Search Results (609)

The reconstruction of complex orbitomaxillary defects requires biomaterials that can simultaneously provide structural stability, biocompatibility, and accurate restoration of facial volume and contour. While rigid polymers such as polyetheretherketone (PEEK) offer reliable mechanical support, they do not adequately replicate the viscoelastic behavior of soft tissues. This report presents a translational revision case employing a personalized hybrid biomaterial approach that combines a 3D-printed PEEK implant for structural orbital floor support with a patient-specific polydimethylsiloxane (PDMS) implant for malar volumetric augmentation. Reconstruction was planned using CT segmentation and contralateral mirroring. Patient-specific implants were subsequently designed using CAD/CAM techniques, combining a rigid PEEK implant for structural orbital support with a flexible PDMS implant for malar volumetric augmentation with complementary mechanical properties. Revision surgery included the removal of inadequately positioned titanium hardware, the release of incarcerated extraocular muscles, and the restoration of orbital anatomy and facial symmetry. Postoperative imaging demonstrated stable implant positioning and sustained orbitomaxillary stability. Despite successful anatomical reconstruction, residual functional sequelae, including strabismus related to the severity of the initial orbital trauma, persisted and were addressed separately in a staged manner, resulting in satisfactory ocular alignment and resolution of diplopia in primary gaze. This case underscores the complementary functional roles of rigid and elastic polymers and highlights the translational potential of PDMS as a permanent, patient-specific implant material for volumetric and contour restoration in craniofacial reconstruction. Full article

Background: Accurate digital impressions are crucial for the long-term success of implant-supported prostheses, with scan bodies playing a pivotal role in transferring the implant position into the virtual model. Recent work has focused on PEEK (polyether-etherketone) scan bodies because their optical behavior may facilitate intraoral scanning; however, the breadth and quality of supporting evidence remain unclear. Methods: This scoping review followed PRISMA-ScR reporting guidelines and was registered in the Open Science Framework (OSF; Registration DOI 10.17605/OSF.IO/CU3V8). Pub-Med/MEDLINE, Embase, and Scopus were searched through September 2025. Eligible designs included in vitro studies, randomized trials, observational studies, and technical reports evaluating PEEK scan bodies in implant dentistry. Screening and data extraction were performed in duplicate, and findings were synthesized descriptively. Results: The search identified 227 records, and after screening, 31 studies met the inclusion criteria. Most studies were in vitro, with limited clinical evidence, and only one prospective clinical study was identified. Outcomes commonly addressed trueness, precision, scan time, and handling. Comparators varied (e.g., titanium, resin; splinted vs. unsplinted), and the results on accuracy were heterogeneous, with deviations typically within clinically acceptable limits (<100 µm). Conclusions: PEEK scan bodies are applicable for digital implant impressions. Clinical data are sparse, though, and methods vary. Controlled clinical studies are necessary to confirm the accuracy, reliability, and indications of this approach compared to titanium ISBs. Full article

MXene, as a suitable and alternative 2D nanofiller incorporated into a proton exchange membrane (PEM), has recently received considerable attention because of desired mechanical stability, promising conductivity, and active surface functional groups. However, agglomeration or sedimentation in PEMs, as well as the water retention capacity under low humidity of MXene, are limiting factors in the field of PEMs. In this paper, modified MXene and TiO₂ nanoparticles used as functional nanofillers were incorporated into sulfonated poly (ether ether ketone) (SPEEK) to prepare novel SPEEK-based composite PEMs. The effects of the nanofiller contents on self-humidifying and protonic conductivity of the composite PEMs were also investigated under different temperatures. When the contents of functionalized MXene and modified TiO₂ are 5 wt.%, proton conductivity, water uptake and methanol permeability of the composite PEMs can be up to 0.143 S/cm, 60% and 2.27 × 10⁻⁷ cm²/s, respectively, which represent increases of about 192%, about 38% and a decrease of 47%, respectively, compared with that of primary SPEEK PEM. Under the synergistic action of functionalized MXene providing a higher number of exchangeable proton sites, modified TiO₂ with inherent hydrophilicity enhancing water retention and Pt providing catalytic sites for the H₂/O₂ reaction to generate water in situ, the self-humidifying capability and proton conductivity of the composite PEMs were improved significantly. Full article

