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Purpose: To evaluate the accuracy of complete-arch digital implant impressions using different intraoral scan body (ISB) materials and intraoral scanners (IOSs). Materials and Methods: The mandibular dental cast of an edentulous patient with six tissue-level dental implants was used as the master cast. Two types of ISBs--polyether ether ketone (PEEK) and plasma-coated medical titanium--were used with five IOSs: TRIOS 4 (T4), Virtuo Vivo (VV), Medit i700 (Mi700), iTero 5D (i5D), and Primescan (PS). To assess accuracy, digital impressions (n = 10) with each IOS and ISB were compared to two reference models obtained by digitizing the master cast with each ISB type using a desktop scanner (IScan4D LS3i) and importing the scan data into metrology software (Geomagic Control X). Root mean square (RMS) error was employed to evaluate overall deviation values (trueness), while precision was determined using the SD of RMS values. Statistical significance was set at P < .05. Kruskal-Wallis test was used, followed by the pairwise comparison method with Bonferroni correction (a = .05). Results: An interaction between ISB material and IOS was found (P = .001). Plasma-coated medical titanium ISBs demonstrated significantly higher trueness and precision compared to PEEK ISBs with T4 (P = .001), Mi700 (P = .001; P = .004), and i5D (P = .001). Conversely, VV exhibited higher trueness and precision values with PEEK ISBs (P = .005; P = .003). PS provided the highest trueness and precision regardless of the ISB material (P = .912). T4 showed the lowest accuracy for PEEK ISBs, and VV showed the lowest accuracy for plasma-coated medical titanium ISBs. Conclusions: Except for PS, all IOSs showed significant differences between ISB materials. PS demonstrated the highest accuracy with both ISB materials, whereas T4 had the lowest accuracy for PEEK ISBs, and VV showed the lowest accuracy for plasma-coated medical titanium ISBs. [ABSTRACT FROM AUTHOR]

Purpose: To assess the impact of fatigue loading on the internal and marginal fit of CAD/CAM-fabricated endocrowns for restoring endodontically treated molars using different machinable blocks. Materials and Methods: A total of 72 mandibular first molars were prepared using a standardized method and were divided into four groups (n = 18), each restored with a different CAD/CAM material: group V = polymerinfiltrated ceramic (Vita Enamic); group K = partially stabilized tetragonal zirconia (Katana); group E = lithium disilicate ceramic (IPS e.max CAD; and group B = polyetheretherketone (BioHPP). Endocrowns were subjected to thermomechanical fatigue loading. Internal and marginal adaptation of the endocrowns were examined at 66 points using the sectioning technique and a stereomicroscope. Data were analyzed using one-way ANOVA and Tukey post hoc test (a = .05). Results: Statistical tests showed that adhesive cementation resulted in significantly increased marginal and internal gap values in all regions in all four tested groups (P < .001). After thermomechanical fatigue loading, all regions in groups B and K showed a statistically significant difference, while no significant differences were found in the regions in group V (P > .05). In group E, the marginal (F = 71.00) and pulpal (F = 28.065) regions showed statistically significant differences (P < .001). Conclusion: Polymer-infiltrated ceramics showed the lowest gap even after thermomechanical fatigue loading and may therefore provide enhanced clinical survival of the restored tooth, favoring the use of this material for fabricating endocrown restorations. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the physical and mechanical behaviors of polyether ether ketone (PEEK) before and after thermocycling, as well as its potential use as a more durable prosthetic component for implantsupported and -retained removable dental prostheses (I-RDPs). Materials and Methods: Roughness and surface hardness were evaluated in specimens obtained using the subtractive method (n = 20) with a diameter of 9 mm and a thickness of 2 mm, and retention force was measured using attachments with a diameter of 4 mm and a height of 3 mm. For fatigue resistance testing, a polyurethane matrix with two ball abutment implants (MDL, Intra-Lock International) was used to simulate the mandibular alveolar ridge. A total of 40 attachments (n = 20 pairs) were placed in acrylic resin blocks using an analog technique for the direct clinical pickup of overdenture female attachments, then submitted to 2,900 insertion/removal cycles to simulate 24 months of overdenture use. Physical analyses were performed by Fouriertransform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and differential scanning calorimetry (DSC) before and after thermocycling (5°C to 55°C for 10,000 cycles). After normal distribution was verified by Shapiro-Wilk test, one-way ANOVA was applied to analyze the surface roughness and hardness, and two-way ANOVA with Bonferroni adjustment was used to assess the retention force (a = .05). Results: Thermocycling did not change the PEEK surface roughness or hardness (P > .05). As for the retention force, the highest average was observed after the thermocycling test (P = .006). Conclusion: Based on the FTIR, XRD, and DSC results, PEEK crystallinity decreased after thermocycling, and the physical and mechanical behaviors of this polymer were compatible with the proposed application, suggesting that PEEK is a component of greater durability for I-RDPs. [ABSTRACT FROM AUTHOR]

Highlights Carbon fiber fabrics reinforced polyether ether ketone (CFF/PEEK) composites show extraordinary mechanical properties which deeply relay on their interfacial properties. Herein, two simple desizing method of acetone and high‐temperature were used to remove sizing agent of CFF. The fiber surface roughness and surface activity increased after desizing, which enhances interfacial wettability between fiber and resin. The interface shear strength (IFSS) measured by micro‐bond test was used to evaluated the interfacial properties. After desizing, the IFSS enhanced from 41.7 to 51.2 MPa, which may be owing to enhanced of interfacial adhesion and mechanical locking between CFF and PEEK. CFF/PEEK laminates were fabricated by a simple film stacking method using hot‐pressing process of CFF and PEEK film. Interlaminar shear strength (ILSS) tested by short‐beam method increased from 62.5 to 71.3 MPa, and flexural strength increased from 754.4 to 805.5 MPa, which indicated the fiber‐matrix interface enhanced. Furthermore, forming quality and microscopic failure modes of CFF/PEEK verified fiber‐matrix interface enhanced after removing sizing agent. The interfacial and mechanical properties of CFF/PEEK composites significantly enhanced by using simple and effective desizing method. This study is expected to provide valuable insights into optimizing fiber surface treatments for enhancing durability and reliability of advanced composite materials. Acetone and high‐temperature desizing were used to remove sizing agent of CFF. The IFSS of treatment CFF increased over 25% compared with untreated ones. The ILSS and flexural strength of desizing‐CFF/PEEK enhanced notably. The fiber‐matrix interface between desizing‐CFF and PEEK resin enhanced. [ABSTRACT FROM AUTHOR]

Additive Manufacturing (AM) of carbon fiber reinforced polyetheretherketone (CF/PEEK) composites with excellent performance by Powder Bed Fusion (PBF) has great potential in the applications where high strength and high service temperature are required. However, the reinforcement mechanisms of CF/PEEK composites based on the PBF process are complex and show significant differences from traditional processing methods. In this paper, the mechanical properties of CF/PEEK prepared by PBF were investigated. The results showed that its X‐axis tensile strength and modulus were approximately equal to or a bit lower than the theoretical value with randomly distributed CF, but much lower than the theoretical value with unidirectional distribution of CF in composites. Meanwhile, mechanical strength anisotropy was observed. The composites' Y‐axis tensile strength was slightly lower than X‐axis, and the lowest strength existed in Z‐axis. To improve the weak Z‐axis strength, post‐processing of annealing and solvent‐induced crystallization were carried out, and the Z‐axis tensile strength of post‐processed parts reached 50 MPa, which was 62% higher than untreated samples. Consequently, suitable CF and proper post‐ processing for AM of high strength CF/PEEK were proposed, which would promote the industrial application of this technology. Highlights: The effect of CF on mechanical property of CF/PEEK prepared by PBF were studied.The optimal CF for PBF of high strength CF/PEEK were obtained.The post‐processing method for improving the Z‐axis strength were proposed.CF/PEEK with comprehensive mechanical property was successfully prepared by PBF. [ABSTRACT FROM AUTHOR]

