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The aim of this study was to investigate the bond strength between PEEK/PEKK and composite resins after various laser treatments and to compare the effectiveness of lasers on these polymers. 130 disc-shaped PEEK and PEKK blocks were obtained (10 mm diameter-4 mm height). One sample from each group (10 in total) was selected for scanning electron microscopy (SEM) analysis. The samples were randomly divided into 5 different surface treatment groups for each material (PEEK and PEKK): Er: YAG laser, Nd: YAG laser, diode laser, femtosecond laser and control (no surface treatment) (n = 12). Baseline and post-treatment surface roughness measurements were performed using a profilometer. The composite resin was bonded and SBS was measured. Comparisons among the groups were conducted via Kruskal–Wallis, one-way ANOVA; Tukey and Dunn tests were used as a post hoc test (p ≤ 0.05). All lasers significantly increased the roughness values of the PEEK and PEKK samples. In terms of shear bond strength; the Er: YAG and femtosecond laser groups had the highest values and the Nd: YAG, diode and control groups had the lowest values of the PEEK samples (p ≤ 0.05). The control group had the highest bond strength values and the femtosecond group had the lowest values for PEKK samples (p ≤ 0.05). All laser treatments increased the surface roughness of the PEEK and PEKK. Lasers increased the bond strength of PEEK to the veneering composite resin and decreased the bond strength values of PEKK. This shows that lasers behave differently in PEEK and PEKK materials. [ABSTRACT FROM AUTHOR]

New materials have emerged in the dental field to replace the cobalt-chrome (CoCr) alloy used for the metal frameworks in removable partial denture (RPD) such as Titanium (Ti) and PolyEtherEtherKetone (PEEK). However, few studies have demonstrated their mechanical and biological performance. The purpose of this systematic review was to compare the performance of Ti and PEEK in RPD using CoCr metal framework as a reference. This review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three data bases were analyzed, including PubMed/MEDLINE, Embase and Web of Science before March 2024. Only studies assessing the mechanical and/or biological properties of RPD in Ti, PEEK and CoCr were included. The quality of the studies was assessed by using the software Rayyan. The risks of bias were assessed with the methodological index for nonrandomized studies (MINORS). The mechanical (retention force, fatigue life, deformation strength, machinability, rigidity, porosity and surface roughness) and biological (plaque indices, ion release and biocompatibility) aspects were assessed. Among 138 articles identified, only 18 studies were included in this review. Majority had a low to moderate risk of bias. Retention forces and fatigue were significantly lower for Ti and PEEK than for CoCr, and the same was true for Ti rigidity. PEEK showed less deformation. Both materials were suitable for machining. In terms of biological properties, both materials showed adequate biocompatibility for clinical use. Ti and PEEK seems to be promising as alternative materials to CoCr frameworks for RPD, in terms of both their mechanical and biological performance. However, additional studies are needed to better understand their clinical and long-term limitations to enable the best-informed clinical choice for the patients and the professionals. [ABSTRACT FROM AUTHOR]

BACKGROUND: Polyetheretherketone is a special plastic polymer with good mechanical properties, biocompatibility, and chemical stability, which can be added with different fillers to form new composite materials and has potential clinical application value in post core repair. OBJECTIVE: To review the properties of polyetheretherketone and its composite materials, as well as the clinical application progress in post core repair. METHODS: CNKI database was searched using the Chinese search terms “polyetheretherketone, post core repair, metal post, fiber post, zirconia post”. PubMed database was searched using English search terms “PEEK, polyetheretherketone post, post core repair, dental dowels”. Search time ranged from January 2019 to October 2023. By reading literature titles, abstracts, and selecting the entire text, the inclusion and exclusion criteria were used to screen and finally include 71 articles for review. RESULTS AND CONCLUSION: Polyetheretherketone is a high-performance thermoplastic polymer. Experimental studies have proven that polyetheretherketone and its composites have advantages in mechanical properties, biocompatibility, aging resistance, chemical stability, adhesive properties, etc., and have promising application prospects in the field of post core repair. The clinical application of polyetheretherketone and its composite materials as post core restorations is limited to anterior teeth and premolars, but they have achieved satisfactory restoration results. Polyetheretherketone and its composite materials are new materials in post core repair, and there are still many problems to be solved, such as whether the 3D printing equipment and printing process will affect the mechanical properties of the materials; short observation time for clinical repair effects, lack of long-term research validation. There is a lack of case reports on the use of polyetheretherketone and its composite materials as post and core materials for repairing molars, and further research is needed to continuously improve related studies. [ABSTRACT FROM AUTHOR]

Recent studies have indicated that the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is an ideal therapeutic target for osteoporosis because it affects the differentiation of osteoblasts and osteoclasts. RNA sequencing utilizing multifunctional graphene oxide (GO) nanosheets revealed a correlation between GO nanomaterials and the NLRP3 inflammasome, as well as osteogenic genes in macrophages. This study aimed to construct a bone microenvironment-responsive multifunctional two-dimensional GO coating on the surface of microporous sulfonated polyetheretherketone (SPEEK) via polydopamine modification (SPEEK@PDA-GO). In vitro analysis showed that the SPEEK@PDA-GO implants weakened the STAT3-mediated NLRP3/caspase-1/IL-1β signaling pathway in macrophages and subsequently prevented the formation of an extracellular inflammatory microenvironment, which is crucial for osteoclastogenesis. SPEEK@PDA-GO displayed significantly higher expression of M2 macrophage markers and osteogenic genes, indicating that the multifunctional GO nanosheets could facilitate bone regeneration via their immunomodulatory properties. The ability of SPEEK@PDA-GO to stimulate new bone formation and block bone loss caused by estrogen loss due to ovariectomy was also analyzed. The findings of this study offer valuable information on the possible involvement of the NLRP3 inflammasome in the interaction between the immune system and bone health in patients with osteoporosis. [Display omitted] • We developed SPEEK@PDA-GO to regulate immune-mediated bone homeostasis. • SPEEK@PDA-GO created a desirable osteoimmunomodulatory microenvironment. • SPEEK@PDA-GO inhibited the STAT3-mediated NLRP3/caspase-1/IL-1β axis in macrophages. • GO nanosheets restored the balance between osteogenesis and osteoclastogenesis. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to compare the fracture strength and fracture modes of post-cores produced with CAD-CAM from modified polyetheretherketone (PEEK) materials with other custom-produced post-cores. Methods: Sixty human mandibular first premolars with equal root sizes were used. The teeth were divided into six groups (n = 10), and root canal treatment was performed. The teeth were separated from the roots over 2 mm from the cemento-enamel junction. As a result of the decoronation process, a 1 mm wide shoulder line was obtained for all teeth. For the fracture strength test, 10 mm deep post spaces were created on the teeth with a 1.6 mm diameter driller. Post-core groups consisted: everStick® glass fiber post-core (Group GF), zirconia post-core (Group Z), metal (Cr-Co) post-core (Group M), PEEK post-core without filler (Group UP), PEEK post-core with 20% TiO2 Filler (Group TP), and post-core with 20% ceramic filler (Group CP). Following the application of posts to post spaces, copings were created and cemented on the samples. With the universal tester, a force was applied to the long axis of the tooth with a slope of 135°. The mean fracture strength (N) between the groups was statistically evaluated using one-way ANOVA, and pairwise mean differences were detected using post hoc Tukey's HSD test among the groups. Results: According to the results of the statistical analysis, a significant difference was found between the groups in terms of mean fracture resistance (p < 0.05). Group Z (409.34 ± 45.72) was significantly higher than Group UP (286.64 ± 37.79), CP (298.00 ± 72.30), and TP (280.08 ± 67.83). Group M (376.17 ± 73.28) was significantly higher than Group UP (286.64 ± 37.79) and Group TP (280.08 ± 67.83). There were no statistically significant differences between the means of the other groups (p > 0.05). Among all the groups, Group Z exhibited a higher prevalence of repairable failure modes, while the rest of the groups predominantly experienced irreparable failure modes. Conclusion: In our study, zirconia and metal post-core samples showed higher average fracture strength values than PEEK post-cores groups. Repairable failure modes were more common in the zirconia post-cores, whereas the opposite was observed in the other groups. Further experimental and clinical trial studies are needed before PEEK materials can be used as post materials in the clinic. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) is gaining recognition as a highly promising polymer for orthopedic implants, attributed to its exceptional biocompatibility, ease of processing, and radiation resistance. However, its long‐term in vivo application faces challenges, primarily due to suboptimal osseointegration from postimplantation inflammation and immune reactions. Consequently, biofunctionalization of PEEK implant surfaces emerges as a strategic approach to enhance osseointegration and increase the overall success rates of these implants. In our research, we engineered a multifaceted PEEK implant through the in situ integration of chitosan‐coated zinc‐doped bioactive glass nanoparticles (Zn‐BGNs). This novel fabrication imbues the implant with immunomodulatory capabilities while bolstering its osseointegration potential. The biofunctionalized PEEK composite elicited several advantageous responses; it facilitated M2 macrophage polarization, curtailed the production of inflammatory mediators, and augmented the osteogenic differentiation of bone marrow mesenchymal stem cells. The experimental findings underscore the vital and intricate role of biofunctionalized PEEK implants in preserving normal bone immunity and metabolism. This study posits that utilizing chitosan‐BGNs represents a direct and effective method for creating multifunctional implants. These implants are designed to facilitate biomineralization and immunomodulation, making them especially apt for orthopedic applications. [ABSTRACT FROM AUTHOR]

