Polyetheretherketone Research Articles

Structural Allograft versus Polyetheretherketone Cage in Anterior Cervical Discectomy and Fusion: A Meta-Analysis

Polyetheretherketone (PEEK) cages and structural allografts (SAs) are commonly used in Anterior Cervical Discectomy and Fusion (ACDF), yet their postoperative results remain uncertain. This meta-analysis was conducted to determine whether there were any differences in outcomes between patients who received these two grafts in ACDF. We comprehensively searched electronic databases up to August 2023. Observational studies or randomized controlled trials reported postoperative outcomes, including fusion, subsidence, reoperation rates, and patient-reported outcomes through the Neck Disability Index (NDI), the Visual Analog Scale (VAS) for neck and arm pain, and the Japanese Orthopedic Association (JOA)/modified JOA score following primary ACDF using SA or PEEK cage. The results are presented in odds ratios (ORs) or mean differences with corresponding 95% confidence intervals (CIs). Eleven studies were included, with 1213 patients (788 receiving SAs and 425 receiving PEEK cages). Patients having SA had significantly higher fusion (OR: 1.84, 95% CI: 1.27-2.67, p = 0.001) and lower subsidence (OR: 0.50, 95%CI: 0.30-0.86, p = 0.01) rates when compared with the PEEK cage. There was no difference in revision rate between SA or PEEK cage (p = 0.88). Two grafts demonstrated similar clinical improvements in NDI (p = 0.31), VAS for the neck (p = 0.77) and arm pain (p = 0.22), and JOA/mJOA score (p = 0.99). SA demonstrates better fusion and lower subsidence rates than the PEEK cage in ACDF. Nevertheless, these two cages resulted in equally successful postoperative clinical performances.

Evaluation of Stress Distribution in Implant Retained Fixed Prostheses Fabricated from Polyetheretherketone (PEEK) and Zirconia by CAD/CAM Technology (An in-Vitro Study)

Evaluation of Stress Distribution in Implant Retained Fixed Prostheses Fabricated from Polyetheretherketone (PEEK) and Zirconia by CAD/CAM Technology (An in-Vitro Study)

Rare earth europium recovery using selective metal-organic framework incorporated mixed-matrix membrane

Rare-earth elements (REEs) play a crucial role in state-of-the-art technologies and sustainable energy generation. However, conventional production methods of REE often instigate detrimental impacts on environment. Hence, the development of efficient and sustainable hydrometallurgical methods for REE recovery from complex solution has become a crucial research focus. This study investigates a mixed-matrix membrane composed of a highly europium selective metal-organic framework-based adsorbent, Cr-MIL-PMIDA, embedded in sulfonated poly(ether ketone) (SPEK) polymer membrane matrix to preferentially concentrate europium (Eu3+) ions in the presence of other competing cations. The activated membrane notably reduced ionic conductivity for Eu3+ compared to other multivalent ions. Membrane extraction experiments further confirmed the selective behavior, demonstrating slower diffusion for Eu3+ compared to Mg2+ and Zn2+ cations. Especially, at pH 5, Mg2⁺ and Zn2⁺ recovery was greater than 30%, whereas Eu³⁺ recovery remained lower than 4%. We propose that the strong chemical affinity between the phosphate group and Eu3+ help partition of the Eu3+ ions in the membrane phase and inhibit the diffusion and further partitioning of the Eu3+ ion from bulk solution. Furthermore, we demonstrate the stability of the composite membrane and the embedded MOF particles in aqueous solution for up to 12 days without degradation, attributing it to the robust chemical stability of the MOF structure.

Effect of stacking pattern of multilayered polyetheretherketone/boron nitride composites on the mechanical and thermal properties: Experiments and molecular dynamics simulations

The effect of stacking patterns in multilayered polyetheretherketone (PEEK)/boron nitride (BN) composites was investigated to improve the thermal conductivity and mechanical properties. The thick PEEK and BN layers in the multilayered composite were the best multilayer structure, resulting in high mechanical properties and in-plane thermal conductivity due to the many strong electrostatic interaction sites between boron nitride nanosheets (BNNSs). Molecular dynamics simulations were used to clarify the enhanced mechanism of multilayered structure on thermal conductivity. The multilayered structure with combinations of PEEKs and thick BN layers composed of large BNNSs led to the optimization of heat transfer due to the effective phonon transfer path. The best multilayered composite had the highest in-plane thermal conductivity, which was 471% higher than that of a PEEK. This study provides information about the filler size and stacking patterns for more effective multilayer structures with polymer and filler layers to achieve high performance on mechanical and thermal properties.

