Comparison of the polishing effects of polyetheretherketone materials under different chairside polishing systems / 口腔疾病防治

Objective @# The polishing effects of different compositions of chairside polishing systems on polyetheretherketone (PEEK) were compared to provide a reference for the rational selection of polishing systems for this material in clinical settings. @*Methods @#A total of 108 specimens were made from ShushijieTMPEEK crown and bridge materials, Bio-PAEK® dental PEEK, and BioHPP® PEEK. Thirty-six specimens of each material were randomly divided into 6 groups on average based on their polishing technique: OptiDisc®, Super-Snap® Rainbow Technique Kit, VITA ENAMIC®Clinical Polishing Set, Sof-LexTM Diamond Polishing System, Visio.lign Finishing Kit for Composite Veneers, and CERAMAGE Polishing Kit, LavaTM Ultimate ceramic and VITA ENAMIC ceramics were set as the control groups, and 6 specimens were made in each material, polished by Sof-LexTM Diamond Polishing System and VITA ENAMIC® Polishing Set clinical, respectively, according to the manufacturers’ suggestions. The surface roughness (Ra value and Sa value) and gloss of each set were measured. The surface morphologies of the polished specimens were observed by scanning electron microscopy.@*Results @#Surface roughness (Ra value and Sa value) and gloss were mainly influenced by the type of polishing system, and they varied between PEEK material types. The Sof-LexTM Diamond Polishing System produced the highest surface roughness and the lowest gloss values for PEEK materials, while the Super-Snap® Rainbow Technique Kit, Visio.lign Finishing Kit for Composite Veneers and CERAMAGE Polishing Kit resulted in low surface roughness values. The Visio.lign Finishing Kit for Composite Veneers and CERAMAGE Polishing Kit exhibited high gloss values. Polishing paste particles were observed embedded on the surfaces of the PEEK materials polished by the Visio.lign Finishing Kit for Composite Veneers; the surfaces of specimens polished by the CERAMAGE Polishing Kit were smooth, without polishing paste particle residue. Using the same polishing system, the best polishing results were obtained with BioHPP® among the PEEK materials tested. The surface roughness values of the three tested PEEK materials polished by the CERAMAGE Polishing Kit were similar to those of the LavaTM Ultimate ceramic and VITA ENAMIC ceramic, but the gloss was higher than that of both. @*Conclusion @# CERAMAGE Polishing Kit was recommended for polishing all three tested PEEK materials, achieving a good polishing effect, with similar surface roughness and higher gloss characteristics comparable to those of polished computer-aided design and manufacturing (CAD/CAM) resin-matrix ceramics.

Comparison of shear bond strength and color reproduction of two different high-performance polymers veneered with two different thicknesses of resin composite: an in-vitro study / Comparação da resistência ao cisalhamento e reprodução de cor de dois diferentes polímeros de alto desempenho revestidos com duas diferentes espessuras de resina composta: um estudo in vitro

Objective: to evaluate the effect of material type and veneer thickness on the final color and shear bond strength of PEEK bilayered restorations. Material and Methods: sixty-four square-shaped core specimens (7×7×2), were fabricated by CAD/CAM technology from two high-strength polymers, BioHPP (High-Performance Polymer, group B n=32), and Pekkton® ivory (PolyEtherKetoneKetone, group P n=32) then were veneered with resin composite (crea.lign dentin A3). Specimens from each group were divided (n=16) according to the veneer layer thickness (0.5 & 1 mm), then according to the test applied (n=8), either ΔE or shear bond strength (SBS). Specimen surfaces were treated according to the manufacturer's instructions. Specimens were veneered according to the manufacturer's instructions.The mode of failure was evaluated under a stereomicroscope at 40 x magnification after the shear bond strength test. Results: data showed parametric distribution and variance homogeneity and were analyzed using two-way ANOVA. The significance level was set at p<0.05 for all tests. Statistical analysis was performed with the R statistical analysis software version 4.3.1.Results of two-way ANOVA showed that material types and veneer thicknesses had an individual significant effect on the color change. For the shear bond strength, only the sample thickness (1mm) had a significant effect (p=0.033). The majority of samples in different groups presented a mixed failure mode with all the differences being not statistically significant (p>0.05). Conclusion: the thickness of the resin composite veneer can significantly affect the final esthetic outcome and shear bond strength of a bilayered restoration.(AU)

