Thickness-extensible higher order plate theory with enforced C1 continuity for the analysis of PEEK medical implants.

Plate-like structures had been thoroughly studied in literature over years to reduce the computational space from 3D to 2D. Many of these theories suffer either from satisfying the free traction condition or thickness extensibility in addition to the consistency of transverse shear strain energy. This work presents a higher order shear deformation thickness-extensible plate theory (eHSDT) for the analysis of plates. The proposed eHSDT satisfies the condition of free traction as other theories do but it also satisfies the condition of consistency of transverse shear strain energy which is neglected by many theories in the area of plates and shells. The implementation of the proposed theory in displacement-based finite element procedure requires continuity of derivatives across elements. This necessary condition was achieved using the penalty enforcement method for derivative-based nodal degrees of freedom across the standard 9-nodes Lagrange element. The theory was tested for elastic bending deformation of Polyether-ether-ketone (PEEK) which is one of the basic materials for medical implants. The theory showed good accuracy compared to experimental data of the three-points bending test. The present eHSDT was also tested for different conditions with a wide range of aspects ratios (thin to thick plates) and different boundary conditions. The accuracy of the proposed eHSDT was verified against exact solutions for these conditions which showed the advantage over other approaches and commercial finite element packages.

A Single-Center, Observational Study Assessing Functional Outcomes After Arthroscopic Anterior Cruciate Ligament Reconstruction Using Suspensory Tibial Fixation With a Polyether Ether Ketone (PEEK) Button.

Background Anterior cruciate ligament reconstruction (ACLR) is a crucial procedure in orthopedic surgery. This study evaluates the efficacy and safety of ACLR employing suspensory tibial fixation with a polyether ether ketone (PEEK) button. Methodology This retrospective observational study conducted at Sai Shree Hospital, Pune, India, between November 2023 and December 2023 enrolled 47 subjects aged 18-60 years who underwent arthroscopic ACLR utilizing the T-Button-A Adjustable Loop Ultra-High-Molecular-Weight Polyethylene Suture PEEK button. The functional outcomes and patient-reported outcomes were assessed using the International Knee Documentation Committee (IKDC) score, the Modified Cincinnati Rating System Questionnaire (MCRS), the Single Assessment Numeric Evaluation (SANE) score, the Tegner Activity Level (TAL) Scale, and Knee Injury and Osteoarthritis Outcome Score (KOOS) quality of life subscale. Results Femoral fixation utilized 27 (57.4%) Proloop Ultra Adjustable Loop Button 60 mm, 19 (40.4%) Infiloop Fixed Loop Button 20 mm, and 1 (2.1%) Infiloop Fixed Loop Button 30 mm. Tibial fixation solely relied on T-Button A (PEEK Tibial Button With Adjustable Loop 90 mm). Postoperative evaluations revealed favorable IKDC (79.49 ± 12.67), MCRS (81.32 ± 11.57), SANE (77.83 ± 11.11), TAL Scale (3.87 ± 0.99) and KOOS quality of life subscale (83.81 ± 13.07) scores. Conclusions The findings affirm the efficacy and safety of arthroscopic ACLR utilizing suspensory tibial fixation with the PEEK button, supporting its use for improved patient outcomes.

Surface modification of PEEK implants for craniofacial reconstruction and aesthetic augmentation-fiction or reality?

Facial implantology, a crucial facet of plastic and reconstructive surgery, focuses on optimizing implant materials for facial augmentation and reconstruction. This manuscript explores the use of Polyetheretherketone (PEEK) implants in craniofacial surgery, highlighting the challenges and advancements in this field. While PEEK offers mechanical resilience, durability, and compatibility with imaging modalities, its biologically inert nature hinders integration with the host tissue, which may lead to complications. In this systematic review, our aim was to assess the current state of knowledge regarding the clinical evaluation of Polyetheretherketone (PEEK) implants in facial implantology, with a focus on craniofacial augmentation and reconstruction in human studies. Additionally, we explore and discuss surface and structural modifications that may enhance bioreactivity and reduce complications in PEEK implants. A systematic review identified 32 articles detailing the use of PEEK Patient-Specific Implants (PSIs) in 194 patients for both reconstructive and aesthetic purposes. Complications, including infections and implant failures, were reported in 18% of cases, suggesting the need for improved implant materials. The discussion delves into the limitations of PEEK, prompting the exploration of surface and structural modifications to enhance its bioreactivity. Strategies, such as hydroxyapatite coating, titanium coating, and porous structures show promise in improving osseointegration and reducing complications. However, the literature review did not reveal reports of coated or modified PEEK in facial reconstructive or aesthetic surgery. In conclusion, although PEEK implants have been successfully used in craniofacial reconstruction, their biological inertness poses challenges. Surface modifications, particularly hydroxyapatite coatings, provide opportunities to promote osseointegration. Future research should focus on prospective long-term studies, especially in craniofacial surgery, to investigate the stability of uncoated PEEK implants and the potential benefits of surface modifications in clinical applications. Patient-specific PEEK implants hold promise for achieving durable craniofacial reconstruction and augmentation.

