Use Of PEEK Research Articles

Current Evidence on the Use of PEEK as Implant Abutment Material

Current Evidence on the Use of PEEK as Implant Abutment Material

The Use of PEEK in Implantology: A Narrative Review

Purpose: The present paper reviewed the literature on PEEK and its applications in implant dentistry. Materials and Methods: In vivo in human and animal models, in vitro studies, case reports and cases series that evaluated the use of PEEK in implantology were included in this narrative review. Results: There are ever more studies on the best way to apply PEEK in implant dentistry. The mechanical properties of PEEK, which are close to that of bone tissue, are its strength. However, its low osteointegration capacity and surface bio-inertness have limited its clinical translation. PEEK cannot be used as a dental implant. However, some studies have shown that this material could be used for guided bone regeneration; implant abutments for interim restorations, impression devices, or a crown framework. Conclusion: Further research, including in vivo and clinical studies, is needed to determine the feasibility, long-term performance and appropriate indication for this biomaterial.

Light‐Driven Shape Memory of 3D‐Printed PEEK for Programmable Actuations

AbstractRemotely controllable actuation of engineering polymers is highly demanded in the fast‐developing intelligent society. Here, this work demonstrates that the programmable shape memory of 3D‐printed poly(ether ether ketone) (PEEK), which is an excellent engineering material, could be driven by both ultraviolet (UV) light and natural sunlight. The shape recovery ratio reaches 97.6% and could be finely regulated by defining the sample thickness, shape programming, way of placement, and light intensity. Light‐induced continuous, sequential, and programed actuations (shape recovery) are further realized in various 3D‐printed PEEK structures. Meanwhile, the coating of a thin layer of gold is proven to be effective in anti‐UV oxidation and the enhancing of shape recovery. Moreover, natural sunlight during daytime is demonstrated to be able to induce the shape recovery of 3D‐printed PEEK in outdoor environment. The work here can pave the way for the use of PEEK as a smart material in the fields such as aerospace and intelligent industry.

ZeroExpander: Metal-free automatic palatal expansion for special-needs patients.

The aim of this paper is to illustrate a new concept for approaching maxillary expansion in paediatric orthodontics with a metal-free fixed automatic appliance in special-needs patients. The ZeroExpander is a complete CAD-CAT full digital and automatic metal-free fixed device. It is designed to expand the maxilla in a pre-programmed automatic way using deciduous teeth as anchorage. Two cases of growing patients with a narrow upper arch are illustrated to present this innovative system, one in complete deciduous dentition and the second in mixed dentition. Both patients were successfully treated with palatal expansion. In the first case we present the use of PEEK, and in the second one the use of PA12. The ZeroExpander, fabricated using metal-free technopolymers and anchored on deciduous teeth, proved to be comfortable and efficient in treating palatal transverse deficiency, without the need of any compliance, even in young patients who must periodically undergo MRI.

Surface-tethering of methylated polyrotaxanes with 4-vinylbenzyl groups onto poly(ether ether ketone) substrates for improving osteoblast compatibility.

Poly(ether ether ketone) (PEEK) is a high-performance thermoplastic used for several industrial applications due to its excellent mechanical properties. However, the use of PEEK is limited to dental materials because of its poor implant-bone integration. In the present study, methylated polyrotaxanes (MePRXs) with 4-vinylbenzyl groups, which are supermolecules composed of methylated α-cyclodextrins and poly(ethylene glycol) chains end-capped with 4-vinylbenzyl groups, were covalently tethered onto PEEK surfaces using photo-induced polymerization to improve their osteoblast compatibility. The surface-tethering of MePRXs onto PEEK surfaces was confirmed by analyzing their attenuated total reflectance Fourier transform infrared spectra and contact angles. When mouse preosteoblasts were cultured on the MePRX-PEEK and bare PEEK surfaces, the MePRX-PEEK surfaces showed significantly better proliferation and osteoblast differentiation than the bare PEEK surfaces. These results suggest that surface modification of PEEKs using MePRXs improves their osteoblast compatibility.

