PEEK Materials Research Articles

Fabrication of 3D printed Si3N4 bioceramics with superior comprehensive performance through ZnO nanowires doping

Silicon nitride (Si3N4) material holds significant potential as a widespread applied biomedical material with high reliability in mechanical properties and biological activity. This study utilized 3D printing techniques to fabricate Si3N4 bioceramics reinforced with zinc oxide (ZnO) nanowires, which overcomes the dilemma faced by traditional Si3N4 materials, which possess excellent mechanical properties but lack sufficient antibacterial performance, or porous Si3N4 materials that exhibit good antibacterial properties yet suffer from poor mechanical characteristics. Compared to Ti-alloy, Al2O3, PEEK, and conventional Si3N4 materials, the Si3N4 bioceramic with an addition of 5 wt percent (wt%) ZnO nanowires retains superior mechanical properties: bending strength of 735 MPa, fracture toughness of 8.25 MPa m1/2, vickers hardness of 14.8 GPa, and compressive strength of 2575 MPa. Furthermore, the material demonstrates commendable biocompatibility and outstanding antibacterial effects. Cellular activity on the surface of this material is also noted to be exceptionally vigorous. Research indicates that the synergistic effects of 3D printing characteristics and the appropriate inclusion of ZnO nanowires, which positively interact with β-Si3N4 crystals, are primarily responsible for the exceptional comprehensive performance of 3D printed Si3N4 bioceramics.

The Effect of Surface Properties of Different Types of Post Materials on Fracture Type

Introduction and Aim Considering the advantages and disadvantages of different clinical situations, the surface characteristics of the post materials significantly affect the connection of the post material with dentin. In this study, the surface properties of PEEK posts, which are not yet widely used as post materials, were examined in terms of their effects on dentin bonding. Method 66 extracted upper central incisor-type human teeth that had undergone canal treatment with single and straight root canals were used. Posts were produced ) (n=11) from metal, fiber, and PEEK materials to form six groups (CP-0, CP-1, FP-0, FP-1, PP-0, and PP-1). The surface roughness of each post was examined by using a tactile profilometer. Zirconium full crowns, compatible with the central maxillary incisor anatomy, were produced for 66 samples with completed post-core production and polymerized using dual-cure resin cement (Monobond plus Vivadent). Subsequently, the samples were subjected to fracture strength testing at a 135-degree angle to the long axis of the tooth from the palatal side of the zirconium crown at a speed of 0.02 cm/min using a universal testing machine. After the test, the samples were classified into three groups based on the type of fracture: adhesive, cohesive, and mixed. One-way ANOVA and Pearson’s chi-squared tests were used for statistical analysis. Results The surface roughness value of the PEEK post group (1.42 ± 0.21) was significantly lower than that of the metal and fiber post groups. Although no significant difference was found in terms of the fracture type, the adhesive failure rate was higher in the PEEK post group (P

Functionalized microporous sulfonated polyetheretherketone: Osteogenesis and anti-osteoclastogenesis effects via ROS and NLRP3-mediated pyroptosis in macrophages

The treatment of osteoporotic implant failures tends to be challenging due to an imbalance in bone homeostasis. Recently, the accumulation of intracellular reactive oxygen species (ROS) and activation of the inflammasome containing nucleotide-binding oligomerization domain-like-receptor family pyrin domain-containing 3 (NLRP3) protein have been shown to indirectly affect osteogenesis and osteoclastogenesis. Owing to the release of multi-metal ions from laponite (LAP), we fabricated a multifunctional LAP coating on a three-dimensional microporous sulfonated polyetheretherketone (SPEEK) surface via polydopamine (PDA) modification (SPEEK@PDA-LAP). The balance between osteogenesis and osteoclastogenesis was examined using macrophages in an osteo-immune microenvironment. Employing in vitro assays, we showed that the SPEEK@PDA-LAP alleviated intracellular ROS accumulation and inhibited the activation of NLRP3 inflammasome-mediated pyroptosis in macrophages, creating an osteoimmunomodulatory microenvironment to stimulate osteogenesis and inhibit osteoclastogenesis. The micro-computed tomography and histological results of in vivo experiments indicated that SPEEK@PDA-LAP implants reversed the balance between osteogenesis and osteoclastogenesis to promote the formation of new bone around the implant even under osteoporotic conditions. The results indicate that inhibiting the NLRP3 inflammasome and regulating intracellular ROS in macrophages can be an effective therapy for osteoporosis. These results highlight the potential of functional PEEK materials for bone regeneration in patients with osteoporosis.