The biomaterials applicable in dental implantology, or implantology generally, are subject to specific requirements, namely biocompatibility, osseointegration, resistance to fracture/ oxidative degradation/ long-term compressive stress/ hydrolisis in boiling water, suitable morphology, suitable physical properties (including mechanical properties), aesthetics, etc. When selecting a suitable material for dental implants, it is also necessary to consider the patient's current health condition and possible complications when placing titanium implants and alloys. If there is a risk of an allergic reaction or hypersensitivity to any of the components of the metal prosthesis, the placement of a semicrystalline thermoplastic implant - called polyetheretherketone, abbreviated PEEK - is a possible option. Such a wide range of stiffness means that PEEK formulations can be produced with modulus values similar to cortical bone. PEEK is classified as a High Performance Polymer of polymer pyramide (such as Polysulfones polybutylene terephthalate). PEEK can be applied for dental abutment and dental body. This article summarises basic information on the structure and properties of PEEK polymer, advantages/ disadvantages (compared to metal - titanium restorations), application and general information from the examined field. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Infection and poor tissue repair are the key causes of percutaneous implantation failure. However, there is a lack of effective strategies to cope with due to its high requirements of sterilization, soft tissue healing, and osseointegration. In this work, l-arginine (L-Arg) was loaded onto a sulfonated polyetheretherketone (PEEK) surface to solve this issue. Under the infection condition, nitric oxide (NO) and reactive oxygen species (ROS) are produced through catalyzing L-Arg by inducible nitric oxide synthase (iNOS) and thus play a role in bacteria sterilization. Under the tissue repair condition, L-Arg is catalyzed to ornithine by Arginase-1 (Arg-1), which promotes the proliferation and collagen secretion of L929 and rBMSCs. Notably, L-Arg loading samples could polarize macrophages to M1 and M2 in infection and tissue repair conditions, respectively. The results in vivo show that the L-Arg loading samples could enhance infected soft tissue sealing and bone regeneration. In summary, L-Arg loading sulfonated PEEK could polarize macrophage through metabolic reprogramming, providing multi-functions of antibacterial abilities, soft tissue repair, and bone regeneration, which gives a new idea to design percutaneous implantation materials.

Purpose: To demonstrate the likelihood of the polyetheretherketone (PEEK), zirconia (ZrO2), and titanium (Ti) disks to support proliferation and hemidesmosome formation of gingival cells. Materials and Methods: Water contact angle was performed on each material, and surface roughness (Ra) was measured. Scanning electron microscopy and x-ray photoelectron spectroscopy were used. Later, oral keratinocyte cells were cultured on disks, and metabolic activity and expression of hemidesmosome markers, integrin α6 and β4, in relation to the biomaterial disks at 1, 3, and 5 days of cell culture were quantified. Tissue culture polystyrene was used as the control. Statistical analysis was performed with analysis of variance (ANOVA) with Tukey post hoc comparison test. A P value of < .05 was considered statistically significant. Results: The water contact angle ranged from 70.2 degrees (Ti) to a maximum of hydrophobicity of 93.3 degrees (PEEK). Ra was highest on ZrO2, followed by PEEK. Ti showed the most keratinocyte metabolic activity at 1, 3, and 5 culture periods. Contrarily, ZrO2 and PEEK disks had lower keratinocyte metabolic activity at all observation times, with no statistical differences between both groups. Integrin α6 and β4 expression was highest on TCPS and ZrO2 compared to Ti and PEEK. Conclusion: Keratinocytes proliferated faster on Ti than on ZrO2 and PEEK substrates, and expression of hemidesmosome formation markers, integrin α6 and β4, were higher on ZrO2 than either Ti or PEEK. [ABSTRACT FROM AUTHOR]

Abstract Background Multi-rooted teeth with extensive dental defects often face challenges in stability and biomechanical failure. High-performance polymer PEEK materials, with properties closer to dentin, show promise in reducing stress concentration and preserving tooth structure. This report aimed to explore the use of a highly retentive polyetheretherketone (PEEK) for manufacturing custom-made split post and core for the restoration of grossly destroyed endodontically treated molars. Clinical considerations A 40-year-old female patient presented with complaints of loss of tooth substance in the posterior mandibular tooth. This case involved the digital design and fabrication of PEEK split post and core to restore multirooted molar with insufficient dental tissue remnants. The restorations were evaluated over a 3-year follow-up using the World Federation criteria (FDI). The restoration was clinically evaluated through intraoral examination, radiographic assessment, and subjective patient satisfaction, and was deemed clinically good according to FDI criteria. Conclusion The outstanding mechanical properties of PEEK, coupled with the structure of the split post, provide an effective treatment option for weakened multirooted teeth. Simultaneously, the restoration configuration effectively addressed the challenge of varying postinsertion directions, and the interlocking mechanism between the primary and auxiliary posts enhanced the stability of the post and core.

Aim: Synthetic inorganic materials are commonly used as reinforcing agents in polyetheretherketone (PEEK) composite, whereas natural organic plant-based reinforcing agents are negligible. Surface hardness, roughness, and wettability are indicative factors of osseointegration behavior to be used as an implant material. This study evaluated micro surface hardness (MSH), nano surface hardness (NSH), surface roughness (SR), and contact angle (CA) of PEEK-Azadirachta indica reinforced at 10 wt%, 20 wt%, and 30 wt%. Settings and Design: This was an in vitro study. Materials and Methods: Neem (A. indica) leaf nanoparticles were prepared and reinforced with PEEK powder at 10%, 20%, and 30% weight ratios by injection molding. Sixty specimens underwent the microhardness and CA testing using a digital microhardness tester, and CA goniometer, respectively, and later nanoindentation test to analyze the nanohardness and SR. Statistical Analysis Used: A one-way ANOVA test with a 95% confidence interval for MSH and NSH, SR, and CA was performed on the samples. A post hoc Bonferroni test was conducted (α = 0.05) to compare the groups. Results: There was a significant increase in nanohardness (P = 0.000) with zero difference in microhardness (P = 0.514). The addition of 10 wt%, 20 wt%, and 30 wt% nanoparticles increased the SR value of the pure PEEK from 273.19 nm to 284.10 (3.99%), 296.91 (8.68%), and 287.54 (5.24%), respectively. In the analysis of the CA, CA 20% shows the lowest angle (63.69) with the highest for control specimens (82.39). There is an increase in the PEEK composite SR with a decrease in CA. Conclusions: The addition of plant-derived nanoparticles into the PEEK matrix has a significant impact on the hardness and hydrophobicity enhancing cell growth and osteoblastic differentiation during osseointegration of dental implants.