Objetivo: avaliar o efeito do tipo de material e da espessura do revestimento na cor final e na resistência ao cisalhamento de restaurações em duas camadas de PEEK. Material e Métodos: foram fabricados 64 espécimes com núcleo de formato quadrado (7x7x2) usando tecnologia CAD/CAM a partir de dois polímeros de alta resistência, BioHPP (Polímero de Alto Desempenho, grupo B n=32) e Pekkton ivory (Polieterecetona cetona, grupo P n=32), que foram então revestidos com resina composta (crea.lign dentin A3). Os espécimes de cada grupo foram divididos (n=16) de acordo com a espessura do revestimento (0,5 e 1 mm), e depois de acordo com o teste aplicado (n=8), seja ΔE ou resistência ao cisalhamento (SBS). As superfícies dos espécimes foram tratadas de acordo com as instruções do fabricante. Os espécimes foram revestidos de acordo com as instruções do fabricante. O modo de falha foi avaliado sob um estereomicroscópio com ampliação de 40x após o teste de resistência ao cisalhamento. Resultados: os dados apresentaram distribuição paramétrica e homogeneidade de variância e foram analisados por ANOVA de duas vias. O nível de significância foi estabelecido em p<0,05 para todos os testes. A análise estatística foi realizada com o software de análise estatística R, versão 4.3.1. Os resultados da ANOVA de duas vias mostraram que os tipos de materiais e as espessuras do revestimento tiveram um efeito significativo individual na mudança de cor. Para a resistência ao cisalhamento, apenas a espessura da amostra (1mm) teve um efeito significativo (p=0,033). A maioria das amostras em diferentes grupos apresentou um modo de falha misto, com todas as diferenças não sendo estatisticamente significativas (p>0,05). Conclusão:a espessura do revestimento de resina composta pode afetar significativamente o resultado estético final e a resistência ao cisalhamento de uma restauração em duas camadas.(AU)

Application of polyetheretherketone (PEEK) posts: evaluation of fracture resistance and stress distribution in the root: in vitro and finite element analyses

Abstract To evaluate the feasibility of using a milled polyetheretherketone (PEEK) post and core in endodontically treated teeth with or without a ferrule. Sixty bovine tooth roots were endodontically treated followed by cementation of intraradicular retainers (IR), according to each experimental group: a) non-ferrule glass fiber post (f0FP); b) 2-mm-ferrule glass fiber post (f2FP); c) non-ferrule resized glass fiber post (f0PR); d) 2-mm-ferrule resized glass fiber post (f2PR); e) non-ferrule PEEK post and core (f0PPC); and f) 2-mm-ferrule PEEK post and core (f2PPC). Metal crowns were made and cemented. A periodontal ligament was simulated using polyether. A force was applied to the palatine portion of each sample at 45°, until fracture. Fracture resistance data were submitted to two-way ANOVA and Tukey's test (α = 0.05). Three-dimensional digital models were developed to calculate the tensions formed in the root using finite element analysis. Models of glass fiber posts and PEEK posts and cores were evaluated with or without a ferrule. The results were analyzed by the Mohr-Coulomb criterion. The type of IR was not influenced by fracture strength (p = 0.243). There were significant statistical differences among the remaining factors. Ferrule groups had greater fracture resistance, and the failure mode of teeth with a ferrule was more catastrophic than the non-ferrule group. A ferrule increases fracture resistance and influences failure mode; the PEEK post and core did not modify the biomechanics of endodontically treated teeth, and resembled the glass fiber post results. The crack initiation point differed between the ferrule and non-ferrule groups.