Solidification models are key during simulation of several industrial processes involving thermoplastics. For simplicity, crystallinity is often not considered within these models, despite it being responsible for the phase transition. Several advanced methods, which consider crystallinity as the onset of solidification have been proposed in literature however, these have primarily been applied to classical homopolymers such as polypropylene (PP). The focus of this study is to develop a model that can capture the rheological response observed during the transition from liquid‐like to solid‐like behavior in injection molding grade polyetheretherketone (PEEK) due to crystallinity. Isothermal rheological experiments are performed alongside dynamic scanning calorimetry (DSC) characterization to correlate relative crystallinity to the apparent increase in viscosity. The model is extended to nonisothermal processes through the incorporation of the Nakamura model. Nonisothermal crystallization rheology experiments are performed and compared with a simulation of the oscillating rheometer process for validation. The modeled viscosity response and crystallization half‐time reproduced the experimental data with sufficient accuracy at low cooling rates, with an error of less than 5% up to cooling rates of 20°C min−1. This shows that the method is an accurate means of obtaining the rheological response during crystallization in a numerical simulation. [ABSTRACT FROM AUTHOR]

The main aim of bone tissue engineering is to develop novel scaffold structures that integrate biological functionality with sufficient mechanical strength and properties. In this study, bone scaffolds were fabricated using polyether ether ketone (PEEK) via 3D printing, resulting in three different porous designs. To enhance their biological attributes, these scaffolds were coated with an alginate and carbon nanotube (CNT) composite using a freeze-drying technique. The biological characteristics of fabricated samples, such as biocompatibility and bioactivity, were evaluated in simulated body fluid (SBF). Field emission scanning electron microscopy (FE-SEM) analysis showed that the 3D-printed PEEK scaffolds had a porous, uniform, and interconnected architecture with pore sizes between 321–378 µm. Energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) confirmed the formation of hydroxyapatite (HA) and bioactive calcium phosphate (Ca-P) on the scaffold surfaces, indicating their bioactivity. Cell biocompatibility was assessed using the MTT assay, which revealed a high cell viability rate of approximately 97% and no significant toxicity. Consequently, the 3D-printed PEEK scaffold coated with Alginate/0.3%wt CNT demonstrated promising microstructure, bioactivity, and biocompatibility, making it suitable for bone tissue regeneration. [ABSTRACT FROM AUTHOR]

Fouling mitigation provides many challenges in process equipment, especially in heat exchangers. In this work, the fouling behaviors of two polymers are compared to 1.4301 stainless steel (SS) in calcium sulfate solutions. An experimental setup that allows to classify the materials quickly and under varying process conditions is used to determine the fouling behavior. Results are compared to a screening apparatus which can test up to three materials simultaneously. Finally, the cleaning behavior of all three materials is investigated. Results show that polyether ether ketone (PEEK) is superior to SS in mitigating fouling and is easier to clean; however, polyether ether ketone with 30 % talcum (TKT) is not. This is attributed to the surface roughness of the materials. [ABSTRACT FROM AUTHOR]

Recent studies have indicated that the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is an ideal therapeutic target for osteoporosis because it affects the differentiation of osteoblasts and osteoclasts. RNA sequencing utilizing multifunctional graphene oxide (GO) nanosheets revealed a correlation between GO nanomaterials and the NLRP3 inflammasome, as well as osteogenic genes in macrophages. This study aimed to construct a bone microenvironment-responsive multifunctional two-dimensional GO coating on the surface of microporous sulfonated polyetheretherketone (SPEEK) via polydopamine modification (SPEEK@PDA-GO). In vitro analysis showed that the SPEEK@PDA-GO implants weakened the STAT3-mediated NLRP3/caspase-1/IL-1β signaling pathway in macrophages and subsequently prevented the formation of an extracellular inflammatory microenvironment, which is crucial for osteoclastogenesis. SPEEK@PDA-GO displayed significantly higher expression of M2 macrophage markers and osteogenic genes, indicating that the multifunctional GO nanosheets could facilitate bone regeneration via their immunomodulatory properties. The ability of SPEEK@PDA-GO to stimulate new bone formation and block bone loss caused by estrogen loss due to ovariectomy was also analyzed. The findings of this study offer valuable information on the possible involvement of the NLRP3 inflammasome in the interaction between the immune system and bone health in patients with osteoporosis. [Display omitted] • We developed SPEEK@PDA-GO to regulate immune-mediated bone homeostasis. • SPEEK@PDA-GO created a desirable osteoimmunomodulatory microenvironment. • SPEEK@PDA-GO inhibited the STAT3-mediated NLRP3/caspase-1/IL-1β axis in macrophages. • GO nanosheets restored the balance between osteogenesis and osteoclastogenesis. [ABSTRACT FROM AUTHOR]

Facial asymmetry is defined as a bilateral difference between facial components. Correction, often desired by the patient, can be performed with the aim of bone born patient-specific solid implants designed using 3D CAD software. This treatment is embedded in the daily practice of today's healthcare. However, an analysis of the implant's accuracy of placement has not been reported. This case series describes the accuracy analysis of bone born aesthetic facial implants manufactured out of polyether-ether-ketone (PEEK). The accuracy analysis was based on postoperative (cone beam) computed tomography ((CB)CT) data and preoperative 3D planning. The analysis showed a median entry point error of 0.7 mm (min: 0.1, max: 3.3, interquartile range: 0.78). The median maximal orientation error was 5.5° (min: 0.1, max: 36.8, interquartile range: 7.13). Both parameters showed an excellent intraobserver and interobserver agreement with an ICC above 0.84. The described cases show that the analysis method is an objective approach for determining the accuracy of PSI placement and indicates that these implants can be placed accurately on the osseous face. [ABSTRACT FROM AUTHOR]

In this study, we investigated the mechanical and tribological properties of the layer-by-layer structure of additively manufactured implant-grade Polyether Ether Ketone (PEEK) through the Material Extrusion (ME) process as a potential substitute for artificial joints. The effective elasticity modulus of the anisotropic 3D-printed PEEK was determined to be 2.505 GPa along the vertical and horizontal build orientations. The lubricated friction and wear performance were assessed using a pin-on-disk test under various loads, including 14, 30, 50, and 70 N, with a sliding speed of 50 mm/s over a total distance of 1 km at 37 °C. The contact parameters between the hemispherical steel pin and 3D-printed PEEK disks, involving contact pressures over the circle of contact, were observed to increase as the load increased. The results indicated that the wear coefficient exhibited a rise from 1.418   ×   10 − 5 to 2.089   ×   10 − 1   as the applied loads increased, signaling a shift from mild to severe wear regimes. Fetal Bovine Serum (FBS) as a lubricant exhibited a mixed mechanism, ascertained through the Stribeck curve, as well as a minimum fluid film thickness of 1.346 nm under an isoviscous–elastic regime, as calculated by the maximum load. Moreover, the mechanism governing wear during sliding, influenced by both normal axial and shear loads, primarily involved adhesion. [ABSTRACT FROM AUTHOR]

This paper deals with the experimental procedures of lock-in thermography (LIT) for polyetheretherketone (PEEK), which is used as a lightweight material in various industrial fields. The LIT has limitations due to non-uniform heating by external optic sources and the non-uniformity correction (NUC) of the infrared (IR) camera. It is generating unintended contrast in the IR image in thermal imaging inspection, reducing detection performance. In this study, the non-uniformity effect was primarily improved by producing an equivalent array halogen lamp. Then, we presented absolute temperature compensation (ATC) and temperature ratio compensation (TRC) techniques, which can equalize the thermal contrast of the test samples by compensating for them using reference samples. By applying compensation techniques to data acquired from the test samples, defect detectability improvement was quantitatively presented. In addition, binarization was performed and detection performance was verified by evaluating the roundness of the detected defects. As a result, the contrast of the IR image was greatly improved by applying the compensation technique. In particular, raw data were enhanced by up to 54% using the ATC compensation technique. Additionally, due to improved contrast, the signal-to-noise ratio (SNR) was improved by 7.93%, and the R2 value of the linear trend equation exceeded 0.99, demonstrating improved proportionality between the defect condition and SNR. [ABSTRACT FROM AUTHOR]