Aim: This study investigates the interaction of zirconia and polyetheretherketone (PEEK) with indirect composite in fixed dental prostheses. This investigation aimed to assess the shear bond strength (SBS) and color stability of zirconia and PEEK before and after aging, addressing critical concerns in dental restorative applications. Settings and Design: The current in vitro study used 96 samples, 48 of which were divided into two groups, zirconia and PEEK, before and after thermocycling. A dual-axis chewing simulator was used for thermocycling. SBS was measured using a universal testing machine, and color stability was checked using a reflective spectrophotometer. Materials and Methods: Ninety-six samples were categorized into zirconia and PEEK groups, each with subgroups undergoing thermocycling. Samples were prepared using computer-aided design/computer-aided manufacturing milling and veneered with composite resin. Thermocycling involved 10,000 cycles, simulating stress levels equivalent to approximately 1 year of clinical use. SBS was assessed using standardized tests. Stereomicroscopic analysis was performed to evaluate the type of failure. Color stability of the core materials with indirect composite was done using a spectrophotometer before and after aging. Statistical Analysis Used: Statistical analysis included paired t-tests and independent t-tests in SPSS software. Results: The results revealed that SBS values for composite on PEEK decreased from 13.86 ± 0.164 MPa before thermocycling to 13.46 ± 0.185 MPa after thermocycling, with a significant difference (P < 0.005). However, both pre- and postthermocycling values for PEEK were higher than zirconia. The t-test confirmed the lower bond strength of composite to zirconia, with a noteworthy improvement after aging. Stereomicroscopic images revealed adhesive failure for the zirconia group and mixed (adhesive and cohesive) failure for the PEEK group. ΔE values were 3.21 ± 0.127 and 2.93 ± 0.142 for zirconia and PEEK groups, respectively (P < 0.005). Conclusion: Within the limitations of this study, it can be deduced that PEEK is a feasible substitute for zirconia when used in conjunction with indirect composite for the fabrication of dental prostheses.

Abstract Background Preservation of the remaining structures while maintaining an esthetic appearance is a major objective in removable partial prosthodontics. So, the aim of the current study was to compare the stresses induced on the supporting structures by two digitally produced esthetic core materials; Zirconia and Polyetheretherketone when used as an extracoronal attachment in distal extension removable partial dentures using strain gauge analysis. Methods A mandibular Kennedy class II stone cast with the necessary abutments’ preparations was scanned. The mandibular left canine and first premolar teeth were virtually removed. An acrylic mandibular left canine and first premolar teeth were prepared with heavy chamfer finish line and scanned. Virtual superimposition of the acrylic teeth in their corresponding positions was done. Two strain gauge slots were designed: distal to the terminal abutment and in the residual ridge. Two models and two sets of scanned teeth were digitally printed. The printed teeth were then placed in their corresponding sockets in each model and scanned. The attachment design was selected from the software library and milled out of Zirconia in the model ZR and Polyetheretherketone in the model PE. Five removable partial dentures were constructed for each model. The strain gauges were installed in their grooves. A Universal testing machine was used for unilateral load application of 100 N (N). For each removable partial denture, five measurements were made. The data followed normal distribution and were statistically analyzed by using unpaired t test. P value

Polyaryletherketones (PAEKs) are a family of durable, multifunctional, thermoplastic biopolymers. This article first provides necessary context and thorough information regarding the mechanical, physical, chemical, crystalline, and shape memory properties of PAEKs as well as critical details regarding manufacturing. Additionally, it provides an update on the clinical and biomedical uses of PAEKs by summarizing the most recent and groundbreaking applications of these thermopolymers. PAEKs have been used clinically in fields including orthopedics, craniofacial and cardiothoracic surgery, as well as cardiovascular and dental medicine. Other applications include tissue engineering, post-surgical antibiotic delivery, antimicrobial applications, anti-cancer drug delivery, and 3D printing. Of importance, PAEKs have comparable mechanical strength and elastic modulus to human bone, which enable PAEKs to serve as a viable alternative to metal-based implants. Given their remarkable properties, and ability to be specifically and rapidly manufactured through 3D printing, PAEKs will continue to be a subject of biomedical research and serve a vital role in medical applications.

Current transcathether heart valves rely on metal mesh stents, resulting in discontinuous stent‐leaflet interfaces that introduce stress concentrations, reducing valve lifetime. This work aims to investigate non‐conventional methods to create a fully polymeric transcatheter heart valve, exhibiting a quasi‐continuous interface with hemocompatible leaflets with high durability potential. Polyetheretherketone (PEEK) is of particular interest as a cardiovascular material due to hemocompatibility and mechanical resilience, highly relevant for catheter delivered valves. For increased reproducibility and design freedom, an autoclave process was used to manufacture thin‐ply PEEK composite stents. We demonstrated that a suitable membrane material during manufacturing is essential to evenly distribute pressure around the stent. Meanwhile, a modified vacuum forming process was used to simultaneously form and attach PEEK leaflets to the stent using a heated mold. This simple and robust method enables rapid manufacturing of an integral PEEK‐based valve design, resulting in improved stent‐leaflet bonding, demonstrating an alternative to conventional dip‐coating. The customized vacuum forming causes a controlled annealing effect in semicrystalline materials such as PEEK. Processing PEEK leaflets at higher mold temperatures results in higher crystallinity, elastic modulus, and bond strength. These processes enable greater design flexibility and promote composite materials for use in heart valve devices. Highlights: Developed manufacturing processes for PEEK‐based heart valve implants.Proof of concept for thermoforming of semi‐crystalline PEEK leaflets.Demonstrated effect of processing temperature on valve mechanical properties.Autoclave processing and vacuum forming enable new heart valve designs. [ABSTRACT FROM AUTHOR]

Background: Multi-rooted teeth with extensive dental defects often face challenges in stability and biomechanical failure. High-performance polymer PEEK materials, with properties closer to dentin, show promise in reducing stress concentration and preserving tooth structure. This report aimed to explore the use of a highly retentive polyetheretherketone (PEEK) for manufacturing custom-made split post and core for the restoration of grossly destroyed endodontically treated molars. Clinical considerations: A 40-year-old female patient presented with complaints of loss of tooth substance in the posterior mandibular tooth. This case involved the digital design and fabrication of PEEK split post and core to restore multirooted molar with insufficient dental tissue remnants. The restorations were evaluated over a 3-year follow-up using the World Federation criteria (FDI). The restoration was clinically evaluated through intraoral examination, radiographic assessment, and subjective patient satisfaction, and was deemed clinically good according to FDI criteria. Conclusion: The outstanding mechanical properties of PEEK, coupled with the structure of the split post, provide an effective treatment option for weakened multirooted teeth. Simultaneously, the restoration configuration effectively addressed the challenge of varying postinsertion directions, and the interlocking mechanism between the primary and auxiliary posts enhanced the stability of the post and core. [ABSTRACT FROM AUTHOR]