Solvent-free, continuous manufacture of carbon-fiber/poly(ether ether ketone) (CF/PEEK) towpregs via fluidized-bed powder coating requires stable powder fluidization together with controllable coating residence time. A laboratory-scale continuous coating line comprising a creel, guiding/tension rollers, a vibrated fluidized-bed coater, as well as a take-up unit was designed and commissioned. Subsequently, a two-stage optimization and modeling framework was developed. First, PEEK powder fluidization was optimized using a Taguchi L9 design, varying air pressure ($P$), powder weight ($W$), and vibration frequency ($f$); bed expansion ratio ($\epsilon$) and average surface bubble diameter ${(D}_b)$ were measured and ANOVA identified air pressure as the primary contributor to $\epsilon$ (83.4%), establishing a stable operating window. Second, within this window, coating performance was assessed by varying line speed ($V_{line}$) and coating-roller position ($H_r$) in 12 runs and combining them into a geometry-based residence time ($R_t$) for simplified control. Coating quality was quantified based on fiber volume fraction ($Vf$) and composite tensile strength (${\mathsf{\sigma }}_c$) after consolidation. The best condition in the tested range was $Hr=0.5 \mathrm{c}\mathrm{m}$ and $V_{line}=1.5 \mathrm{m}/\mathrm{m}\mathrm{i}\mathrm{n}$ ($R_t=0.54 \mathrm{s}$), achieving 61.5% $Vf$ and 1800.5 MPa tensile strength. The resulting mathematical models predicted $Vf$ and ${\mathsf{\sigma }}_c$ with good accuracy ($R^2\ge 0.92$), supporting parameter selection and process optimization for continuous CF/PEEK towpreg production. Full article

This study develops a kinetic model that captures poly-ether-ether-ketone (PEEK) crystallization over a temperature $T$ window from glass transition ($T_g$) to melting ($T_m$) temperature, and across cooling rates from 5 to ~10³ °C/min. The framework is a parallel dual-Nakamura formulation whose isokinetic parameters {$k_i\left(T\right),n_i,w_i\left(T\right)$} are obtained from a bi-level non-linear regression of isothermal crystallization tests conducted using a flash-differential scanning calorimeter (FSC). The weight $w_i\left(T\right)$ partitions the faster primary and slower secondary crystallization and is represented by a physics-based analytical function that captures its dome-shaped temperature dependence. A maximum isothermally achievable enthalpy function is introduced so that the model predicts enthalpy $\Delta H\left(t\right)$ natively under arbitrary thermal profiles. To extend this isothermal backbone to non-isothermal conditions, two explicit cooling-rate-dependent scalars are introduced, $\omega \left(\dot{T}\right)$ and $\chi \left(\dot{T}\right)$, which shift $w_i\left(T\right)$ and limit attainable crystallinity at high cooling rates respectively. Finally, a rate-dependent induction time relation is added to adjust the onset of crystallization. Calibrating these rate functions against non-isothermal experiments, while keeping the isokinetic parameters fixed, yields a single isothermal–non-isothermal model that predicts $\Delta H\left(t\right)$ under arbitrary $T\left(t\right)$ profiles. Model performance is validated using an interrupted FSC experiment with a multi-segment cooling program that mimics a local transient thermal history of PEEK during additive manufacturing. The sample is cooled through successive constant-rate segments with intermittent quench–remelt cycles to probe the accumulated crystallinity along the path. Without additional fitting, the model predicts the measured enthalpy evolution with R² ≈ 0.95. The framework thus provides a practical route for predicting polymer crystallinity under processing-relevant thermal histories. Full article

