Polyetheretherketone Material Research Articles

PEEK for Oral Applications: Recent Advances in Mechanical and Adhesive Properties.

Polyetheretherketone (PEEK) is a thermoplastic material widely used in engineering applications due to its good biomechanical properties and high temperature stability. Compared to traditional metal and ceramic dental materials, PEEK dental implants exhibit less stress shielding, thus better matching the mechanical properties of bone. As a promising medical material, PEEK can be used as implant abutments, removable and fixed prostheses, and maxillofacial prostheses. It can be blended with materials such as fibers and ceramics to improve its mechanical strength for better clinical dental applications. Compared to conventional pressed and CAD/CAM milling fabrication, 3D-printed PEEK exhibits excellent flexural and tensile strength and parameters such as printing temperature and speed can affect its mechanical properties. However, the bioinert nature of PEEK can make adhesive bonding difficult. The bond strength can be improved by roughening or introducing functional groups on the PEEK surface by sandblasting, acid etching, plasma treatment, laser treatment, and adhesive systems. This paper provides a comprehensive overview of the research progress on the mechanical properties of PEEK for dental applications in the context of specific applications, composites, and their preparation processes. In addition, the research on the adhesive properties of PEEK over the past few years is highlighted. Thus, this review aims to build a conceptual and practical toolkit for the study of the mechanical and adhesive properties of PEEK materials. More importantly, it provides a rationale and a general new basis for the application of PEEK in the dental field.

Stress analysis in implant, abutment, and peripheral bone with different restorative crown and abutment materials: A three-dimensional finite element analysis study

Background: Stresses on prosthetic crown directly influences the survival rate of implants hence it should be considered while selecting prosthetic material.The aim of the study is to evaluate stress analysis on implant, abutment and peripheral bone with change in different abutment and different crown materials by 3D finite element study.Materials and Methods: A numerical procedure based on finite element method was adopted to investigate the influence of different prosthetic materials and abutment materials on stress situation. Eight different three-dimensional (3D) models of a bone-level implant system and an abutment were created by using the standard tessellation language (STL) data of original implant components. Combinations included of abutment materials i.e., Titanium (Ti), Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polymer infilterated hybrid ceramic (TZI) along with different restoration materials Monolithic Zirconia (MZ) and lithium disilicate glass ceramic (IPS e-max). In each model, the implants were loaded obliquely (150 N). The stress distribution in the implant, Abutment and peripheral bone was evaluated through the von Mises stress analysis.Results: Higher stresses were found on neck of implants irrespective of abutment material and restorative material. Highest stress was found with PEEK material. The pattern of stress distribution in implant and peripheral bone was similar in all models.Conclusion: There is no difference in stresses with the change in restorative material but the change in abutment material has effect on stresses on implants.

Comparative analysis of stress and deformation distribution in implant supported telescopic systems made of different materials

Background/Aim. In implant prosthetics, there is an increasing use of materials that, with their mechanical characteristics, can alleviate the negative consequences of implant stress. The aim of this study was to conduct a comparative analysis of stress distribution and deformation of implant-supported telescopic systems and surrounding structures made of different materials using the finite element method. Methods. The 3D finite element models were prepared using the SolidWorks program (SolidWorks 2018, Concord, MA, USA). Two models of telescopic crowns with the characteristics of polyetherether-ketone (PEEK) polymer and cobalt-chromium (Co-Cr) alloy faceted with feldspar ceramics were used. The models were loaded with an axial force of 150 N in the region of the central fossa. The analysis of stress and strain distribution was per-formed by the finite element method in the Ansys software (ANSYS Workbench 16; Ansys Inc., Pittsburg, PA, USA). Results. Implant-supported telescopic crowns made of PEEK polymer significantly reduced stress in the implant and abutment neck area compared to the conventional Co-Cr crown veneered ceramic. At the level of bone structure, both models showed a concentration of stress at the level of the cortical bone, while the trabecular bone was significantly less exposed to stress. Under the same conditions, the degree of deformation of the secondary telescopic crown was more pronounced in models with PEEK polymer characteristics. Conclusion. Owing to their mechanical characteristics, PEEK polymers can be the materials of choice in the fabrication of superstructures on implants. Given that this in vitro study was accompanied by limitations, further research is needed to confirm the superior role of PEEK material in implant prosthetics.