Comparison of the Retention and Fit of Polyether Ether Ketone Clasps during Fatigue Circulation Tests.

Purpose: The purpose of this study was to evaluate the fit and retention of clasps made of polyether ether ketone (PEEK) or cobalt-chromium alloy (Co-Cr) at different tooth positions in experimental simulations of in vitro wear and removal for 5 years. Methods: Standard crowns of the right mandibular first premolar (44) and first molar (46) were selected, and a circular three-arm clasp was designed, scanned and fabricated. Ten PEEK clasps were used as the experimental group, and 10 Co-Cr clasps were used as the control group. The seating channel was parallel to the side of the abutment base in both groups. The oral environment was simulated, and each clasp was tested in artificial saliva for 7200 cycles while the change in clasp retention force was recorded. The fit before and after the fatigue cycles was measured by the silicone rubber film copying method. Data were statistically analyzed using the independent samples t-test (α = 0.05). Results: Before circulation, the retention forces of the clasps at position 44 were 4.61 ± 0.91 N (PEEK) and 47.50 ± 10.59 N (Co-Cr), and the forces at position 46 were 3.38 ± 0.49 N (PEEK) and 28.79 ± 10.99 N (Co-Cr). After circulation, the retention forces of the clasps at position 44 were 4.15 ± 0.91 N (PEEK) and 13.90 ± 6.59 N (Co-Cr), and the forces at position 46 were 2.93 ± 0.25 N (PEEK) and 11.56 ± 3.93 N (Co-Cr). Before circulation, the fit of each clasp at the reference points (clasp tip, clasp arm, and occlusal rest) was between 41.70 µm and 170.29 µm, and after circulation, they were between 64.05 µm and 182.59 µm. The retention force and fit of the PEEK clasps did not undergo statistically significant changes from before to after circulation (P > 0.05). However, there were statistically significant (P < 0.05) decreases in the retention force of the Co-Cr clasps and the fit of the clasp tip during circulation. In addition, there was a sudden and large change in the retention force of the Co-Cr clasps after approximately 360 cycles. Conclusions: The retention force and suitability of the PEEK clasps met the requirements for clinical use during testing that simulated the in vitro wear and removal procedure for 5 years. Compared with the Co-Cr clasp, the PEEK clasp underwent less fatigue deformation, which makes it feasible for clinical applications.

Composite-veneering of polyether-ether-ketone (PEEK): evaluating the effects of different surface modification methods on surface roughness, wettability, and bond strength.

This study aimed to evaluate the effects of different surface modification methods on the surface roughness, contact angle, and bond strength of composite-veneer materials of polyether-ether-ketone (PEEK). Fifty-five specimens (n = 11) with a size of 7 × 7 × 2 mm were cut out from PEEK discs. The specimens were divided into five groups with different surface treatments: no treatment (NO) (control group), sulfuric acid (SA), plasma (P), femtosecond laser (FS), and Nd-YAG laser (NY). After the surface treatments, the specimens were checked for roughness, contact angle, and bond strength of the composite-veneer material. Data were analyzed with the Welch test for roughness, contact angle, and bond strength parameters. Individual Pearson correlation tests were executed for all surface treatment groups to determine any significant correlations among roughness, contact angle, and bond strength parameters (P < .001). Roughness, contact angle, and bond strength values were affected by surface modification methods (P < .001). In comparison to the control group, NY and FS treatments increased the surface roughness and bond strength; they also provided bond strength values comparable to the SA group. When the relationship between the variables was examined, no correlation was seen between roughness, contact angle, and bond strength values for the NY, SA, and control groups (P > .05); however, significant correlations were determined between the contact angle and surface roughness values for the P and FS groups (P < .05). Femtosecond and Nd-YAG laser treatments are viable surface modification alternatives to the sulfuric acid treatment for the PEEK material.

