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Polyetheretherketone (PEEK), with good biocompatibility and similar mechanical properties to natural bone, is extensively employed in the manufacture of prostheses. However, the precision and mechanical properties of current implants are major challenges for clinical applications. In this study, the effect of pore size, raster angle and printing temperature were investigated on length, width, thickness, material consumption, compressive strength and Young's modulus. Taguchi design of experiment method was used to reduce the number of experiments and optimize the printing process parameters. Finally, predictive analysis was exploited to give the optimal set of process parameters. Experimental results indicated that the approach applied in this work provided more accurate predictions and control of the response variables. The maximum compressive strength and compressive modulus of PEEK scaffolds reached 43.4 MPa and 253.3 MPa, respectively. Therefore, the methodology of present work has the potential to meet the demand of design precision and manufacture of customized bone substitutes. [ABSTRACT FROM AUTHOR]

Proton exchange membranes (PEMs) are the core components of fuel cells, and research has long focused on how to balance their proton conductivity and durability. In this work, a series of homogeneous blend of sulfonated polyimide (SPI) and sulfonated polyether ether ketone (SPEEK) hybrid membranes with were constructed refined with sulfonated MoS 2 (H–MoS 2) and sodium lignosulfonate (SLS). The results showed that the tensile strength of the films was enhanced by 39.4% (67.84 MPa) compared to the base film. The composite films incorporating 1 wt% H-MoS 2 and 2 wt% SLS has excellent proton conductivity, which can reach 50.24 mS/cm at 80°C and 100% humidity. The embed hybrid structure constructed by H–MoS 2 and SLS, which not only effectively solves the limitations of the proton transport channel of traditional polymer materials, but also provides abundant proton transport sites, which provides a new strategy for preparing high-performance PEM. [Display omitted] • The stability of composite films was improved by organic/inorganic co-modification • H–MoS 2 and SLS together construct a continuous proton transport channel • The tensile strength of the best composite film is up to 67.84 MPa [ABSTRACT FROM AUTHOR]

Antibacterial sonothermal therapy (ASTT) is attractive for treating implant‐associated infection, which addresses the limitations of poor penetration of photothermal therapy. However, achieving implant surface‐specific ultrasound heating is incredibly challenging. Inspired by the porous acoustic metastructure in noise reduction, the acoustic metastructure would be a new strategy for attaining ASTT. Herein, an "acoustic confinement effect" is proposed to "trap" ultrasound for the metastructure TiO2 porous coating on titanium implants. The metastructure coating accomplishes specific acoustic absorption and efficient acoustic‐to‐thermal conversion, surpassing the non‐specific heating of conventional coatings. The theoretical calculation and experiment of metastructure porous coating prove the acoustic‐to‐thermal conversion mechanism, which is also validated in metastructure porous coatings on medical polyetheretherketone, indicating it is universal. Excitingly, this acoustic metastructure "trap" can capture bacteria and local sonothermal enhancement, exhibiting superior ASTT antibacterial rates (S. aureus, 99.69%; E. coil, 99.58%) at low‐power ultrasound. In addition, the metastructure TiO2 coating mimics human bone and demonstrates outstanding osseointegration. This study sheds substantial light on developing the acoustic responsive surface, broadening a new direction of acoustic metamaterials in medical applications. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc‐ion batteries are considered as promising candidates for safe and green energy storage. Yet, Zn anodes still suffer from serious challenges. Herein, an effective cation‐sieve of polyethersulfone‐modified sulfonated polyether ether ketone is developed as protective coating layer of the Zn anodes. Cation‐only transmission and dense property of the layer can protect the Zn from active water and anions, inhibiting corrosion, hydrogen evolution reaction (HER), and passivation. Zincophilic property of the layer can homogenize Zn2+ flow, and promote uniform plating of Zn. Therefore, protected symmetric Zn||Zn cell can maintain as long as 5600 h with a low polarization at 1.0 mA cm−2 and 0.5 mAh cm−2, and still long as 800 h at 5.0 mA cm−2 and 5.0 mAh cm−2. It is found that not only the dendrites but also the popular existed passivation product of Zn4SO4(OH)6·5H2O can be inhibited effectively. In asymmetric Zn||Ti cells, average Coulombic efficiency can reach 98.2%, suggesting corrosion and HER are restrained effectively. Matched with MnO2 cathode, full cells using coated Zn exhibit much better cycling performance than that using bare Zn. Moreover, Zn4O3(SO4)·7H2O (ZSH)‐assisted reversible conversion mechanism between the ZSH and ZnxHyMnO2 is revealed through operando Raman. [ABSTRACT FROM AUTHOR]

This study continues the discussion on the surface modification of polymers using an atmospheric pressure plasma (APP) reactor in air. These results complement prior research focusing on nonpolar polymers. Polymers, such as polyethylene terephthalate, polyetheretherketone, and polymethyl methacrylate, containing structurally bonded oxygen are studied, representing a range of properties such as oxygen content, crystalline/amorphous structure, polarity, functionality, and aliphatic/aromatic structure. APP induces superior wetting properties on the hydrophilic polymer surfaces with rapid and uniform modification within 0.5 s of exposure. The amorphous structures undergo additional modification for longer exposure. Moreover, the aliphatic chain structures require longer plasma exposure to reach surface modification equilibrium. The polar polymers reach a limit level of modification corresponding to a minimum water contact angle of about 50°. The surface polarity increases on average by a factor of approximately two. The equilibrium values of the adhesion work attained after post-processing recovery fall within a limited range of about 100–120 mJ/m2. The enhancement of surface functionality through the creation of oxidized groups primarily depends on the initial oxygen content and reaches a limit of about 40 at.% oxygen. The surface properties of the treated polar surfaces exhibit good stability, comparable to that of the previously tested nonpolar polymers. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) injury is one of the most prevalent factors contributing to knee instability worldwide. This study aimed to evaluate modified metal fixation techniques for ACL reconstruction compared to factory-made implants, such as polyether ether ketone (PEEK) screws, bioabsorbable screws, and modified metal implants. Methods: A retrospective cohort analysis was conducted to assess the functional outcomes of ACL using various fixation methods. Patients who underwent arthroscopic ACL reconstruction at several healthcare facilities were included in the study. The functional outcomes were evaluated using the Lysholm Knee Scoring Scale and the International Knee Documentation Committee (IKDC) score questionnaire at 6- and 12 months post-surgery. Statistical analyses, including the Shapiro–Wilk test and analysis of variance, were performed to compare outcomes among the fixation groups. Results: Thirty-three patients who underwent ACL reconstruction surgery with varying distributions across the three fixation groups (modified metal implants, PEEK screws, and bioabsorbable screws) were included in the study. As measured by the Lysholm and IKDC scores at 6- and 12 months post-surgery, the PEEK group demonstrated the highest average scores. Nevertheless, these functional outcomes were not significantly different between the groups (p = 0.140, 0.770, 0.150, and 0.200). These findings align with those of meta-analyses comparing different fixation methods for ACL reconstruction. Conclusions: While acknowledging the small sample size as a limitation, this study suggests that modified metal implants represent viable options for ACL reconstruction. The selection of fixation methods should consider patient characteristics and preferences, emphasizing biomechanical stability and long-term outcomes. Further research is needed to validate these findings and explore their biomechanical properties and cost-effectiveness. [ABSTRACT FROM AUTHOR]

The selection of process parameters is crucial in 3D printing for product manufacturing. These parameters govern the operation of production machinery and influence the mechanical properties, production time, and other aspects of the final product. The optimal process parameter settings vary depending on the product and printing application. This study identifies the most suitable cluster of process parameters for producing rotating components, specifically impellers, using carbon-reinforced Polyether Ether Ketone (CF-PEEK) thermoplastic filament. A mathematical programming technique using a rating method was employed to select the appropriate process parameters. The research concludes that an infill density of 70%, a layer height of 0.15 mm, a printing speed of 60 mm/s, a platform temperature of 195 °C, an extruder temperature of 445 °C, and an extruder travel speed of 95 mm/s are optimal process parameters for manufacturing rotating components using carbon-reinforced PEEK material. [ABSTRACT FROM AUTHOR]