Effects of various functional monomers' reaction on the surface characteristics and bonding performance of polyetheretherketone.

Polyetheretherketone (PEEK) is a new polymeric material that has received significant attention in dentistry because of its mechanical properties, biocompatibility, and aesthetics. However, the bonding performance of PEEK to other materials is not preferable. This study aimed to analyze the variations in the surface characteristics of PEEK under the chemical action of primers containing different functional monomers or polymers and to evaluate the bonding performance of PEEK and dental cement. Disk-shaped PEEK samples were prepared by dental milling, blasting with alumina oxide, and covering with primers containing functional monomers or polymers. The surface characteristics of the samples were analyzed by microscopy and spectroscopy. The shear bond strength (SBS) between PEEK and dental cement, with and without thermocycling, was tested using a universal testing machine. Finally, the data were statistically analyzed and compared. Functional monomers or polymers were successfully bonded to the surface of PEEK. This treatment significantly improved its hydrophilicity and surface free energy (P < 0.05). The primer containing pentaerythritol triacrylate had the highest SBS without thermocycling (13.89 MPa). Meanwhile, the primers containing urethane dimethacrylate (UDMA) and methyl methacrylate (MMA) (abbreviated as the HC group) showed the highest SBS and lowest reduction (25.51%) after thermocycling. Notably, all the testing groups achieved the ISO10477 standard of 5 MPa. After thermocycling, adhesive failure accounted for the largest proportion of failures in all the groups except the HC group. The chemical priming treatment can significantly improve the SBS of PEEK and dental cement. Moreover, a primer containing both UDMA and MMA can provide improved bonding for PEEK materials.

Study of the Thermomechanics of the Additive Manufacturing Process of Biocompatible Products Subject to the Viscoelastic Behavior of the Functional Material Polyetheretherketone

This study considers the problem of numerical modeling of the PEEK product’s 3D printing using the FDM technology. The aim of the study is to verify the adequacy of the use of a thermoviscoelastic model for numerical computations of the PEEK deposition process and to develop an algorithm for calculating this process. The Prony model is used to describe the thermoviscoelastic behavior of the material under study; the temperature-time shift is described by the Williams–Landel–Ferry function (WLF). To obtain the values of the material constants of the relaxation function, first, we used data from other authors; however, after their substitution into the numerical simulation, it was not possible to obtain results close to the full-scale experiment. Therefore, realized our own DMA experiment. The algorithm was developed and implemented in the ANSYS package to calculate non-stationary temperature fields and the stress–strain state of the structure during its layer-by-layer deposition. To solve these problems, the technology of “killing” and subsequent “aliving” of the PEEK material, implemented in the ANSYS package, is used. The numerical algorithm is verified with the results of an experiment on printing samples from PEEK. A good consistency of the calculated data with the experiment is shown.

Void Content Measurement of the 3D Printed PEEK Materials by X-Ray Micro Computed Tomography

Additive Manufacturing (AM) is revolutionizing the manufacturing industry as various AM technologies continue to mature and more AM-compatible materials are being developed. Polyether ether ketone (PEEK) is one of the promising materials at the forefront of this technological revolution as efforts to enhance its application as a 3D-printing material are continuously being pursued. In this study, the effect of printing parameters on the void content of 3D-printed PEEK was examined using a non-destructive method, X-ray micro computed tomography (X-ray micro-CT). Of the fused filament fabrication (FFF) parameters considered, higher nozzle temperature and printing speed were seen to promote an increase in void content while higher build plate temperature reduces it. Void content has a direct effect on the mechanical and other properties of the manufactured material and therefore provides a link between the printing parameters and the expected mechanical performance of these materials. This study also highlights the importance of choosing the right printing parameters to ensure the quality of the manufactured PEEK.