Retentive Forces and Deformation of Fitting Surface in RPD Clasp Made of Polyether-Ether-Ketone (PEEK).

BACKGROUND: Polyetheretherketone (PEEK) has provided the option to fabricate RPDs with aesthetics unlike metal RPDs, but little attention has been paid to its suitability, especially towards the retentive forces and deformation of the clasp. This study aimed to examine the retentive forces and the fitting surface (inner surface) deformation of clasps made from PEEK and compare it with cobalt-chromium (Co-Cr) clasp. METHODS: Forty-two circumferential clasps (14 Co-Cr and 28 PEEK) were fabricated and divided into two groups with clasp undercuts (0.25 mm and 0.5 mm) with thicknesses of 1 mm and 1.5 mm. Each was examined for retentive forces after cycle test on its abutment for 360 cycles. Initial and final retentive forces were recorded. The fitting surface deformation was determined using 3-Matic research analysis software. RESULTS: The results revealed that highest mean initial retentive force was of Co-Cr clasps with 0.50 mm undercut 22.26 N (±10.15 N), and the lowest was the 1 mm PEEK clasps with 0.25 mm undercut 3.35 N (±0.72 N) and highest mean final retentive force was the Co-Cr clasps with 0.50 mm undercut 21.40 N (±9.66 N), and the lowest was the 1 mm PEEK clasps with 0.25 mm undercut 2.71 N (±0.47 N). PEEK clasps had a lower retentive force than Co-Cr clasps with 0.50 undercut. PEEK clasps (1.5 mm) at 0.25 mm undercut had the least deformation (35.3 µm). PEEK showed significantly less deformation (p ≤ 0.014) than Co-Cr. CONCLUSION: The deformation of PEEK clasps fitting surface was lower than Co-Cr clasps and retentive forces were close to the Co-Cr clasps, suggesting the use of PEEK as an aesthetic clasp option for RPD framework.

Engineering Multifunctional Polyether Ether Ketone Implant: Mechanics-Adaptability, Biominerialization, Immunoregulation, Anti-Infection, Osteointegration, and Osteogenesis.

Polyether ether ketone (PEEK) has become one of the most promising polymer implants in bone orthopedics, due to the biocompatibility, good processability, and radiation resistance. However, the poor mechanics-adaptability/osteointegration/osteogenesis/antiinfection limits the long-term in vivo applications of PEEK implants. Herein, a multifunctional PEEK implant (PEEK-PDA-BGNs) is constructed through in situ surface deposition of polydopamine-bioactive glass nanoparticles (PDA-BGNs). PEEK-PDA-BGNs exhibit good performance on osteointegration and osteogenesis in vitro and in vivo, due to their multifunctional properties including mechanics-adaptability, biominerialization, immunoregulation, anti-infection, and osteoinductive activity. PEEK-PDA-BGNs can show the bone tissue-adaptable mechanic surface and induce the rapid biomineralization (apatite formation) under a simulated body solution. Additionally, PEEK-PDA-BGNs can induce the M2 phenotype polarization of macrophages, reduce the expression of inflammatory factors, promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and improve the osseointegration and osteogenesis ability of the PEEK implant. PEEK-PDA-BGNs also show good photothermal antibacterial activity and can kill 99% of Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA), suggesting their potential antiinfection ability. This work suggests that PDA-BGNs coating is probably a facile strategy to construct multifunctional (biomineralization, antibacterial, immunoregulation) implants for bone tissue replacement.

Comparison between the use of polyether ether ketone and stainless steel columns for ultrasonic-assisted extraction under various ultrasonic conditions.