Self-curing poly(methyl methacrylate) (PMMA) remains widely used for provisional restorations and denture bases; however, its limited mechanical strength and susceptibility to water-related degradation restrict long-term performance. This study investigated the concentration-dependent reinforcement of self-curing PMMA with polyetheretherketone (PEEK) particles and evaluated mechanical properties and physicochemical stability. PMMA specimens containing different PEEK concentrations were fabricated and tested for flexural strength, compressive strength, surface hardness, water sorption, and water solubility according to standardized protocols. Mechanical performance demonstrated a concentration-dependent enhancement, with moderate PEEK incorporation significantly improving strength parameters compared to the control group. Excessive filler loading, however, did not yield proportional improvements. Water sorption and solubility values remained within clinically acceptable and ISO-recommended limits. These findings suggest that controlled PEEK reinforcement provides a feasible approach to enhancing the mechanical durability of self-curing PMMA without compromising physicochemical stability. The study offers a practical material modification strategy for improving interim prosthetic materials in clinical dentistry. Full article

CAD/CAM polymer-based dental materials are increasingly used as metal-free alternatives for fixed and implant-supported restorations. High-performance polymers such as polyetheretherketone (PEEK), fiber-reinforced composites, and graphene-reinforced polymers have been introduced to improve material stability; however, evidence regarding the effects of thermal aging on their physicochemical and biological properties remains limited. In this study, PEEK, a fiber-reinforced composite (FRC), and a graphene-reinforced PMMA-based polymer (G-CAM) were evaluated. Twenty-seven disc-shaped specimens (10 × 2 mm; n = 9 per material) were fabricated and subjected to 10,000 thermal cycles between 5 and 55 °C. Color change (ΔE₀₀), surface roughness (Ra), and Vickers microhardness (VHN) were measured before and after aging. Chemical stability was assessed using FTIR and Raman spectroscopy, surface morphology by SEM analysis, and biological safety by cytotoxicity testing. Material-dependent differences were observed in color stability, surface roughness, and microhardness after thermal aging (p < 0.05). Microhardness decreased in the fiber-reinforced and graphene-reinforced materials, whereas PEEK showed no significant change. Spectroscopic analyses indicated preserved chemical structure, and all materials demonstrated acceptable cytocompatibility. Thermal aging influenced material behavior while chemical stability and biological safety were maintained, highlighting the importance of considering aging behavior during material selection for prosthetic restorations. Full article

Carbon-Fiber-Reinforced Polyetheretherketone (CFR-PEEK) instrumentation is increasingly preferred in spinal oncology for its physical properties, minimizing imaging artifacts and facilitating precise postoperative radiotherapy planning and tumor surveillance. However, a significant technical limitation exists: the current unavailability of dedicated CFR-PEEK pedicle screws for the cervical spine. The smallest available implants are designed for thoracic use (minimum diameter 4.5 mm, minimum length 25 mm), posing substantial risks of neurovascular injury when applied to smaller cervical pedicles. We present a technical note/feasibility report illustrated by a single case of robot-assisted placement of thoracic CFR-PEEK screws in the cervical spine for the treatment of a C7 Giant Cell Tumor. Following neoadjuvant therapy with Denosumab, a single-stage, two-step circumferential resection and reconstruction was performed. The anterior step was complicated by an iatrogenic injury to the highly adherent left vertebral artery (VA), which was successfully repaired. Consequently, the posterior step required maximal precision to preserve the sole remaining intact VA on the right side. Given the anatomical mismatch between the 4.5 mm thoracic screws and the narrow cervical pedicles (measuring as narrow as 3.2 mm on the critical right side), robotic navigation (ExcelsiusGPS^®) was utilized to plan and execute safe trajectories. Specifically, on the side of the intact VA, a small, controlled medial cortical violation was planned to avoid lateral vascular compromise. The procedure resulted in rigid, artifact-free stabilization with no immediate neurological sequelae. This single-case experience suggests that robotic guidance may facilitate adaptation of thoracic CFR-PEEK instrumentation to the cervical spine in selected oncologic scenarios; reproducibility, costs, and long-term outcomes remain uncertain. Full article