Comparison of marginal and internal adaptation of three-unit fixed dental prostheses made using CAD/CAM metal-free materials.

The aim of this study was to compare the marginal and internal adaptation of three-unit fixed dental prostheses (FDPs) fabricated from different metal-free materials using CAD/CAM methods. A total of 100 three-unit FDPs were produced from a cubic zirconia, a fiber-reinforced resin composite, a polyetheretherketone (PEEK), a polyetherketoneketone (PEKK), and a polymer composite material by the CAD/CAM method (n = 20 per material). The zirconia group was considered the control/reference material. Marginal and internal gap values of the produced FDPs were measured using the silicone replica method at ×40 magnification under a stereomicroscope. The obtained data were analyzed using one-way ANOVA and Tukey's HSD tests. The marginal and internal gap values for the cubic zirconia material were found to be statistically significantly lower than those seen for the PEEK, polymer composite, PEKK, and fiber-reinforced resin composite materials. While the marginal and internal adaptation of the cubic zirconia material was found to be better than the others, it should be noted that the marginal and internal gap values for all other materials tested were found to be within the clinically acceptable range.

Additively manufactured polyether ether ketone (PEEK) skull implant as an alternative to titanium mesh in cranioplasty.

173Cranioplasty is used for skull defects, involving lifting the scalp and restoring the contour of the skull with the original skull piece, titanium mesh, or solid biomaterial. Additive manufacturing (AM) technology, known as three-dimensional (3D) printing, is now utilized by medical professionals to develop customized replicas of tissues, organs and bones, offering a valid option with perfect anatomic fitting in the individual and skeletal reconstruction. Here, we report a case that underwent titanium mesh cranioplasty 15 years ago. The poor appearance of the titanium mesh weakened the left eyebrow arch and resulted in the formation of a sinus tract. Cranioplasty was performed using an additively manufactured polyether ether ketone (PEEK) skull implant. PEEK skull implants have been successfully implanted without any complications. To our knowledge, this is the first reported case of direct use of fused filament fabrication (FFF)-fabricated PEEK implant for cranial repair. The FFF-printed PEEK customized skull implant could possess simultaneously with adjustable material thickness and more complex structure, tunable mechanical properties, and low processing costs compared with traditional manufacturing processes. While meeting clinical needs, this production method is an appropriate alternative for promoting the use of PEEK materials in cranioplasty.

Biomechanical Tests on Long-Bone Elliptical Medullary-Canal Endoprostheses for Limb Salvage in Dogs.

Exo-endoprosthesis is a limb salvage procedure poorly described for animals, as only expensive metal devices have been used so far. Currently, additive manufacturing (AM) can make this type of implant affordable by exploring a wide new range of materials. However, safety factors should be considered and could be related to kinetic and kinematic studies of canine natural gaits. The suitability of a novel inner part of an exo-endoprosthesis manufactured by fuse deposition modeling (FDM) was assessed for long canine bones with an elliptical medullary canal. Polyether ether ketone (PEEK) was the material used as an alternative to metal for veterinary traumatology. Poisson's ratio of 3D-printed PEEK material and ex vivo mechanical tests of the customized endoprosthesis were performed for the evaluation. The customized endoprostheses had promising outcomes for the radii of 20 kg dogs. Quasistatic mechanical tests of bone-inserted endoprostheses-pure compression tests-reached a maximum force of 1045.0 ± 78.0 N. In fatigue tests, the samples reached 500,000 cycles without failure or detriment to their quasistatic results. These outcomes surpass the natural weight-bearing of dogs, even during a galloping pace. Furthermore, torque tests with different adhesives were performed to obtain reference data for future assessments comparing with natural dog movements.