Recent techniques for forming thermoplastics, such as welding, automated fibre placement or additive manufacturing, generate successive rapid heating and cooling cycles that cause the partial melting of crystals during the process. The melting of an interface is essential to guarantee a good molecular diffusion across the welded parts. Nevertheless, no model can correctly predict the melting kinetics and consequently the evolution of the crystalline degree during the layers' deposition process. The purpose of this paper was to define the melting kinetics depending on the crystallization conditions for polyetheretherketone (PEEK). Firstly, a non-isothermal crystallization model was proposed over a wide range of cooling rates from 0.1 K.s−1 to 150 K.s−1. Experimental results have highlighted a dual-mode behaviour of melting and demonstrated the dependence of melting temperatures on crystallization conditions. Based on these observations, a model was developed to predict the melting behaviour after non-isothermal crystallization. The melting model revealed that after high cooling rates, primary and secondary crystals melt separately at low temperatures, while after slow cooling rates, both structures melt simultaneously at higher temperatures. Finally, the melting model was applied to the FFF thermal cycle to illustrate the influence of process parameters on the melting kinetics during deposition. [ABSTRACT FROM AUTHOR]

The inherent structural properties and elevated processing temperatures of thermoplastic resins present new challenges in the realm of carbon fiber (CF) sizing agents. Consequently, a water‐based cross‐linkable nitro‐phthalonitrile capped polyfluorenyl ether ketone sizing agent was meticulously designed. The sizing agent exhibits superior storage stability, encapsulating particles spanning dimensions from 66.51 to 87.71 nm. The inherent mechanism during the hot‐pressing stage involves a self‐crosslinking of nitrile groups toward stable structures with unparalleled resistance to solvents. The crosslinked sizing agent boasts a remarkable glass‐transition temperature of 290°C. Noteworthy, significance is the consequential 40.1% augmentation in maximum flexural strength, along with a commendable 35% increase in interlaminar shear strength for CF‐1.5/PEEK composites in contrast to their unsized CF/PEEK counterparts. In summary, the focal aspiration of this research endeavor lies in offering a straightforward and viable methodology for the exploration of cross‐linkable sizing agents, strategically catering to both "thermoplastic processing" and "thermosetting applications." Highlights: Bulky fluorenyl unit increases the intermolecular volume of copolymer poly(fluorenyl ether ketone).The introduction of the BPF unit to the molecular elevates the thermal stability of the copolymer.Unique electron‐donating proclivity of the fluorenyl group drastically improved its reactivity.The polymerization was accomplished at a relatively low temperature of 150°C for practical applications.The ILSS, IFSS, and bending strength were noteworthy increased by 35%, 74.02%, and 40.1% [ABSTRACT FROM AUTHOR]

Polyetheretherketone (PEEK), an organic thermoplastic polymer, has gained interest in dentistry due to its excellent mechanical strength, flexibility, and biocompatibility. Furthermore, the ability to utilize CAD/CAM in the fabrication of PEEK enhances accuracy, reliability, and efficiency while also saving time. Hence, several orthodontic studies have explored the utilization of PEEK in various applications, such as archwires, brackets, fixed lingual retainers, palatal expansion devices, transpalatal arches, Tübingen palatal plates, different types of space maintainers, mini-implant insertion guides, and more. However, a complete systematic review of the available data comparing the performance of PEEK with traditional orthodontic materials has not yet been conducted. Therefore, this systematic review seeks to assess if PEEK material meets the required mechanical criteria to serve as an alternative to conventional orthodontic appliances. To ensure clarity and precision, this review will specifically concentrate on fixed appliances. This systemic review followed the PRISMA guidelines and utilized databases including PubMed/MEDLINE, Embase, Springer, Web of Science, and Wiley. Searches were restricted to English language articles from January 2013 to February 2024. Keywords such as "Polyetheretherketone" or "PEEK" and "Orthodontic" or "Orthodontic device" or "Orthodontic materials" were employed across all databases. Nine studies were incorporated, covering orthodontic archwires, brackets, and fixed lingual retainers. Based on the reviewed literature, PEEK demonstrates promising potential in orthodontic fixed appliances, offering advantages in force delivery, friction reduction, and aesthetic appeal. Further research is needed to fully explore its capabilities and optimize its application in clinical practice. [ABSTRACT FROM AUTHOR]

Background The implantation of a spacer is a common practice after anterior diskectomy in cervical spine. Polyether ether ketone (PEEK) cages have replaced titanium implants due to their better radiologic visibility and appearance in postoperative magnetic resonance imaging (MRI) scans. However, PEEK showed apparently higher nonunion rates than titanium cages. The aim of the study was to evaluate the fusion behavior of plain PEEK cages in comparison to titanium-coated PEEK (TiPEEK) cages. Method We randomized 104 patients with single-level cervical radiculopathy or mild myelopathy. They were divided into two groups of 52 patients each, receiving either a PEEK cage or the titanium-coated variant of the same cage type. The 1- and 2-year follow-ups were completed by 43 patients in the PEEK group and by 50 patients in the TiPEEK group. Fusion was determined by plain X-ray and lateral functional X-ray. Results Two years after surgery, a complete fusion was observed in 37 patients of the PEEK group (86%). Six cases were considered as nonunions. In the TiPEEK group, we found 41 fusions (82%) and 9 nonunions at this time. The difference was not considered significant (p = 0.59). The clinical evaluation of the two groups showed no difference in the neurologic examination as well in the pain scores over the time period. Conclusions Despite some assumptions about an advantage of TiPEEK over PEEK cages for fusion in cervical spine surgery, this prospective randomized controlled study did not find an accelerated or improved fusion using TiPEEK for anterior cervical diskectomy. [ABSTRACT FROM AUTHOR]

Objectives: Cranioplasty is a complex craniofacial and neurosurgical procedure that aims to reinstate the architecture of the cranial vault and elevate both its aesthetic and neurological function. Several reconstructive materials have been thoroughly explored in the search for the optimal solution for cranioplasty. This study aimed to evaluate different material used for cranial reconstruction in Oman. Methods: This retrospective study included all patients who had had cranioplasty procedures performed at Khoula Hospital, Muscat, Oman, from 2012 to 2022. Demographic information, the characteristics of the cranial defect and any complications that occurred post-operatively were analysed. Results: A total of 47 patients were included in this study. The most common cause of cranial defects was craniectomy following traumatic head injury (70.2%) along with excision of fibrous dysplasia (10.6%). The most frequently utilised material for cranial repair was autologous bone grafts (n = 28), followed by polyetheretherketone (PEEK; n = 14). Interestingly, the replacement of bone grafts from previous craniectomy showed a notably high resorption rate (71.4%), in contrast to split calvarial grafts (0%) and other types of bone grafts (14.3%). Additionally, delayed graft infection was observed in 3.6% of the bone graft group and 7.1% of the PEEK group. Conclusion: Patient-specific alloplastic implants such as PEEK have gained popularity for large and complex cranioplasty, as they provide excellent aesthetic outcomes and leave no donor site morbidity. In contrast, bone grafts remain the gold standard for small to medium-sized cranial defects. [ABSTRACT FROM AUTHOR]

Even with the best infection control protocols in place, the risk of a hospital-acquired infection of the surface of an implanted device remains significant. A bacterial biofilm can form and has the potential to escape the host immune system and develop resistance to conventional antibiotics, ultimately causing the implant to fail, seriously impacting patient well-being. Here, we demonstrate a 4 log reduction in the infection rate by the common pathogen S. aureus of 3D-printed polyaryl ether ketone (PAEK) polymeric surfaces by covalently binding the antimicrobial peptide Mel4 to the surface using plasma immersion ion implantation (PIII) treatment. The surfaces with added texture created by 3D-printed processes such as fused deposition-modelled polyether ether ketone (PEEK) and selective laser-sintered polyether ketone (PEK) can be equally well protected as conventionally manufactured materials. Unbound Mel4 in solution at relevant concentrations is non-cytotoxic to osteoblastic cell line Saos-2. Mel4 in combination with PIII aids Saos-2 cells to attach to the surface, increasing the adhesion by 88% compared to untreated materials without Mel4. A reduction in mineralisation on the Mel4-containing surfaces relative to surfaces without peptide was found, attributed to the acellular portion of mineral deposition. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) is esteemed as a high-performance engineering polymer renowned for its exceptional mechanical properties and thermal stability. Nonetheless, the majority of polymer-based lubricating materials fail to meet the contemporary industrial demands for motion components regarding high speed, heavy loading, temperature resistance, and precise control. Utilizing 3D printing technology to design and fabricate intricately structured components, developing high-performance polymer self-lubricating materials becomes imperative to fulfill the stringent operational requirements of motion mechanisms. This study introduces a novel approach employing 3D printing technology to produce PEEK with varying filling densities and conducting in situ synthesis of zeolitic imidazolate framework (ZIF-8) nanomaterials on its surface to enhance PEEK's frictional performance. The research discusses the synthetic methodology, characterization techniques, and tribological performance evaluation of in situ synthesized ZIF-8 nanomaterials on PEEK surfaces. The findings demonstrate a significant enhancement in frictional performance of the composite material under low-load conditions, achieving a minimum wear rate of 4.68 × 10−6 mm3/N·m compared to the non-grafted PEEK material's wear rate of 1.091 × 10−5 mm3/N·m, an approximately 1.3 times improvement. Detailed characterization and analysis of the worn surface of the steel ring unveil the lubrication mechanism of the ZIF-8 nanoparticles, thereby presenting new prospects for the diversified applications of PEEK. [ABSTRACT FROM AUTHOR]