Effects of Covid-19 Preoperative Mouthrinses and Different Beverages and on Surface Alteration of Polyetheretherketone (PEEK)

Objectives: to compare the color change and surface roughness of polyetheretherketones (PEEK) immersed in various beverages and mouthrinses for 7 days. Methods: the specimens were divided into 6 groups, 10 pieces per group, and each group was immersed in different solutions as followed: coffee, cola, red wine, distilled water, 0.5% povidone iodine, and 1% hydrogen peroxide. A color change (∆E*ab) was measured in each sample before and after 7 days of immersion in different solutions. At a significance level of 0.05, color change data were analyzed using one-way ANOVA and pairwise comparisons with the Games-Howell method, and surface roughness changes were analyzed using the Wilcoxon Sign-Rank test. Results: immersion of PEEK in 0.5% povidone iodine caused the most color change, followed by red wine when continuously immersed for 7 days. However, immersion in different types of solutions did not affect the surface roughness of PEEK. Conclusions: After 7 days of immersion, 0.5% povidone iodine and red wine caused color change in PEEK with no change in surface roughness

Materials Evolution in Dental Implantology: A Comprehensive Review

This comprehensive review navigates the dynamic landscape of dental implant materials, exploring historical milestones, mechanical intricacies, and emerging innovations. Tracing the evolution from early experimentation to the establishment of titanium as a benchmark, the review sheds light on the critical interplay of strength, elasticity, and fatigue resistance in materials' biomechanical performance. The diverse array of materials, including metals like titanium, ceramics such as zirconia, and polymers like polyetheretherketone (PEEK), is examined in depth, emphasizing their unique attributes and contributions to clinical needs. Surface modifications emerge as transformative elements, accentuating the role of precision engineering in optimizing implant performance. Challenges, encompassing biocompatibility, mechanical incongruity, and infection vulnerabilities, underscore the intricacies of material selection in implant dentistry. The ongoing pursuit of solutions to esthetic limitations and long-term stability constitutes a focal point for future research. Emphasizing the importance of ongoing research, the review highlights emerging materials, such as bioactive ceramics and advanced polymer composites, driven by nanotechnology and 3D printing. Smart implants, antimicrobial surfaces, and regenerative approaches signal a transformative era in precision dentistry. The journey towards refined materials transcends disciplines, uniting researchers, clinicians, and materials scientists in a collaborative pursuit. As the narrative of dental implant materials unfolds, the future beckons with promises of seamless integration with biological tissues, esthetic advancements, and redefined standards in oral rehabilitation. This review encapsulates a dynamic field in continual evolution, extending an invitation to collectively shape the future of dental implantology.

Engineering Ga-doped mesoporous bioactive glass-integrated PEEK implants for immunomodulatory and enhanced osseointegration effects

With the increasing aging population, the demand for orthopedic implants is also growing. Polyether ether ketone (PEEK) is considered a promising material for orthopedic implants due to its excellent biocompatibility. However, the lack of bioactivity and excessive immune response post-implantation often impair bone integration. Therefore, it is urgent to bio-functionalize PEEK-based implants to promote bone integration. This study employs a simple, economical, and feasible method to coat Ga-ion doped bioactive glass nanoparticles (Ga-MBGs) onto sulfonated PEEK surfaces, constructing a multifunctional PEEK-based orthopedic implant. The resulting bio-functionalized PEEK implants promote macrophage M2 phenotype polarization, thus fostering an anti-inflammatory immune microenvironment. Moreover, the direct osteogenic effect of Ga ions and the immuno-osteogenic effect through promoting macrophage M2 polarization enhance osteogenic differentiation potential in vitro and bone integration in vivo. A sequence of in vivo and in vitro experiments substantiates the essential and intricate function of this innovative orthopedic implants. in regulating normal bone immunity and metabolism. Overall, the application of Ga-MBGs provides a simple, economical, and effective method for developing multifunctional orthopedic implants. This surface bio-functionalized PEEK implant, capable of modulating immunity and bone metabolism, holds significant clinical application potential as an orthopedic implant.

