Grindability of extruded and 3D Printed PEEK Samples

Treatment for intervertebral disc degeneration involves the complete removal of the disc and the fusion of two adjacent vertebrae via a biocompatible implant. The implant must be capable of both supporting the mechanical forces experienced by the spine, as well as promoting bone growth. PEEK has been shown to perform well in spinal fusion surgeries, but can face challenges with osseointegration as it is highly hydrophobic. Post-processing techniques have been considered as a method to improve the osseointegration of PEEK spinal cages, with ultraviolet (UV) light assisted functionalization being one possible method. The addition of calcium phosphate to bone scaffolds has been shown to increase osseointegration due to similarities to hydroxyapatite, a major inorganic component of bone. We investigated the use of UV-assisted functionalization to add a calcium phosphate layer to PEEK samples in order to improve osseointegration. PEEK samples with dimensions of 10x10x1 mm were obtained via fused filament fabrication/3D printing and submerged in simulated body fluid (SBF). Samples were exposed to a 2W/cm2 UV light for six hours, and then placed in a water bath set to 37°C for a total of 72 hours, with SBF being changed after 48 hours. After functionalization, the PEEK samples were washed with DI water and dried. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was performed on the functionalized samples, control PEEK samples that were not treated, and control samples that were soaked in SBF for 72 hours but were not exposed to UV light. Images of the surface of the functionalized samples and controls were obtained using a scanning electron microscope (SEM) (Zeiss Supra 50VP) with EDS (Oxford) capabilities. SEM/EDS analysis of UV functionalized PEEK samples showed morphological surface changes as well as calcium and phosphorous on the surface of the material. The functionalized PEEK samples were found to have a molar Ca:P ratio of 1.69, while natural hydroxyapatite has a molar ratio of 1.67. EDS analysis of non-functionalized control samples found no calcium or phosphorus. FTIR results found that the non-functionalized PEEK samples and the PEEK samples that were soaked in SBF but were not treated by UV were nearly identical, with no calcium phosphate. For functionalized samples, notable peaks were observed at 560 and 600 cm-1, and between 1000 and 1100 cm-1, which has shown to be a phosphate group. Analysis of functionalized PEEK revealed that UV-assisted functionalization successfully applied a layer of calcium phosphate material to the surface of the sample. While the goal was to obtain a layer of hydroxyapatite in order to promote osteoblast adhesion, the observed ratios of calcium to phosphate obtained via EDS are more likely to indicate an amorphous calcium phosphate layer. The addition of this layer to the PEEK surface is believed to enhance the osseointegration of newly developed biomedical implants. Keywords: 3D printing, calcium phosphate, hydroxyapatite, osteoblast, PEEK, Polyether ether ketone, UV functionalization

Tailoring the biologic responses of 3D printed PEEK medical implants by plasma functionalization

Evaluation of Strength of Different Resin Materials Used in Evaluation of Strength of Different Resin Materials Used in Overdenture

ABSTRACTPolyetheretherketone (PEEK) medical devices have been shown to perform well as permanent implants, but the hydrophobicity of PEEK limits its osseointegration ability. Postprocessing techniques are used to improve osseointegration, with ultraviolet (UV) light‐assisted functionalization being one possible method. We hypothesized that UV irradiation of PEEK could be used to graft hydroxyapatite (HAp) to its surface. PEEK samples were created via fused filament fabrication and submerged in 2× simulated body fluid (SBF). Samples were exposed to a 2 W/cm2 UV light for 6 h and then placed in a water bath set to 37°C for a total of 72 h. After being washed with deionized water and dried, attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) was performed on the functionalized samples, control PEEK samples that were not treated, and control samples that were soaked in SBF for 72 h but were not exposed to UV light. Images of the surface of the functionalized samples and controls were obtained using a scanning electron microscope with energy‐dispersive spectroscopy. An in vitro cell study using mouse preosteoblasts was performed to verify if functionalization improves osteoconduction. Normalized alkaline phosphatase activity was used as a marker for osteogenic activity. Analysis revealed that UV‐assisted functionalization successfully applied a layer of calcium phosphate material to the surface of the PEEK. After culturing functionalized surfaces in vitro, the addition of calcium phosphate was found to significantly improve osteogenic activity when compared to nonfunctionalized PEEK samples after 7 and 14 days.

Introduction - Thermoplastic polymers have many potential uses in medicine and dentistry as an alternative to the commonly used titanium. Since the 1980s, polyaryletherketones (PAEKs) have been increasingly employed as biomaterials for trauma, orthopedic, and spinal implants. Due to several advantages of these materials, metal-free restorations are performing an important role in current medical therapies. PEEK is biologically inert and various surface modifications are given to increase its osseointegration potential of PEEK, Acid etching is the most simple and cost effective method of treatment. The aim of this study is to evaluate the surface roughness and wettability of 2 different acid etching techniques of PEEK samples - Magnetic stirring and ultrasonic. Material and methods - PEEK samples thicknesses of 2 mm and diameters of 15 mm was used in the study and the sulfonation procedure was done magnetically and ultrasonically for 6 mins and samples were rinsed with acetone for 10 mins, washed with deionized water for 10 mins and finally dried at 37°C. The results of the study were subjected to statistical analysis in SPSS software version 23.0. Independent t test was performed for the parameters. Results - when comparing 2 groups magnetic stirred sulfonated PEEK (MSPEEK) and Ultrasonic PEEK (USPEEK) results showed statistically significant difference present. (P < 0.05) in surface roughness and in wettability no significant difference is seen (P > 0.05). Conclusion - The literature suggests that PEEK offers an alternative to titanium, especially in cases of orthopedics and trauma. Its properties make it an interesting material in Dental implantology to be performed with CAD-CAM. Further studies are required to obtain sufficient scientific evidence to enable its uses as a permanent material.