Orbital reconstruction following trauma remains challenging due to complex three-dimensional (3D) anatomy and limited surgical access. While pre-fabricated titanium mesh is standard, it requires extensive intraoperative manipulation and produces imaging artifacts. The 3D-printed polyetheretherketone (PEEK) patient-specific implants (PSIs) offer potential advantages; however, limited data exists for the acceptance of PEEK PSIs by surgeons compared to other established techniques. Fourteen surgeons performed simulated orbital reconstructions on nine cadaveric heads comparing titanium mesh and the 3D-printed PEEK PSIs. Titanium mesh was used for Class II orbital floor fractures, while the 3D-printed PEEK PSIs (native and radiopaque formulations) were used for Class IV defects. Surgeons were blinded to the PEEK formulation type. Outcomes included operative efficiency, handling characteristics, fit quality, and mechanical stability using validated 5-point Likert scales and objective timing. The 3D-printed PEEK PSIs demonstrated faster procedure times (9.5 ± 5.3 vs. 11.2 ± 5.1 min) and superior fit quality (2.00 ± 1.04 vs. 2.18 ± 0.60) and mechanical stability (1.67 ± 0.49 vs. 1.91 ± 0.54), with 100% rated stable versus 91% for the titanium mesh. Surgeons could not distinguish between the native and radiopaque PEEK formulations. Most surgeons (64.3%) preferred situation-dependent material selection. The 3D-printed PEEK PSIs demonstrated advantages in handling, fit quality, and mechanical stability for complex defects, while the titanium mesh showed a lower learning curve for simple reconstructions. Radiopaque enhancement expands PEEK’s clinical utility without compromising handling. Full article

Carbon Fiber Reinforced Thermoplastic Polymer (CFRTP) composites, particularly those utilizing Polyetheretherketone (PEEK) matrices, are becoming more demanding in the automotive and aerospace industries because of their outstanding strength, resilience to impact, and capacity for recycling. The employed heating methodology to prepare these materials is important both to improve them through uniform temperature distribution and to manage the energy consumption. The current study aims to address the encountered issues by experimentally comparing the radiative–thermal performance of medium-wave (1.4–2.5 µm) Quartz Tungsten (QTM) and long-wave (3.5–5.5 µm) Ceramic (FFEH) infrared emitters using a modular laboratory-scale heating system. While QTM emitters provided rapid heating rates, they induce significant through-thickness thermal gradients and surface degradation risks due to spectral mismatch with the polymer. In contrast, long-wave Ceramic emitters demonstrate superior spectral compatibility with PEEK, expanding the safe processing window and achieving complete melting at 343 °C with high thermal uniformity and approximately 18% lower effective energy demand compared to QTM systems. Furthermore, the structural integrity of the consolidated laminates has been validated through tensile testing, yielding an average tensile strength of 873 MPa and a tensile modulus of 56.3 GPa. These findings confirm the importance of optimizing the emitter wavelength not only for energy efficiency, but also for ensuring matrix integrity and mechanical performance in high-performance composite manufacturing. Full article

PEEK (polyetheretherketone) is a semi-crystalline thermoplastic polymer which, thanks to its excellent mechanical properties, chemical resistance, and high biocompatibility, is widely used in medicine, especially in biomedical engineering. The dynamic development of additive technologies, especially FFF (Fused Filament Fabrication), has enabled the production of personalized medical implants from PEEK, such as skull implants, dental implant components, and orthopedic implants like spine, knee and hip implants. Therefore, the aim of the study was to evaluate the polymer as an alternative material for orthopedic applications and to analyze the effect of annealing and soaking in PBS solution on its strength properties. Heat treatment improves the strength properties of the material. On the other hand, prolonged soaking in PBS solution, which simulates physiological conditions, can lead to changes in the interlayer bonds of the filament layers, which in turn affects the strength properties of the material. Full article

To improve the quality of additive manufacturing of PEEK parts, copolymers with varying 4,4′-dichlorodiphenylsulfone (DCDPS) contents were synthesized. A study of the thermophysical properties of the resulting copolymers revealed that increasing the DCDPS content leads to lower melting temperatures, crystallization temperatures, and degree of crystallinity, while simultaneously increasing the glass transition temperature. It was found that structural amorphization leads to a predictable decrease in the strength and elastic modulus of both cast and printed samples. However, at a DCDPS concentration of 15%, the decrease in mechanical properties is offset by an increase in polymer chain rigidity. The practical result of this study was the successful adaptation of the material to FDM printing: copolymers with DCDPS contents in the range of 5–20% ensured stable molding without deformation or delamination, demonstrating an optimal balance between processability and performance. Full article