Preparation of modified atmosphere and moisture packaging membranes by blending quaternized polyether ether ketone with polyvinylidene fluoride and its application in grape packaging

The modified atmosphere and moisture packaging membranes for preserving Vitis vinifera L. (V. vinifera) were developed by blending triethylamine-grafted quaternized polyether ether ketone (QPEEK) and polyvinylidene fluoride (PVDF) using thermally induced phase separation. With the addition of QPEEK, the blend membranes exhibited increased hydrophilicity, gas transmission rate, and gas permeability coefficient. For the 5 % QPEEK/PVDF membrane, the water vapor transmission rate is 48.4 g/(m²·24 h), the water contact angle is 82.2°, and the CO2/O2 separation coefficient is 2.06. Compared to other groups, this membrane exhibits better tensile, swelling, and relaxation properties. These properties facilitate achieving dynamic air equilibrium within 3 days, maintaining a suitable atmosphere inside the package (3.4–4.1 % CO2 and 16.1–18.1 % O2), and timely removing moisture to prevent water vapor condensation, thus extending the shelf life of grapes to more than 25 days. Grapes packaged in 5 % QPEEK/PVDF membrane box maintained 99.3 % mass, 85.1 % firmness, and 72.2 % total phenol content, and exhibited minimal changes in soluble solids, relative electrical conductivity, and water state and distribution compared to fresh grapes. These experimental results suggest significant potential for the use of QPEEK/PVDF membranes in fruit and vegetable packaging.

Dodging reality, striking the virtual: An undulating strategy for effectively enhancing CF/PEEK interfacial adhesion!

The design of carbon fiber (CF)-reinforced polyetheretherketone (PEEK) composite materials with suitable interfaces has consistently been challenging. In this study, we sulfonated poly (phthalazinone ether sulfone ketone) (PPESK) and PEEK to prepare water-soluble SPPESK and SPEEK. Subsequently, we prepared a water-soluble sizing agent (SPPESK/SPEEK) via a straightforward blending process. This sizing agent tended to accumulate randomly on the surfaces of CFs, forming a thin film with a heterogeneous structure in the nanoscale. At the molding temperature of the composite material, the two components on the fiber surface exhibited different rheological behaviors, with PEEK preferentially infiltrating the SPEEK region, forming strong molecular entanglements. Meanwhile, the SPPESK region provided a rigid supportive structure, offering the potential for the mechanical interlocking of PEEK in the interface layer. The performance of the prepared composite materials was significantly enhanced, with their interlaminar shear strength and flexural strength reaching 87.1 MPa and 975.8 MPa, respectively. With respect to those of commercial fiber-reinforced PEEK composites, an 89.8 % increase in interlaminar shear strength and a 79.39 % increase in flexural strength were observed. This interface reinforcement mechanism presents a universally applicable strategy for the future development of fiber-reinforced composite materials.

Poly(ether ketone ketone)/hollow silica filler substrates and application for sixth generation communication

AbstractThe influence of density and shape of hollow silicas (silica hollow tubes (SHT) or hollow glass microspheres (HGM)) on dielectric and heat‐resisting characteristics of poly(ether ketone ketone) (PEKK)/SHT and PEKK/HGM films was systematically investigated. The dielectric characteristics of PEKK/SHT or PEKK/HGM films decrease to a minimum, as their SHT or HGM contents approach 8 or 20 wt%, respectively, and the minimum dielectric constant (εr) and dielectric loss (tan δ) of PEKK/SHT or PEKK/HGM films decrease visibly with decreasing SHT densities. By filling with 0.46 g cm−3 mean density of SHT or HGM fillers, the minimum εr and tan δ of PEKK/SHT films are somewhat smaller than those of PEKK/HGM films. The linear coefficient of thermal expansion (LCTE) values of PEKK/SHT or PEKK/HGM films reduce and their onset degradation temperature values increase gradually with increasing SHT and HGM contents. Low εr/tan δ (2.11/0.0022 and 2.2/0.0027 at 1 MHz), LCTE (35.5 × 10−6 and 31.2 × 10−6 °C−1) and excellent heat‐resisting properties favorable for sixth generation (6G) ultrarapid communication are realized for appropriately prepared PEKK/SHT and PEKK/HGM substrate films. The free‐volume‐hole characteristics of PEKK/HGM or PEKK/SHT films approach a maximum as SHT or HGM contents reach an optimum value of 8 or 20 wt%, respectively. © 2024 Society of Chemical Industry.

Evaluation of the forces applied by rubber dam clamps on mandibular first molar teeth with different endodontic access cavities: a 3D FEA study.

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. 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. 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. 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.