The ultrasound-assisted extraction (UAE) was conducted using the stainless steel (SS) and polyether ether ketone (PEEK) columns and analyzed with high-performance liquid chromatography (HPLC) to understand the mechanism of ultrasound-assisted chromatography (UAC). Empty SS and PEEK columns were used to extract dyes from a fabric under identical conditions with several parameters including the initial ultrasonic bath temperatures (30 °C and 40 °C), ultrasound power intensities (0, 20, 40, 60, 80, and 100 %), ultrasound operation modes (normal and sweep), and ultrasound frequencies (25 kHz, 40 kHz, and 132 kHz) to compare their extraction capabilities. After 30 min of extraction, the amount of extract was determined by HPLC. The PEEK material was significantly affected by ultrasonic radiation compared to the SS material, especially at a higher temperature (40 °C), power intensity (100 %), and frequency (132 kHz) with sweep mode. At a maximum power density of 45 W/L, the extraction effectiveness ratio of PEEK to SS was in the range of 1.8 - 3.9 depending on the specific frequency, initial temperature, and with or without temperature control. The most optimal ultrasound frequencies, in terms of enhancing extraction effectiveness, are in the order of 132 kHz, 40 kHz, and 25 kHz. Unlike the SS material, the PEEK material was more affected by temperature and acoustic effects under identical conditions, especially at 132 kHz ultrasound frequency. In contrast, at lower frequencies of 40 kHz and 25 kHz, no significant differences in the acoustic effects were observed between the PEEK and SS materials. The findings of this study contribute to elucidating the roles of column materials in UAE and UAC.

The Shape Memory Properties and Actuation Performances of 4D Printing Poly (Ether-Ether-Ketone).

Shape-memory polymers (SMPs) have gradually emerged in the mechanism and biomedical fields and facilitate the upgrading of industrial mechanisms and the breakthrough of technical bottlenecks. However, most of the SMPs are infeasible in harsh environments, such as aerospace, due to the low glass transition temperature. There are still some works that remain in creating truly portable or non-contacting actuators that can match the performances and functions of traditional metal structures. Polyether-ether-ketone (PEEK) with a high glass transition temperature of 143 °C is endowed with outstanding high-temperature resistance and radiation-resistant properties and shape memory behavior. Thus, we explore the shape-memory properties and actuation performances of high-temperature PEEK in bending behaviors. The shape-recovery ratio, actuation speed and force under different programming conditions and structure parameters are summarized to complete the actuation capacities. Meanwhile, a metallic ball transported by shape-memory PEEK and deployed drag sail with thermo-responsive composite joints were shown to verify the potential in aerospace.

Surface Modification of Poly(ether ether ketone) by Simple Chemical Grafting of Strontium Chondroitin Sulfate to Improve its Anti-Inflammation, Angiogenesis, Osteogenic Properties.

Besides inducing osteogenic differentiation, the surface modification of poly(ether ether ketone) (PEEK) is highly expected to improve its angiogenic activity and reduce the inflammatory response in the surrounding tissue. Herein, strontium chondroitin sulfate is first attempted to be introduced into the surface of sulfonated PEEK (SPEEK-CS@Sr) based on the Schiff base reaction between PEEK and ethylenediamine (EDA) and the amidation reaction between EDA and chondroitin sulfate (CS). The surface characteristics of SPEEK-CS@Sr implant are systematically investigated, and its biological properties in vitro and in vivo are also evaluated. The results show that the surface of SPEEK-CS@Sr implant exhibits a 3D microporous structure and good hydrophilicity, and can steadily release Sr ions. Importantly, the SPEEK-CS@Sr not only displays excellent biocompatibility, but also can remarkably promote cell adhesion and spread, improve osteogenic activity and angiogenic activity, and reduce the inflammatory response compared to the original PEEK. Therefore, this study presents the surface modification of PEEK material by simple chemical grafting of strontium chondroitin sulfate to improve its angiogenesis, anti-inflammation, and osteogenic properties, and the as-fabricated SPEEK-CS@Sr has the potential to serve as a promising orthopedic implant in bone tissue engineering.

Hole Morphology and Keyhole Evolution during Single Pulse Laser Drilling on Polyether-Ether-Ketone (PEEK).

Polyether-ether-ketone (PEEK), with its superior mechanical, chemical, and thermal properties, as well as high biocompatibility, has been used in aerospace, electronics, and biomedical applications. In this paper, a large number of experiments of single-pulse laser drilling on PEEK were performed to analyze the hole morphology and keyhole evolution, which were characterized by an optical microscope, charge-coupled device (CCD), and high-speed camera. A novel method is proposed to observe and measure the dimension of the processed hole rapidly right after laser drilling for special polymer materials with wear-resistance and non-conductivity. Morphological characteristics of holes are presented to illustrate the effect of pulse width and peak power on hole depth, hole diameter, and aspect-ratio. The obtained maximum drilling depth was 7.06 mm, and the maximum aspect-ratio was 23. In situ observations of the dynamic process of laser drilling, including the keyhole evolution together with ejection and vaporization behavior, were also carried out. The keyhole evolution process can be divided into three stages: rapid increment stage (0−2 ms) at a rate of 2.1 m/s, slow increment stage (2−4 ms) at a rate of 0.3 m/s, and stable stage (>4 ms). Moreover, the variation of dimensionless laser power density with the increase in pulse width was calculated. The calculated maximum drilling depth based on energy balance was compared with the experimental depth. It is proven that the laser−PEEK interaction is mainly influenced by a photothermal effect. Ejection is the dominant material-removal mechanism and contributes to over 60% of the depth increment during the rapid increment stage, while vaporization is dominant and contributes to about 80% of the depth increment during the slow increment stage. The results reveal the material removal mechanism for single-pulse laser drilling on PEEK, which is helpful to understand the dynamic process of keyhole evolution. This not only provides a processing window for future laser drilling of PEEK but also gives a guide for the manufacturing of other polymers.