In the present study, the antimicrobial peptide nisin was successfully conjugated onto the surface of sulfonated polyetheretherketone (SPEEK), which was decorated with graphene oxide (GO) to investigate its biofilm resistance and antibacterial properties. The PEEK was activated with sulfuric acid, resulting in a porous structure. The GO deposition fully covered the porous SPEEK specimen. The nisin conjugation was accomplished using the crosslinker 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) through a dip-coating method. The surface micrographs of the SPEEK-GO-nisin sample indicated that nisin formed discrete islets on the flat GO surface, allowing both the GO and nisin to perform a bactericidal effect. The developed materials were tested for bactericidal efficacy against Staphylococcus aureus (S. aureus). The SPEEK-GO-nisin sample had the highest antibacterial activity with an inhibition zone diameter of 27 mm, which was larger than those of the SPEEK-nisin (19 mm) and SPEEK-GO (10 mm) samples. Conversely, no inhibitory zone was observed for the PEEK and SPEEK samples. The surface micrographs of the bacteria-loaded SPEEK-GO-nisin sample demonstrated no bacterial adhesion and no biofilm formation. The SPEEK-nisin and SPEEK-GO samples showed some bacterial attachment, whereas the pure PEEK and SPEEK samples had abundant bacterial colonies and thick biofilm formation. These results confirmed the good biofilm resistance and antibacterial efficacy of the SPEEK-GO-nisin sample, which is promising for implantable orthopedic applications.

This study aimed to Modify the PEEK surface using Fractional CO2 laser in different range of parametersto change the surface topography regarding roughness and wettability to enhance osseointegration. A PEEKblock (Ceramill PEEK 98X20 N -JUVORA dental innovations, UK) was used to prepare substrate. By CADCAM system, PEEK was cut into discs (2 mm thickness and 10 mm diameter). the discs were smoothed bysilicon carbide paper of 500 grit and a rotation motion, polishing machine at 200 rpm for one minute usedto polish the discs, finally cleaned with ethanol alcohol using ultrasonic cleaner. Different parameters weretested to study their effects on PEEK surface; therefore, several trails were done using Fractional CO2 laserdevice. Surfaces of the irradiated PEEK discs were examined microscopically at different magnificationpower. Then SEM was used. Then, PEEK samples were scanned by (EDS). Range of powers were used (2,4, 6, 8, 10, 12) W The distance between spots was 0.2mm and 0.2 ms pulse duration to ensure maximumcoverage of laser effect. The energy range was (4 - 25) which was n’t enough to produce any effect. To testthe effect of pulse duration different values were also studied starting from 0.2ms then increase the pulseduration. 0.4,0.6,0.8 ms to increase the energy per pulse accordingly. Starting from short pulse durationup to 0.6ms there was no effect even when the power increased. At 0.8 ms pulse duration, the effect wasrecognized on the specimen surface. The collected data of previous trials direct the operator to reduce pulseduration to have best criteria, including surface roughness, wettability, without carbonization or cracks.Conclusions: Successful modification of PEEK surface can be done with fractional CO2 laser. Laserparameters as power, pulse duration, distance between spotes and number of scans are key factors induceddifferent range of effect considering material’s properties.

Aim PEEK (poly-ether-ether-ketone) is an innovative thermoplastic polymeric biomaterial used in Maxillofacial Surgery. As opposed to metallic implants, PEEK implants can be 3D-printed specifically for patients and do not suffer stress shielding effects- a major cause of implant failure. This investigation aimed to compare mechanical integrity and biocompatibility of modern 3D-printed PEEK implants against traditionally produced Milled-PEEK implants and metallic biomaterials e.g., Titanium. Method Fused-deposition-modelling and non-CNC Milling were used to produce ASTM/ISO-designed PEEK samples. Samples were designed and produced using the Apium P155 FDM-3D-printer, Fusion 360 and Simplify3D software. Fracture Toughness KIc, Tensile Strength, Vickers micro-hardness and 3-point flexural strength tests were performed. Cell adhesion on sandblasted 3D-printed PEEK was evaluated by culturing primary human endothelial cells and osteoblasts (HUVEC, HOBS) and evaluating cell growth. Results Milled PEEK had higher tensile strength (p=0.022), higher flexural strength (p<0.0001) and higher fracture toughness (p=0.003) than FDM-printed PEEK. However, FDM-printed PEEK demonstrated higher microhardness than Milled PEEK (p=0.014). Both FDM and Milled PEEK showed mechanical strength values in normal ranges of cortical bone, and close to ranges of alternative bone-replacement biomaterials. Both HOBS and HUVEC demonstrated strong adhesion to PEEK with >95% viability. Conclusions 3D-printing of PEEK is an emerging technology with advantages over milling and metallic biomaterials in implant production. Nonetheless, this manufacturing modality may produce 3D-printed PEEK devices with lower mechanical resistance parameters compared to milled PEEK, but with values compatible with natural bone. Sandblasting is a modality to create uniform micro-rough surfaces potentially enhancing osseointegration of PEEK implants with host tissue.