Electrospinning of polyetherketoneketone fibers: The effect of fabrication regime on the morphology, physico-chemical and biological characteristics

Electrospinning is a unique technology based on the fabrication of polymer fibers from the solution under an applied electric field. Electrospun membranes are applied in various fields, starting from filter technologies to tissue engineering. Polyalyletherketones (PAEK) is a family of synthetic bioinert polymers characterized by outstanding mechanical performance, high chemical stability, and biocompatibility. In the present study, the effect of electrospinning parameters (collector-to-tip distance, applied voltage, spinning solution flow rate and polymer concentration in the spinning solution) on the morphology of the fabricated polyetherketoneketone (PEKK) membranes as well as their crystal structure, chemical stability and biocompatibility was investigated. Based on 108 combinations of the electrospinning parameters, it was found that minimum concentration of PEKK in the spinning solution in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) required for the fibers’ formation is 4 wt %, while the applied voltage providing fibers without defects was found at 20 kV. It was demonstrated that the tested electrospinning regimes allow to fabricate the membranes with average fiber diameter from 0.76 ± 0.29 to 1.46 ± 0.60 μm and porosity from 87 ± 1 to 92 ± 1 %. It was found that electrospinning process has no effect on the chemical structure of PEKK macromolecules. Electrospinning parameters had no effect on crystal structure of PEKK in the fabricated membranes, which was found to be amorphous. The fabricated membranes demonstrated high Young modulus (above 150 MPa) and elongation over 170 %, were stable in strong alkali and acid solutions and biocompatible towards mouse embryonic fibroblasts.

Lubrication of polyphthalamide (PPA) and polyetheretherketone (PEEK) with biodegradable synthetic esters: Effects of base oil polarity, temperature and polymer aging

This study aims to evaluate the tribological behavior of polyphthalamide (PPA) and polyetheretherketone (PEEK) lubricated with biodegradable synthetic esters. Tribological tests were performed at 23 °C and 100 °C with new and aged samples to assess the effects of increased temperature and polymer aging on friction and wear. The results of tests at room temperature and the SEM images of the wear scars show that synthetic esters provide better wear resistance to PEEK than synthetic mineral oil (polyalphaolefin, PAO). FTIR and XPS analyses suggest the formation of a physisorbed protective film by the esters. Trimethylolpropane-based ester (TMP) was shown to adsorb better to both polymers than propylene glycol-based ester (PG), but this did not translate into a better tribological performance. When compared to room temperature, tests at 100 °C showed a higher wear coefficient for both polymers, irrespective of the oil. However, the friction coefficient increased for PEEK due to a higher adhesion, while it decreased for PPA because of the material’s softening. The aging of samples at 100 °C degraded the tribological performance of the polymers, especially aging in PG ester, which caused an increase in friction for PEEK and an increase in friction and wear for PPA. PG ester was found to have caused oxidation of both polymers to a greater extent than PAO or TMP ester.

A systematic review of the process parameters, mechanical characteristics and applications of polyether ether ketone (PEEK) and its composites by additive manufacturing

Abstract Additive manufacturing (AM) provides an innovative and reliable method of developing medical products with anatomically relevant geometry and mechanical performance, underscoring its significant potential in the medical field. The design of fused deposition modelling (FDM) parameters has a significant impact on the characteristics of the product fabricated utilizing FDM. Numerous studies have assessed the impact of various FDM process parameters on enhancing the print quality attributes of manufactured components, such as mechanical characteristics, production times, dimensional accuracy, and surface finish. Because of the complex features of the FDM process and the contradicting process parameters, the advancement has been slow and poorly coordinated. This work intends to provide a complete review of recent research on PEEK and CF-PEEK printed parts, where the effect of process factors on tensile strength has been described. Furthermore, PEEK, with its potential applications in medical, aerospace, and chemical sectors, serves as an inspiring material for future innovations, offering a promising outlook.

Fumasep FAA-3-PK-130: Exploiting multinuclear solid-state NMR to shed light on undisclosed structural properties

Fumasep FAA-3-PK-130 is considered the state-of-the-art among the different commercially available Anion Exchange Membranes (AEMs). It is produced by Fumatech GmbH as a cost-effective blend of polyetheretherketone (PEEK) and poly (phenylene oxide) (PPO) characterized by high hydroxyl ions conductivity, high thermal and chemical resistance, and high dimensional stability. Nevertheless, the chemical structure of the anion exchange sites and their contents were unknown so far.In this paper, we report a detailed structural characterization of Fumasep FAA-3-PK-130 to identify the material phase composition, the nature of the conducting moieties and their interactions with the adsorbed water molecules. A complete phase segregation between PPO and PEEK was found on a micrometric scale from 1H spin-lattice relaxation times and micro-ATR analysis. Multinuclear (1H, 13C, 19F) Solid-State NMR spectra, combined with nuclear spin relaxation measurements, allowed us to identify the anion exchange moiety with benzyl-ethyl-dimethylammonium. This is present as functionalizing group of PPO monomers with a functionalization degree of about 40 %. Moreover, the mobility of water absorbed in the membrane was studied by 2H Solid-State NMR on samples hydrated with deuterated water under controlled relative humidity: at low relative moisture, two different types of environments were found for water molecules, compatible with two types of water-ion clusters, one of which contains water molecules with a restricted mobility, limited to C2 jumps, due to strong interactions with ions.