Studies on dental implant abutments' geometric design and material selection offer significant innovations and results. These studies aim to improve the abutments' functionality and aesthetic performance, minimize microcavities' formation, and ensure implant-supported prostheses' longevity. For example, CAD-CAM fabricated custom abutments have been found to produce a better marginal fit and fewer microgaps than standard abutments. In an in vitro study, transepithelial abutments offered lower microgap values than titanium-based abutments and provided a better fit at the implant–abutment interface. It is known that studies to improve mechanical and biological performance with Polyether Ether Ketone (PEEK) material have been addressed. New materials such as PEEK and zirconia have offered significant advantages in biocompatibility and aesthetics. Along with those studies, different abutment designs are also important. Abutment geometry is optimized to improve stress distribution and minimize peri-implant bone loss. In implant and abutment connections with different angles, mechanical life performances may vary depending on static and dynamic load. These studies emphasize the importance of material research on different types of connections to improve dental implants' durability, homogeneous load distribution, and reliability. The abutment parts used in implant treatment are insufficient to distribute the load homogeneously against chewing pressure due to their materials and geometry. Non-uniform load distribution damages the abutment and the prosthetic crown, accelerating the wear process. This study aimed to create different abutment designs to improve dental implants' biomechanical performance and longevity. This study aimed to increase the mechanical durability of the implant–abutment connection by reducing stress concentrations in response to masticatory compression on the abutment in different directions and forces and to guarantee the long-term success of the implant system by providing a more homogeneous stress distribution. It aimed to apply different forces in the axial direction to these models in a simulation environment and to calculate and compare the deformation and stress load distribution. As a method, three-dimensional models of the parts used in implant treatments and forming the implant system were designed. Different abutment designs were created with these models. Taking the current material values used in implant treatments as a reference, finite element analysis (FEA) was performed by applying different axial loads to each implant system model in the ANSYS software (version 24.1). Comparative analysis graphs were prepared and interpreted for the stress values obtained after the applied load. This study evaluated the mechanical performance of different abutment models (A, B, C, D, and E) under a 100 N load using the Kruskal–Wallis test. The Kruskal–Wallis test showed significant differences between the groups (p < 0.001). The greatest difference was observed between models E and A (q′ = 6.215), with a significant difference also found between models C and A (q′ = 3.219, p < 0.005). Regarding stress values, the highest stress on the abutment was observed in Model B (97.4 MPa), while the lowest stress was observed in Model E (9.6 MPa). The crown exhibited the highest stress in Model B (22.7 MPa) and the lowest in Model E (17.3 MPa). The implant stress was highest in Model C (14.8 MPa) and lowest in Model B (11.3 MPa). The stress values for the cortical bone and cancellous bone were quite similar across the models, showing no significant differences. These findings indicate that the abutment design and material selection significantly impact mechanical performance. Among the implant systems created with five different abutment models, in which the existing abutment geometry was also compared, homogeneous and axial distribution of the load on the abutment was achieved, especially with viscoelastic and surface area increased abutment designs. Clinically, the inadequacy and limited mounting surface or geometry of the abutments used in today's implant treatment applications have led to different design searches. It was concluded that the designs in this study, which are considered alternatives to existing abutment models, contribute positively to the mechanical life of the abutment material, considering the von Mises stresses and directions. This study brings a new perspective to today's practices and offers an alternative to treatment practices. [ABSTRACT FROM AUTHOR]

Achieving a strong bond between Polyetheretherketone (PEEK) and veneering composites is challenging due to PEEKs low surface energy. This study examined the effects of sandblasting and bonding on the shear bond strength (SBS) between veneering composite and pigmented PEEK, considering artificial aging. Of three pigmented PEEK compounds (DC4420R, DC4450R, DC4470R; Evonic Operations GmbH, Marl, Germany), 40 specimens each were milled and polished up to 2500 grit. Prior to veneering, specimens were divided into 4 subgroups: Subgroup 1: Polishing; 2: Polishing + bonding; 3: Sandblasting; 4: Sandblasting + bonding. Sandblasting was performed using Al 2 O 3. Adhesive was an agent containing MMA (Signum Universal Bond, Kulzer GmbH, Hanau, Germany). After veneering (Composite, Kulzer GmbH) the subgroups were divided into 2 subgroups. One subgroup was immersed in 37 °C warm distilled water for 24 h. The second subgroup was artificially aged by thermocycling (TCL) with 5000 cycles in distilled water (5 °C / 55 °C; 30 s). Surface roughness, water contact angles and failure modes were recorded. SBS was measured using a universal testing machine. Results demonstrated that the combination of sandblasting and bonding significantly improved the SBS compared to polishing alone. PEEK color did not significantly influence the SBS. Aging by TCL had a negative effect on the SBS. Sandblasting and the use of an adhesive containing MMA were found to be effective in achieving satisfactory SBS between veneering composite and pigmented PEEK surfaces. These pretreatment methods demonstrate their potential for establishing durable and reliable bonding in clinical applications. [ABSTRACT FROM AUTHOR]

In practical application, continuous drive friction welding (CDFW) has low-energy consumption in the welding field. Polyetheretherketone (PEEK) is a high-performance engineering thermoplastic that belongs to the polyaryletherketone family. PEEK is known for its exceptional mechanical, thermal, and chemical properties, making it suitable for a wide range of applications in various industries. However, many pores were found in the weld interface, showing the mechanical properties of PEEK welded samples are limited. To solve this problem, this study proposed an innovative progressively increased welding area (PIWA) method to reduce pores inside the weld interface. The experimental results showed that the bending strength of the PEEK welded samples using optimal process parameters can be increased by approximately 66% compared with the maximum bending strength of 180 MPa using the conventional method with a cone angle of 180°. The proposed PIWA method has industrial applicability and practical value because this technique can enhance the mechanical properties of PEEK welded samples under low environmental pollution and energy consumption. Two distinct welding mechanisms of PEEK biomedical material were observed. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the effect of carbon nanotubes on the electromagnetic shielding and electrical conductivity of polyetheretherketone(PEEK). The modified multi-walled carbon nanotubes (mMWCNT) was prepared using cetyltrimethylammonium bromide (CTAB) as a dispersing agent. The PEEK/mMWCNT composits were prepared by the processing technology of wet mixing and extrusion blending. The results showed that the mMWCNT were well-dispersed in PEEK matrix, which provided strong support for improving the mechanical and electrical properties of the composites. When the mMWCNT mass fraction was lower than 2.0%, the mechanical properties of PEEK/mMWCNT composites were significantly improved. The mMWCNT formed a 3D network with good conductivity in PEEK. In terms of electromagnetic shielding performance, the total electromagnetic shielding efficiency of PEEK/mMWCNT composites ranged from 3.35 dB to 24.47 dB, which indicated a good absorption of X-band electromagnetic waves. This study confirmed that PEEK/mMWCNT composites have superior electrical conductivity and electromagnetic shielding properties. Hence, the composites have a wide application potential in electronic equipment, communication technology and military protection. [ABSTRACT FROM AUTHOR]

Background: Screws for graft fixation are available in 3 different materials for anterior cruciate ligament reconstruction (ACLR) with the Tape Locking Screw (TLS) technique: titanium, poly- l -lactic acid bioabsorbable, and polyetheretherketone (PEEK). Purpose: To compare the effect of the 3 different fixation materials on graft and implant survival after ACLR with the TLS technique. Study Design: Cohort study; Level of evidence, 3. Methods: Included were 521 patients from the French Prospective ACL Study (FAST) cohort who underwent primary surgical ACLR with the TLS technique. Patients were divided into 3 groups depending on the type of screw material used: titanium (TLS-T group), poly -l -lactic acid bioabsorbable (TLS-B group), or PEEK (TLS-P group). The primary endpoint was a retear within 2 years after ACLR. The secondary endpoints were complication rate, return to sports rate, and functional scores. Objective and subjective functional scores—including the International Knee Documentation Committee, the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Lysholm score—were evaluated preoperatively and at the 2-year follow-up. Pain was assessed with the KOOS-Pain subscore recorded pre- and postoperatively every 6 months up to 2 years. Patient satisfaction was recorded at the 2-year follow-up. Results: No significant differences between the study groups were found in retear rates (4.4%, 4.5%, and 4.3% in the TLS-T, TLS-P, and TLS-B groups 2 years after surgery) or subjective and objective outcomes. The TLS-T group had the lowest rate of intraoperative implant-related complications (0.9%) compared with the TLS-P (4.3%) and TLS-B (7.7%) groups. Young age was a significant risk factor for retear in the TLS-T (P =.03) and TLS-B (P =.0001) groups, while a high level of sports was found to be a significant risk factor in the TLS-P (P =.04) group. All functional scores improved significantly at the 2-year follow-up (P <.0001), with no significant group difference. The KOOS-Pain subscore improved continuously with no significant group difference. The rate of return to preinjury sports was between 43.4% and 58.6%. The rate of highly satisfied patients at the final follow-up was between 86.2% and 91.8%. Conclusion: There was no difference in retear rate or objective and subjective functional scores between implant materials for TLS ACLR in this study. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: This in vitro study was conducted to compare the fracture resistance of tooth restoration complex restored with polyetheretherketone (PEEK) and lithium disilicate endocrowns. Materials and Methods: A total of 46 extracted premolars were collected and treated endodontically. The teeth were mounted in cylindrical molds using autopolymerizing resin and were prepared for endocrown restoration. Specimens were divided into two groups (n = 23) to receive endocrowns made with two different materials (polyetheretherketone and lithium disilicate). All the specimens were subjected to thermal cycling. The fracture resistance test was carried out using a Universal Testing Machine. Fractographic analysis was carried out using stereomicroscope and scanning electron microscope after load test. The values obtained were subjected to statistical analysis. Intergroup comparison (two groups) was performed using a t‐test. Comparison of frequencies of categories of variables with groups was performed using chi‐square test. Results: Fracture resistance tests showed a statistically significant difference in values between the two groups (p < 0.01). High fracture resistance values were seen with lithium disilicate endocrowns. Failure mode analysis showed that both groups exhibited mainly catastrophic failure. There were no significant differences in frequencies of the type of fracture between the groups. Conclusion: The fracture resistance of endocrowns fabricated with lithium disilicate material was found to be significantly higher than polyetheretherketone (PEEK) material. Hence, lithium disilicate material is superior for endocrowns. [ABSTRACT FROM AUTHOR]