PO33 Presentation Time: 10:30 AM: Testing the Usability of the Vaginal Speculum Tongue Made of Polyetheretherketone Material in Brachytherapy by Dosimetry Method

<h3>Purpose</h3> In the tandem + ovoid brachytherapy application, during the metallic speculum removing process after the vaginal packaging process, the positions of the sponges may change due to the spoon-shaped structure of the speculum, and this situation may cause not desired efficiency from the packaging process. In this project, we aimed to 3D printing of vaginal speculum tongues from polyetheretherketone (PEEK) material and make the dosimetric evaluation to assess usability during packing in gynecologic brachytherapy. <h3>Materials and Methods</h3> In this study, we designed a modular structure in which the upper and lower tongue can be easily separated from the handle similarly to the metallic vaginal speculum we use in our routine practice with no requirement to remove the speculum tongues from the patient after packaging. The tongues of the designed speculum were produced with PEEK material with a layer thickness of 200 microns using a 3D printer (Intamsys Technology Co. Ltd., Shanghai, China). To evaluate the radiation permeability of the produced speculum tongues, a phantom containing water was designed to perform dosimetric studies and 2 different dosimetric methods were used such as the treatment planning system (TPS) and Radiochromic Film Dosimeter system (Gafchromic: EBT3). TG43 and ACUROS BV algorithms are used as TPS. Prescribed dose (3 Gy) at the surface of phantom (side with the speculum) was calculated for a single source Dwell position in TPS using with ACUROS BV algorithm. The irradiation time was 631.1 seconds for both algorithms. The activity of the radioactive source was 11,086 Ci. The measured values that were obtained from the same points with different techniques were recorded and relations with each other were evaluated by using the Pearson Correlation test. In each measurement method, dose values were recorded in 4 different directions such as right (with no speculum), left (with speculum), up, and down. Dose-distance graphs were created for each direction from these values, and no break in the curve was detected on the side of the speculum tongue in phantom. This work was supported by Eskisehir Osmangazi University Scientific Research Projects Unit as project number TSA-2021-2143. <h3>Results</h3> The measurement values obtained from two different TPS algorithms and the film dosimetry method are given in Figure 1, and no significant difference was found in the statistical evaluation. The values obtained by using different methods show parallelism with each other, and no breakage was detected due to the speculum tongue. <h3>Conclusions</h3> In conclusion, all values obtained from TPS and radiochromic film dosimetry were parallel to each other. When the dose values at the same points and dose-distributions were evaluated, we concluded the speculum tongues we produced from PEEK did not have any negative effect on the dose distribution. However, this proposition needs to be supported by making more measurements with different dosimetry methods.

An experimental investigation on the tensile properties of PEEK-PEI sandwich structures prepared via fused filament fabrication

High-temperature-resistant thermoplastics, e.g., Polyetheretherketone (PEEK) and Polyetherimide (PEI), exhibit much more superior material properties than conventional plastics. They are recently becoming favorable feedstock materials in Fused Filament Fabrication (FFF) 3D printing applications, which yields a low-cost and high-efficient approach providing complex parts and tooling. This paper fabricates the PEEK-PEI combined sandwich structures by properly alternating the fed material during FFF processes, aiming to combine the benefits of both materials. This is considered one of the first few attempts to prepare high-performance thermoplastics-based sandwich samples via the FFF method. The specimens are designed as three-layer and five-layer sandwiches (i.e., each “layer” contain a unique material). In addition, the printed samples are post-processed via a thermal annealing treatment. Experimental results show that the sandwich specimens exhibit higher surface quality than independently printed PEEK materials. The PEI material can be printed in 100% infill density in sandwich structures, while it can be rarely printed independently with infill densities exceeding 40%. Annealing may not enhance the mechanical properties of sandwich specimens while stabilizing their mechanical performances. Under the same PEEK/PEI volumetric ratio (i.e., 1:1), increasing the number of alternating stack layers improves the tensile strength of the sandwich specimens by up to 17%. The sandwich printing method is also cost-effective, such that the five-layer sandwich specimen provides competitive tensile performance as compared to the virgin PEEK material. At the same time, its cost is only ∼60% of all-PEEK specimens.