The object of the study was to evaluate the suitability and trueness of the removable partial denture (RPD) framework fabricated by polyether ether ketone (PEEK) with the CAD-CAM technology in vitro. Four different types of dentition defects were selected. In each type, five PEEK RPD frameworks were fabricated by the CAD-CAM technology, while five Co-Cr RPD frameworks were made by traditional casting. The suitability of the framework was evaluated by silicone rubber film slice measurement and the three-dimensional image overlay method. The trueness of the PEEK framework was detected by the three-dimensional image overlay method. Data were statistically analyzed with the use of an independent samples t-test (α = 0.05). The suitability values by silicone rubber film slice measurement of the PEEK group were lower than those of the Co-Cr group in four types, with the differences indicating statistical significance (p < 0.05) in type one, type two, and type four. The suitability values using the three-dimensional image overlay method showed no statistical differences (p > 0.05) between the two groups in four types. The trueness values of the PEEK group were within the allowable range of clinical error. The suitability and trueness of the PEEK RPD framework fabricated by CAD-CAM technology met the requirements of the clinical prosthesis. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the in vitro study was to compare the internal merge and marginal perfection of polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) crowns under a stereomicroscope. Methods: All-ceramic preparation is done on the maxillary first premolar which is mounted on the wax block which was scanned using 3Shape scanner and duplicated into 30 acrylic CAD/CAM dies (n = 15) for the placement of PEEK and PEKK crowns. The YENADENT milling system was used to fabricate 15 samples from Group A PEEK crowns and to fabricate 15 samples from Group B PEKK crowns. According to the manufacturer's instructions, an equal amount of the dual-cure resin luting agent (Rely X U200 Self-Adhesive resin, 3M, Germany) was dispensed on the mixing pad before being mixed with cement and painted on the internal surfaces of the copings with the finger pressure crowns which were luted. The values were then analyzed using one-way ANOVA (post hoc) followed by Dunnett's t-test. Results: Among those two groups, PEEK group materials showed the lowest mean value of (28.73.3 ± 4.01) for marginal fit and (26.72 ± 2.53) for internal gap, whereas PEKK group showed a mean value of (32.85 ± 4.63) and (33.06 ± 4.14), respectively. Conclusion: Among these two groups, comparatively less marginal fit and internal adaptation is seen in PEKK when compared to the PEEK crowns. While the marginal fit and internal adaptation of both PEEK and PEKK copings were in acceptable clinical range. [ABSTRACT FROM AUTHOR]

Background: In the evolving landscape of anterior cervical discectomy and fusion (ACDF), the integration of biomechanical advancements and proper fusion-enhancing materials is crucial for optimizing patient outcomes. This case series evaluates the efficacy and clinical implications of employing zero-profile polyetheretherketone (PEEK) cages filled with biphasic calcium phosphate (BCP) in ACDF procedures, focusing on fusion and subsidence rates alongside patient disability, residual pain, and quality of life. Methods: This case series comprises 76 consecutive patients, with a median follow-up of 581 days. The Bridwell classification system was used for assessing fusion rates while subsidence occurrence was recorded, correlating these radiographic outcomes with clinical implications. Results: The results demonstrated a satisfactory fusion rate (76.4% for grades I and II). The subsidence rate was low (6.74% of segments). Significant clinical improvements were observed in pain, disability, and quality-of-life metrics, aligning with the minimum clinically important difference thresholds; however, subgroup analyses demonstrated that subsidence or pseudoarthrosis group improvement of PROMs was not statistically significant with respect to baseline. ANOVA analyses documented that subsidence has a significant weight over final follow-up pain and disability outcomes. No dysphagia cases were reported. Conclusions: These findings underscore the efficacy of zero-profile PEEK cages filled with BCP in ACDF, highlighting their potential to improve patient outcomes while minimizing complications. Pseudoarthrosis and subsidence have major implications over long-term PROMs. The study reinforces the importance of selecting appropriate surgical materials to enhance the success of ACDF procedures. [ABSTRACT FROM AUTHOR]

The occurrence of bone diseases has been increasing rapidly, in line with the aging population. A representative spinal fusion material, polyetheretherketone (PEEK), is advantageous in this regard as it can work in close proximity to the elastic modulus of cancellous bone. However, if it is used without surface modification, the initial osseointegration will be low due to lack of bioactivity, resulting in limitations in surgical treatment. In this study, we aimed to modify the surface of PEEK cages to a hydrophilic surface by coating with polyethylene glycol (PEG), hyaluronic acid (HA), and polydopamine (PDA), and to analyze whether the coated surface exhibits improved bioactivity and changes in mechanical properties for orthopedic applications. Material properties of coated samples were characterized and compared with various PEEK groups, including PEEK, PEEK-PEG, PEEK-HA, and PEEK-PDA. In an in vitro study, cell proliferation was found to be enhanced on PDA-coated PEEK; it was approximately twice as high compared to the control group. In addition, mechanical properties, including static and torsion, were not affected by the presence of the coating. Thus, the results suggest that PEEK-PDA may have the potential for clinical application in fusion surgery for spinal diseases, as it may improve the rate of osseointegration. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Successful management of cervical tuberculosis and severe kyphosis was achieved using a PEEK expandable cage and titanium plate, demonstrating favorable outcomes in restoring cervical alignment and stability. This approach represents a promising alternative for addressing complex cervical pathologies, highlighting the potential of PEEK‐based interventions in surgical management. Cervical tuberculosis can lead to severe vertebral destruction and kyphosis, posing challenges in surgical management. Recent advancements, including the use of polyetheretherketone (PEEK) expandable cages and titanium plates, show promise in addressing multilevel cervical pathologies. This report details the successful treatment of a 27‐year‐old male with cervical tuberculosis and severe kyphosis. Surgical intervention involved prevertebral abscess evacuation, C5‐C7 corpectomy, and insertion of a PEEK expandable cage with an anterior titanium plate. Postoperative care included a Philadelphia collar, and follow‐up demonstrated restored cervical alignment and stability. The use of PEEK‐based surgical interventions, as demonstrated in this case, represents a significant evolution in managing complex cervical conditions. The successful outcome highlights the potential benefits of PEEK expandable cages in addressing cervical tuberculosis and kyphosis. Further research is needed to validate these findings and establish PEEK‐based interventions as a viable alternative in such cases. [ABSTRACT FROM AUTHOR]

With the development of the shipbuilding industry, it is necessary to improve tribological properties of polyether ether ketone (PEEK) as a water-lubricated bearing material. In this study, the sulfonated PEEK (SPEEK) with three distinct chemical structures was synthesized through direct sulfonated polymerization, and high fault tolerance and a controllable sulfonation degree ensured the batch stability. The tribological and mechanical properties of SPEEK with varying side groups (methyl and tert-butyl) and rigid segments (biphenyl) were compared after sintering in a vacuum furnace. Compared to the as-made PEEK, as the highly electronegative sulfonic acid group enhanced the hydration lubrication, the friction coefficient and wear rate of SPEEK were significantly reduced by 30% and 50% at least without affecting the mechanical properties. And lower steric hindrance and entanglement between molecular chains were proposed to be partially responsible for the lowest friction behavior of SPEEK with methyl side groups, making it a promising and competitive option for water-lubricated bearings. [ABSTRACT FROM AUTHOR]