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This study presents a scanning electron microscopy analysis of a failed PEEK retainer in an orthodontic patient. After 15 months of use, the patient reported a gap opening between teeth 41 and 42. The PEEK retainer was removed and sent for electron microscope analysis. To investigate the failure, scanning electron microscopy was employed to assess the microstructure and composition of the retainer at various magnifications. These findings suggest that the failure of the PEEK retainer was multifaceted, implicating factors such as material defects, manufacturing flaws, inadequate design, environmental factors, and patient-related factors. In conclusion, this scanning electron microscopy analysis offers valuable insights into the failure mechanisms of PEEK retainers in orthodontic applications. Further research is necessary to explore preventive strategies and optimize the design and fabrication of PEEK retainers, minimizing the occurrence of failures in orthodontic practice. [ABSTRACT FROM AUTHOR]

Aim: Synthetic inorganic materials are commonly used as reinforcing agents in polyetheretherketone (PEEK) composite, whereas natural organic plant-based reinforcing agents are negligible. Surface hardness, roughness, and wettability are indicative factors of osseointegration behavior to be used as an implant material. This study evaluated micro surface hardness (MSH), nano surface hardness (NSH), surface roughness (SR), and contact angle (CA) of PEEK-Azadirachta indica reinforced at 10 wt%, 20 wt%, and 30 wt%. Settings and Design: This was an in vitro study. Materials and Methods: Neem (A. indica) leaf nanoparticles were prepared and reinforced with PEEK powder at 10%, 20%, and 30% weight ratios by injection molding. Sixty specimens underwent the microhardness and CA testing using a digital microhardness tester, and CA goniometer, respectively, and later nanoindentation test to analyze the nanohardness and SR. Statistical Analysis Used: A one-way ANOVA test with a 95% confidence interval for MSH and NSH, SR, and CA was performed on the samples. A post hoc Bonferroni test was conducted (α = 0.05) to compare the groups. Results: There was a significant increase in nanohardness (P = 0.000) with zero difference in microhardness (P = 0.514). The addition of 10 wt%, 20 wt%, and 30 wt% nanoparticles increased the SR value of the pure PEEK from 273.19 nm to 284.10 (3.99%), 296.91 (8.68%), and 287.54 (5.24%), respectively. In the analysis of the CA, CA 20% shows the lowest angle (63.69) with the highest for control specimens (82.39). There is an increase in the PEEK composite SR with a decrease in CA. Conclusions: The addition of plant-derived nanoparticles into the PEEK matrix has a significant impact on the hardness and hydrophobicity enhancing cell growth and osteoblastic differentiation during osseointegration of dental implants. [ABSTRACT FROM AUTHOR]

Aim: This study investigates the interaction of zirconia and polyetheretherketone (PEEK) with indirect composite in fixed dental prostheses. This investigation aimed to assess the shear bond strength (SBS) and color stability of zirconia and PEEK before and after aging, addressing critical concerns in dental restorative applications. Settings and Design: The current in vitro study used 96 samples, 48 of which were divided into two groups, zirconia and PEEK, before and after thermocycling. A dual-axis chewing simulator was used for thermocycling. SBS was measured using a universal testing machine, and color stability was checked using a reflective spectrophotometer. Materials and Methods: Ninety-six samples were categorized into zirconia and PEEK groups, each with subgroups undergoing thermocycling. Samples were prepared using computer-aided design/computer-aided manufacturing milling and veneered with composite resin. Thermocycling involved 10,000 cycles, simulating stress levels equivalent to approximately 1 year of clinical use. SBS was assessed using standardized tests. Stereomicroscopic analysis was performed to evaluate the type of failure. Color stability of the core materials with indirect composite was done using a spectrophotometer before and after aging. Statistical Analysis Used: Statistical analysis included paired t-tests and independent t-tests in SPSS software. Results: The results revealed that SBS values for composite on PEEK decreased from 13.86 ± 0.164 MPa before thermocycling to 13.46 ± 0.185 MPa after thermocycling, with a significant difference (P < 0.005). However, both pre- and postthermocycling values for PEEK were higher than zirconia. The t-test confirmed the lower bond strength of composite to zirconia, with a noteworthy improvement after aging. Stereomicroscopic images revealed adhesive failure for the zirconia group and mixed (adhesive and cohesive) failure for the PEEK group. ΔE values were 3.21 ± 0.127 and 2.93 ± 0.142 for zirconia and PEEK groups, respectively (P < 0.005). Conclusion: Within the limitations of this study, it can be deduced that PEEK is a feasible substitute for zirconia when used in conjunction with indirect composite for the fabrication of dental prostheses. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) are increasingly becoming a potential treatment approach for bone injuries due to the multi-lineage differentiation potential, ability to recognize damaged tissue sites and secrete bioactive factors that can enhance tissue repair. The aim of this work was to improve osteogenesis of carbon fibers reinforced polyetheretherketone (CF/PEEK) implants through bone marrow mesenchymal stem cells (BMSCs)-based therapy. Moreover, bioactive graphene oxide (GO) was introduced into CF/PEEK by grafting GO onto CF to boost the osteogenic efficiency of BMSCs. Subsequently, CF/PEEK was implanted into the symmetrical skull defect models of SD rats. Then in vivo biosafety and osteogenesis were evaluated. The results indicated that surface wettability of CF/PEEK was effectively improved by GO, which was beneficial for the adhesion of BMSCs. The pathological tissue sections stained with H&E showed no significant pathological change in the main organs including heart, liver, spleen, lung and kidney, which indicated no acute systemic toxicity. Furthermore, bone mineralization deposition rate of CF/PEEK containing GO was 2.2 times that of pure CF/PEEK. The X-ray test showed that the surface of CF/PEEK containing GO was obviously covered by more newly formed bone tissue than pure CF/PEEK after 8 weeks of implantation. This work demonstrated that GO effectively enhanced surface bioactivity of CF/PEEK and assisted BMSCs in accelerating differentiation into bone tissue, providing a feasible strategy for improving osteogenesis of PEEK and CF/PEEK. [ABSTRACT FROM AUTHOR]

Ultra-high-molecular-weight polyethylene (UHMWPE) components for orthopedic implants have historically been integrated into metal backings by direct-compression molding (DCM). However, metal backings are costly, stiffer than cortical bone, and may be associated with medical imaging distortion and metal release. Hybrid-manufactured DCM UHMWPE overmolded additively manufactured polyetheretherketone (PEEK) structural components could offer an alternative solution, but are yet to be explored. In this study, five different porous topologies (grid, triangular, honeycomb, octahedral, and gyroid) and three surface feature sizes (low, medium, and high) were implemented into the top surface of digital cylindrical specimens prior to being 3D printed in PEEK and then overmolded with UHMWPE. Separation forces were recorded as 1.97–3.86 kN, therefore matching and bettering the historical industry values (2–3 kN) recorded for DCM UHMWPE metal components. Infill topology affected failure mechanism (Type 1 or 2) and obtained separation forces, with shapes having greater sidewall numbers (honeycomb-60%) and interconnectivity (gyroid-30%) through their builds, tolerating higher transmitted forces. Surface feature size also had an impact on applied load, whereby those with low infill-%s generally recorded lower levels of performance vs. medium and high infill strategies. These preliminary findings suggest that hybrid-manufactured structural composites could replace metal backings and produce orthopedic implants with high-performing polymer–polymer interfaces. [ABSTRACT FROM AUTHOR]