The effect of surface treatments on the bond strength of polyetheretherketone posts: a systematic review protocol

Abstract* Background Polyetheretherketone (PEEK) is widely used in the biomedical field due to its outstanding biological and mechanical properties. Originally employed as a temporary abutment in implantology, recent research has expanded its indications for more definitive applications, such as frameworks and dental post and core. This shift requires a thorough assessment of PEEK’s adhesion and mechanical characteristics. However, PEEK’s inert properties and intricate chemistry create difficulties in surface treatment, resulting in reduced surface energy and inadequate adhesion. Inducing specific physical and chemical changes aims to overcome these challenges and enhance adhesion for PEEK. Despite its numerous clinical trials, standardized protocols remain lacking. This systematic review aims to assess the impact of surface treatments on the bonding performance of PEEK posts. Methods A detailed search of the literature will be conducted across several databases including PubMed, Scopus and clinical trial registries. Additional databases such as Cochrane Central, EMBASE, Web of Science and EBSCO will also be included. The search strategy will target controlled randomized studies and non-randomized clinical trials evaluating the impact of surface treatments on PEEK post adhesion strength. The Newcastle-Ottawa Scale (NOS) will be used to assess bias in non-randomized studies, while the Cochrane Risk of Bias (ROB II) tool will be employed for evaluating randomized controlled trials. Data extraction will focus on study design, treatment methods, outcomes and results. This systematic review protocol will adhere to the guidelines for systematic reviews outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Discussion The discussion will explore the implications of findings on clinical practice, highlighting the importance of enhancing PEEK’s bioactivity and surface energy to improve bonding efficacy in dental procedures. Moreover, it will suggest areas for future research to advance dental materials science, aiming to optimize the utilization of PEEK in dental applications Systematic review registration PROSPERO: CRD42024529783 (Registered on 08/04/2024).

Robust flexible hollow racetrack-shaped terahertz waveguide with single-polarization single-mode and low-loss by plasma aided hot-pressing method

A flexible single-polarization single-mode (SPSM) polymer/Ag-coated hollow waveguide with a racetrack-shaped cross-section was designed and prepared using a simple hot-pressing method and plasma treatment. The waveguide structural parameters were numerically optimized using the finite element method and the SPSM transmission can be achieved in a high birefringent (>0.8) hollow racetrack-shaped waveguide (HRW). The racetrack-like waveguides were facilely prepared by hot-pressing commercially available circular acrylonitrile butadiene styrene (ABS) and poly-ether-ether-ketone (PEEK) tubing, followed by plasma treatment and silver-plating. The HRW samples with a length of 40 cm were prepared, with a straight transmission loss of 1.74 and 1.68 dB/m at 0.1 THz, respectively, and the polarization degree is 99.9 %. When bent for 120° at a 10 cm radius or twisted by 90°, the waveguide samples have additional losses less than 0.22 and 0.14 dB/m, respectively, while the polarization degrees keep almost unchanged. After 200 h hydrothermal aging (85 RH%, 85 ℃) and 20 times high (85 ℃)/low (−40 ℃) temperature tests, the loss increase is less than 0.14 dB/m and the polarization degree remains unaffected. The HRW could be used in practice as a competitive substitute for traditional rectangular metal waveguides due to its high SPSM performance, lightweight, robustness, flexibility, and easy fabrication.