Objective: The aim of this in vitro study was to investigate microorganism adhesion and biofilm formation between pure and ceramic-reinforced polyetheretherketone (PEEK) materials. Methods: A total of 72 rectangular (8 x 8 x 4 mm) samples were prepared from pure-PEEK without filler and PEEK (Ceramicreinforced PEEK - bio high-performance polymer) containing 20% nano-ceramic filler. A profilometer contact surface measurement device was used to assess the surface roughness of the samples. PEEK groups (36 pure PEEK, 36 Ceramic-reinforced PEEK) were divided into 4 sub-groups of 9 according to the microorganism strains. Staphylococcus aureus [American Type Culture Collection (ATCC 29213)], Acinetobacter baumannii (ATCC 19606), Enterococcus faecalis (ATCC 29212), and Candida albicans (ATCC 10231) standard strains were used for microbiological analysis. Blocks were added to 24-well microplates containing suspensions of microorganisms and were incubated at 37 °C for 72 hours. Microplates were read at a wavelength of 490 nm using crystal violet. Results: No significant difference was determined between the PEEK groups in terms of surface roughness. No significant differences in biofilm formation of S. aureus, A. baummanii, E. faecalis, and C. albicans strains were found between the PEEK groups (p>0.05). In the pure-PEEK, the highest adhesion was recorded in S. aureus (p<0.001), and the lowest adhesion in C. albicans (p<0.001). In the ceramic-reinforced PEEK group, S. aureus and A. baummanii adhesions were observed more than E. faecalis and C. Albicans (p<0.001). Conclusion: The results of this investigation demonstrated no significant differences in the biofilm formation of different strains between PEEK materials. This was a preliminary study to define the biological characteristics of ceramic-reinforced PEEK. There is a need for further comparative and clinical studies on this subject. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous literature reported that the fusion cage moved more than 2 mm from its original position, which means that the fusion cage moved backward. At present, clinical observation has found that the factors leading to the displacement of the fusion cage are complex, and the relationship between these factors and the cage retropulsion is not clear. OBJECTIVE: To explore the risk factors related to cage retropulsion after lumbar interbody fusion. METHODS: Retrospective analysis was conducted in 200 patients who underwent transforaminal lumbar interbody fusion surgery with a polyetheretherketone interbody fusion from February 2020 to February 2022. According to the distance from the posterior edge of the vertebral fusion cage to the posterior edge of the vertebral body after the operation (the second day after the removal of the drainage tube) and 1, 3, 6 and 12 months after the operation, patients were [ABSTRACT FROM AUTHOR]

To compare the safety and radiological effectiveness of lumbar interbody fusion with a 3D-printed porous titanium (3D-PPT) cage versus a polyetheretherketone (PEEK) cage for the treatment of lumbar degenerative disease. This study was registered at PROSPERO (CRD42023461511). We systematically searched the PubMed, Embase, and Web of Science databases for related studies from inception to September 3, 2023. Review Manager 5.3 was used to conduct this meta-analysis. The reoperation rate, complication rate, fusion rate, and subsidence rate were assessed using relative risk and 95% confidence intervals. Ten articles reporting 9 studies comparing lumbar interbody fusion with 3D-PPT cages versus PEEK cages for the treatment of lumbar degenerative disease were included. The subsidence rate at the 1-year follow-up in the 3D-PPT cage was significantly lower than that in the PEEK cage. The fusion rate in the 3D-PPT cage was significantly higher than that in the PEEK cage at the 6-month follow-up. No significant difference was identified between the 2 groups at the 12-month follow-up. No significant difference was identified between the 2 groups in terms of the complication rate and reoperation rate. There was a trend toward a lower complication rate and reoperation rate with the 3D-PPT cage. Compared with the PEEK cage, the 3D-PPT cage may be a safer implant. The 3D-PPT cage was associated with a higher fusion rate and lower subsidence rate. The 3D-PPT cage may accelerate the intervertebral fusion process, improve the quality of fusion and prevent the occurrence of subsidence. [ABSTRACT FROM AUTHOR]

Polyetheretherketone (PEEK) has become a promising material for bone engineering due to its excellent mechanical properties, radiolucency and chemical resistance. However, its inherent bioinertness and lack of osteogenic activity induce a foreign body reaction and fibrous encapsulation, which limits its effectiveness in promoting bone regeneration. Herein, we develop a novel bioactive glass-functionalized PEEK scaffold (ADSP) to accelerate bone regeneration by immunoregulation. Strontium-doped bioactive glass nanoparticles loaded with alendronate (A-SrBG) were coated on the sulfonated PEEK scaffold by the strong adhesion ability of polydopamine. The released bioactive ions from the scaffold can improve the biocompatibilities and osteogenic activity of PEEK. In vitro results showed the ADSP scaffold promoted polarization of the M2 macrophages via the NF-κB pathway to enhance the osteogenic differentiation of rat bone mesenchymal stem cells (rBMSCs). Further, in vivo rat skull drilling model assessment revealed efficient polarization of M2 macrophage and desirable new bone formation. Thus, ADSP scaffold exerted osteoimmunomodulation effect to promote bone regeneration. [ABSTRACT FROM AUTHOR]

Carbon fiber/polyether ether ketone thermoplastic composites formed by automated fiber placement are susceptible to delamination damage. The interlaminar mechanical performance of carbon fiber/polyether ether ketone laminates can be enhanced in situ by doping carbon nanotubes in the plies. In this paper, the interfacial bonding energy between polyether ether ketone and buckypaper is analyzed by molecular dynamics. A novel method for preparing buckypaper/polyether ether ketone reinforcement materials and buckypaper/carbon fiber/polyether ether ketone multi-scale thermoplastic composites is proposed. The microstructure, crystallinity, and mechanical properties are analyzed. The results show that the polyether ether ketone resin fully penetrate the buckypaper interior and have a good interfacial bonding property. The buckypaper/polyether ether ketone composite films have a dense structure and are well-doped into the plies of carbon fiber/polyether ether ketone laminates. Compared with carbon fiber/polyether ether ketone laminates, the crystallinity, interlaminar shear strength, Model-I fracture toughness, and Model-II fracture toughness of buckypaper/carbon fiber/polyether ether ketone laminates are increased by 22.3%, 22.2%, 20%, and 9.5%, respectively. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) has excellent chemical stability, x-ray transmittance, and elastic modulus close to human cortical bone, which can effectively reduce the stress shielding effect. Therefore, PEEK can be used as a commonly used medical bone implant material to repair damaged bones. However, due to its low surface free energy, PEEK has a certain degree of biological inertness. Surface modification methods are urgently needed to improve this problem. Laser surface texturing is expected to improve the biological inertia of PEEK materials. In this study, an ultraviolet laser with a wavelength of 355 nm was used to construct textures on the surface of PEEK materials. By biomimetic design on the surface of PEEK materials, textures similar in depth and width to the surface topography of natural bones were processed. We explore the specific improvement of corrugated texture, single line texture, and orthogonal texture on PEEK material performance, aiming at improving the service performance of PEEK material and creating conditions for better service of PEEK material in vivo. Through the evaluation of PEEK surface contact angle, friction and wear properties, and biocompatibility, the research results show that laser surface texture treatment can improve many service properties of PEEK materials. [ABSTRACT FROM AUTHOR]

High-performance engineering thermoplastics offer lightweight and excellent mechanical performance in a wide temperature range. Their composites with carbon nanotubes are expected to enhance mechanical performance, while providing thermal and electrical conductivity. These are interesting attributes that may endow additional functionalities to the nanocomposites. The present work investigates the optimal conditions to prepare polyether ether ketone (PEEK)/multi-walled carbon nanotube (MWCNT) nanocomposites, minimizing the MWCNT agglomerate size while maximizing the nanocomposite electrical conductivity. The aim is to achieve PEEK/MWCNT nanocomposites that are suitable for melt-spinning of electrically conductive multifilament's. Nanocomposites were prepared with compositions ranging from 0.5 to 7 wt.% MWCNT, showing an electrical percolation threshold between 1 and 2 wt.% MWCNT (107–102 S/cm) and a rheological percolation in the same range (1 to 2 wt.% MWCNT), confirming the formation of an MWCNT network in the nanocomposite. Considering the large drop in electrical conductivity typically observed during melt-spinning and the drawing of filaments, the composition PEEK/5 wt.% MWCNT was selected for further investigation. The effect of the melt extrusion parameters, namely screw speed, temperature, and throughput, was studied by evaluating the morphology of MWCNT agglomerates, the nanocomposite rheology, and electrical properties. It was observed that the combination of the higher values of screw speed and temperature profile leads to the smaller number of MWCNT agglomerates with smaller size, albeit at a slightly lower electrical conductivity. Generally, all processing conditions tested yielded nanocomposites with electrical conductivity in the range of 0.50–0.85 S/cm. The nanocomposite processed at higher temperature and screw speed presented the lowest value of elastic modulus, perhaps owing to higher matrix degradation and lower connectivity between the agglomerates. From all the process parameters studied, the screw speed was identified to have the higher impact on nanocomposite properties. [ABSTRACT FROM AUTHOR]