A Brief Review on PEEK as biomaterial, Importance of Implant Design, 3D Printing and FEA in Dental Implant

The present research study seeks to provide a thorough literature evaluation on implant-based materials, implant design and application of FEA approach (Finite Element Analysis). PEEK biomaterial is the primary subject of this article. Implant design and the significance of PEEK material in future clinical applications are significant subtopics in this study. Due to its excellent physical qualities, titanium plays an essential part in the implant business. PEEK and zirconia materials appear to have promise for the future. Biomedical uses of PEEK and its composite materials in a number of different fields, including dentistry, hip implant, anterior plate fixation, crainoplasticity, knee implants, spine implants, and so forth. The implant's impact and success are greatly impacted by the prudent selection of implant biomaterial. Before the PEEK implant can replace titanium and zirconium, further research and well-controlled clinical studies are required. In this study, a number of biomaterials that were used in the implant industry will be finalized.

Optimum Material Selection for Battery Carrier System in Electric Buses

European Union has started to encourage countries to use public transportation in order to reduce air pollution and carbon emissions. Decreasing fossil fuel reserves make energy supply difficult. Vehicle exhaust emissions increase air pollution day by day. In this period when global warming is increasing in the global world, the transition to zero-emission electric vehicle production in public transportation has begun. Electric buses provide a clean, efficient and sustainable transportation alternative to diesel vehicles. One of the most important issues to consider in electric buses is the SoC (State of Charge) value of the battery, which is the range it will get from 0 to 100 when fully charged. Reducing weight in electric buses is one of the factors that increases the range value. For this reason, in the study, finite element analysis was carried out on the currently used battery carrier frame material EN10025 S355JR, alternatively aluminium 6061-T6, aluminium 7075-T6 and carbon fiber reinforced PEEK materials to lighten the vehicle weight. As a result of the analysis, 65.54% and 73.07% lightness were achieved with aluminum 6061-T6 and carbon fiber reinforced PEEK materials, respectively. When the analysis results were compared in terms of cost, manufacturability and lifetime, the most suitability for mass production was evaluated.

The effect of thermal aging on flexural strength of CAD/CAM hybrid and polymeric materials

The field of dentistry is consistently innovating with the introduction of novel hybrid and polymer materials for computer-aided design and manufacturing (CAD/CAM). It is noteworthy that the temperature within the oral cavity has a significant impact on the strength of new biomaterials utilized for CAD/CAM fabrication of fixed partial dentures (FPDs). Studies have demonstrated that alterations in intraoral temperature may significantly affect the longevity and durability of dental restorative materials. This study aimed to evaluate the flexural strength, flexural modulus, and effect of thermal aging on CAD/CAM restorative materials. Five CAD/CAM materials were investigated: nano-ceramic-hybrid (GR), polymer-infiltrated-ceramic-network (VE), polyether-ether-ketone (PK), fiberglass-reinforced epoxy-resin (CT), and Feldspar Ceramic (VB). A total of 100 bar-shaped specimens were prepared (N = 20). Each group was subdivided into thermocycling (TC) and no-thermocycling (NTC) subgroups (n = 10). All the specimens underwent a 3-point bending test. The mean flexural strengths and moduli were statistically analyzed using paired t-test, analysis of variance (ANOVA), and Bonferroni pair-wise comparison (p < 0.05). Significant differences were observed in the flexural strength (FS) and modulus (E) between the materials (p < 0.001). GR had the highest FS among tested hybrid materials. NTC CT had the highest FS (924.88 ± 120.1 MPa), followed by GR (385.13 ± 90.73 MPa), then PK (309.56 ± 46.84 MPa). The FS of brittle ceramic VB was the lowest (p < 0.001), but similar to that of PICN VE. Only resin-containing VE and CT significantly decreased in E after thermocycling (p < 0.01, p = 0.013), showing the softening effect of thermocycling on their resin matrix. It can be concluded that new hybrid materials (GR) had higher flexural strength than feldspar ceramic and other resin/polymeric CAD/CAM materials. Polymeric PEEK and GR hybrid materials were resistant to significant deleterious effects of TC. Therefore, they would be appropriate for situations with a higher stress load.