During implant maintenance, preserving a smooth surface on the machined transmucosal abutment is critical to reduce biofilm attachment and colonization. The present study compared the surface roughness and bacterial colonization of machined titanium surfaces after instrumentation with various materials. Forty-four machined grade 23 titanium discs were instrumented with a round polyether ether ketone (PEEK) tip, a plastic curette tip, or a pure titanium curette tip with piezoelectric devices. Before and after instrumentation, the surface roughness (Ra and Rz) values were analyzed with a profilometer and scanning electron microscopy (SEM). Streptococcus sanguinis was cultured and incubated for 24 hours on the instrumented discs, and colony-forming units per milliliter were obtained for each group. Samples instrumented with the metal ultrasonic tip significantly increased surface roughness compared with the other groups. This resulted in greater colonization by S. sanguinis than surfaces instrumented with PEEK tips or the negative control. Samples instrumented with PEEK and plastic tips did not exhibit any statistically significant increase in surface roughness, and SEM analysis revealed a significantly rougher surface of discs instrumented with metal compared with discs instrumented with plastic or PEEK tips despite the possibility of debris from tip dissolution. Our results suggest that instrumentation with metal ultrasonic tips with piezoelectric devices significantly increased machined titanium's surface roughness and elicited higher biofilm formation in vitro. Meanwhile, instrumentation of machined titanium with PEEK or plastic ultrasonic tips did not affect the surface roughness or bacterial adhesion. [ABSTRACT FROM AUTHOR]

Purpose: To explore the clinical application of one‐piece polyetheretherketone (PEEK) removable partial dentures (RPDs) fabricated using a novel digital workflow and to evaluate their weights and fits in vivo and patient satisfaction. Materials and Methods: Fifteen cases with posterior partially edentulous situations were selected, and each patient received two types of RPDs, including a novel digital workflow (test group) and a conventional workflow (control group). For the test group, one‐piece RPDs were designed through three‐dimensional (3D) methods by scanning stone casts and fabricated by milling PEEK discs. Each RPD was weighed. The gaps between the oral tissue and RPDs in each group were duplicated using a polyvinylsiloxane (PVS) replica and measured by 3D analysis. A visual analog scale (VAS) was used to evaluate the patient's satisfaction. Paired t‐tests were used to compare the differences in the weight, the gaps of each RPD, and VAS values between the two groups. One‐way analysis of variance tests was used to compare the differences in the gap among different components in each group. Results: The RPD in the test group weighed less than that in the control group (p < 0.01). No statistically significant differences in the gaps of denture bases and rests (p > 0.05) were found between the two groups, but the gaps of major connectors in the test group were significantly smaller than in the control group (p < 0.05). The VAS scores for comfortableness and masticatory efficiency were not significantly different between the two groups (p > 0.05) but the scores for the aesthetic appearance of the clasps in the test group were significantly higher than that in the control group (p < 0.05). Conclusions: One‐piece PEEK RPDs manufactured using a novel digital workflow weighed less than conventional RPDs and exhibited a clinically acceptable internal fit. Although the aesthetic appearance of the PEEK clasps was superior to the control, there is still room for improvement. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) oligomers were synthesized through a solution reaction using sulfolane as a solvent, the resultant oligomers were employed to synthesize high melt viscosity PEEK through solid-state polymerization in a twin-roller mixer. The effects of polymerization time on the crystallization properties, thermal properties and flowability of PEEK were investigated. The results indicated that both the degree of crystallinity and crystallization completeness of PEEK decreased with an increase in polymerization time. The degree of crystallinity of PEEK after polymerization for 5 h decreased by about 31. 4 % as compared to that of the oligomers. All samples possessed residual weights greater than 50 % at 900 °C, indicating outstanding thermal stability. In addition, the melt viscosities of PEEKs increased significantly with an increase in the polymerization time, and it reached approximately 13-360 times as high as that of oligomers. [ABSTRACT FROM AUTHOR]

PolyEther Ether Ketone (PEEK) is a leading thermoplastic biomaterial renowned for its exceptional overall properties and suitability for processing via Fused Filament Fabrication (FFF) Additive Manufacturing (AM). Despite its widespread use in industries, its fatigue behavior remains a critically underexplored aspect. This study aims to investigate the fatigue behavior of FFF‐produced PEEK, considering variations in infill pattern (triangular or rectilinear) and layer height (0.15 mm or 0.25 mm). Fatigue tests revealed a significant influence of the infill pattern on fatigue behavior, with the rectilinear pattern outperforming the triangular one. Layer height had a negligible effect when paired with rectilinear infill. Specimens with rectilinear patterns exhibited superior fatigue performance, achieving infinite fatigue life at maximum applied stress around 70% of ultimate tensile stress. Surface roughness assessment and fracture surface analysis at scanning electron microscope enhanced the interpretation of the results. This pioneering study lays the groundwork for future research in design for AM. [ABSTRACT FROM AUTHOR]

Polymer-based self-lubricating materials are designed to improve the efficiency and reliability of mechanical systems, reducing energy consumption and material loss. Herein, inspired by the texture of the smooth leaf surface, the polyether ether ketone was first subjected to a sulfonation treatment before the plant texture was introduced to the surface of the sulfonated polyether ether ketone (SPEEK) films. The optical microscopy results indicate the successful construction of different bionic textures on SPEEK film surface. Based on the reduction in the contact area between the friction pairs, and the accommodation of abrasive debris by the uneven bionic textures, the tribological performance of SPEEK films under dry friction conditions shows unique advantages. Additionally, the wear morphology and self-lubrication mechanism of bionic textured films were investigated by 3D profilometry, SEM, and XPS. The results show that under the effect of frictional heat and frictional force, the bionic texture morphology changes to fish scale, which reduces the resistance to friction, resulting in a lower friction coefficient and wear rate. This strategy of constructing bionic textures on functional polymer surfaces using a facile process provides a reference for exploring novel self-lubricating materials. [ABSTRACT FROM AUTHOR]

In the quest for sustainable and high-performance hydrogen fuel cells, proton exchange membranes (PEMs) stand as a pivotal research focus. To overcome the significant challenge posed by the traditional trade-offs between proton conductivity and mechanical stability, this work introduces liquid-crystal-modified aramid fibers (DBAF) with highly ordered molecular arrangements and abundant sulfonic acid groups on the side chains as proton-hopping sites into a sulfonated poly (ether ether ketone) (SPEEK) matrix. The inclusion of components not only improves the proton conductivity of the membrane, but also boosts its mechanical strength. The results of our study demonstrate that the externally attached sulfonic acid groups create extra channels for the transport of protons. Additionally, the organized and consistently stable hydrogen-bond network enables the Grotthuss transport mechanism within the SPEEK membrane. The 1 wt% DBAF-SPEEK composite membrane exhibits a maximum proton conductivity of 0.23 S cm−1 at 80 °C, representing a 64% increase over the baseline SPEEK membrane's 0.14 S cm−1. Simultaneously, the tensile strength at normal room temperature is 39.7 MPa, exhibiting an improvement of 86% compared to the initial value of 21.3 MPa. Additionally, the swelling ratio is lowered by 18.69%. Compared with the baseline membrane, the DBAF-enhanced SPEEK composite membrane exhibits superior mechanical stability and proton conductivity within a moderate temperature range (30–80 °C). Consequently, this work offers valuable insights for the development of novel proton-conductive materials. [Display omitted] • A Novel PEM developed using SPEEK and liquid-crystal-modified aramid fibers. • DBAF resolves trade-off between proton conductivity and mechanical stability. • Grafted sulfonic acid groups add new proton transport pathways. • Grotthuss mechanism dominates proton transport in the composite membrane. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulations were first employed to achieve the optimal sintering temperature of carboxyl-functionalized graphene (GNS-COOH)-modified polyether ether ketone (PEEK)/polytetrafluoroethylene (PTFE) composites. A model of GNS-COOH/PEEK/PTFE composites was constructed to simulate the effects of different sintering temperatures on the mechanical and tribological properties, as well as their underlying atomic mechanisms. Samples of PTFE composites were prepared and characterized through experimental methods. Results revealed that the sintering temperature significantly affects the intermolecular forces, mechanical properties, and tribological characteristics of the composites. The agglomeration of the PEEK/PTFE composite matrix was effectively mitigated by introducing GNS-COOH. When the sintering temperature was controlled at 360 °C, the compressive strength of GNS-COOH/PEEK/PTFE composites was improved compared to GNS/PEEK/PTFE composites, albeit with a slight reduction in wear resistance. This study provides a theoretical reference for the preparation process and performance evaluation of new materials. [ABSTRACT FROM AUTHOR]