Osseointegration is highly desirable for implants used for bone replacement. Polyetheretherketone (PEEK) is an attractive material due to its characteristics such as high biocompatibility and Young's modulus similar to human bones. However, PEEK is bioinert, meaning cells do not adhere and proliferate on its surface. This problem is addressed in this study, with the goal of enhancing osseointegration of additively manufactured PEEK. The influences of surface modifications and porous structures on cellular behavior were assessed by wettability and in vitro tests with subclone of the human osteosarcoma cell line‐2 osteoblasts. Overall, the combination of surface modification, type of plasma process used, atmospheric pressure versus vacuum‐based, and surface structuring, especially gyroid structures, improve the cellular proliferation on PEEK. Therefore, its ability to enhance osseointegration is highly promising. [ABSTRACT FROM AUTHOR]

Bioactive glass–ceramic (BGC) cage is a substitute for polyether ether ketone (PEEK) cages in anterior cervical discectomy and fusion (ACDF). Only a few comparative studies exist using PEEK and non-window-type BGC cages (CaO–SiO2–P2O5–B2O3) in single-level ACDF. This study compared PEEK cages filled with autologous iliac bone grafts and BGC cages regarding clinical safety and effectiveness. A retrospective case series was performed on 40 patients who underwent single-level ACDF between October 2020 and July 2021 by a single orthopedic spine surgeon. The spacers used in each ACDF were a PEEK cage with a void filled with an autologous iliac bone graft and a non-window-type BGC cage in 20 cases. The grafts were compared pre-operatively and post-operatively at 6 weeks and 3, 6, and 12 months. Post-operative complications were investigated in each group. Clinical outcome was measured, including Visual Analog Scale (VAS) scores of neck and arm pains, Japanese Orthopedic Association score (JOA), and Neck Disability Index (NDI). Dynamic lateral radiographs were used to assess the inter-spinous motion (ISM) between the fusion segment and subsidence. The fusion status was evaluated using a computed tomography (CT) scan. Overall, 39 patients (19 and 20 patients in the PEEK and BGC groups, respectively) were recruited. Eighteen (94.7%) and 19 (95.0%) patients in the PEEK and BGC groups, respectively, were fused 12 months post-operatively, as assessed by ISM in dynamic lateral radiograph and bone bridging formation proven in CT scan. The PEEK and BGC groups showed substantial improvement in neck and arm VAS, JOA, and NDI scores. No substantial difference was found in clinical and radiological outcomes between the PEEK and BGC groups. However, the operation time was considerably shorter in the BGC group than in the PEEK group. In conclusion, a non-window-type BCG cage is a feasible substitute for a PEEK cage with an autologous iliac bone graft in single-level ACDF. [ABSTRACT FROM AUTHOR]

Bioactive glass–ceramic (BGC) cage is a substitute for polyether ether ketone (PEEK) cages in anterior cervical discectomy and fusion (ACDF). Only a few comparative studies exist using PEEK and non-window-type BGC cages (CaO–SiO2–P2O5–B2O3) in single-level ACDF. This study compared PEEK cages filled with autologous iliac bone grafts and BGC cages regarding clinical safety and effectiveness. A retrospective case series was performed on 40 patients who underwent single-level ACDF between October 2020 and July 2021 by a single orthopedic spine surgeon. The spacers used in each ACDF were a PEEK cage with a void filled with an autologous iliac bone graft and a non-window-type BGC cage in 20 cases. The grafts were compared pre-operatively and post-operatively at 6 weeks and 3, 6, and 12 months. Post-operative complications were investigated in each group. Clinical outcome was measured, including Visual Analog Scale (VAS) scores of neck and arm pains, Japanese Orthopedic Association score (JOA), and Neck Disability Index (NDI). Dynamic lateral radiographs were used to assess the inter-spinous motion (ISM) between the fusion segment and subsidence. The fusion status was evaluated using a computed tomography (CT) scan. Overall, 39 patients (19 and 20 patients in the PEEK and BGC groups, respectively) were recruited. Eighteen (94.7%) and 19 (95.0%) patients in the PEEK and BGC groups, respectively, were fused 12 months post-operatively, as assessed by ISM in dynamic lateral radiograph and bone bridging formation proven in CT scan. The PEEK and BGC groups showed substantial improvement in neck and arm VAS, JOA, and NDI scores. No substantial difference was found in clinical and radiological outcomes between the PEEK and BGC groups. However, the operation time was considerably shorter in the BGC group than in the PEEK group. In conclusion, a non-window-type BCG cage is a feasible substitute for a PEEK cage with an autologous iliac bone graft in single-level ACDF. [ABSTRACT FROM AUTHOR]

Delamination due to an inferior adhesion between reinforcement material and matrix in carbon fiber-reinforced thermoplastic (CFRTP) composites is a crucial problem to be solved. To this end, this study aims to overcome poor wettability between reinforcing phase, i.e., carbon fiber (CF), and thermoplastic matrix, i.e., polyetherether ketone (PEEK). Herein, CF's surface was tailored by application of different polymeric sizing agents which have different chemical structures. Morphology and topology analyses were performed by Scanning Electron Microscope and 3D laser scanning, respectively. Later, a variety of wettability results were obtained by the sessile drop method used in Contact Angle (CA) measurements for CFs throughout application of each sizing agent applied by dip coating. Sizing materials were designed such that the chemical structure of CF's surface could exhibit compatibility with the matrix itself. Consequently, complete wettability (CA: 0°) was achieved for CFs sized by HPEEK (CF/hydroxylated PEEK (HPEEK)) and the surface free energy (SFE) of CF was enhanced from 5.43 to 72.8 mJ/m2 while the SFE of the PEEK matrix is 40.1 mJ/m2. Moreover, sizing by HPEEK improved the average surface roughness of CF by 32% which enables optimized adhesion. Afterward, repetitive tensile tests were carried out to observe effects of improved interfacial interlocking on the mechanical properties of the final CFRTP composite. Stress–strain curves revealed that the tensile strength of CFRTP improved from 473 to 508 MPa through the sizing of CF by HPEEK whereas pristine PEEK has a much smaller tensile strength (98 MPa) than the aforementioned CF-reinforced composites. The sizing of carbon fiber's surface by HPEEK resulted in an enhanced adhesion with the PEEK matrix. Since the chemical structure and physical properties of sizing agent and matrix are compatible, potential debonding between them was eliminated. Thus, the improved wettability led to a substantial increase in the mechanical strength of the final TP composite. [ABSTRACT FROM AUTHOR]

The material addition rate (MAR) of fused filament fabrication (FFF) is an indicator of process efficiency varied by process parameter settings, which affects energy consumption and part quality in FFF. This study aims to identify the optimal MAR of FFF using carbon-fiber-reinforced polyether-ether-ketone (CFR-PEEK) by considering a trade-off between energy consumption and the dimensional accuracy of FFF outputs. A design of experiments considering two main process parameters is planned to print three sample types through FFF for CFR-PEEK. Then, the MAR (i.e., deposited material volume per build time) of FFF is obtained to derive individual regression models of energy consumption and the dimensional accuracy measured for each sample type. Furthermore, a trade-off between energy consumption and dimensional accuracy on the MAR is formulated to derive an optimal MAR for each sample type. The results show that FFF for CFR-PEEK has a trade-off between energy consumption and dimensional accuracy; there exists a specific MAR that maximizes the overall performance of energy consumption and dimensional accuracy for each sample type. The optimal MAR is the highest for the small volume sample, whereas it becomes the lowest for the vertical build orientation sample. This study suggests that the optimal MAR should be flexibly adjusted based on a fabricated part. The findings from this study also address the fact that decision-making for optimal FFF operations needs a transition from the identification of specific process parameter settings to the management of a proper process efficiency level in FFF. [ABSTRACT FROM AUTHOR]