PEEK in dentistry, properties and application areas

Aim: PEEK is a widely accepted material in medicine and dentistry. The aim of our study is to define and summarize the application areas of PEEK in dentistry. A retrospective literature research was conducted using the keywords ‘polyetheretherkethone’, ‘PEEK’, ‘dentistry’, ‘dental’,’ implant’, on the Pubmed and Google Scholar databases. The relevant articles were analyzed and summarized. In this review, the structure, properties and application areas of PEEK are explained.
 Conclusion: PEEK can be used in the biomedical field due to its excellent chemical and mechanical properties. Thanks to its bone-like elasticity modulus it can be used as an implant material, fixed and removable prostheses, obturators, pediatric dentistry, and orthodontics. In addition, PEEK is an alternative to metals due to its non-allergic and aesthetically acceptable properties. Nevertheless, improving PEEK's properties and increasing biocompatibility is a challenging process. It is expected that the use of PEEK in dentistry will increase due to the modifications applied.
 
 How to cite this article:
 Akay C, Ersöz MB. PEEK in dentistry, properties and application areas. Int Dent Res 2020;10(2):60-65.
 https://doi.org/10.5577/intdentres.2020.vol10.no2.6
 
 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

115. Clinical outcomes of a PEEK-on-ceramic total disc replacement: data from 3 sites participating in the single-level cervical FDA IDE trial

BACKGROUND CONTEXT To date, good results have been reported for a variety of cervical total disc replacements (TDR). These devices have most commonly been made of metallic end plates with a plastic core. A few metal-on-metal devices have also been described. The use of PEEK for spinal implants continues to increase, primarily due to its mechanical properties and positive imaging properties (ie, no metallic artifact on MRI or CT). A TDR was designed with titanium-coated PEEK end plates and a biconvex zirconia toughened alumina ceramic core. PURPOSE The purpose of this study was to evaluate the preliminary results of 3 sites participating in the single-level Investigational Device Exemption (IDE) study for a PEEK-on-ceramic TDR. STUDY DESIGN/SETTING This is a prospective study evaluating the cervical TDR using a non-concurrent historical control. PATIENT SAMPLE The device was implanted into 56 patients at 3 of 16 sites participating in the FDA IDE trial for single-level cervical disc degeneration. Twelve-month data were available for 49 patients and 24-month data available for 23 patients. OUTCOME MEASURES Outcome measures included the Neck Disability Index (NDI), visual analog scales (VAS) assessing neck and arm pain, and the Dysphagia Handicap Index. Radiographic assessments of the operated level included disc height and flexion/extension range of motion. METHODS Patients enrolled in the trial received the Simplify PEEK-on-ceramic TDR. Evaluations were conducted prior to surgery and within 2 weeks, 6 weeks, and 3, 6, 12 and 24 months after surgery. Radiographs were analyzed by an independent lab specializing in image assessment. RESULTS Mean NDI scores improved significantly (p CONCLUSIONS Preliminary results of this IDE study found the PEEK-on-ceramic disc replacement produced significant improvements in pain and function scores, which were maintained through the 12- and 24-month follow-up. Range of motion and disc height of the operated segment were significantly increased after surgery and maintained. The values were similar to those reported in other FDA IDE trials for cervical TDR. FDA DEVICE/DRUG STATUS Simplify Disc (Investigational/Not approved)

Facile Surface Modification Method for Synergistically Enhancing the Biocompatibility and Bioactivity of Poly(ether ether ketone) That Induced Osteodifferentiation.