This study continues the discussion on the surface modification of polymers using an atmospheric pressure plasma (APP) reactor in air. These results complement prior research focusing on nonpolar polymers. Polymers, such as polyethylene terephthalate, polyetheretherketone, and polymethyl methacrylate, containing structurally bonded oxygen are studied, representing a range of properties such as oxygen content, crystalline/amorphous structure, polarity, functionality, and aliphatic/aromatic structure. APP induces superior wetting properties on the hydrophilic polymer surfaces with rapid and uniform modification within 0.5 s of exposure. The amorphous structures undergo additional modification for longer exposure. Moreover, the aliphatic chain structures require longer plasma exposure to reach surface modification equilibrium. The polar polymers reach a limit level of modification corresponding to a minimum water contact angle of about 50°. The surface polarity increases on average by a factor of approximately two. The equilibrium values of the adhesion work attained after post-processing recovery fall within a limited range of about 100–120 mJ/m2. The enhancement of surface functionality through the creation of oxidized groups primarily depends on the initial oxygen content and reaches a limit of about 40 at.% oxygen. The surface properties of the treated polar surfaces exhibit good stability, comparable to that of the previously tested nonpolar polymers. [ABSTRACT FROM AUTHOR]

Copolyetheretherketones (co-PEEKs) with high performance characteristics have been obtained by means of a nucleophilic substitution reaction in a high-boiling solvent. The constitution, structure and basic properties of the synthesized polyesters have been studied. The constitution of polymer materials has been confirmed by IR spectroscopy and turbidimetric titration. It has been shown that co-PEEKs can find wide application as highly heat-resistant structural polymer materials. [ABSTRACT FROM AUTHOR]

Aim. This study aimed to evaluate the peri-implant soft tissue response to customized healing abutments (CHAs) made of titanium and polyetheretherketone (PEEK). Methods. Titanium and PEEK CHAs were mounted on bone-level dental implants in bilateral edentulous patients in a randomized split-mouth study design. After a three-week healing period, the clinical parameters of the peri-implant soft tissues were assessed. The value of marginal bone resorption was measured by cone-beam computed tomography. In addition, peri-implant crevicular fluid samples were obtained to identify periodontal pathogenic bacteria, cytokine levels, and active neutrophil collagenase (aMMP-8) concentration. Microcirculation and oxygenation parameters were assessed using laser Doppler flowmetry and optical tissue oximetry. In addition, wavelet analysis was conducted to study blood flow control mechanisms. Results. Out of the 23 participants initially recruited, 20 were assessed after titanium and PEEK CHA installation due to losses to follow-up. The peri-implant soft tissue around 27 titanium and 25 PEEK CHAs was evaluated during follow-ups. No differences were found in the values of marginal bone resorption, cytokine levels, or total bacterial load (p>0.05). PEEK CHAs demonstrated lower bleeding on probing values, less plaque accumulation, and faster relief of ischemia and hypoxia. Although aMMP-8 concentration was higher in the PEEK group, the values were within normal limits. Conclusions. The results of this comparative study showed a positive soft tissue response to PEEK CHAs. However, further studies comparing the effectiveness of different materials for CHAs should be carried out, considering their specific physical properties and processing protocols.

Background The aim of this study was to compare the fracture strength and fracture modes of post-cores produced with CAD-CAM from modified polyetheretherketone (PEEK) materials with other custom-produced post-cores. Methods Sixty human mandibular first premolars with equal root sizes were used. The teeth were divided into six groups (n = 10), and root canal treatment was performed. The teeth were separated from the roots over 2 mm from the cemento-enamel junction. As a result of the decoronation process, a 1 mm wide shoulder line was obtained for all teeth. For the fracture strength test, 10 mm deep post spaces were created on the teeth with a 1.6 mm diameter driller. Post-core groups consisted: everStick® glass fiber post-core (Group GF), zirconia post-core (Group Z), metal (Cr-Co) post-core (Group M), PEEK post-core without filler (Group UP), PEEK post-core with 20% TiO2 Filler (Group TP), and post-core with 20% ceramic filler (Group CP). Following the application of posts to post spaces, copings were created and cemented on the samples. With the universal tester, a force was applied to the long axis of the tooth with a slope of 135°. The mean fracture strength (N) between the groups was statistically evaluated using one-way ANOVA, and pairwise mean differences were detected using post hoc Tukey’s HSD test among the groups. Results According to the results of the statistical analysis, a significant difference was found between the groups in terms of mean fracture resistance (p 0.05). Among all the groups, Group Z exhibited a higher prevalence of repairable failure modes, while the rest of the groups predominantly experienced irreparable failure modes. Conclusion In our study, zirconia and metal post-core samples showed higher average fracture strength values than PEEK post-cores groups. Repairable failure modes were more common in the zirconia post-cores, whereas the opposite was observed in the other groups. Further experimental and clinical trial studies are needed before PEEK materials can be used as post materials in the clinic.

Bio-medical implants and prostheses are made of metals and their alloys and are prone to corrosion and wear. Therefore, it seems necessary to develop lightweight reinforced polymer composites with enhanced properties.

Objective By investigating the retention and fatigue performance of polyetheretherketone(PEEK) clasps with increased proportions of clasp arm engaging the undercut, an innovative method to improve PEEK clasps’ performance was proposed and verified. Methods Three groups of PEEK clasps(n=10/group) with the terminal 1/3, 2/3 and whole of their retentive arms engaging the 0.75 mm undercut were designed and fabricated respectively along with a group of cobalt-chrome clasps(n=10) with their terminal 1/3 of retentive arms engaging the 0.25 mm undercut. Retentive forces were recorded initially and every 1 500 cycles for a total of 15 000 insertion and removal fatigue cycles. Optical scanning and software analysis were applied to evaluate the deformation of the clasps by root mean square (RMS) after fatigue test. The inner surface morphology of clasps’ arms was observed by scanning electron microscopy. Results PEEK clasps with the whole of their retentive arms engaging the undercut exhibited highest mean retentive force (9.24±1.78) Namong other PEKK clasps, which was slightly lower than that of cobalt-chrome clasps (11.88±2.05) N. The retentive force of each group turned out to be reduced after fatigue cycles and cobalt-chrome clasps showed the greatest reduction (38.38%). The RMS of the PEEK clasps groups were of no statistical difference (P=0.111) and were lower than that of cobalt-chrome clasps (105.47±10.82) μm. Evidence of surface abrasion was observed on all groups of clasps especially on the section that engaged the undercut. Conclusion Increasing the proportion of PEEK clasp arm engaging the undercut effectively improved the retentive force and satisfied clinical requirements after fatigue cycles. PEEK clasps exhibited greater retention stability than cobalt-chrome clasps. It is feasible to improve the performance of PEEK clasps by increasing the proportion of clasp arm engaging the undercut.

Abstract Background The rising demand for improved aesthetics has driven the utilization of recently introduced aesthetic materials for creating custom post and core restorations. However, information regarding the fracture resistance of these materials remains unclear, which limits their practical use as custom post and core restorations in clinical applications. Aim of the study This study aimed to evaluate the fracture resistance of three non-metallic esthetic post and core restorations and their modes of failure. Materials and methods Thirty-nine single-rooted human maxillary central incisors were endodontically treated. A standardized post space preparation of 9mm length was performed to all teeth to receive custom-made post and core restorations. The prepared teeth were randomly allocated to receive a post and core restoration made of one of the following materials (n=13): glass fiber-reinforced composite (FRC), polyetheretherketone (PEEK) and polymer-infiltrated ceramic-network (PICN). An intraoral scanner was used to scan all teeth including the post spaces. Computer-aided design and computer-aided manufacturing (CAD-CAM) was used to fabricate post and core restorations. Post and core restorations were cemented using self-adhesive resin cement. All specimens were subjected to fracture resistance testing using a universal testing machine. Failure mode analysis was assessed using a stereomicroscope and SEM. The data was statistically analyzed using One-Way ANOVA test followed by multiple pairwise comparisons using Bonferroni adjusted significance level. Results Custom PEEK post and core restorations displayed the least fracture load values at 286.16 ± 67.09 N. In contrast, FRC exhibited the highest average fracture load at 452.60 ± 105.90 N, closely followed by PICN at 426.76 ± 77.99 N. In terms of failure modes, 46.2% of specimens with PICN were deemed non-restorable, while for PEEK and FRC, these percentages were 58.8% and 61.5%, respectively. Conclusions Within the limitation of this study, both FRC and PICN demonstrated good performance regarding fracture resistance, surpassing that of PEEK.