Bioactive glass–ceramic (BGC) cage is a substitute for polyether ether ketone (PEEK) cages in anterior cervical discectomy and fusion (ACDF). Only a few comparative studies exist using PEEK and non-window-type BGC cages (CaO–SiO2–P2O5–B2O3) in single-level ACDF. This study compared PEEK cages filled with autologous iliac bone grafts and BGC cages regarding clinical safety and effectiveness. A retrospective case series was performed on 40 patients who underwent single-level ACDF between October 2020 and July 2021 by a single orthopedic spine surgeon. The spacers used in each ACDF were a PEEK cage with a void filled with an autologous iliac bone graft and a non-window-type BGC cage in 20 cases. The grafts were compared pre-operatively and post-operatively at 6 weeks and 3, 6, and 12 months. Post-operative complications were investigated in each group. Clinical outcome was measured, including Visual Analog Scale (VAS) scores of neck and arm pains, Japanese Orthopedic Association score (JOA), and Neck Disability Index (NDI). Dynamic lateral radiographs were used to assess the inter-spinous motion (ISM) between the fusion segment and subsidence. The fusion status was evaluated using a computed tomography (CT) scan. Overall, 39 patients (19 and 20 patients in the PEEK and BGC groups, respectively) were recruited. Eighteen (94.7%) and 19 (95.0%) patients in the PEEK and BGC groups, respectively, were fused 12 months post-operatively, as assessed by ISM in dynamic lateral radiograph and bone bridging formation proven in CT scan. The PEEK and BGC groups showed substantial improvement in neck and arm VAS, JOA, and NDI scores. No substantial difference was found in clinical and radiological outcomes between the PEEK and BGC groups. However, the operation time was considerably shorter in the BGC group than in the PEEK group. In conclusion, a non-window-type BCG cage is a feasible substitute for a PEEK cage with an autologous iliac bone graft in single-level ACDF. [ABSTRACT FROM AUTHOR]

The membrane is a central component in the commercialization of vanadium redox flow batteries (VRFB), with Nafion being the preferred material for those membranes. Nafion suffers however from high vanadium crossover and high cost, thus limiting its wider commercial application in VRFB. To address this, studies have focused on sulfonated polyether ether ketone (SPEEK) as an alternative material. This work presents an economic study on the production costs of 3D printed SPEEK (3D‐SPEEK) membranes for VRFB, with multiple production scenarios evaluated. This analysis relies on the performances of 3D‐SPEEK membranes prepared in our laboratory, which have shown higher Coulombic efficiency and lower vanadium ions diffusion than Nafion membranes. Results from the economic analysis revealed that the cost of the 3D‐SPEEK membrane varies from 567.77 to 79.35 €/m2 depending on the production scheme and scale used. Production costs lower than commercial Nafion membranes are achieved when a large production scheme is used. Further analysis shows that 3D‐SPEEK membranes might even be cheaper than conventional SPEEK membranes if their printing time is reduced. [ABSTRACT FROM AUTHOR]

Conventional substrates for optoelectronic systems include inorganic or organic carrier materials; however, these systems are typically subjected to environmentally harmful multistep processes to prepare printed circuit boards. To mitigate these issues, the present article reports a polyether ether ketone (PEEK)‐based composite densely filled with copper microparticles, prepared using a simple, cost‐effective, and sustainable synthesis method. The material exhibits high thermal conductivity but is electrically nonconductive prior to undergoing laser treatment. To prevent the composite from exhibiting electrical conductivity, the copper particles are coated with a thin silica layer through a sol–gel reaction. The thermal stability of PEEK and the Cu–PEEK composites with Cu contents of up to 70 vol%, which are prepared via heat melding, is investigated by thermogravimetric analysis, differential scanning calorimetry, and Fourier‐transform infrared spectroscopy to clarify the manner in which copper affects the chemical structure of the polymer. The developed composite exhibits a significantly higher thermal conductivity than that of the unfilled PEEK polymer. This paper also describes the effects of laser treatment on the surface morphology. Overall, this study suggests that conductive tracks with low electrical resistance can be created on electrically insulating substrates with high thermal conductivity. [ABSTRACT FROM AUTHOR]

Among interbody implants used during anterior cervical discectomy and fusion (ACDF), structural allografts and polyetheretherketone (PEEK) are the most used spacers. Currently, no consensus has been established regarding the superiority of either implant, with US surgeons preferring structural allografts, whereas UK surgeons preferring PEEK. The purpose of this systematic review (level of evidence, 4) was to compare postoperative and patient-reported outcomes between the use of structural allografts PEEK interbody spacers during ACDF. Five electronic databases (PubMed, Embase, Scopus, Web of Science, and Cochrane) were searched for articles comparing the usage of structural allograft and PEEK interbody spacers during ACDF procedures from inception to April 10, 2023. The searches were conducted using the keywords "Spine," "Allograft," and "PEEK" and were performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Subsequent quality and sensitivity analyses were performed on the included studies. Nine studies involving 1,074 patients were included. Compared with the PEEK group, the structural allograft group had comparable rates of postoperative pseudoarthrosis (p =0.58). However, when stratified according to the number of levels treated, the 3-level ACDF PEEK group was 3.45 times more likely to have postoperative pseudoarthrosis than the structural allograft group (p =0.01). Subsequent postoperative outcomes (rate of subsidence and change in the preoperative and postoperative segmental disc heights) were comparable between the PEEK and structural allograft groups. Patient-reported outcomes (Visual Analog Scale [VAS] of neck pain and Neck Disability Index [NDI]) were comparable. This study showed that for 3-level ACDFs, the use of structural allografts may confer higher fusion rates. However, VAS neck pain, NDI, and subsidence rates were comparable between structural allografts and PEEK cages. In addition, no significant difference in pseudoarthrosis rates was found between PEEK cages and structural allografts in patients undergoing 1- and 2-level ACDFs. [ABSTRACT FROM AUTHOR]

This article discusses the use of polyetheretherketone (PEEK) cranial implants in cranioplasty procedures. The traditional method of using autologous bone flap reimplantation often leads to complications, with 50% of patients requiring implant placement due to resorption. PEEK implants, which are milled from solid PEEK blocks, offer a more design-optimized and cost-effective solution. The article presents a new software that allows surgeons to create patient-specific PEEK implants through 3D printing, reducing production time and involving the surgeon in the design process. The implementation of in-hospital PEEK implant manufacturing has the potential to benefit patients by providing rapid and cost-effective cranial implants. [Extracted from the article]

Polyetheretherketone (PEEK) is of interest as implant material for cementless tibial total knee arthroplasty (TKA) components due to its potential advantages. One main advantage is that the stiffness of PEEK closely resembles the stiffness of bone, potentially avoiding peri-prosthetic stress-shielding. When introducing a new implant material for cementless TKA designs, it is essential to study its effect on the primary fixation. The primary fixation may be influenced by patient factors such as age, gender, and body mass index (BMI). Therefore, the research objectives of this finite element (FE) study were to investigate the effect of material (PEEK vs. titanium) and patient characteristics on the primary fixation (i.e., micromotions) of a cementless tibial tray component. A total of 296 FE models of 74 tibiae were created with either PEEK or titanium material properties, under gait and squat loading conditions. Overall, the PEEK models generated larger peak micromotions than the titanium models. Differences were seen in the micromotion distributions between the PEEK and titanium models for both the gait and squat models. The micromotions of all tibial models significantly increased with BMI, while gender and age did not influence micromotions. [ABSTRACT FROM AUTHOR]