Micro-CT Marginal and Internal Fit Evaluation of CAD/CAM High-Performance Polymer Onlay Restorations

(1) Background: The use of high-performance polymers for fixed restorations requires additional studies regarding their adaptability and processing with CAD/CAM technology. This in vitro study aims to assess the marginal and internal fit of PEEK and PEKK materials using microcomputed tomography. (2) Methods: Twenty-four (n = 8) MOD onlays made of PEKK (Pekkton ivory), unmodified PEEK (Juvora medical), and modified PEEK (BioHPP) were investigated. A typodont mandibular left first molar was scanned to achieve 24 resin, 3D printed abutment teeth. The onlays were fabricated with a five-axis milling machine, and after cementation of the specimens, the marginal (MG) and internal gaps (IG) were evaluated at twelve points in the mesio-distal section and thirteen points in the bucco-lingual section using microcomputed tomography. For statistical data analysis, Wilcoxon signed-rank/paired Student t-Test, Mann-Whitney/unpaired Student t-Test, and one-way ANOVA test were applied. (3) Results: Significant differences (p < 0.05; α = 0.05) were reported between the MG and IG for each material for all three polymers and also among two materials in terms of the MG and IG (except Juvora-BioHPP). The highest IG values were recorded in angular areas (axio-gingival line angle) in the mesio-distal section for all the polymers. (4) Conclusions: For all the materials, MG < IG. The type of polymer influenced the adaptability; the lowest marginal and internal gap mean values were recorded for BioHPP. The analyzed polymer used for onlays are clinically acceptable in terms of adaptability.

Study of the interlayer bonding strength for combined 3D printing and milling of polyetheretherketone

AbstractPolyetheretherketone (PEEK) has good mechanical properties and biocompatibility for a wide range of biomedical applications. The combined 3D printing and milling process (CPMP) is a typical additive/subtractive hybrid manufacturing technique, which facilitates the rapid response for customized PEEK implants. This paper investigates the CPMP process combining fused deposition modeling printing and dry milling for PEEK materials. The results show that the bending and shearing effects of the milling cutter on the 3D‐printed part cause the machined surface to be extremely susceptible to delamination. Poor Z‐direction interlayer bonding strength at the 3D printing stage is the main cause of delamination. Therefore, the effects of 3D printing parameters (nozzle temperature, layer thickness, and bed temperature) on Z‐direction interlayer bonding strength are studied using an orthogonal experiment design method. The applicability of three 3D printing infill patterns (grid, rectilinear, and gyroid) in CPMP is compared. The results of the research show that the storage modulus is a more accurate reflection of the interlayer bonding strength in the Z‐direction than the shear strength. With a combination of parameters of a nozzle temperature of 450°C, a layer thickness of 0.1 mm, a bed temperature of 260°C and a rectilinear infill pattern, the 3D‐printed parts have significantly stronger interlayer bonding strength. Consequently, there exists almost no delamination on the milled surface.

Characterization and Assessment of PEEK/Silicon Dioxide Composite.

In the domain of dentistry, PEEK materials have been utilised as removable partial denture frameworks, implant substances, and fixed dental prostheses. Even though PEEK polymer has a low modulus of elasticity, its mechanical attributes could be fine-tuned by integrating various inorganic filler materials. The study intends to characterise and assess Nano SiO2/PEEK composite prepared by using the melt blend approach. The design of this study uses 3% SiO2 and PEEK composite made using the melt blend technique and studies their characteristics with reference to pure PEEK. The following assessments are conducted: SEM and EDX assessment with AFM investigation in addition to tensile strength test, transverse strength test, and wettability test. All data were scrutinised by SPSS software version 24 and the statistical analyses included the mean, standard deviation, and the independent sample t-test. The outcomes of this investigation pertain to the differences in characteristics of a composite of SiO2/PEEK compared with pure PEEK. The outcomes indicate that there is a statistically highly significant increase in the mean value of transverse strength was seen with the PEEK/SiO2 composite (3503.02 MPa) versus PEEK (2694.61 MPa), while there is a statistically significant decrease in the mean value of the tensile strength for PEEK/SiO2 (63.69 MPa) versus PEEK (97.62 MPa). Moreover, improvement in hydrophobic characteristics and surface roughness of PEEK/SiO2 (81.78°), (0.66 nm) versus PEEK (71.01°), (1.23 nm), respectively, thus giving more chance to composite to be investigated in human bone/implant substitution. Furthermore, the results of EDX and SEM images exhibited adequate distribution of Nano SiO2 within the PEEK matrix. There was also a statistically substantial decrease in the surface roughness and tensile strength obtained from the AFM investigation. As far as this study is concerned, a conclusion can be made that we can use 3% Nano SiO2 to prepare a composite of SiO2/PEEK by using the melt blend approach. Nano SiO2 can alter the SiO2/PEEK composite's transverse strength and reduce the hydrophobic characteristics of the surfaces with proper distribution of nanoparticles within the matrix of PEEK with less surface roughness.