Finite element analysis of the biomechanical effects of titanium and Cfr-peek additively manufactured subperiosteal jaw implant (AMSJI) on maxilla

The aim of this study is to examine the stresses that will occur under occlusal forces on the cortical bone, spongious bone and the subperiosteal implant systems made of Titanium and%60 Carbon fiber reinforced Polyether ether ketone (PEEK) material. Two different models of subperiosteal implant systems on maxilla made of Titanium and %60 Carbon fiber reinforced Polyether ether ketone (PEEK) material. As a result of vertical and oblique forces, the stress values and distributions on the subperiosteal implant systems and bone were examined. After applying the three different force protocols, von Mises stress, Maximum principal stress and Minimum principal stress values and distribution on the subperiosteal implant body, fixation screws, cortical and spongious bone were analyzed by finite element analysis. In all scenarios, the von Mises values ​​on the Titanium subperiosteal implant system were found to be approximately twice on the 60% carbon fiber reinforced PEEK subperiosteal implant system plates. Subperiosteal implants produced from titanium and carbon fiber reinforced PEEK material exhibited similar stress values on cortical and spongious bone. According to the results of this study, 60% Carbon fiber reinforced PEEK material can be considered as an alternative material to titanium since it exhibits similar biomechanical behavior with titanium subperiosteal implants on cortical and spongious bone. In order to be routinely used as dental subperiosteal implant material, it should be supported by long-term in vivo studies.

In vitro physicochemical and biological properties of titanium alloy, zirconia, polyetheretherketone, and carbon fiber-reinforced polyetheretherketone

Implant repair is a common means to restore the normal function of the hard tissues (bone or teeth). At present, the commonly and potentially used implant materials include titanium alloy (Ti), zirconia (Zr), polyetheretherketone (PEEK), and 30% carbon fiber reinforced PEEK (CFR-PEEK). This study compares their physicochemical and biological properties, including surface morphology, contact angle, nano hardness, elastic modulus, and the impact on the proliferation and osteogenic differentiation of bone marrow mesenchyml stem cell. Additionally, the differences in bacteria adhesion rates among materials were compared. CFR-PEEK had the highest contact angle, followed by PEEK, Zr, and Ti. Zr had the highest nano hardness and modulus of elasticity, followed by Ti, CRF-PEEK, and PEEK. There was no statistically significant difference in cytotoxicity among materials based on the liquid extract test. However, the relative cell proliferation rate on the surface of CFR-PEEK was slightly lower than that of Ti and Zr. Moreover, alkaline phosphatase activity, extracellular matrix mineralization, and osteogenic gene expression with the Ti and Zr materials were higher than with the PEEK and CFR-PEEK materials at Day 7, and Zr showed the highest osteogenic gene expression level among materials at Day 14. Ti had the greatest number of bacterial colonies that adhered to it, followed by Zr, CFR-PEEK, and PEEK. While the mechanical properties of PEEK and CFR-PEEK were closer to bone tissue and their anti-adhesion effect against bacteria was better than those of Ti and Zr, modification methods are needed to improve the osteogenic properties of these biopolymers.

Dual-functional polyetheretherketone surface with programmed sequential drug release coating

The poor bacteriostasis and osseointegration properties of bioinert polyetheretherketone (PEEK) hinder its clinical application. This work reports a simple and versatile strategy for fabricating dual-functional coating with programmed sequential drug release properties on porous PEEK surfaces. The dual-drug-loaded composite coating composed of drug-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles and drug-loaded polyvinyl alcohol (PVA) gel can be immobilized on the surface of sulfonated PEEK by a cyclic freeze-thaw method. Based on the swelling of PVA and the slow degradation of PLGA, the composite coating can realize rapid release of antibacterial drugs and sustained release of osteogenic drugs. The in vitro antibacterial evaluations show that the porous PEEK modified with drug-loaded composite gel coating exhibits an early effective fight against Staphylococcus aureus (S.aureus). The results of in vitro cell experiments show that the PEEK materials modified by the composite gel coating can well support the normal growth, adhesion and proliferation of cells. In addition, the PEEK material coated with the drug-loaded composite gel is found to have positive effects on the osteogenic differentiation of cells in detections of alkaline phosphatase (ALP) activity of cells and the amount of calcium deposition on the surface of the material. The results demonstrate that the proposed porous PEEK modified with dual-drug-loaded composite gel coating simultaneously exhibits excellent osseointegration and exerts early effective antibacterial activity. This dual-functional PEEK material has great application potential in clinical bone tissue repair.