PurposeThe aim of the in vitro study was to compare the internal merge and marginal perfection of polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) crowns under a stereomicroscope. MethodsAll-ceramic preparation is done on the maxillary first premolar which is mounted on the wax block which was scanned using 3Shape scanner and duplicated into 30 acrylic CAD/CAM dies (n = 15) for the placement of PEEK and PEKK crowns. The YENADENT milling system was used to fabricate 15 samples from Group A PEEK crowns and to fabricate 15 samples from Group B PEKK crowns. According to the manufacturer’s instructions, an equal amount of the dual-cure resin luting agent (Rely X U200 Self-Adhesive resin, 3M, Germany) was dispensed on the mixing pad before being mixed with cement and painted on the internal surfaces of the copings with the finger pressure crowns which were luted. The values were then analyzed using one-way ANOVA (post hoc) followed by Dunnett’s t-test. ResultsAmong those two groups, PEEK group materials showed the lowest mean value of (28.73.3 ± 4.01) for marginal fit and (26.72 ± 2.53) for internal gap, whereas PEKK group showed a mean value of (32.85 ± 4.63) and (33.06 ± 4.14), respectively. ConclusionAmong these two groups, comparatively less marginal fit and internal adaptation is seen in PEKK when compared to the PEEK crowns. While the marginal fit and internal adaptation of both PEEK and PEKK copings were in acceptable clinical range.

Objective To study the clinical effect of a polyetheretherketone (PEEK) bonding bridge on the loss of 3 internal incisors in patients with periodontitis. Methods This study was reviewed and approved by the ethics committee, and informed consent was obtained from the patients. Thirty-eight patients with periodontitis and 3 missing central or lateral teeth were selected to undergo restoration with a PEEK bonding bridge and then returned to the hospital 3, 6, 12, and 24 months after the restoration was completed. The survival rate of the restorations was assessed by the modified USPHS/Ryge criteria. The plaque index, gingival index, periodontal probing depth and attachment loss of the abutments were recorded, and the changes in periodontal tissues after restoration were observed and compared. Results Over 24 months of clinical follow-up observation of 38 patients, only 1 patient underwent secondary bonding after partial debonding (evaluated as grade B), while bonding was successful in the other 37 cases (evaluated as grade A). The plaque index, gingival index and periodontal probing depth were significantly lower after restoration than before (PP>0.05). Conclusion For periodontitis patients missing 3 internal incisors, short-term PEEK bonding bridge repair has good clinical efficacy.

As the main means of mastication, teeth can withstand countless functional contacts. The mechanical properties of teeth are closely related to their tissue structure. Enamel and dentin have a high hardness and modulus of elasticity, and their graded structure allows them to withstand bite forces without being susceptible to fracture. When tooth tissue is defective, full crown restoration is often needed to restore the normal shape and function of the tooth. Metal materials, ceramic materials, and polyetheretherketone (PEEK) materials are commonly used for crown restoration. Metal materials have certain disadvantages in terms of aesthetics and are relatively rarely used in clinical practice. Ceramic materials with different compositions exhibit differences in performance and aesthetics, but their elastic modulus and hardness are much higher than those of dental tissue, resulting in mismatching mechanical properties. In contrast, the elastic modulus of PEEK is lower than that of tooth tissue and similar to that of bone tissue, but its properties can be improved by fiber reinforcement. Notably, when the mechanical properties of a restoration material and tooth tissue are not fully matched, the interface between them often forms a potential weak link, which ultimately affects the stability and long-term effect of the restoration. This article introduces the mechanical properties and corresponding structural characteristics of enamel and dentin. On this basis, the advantages and limitations of existing restoration materials are analyzed, and the possibility of biomimetic design of full crowns is further explored.

A new method is proposed for assessing the wear resistance of polymer materials according to the “finger — disk” friction scheme. It involves changing the geometry of the friction zone of polymer samples — the “finger” sphere is replaced by a truncated cone. The developed method is tested on samples of polyetheretherketone (PEEK) and polymer composite materials (PCM) based on polytetrafluoroethylene (PTFE, fluoroplast-4), in particular, obtained after laser ablation with the addition of carbon fibers. The relevance lies in simplifying the manufacture of samples, as well as the possibility of quickly changing the geometric parameters of their working part, which expands the scope of the method with respect to the latest polymer materials and composites based on them. The practical significance of the results is confirmed by their use at such enterprises as JSC “Grodno Azot” and JSC “Grodno Mechanical Plant”, which serially produce tribotechnical PCM.

Polyetheretherketone (PEEK) has become a promising material for bone engineering due to its excellent mechanical properties, radiolucency and chemical resistance. However, its inherent bioinertness and lack of osteogenic activity induce a foreign body reaction and fibrous encapsulation, which limits its effectiveness in promoting bone regeneration. Herein, we develop a novel bioactive glass–functionalized PEEK scaffold (ADSP) to accelerate bone regeneration by immunoregulation. Strontium-doped bioactive glass nanoparticles loaded with alendronate (A-SrBG) were coated on the sulfonated PEEK scaffold by the strong adhesion ability of polydopamine. The released bioactive ions from the scaffold can improve the biocompatibilities and osteogenic activity of PEEK. In vitro results showed the ADSP scaffold promoted polarization of the M2 macrophages via the NF-κB pathway to enhance the osteogenic differentiation of rat bone mesenchymal stem cells (rBMSCs). Further, in vivo rat skull drilling model assessment revealed efficient polarization of M2 macrophage and desirable new bone formation. Thus, ADSP scaffold exerted osteoimmunomodulation effect to promote bone regeneration.

Polyetheretherketone (PEEK), an organic thermoplastic polymer, has gained interest in dentistry due to its excellent mechanical strength, flexibility, and biocompatibility. Furthermore, the ability to utilize CAD/CAM in the fabrication of PEEK enhances accuracy, reliability, and efficiency while also saving time. Hence, several orthodontic studies have explored the utilization of PEEK in various applications, such as archwires, brackets, fixed lingual retainers, palatal expansion devices, transpalatal arches, Tübingen palatal plates, different types of space maintainers, mini-implant insertion guides, and more. However, a complete systematic review of the available data comparing the performance of PEEK with traditional orthodontic materials has not yet been conducted. Therefore, this systematic review seeks to assess if PEEK material meets the required mechanical criteria to serve as an alternative to conventional orthodontic appliances. To ensure clarity and precision, this review will specifically concentrate on fixed appliances. This systemic review followed the PRISMA guidelines and utilized databases including PubMed/MEDLINE, Embase, Springer, Web of Science, and Wiley. Searches were restricted to English language articles from January 2013 to February 2024. Keywords such as "Polyetheretherketone" or "PEEK" and "Orthodontic" or "Orthodontic device" or "Orthodontic materials" were employed across all databases. Nine studies were incorporated, covering orthodontic archwires, brackets, and fixed lingual retainers. Based on the reviewed literature, PEEK demonstrates promising potential in orthodontic fixed appliances, offering advantages in force delivery, friction reduction, and aesthetic appeal. Further research is needed to fully explore its capabilities and optimize its application in clinical practice. [ABSTRACT FROM AUTHOR]