Material extrusion 3D printing of polyether ether ketone in vacuum environment: Heat dissipation mechanism and performance

3D printing of PEEK materials is gaining more and more interests in numerous application fields giving consideration to both the advanced fabrication process and the excellent material properties. A vacuum environment (VAC) was utilized in material extrusion (ME) based 3D printing process for PEEK materials in this study. Two types of PEEK samples were prepared by a customized ME printer integrated into a vacuum chamber under low pressure of 100 Pa and atmosphere condition (ATM) respectively. They were compared in crystallinity, microstructures, and mechanical performance. The crystallinity exhibited an increase from 14.9% of ATM to 27.8% of VAC. The interfacial bonding quality became better with larger neck growth and molecular diffusion between adjacent beads and layers in the VAC samples and thus the reduction of voids achieved. The tensile strength and modulus of the VAC samples in different forming directions were all improved, in particular the V-90° samples, which were increased by 212.5% and 74.9% respectively. The fracture surface morphology further illustrated enhanced interlayer adhesion in the VAC samples. Based on the theoretical calculation and thermal imaging experiments of PEEK cooling process, it was concluded that the slow heat dissipation rate in VAC allowed extruded filament to maintain a high temperature state for a long time and reduce temperature gradient, facilitating both crystallization and merging of PEEK materials. As a novel technology, vacuum 3D printing process can improve interlayer bonding and warping deformation of PEEK without high ambient temperature, which is suitable for many applications, especially 3D printing in space.

Evaluation of Stress and Strain on Mandible Caused by Using “All-on-Four” System from PEEK in Hybrid Prosthesis: Finite Element Analysis

Background Hybrid prostheses have recently been used to restore the mastication mechanism. These prostheses utilize the “All on four” concept, in which four implants are inserted into the jaw bone and supported by bar. Titanium is usually used in the production of “All on four” parts due to its good mechanical properties, however, it has drawbacks such as aesthetic impairment, casting issues, stress shielding, and incompatibility with imaging techniques. These drawbacks have prompted researchers to find alternative materials (e.g. polymers). Recently, the new polymeric material PEEK, has a major role in dentistry due to its biocompatibility, shock-absorbing ability, and good mechanical and chemical properties. The density of spongy bone is expected to influence the choice of “All on four” material. Objective This work used the finite element method to conduct stress /strain analysis on a mandible rehabilitated with a hybrid prosthesis, by using PEEK in the production of “All on four” parts instead of titanium, using different densities of spongy bone. Methods 3D mandibular model with a hybrid prosthesis was constructed, then “All on four” parts were stimulated with titanium and PEEK materials under different mastication mechanisms. Results PEEK material reduced the stresses and strains on bone tissues and increased the mucosal stress compared to titanium. Consequently, this material was recommended to be used in producing “All on four” parts, especially in the low-density model. Conclusions The density of spongy bone influenced the choice of “All on four” material. Moreover, further researches on PEEK implants and abutments are required in near future.