A carbon fiber‐reinforced polyetheretherketone (CFR/PEEK) hip stem with a special antibiotic elution mechanism is under development to treat periprosthetic joint infection (PJI). The antibiotic elution characteristics of intramedullary implants were experimentally investigated, and the efficacy of revision surgery using a therapeutic stem in treating ovine PJI was examined. To evaluate elution characteristics, the intramedullary vancomycin‐loaded CFR/PEEK cylindrical implants were inserted in the distal femur of nine sheep, and the vancomycin elution rate was measured at 2, 7, and 21 days. To evaluate therapeutic efficacy, the PJI model with staphylococcus aureus was attempted to create for five sheep. Moreover, the therapeutic vancomycin‐loaded CFR/PEEK stem was implanted during one‐stage revision surgery. Three weeks after revision surgery, the treatment efficacy was evaluated based on bacterial cultures and wound findings. In addition, the vancomycin elution rate from the stem was measured. On average, the cylindrical implants eluted approximately 70% vancomycin in 21 days. Of the five sheep attempting to create a PJI model, three were successfully infected with S. aureus as intended for verification of treatment efficacy. In all three joints, negative bacterial cultures and no purulence were observed 3 weeks after revision surgery. The vancomycin elution rates from the stems were >70%. Efficient elution of vancomycin was confirmed by the experimental implant inserted into the bone marrow and the stem in actual PJI treatment. Using a novel therapeutic stem with an antibiotic elution mechanism in one‐stage revision surgery, successful treatment was demonstrated in all S. aureus‐induced PJIs. [ABSTRACT FROM AUTHOR]

Background: Proton radiotherapy treatment plans are currently restricted by the range uncertainties originating from the stopping power ratio (SPR) prediction based on single‐energy computed tomography (SECT). Various studies have shown that multi‐energy CT (MECT) can reduce the range uncertainties due to medical implant materials and age‐related variations in tissue composition. None of these has directly applied the basis material density (MD) images produced by projection‐based MECT systems for SPR prediction. Purpose: To present and evaluate a novel proton SPR prediction method based on MD images from dual‐energy CT (DECT), which could reduce the range uncertainties currently associated with proton radiotherapy. Methods: A theoretical basis material decomposition into water and iodine material densities was performed for various pediatric and adult human reference tissues, as well as other non‐tissue materials, by minimizing the root‐mean‐square relative attenuation error in the energy interval from 40 to 140 keV. A model (here called MD‐SPR) mapping predicted MDs to theoretically calculated reference SPRs was created with locally weighted scatterplot smoothing (LOWESS) data‐fitting. The goodness of fit of the MD‐SPR model was evaluated for the included reference tissues. MD images of two electron density phantoms, combined to form a head‐ and an abdomen‐sized phantom setup, were acquired with a clinical projection‐based fast‐kV switching DECT scanner. The MD images were compared to the theoretically predicted MDs of the tissue surrogates and other non‐tissue materials in the phantoms, as well as used for input to the MD‐SPR model for generation of SPR images. The SPR images were subsequently compared to theoretical reference SPRs of the materials in the phantoms, as well as to SPR images from a commercial algorithm (DirectSPR, Siemens Healthineers, Forchheim, Germany) using image‐based consecutive scan DECT for the same phantom setups. Results: The predicted SPRs of the tissue surrogates were similar for MD‐SPR and DirectSPR, where the adipose and bone tissue surrogates were within 1% difference to the reference SPRs, while other non‐adipose soft tissue surrogates (breast, brain, liver, muscle) were all underestimated by between −0.7% and −1.8%. The SPRs of the non‐tissue materials (polymethyl methacrylate (PMMA), polyether ether ketone (PEEK), graphite and Teflon) were within 2.8% for MD‐SPR images, compared to 6.8% for DirectSPR. Conclusions: The MD‐SPR model performed similar compared to other published methods for the human reference tissues. The SPR prediction for tissue surrogates was similar to DirectSPR and showed potential to improve SPR prediction for non‐tissue materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Supercritical toluene was used to depolymerize e-waste thermoplastics. • STL temperature and time on depolymerization of PA, PC, POM, and PEEK were studied. • STL conversion reached 100% for PEEK but only reached 32.23% for POM. • Depolymerized PA and PC resulted in significant nitrogen containing chemicals. Solvothermal liquefaction (STL) is a thermochemical conversion technique that employs solvents other than water to transform waste plastics into valuable compounds. The objective of this study was to explore the potential use of supercritical toluene, a nonpolar solvent, for the depolymerization of four electrical waste (e-waste) thermoplastics, namely polyamide (PA), polycarbonate (PC), polyoxymethylene (POM), and polyether ether ketone (PEEK), into liquid products. Depolymerization experiments were carried out in batch reactors at three reaction temperatures (325, 350, and 375 °C), and three residence times (1, 3, and 6 h). The findings revealed that increasing STL temperature and extending the reaction time enhances the depolymerization of e-waste thermoplastics. The highest STL conversation (100 %) was observed for POM, and the lowest STL conversation (32.23 %) was observed for PEEK. Additionally, the ultimate analysis showed that the liquid product obtained from STL at 375 °C and 6 h exhibited higher heating values (HHV) within the range of 31.43 to 35.31 MJ/kg. Thermogravimetric analysis (TGA) demonstrated that the boiling point distributions of liquid products are highly dependent on thermoplastic type. Finally, the reaction mechanisms of STL for PA, PC, POM, and PEEK were proposed based on gas chromatography-mass spectrometry (GCMS) analysis. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the treatment of edentulous maxillary implants supported fixed repair, the selection of upper scaffold structure materials and the design of different distal implant implantation methods have a close influence on the long-term stability of the whole mouth implant repair. OBJECTIVE: To comprehensively explore the influence of three different materials of upper scaffold and two implant fixation designs on the biomechanics of the fixed maxillary implant repair based on the three-dimensional finite element method. METHODS: Based on the conical beam CT data of a healthy adult with normal jaws, the Mimics software was used to separate the maxillary and maxillary dentin three-dimensional solid models, and the Geomagic Studio software was used to construct the three-dimensional finite element model of denture with denture implant and fixed maxillary arch combined with specific model parameters. According to the different designs of distal implants in the maxillary posterior region, two scheme models were established. Scheme 1 (Design 1) was designed in accordance with the “All-on-4” design used in clinical practice. Two implants were vertically implanted in the bilateral incisor region of the maxilla, and the other two implants were implanted in the bilateral second premolar region at a 30° angle. In scheme 2 (Design 2), two implants were vertically implanted in the lateral incisor region of the maxilla, and two short implants were vertically implanted in the posterior region of the maxilla in the bilateral second premolar region. Three materials (titanium, zirconia and polyether ether ketone) were used to assign values to the upper scaffold structure in the two designs, and six different models were obtained. The biomechanical effects of the implant, surrounding bone tissue and the upper scaffold structure were compared and analyzed in the oblique loading direction. RESULTS AND CONCLUSION: (1) The maximum stress peaks of all models were distributed in the neck region around the posterior implant and the cortical bone under the two edentulous implant fixed restoration schemes, regardless of the material of the upper scaffold. (2) Compared with the alternative design of Design 2, which adopted vertical implantation of short implants, Design 1 showed a more ideal stress distribution on the maxilla. (3) The scaffold model constructed by polyether ether ketone material transferred higher stress to the implant and surrounding bone tissue close to the loading zone of the upper jaw bone, followed by titanium and zirconia. As for the support itself, the peak stress of the upper scaffold of polyether ether ketone was significantly lower than that of the zirconia and titanium scaffolds. Zirconia scaffolds were used among the three upper scaffolds to disperse the stress distribution of implant and bone tissue. (4) The results suggest that both designs can be applied to clinical practice. However, from the perspective of biomechanics, the stress distribution of the implant, surrounding bone tissue and upper scaffold in Design 1 is more rational, which is more conducive to the long-term prognosis of fixed implant repair in patients with edentulous jaws. The upper scaffold material has a certain influence on the stress distribution of the implant-bone interface. [ABSTRACT FROM AUTHOR]