High-performance thermoplastic nanocomposites for aerospace applications: A review of synthesis, production, and analysis

Thermoset polymers are cured under natural or synthetic created conditions and retain their solid form when exposed to heat. Unlike thermosets, thermoplastics melt when exposed to heat after production. Thermoplastics are preferred as raw materials because they can be easily shaped after production, have a high shelf life and are recyclable. In this regard, the prominence of high-performance engineering polymers in recent years has led to the preference of alternative polymers to thermosets. High-performance engineering thermoplastics include thermoplastics such as polyphenylene-sulfide (PPS), polyether-ether-ketone (PEEK), polyether-ketone-ketone (PEKK), polyphenylene-ether, polysulfone,polyoxadiazole, polyimide, polyether-amide, polyether-amide-imide, polynaphthalene, and polyamide-imide. These polymers exhibit application potential in aerospace, defense, automotive, marine, energy, and medical sectors. In challenging conditions such as high pressure, temperature, and corrosive environments, they possess high service temperatures, enhanced mechanical and physical properties, preferable chemical resistance as well as out-of-autoclave and rapid processing properties. In this review article, nanomaterial production methods (bottom-up and top-bottom) are mentioned. In the following sections, PPS, PEEK, and PEKK thermoplastics are explained, and carbon- and boron-based nano additives used in constructing nanocomposites are investigated. In the last section, PPS, PEKK, and PEEK polymer nanocomposites are investigated.

Biofilm formation of Staphylococcus aureus on various implants used for surgical treatment of destructive spondylodiscitis

The incidence of spondylodiscitis has witnessed a significant increase in recent decades. Surgical intervention becomes necessary in case of bone destruction to remove infected tissue and restore spinal stability, often involving the implantation of a cage. Despite appropriate treatment, relapses occur in up to 20 percent of cases, resulting in substantial economic and social burdens. The formation of biofilm has been identified as a major contributor to relapse development. Currently, there is no consensus among German-speaking spinal surgeons or in the existing literature regarding the preferred choice of material to minimize relapse rates. Thus, the objective of this study is to investigate whether certain materials used in spinal implants exhibit varying degrees of susceptibility to bacterial attachment, thereby providing valuable insights for improving treatment outcomes.Eight cages of each PEEK, titanium-coated PEEK (Ti-PEEK), titanium (Ti), polyetherketoneketone (PEKK), tantalum (Ta) and antibiotic-loaded bone cement were incubated with 20% human plasma for 24 h. Subsequently, four implants were incubated with S. aureus for 24 h or 48 h each. The biofilm was then removed by sonication and the attained solution plated for Colony Forming Units (CFU) counting. Scanning electron microscopy was used to confirm bacterial attachment. The CFUs have been compared directly and in relation to the cages surface area. The surface area of the implants was PEEK 557 mm2, Ti-PEEK 472 mm2, Ti 985 mm2, PEKK 594 mm2, Ta 706 mm2, bone cement 123 mm2. The mean CFU count per implant and per mm2 surface area after 24 h and after 48 h was calculated. Bone cement was found to have significantly more CFUs per mm2 surface area than the other materials tested. When comparing the CFU count per implant, bone cement was statistically significantly more prone to biofilm formation than PEEK after 48 h. There was no statistical significance between the other materials when comparing both CFU count per mm2 surface area and CFU count per implant. The electron microscopic analysis showed the attachment of the bacteria, as well as production of extracellular polymeric substances (EPS) as a sign for beginning biofilm formation. Antibiotic-loaded bone cement has shown statistically significantly more bacterial attachment than the other examined materials. No difference was found between the other materials regarding bacterial attachment after 24 h and 48 h. Proposed hypotheses for further studies include testing whether differences become apparent after longer incubation or with different pathogens involved in the pathogenesis of pyogenic spondylodiscitis.

Surface Treatment of Additively Manufactured Polyetheretherketone (PEEK) by Centrifugal Disc Finishing Process: Identification of the Key Parameters.

Polyetheretherketone is a promising material for implants due to its good mechanical properties and excellent biocompatibility. Its accessibility to a wide range of applications is facilitated by the ability to process it with an easy-to-use manufacturing process such as fused filament fabrication. The elimination of disadvantages associated with the manufacturing process, such as a poor surface quality, is a main challenge to deal with. As part of the mass finishing process, centrifugal disc finishing has demonstrated good results in surface optimization, making it a promising candidate for the post-processing of additively manufactured parts. The objective of this study is to identify the key parameters of the centrifugal disc finishing process on the waviness of additively manufactured PEEK specimens, which has not been investigated previously. The waviness of the specimen was investigated by means of confocal laser scanning microscopy (CLSM), while weight loss was additionally tracked. Six parameters were investigated: type, amount and speed of media, use of compound, amount of water and time. Type of media, time and speed were found to significantly influence waviness reduction and weight loss. Surface electron microscopy images demonstrated the additional effects of deburring and corner rounding. Results on previous studies with specimens made of metal showed similar results. Further investigation is required to optimize waviness reduction and polish parts in a second post-processing step.