Surface roughness and color changes of dental PEEK related to staining beverages and cleaning methods

Considering that the microstructure, texture and surface characteristics are relevant factors that could affect the appearance and resistance of a material, the study aims to evaluate in vitro, the surface roughness development and color changes related to staining beverages and cleaning methods after simulated periods of clinical use. The discoloration processes of PEEK materials are caused by intrinsic or extrinsic factors and still require elucidation. Three types of unmodified or modified PEEK CAD/CAD materials were selected for investigation: Finoframe, Juvora medical and BioHPP-a reinforced material. Four different staining media were involved: hot coffee, black tea, cold juice, and distilled water as control. For staining thermal cycling was performed between a hot coffee/tea bath (55 °C) and a bath filled with distilled water (37 °C), respective between a cold juice bath (5 °C) and a bath filled with distilled water (37 °C). For cleaning, a chemical method and mechanical brushing were selected. Simulated periods of clinical use were taken into consideration. Roughness measurements (Ra and Rz) were done after each period. Color changes (ΔE*) were calculated based on the CIE L*a*b* color system. Statistical analyses were performed, paired t-Test for comparisons between the means and Spearman correlations to assess relationships between roughness and color changes. After staining beverages, a significant decreased in Ra values for all three materials that were immersed in juice and, for B and F in tea, were measured. Perceivable changes have been identified for J in coffee and for B in tea. After brushing, Ra significant decreased for J, in all immersion environments and no perceivable color changes were reported. The chemical cleaning caused a significant decrease in surface roughness values for B and F, in all immersion environments and color changes were perceivable for J in juice. Surface characteristics were affected by staining, mechanical and chemical cleaning; during the study, no marked color changes of PEEK were detected.

One-step rapid preparation of superhydrophobic peek with mechanical, and chemical stability

The superhydrophobic surface has the characteristics of self-cleaning, anti-corrosion, and drag reduction. Peek materials are resistant to corrosion, abrasion, and hydrolysis. Superhydrophobic peek combined with the two has attracted widespread interest. Herein, a fast and inexpensive method was presented to fabricate superhydrophobic peek with mechanical, chemical, high-temperature, hot-water, and high-pressure water impact stability. For the first time, the periodic fringe morphology with a micro-nano hierarchical structure was processed on the surface by a nanosecond laser so that the surface of the peek became super-hydrophobic. Robustness was promoted when performing various mechanical stability tests such as sandpaper abrasion, sonication, static pressure, and tape peel test. The superhydrophobic peek surface still had good chemical stability and had excellent repulsion to droplets with pH = 1–14. The surface was resistant to high-temperature, hot-water, and high-pressure water impact. These stated features reveal the convincing potential of the method to simultaneously address robustness, flexibility, and adaptability.

An Updated Review of Salivary pH Effects on Polymethyl Methacrylate (PMMA)-Based Removable Dental Prostheses.

Salivary pH is a neglected factor that may affect the performance of removable dental prostheses (RDP). This study aimed to review literature in reference to the role of salivary pH on the performance of RDP and materials used for their fabrication. From January 1990 until December 2021, a search was done on PubMed, Scopus, and Web of Science databases using removable dental prostheses, salivary pH, PMMA, Denture base, and physical properties as keywords. Articles that met the inclusion criteria (full-length articles have investigated the effect of salivary pH on RDP materials in vitro and in vivo) were included. Out of 433 articles, 8 articles that met the inclusion criteria were included. All studies used artificial saliva with different salivary pH ranging between 3 and 14. Two articles investigated the role of salivary pH on the cytotoxicity of denture base resins and soft liner. One article studied the durability and retention of attachments, one article analyzed the performance of PEEK materials, one article researched the fatigue resistance of a denture base, one article investigated the corrosion of RPD framework cast and milled Co–Cr, one article studied the strength and clasp retention and deformation of acetal and PEEK materials, and one evaluated changes in mass and surface morphology of CAD–CAM fiber-reinforced composites for the prosthetic framework. Different salivary pH affected all included materials in this review except PEEK materials. The most adverse effect was reported with alkaline and acidic; however, the acidic showed the most deterioration effect. Salivary pH has a role in the selection of material used for RDP fabrication.