Carbon fiber-reinforced polyetheretherketone (CF/PEEK) thermoplastic composites are increasingly applied in aerospace structures due to their outstanding mechanical and thermal properties. However, their strengthening mechanism and damage evolution under repeated low-velocity impacts remains inadequately explored. This study systematically investigates the mechanical response and failure mechanisms of CF/PEEK laminates subjected to sequential single and second impacts at energy levels of 10 J, 20 J, and 30 J. Through comprehensive analysis of impact parameters (peak load, energy absorption, residual displacement), optical microscopy and ultrasonic C-scan, this study reveals that the load-bearing increase under repeated low-velocity impacts results from the combined effects of multiple mechanisms, including matrix plastic deformation, local compaction, matrix damage, and interlaminar failure. Under initial impacts, laminates exhibit high load-bearing capacity and energy dissipation, which are dominated by plastic deformation and matrix failure at 10 J and 20 J, whereas the 30 J impact causes pronounced fiber failure. An anomalous increase in peak load is observed during secondary impacts, which is attributed to matrix compaction-induced strengthening resulting from the initial impact. Optical microscopy and C-scan quantification demonstrate that, while the initial impact induces compaction-related strengthening, it also causes internal damage, which leads to aggravated damage evolution during the subsequent impact. The findings provide fundamental insights into damage accumulation in thermoplastic composites and directly inform impact-resistant design strategies. Full article

This Finite Element Analysis (FEA) study examined the stability of Polyetheretherketone (PEEK) miniscrews and tissue response in the posterior maxilla under varying angulations. A Cone beam computed tomography (CBCT)-derived three-dimensional model of the fully dentate maxilla was generated, featuring anatomical structures (teeth, periodontal ligament (PDL), alveolar bone) and orthodontic components (brackets, transpalatal arch, archwires). PEEK miniscrews were positioned bilaterally in the regions of the second premolar-first molar and first molar-second molar. A force of 100 g was applied perpendicular to the archwire. Four insertion angulations (45°, 70°, 90°, and 110°) were simulated. FEA revealed a consistent posterior displacement pattern: crowns tipped distally and buccally, while roots moved mesially, with intrusion. The first molar’s PDL peaked at 110°. Cortical bone stress was greatest in molars (1.41 × 10⁵ Pa at 70–110°). Cancellous bone stress peaked under 70° loading in the second molar (1.25 × 10⁵ Pa). PEEK miniscrews exhibited minimal deformation and low interfacial stress, confirming stable anchorage across all angles. Posterior PEEK miniscrews demonstrated excellent stability across all insertion angles, with 70° providing optimal biomechanical efficiency for intrusion. The first molar’s PDL experienced the highest stress concentrations at extreme angles. These findings offer clinical guidance for miniscrew placement to achieve effective intrusion while maintaining tissue safety. Full article

This finite element study compared the effects of prosthetic superstructure material and supporting implant number on stresses in implants, multiunit abutments, and restorations, and on peri-implant bone strains under bruxism-like loading. Two posterior mandibular models representing missing left FDI 34–36 were generated: a 2-implant configuration (implants at 34 and 36) and a 3-implant configuration (implants at 34, 35, and 36), each restored with a three-unit implant-supported fixed bridge. For each configuration, three superstructure materials were simulated: cobalt–chromium (Co–Cr), polyetheretherketone (PEEK), and monolithic zirconia (MZ). Static parafunctional loads were applied as a 500 N oblique load (30° to the implant long axis; 125 N to each buccal cusp) and a 1000 N vertical load applied to the central fossae. Cortical bone generally exhibited higher strain than trabecular bone, and the maximum cortical principal strain under vertical loading averaged approximately 5800 μɛ. The highest implant von Mises stress occurred in the first molar implant of the 2-implant MZ model under oblique loading, while the maximum under vertical loading was 236 MPa (also 2-implant MZ). Prosthetic peak stresses reached 184 MPa under vertical loading (3-implant PEEK composite–veneered model) and 233 MPa under oblique loading (2-implant MZ), with a minimum of 51 MPa in the 3-implant PEEK framework under vertical loading. Overall, increasing implant number reduced the stress/strain values, and MZ showed comparatively higher stress and strain levels. Full article