Highlights Carbon fibers woven‐ply reinforced polyether ether ketone (C/PEEK) thermoplastic composites are widely used in aerospace and high‐tech industries because of their exceptional resistance to low‐velocity impact. In this paper, experimental investigation is carried out to determine the low‐velocity impact performance of C/PEEK laminates at room temperature (RT) and high temperature (90°C and 150°C) environments. Both macroscopic and microscopic analyses are applied to examine the influence of temperature on the mechanical response and damage mode of the material. The attention of this investigation is on impact parameters such as maximum contact force, energy absorption rate, indentation depth, and damage mode. The findings show significant changes in material stiffness, rate of energy absorption, and indentation depth with rising temperature. Temperature variations have a notable effect on the PEEK matrix plasticity, C/PEEK composite interlaminar properties, crack initiation and propagation, and damage mode at the overlaps of warp and weft fibers, resulting in a transition from brittle to ductile failure. Experimental investigation is carried out to study the low‐velocity impact performance of C/PEEK. The effects of impact energy and environmental temperature on the low‐velocity impact performance of C/PEEK are investigated. The mechanism of how environmental temperature affects the damage mode of C/PEEK is investigated. [ABSTRACT FROM AUTHOR]

Short fiber reinforced thermoplastic composites (SFRTC) have gained popularity in the material extrusion (MEX) method, which is an additive manufacturing (AM) technology, allowing for the simpler and more cost-effective production of polymer composites. However, parts produced using MEX 3D printing technology often exhibit poor mechanical properties and surface quality compared to products manufactured using injection molding, which is one of the main disadvantages of this method. Various methods are used to overcome these challenges, such as production in a vacuum environment, heat-based processes, ultrasonic vibrations, and others. The objective of this study was to achieve parts with lower porosity and improved mechanical properties when printed in a vacuum environment compared to an atmospheric environment. Additionally, an investigation into the optimization of printing parameters was conducted to determine the parameters that yield the highest mechanical properties. For this purpose, SFRTC parts were printed at different vacuum levels (0.5, 10, 100 mbar), and they were subjected to flexural tests to determine their mechanical properties. The results showed that the flexural stress and elastic modulus of the samples produced in a 0.5 mbar vacuum environment increased by 79.75% and 39.41%, respectively, compared to samples produced in an atmospheric environment. Furthermore, the cross-sectional images of the samples were examined using an optical microscope, revealing the lowest porosity in the samples printed in 0.5 mbar vacuum environment. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) sulfonation process is a reasonably easy but time‐consuming to manufacture composites. This study focuses on altering PEEK powder in a sulfuric acid solution via a sulfonation process to develop sulfonated PEEK (SPEEK) resin for the fiber‐reinforced thermoplastic composite manufacturing and characterization steps. In this study, about 5 wt% PEEK powder was sulfonated in 98% sulfuric acid solution for 12 h at 65°C. The water bath technique was used for the precipitation process to obtain the SPEEK polymer. After proper washing and drying, the SPEEK matrix (resin) was obtained by dissolving it in dimethylformamide in a ratio of 1:2. This resin solution was then used to manufacture thermoplastic Kevlar and glass fiber‐reinforced composites employing wet layup process and cured at an elevated temperature under pressure. These SPEEK composites passed the flame retardancy UL94 test with a V0 rating. The average water contact angle of the glass fiber‐ and Kevlar‐SPEEK composites is 93.67° and 102.24°, respectively. The average tensile strength values of these composites were found 222.22 and 284.35 MPa, correspondingly. The smoke density and toxicity tests of the glass fiber‐SPEEK composite confirmed lower smoke generation with the modifications. These SPEEK‐fiber composites can be considered for various industrial applications, including aviation, energy, drone, defense, and automotive. [ABSTRACT FROM AUTHOR]

Highlights This study delved into the Mode I fracture behavior of laser‐assisted automated fiber placement (AFP) in situ consolidated thermoplastic composite laminates under different curing pressures. In compliance with ASTM D5528 standards, T700 carbon fiber reinforced polyether ether ketone (T700‐CF/PEEK) double cantilever beam (DCB) specimens were fabricated and segregated into three test groups subjected to distinct roller pressures: DCB‐100N, DCB‐500N, and DCB‐1500N. The fracture toughness of these specimens was then inversely characterized by employing an optimized ASTM‐based data reduction methodology. A kind of tri‐linear cohesive zone model (CZM) incorporating the fracture process zone (FPZ) length was developed to simulate delamination behavior, showing good agreement between experimental results and simulation predictions. Compared with the other two test groups, DCB‐1500N specimens have more inter‐laminar bridging fibers and higher propagated toughness. Although the length of fiber bridging area is shorter, the fiber bridging density is higher, so the influence of fiber bridging on toughness is more pronounced in the DCB‐1500N specimens. This study provides theoretical guidance for the impact resistance design of thermoplastic composites (TPCs), offering valuable insights into the intrinsic relationship between material processing and fracture damage mechanisms. Explore the characteristic interlaminar fracture behavior of thermoplastic laminates made by AFP under different curing pressures. Develop a more accurate tri‐linear CZM model to describe the plastic deformation at crack tips and fiber bridging during the delamination process. Unveil the intrinsic relationship between AFP curing pressure and ductile fracture mechanism of thermoplastic composites. [ABSTRACT FROM AUTHOR]

Maxillofacial bone defects can severely impact quality of life by impairing physiological functions such as chewing, breathing, swallowing, and pronunciation. Polyether ether ketone (PEEK) is commonly used for the repair of maxillofacial defects due to its mechanical adaptability, while its osteogenic properties still need refinement. Herein, we have utilized the piezoelectric effect exhibited by barium titanate (BTO) under low-intensity pulsed ultrasound (LIPUS) to develop an ultrasound responsive PEEK (PDA@BTO-SPEEK, PBSP) through the mediating effect of polydopamine (PDA), for repairing maxillofacial bone defects. After modification by PDA@BTO, PBSP possesses better hydrophilicity, which is conducive to cell growth and adhesion. Simultaneously, by virtue of the piezoelectric characteristics of BTO, PBSP obtains a piezoelectric coefficient that matches the bone cortex. Notably, when PBSP is stimulated by LIPUS, it can generate stable electricity and effectively accelerate the osteogenic differentiation of osteoblasts through the regulation of the Piezo1-induced calcium (Ca2+) influx and Akt/GSK3β/β-catenin pathway. In addition, PBSP presents satisfactory therapeutic effects in rat skull defect models, and its osteogenic efficiency can be further improved under LIPUS stimulation with high tissue penetration. Collectively, PBSP + LIPUS exhibits great potential as a promising alternative strategy for the repair of maxillofacial bone defects. [ABSTRACT FROM AUTHOR]