Thermal-radiation aging on oriented poly(ether-ether-ketone) sheets

As a special engineering material, poly(ether-ether-ketone) (PEEK) is widely used in various safety facilities of nuclear power plants and is susceptible to the long-term cumulative effects of many complex factors. Among them, heat and irradiation are two key accompanying factors that accelerate the degradation of PEEK materials. Long-term exposure to heat and irradiation can lead to cracking, cross-linking, and oxidation reactions of PEEK materials, impairing material properties, reducing device and operational reliability, and even shortening service life. Therefore, it is very important to study its thermal-radiation aging law for its material service optimization. In this study, PEEK sheets with different tensile orientations were irradiated by a cobalt-60 irradiation source in an air atmosphere at 70 °C, and the effect of thermal-radiation on the properties of PEEK sheets was studied. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and universal tensile machine were used to investigate the effect of absorbed dose on the crystalline properties, thermal stability, mechanical properties and surface morphology of oriented PEEK sheets in the direction of force (horizontal direction) and perpendicular to the direction of force (vertical direction). Results showed that the physicochemical properties of the oriented PEEK sheets were changed under the synergistic effect of temperature, air, and irradiation. Within the absorbed dose range, with the increase of absorbed dose from 0-2500 kGy, the crystallinity of the sample first increased and then decreased. Due to the predominance of chain scission in the aging process, the crystallization temperature and melting temperature of the sample increased, while the thermal stability decreased. Elongation at break and tensile strength decrease with increasing absorbed dose.

Fabrication and biological evaluation of polyether ether ketone(PEEK)/bioceramic composites

The repair of vascularized bone defects represents a significantly clinical challenge, and vascular regeneration is one of the necessary factors to promote bone tissue regeneration. To effectively repair large bone defects, new bone tissue must regenerate with a rich vascular network. Therefore, the development of biomaterials that can promote the regeneration of vascularized bone tissue is currently receiving attention from researchers. In this study, Li–Ca–Si bioceramics (LCS) containing Li, Ca, and Si elements was developed, then LCS was compounded with PEEK to prepare PEEK+10% LCS, PEEK+20% LCS, PEEK+30% LCS, and the effect of LCS-PEEK composite biomaterials on the proliferation and angiogenic ability of human umbilical vascular endothelial cells (HUVECs) further explored by Cell Counting Kit-8 (CCK-8), scanning electron microscope (SEM), quantitative real-time PCR (QPCR), Western Blotting and enzyme linked immunosorbent assay (ELISA). The results showed that HUVECs inoculated on 30%LCS ​+ ​PEEK material exhibited the best proliferation ability. And the adhesion ability of endothelial cells on PEEK gradually increased with the increase of LCS contents. Furthermore, the angiogenic ability of HUVECs on LCS-PEEK composites was examined using QPCR and Western blotting, and the results showed that the expression of angiogenic-related genes and proteins of HUVECs on PEEK composites gradually increased with increasing LCS concentration. These results demonstrated that the angiogenic ability of HUVECs was effectively stimulated by LCS-modified PEEK materials. The present results indicate that the PEEK material can be modified with bioceramics to promote angiogenesis, and this study lay the foundation for the subsequent development of scaffolds that promote vascularized bone tissue regeneration.

Surface Characteristics and Color Stability of Dental PEEK Related to Water Saturation and Thermal Cycling.

(1) Background: The study was undertaken to evaluate the surface characteristics, microhardness, and color stability of PEEK materials related to water saturation and in vitro aging. (2) Methods: Custom specimens of unmodified and modified PEEK CAD/CAM materials were investigated: BioHPP, a ceramic reinforced PEEK, and Finoframe PEEK and Juvora medical PEEK, 100% PEEK materials. Forty-eight plates were sectioned in rectangular slices. The specimens were immersed in distilled water at 37 °C for a period of 28 days, and then subjected to aging by thermal cycling (10,000 cycles). Surface roughness was measured with a contact profilometer; nanosurface topographic characterization was made by Atomic Force Microscopy; Vickers hardness measurements were performed with a micro-hardness tester; color changes were calculated. All registrations were made before immersion in water and then subsequently once a week for 4 weeks, and after thermocycling. (3) Results: The studied reinforced and unfilled PEEK materials reached water saturation after the first week of immersion, without significant differences between them. The most affected from this point of view was the reinforced PEEK material. Thermocycling induces a significant increase inmicroroughness, without significant differences between the studied materials. In relation to the nanosurface topography and roughness, the reinforced PEEK material was the least modified by aging. The color changes after 4 weeks of water immersion and one year of simulated in vitro aging ranged from extremely slight to slight, for all materials. (4) Conclusions: Water absorption was associated with a decrease in microhardness. Surface characteristics are affected by water immersion and thermocycling. Perceivable or marked color changes of the materials were not detected during the study.

