janus hydrogel for pressure-bearing cartilage replacement, which is inspired by the "Lamina-splendens" structure of cartilage. As a proof of concept, the poly(vinyl alcohol)/carboxymethyl cellulose sodium (PVA/CMCNa) layer is designed to capture more fluid by introducing negatively charged aggregates, while the macromolecular conformation of the PVA/MoS layer can be densified through wet annealing, thereby increasing the liquid permeation resistance of the PVA/CMCNa layer.
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