Poly(ether ether ketone) (PEEK) is a promising material in biomedical engineering due to its suitable mechanical properties and excellent chemical resistance and biocompatibility. However, the biological inertness of PEEK limits its applications. In this study, we developed a facile approach of immersion to generate a biocompatible and bioactive PEEK that induced osteodifferentiation. First, micropores on the surface of PEEK were introduced by concentrated sulfuric acid and subsequent water immersion, followed by the hydrothermal treatment to reduce residual sulfuric acid. Subsequently, the sulfonated PEEK surface was activated by the oxygen plasma treatment and then coated with a poly(dopamine) (PDA) layer by immersion into the dopamine solution. Finally, the tripeptide Arg-Gly-Asp (RGD) was integrated onto the PDA-coated surface of PEEK by immersion into the RGD peptide solution. The surface characteristics (physical chemistry and biological properties) and the ability to form bonelike apatite were systematically investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle analysis, the Archimedes' fluid saturation method, ellipsometry, a quartz crystal microbalance with dissipation monitoring, cell proliferation, real-time reverse transcription polymerase chain reaction analysis, alizarin red staining, immunocytochemistry staining, and simulated body fluid immersion. Collectively, the modified PEEK showed a significantly improved ability to promote cell proliferation, osteogenic differentiation, and bonelike apatite formation in vitro as compared to the PEEK control. These results demonstrate that combined facile surface modifications for PEEK enhance its bioactivity and biocompatibility, and induce osteodifferentiation. This study presents a strategy for broadening the use of PEEK in the application of orthopedic implants and could be industrially scalable in future.

Mechanical and thermal properties and cytotoxicity of Al2O3 nano particle-reinforced poly(ether-ether-ketone) for bone implants.

Weak mechanical properties and mismatching of elastic modulus to human bone restricts the use of PEEK as a bone implant material. By introducing reinforcing particles in polymers, composite material properties could be tailored to meet specific design requirements. In this work, composite materials with PEEK as a matrix and Al2O3 as reinforcing fillers were prepared by an injection molding method. Subsequently, the effects of different particle sizes (30 nm, 0.2 μm, 5 μm) and distinct contents (2.5 wt%, 5.0 wt%, 7.5 wt%, 10.0 wt%, 12.5 wt%, 15.0 wt%) of Al2O3 powder on the mechanical properties of the composites, such as tensile strength, bending strength, impact strength, Vickers hardness and modulus, were investigated by an electronic universal testing machine. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to compare the thermal properties of composites with different proportions. Besides, the cross-section fractography of the composites after the tensile strength test was characterized by scanning electron microscopy (SEM) to analyze the interface bonding effect. Moreover, mouse fibroblast L929 cells were used for cytotoxicity testing of CCK-8 kit to evaluate cell compatibility of the composite in vitro and cell morphology was observed by inverted fluorescence microscopy. Based on the obtained results, Al2O3 reinforcement enhanced many properties in some aspects, which makes the Al2O3/PEEK composite one of the most promising candidates for human bone implantation, reconstruction, orthopedic and trauma applications.

Optimization of Feasibility Stage for Hydrogen/Deuterium Exchange Mass Spectrometry.

The practice of HDX-MS remains somewhat difficult, not only for newcomers but also for veterans, despite its increasing popularity. While a typical HDX-MS project starts with a feasibility stage where the experimental conditions are optimized and the peptide map is generated prior to the HDX study stage, the literature usually reports only the HDX study stage. In this protocol, we describe a few considerations for the initial feasibility stage, more specifically, how to optimize quench conditions, how to tackle the carryover issue, and how to apply the pepsin specificity rule. Two sets of quench conditions are described depending on the presence of disulfide bonds to facilitate the quench condition optimization process. Four protocols are outlined to minimize carryover during the feasibility stage: (1) addition of a detergent to the quench buffer, (2) injection of a detergent or chaotrope to the protease column after each sample injection, (3) back-flushing of the trap column and the analytical column with a new plumbing configuration, and (4) use of PEEK (or PEEK coated) frits instead of stainless steel frits for the columns. The application of the pepsin specificity rule after peptide map generation and not before peptide map generation is suggested. The rule can be used not only to remove falsely identified peptides, but also to check the sample purity. A well-optimized HDX-MS feasibility stage makes subsequent HDX study stage smoother and the resulting HDX data more reliable. Graphical Abstract ᅟ.