Background: The rising demand for improved aesthetics has driven the utilization of recently introduced aesthetic materials for creating custom post and core restorations. However, information regarding the fracture resistance of these materials remains unclear, which limits their practical use as custom post and core restorations in clinical applications. Aim of the study: This study aimed to evaluate the fracture resistance of three non-metallic esthetic post and core restorations and their modes of failure. Materials and methods: Thirty-nine single-rooted human maxillary central incisors were endodontically treated. A standardized post space preparation of 9mm length was performed to all teeth to receive custom-made post and core restorations. The prepared teeth were randomly allocated to receive a post and core restoration made of one of the following materials (n=13): glass fiber-reinforced composite (FRC), polyetheretherketone (PEEK) and polymer-infiltrated ceramic-network (PICN). An intraoral scanner was used to scan all teeth including the post spaces. Computer-aided design and computer-aided manufacturing (CAD-CAM) was used to fabricate post and core restorations. Post and core restorations were cemented using self-adhesive resin cement. All specimens were subjected to fracture resistance testing using a universal testing machine. Failure mode analysis was assessed using a stereomicroscope and SEM. The data was statistically analyzed using One-Way ANOVA test followed by multiple pairwise comparisons using Bonferroni adjusted significance level. Results: Custom PEEK post and core restorations displayed the least fracture load values at 286.16 ± 67.09 N. In contrast, FRC exhibited the highest average fracture load at 452.60 ± 105.90 N, closely followed by PICN at 426.76 ± 77.99 N. In terms of failure modes, 46.2% of specimens with PICN were deemed non-restorable, while for PEEK and FRC, these percentages were 58.8% and 61.5%, respectively. Conclusions: Within the limitation of this study, both FRC and PICN demonstrated good performance regarding fracture resistance, surpassing that of PEEK. [ABSTRACT FROM AUTHOR]

Polyetheretherketone (PEEK) is of interest because of its excellent mechanical properties. However, the bioinert nature of PEEK limits its use in clinical applications. In this study, a series of micro/nanostructures combining nano‐, submicron‐, and microscale on PEEK were fabricated with 0.5, 1, 4, and 6 min of sulfonation time (S1, S2, S3, and S4). Compared to the flat surface on PEEK, the micro/nanostructure of different sizes all significantly promote cell adhesion, proliferation, and osteogenic differentiation of MC3T3‐E1 cells. It is shown that micro/nano‐porous structures with smaller size and lower roughness of S1 enabled faster cell propagation. The results of alkaline phosphatase staining, alizarin red staining, and quantitative real‐time PCR reveal that the osteogenic activity of MC3T3‐E1 cells gradually decreases with the increasement of pore size, indicating that the micro/nanostructured topography of S1 generated substantially increased matrix mineralization and bone‐like nodule formation, compared to the 3D network surface. This work provides an effective strategy for designing biomaterials with potential clinical applications. [ABSTRACT FROM AUTHOR]

Polyetheretherketone (PEEK), a biomaterial with appropriate bone-like mechanical properties and excellent biocompatibility, is widely applied in cranio-maxillofacial and dental applications. However, the lack of antibacterial effect is an essential drawback of PEEK material and might lead to infection and osseointegration issues. This study aims to apply a natural antibacterial agent, totarol coating onto the 3D printed PEEK surface and find an optimized concentration with balanced cytocompatibility, osteogenesis, and antibacterial capability. In this study, a natural antibacterial agent, totarol, was applied as a coating to fused filament fabrication (FFF) 3D printed PEEK surfaces at a series of increasing concentrations (1 mg/ml, 5 mg/ml, 10 mg/ml, 15 mg/ml, and 20 mg/ml). The samples were then evaluated for cytocompatibility with L929 fibroblast and SAOS-2 osteoblast using live/dead staining and CCK-8 assay. The antibacterial capability was assessed by crystal violet staining, live/dead staining, and scanning electron microscopy (SEM) utilizing the oral primary colonizer S. gordonii and isolates of mixed oral bacteria in a stirring system simulating the oral environment. The appropriate safe working concentration for totarol coating is selected based on the results of the cytocompatibility and antibacterial test. Subsequently, the influence on osteogenic differentiation was evaluated by alkaline phosphatase (ALP) and alizarin red staining (ARS) analysis of pre-osteoblasts. Our results showed that the optimal concentration of totarol solution for promising antibacterial coating was approximately 10 mg/ml. Such surfaces could play an excellent antibacterial role by inducing a contact-killing effect with an inhibitory effect against biofilm development without affecting the healing of soft and hard tissues around FFF 3D printed PEEK implants or abutments. This study indicates that the totarol coated PEEK has an improved antibacterial effect with excellent biocompatibility providing great clinical potential as an orthopedic/dental implant/abutment material. [Display omitted] • A natural antibacterial coating of totarol was added on 3D-printed PEEK surfaces. • Different totarol concentrations led to varying biocompatibility and antibacterial effect. • A dynamic biofilm formation system was used to mimic the oral clinical environment. • The optimal coating concentration with balanced biocompatibility, osteogenesis and antibacterial efficacy was around 10 mg/ml. • Totarol coated PEEK shed light on a promising candidate for dental implants and abutments. [ABSTRACT FROM AUTHOR]

The current study investigates the melting behavior of polyetheretherketone (PEEK) using both Differential Scanning Calorimetry (DSC) and Fast Scanning Calorimetry (FSC) thermal analysis techniques. The PEEK melting peaks are examined under various conditions, including isothermal and non‐isothermal crystallization conditions, as well as a thermal profile mimicking the material extrusion process (MEX). The results of the analysis reveal changes in the crystalline morphology, as indicated by a shift in intensity between melting peaks crystalized at different isothermal temperatures and cooling rates. Furthermore, the behavior of the deconvoluted melting peaks differs depending on the substrate temperature during the MEX process simulation. The presence of double or multiple melting peaks suggests the presence of different crystalline populations during the manufacturing process. Understanding the formation and changes in these melting peaks can help inform the development of better printing strategies and improve the mechanical performance of printed parts. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the in vitro study was to compare the internal merge and marginal perfection of polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) crowns under a stereomicroscope. Methods: All-ceramic preparation is done on the maxillary first premolar which is mounted on the wax block which was scanned using 3Shape scanner and duplicated into 30 acrylic CAD/CAM dies (n = 15) for the placement of PEEK and PEKK crowns. The YENADENT milling system was used to fabricate 15 samples from Group A PEEK crowns and to fabricate 15 samples from Group B PEKK crowns. According to the manufacturer's instructions, an equal amount of the dual-cure resin luting agent (Rely X U200 Self-Adhesive resin, 3M, Germany) was dispensed on the mixing pad before being mixed with cement and painted on the internal surfaces of the copings with the finger pressure crowns which were luted. The values were then analyzed using one-way ANOVA (post hoc) followed by Dunnett's t-test. Results: Among those two groups, PEEK group materials showed the lowest mean value of (28.73.3 ± 4.01) for marginal fit and (26.72 ± 2.53) for internal gap, whereas PEKK group showed a mean value of (32.85 ± 4.63) and (33.06 ± 4.14), respectively. Conclusion: Among these two groups, comparatively less marginal fit and internal adaptation is seen in PEKK when compared to the PEEK crowns. While the marginal fit and internal adaptation of both PEEK and PEKK copings were in acceptable clinical range. [ABSTRACT FROM AUTHOR]

Study Design: This was a retrospective longitudinal observational study. Purpose: The purpose of this study was to analyze the results of cervical sagittal parameters on preoperative and postoperative lateral radiographs in anterior cervical discectomy and fusion (ACDF). ACDF is believed to change craniocervical parameters and thus cervical curvature using polyetheretherketone (PEEK) or titanium cages with or without self-locking as well as an anterior plate, the latter of which has not been shown to provide better clinical or radiological results. Overview of Literature: Cervical spondylotic myelopathy (CSM) is a common degenerative pathology that can affect one or more levels and treatment has varied over time trying to maintain sagittal parameters within acceptable values where the ACDF is the main treatment. Materials and Methods: The study was performed in patients with CSM who underwent anterior cervical discectomy, and their pre- and postoperative radiographs were analyzed using Surgimap software a few days before and 3 months after surgery. Results: Fifteen files were included in the study. Statistically significant sagittal balance variables were observed in cervical lordosis (CL) with an increase of 4.73° (P = 0.019) and T1 slope (T1S)-CL with a decrease of -5.93° (P = 0.007). Conclusions: CL and T1S-CL showed favorably modified values when performing ACDF using stand-alone PEEK cages without the need for self-blocking or an anterior plate. [ABSTRACT FROM AUTHOR]