Modification of polyether ether ketone for the repairing of bone defects.

Bone damage as a consequence of disease or trauma is a common global occurrence. For bone damage treatment-bone implant materials are necessary across three classifications of surgical intervention (i.e. fixation, repair, and replacement). Many types of bone implant materials have been developed to meet the requirements of bone repair. Among them, polyether ether ketone (PEEK) has been considered as one of the next generation of bone implant materials, owing to its advantages related to good biocompatibility, chemical stability, x-ray permeability, elastic modulus comparable to natural bone, as well as the ease of processing and modification. However, as PEEK is a naturally bioinert material, some modification is needed to improve its integration with adjacent bones after implantation. Therefore, it has become a very hot topic of biomaterials research and various strategies for the modification of PEEK including blending, 3D printing, coating, chemical modification and the introduction of bioactive and/or antibacterial substances have been proposed. In this systematic review, the recent advances in modification of PEEK and its application prospect as bone implants are summarized, and the remaining challenges are also discussed.

Mesh Ti6Al4V Material Manufactured by Selective Laser Melting (SLM) as a Promising Intervertebral Fusion Cage.

Intervertebral cages made of Ti6Al4V alloy show excellent osteoconductivity, but also higher stiffness, compared to commonly used polyether-ether-ketone (PEEK) materials, that may lead to a stress-shielding effect and implant subsidence. In this study, a metallic intervertebral fusion cage, with improved mechanical behavior, was manufactured by the introduction of a three-dimensional (3D) mesh structure to Ti6Al4V material, using an additive manufacturing method. Then, the mechanical and biological properties of the following were compared: (1) PEEK, with a solid structure, (2) 3D-printed Ti6Al4V, with a solid structure, and (3) 3D-printed Ti6Al4V, with a mesh structure. A load-induced subsidence test demonstrated that the 3D-printed mesh Ti6Al4V cage had significantly lower tendency (by 15%) to subside compared to the PEEK implant. Biological assessment of the samples proved that all tested materials were biocompatible. However, both titanium samples (solid and mesh) were characterized by significantly higher bioactivity, osteoconductivity, and mineralization ability, compared to PEEK. Moreover, osteoblasts revealed stronger adhesion to the surface of the Ti6Al4V samples compared to PEEK material. Thus, it was clearly shown that the 3D-printed mesh Ti6Al4V cage possesses all the features for optimal spinal implant, since it carries low risk of implant subsidence and provides good osseointegration at the bone-implant interface.

Safety assessment of the substance chopped carbon fibres, from carbonised polyacrylonitrile, for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of chopped carbon fibres, from carbonised polyacrylonitrile, as food contact material (FCM) substance No 1086, which is intended to be used as a filler for polyether ether ketone (PEEK) polymer at up to 40% w/w. The plastic is intended for repeated use in contact with all types of foods under all conditions of use. The chopped carbon fibres have a length of ■■■■■ and a diameter of ■■■■■, with no fragments lower than ■■■■■ in any dimension. They do not include a fraction of particles at the nanoscale and are fully embedded in the PEEK matrix, and therefore the fibres and any fragments are not expected to migrate. Based on the results of a battery of three genotoxicity tests, the Panel concluded that the substance does not raise a concern for genotoxicity. Therefore, the CEP Panel concluded that the substance chopped carbon fibres, from carbonised polyacrylonitrile, with a minimum carbon content of 95% (at sizes not at the nanoscale) does not raise a safety concern for the consumer if the substance is used as a filler at up to 40% w/w for PEEK plastic in contact with all food types and under all conditions of use.