Biomechanical Evaluation of the Use of PEEK versus PMMA Intervertebral Spacers in Lumbar Stabilization: the Influence of Bone Mineral Density and Vertebral Geometry

Introduction Degenerative spinal changes are often accompanied by osteoporosis in elderly patients. In these cases traditional interbody devices can strongly subside into the irregular deformed endplates and vertebrae during or after the surgical stabilization. To avoid implant subsidence, a new technique is developed where PMMA bone cement is applied as a custom-made interbody device providing better contact and more even load transfer along the vertebra-implant interface. The aim of this study was to compare the biomechanical properties of the two different spacer types. In this presentation, we focus on the connection between the bone mineral density and geometrical parameters of vertebrae and the compression failure of the spinal segment. Materials and Methods 22 monosegmental human cadaveric lumbar specimens were included in the analysis (Group “C” - cement: N = 12, Group “S” - spacer: N = 10). There were 8 steps to prepare the specimens: 1, isolation of a human cadaveric lumbar segment; 2, parallel embedding of cranial and caudal free endplates; 3, qCT scanning and vBMD measurement before applying interbody device; 4, introducing either a D-shaped PEEK spacer (Sanatmetal) or a custom made PMMA (Cemex) spacer as interbody device; 5, CT scanning after applying interbody device; 6, performing uniaxial compression tests (Instron 8872) and analyzing results (failure load and displacement, stiffness, elastic limit load and displacement); 7, CT scanning after the compression test; 8, finite element model was built to analyze the failure process using CT data. Results Comparison of initial geometrical data (vertebral cross sectional area, height, volume) and vBMD of “C” and “S” groups showed no significant difference. Failure load was similar in both groups. However, in the “S” group, there was a significant correlation between vBMD and failure load (R=0.73, p < 0.05), while such correlation was not observed (R = −0.04, p < 0.90) in the “C” group. The same association was observed for vertebral cross sectional areas (“S”: R=0.78, p < 0.01; “C”: R = −0.47, p < 0.20), vertebral height (“S”: R=0.94, p < 0.00; “C”: R = −0.27, p < 0,50), volume (“S”: R=0.85, p < 0.00; “C”: R = −0.49,p < 0.20) and failure load. Conclusion Analysis of mechanical test results showed that application of a PMMA cement spacer yields a significantly stiffer construct with smaller risk for subsidence compared with a PEEK spacer. However, load, that caused irreversible mechanical failure of the segments, were similar in both groups. In case of the PEEK spacer, the failure load does not depend on bone quality only, but on vertebral size parameters as well. In case of the PMMA cement spacer, such correlations were not observed. Finite element models showed completely different load transfer and failure process in the two groups. This difference is in line with our results above. In case of a relatively small vertebral size and poor bone quality, a prefabricated PEEK intervertebral cage may be associated with higher risk of mechanical failure then the use of PMMA as an interbody device.

An investigation into PEEK-on-PEEK as a bearing surface candidate for cervical total disc replacement