Finite Element Study of PEEK Materials Applied in Post-Retained Restorations.

Background: This study aimed to investigate the biomechanical behaviors of polyether ether ketone (PEEK) and traditional materials (titanium and fiber) when used to restore tooth defects in the form of prefabricated post or customized post via computational modelling. Methods: First, the prototype of natural tooth, and the prototypes of prefabricated post and customized post were established, respectively, whilst the residual root was restored with dentin ferrule using reverse engineering methods. Then, the stress and strain of CFR-PEEK (PEEK reinforced by 30% carbon fiber) and pure PEEK (PEEK without any reprocessing) post were compared with those made in traditional materials using the three-dimensional finite element method. Results: From the stress point of view, compared with metal and fiber posts, CFR-PEEK and pure PEEK prefabricated post both demonstrated reduced post-core interface stress, post stress, post-root cement stress and root cement stress; moreover, CFR-PEEK and pure PEEK customized post demonstrated reduced post stress, post-root cement stress and root cement stress, while the strain of CFR-PEEK post was the closest to that of dentin. Conclusions: Compared with the traditional posts, both the CFR-PEEK and pure PEEK posts could reduce the risk of debonding and vertical root fracture, whether they were used as prefabricated posts or customized posts, but the biomechanical behavior of carbon fiber-reinforced CFR-PEEK restorations was the closest to dentin, no matter if they were used as prefabricated post or customized post. Therefore, the CFR-PEEK post could be more suitable to restore massive tooth defects. Pure PEEK needs filler reinforcement to be used for post-retained restoration.

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

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

Mussel-inspired dopamine-CuII coated polyetheretherketone surface with direct and immunomodulatory effect to facilitate osteogenesis, angiogenesis, and antibacterial ability

Implant-associated infection (IAI) and insufficient implant osseointegration are two primary concerns of implant failure. Polyetheretherketone (PEEK), though widely used in orthopedic implants, has been limited in clinical applications by its poor osteogenic activity, inferior antibacterial ability, and improper immunological reactions. In this study, copper (Cu), a multi-functional bioactive ion, is incorporated into the polydopamine (PDA) coating on PEEK surfaces using a metal-catecholamine assembling strategy. This DA-CuII coating induces a spatial distribution of Cu, exerting biological functions simultaneously through passive contact and active release of Cu. DA-CuII coated PEEK surfaces exhibit not only superior abilities of osteogenesis, angiogenesis, and antibiosis but also possess immunomodulatory effects to enhance macrophages-mediated osteogenesis and antibacterial activity. Moreover, the DA-CuII coated PEEK induces a mild and necessary inflammatory response, exhibiting excellent antibacterial ability and superior osseointegration. Our findings suggest that DA-CuII coated PEEK has excellent potential for orthopedic implants and provides new insight into novel modification strategies of PEEK materials.

Would augmentation genioplasty using patient-specific PEEK (Polyether Ether Ketone) implant meet patient’s expectations?