Chemical recycling and upcycling offer promising approaches for the management of plastic wastes. Hydrodeoxygenation (HDO) is one of the appealing ways for conversion of oxygen‐containing plastic wastes, including polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycarbonate (PC), polyphenyl ether (PPO), and polyether ether ketone (PEEK), into cyclic alkanes and aromatics in high yields under mild reaction conditions. The challenge lies in achieving C−O activation while preserving C−C bonds. In this review, we highlight the recent advancements in catalytic strategies and catalysts for the conversion of these oxygen‐containing plastic wastes into cycloalkanes and aromatics. The reaction systems, including multi‐step routes, direct HDO and transfer HDO methods, are exemplified. The design and performance of HDO catalysts are systematically summarized and compared. We comprehensively discuss the functions of the catalysts' components, reaction pathway and mechanism to gain insights into the HDO process for efficient valorization of oxygen‐containing plastic wastes. Finally, we provide perspectives for this field, with specific emphasis on the non‐noble metal catalyst design, selectivity control, reaction network and mechanism studies, mixed plastic wastes management and product functionalization. We anticipate that this review will inspire innovations on the catalytic process development and rational catalyst design for the HDO of oxygen‐containing aromatic plastics to establish a low‐emission circular economy. [ABSTRACT FROM AUTHOR]

Objective: Biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) is an emerging, minimally invasive technique performed under biportal endoscopic guidance. However, concerns regarding cage subsidence and sufficient fusion during BE-TLIF necessitate careful selection of an appropriate interbody cage to improve surgical outcomes. This study compared the fusion rate, subsidence, and other radiographic parameters according to the material and size of the cages used in BE-TLIF. Methods: In this retrospective cohort study, patients who underwent single-segment BE-TLIF between April 2019 and February 2023 were divided into 3 groups: group A, regular-sized three-dimensionally (3D)-printed titanium cages; group B, regular-sized polyetheretherketone cages; and group C, large-sized 3D-printed titanium cages. Radiographic parameters, including lumbar lordosis, segmental lordosis, anterior and posterior disc heights, disc angle, and foraminal height, were measured before and after surgery. The fusion rate and severity of cage subsidence were compared between the groups. Results: No significant differences were noted in the demographic data or radiographic parameters between the groups. The fusion rate on 1-year postoperative computed tomography was comparable between the groups. The cage subsidence rate was significantly lower in group C than in group A (41.9% vs. 16.7%, p=0.044). The severity of cage subsidence was significantly lower in group C (0.93±0.83) than in groups A (2.20±1.84, p=0.004) and B (1.79±1.47, p=0.048). Conclusion: Cage materials did not affect the 1-year postoperative outcomes of BE-TLIF; however, subsidence was markedly reduced in large cages. Larger cages may provide more stable postoperative segments. [ABSTRACT FROM AUTHOR]

This research investigates using Polyether ether ketone (PEEK) in dental prosthetics, focusing on enhancing the mechanical properties, adhesion capabilities, and environmental sustainability through AI-driven data analysis and advanced surface treatments. The objectives include improving PEEK's adhesion to dental types of cement, assessing its biocompatibility, and evaluating its environmental impact compared to traditional materials. The methodologies employed involve surface treatments such as plasma treatment and chemical etching, mechanical testing under ASTM standards, biocompatibility assessments, and lifecycle analysis. AI models predict and optimize mechanical properties based on extensive data. Significant findings indicate that surface-treated PEEK exhibits superior adhesion properties, maintaining robust mechanical integrity with no cytotoxic effects and supporting its use in direct contact with human tissues. Lifecycle analysis suggests PEEK offers a reduced environmental footprint due to lower energy-intensive production processes and recyclability. AI-driven analysis further enhances the material's performance prediction and optimization, ensuring better clinical outcomes. The study concludes that with improved surface treatments and AI optimization, PEEK is a promising alternative to conventional dental materials, combining enhanced performance with environmental sustainability, paving the way for broader acceptance in dental applications. [ABSTRACT FROM AUTHOR]

Biomaterials consist of both natural and synthetic components, such as polymers, tissues, living cells, metals, and ceramics. Their purpose is focused on repairing or replacing malfunctioning living tissues and organs. Therefore, it is imperative to ensure the safety and sterility of biomaterials before any contact with living tissue. Ultraviolet (UV)-C irradiation for biomaterial disinfection has been considered due to the high recurrence rate of bacterial infections and to prevent resistance. Physical composition and surface properties and UV-C sensitivity of microorganisms can alter its efficacy. The main objective of this study was to evaluate the efficacy of UV-C in terms of microbial lethality and additional underlying factors contributing to its performance, namely the surface properties. For this purpose, twelve different strains were first screened, from which four microorganism species known to have the ability to cause nosocomial infections were further tested, namely Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Candida glabrata. These microorganisms were inoculated onto slides and disks of various bio contact surfaces, including glass (GLS), titanium (Ti), and poly ether etherketone (PEEK), and exposed to UV-C. The results demonstrate that bacterial pathogens on biomaterial surfaces respond differently to UV-C light exposure, and the bactericidal effect decreased in this order: glass, PEEK, and Ti (0.5 to 2.0 log reduction differences). P. aeruginosa ATCC 27853 on glass surfaces was reduced to an undetectable level after being exposed to 6.31 J.cm−2 of UV-C, displaying the highest reduction rate observed among all the tested microorganisms, 2.90 J−1.cm−3, compared to Ti and PEEK. Similarly, a higher reduction in C. glabrata ATCC 2001 was observed on glass; the modeled inhibition displayed a rate of 1.30 J−1.cm−3, the highest observed rate among yeast, compared to Ti and PEEK, displaying rates of 0.10 J−1.cm−3 and 0.04 J−1.cm−3, respectively. The inactivation rates were higher for less hydrophobic materials with smoother surfaces as compared to biomaterials with rougher surfaces. [ABSTRACT FROM AUTHOR]

The rapid technological progress of large-scale CNC (computer numerical control) systems for Screw Extrusion Additive Manufacturing (SEAM) has made the overprinting of composite laminates a much-discussed topic. It offers the potential to efficiently produce functionalised high-performance structures. However, bonding the 3D-printed structure to the laminate has proven to be a critical point. In particular, the bonding mechanisms must be precisely understood and controlled to ensure in situ bonding. This work investigates the applicability of healing models from 3D printing to the overprinting of thermoplastic laminates using semi-crystalline, high-performance material like PEEK (polyether ether ketone). For this purpose, a simulation methodology for predicting the bonding behaviour is developed and tested using experimental data from a previous study. The simulation consists of a transient heat analysis and a diffusion healing model. Using this model, a qualitative prediction of the bond strength could be made by considering the influence of wetting. It was shown that the thermal history of the interface and, in particular, the tolerance of the deposition of the first layer are decisive for in situ bonding. The results show basic requirements for future process and component developments and should further advance the maturation of overprinting. [ABSTRACT FROM AUTHOR]

The development of hydroxyapatite (HAp) and polyether ether ketone (PEEK) biocomposites has been extensively studied for bone repair applications due to the synergistic properties of the involved materials. In this study, we aimed to develop HAp/PEEK biocomposites using high-energy ball milling, with HAp concentrations (20%, 40%, and 60% w/v) in PEEK, to evaluate their physicochemical, mechanical, cytotoxicity, and antimicrobial properties for potential applications in Tissue Engineering (TE). The biocomposites were characterized by structure, morphology, apparent porosity, diametral compression strength, cytotoxicity, and antimicrobial activity. The study results demonstrated that the HAp/PEEK biocomposites were successfully synthesized. The C2 biocomposite, containing 40% HAp, stood out due to the optimal distribution of HAp particles in the PEEK matrix, resulting in higher compression strength (246 MPa) and a homogeneous microstructure. It exhibited antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, with no cytotoxicity observed. These properties make the C2 biocomposite promising for regenerative medicine applications, combining mechanical strength, bioactivity, and biocompatibility. [ABSTRACT FROM AUTHOR]