Total disc replacement (TDR) is a relatively new reconstructive non-fusion technology for the spine that aims to overcome some of the limitations of fusion technology. The first generation artificial discs were mainly based on well-known material combinations from total hip replacement. To evaluate the feasibility of PEEK-on-PEEK as a bearing surface material for use in cervical TDR. In vitro biotribological study including the assessment of different parameters, including the influence of radial clearance, axial load, and angular motion on the wear performance of a PEEK-on-PEEK bearing. PEEK-on-PEEK bearing couples with ball-and-socket articulation were prepared using standard production methods. Two groups of bearing couples, one with large radial clearances and the other with small radial clearances, were manufactured for testing. Wear tests were performed using a servo-hydraulic wear simulator that allowed controlled motions to be applied in three axes corresponding to flexion-extension, lateral bending, and axial rotation. In addition, a dynamic axial compressive load was applied to simulate the weight of the head. All tests were performed at 37°C (±2°C) in bovine calf serum with a 30 g/l protein concentration. In the first test series, the influence of the radial clearance on the wear behavior was evaluated using the load and motion parameters for cervical TDR as defined in the ISO standard 18192-1. Subsequent tests were performed to check if surface degradation was influenced by thermal effects. Finally, in a third series of tests, the effect of load and motion profiles on wear performance was investigated by applying increased loads and corresponding motion parameters for lumbar TDR as defined in the ISO standard 18192-1. The measured wear rates for a PEEK-on-PEEK bearing under cervical test conditions were considerably larger than those of similar testing using UHMWPE-on-CoCr and seemed to depend on initial radial clearances. The PEEK bearing surfaces exhibited severe surface degradation for large and small clearances, but the group with smaller clearances seemed to have less severe damage. Thermal effects were not found to play a role in the surface degradation, as the temperature near the bearing surface was measured and found to vary only a few degrees during testing. A change of the wear test parameters to simulate lumbar loading resulted in a considerable wear rate reduction as well as in the preservation of the bearing surfaces. It was found that a cervical TDR using a PEEK-on-PEEK bearing may be subjected to severe long-term degradation of the bearing surfaces. In this study, the use of PEEK as an articulation material for cervical TDR was found to be sensitive to loading conditions as well as to the initial clearance of the bearing surfaces. Despite the excellent properties of PEEK as an implant material, its use for articulating surfaces for cervical TDR must be critically reviewed.

Wear Performance of a Peek-on-Peek Bearing under Cervical Loading Conditions and at Different Test Frequencies

Introduction Due to its excellent mechanical and physico-chemical properties PEEK has been used for decades as a structural implant material in various non-articulating medical devices for the spine. It is self-evident that PEEK has been proposed as a possible bearing material for total disk replacement. This study aimed to assess the wear performance of an all PEEK ball-and-socket cervical TDR concept in an invitro wear simulation at different test frequencies. Materials and Methods Samples The articulation geometry of the test samples was based on a ball and socket design with an articulating radius of 7.5 mm. The articulation radii were rs = 7.64 mm (concave parts) and rb = 7.43 mm (convex parts). The radial clearance was 210 µm and the surface roughness of the wear samples Ra was approximately 0.16µm. Test set-up All PEEK samples were gamma irradiated and presoaked in demineralized water at ambient temperature for at least 2 weeks before testing. Wear tests were performed using an EndoLab servo-hydraulic wear simulator. The test set-up followed the protocol for cervical load profiles as defined in the standard ISO-18192-1. All tests were performed at 37°C in newborn calf serum with a protein content of 30 g/L. Tests were performed at 2 Hz for 10 million cycles and at 1 Hz for 3 million cycles with two samples per test frequency. The wear was determined gravimetrically after 0.5 million cycles, after 1 million cycles, and subsequently after each interval of 1 million cycles. The wear for the samples with same test frequency was pooled and the mean wear was calculated. To document the appearance of the bearing surfaces micrographs were taken at each measuring point. Results The wear data for 2 Hz test frequency showed in an initial phase between 0 and approximately 3 million cycles, a high wear rate of 5.09 mg/million cycles and in a second phase starting at 4 million cycles up to 10 million cycles, a markedly reduced wear rate of 1.44 mg/million cycles. At 1 Hz, a run in period with low wear was observed over the first million cycles, followed by a sudden wear rate increase. The wear rate at 1 Hz reached a value of 8.52 mg/million cycles, which was 67% larger compared to the initial wear rate at 2 Hz. Independent of the test frequency the images of the bearing surfaces indicated a dramatic wear damage with oval-shaped wear traces and severe scratching (see image/graph). Conclusion In literature Grupp et al,1 reported wear rates of 1.75 mg/million cycles for a similar set-up tested at 1 Hz. A second set of PEEK-on-PEEK wear simulator data for cervical loading but 2 Hz test frequency has been published by Brown et al2 who reported very low wear rates in the range of 0.4 mg/million cycles. The observed deterioration of the PEEK bearing surfaces (see image/graph) is in line with wear test results described by Grupp et al1 and Kraft et al3 but contradicts the self-matting behavior of a PEEK bearing as postulated by Brown et al2. The high wear rates for PEEK found in this study correlate with a severe deterioration of the bearing surfaces. These findings indicate that under loads and motion pattern relevant to cervical TDR, the use of PEEK as a bearing material might be subject to severe long-term damage of the bearing surfaces. Despite the excellent properties of PEEK as an implant material its use for articulating surfaces for cervical TDR must be critically reviewed. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest M. Kraft Employee of Synthes GmbH Grupp TM, Meisel HJ, Cotton JA, et al. Alternative bearing materials for intervertebral disk arthroplasty. Biomaterials 2010;31(3):523–531 Brown T, Bao Q, Hallab N. Biotribology assessment of NUNEC, a PEEK on PEEK cervical disk replacement according to ISO and ASTM recommendations. 9th Annual Meeting of the International Society for the Advancement of Spine Surgery 2009, abstract no 94 Kraft M, Koch D, Bushelow M; Evaluation of PEEK on PEEK as a new articulation concept for cervical total disk replacement - an in-vitro wear simulation study. European Spine Journal 2011;20:2050, abstract no P97