Introduction: Patient-specific implants become very valuable in restoring facial contours, including the chin area. Evaluation of patient satisfaction with the esthetic results should be a primary concern. Aim of study: To evaluate the success of augmentation genioplasty using patient-specific PEEK (Polyether Ether Ketone) implant in meeting patient’s expectations. Methods: Seven patients were enrolled in this study. They were all having deficient chin that was managed by augmentation genioplasty using patient-specific PEEK implant. Preoperative clinical evaluation was performed for all patients. With the help of MIMICS and 3-MATIC soft wares, diagnosis, virtual planning and final implant design were done. Finally, STL file was sent for milling using PEEK material. Under GA, PSI was inserted through an intra-oral vestibular approach and fixed to the underlying bone using mini-screws. Patient expectations were evaluated by Face-Q questionnaire. Result: The study was conducted on 7 cases, 3(42.9%) of which were males and 4(57.1%) were females. The mean age of the cases was (22.00±1.29) years. All patients showed high degree of contentment with the procedure. Conclusions: Patient-specific PEEK implant can be used for chin augmentation with good esthetic results close to that of patients’ expectations.

Fatigue behavior of removable partial denture cast and laser-sintered cobalt-chromium (CoCr) and polyetheretherketone (PEEK) clasp materials.

To investigate the fatigue behavior of cast and laser-sintered cobalt-chromium (CoCr) and polyetheretherketone (PEEK) material for a removable partial denture (RPD) clasps. Dumbbell-shaped specimens were digitally designed with the center part of the dumbbell being a half-round shape at the cross-sectional dimension of 1.25 mm to simulate a typical clasp design and dimensions. A fatigue machine with an offset axis rotation system simulated a typical undercut depth of 0.25, 0.50, and 0.75 mm. Each group was subjected to 30,000 fatigue cycles (simulating 21 years) or till specimen failure. Before testing, the stress value at each undercut depth for each specimen was established in a universal testing machine and SN curves were plotted for each group. Data were statistically analyzed using Kruskal-Wallis and post hoc tests. The fractured surfaces were analyzed using SEM. The average fatigue cycles with 0.25, 0.50, and 0.75 mm undercuts were 27,155 ± 6277, 9298 ± 4033, 5642 ± 8785 for cast CoCr and 26,765 ± 6150, 11,318 ± 7931, 2861 ± 4803, for laser-sintered CoCr, respectively. Apart from three specimens, the PEEK groups did not fail during the simulation period. Clasps with 0.25 mm deflection showed significantly higher fatigue resistance than other groups (p < .001). There was no significant difference in fatigue behavior between the cast and laser-sintered CoCr. Microporosities at the fractured site along with irregular crack propagation were observed for cast and laser-sintered CoCr specimens. Fatigue-induced broken polymer crosslinking chains were observed in PEEK specimens. PEEK material exhibited the highest fatigue resistance and significantly lower deflection resistance. Cast and laser-sintered CoCr showed similar fatigue resistance and behavior.

Vertical marginal gap evaluation of PEEK and Zirconia crowns using extra-oral scanner and CAD/CAM systems (An Invitro study).

Background and objective: Selecting a material with lower marginal gap is the key factor for a successful dental prosthesis. With less marginal gap of the crown the aggregation of bacterial plaque at the gingival margins, that result in periodontal diseases and secondary caries could be limited. Methods: A mandibular right first molar of a sound tooth was prepared for the reference model according to the tooth preparations guideline with a heavy chamfer finishing line for full zirconia and Polyetheretherketone (PEEK) coverage. Digital impression technique with extraoral scanner was used for scanning and taking impression of the reference model, ten crowns in each group were designed and milled using CAD/CAM systems. The vertical marginal gap between the crown's margin and the finishing line was measured for each crown on the reference model with the aid of a stereomicroscope in 160x. Results: The average (mean) for the marginal gap of proximal, buccal and lingual surfaces of both PEEK, and zirconia materials were: 409.097 μm, 112.869 μm, 198.563 μm, for PEEK and, 105.085 μm, 27.659 μm, 45.135 μm for zirconia respectively. Statistical analysis using t-test for two independent samples revealed that PEEK material showed a significantly higher marginal gap than z. irconia material. Conclusion: PEEK crowns had a higher marginal gap than clinically acceptable limit, while zirconia crowns exhibited much lower measurements.