The fouling behavior of whey protein concentrate (WPC) in food‐grade polyether ether ketone (PEEK) heat exchangers was compared to benchmark stainless steel (SS) to evaluate if fouling can be better mitigated by using PEEK. No research has been conducted on WPC fouling behavior of PEEK at WPC concentrations of 2–6 g/L and heat flux densities of 45–55 kW/m2. It was found that PEEK materials led to a reduction in heat resistance of up to 40%. At WPC concentrations of 6 g/L, a fouling factor of 0.9 m2 K/kW was measured for PEEK compared to 1.6 m2 K/kW for SS. Despite a constant heat flux, fouling curves for PEEK showed an asymptotic behavior, whereas linear fouling was observed for SS. To achieve a comparable heat resistance between PEEK and SS heat exchangers, the operating time could be extended by 9 h when using PEEK materials. Investigations of the deposit mass showed that even though the heat transfer resistance is limited on PEEK, fouling continued to grow at a decreased rate. It was found that the fluid started to evaporate underneath the fouling layer, which led to a partial detachment of the fouling layer and therefore mitigated the heat resistance effects of fouling. To test whether these results are transferable to larger setups, experiments on a scale‐up apparatus were conducted. A very similar behavior was qualitatively observed; however, measured deposition deviated on average by 18%. PEEK surfaces also showed great promise regarding cleanability, with fouling layers detaching completely after drying for 10 min and restarting the process. This restored the heat transfer coefficient to its clean state. A cleaning in place therefore seems feasible. In contrast, fouling layers on SS did not detach through drying and had to be chemically cleaned to restore its heat transfer capacity. [ABSTRACT FROM AUTHOR]

The editorial discusses the increasing attention and importance of additive manufacturing (AM) techniques in the fabrication of advanced composites. It highlights various studies that have explored different AM processes, such as extrusion-based methods, fused filament fabrication, and electron-beam AM, to produce composites with improved mechanical properties. The editorial also mentions research on modeling and characterization of structure-property performance, as well as efforts to enhance the mechanical performance of AM-fabricated composites through hybrid approaches and continuous fiber integration. However, it acknowledges that there is still room for improvement in the mechanical properties of AM-fabricated composites compared to those created with conventional fabrication methods. The collection of studies presented in the editorial aims to contribute to the advancement of AM technology for advanced composites. [Extracted from the article]

This study reports on the tribological performance of aromatic thermosetting co-polyester (ATSP) and polyether ether ketone (PEEK)-based polymer composite coatings mixed with PTFE filler. The coatings were tested across a wide temperature range from −180 to 110 °C to simulate the environmental temperatures on Titan, Moon, and Mars, which are of particular interest for NASA's future exploratory missions. An experimental setup was developed to conduct the pin-on-disk experiments under dry sliding conditions and extreme temperature and contact pressure. Transfer film formation and its characteristics were found to play significant roles in the tribological performance, and the characteristics of the film were temperature-dependent. The XPS and SEM analysis indicated the increase of the PTFE content in the transfer film as the temperature decreased to cryogenic conditions. The coefficient of friction did not follow a linear trend with temperature and was minimum at 110 °C and maximum at −180 °C. ATSP coating showed superior performance with lower friction and unmeasurable wear at all temperatures, whereas PEEK coating exhibited maximum wear at 25 °C followed by −180, and 110 °C. [ABSTRACT FROM AUTHOR]

Our previous study (Polymer Composites 2023, 44: 1252–1263) revealed the positive role of rubber in modifying the tribological properties of polymer composites. This concept was applied here by incorporating synthetic Eucommia rubber (TPI) to 3D printed polyether ether ketone (PEEK) skeletons with different infill densities. The formation of TPI/PEEK composite improved the friction and wear of PEEK matrix with some reduction in mechanical performance. The composite with 70% infill density is recommended in terms of its overall performance. Based on the morphological and chemical analysis, the composite's wear mechanism was discussed. The findings of this present study could pave a new route to modify friction‐reduction and anti‐wear performance of PEEK. Highlights: Novel composites were successfully prepared from thermodynamically incompatible synthetic Eucommia rubber (TPI) and polyether ether ketone (PEEK).The tribological properties of TPI/PEEK composites were studied in association with the infill density of PEEK.The TPI rubber helped improve the friction and wear properties of PEEK thanks to its role in enhancing the formation of transfer films on the counter steel surface. [ABSTRACT FROM AUTHOR]

Biomimetic hydrogel lubrication coatings with high wettability and low friction show great promise in tissue engineering, wound dressing, drug delivery, and intelligent sensing. Inspired by the hierarchical structure of natural cartilage, a layered hydrogel coating was constructed to functionalize rigid polyetheretherketone (PEEK). The layered hydrogel coating features a structural design comprising a top soft layer and a middle robust layer. The porous structure of the top soft hydrogel layer stores water molecules, providing surface lubrication, while the dense structure of the middle robust hydrogel layer offers load-bearing capacity. These synergistic effects of the gradient hydrogel layer endow the PEEK substrate with an ultra-low coefficient of friction (COF~0.010 at 5 N load), good load-bearing capacity (COF~0.031 at 10 N load), and excellent wear resistance (COF < 0.05 at 5 N load after 20,000 sliding cycles). This study introduces a novel design paradigm for robust hydrogel coatings with exceptional lubricity, displaying the potential application in cartilage replacement materials. [ABSTRACT FROM AUTHOR]

An inexpensive membrane with high proton conductivity and high fuel cell performance, which can be an alternative to Nafion for PEMFC (Proton exchange membrane fuel cell), will overcome the obstacle to widespread commercialization of fuel cells due to high cost. For this purpose, SPEEK (sulfonated polyether ether ketone)-PVA (polyvinyl alcohol) blend membranes with colloidal silica additives were synthesized in this study. Ludox AS-40 was used as the colloidal silica source and the blend membrane was prepared by solution casting method. Water uptake capacity, swelling property, size change, dynamic mechanical analysis, ion exchange capacity, AC impedance analysis, hydrolytic and oxidative stability experiments of the synthesized Ludox additives blend membranes for fuel cell application were carried out, and the membranes were also characterized by FTIR (Fourier transform infrared) analysis. While the water uptake capacities of SPEEK/PVA membranes containing 1% Ludox, 5% Ludox, and 10% Ludox at room temperature were found to be 14.08%, 14.84%, and 16.6%, respectively, the water uptake capacities at 80oC increased to 14.73%, 15.17%, and 17.11%. The proton conductivities of 1% Ludox, 5% Ludox and 10% Ludox doped SPEEK/PVA membranes at 80oC were 0.25 S/cm, 0.56 S/cm, and 0.65 S/cm, respectively. Similarly, ion exchange capacities were determined to be 1.41 meq/g, 1.63 meq/g, and 1.71 meq/g, respectively. All Ludox-added membranes exhibited excellent hydrolytic stability, retaining approximately 88% of their mass after 650 h. In addition, in oxidative stability experiments carried out in 4 ppm Fe+ 2 at 80oC, the 10% Ludox-added membrane exhibited the highest weight loss of 88.8% at the end of 24 h, while the 5% Ludox-additive membrane retained 91.6% of its total weight. Considering the proton conductivity and longevity tests of the synthesized membranes, they are thought to be promising structures. [ABSTRACT FROM AUTHOR]

Recently, thermoplastic resins were used as matrix to synthesize carbon fiber‐reinforced thermoplastic (CFRTP) for recycling it easily. In this study, a CFRTP with excellent mechanical properties and heat resistance was synthesized using a polyether ether ketone (PEEK) as a matrix resin. The PEEK resin was modified to form cross‐linked structures through Friedel–Crafts reaction alkylation. The synthesis temperature of CFRTP was optimized considering the mechanical properties of PEEK, and its heat resistance was enhanced because of the cross‐linked structures. Further, the cross‐linked PEEK resin was partially used as a matrix resin, and the mechanical properties of the CFRTP were enhanced. We plan to develop a method for recycling CFRTP using PEEK and crosslinked PEEK for synthesizing C/C composites by focusing on the high heat resistance of the crosslinked PEEK containing a large amount of carbon and reducing mass loss after heat treatment. Highlights: CC bonds were introduced into the polyether ether ketone (PEEK) resin by Friedel–Crafts reaction alkylation.Thermal properties of PEEK were enhanced by hypercrosslinking reaction.Optimization of synthesized temperature was investigated to fabricate carbon fiber‐reinforced thermoplastic (CFRTP).Mechanical properties were enhanced CFRTP modified with hypercrosslinking reaction. [ABSTRACT FROM AUTHOR]