The effect of different framework's material on strain induced in distal abutment in mandibular Kennedy's class II: an in-vitro study / O efeito de diferentes materiais de estrutura na deformação induzida na distal do pilar da classe II de Kennedy mandibular: um estudo in vitro

Objective: This study aims to compare the strain induced in the supporting structures of unilateral mandibular removable partial denture frameworks retained by extra-coronal attachments fabricated with three different materials. Material and Methods: Three mandibular class II digitally designed and printed acrylic models with detachable abutments were used to fabricate three removable partial denture framework with extra coronal attachments from three different materials. A total of 33 models were prepared for strain testing (n=11). Models were divided into three groups according to framework's material: porcelain fused to cobalt chromium (PFM), polyetherketoneketone (PEKK) and polyetheretherketone (PEEK) group. Unilateral load of 60 N was applied in the three groups and strains were measured around the main abutment and saddle area using strain gauge. Results: Statistical analysis was performed using Shapiro-Wilk's test and by checking data distribution. Data were found to be non-parametric and were analysed using Kruskal-Wallis test followed by Dunn's post hoc test with Bonferroni correction. PFM group showed significantly the highest strain values around abutment, slot 1 (1mm distal to the socket of the last abutment) and slot 2 (1 cm away from slot 1) respectively (843.00±23.08, 91.00±6.52 and 1274.00±65.71) than the other tested groups (p<0.05) at same tested sites respectively followed by PEKK group (384.00±37.48, 81.00±2.24 and 135.00±0.00) and PEEK group (29.00±4.18, 63.00±4.47 and 52.00±5.70). Conclusions: PEEK and PEKK for partial denture framework with extra coronal attachments are adequate alternative to PFM due to their good mechanical response applying less strain on supportive structures in free-end cases. PEEK induces lower strain magnitude on the supporting structures when compared to PEKK. (AU)

Objetivo: Este estudo tem como objetivo comparar a tensão induzida nas estruturas de suporte de estruturas de próteses parciais removíveis mandibulares unilateraisretidas por encaixes extracoronários fabricados com três materiais diferentes. Material e Métodos: Três modelos mandibulares de classe II digitalmente projetados e impressos em acrílico com pilares destacáveis foram usados para fabricar três estruturas de próteses parciais removíveis com encaixes extracoronários de três materiais diferentes. Um total de 33 modelos foram preparados para testes de deformação (n=11). Os modelos foram divididos em três grupos de acordo com o material da estrutura: porcelana fundida com cobalto-cromo (PFM), poliétercetonacetona (PEKK) e polieteretercetona (PEEK). Carga unilateral de 60 N foi aplicada nos três grupos e as deformações foram medidas em torno do pilar principal e área de sela usando medido de tensão. Resultados: A análise estatística foi realizada por meio do teste de Shapiro-Wilk e com a verificação da distribuição dos dados. Os dados mostraram-se não paramétricos e foram analisados pelo teste de Kruskal-Wallis seguido pelo de Dunn com correção de Bonferroni. O grupo PFM mostrou significativamente os maiores valores de tensão ao redor do pilar, slot 1 (1mm distal do último pilar) e slot 2 (1 cm de distância do slot 1) respectivamente (843,00±23,08, 91,00±6,52 e 1274,00±65,71) do que os outros grupos testados (p<0,05) nos mesmos locais testados, respectivamente, seguido pelo grupo PEKK (384,00±37,48, 81,00±2,24 e 135,00±0,00) e grupo PEEK (29,00±4,18, 63,00±4,47 e 52,00±5,70). Conclusão: PEEK e PEKK para estrutura de prótese parcial com encaixes extracoronários são alternativas adequadas ao PFM devido à sua boa resposta mecânica aplicando menos tensão nas estruturas de suporte em casos de extremidade livre. O PEEK induz menor magnitude de deformação nas estruturas de suporte quando comparado ao PEKK (AU)

Effect of polyetheretherketone cranioplasty following craniectomy for traumatic brain injury / 中华创伤杂志