Additively-manufactured PEEK/HA porous scaffolds with highly-controllable mechanical properties and excellent biocompatibility.

Polyetheretherketone (PEEK) was widely applied into fabricating of orthopaedic implants, benefitting its excellent biocompatibility and similar mechanical properties to native bones. However, the inertness of PEEK hinders its integration with the surrounding bone tissue. Here PEEK scaffolds with a series of hydroxyapatite (HA) contents in gradient were manufactured via fused filament fabrication (FFF) 3D printing techniques. The influence of the pore size, HA content and printing direction on the mechanical properties of the PEEK/HA scaffolds was systematically evaluated. By adjusting the pore size and HA contents, the elastic modulus of the PEEK/HA scaffolds can be widely tuned in the range of 624.7-50.6 MPa, similar to the variation range of natural cancellous bone. Meanwhile, the scaffolds exhibited higher Young's modulus and lower compressive strength along Z printing direction. The mapping relationship among geometric parameters, HA content, printing direction and mechanical properties was established, which gave more accurate predictions and controllability of the modulus and strength of scaffolds. The PEEK/HA scaffolds with the micro-structured surface could promote cell attachment and mineralization in vitro. Therefore, the FFF-printed PEEK/HA composites scaffolds can be a good candidate for bone grafting and tissue engineering.

Research on the Fused Deposition Modeling of Polyether Ether Ketone.

As a special engineering polymer, polyether ether ketone (PEEK) has been used widely due to its excellent mechanical properties, high thermal stability, and chemical resistance. Fused deposition modeling (FDM) is a promising process for fabricating PEEK parts. However, due to the semi-crystalline property and high melting point of PEEK, determining appropriate process parameters is important to reduce warpage deformation and improve the mechanical properties of PEEK. In this article, the influence of raster angle and infill density was determined by single factor experiment, which are the two most important parameters. The results showed that samples with 0°/90° raster angle and 50% infill density had the best comprehensive properties in terms of warpage deformation, tensile strength, and specific strength. Subsequently, based on the results above, the effects of printing speed, nozzle temperature, platform temperature, raster width, and layer thickness were analyzed by orthogonal experiment. The results indicated that platform temperature had the greatest impact on warpage deformation while printing speed and nozzle temperature were significant parameters on tensile strength. Through optimization, warpage deformation of the samples could be reduced to almost 0 and tensile strength could increase by 19.6% (from 40.56 to 48.50 MPa). This will support the development of FDM for PEEK.

Effects of printing path and material components on mechanical properties of 3D-printed polyether-ether-ketone/hydroxyapatite composites.

Polyether-ether-ketone (PEEK) exhibits excellent mechanical properties and biocompatibility. Three-dimensional (3D) printing of PEEK bone substitutes has been widely used in clinical application. However, the inertness of pure PEEK hinders its integration with the surrounding bone tissue. In this study, for the first time, PEEK/hydroxyapatite (HA) composite specimens were fabricated using fused filament fabrication (FFF) technology. PEEK/HA filaments with HA contents of 0-30 wt% were fabricated via mechanical mixing and extrusion. The HA distributions inside the composite matrix and the surface morphology characteristics of the PEEK/HA composites were examined. The effects of the printing path and HA content on the mechanics of the PEEK/HA composites were systematically investigated. The results indicated that the HA particles were uniformly distributed on the composite matrix. With an increase in the HA content, the modulus of the PEEK/HA composite increased, while the strength and failure strain concomitantly decreased. When the HA content increased to 30 wt%, the tensile modulus of the composite increased by 68.6% compared with that of pure PEEK printed along the horizontal 90° path, while the tensile strength decreased by 48.2% compared with that of pure PEEK printed along the vertical 90° path. The fracture elongation of the printed specimens with different HA contents decreased in the following order: horizontal 0° > horizontal 90° > vertical 90°. The best comprehensive mechanical properties were achieved for pure PEEK fabricated along the horizontal 0° path. The results indicate that FFF technology is applicable for additive manufacturing of PEEK/HA composites with controllable compositions. Printed PEEK/HA composites have potential for applications in the design and manufacturing of personalized bone substitutes.

3D-printed PEEK implant for mandibular defects repair - a new method.