Static, fatigue and stress-shielding analysis of the use of different PEEK based materials as hip stem implants

Abstract There is a possibility that hip joints may become dysfunctional due to age, wear or some accidents, and in this case they need to be replaced with hip implants. However, after conventional hip stem implantation, the load transferred to the bone usually decreases due to the high stiffness of the metallic (most commonly Ti6Al4V, CoCr or stainless steel) hip stem implant, and as a result, mineral loss occurs in the bone which weakens. On the other hand, PEEK is an advantageous material with its low cost, ease of production, corrosion resistance and biocompatibility. More importantly, it has the potential to be a good alternative to metallic materials in load-bearing bone replacements, thanks to its mechanical properties and density close to that of the bone. In this study, hip stem implants having three different commercial PEEK materials and four different metallic main spar designs were modeled. Their behavior under static and dynamic loading conditions was analyzed according to ASTM-F2996-20 and ISO-7206-4:2010 standard test methods, and the stress-shielding effect of hip stems modeled as implanted into the femur was simulated using ANSYS commercial finite element analysis software. According to the results, it was observed that CFP based hip stem models meet the five million life time criteria and increase the stress on the femur bone by up to 57%.

Investigation of the Damping Capabilities of Different Resin-Based CAD/CAM Restorative Materials.

The aim of the present study was to evaluate and quantify the damping properties of common resin-based computer-aided design and computer-aided manufacturing (CAD/CAM) restorative materials (CRMs) and assess their energy dissipation abilities. Leeb hardness (HLD), together with its deduced energy dissipation data (HLDdis), and loss tangent values recorded via dynamic mechanical analysis (DMA) were determined for six polymer, four composite, and one ceramic CRM as well as one metal. Data were statistically analyzed. Among resin-based CRMs, the significantly highest HLDdis data were detected for the fiber-reinforced composite FD (p < 0.001) directly followed by the filler-reinforced Ambarino High Class (p < 0.001). The significantly lowest HLDdis values were observed for the polymer-based CRM Telio CAD (p < 0.001). For loss tangent, both PEEK materials showed the significantly lowest data and the polymer-based M-PM the highest results with all composite CRMs in between. HLDdis data, which simultaneously record the energy dissipation mechanism of plastic material deformation, more precisely characterize the damping behavior of resin-based CRMs compared to loss tangent results that merely describe viscoelastic material behavior. Depending on material composition, resin-based CRMs reveal extremely different ratios of viscoelastic damping but frequently show enhanced HLDdis values because of plastic material deformation. Future developments in CAD/CAM restorative technology should focus on developing improved viscoelastic damping effects.

Study and numerical analysis of Von Mises stress of a new tumor-type distal femoral prosthesis comprising a peek composite reinforced with carbon fibers: finite element analysis

Research on carbon-fiber-reinforced polyetheretherketone (CF-PEEK/CFR-PEEK) as a bone tumor joint prosthesis remains limited. Herein we numerically determine the feasibility of CF-PEEK material containing 30% Wt carbon fiber (CF30-PEEK) as a material for the dual-action tumor-type distal femoral prosthesis. Use CT scan method to build a complete finite element model of the knee joint. Simulate the resection of the distal femoral tumor, and then reconstruct it with the dual-action tumor-type distal femoral prosthesis. The femoral condyle and extension rod components were simulated with cobalt chromium molybdenum (CoCrMo), PEEK and CF30-PEEK materials respectively. When simulating the standing state, a vertical stress of 700 N is applied to the femoral head. When simulating the squatting state, a vertical stress of 2800 N is applied to the femoral head. The displacement and rotation angle of each node of the distal tibia are fully restrained in three directions (X-axis, Y-axis, Z-axis). We examined the stress magnitude, stress distribution, and stability of the prosthesis and each of its components by means of finite element analysis (FE analysis). The FE analysis results show: after replacing the distal femur and the extension rod with CF30-PEEK material, the stress is still evenly distributed, and the average stress is significantly reduced. In addition, the stability is similar to CoCrMo material. Therefore, CF30-PEEK is an appropriate material for this type of prosthesis.