Study of the effect of electric field on positron annihilation parameters in polymers

Structure-property-processing relationship of ethanol solvent exchanged PEEK

Abstract19NMR spectroscopy has been performed on PEEK samples in sulphuric acid, revealing that most chain ends are fluorine. Different chemical shifts have been observed on sulphonated samples due to already demonstrated long range shielding effects. The method appears suitable for Mn determination.Substitution of F chain ends, followed by 19NMR, appeared feasible leading to alkaline sulphonate end groups. Ionic chain ends associations act as seeds for nucleation. Fast crystallizing PEEK and PEK are thus obtained. This is a new demonstration of the concept of Chemical Nucleation.

The erosive wear and corrosion resistance of three types of flame spray-deposited polymer coatings was analyzed. The erosive wear test was performed in slurry pot tester with rotational movement using distilled water and mix quartz particles (300 g/l). Two impact angles of the particles were used, reaching 4.15 m/s average impact velocity. Corrosion resistance of the polymer coatings and degradation behavior were investigated by electrochemical impedance spectroscopy in a solution of 0.5 M sodium chloride at room temperature for a total immersion time of 1 year. The interpretation of the results was made according to the Bode plot. It is proven a better slurry erosion wear performance for PEEK and PA12 coatings when the particles impact at 90° angle. For impact angle of 30°, there is no significant difference in the erosion performance of PEEK, PEI, and PA12 coatings. No major changes occurred in the impedance module for PA12 and PEEK samples, indicating that these coatings can protect the steel substrate for extended periods of time. The lower PEI performance is believed to be related to the improper choice of spraying parameters, as the spray conditions were kept constant for the three feedstock materials.

Chemical modification of poly(ether ether ketone) for size exclusion chromatography at room temperature: 2. On the reliability of the derivatization procedure for PEEK molecular-mass determination—application to PEEK-carbon fibre composite

Objectives: This study aimed to evaluate the bacterial accumulation on the inner surface of secondary telescopic crowns constructed from zirconia and PEEK Materials. Materials and methods: Three pieces of each of the tested materials (PEEK &Zirconia) were incubated in bacterial suspensions that contained 1X106 cfu/ml of bacteria (Streptococcus mutans ATCC 35668 or Lactobacillus acidophilus ATCC 4356) and the surface examined using a scanning electron microscope. Results: Bacterial counting showed statistically significant higher values in the PEEK samples with both types of bacteria. A biofilm mass containing a large number of bacilli and little number of cocci was observed on the surface of the PEEK material while aggregates of bacilli and little amount of cocci appeared without biofilm mass on the surface of the zirconia material. Conclusion: PEEK secondary telescopic crowns showed more bacterial accumulation with biofilm formation than zirconia secondary telescopic crowns.

PEEK-based implant materials have gained increasing attention as an alternative to titanium due to their biocompatibility and bone-like elasticity. However, PEEK's surface quality and wear resistance are lower than those of metals. This study aimed to enhance the bioactivity and surface quality of PEEK by coating it with silver and copper nanoparticles synthesized via a green method using Equisetum telmateia Ehrh. extract. PEEK samples (Ø 25 mm, 3 mm thick) were coated with single and double layers using spray (airbrush-spray) and drop-coating methods. Comprehensive analyses including SEM, EDX, FT-IR, UV-Vis, surface roughness, release studies, antioxidant and cytotoxicity activity, and antibacterial tests were conducted on the coated samples. The results demonstrated that AgNPs and CuNPs coatings significantly improved the surface quality of PEEK. SEM analysis revealed particle sizes ranging from 48 to 160 nm for AgNPs and 50-135 nm for CuNPs, with superior dispersion obtained using the airbrush-spray method. Surface roughness measurements showed a reduction of 17-33% for AgNPs-coated samples and 7-15% for CuNPs-coated samples compared to uncoated PEEK, with airbrush-spray coatings providing smoother surfaces. Antioxidant activity tests indicated that AgNPs provided 35% higher antioxidant activity compared to CuNPs. Additionally, antibacterial tests revealed that AgNPs exhibited a higher zone of inhibition (up to 14 mm for S. aureus and 18 mm for E. coli) compared to CuNPs, which exhibited zones of 8 mm and 10 mm, respectively. This study concludes that green-synthesized AgNPs, in particular, enhance the bioactivity and surface properties of PEEK, making it a promising material for biomedical applications such as infection-resistant implants.