Functional reconstruction of large-size mandibular continuity defect is still a major challenge in the oral and maxillofacial surgery due to the unsatisfactory repair effects and various complications. This study aimed to develop a new functional repair method for mandibular defects combined with 3D-printed polyetheretherketone (PEEK) implant and the free vascularized fibula graft, and evaluated the service performance of the implant under whole masticatory motion. The design criteria and workflows of the mandibular reconstruction were established based on the requirements of safety, functionality, and shape consistency. Both the biomechanical behavior and the mechanobiological property of mandibular reconstruction under various masticatory motion were investigated by the finite element analysis. The maximum von Mises stress of each component was lower than the yield strength of the corresponding material and the safety factor was more than 2.3 times, which indicated the security of the repair method can be guaranteed. Moreover, the actual deformation of the reconstruction model was lower than that of the normal mandible under most clenching tasks, which assured the primary stability. More than 80% of the volume elements in the bone graft can obtain effective mechanical stimulation, which benefited to reduce the risks of bone resorption. Finally, the novel repair method was applied in clinic and good clinical performances have been achieved. Compared with the conventional fibular bone graft for surgical mandibular reconstruction, this study provides excellent safety and stability to accomplish the functional reconstruction and aesthetic restoration of the mandible defect.

A non-inferiority comparison of Delta Medical's PEEK Suture Anchor and Smith & Nephew's PEEK Suture Anchor in arthroscopic rotator cuff repair: a multicenter prospective single-blind randomized controlled clinical trial.

BACKGROUND: To compare the early clinical outcomes and Magnetic Resonance Imaging (MRI) results of Delta Medical's PEEK (polyether ether ketone) suture anchor with those of Smith & Nephew's PEEK suture anchor in patients with arthroscopic rotator cuff repair. METHODS: A total of 106 patients in four different medical centers were randomly allocated into two groups: Delta Medical's PEEK suture anchor (53 patients); Smith & Nephew's PEEK suture anchor (53 patients). The MRI results and early clinical outcomes were evaluated at 3 and 6 months postoperatively. The University of California at Los Angeles (UCLA) shoulder rating scale and the visual analog scale (VAS) score for pain and range of motion were evaluated. MRI were performed at 3 and 6 months postoperatively to examine the integrity of the repaired rotator cuff tendon based on the Sugaya classification. RESULTS: Significant improvements in pain relief, shoulder function, and functional scores were observed in both groups after surgery regardless of the suture anchor applied (P<0.001). No differences observed in the functional scores and range of motion. The assessments of UCLA scores at 3 and 6 months produced no statistical differences (P=0.885 and 0.340, respectively). The mean VAS scores in group 1 did not reveal statistical differences at 3 and 6 months after surgery compared to group 2. No significant differences in the range of motion were found at each follow-up time-point and no shifting or breakage of the anchors occurred between the two groups (P>0.01). No major intra- or post-operative complications, such as infection, and vessel or nerve injury. CONCLUSIONS: Pain relief and shoulder function were improved after complete rotator cuff repair in both groups, regardless of the suture anchor applied. The difference in functional scores and range of motion were not significant in groups 1 and 2. Delta Medical's PEEK suture anchor had a non-inferiority effect compared to Smith & Nephew's PEEK suture anchor. Delta Medical's PEEK suture anchor was suitable for arthroscopic rotator cuff repair. TRIAL REGISTRATION: Chinese Clinical Trial Registry, identifier: ChiCTR2100051716.

The Surface Characteristics, Microstructure and Mechanical Properties of PEEK Printed by Fused Deposition Modeling with Different Raster Angles.

Additive manufacturing provides a novel and robust way to prepare medical product with anatomic matched geometry and tailored mechanical performance. In this study, the surface characteristics, microstructure, and mechanical properties of fused deposition modeling (FDM) prepared polyether-ether-ketone (PEEK) were systematically studied. During the FDM process, the crystal unit cell and thermal attribute of PEEK material remained unchanged, whereas the surface layer generally became more hydrophilic with an obvious reduction in surface hardness. Raster angle has a significant effect on the mechanical strength but not on the failure mechanism. In practice, FDM fabricated PEEK acted more like a laminate rather than a unified structure. Its main failure mechanism was correlated to the internal voids. The results show that horizontal infill orientation with 30° raster angle is promising for a better comprehensive mechanical performance, and the corresponding tensile, flexural, and shear strengths are (76.5 ± 1.4) MPa, (149.7 ± 3.0) MPa, and (55.5 ± 1.8) MPa, respectively. The findings of this study provide guidelines for FDM-PEEK to enable its realization in applications such as orthopedic implants.