To explore the morphology of polyetheretherketone (PEEK), this study employed fast scanning calorimetry (FSC) and scanning electron microscopy (SEM). The objective was to observe the PEEK microstructure under various thermal profiles replicating the additive manufacturing material extrusion process. Samples were observed using SEM directly from the FSC chips, allowing high-accuracy evaluation of the microstructure relative to the thermal profiles. This approach allowed for the evaluation of the microstructure with high accuracy concerning the thermal profiles to which the samples were previously exposed. Each sample was coated with a 10 nm layer of gold–palladium (20–80% ratio), and no etching was necessary to observe the micro features of the microstructure. The approach enabled successful observation and quantification of PEEK microstructure, linking substrate temperature and temperature peaks to microstructural outcomes. Notably, temperature peaks during the process enhanced the formation of well-developed, thick lamellae due to increased chain mobility. Additionally, embryos formed post-remelting of the substrate structure were observed. [ABSTRACT FROM AUTHOR]

Film heterostructures of compositions Ag/Au/Ti and Ag/Au/CFR-PEEK are obtained by thermal evaporation with subsequent deposition of metallic gold sublayers and silver nanostructures on modern biomaterials (Ti-6Al-4V alloy, polyether ether ketone CFR-PEEK). Silver concentration is varied within 2.1-20.8 µg/cm2 by changing the initial metal portion (1.2-5 mg) and the number of successive depositions (1–3). According to SEM data, Ag nanofilms with a thickness up to 10-15 nm are formed on the surface of gold sublayers. According to XPS results, gold is present in the metallic state on the surface of biomaterials whereas along with metal, the Ag2O oxide phase is detected for silver. The dynamics of silver dissolution from the Ag/Au surface is analyzed by ICP-AES (2-48 h). It is found that regardless of the silver concentration, the samples demonstrate moderate dynamics of releasing metal ions; some amount of gold is detected together with silver in the solution. The absence of cytotoxicity of the synthesized film heterostructures in vitro (L-929 cells, viability >95-98%) is shown. Heterostructures completely suppress the growth of colonies of Gram-negative (P. aeruginosa) and Gram-positive (S. aureus) bacteria after 6 h and 24 h action respectively. [ABSTRACT FROM AUTHOR]

Studies on dental implant abutments' geometric design and material selection offer significant innovations and results. These studies aim to improve the abutments' functionality and aesthetic performance, minimize microcavities' formation, and ensure implant-supported prostheses' longevity. For example, CAD-CAM fabricated custom abutments have been found to produce a better marginal fit and fewer microgaps than standard abutments. In an in vitro study, transepithelial abutments offered lower microgap values than titanium-based abutments and provided a better fit at the implant–abutment interface. It is known that studies to improve mechanical and biological performance with Polyether Ether Ketone (PEEK) material have been addressed. New materials such as PEEK and zirconia have offered significant advantages in biocompatibility and aesthetics. Along with those studies, different abutment designs are also important. Abutment geometry is optimized to improve stress distribution and minimize peri-implant bone loss. In implant and abutment connections with different angles, mechanical life performances may vary depending on static and dynamic load. These studies emphasize the importance of material research on different types of connections to improve dental implants' durability, homogeneous load distribution, and reliability. The abutment parts used in implant treatment are insufficient to distribute the load homogeneously against chewing pressure due to their materials and geometry. Non-uniform load distribution damages the abutment and the prosthetic crown, accelerating the wear process. This study aimed to create different abutment designs to improve dental implants' biomechanical performance and longevity. This study aimed to increase the mechanical durability of the implant–abutment connection by reducing stress concentrations in response to masticatory compression on the abutment in different directions and forces and to guarantee the long-term success of the implant system by providing a more homogeneous stress distribution. It aimed to apply different forces in the axial direction to these models in a simulation environment and to calculate and compare the deformation and stress load distribution. As a method, three-dimensional models of the parts used in implant treatments and forming the implant system were designed. Different abutment designs were created with these models. Taking the current material values used in implant treatments as a reference, finite element analysis (FEA) was performed by applying different axial loads to each implant system model in the ANSYS software (version 24.1). Comparative analysis graphs were prepared and interpreted for the stress values obtained after the applied load. This study evaluated the mechanical performance of different abutment models (A, B, C, D, and E) under a 100 N load using the Kruskal–Wallis test. The Kruskal–Wallis test showed significant differences between the groups (p < 0.001). The greatest difference was observed between models E and A (q′ = 6.215), with a significant difference also found between models C and A (q′ = 3.219, p < 0.005). Regarding stress values, the highest stress on the abutment was observed in Model B (97.4 MPa), while the lowest stress was observed in Model E (9.6 MPa). The crown exhibited the highest stress in Model B (22.7 MPa) and the lowest in Model E (17.3 MPa). The implant stress was highest in Model C (14.8 MPa) and lowest in Model B (11.3 MPa). The stress values for the cortical bone and cancellous bone were quite similar across the models, showing no significant differences. These findings indicate that the abutment design and material selection significantly impact mechanical performance. Among the implant systems created with five different abutment models, in which the existing abutment geometry was also compared, homogeneous and axial distribution of the load on the abutment was achieved, especially with viscoelastic and surface area increased abutment designs. Clinically, the inadequacy and limited mounting surface or geometry of the abutments used in today's implant treatment applications have led to different design searches. It was concluded that the designs in this study, which are considered alternatives to existing abutment models, contribute positively to the mechanical life of the abutment material, considering the von Mises stresses and directions. This study brings a new perspective to today's practices and offers an alternative to treatment practices. [ABSTRACT FROM AUTHOR]

Background: Reconstructing cranio-maxillo-facial defects presents significant challenges. This study evaluates the results of polyetheretherketone patient-specific implants (PEEK PSIs) in primary and secondary cranio-maxillo-facial reconstructions, with a focus on aesthetic and functional outcomes and long-term complications. Methods: From October 2009 to February 2023, 45 patients underwent cranio-maxillo-facial reconstructions with PSIs. Patients aged 18 years or older, with a minimum follow-up period of 12 months, were included. The morpho-functional outcome was evaluated through a modified Katsuragy Scale, the Visual Analogue Scale (VAS) for pain, and four FACE-Q|Aesthetics© scales. Results: In total, 44 PSIs were placed in 37 patients (51.3% males; mean age 45.1 years). The main cause of the defect was the resection of a tumor (55.4%). Mean follow-up was 78.6 months. Clinical evaluations showed an improvement in the postoperative period both in patient's and surgeon's scores (p: 0.01 and p: 0.002, respectively). Subgroup analysis confirmed a significant improvement in patients undergoing cranioplasty (p = 0.02) and mandible reconstruction (p = 0.03). No cases of prosthesis dislocation, rupture, or long-term infection were recorded. Conclusions: PEEK PSIs offer significant advantages in craniofacial reconstructions. Despite challenges in predicting soft tissue adaptation, overall patient satisfaction was high with no long-term complications. Future improvements should focus on predicting and enhancing soft tissue adaptations. [ABSTRACT FROM AUTHOR]