The light‐weight, high‐strength polyether‐ether‐ketone (PEEK) shows great potential for weight‐sensitive, load‐bearing applications. The adoption of PEEK in those applications has been accelerated by the recently emerged three‐dimensional printing (3D‐printing) technique. However, achieving high strength in the 3D‐printed PEEK is still challenging. In this study, the mechanical strength of the 3D‐printed PEEK is jointly reinforced with high‐loading carbon fibers (CFs) and annealing treatment. The PEEK‐CF composite filaments containing three different CF contents, ranging between 5 and 15 wt%, are first prepared in‐house and subsequently printed into specimens. Both the tensile and flexural tests show that the composite containing 10 wt% CF exhibits the highest strength, reaching 114.7 and 139.2 MPa, respectively, the tensile strength of which amounts to a 35% increase from the unfilled counterpart. The annealing treatment on the printed samples further increases the strength of the composite both at room temperature and high‐temperature. After annealing, the tensile strength of the 3D‐printed PEEK‐CF composite reaches 131.5 MPa at room temperature and over 60 MPa at 200°C. The results from this study can spur new insights into design advanced polymer composites with outstanding mechanical properties. Highlights: Custom‐made PEEK‐CF composite filaments with high CF content, up to 15 wt%3D‐printed PEEK‐CF composites exhibit very high tensile strength, reaching 115 MPa.The annealing treatment further strengthens the printed composite, up to 131 MPa.The jointly strengthened PEEK‐CF composite remains strong at elevated temperatures. [ABSTRACT FROM AUTHOR]

This study aims to address the challenges associated with conventional metallic bone fixation plates in biomechanical applications, such as stainless steel and titanium alloys, including stress shielding, allergic reactions, corrosion resistance, and interference with medical imaging. The use of materials with a low elastic modulus is regarded as an effective approach to overcome these problems. In this study, the impact of different types of chopped carbon fiber-reinforced polyether ether ketone (CCF/PEEK) functionally graded material (FGM) bone plates on stress shielding under static and instantaneous dynamic loading was explored using finite element analysis (FEA). The FGM bone plate models were established using ABAQUS and the user's subroutine USDFLD and VUSDFLD, and each model was established with an equivalent overall elastic modulus and distinctive distributions. The results revealed that all FGM bone plates exhibited lower stress shielding effects compared to metal bone plates. Particularly, the FGM plate with an elastic modulus gradually increased from the centre to both sides and provided maximum stress stimulation and the most uniform stress distribution within the fractured area. These findings offer crucial insights for designing implantable medical devices that possess enhanced mechanical adaptability. [ABSTRACT FROM AUTHOR]

Additive manufacturing allows for the production of complex components using various types of materials such as plastics, metals and ceramics without the need for molding tools. In the field of high-performance polymers, semi-crystalline polymers such as polyetheretherketone (PEEK) or amorphous polymers such as polyetherimide (PEI) are already successfully applied. Contrary to semi-crystalline and amorphous polymers, thermotropic liquid crystalline polymers (LCPs) do not change into an isotropic liquid during melting. Instead, they possess anisotropic properties in their liquid phase. Within the scope of this work, this special group of polymers was investigated with regard to its suitability for processing by means of fused filament fabrication. Using an LCP with a low melting temperature of around 280 °C is compared to processing an LCP that exhibits a high melting temperature around 330 °C. In doing so, it was revealed that the achievable mechanical properties strongly depend on the process parameters such as the direction of deposition, printing temperature, printing speed and layer height. At a layer height of 0.10 mm, a Young's modulus of 27.3 GPa was achieved. Moreover, by employing an annealing step after the printing process, the tensile strength could be increased up to 406 MPa at a layer height of 0.15 mm. Regarding the general suitability for FFF as well as the achieved uniaxial mechanical properties, the LCP with a low melting temperature was advantageous compared to the LCP with a high melting temperature. [ABSTRACT FROM AUTHOR]

The latest generation of high-temperature 3D printers enables the production of complex structural components from aerospace-grade thermoplastics such as PEEK (polyether ether ketone). However, adding long or continuous fibres is currently limited, and thermal stresses introduced during the process restrict the maximum part dimensions. Combining 3D-printed components with continuous fibre-reinforced components into one hybrid structure has the potential to overcome such limitations. This work aims to determine whether in situ bonding between PEEK laminates and PEEK 3D printing during overprinting is feasible and which process parameters are significantly responsible for the bonding quality. To this end, the bonding is analysed experimentally in two steps. Firstly, the influence of the process parameters on the thermal history and the strength of the bond is investigated. In the second step, a detailed investigation of the most critical parameters is carried out. The investigation showed the feasibility of overprinting with bonding strengths of up to 15 MPa. It was shown that the bonding strength depends primarily on the temperature in the interface. Additionally, the critical parameters to control the process were identified. The process influences that were displayed form the basis for future hybrid component and process designs. [ABSTRACT FROM AUTHOR]

In order to design an involute spline made of PEEK (polyetheretherketone)-based material with better performance and improve the design rules of involute splines, initially, an involute splines design theory for PEEK (polyetheretherketone)-based materials is presented, which combines international standards (ISO 4156, 1. 2. 3, 2005), American standards (ANSI B92.2M. 1989), and traditional empirical formulas. Second, using the involute splines calibration method in international standards as a guide, we developed the involute splines calibration method for PEEK-based materials by estimating the impact of energy consumption caused by viscoelasticity on temperature field calibration. Next, the contact characteristics of the designed spline were analyzed using ABAQUS2022 software to confirm the accuracy and reliability of the design and calibration methods. Finally, finite element simulation was used to analyze the influence of different pressure angles, moduli, combined lengths, and other parameters on the contact characteristics of the spline in order to realize the optimal design of PEEK-based material involute splines, to offer a theoretical foundation and improved design methodology for cylindrical straight-tooth involute splines. [ABSTRACT FROM AUTHOR]

BACKGROUND: Polyetheretherketone (PEEK) is a polyaromatic semi-crystalline thermoplastic polymer with mechanical and lubrication properties favorable for biomedical applications. Despite of its aesthetic appearance, ceramic brackets are unsatisfactory in brittleness and thickness, while PEEK is a potential material for aesthetic orthodontic brackets. OBJECTIVE: To fabricate a novel aesthetic orthodontic bracket and evaluate friction properties of PEEK and stainless steel wires. METHODS: All polyether ether ketone (PEEK) and ceramic samples disks were made into disks (diameter, 5 mm; thickness, 2 mm). The tested surfaces of PEEK were ground with #600, #800 and #1200 SiC papers, followed by polishing with Sof-Lex kit (3M ESPE, USA). The surface roughness was tested using a laser profilometer device (VK-X200, Keyence, Japan). The COFs of the specimens and stainless steel (SS) archwires were tested using a Universal Micro-Tribotester (UMT-3, Bruker, USA). The wear scratches on the materials' surfaces were examined by using a scanning electron microscope (SEM) (Hitachi SU8010). The elastic modulus and hardness of samples were examined with a nano-indenter (XP, Keysight Technologies, USA). RESULTS: The mean surface roughness of PEEK and Ceramic are 0.320 ± 0.028 μ m and 0.343 ± 0.044 μ m, respectively. PEEK has a lower Friction coefficient than Ceramic and the difference between the two groups was statistically significant (P < 0.05). The abrasive wear of Ceramic was the main wear style and was characterized by the observation of chipping fractures, while PEEK surface looked smooth without obvious scale-like desquamations and granular debris, indicating adhesive wear. CONCLUSION: Within the limitations of the present study, PEEK shows lower coefficient of friction than ceramic. PEEK has excellent properties such as low friction coefficient, smooth surface and good mechanical properties, and thus meets the requirements for orthodontic brackets. It is considered as a potential bracket material with both low friction and aesthetic performance. [ABSTRACT FROM AUTHOR]

Achieving good dispersion of graphene (GNP), in polyetheretherketone (PEEK), is challenging due to the high melt viscosity, solvent resistance and processing temperature of PEEK. In addition, certain manufacturing processes tend to enhance the anisotropy due to GNP orientation within the structure. This study investigated the fabrication of nanocomposite parts through hot compression moulding (C-MOULD) and powder bed fusion (PBF) processes, using powder with GNPs fused to the surface of polymeric particles, through a process called mechanofusion. The method applies mechanical forces of compression, shear and impact to generate a mechanical bond between materials, in this case, O2 functionalised GNP and a developmental polyaryletherketones (PAEK) grade powder. The novelty of this work is in the combination of processes used for manufacturing (material preparation and actual manufacturing processes), which are scalable and efficient in comparison with existing methods (such as solvent mixing or melt-compounding). The mechanofusion GNP-PAEK composite powders were successfully printed for the first time using the EOS P800 system with notable improvements in electrical and mechanical properties. This study highlights that the mechanofusion process could be used as an efficient process for making multifunctional nanocomposite materials and this can be combined with additive manufacturing (AM) processes to produce complex components. [ABSTRACT FROM AUTHOR]