The use of PEEK nanorod arrays for the fabrication of nanoporous surfaces under high temperature: SiNx example

Large area silicon nitride (SiN(x)) nanoporous surfaces are fabricated using poly(ether-ether-ketone) (PEEK) nanorod arrays as a template. The procedure involves manipulation of nanoporous anodic aluminum oxide (AAO) templates in order to form an ordered array of PEEK nanopillars with high temperature resistant characteristics. In this context, self-ordered AAO templates are infiltrated with PEEK melts via the "precursor film" method. Once the melts have been crystallized in the porous structure of AAO, the basis alumina layer is removed, yielding an ordered array of PEEK nanopillars. The resulting structure is a high temperature and chemical resistant polymeric nanomold, which can be utilized in the synthesis of nanoporous materials under aggressive conditions. Such conditions are high temperatures (up to 320 °C), vacuum, or extreme pH. For example, SiN(x) nanopore arrays have been grown by plasma enhanced chemical vapor deposition at 300 °C, which can be of interest as mold for nanoimprint lithography, due to its hardness and low surface energy. The SiN(x) nanopore array portrays the same characteristics as the original AAO template: 120 nm diameter pores and an interpore distance of 430 nm. Furthermore, the aspect ratio of the SiN(x) nanopores can be tuned by selecting an AAO template with appropriate conditions. The use of PEEK as a nanotemplate extends the applicability of polymeric nanopatterns into a temperature regime up to now not accessible and opens up the simple fabrication of novel nanoporous inorganic surfaces.

The Difference of Material Wettability as Critical Factor in the Choice of a Tribological Prosthetic Coupling Without Debris Release

Today, in spite of the long experience acquired in the field of total hip replacements, prosthetic systems are still far from reproducing the natural system. One of the main causes of long term failure is the amount of wear debris produced by the tribological coupling between acetabolar cup and femoral head. The authors carried out experimental research in order to investigate the tribological coupling of various prosthetic biomaterials. Experimental tests were carried out with the pin-on-disc tribometer in dry, water and human serum as lubricant. This study sets new bases for the design of modern hip prostheses: 1. the wettability difference among the materials in tribological coupling, which is the necessary condition to promote efficient lubrication; 2. the use of Peek reinforced with long and unidirectional carbon fibres in the prosthetic field

Unusual Analyte Adsorption Effects on Inert Lc Components

Abstract The use of injector loops made of the inert polymer PEEKTM was studied for the analysis of non-steroidal anti-inflammatory drugs (NSAID) using microbore LC with peak compression. Surprisingly it was found that the use of PEEK not only failed to prevent adsorption of analyte in the loop but, in this instance, actually exacerbated the problem. The effect of loop overfill volume, competing NSAID in the sample solution and percentage organic component in the mobile phase on this phenomenon was investigated. Comparison was also made between PEEKTM and other materials used for injector loops.