Achieving a strong bond between Polyetheretherketone (PEEK) and veneering composites is challenging due to PEEKs low surface energy. This study examined the effects of sandblasting and bonding on the shear bond strength (SBS) between veneering composite and pigmented PEEK, considering artificial aging. Of three pigmented PEEK compounds (DC4420R, DC4450R, DC4470R; Evonic Operations GmbH, Marl, Germany), 40 specimens each were milled and polished up to 2500 grit. Prior to veneering, specimens were divided into 4 subgroups: Subgroup 1: Polishing; 2: Polishing + bonding; 3: Sandblasting; 4: Sandblasting + bonding. Sandblasting was performed using Al 2 O 3. Adhesive was an agent containing MMA (Signum Universal Bond, Kulzer GmbH, Hanau, Germany). After veneering (Composite, Kulzer GmbH) the subgroups were divided into 2 subgroups. One subgroup was immersed in 37 °C warm distilled water for 24 h. The second subgroup was artificially aged by thermocycling (TCL) with 5000 cycles in distilled water (5 °C / 55 °C; 30 s). Surface roughness, water contact angles and failure modes were recorded. SBS was measured using a universal testing machine. Results demonstrated that the combination of sandblasting and bonding significantly improved the SBS compared to polishing alone. PEEK color did not significantly influence the SBS. Aging by TCL had a negative effect on the SBS. Sandblasting and the use of an adhesive containing MMA were found to be effective in achieving satisfactory SBS between veneering composite and pigmented PEEK surfaces. These pretreatment methods demonstrate their potential for establishing durable and reliable bonding in clinical applications. [ABSTRACT FROM AUTHOR]

The coupling of magnetic, thermal and structural force fields exists in the design, manufacture and operation of the magnetic core of transformer and motor, which makes the experimental data obtained from the standard magnetic properties measurement inconsistent with the actual problem. In order to obtain the magnetic properties measurement data of soft magnetic materials such as electrical steel sheet under multiple physical factors, the magnetic circuit structure was improved on the basis of the standard single sheet tester. At the same time, anti-bending clips made of polyether ether ketone were installed in order to prevent the bending deformation of the sample sheet during the application of tensile stress which would lead to uneven force. Then0 this basic structure of the tester under the coupling of temperature and stress is designed. In order to further improve the excitation performance of the tester and the magnetization uniformity of the sample, combined with COMSOL and MATLAB co-simulation, adaptive genetic algorithm was used to optimize the size of the yoke and excitation coil, thereby ensuring the uniformity of the magnetic field distribution in the measurement area of the sample. Finally, by combining simulation and specific experiments, the loss measurement results of a single sheet tester under different ambient temperatures and different stresses are studied, which proves that the tester is feasible and accurate, and the variation law of complex magnetic characteristics of electrical steel sheets under multiple physical fields is summarized. [ABSTRACT FROM AUTHOR]

This document discusses the increasing demand for biomaterials in the field of human body repair. Biomaterials are materials made of metal, polymer, bioactive glass, ceramic, or a combination of these materials that are biocompatible and can be used to repair or replace tissue functions in the body. The document highlights various articles that explore the design and applications of biomaterials, including non-invasive blood glucose monitoring, 3D printing for maxillofacial surgery and artificial livers, reverse engineering for accurate bone models, and the mechanical behavior of different biomaterials used in medical procedures. The articles cover a range of topics related to biomaterials and their potential applications in healthcare. [Extracted from the article]

Background: This study aimed to examine the effect of the force applied by rubber dam clamps made from different materials on mandibular first molar teeth with various designs of endodontic access cavities using finite element analysis. Methods: A intact tooth (IT) and seven different endodontic access cavities namely, a traditional endodontic cavity (TRADAC), a guided endodontic cavity (GEC), a conservative endodontic cavity (CAC), an ultra-conservative access cavity (UAC), a truss access endodontic cavity (TRSAC), a mesial caries access cavity (MCAC), and a distal caries access cavity (DCAC), along with two different clamp finite element models, were created. The clamp models were made of polyether ether ketone (PEEK) and stainless steel (SS). The forces applied by the clamps were calculated based on the axial section distance of the tooth, and these forces were applied to the contact areas on the tooth. Stress distribution models were calculated using maximum von Mises (vM) stress. Results: The lowest vM stress under the forces applied by the SS and PEEK clamps was found in the IT model (80.914 MPa) with the PEEK clamp. The highest vM stress was found in the DCAC model (759.49 MPa) applied with the SS clamp. The forces applied by SS clamps resulted in higher vM stress values in every cavity design than those applied by PEEK clamps. Conclusion: PEEK clamps generated less force than SS clamps. However, clinicians should follow various isolation strategies (clamp made of different materials, split dam, etc.) according to different cavity types of the tooth. [ABSTRACT FROM AUTHOR]

Abstract Maxillofacial bone defects can severely impact quality of life by impairing physiological functions such as chewing, breathing, swallowing, and pronunciation. Polyether ether ketone (PEEK) is commonly used for the repair of maxillofacial defects due to its mechanical adaptability, while its osteogenic properties still need refinement. Herein, we have utilized the piezoelectric effect exhibited by barium titanate (BTO) under low-intensity pulsed ultrasound (LIPUS) to develop an ultrasound responsive PEEK (PDA@BTO-SPEEK, PBSP) through the mediating effect of polydopamine (PDA), for repairing maxillofacial bone defects. After modification by PDA@BTO, PBSP possesses better hydrophilicity, which is conducive to cell growth and adhesion. Simultaneously, by virtue of the piezoelectric characteristics of BTO, PBSP obtains a piezoelectric coefficient that matches the bone cortex. Notably, when PBSP is stimulated by LIPUS, it can generate stable electricity and effectively accelerate the osteogenic differentiation of osteoblasts through the regulation of the Piezo1-induced calcium (Ca2+) influx and Akt/GSK3β/β-catenin pathway. In addition, PBSP presents satisfactory therapeutic effects in rat skull defect models, and its osteogenic efficiency can be further improved under LIPUS stimulation with high tissue penetration. Collectively, PBSP + LIPUS exhibits great potential as a promising alternative strategy for the repair of maxillofacial bone defects.

Purpose: To evaluate the stress distribution in endocrowns and post-and-core crowns used as abutments for a Kennedy Class I removable partial denture constructed with different framework materials. Materials and Methods: 3D models of a Kennedy Class I mandible were constructed. Cobalt-chromium (Co-Cr) and polyether ether ketone (PEEK) frameworks were simulated for Models 1 and 2, respectively. An endocrown and a fiber post-and-core crown for the mandibular left and right second premolar abutments, respectively, were simulated for both models. Lithium disilicate porcelain was defined for the crowns. A 200-N occlusal force was applied in the vertical and 30-degree oblique directions. Results: The von Mises stresses were evaluated for the abutments and prostheses, and the principal stresses for the cortical bone under vertical and oblique loading. Endocrowns showed lower stress values than post-and-core crowns in both models. Post-and-core crowns generated the highest stress in Model 2 under vertical loading. The PEEK framework caused higher stress values on the abutments than Co-Cr. Compressive stresses were higher than tensile stresses in cortical bone. The highest compressive stress was observed around the left premolar cortical bone area in Model 1 under oblique loading. Oblique loading caused lower stress values than vertical loading, except for on the minor connectors and cortical bone. Conclusion: From a biomechanical perspective, endocrowns may be more advantageous than post-and-core crowns when used as abutments for a Kennedy Class I removable partial denture. In addition, Co-Cr frameworks showed more favorable stress distribution on abutments than PEEK frameworks. [ABSTRACT FROM AUTHOR]

AbstractIn the aviation industry lightweight, high-strength materials have replaced metals to lighten vehicles and reduce fuel consumption. Polymer matrix composite materials have thus been chosen because they are highly resistant to oxidation and chemicals, are lightweight compared to metals, and are simple to manufacture. The aim of this study was to increase the compatibility of carbon fiber fabric (CFF) with polyether ether ketone (PEEK) polymer. Meldrum’s acid and nitric acid modified CFFs were assessed using energy dispersive X-ray spectrometry (EDX), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The PEEK matrix composites reinforced with CFF were produced by a compression molding method. The composites were characterized by tensile strength tests, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). We concluded that the CFF modification improved the compatibility between CFF and PEEK. The enhancement of the tensile properties of the composites was another indication of this modification’s beneficial effects. [ABSTRACT FROM AUTHOR]