Objective:To investigate the effect of cranioplasty with polyetheretherketone (PEEK) after craniectomy in patients with traumatic brain injury (TBI).Methods:A retrospective case series study was used to analyze the clinical data of 85 TBI patients undergone craniectomy admitted to Renji Hospital, Shanghai Jiaotong University School of Medicine from February 2017 to April 2021, including 57 males and 28 females, aged 7-70 years [(40.8±15.5)years]. Patients′ Glasgow Coma Scale (GCS) was 6-15 points [15 (13, 15)points]. All patients underwent PEEK cranioplasty as scheduled. The extended Glasgow Outcome Scale (GOSE) was used to evaluate the neurological function before, at 3 and 6 months after operation. After excluding 33 patients with preoperative GOSE score of 8 points, 52 patients with preoperative GOSE score less than 8 points were analyzed on the degree of GOSE improvement. Patients′ satisfaction with PEEK repair was evaluated through telephone interviews at 6 months postoperatively. The incidence of complications were observed during hospitalization and within 6 months postoperatively.Results:All patients were followed up for 6-7 months [6 (6, 7)months]. The GOSE was 6 (5, 8)points before operation, 6 (5, 8)points at 3 months after operation, and 7 (5, 8)points at 6 months after operation. There was no significant difference in GOSE at 3 months after operation and before operation ( P>0.05), but it was significantly increased at 6 months after operation when compared to the preoperative level ( P<0.05). With regards to GOSE, there were 10 patients with mild amelioration but 42 with no amelioration at 3 months after operation, while 4 patients with significant amelioration and 31 with no amelioration were observed at 6 months after operation ( P<0.05). For PEEK repair, Patients′ satisfaction was very high in 43 patients, high in 33, general in 7 and poor in 2. A total of 25 patients had postoperative complications during hospitalization and within 6 months postoperatively, with the incidence of complications of 29%. Specifically, there was 1 patient with wound infection, 1 new epilepsy, 8 epidural hemorrhage, 13 subcutaneous effusion, 1 subcutaneous effusion, severe infection and material exposure, and 1 severe infection, new-onset epilepsy and subcutaneous effusion. Repair materials were removed in 2 patients due to multiple complications; other patients obtained alleviation via treatment, without affect on their daily life. Conclusion:PEEK cranioplasty following craniectomy for TBI patients can improve prognosis, attain high satisfaction and has low incidences of postoperative infection and exposure of repair materials.

Modification of polyetheretherketone (PEEK) physical features to improve osteointegration / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Polyetheretherketone (PEEK) has been widely applied in orthopedics because of its excellent mechanical properties, radiolucency, and biocompatibility. However, the bioinertness and poor osteointegration of PEEK have greatly limited its further application. Growing evidence proves that physical factors of implants, including their architecture, surface morphology, stiffness, and mechanical stimulation, matter as much as the composition of their surface chemistry. This review focuses on the multiple strategies for the physical modification of PEEK implants through adjusting their architecture, surface morphology, and stiffness. Many research findings show that transforming the architecture and incorporating reinforcing fillers into PEEK can affect both its mechanical strength and cellular responses. Modified PEEK surfaces at the macro scale and micro/nano scale have positive effects on cell-substrate interactions. More investigations are necessary to reach consensus on the optimal design of PEEK implants and to explore the efficiency of various functional implant surfaces. Soft-tissue integration has been ignored, though evidence shows that physical modifications also improve the adhesion of soft tissue. In the future, ideal PEEK implants should have a desirable topological structure with better surface hydrophilicity and optimum surface chemistry.

Application prospect of polyetheretherketone in postcore crown restorations / 口腔疾病防治

@#Polyetheretherketone (PEEK) is known as a high-grade engineering plastic with good mechanical properties, chemical stability and biocompatibility. Currently, PEEK materials have been widely used in prosthodontics, such as complete dentures and removable partial dentures. The relevant research shows that PEEK posts are superior to glass fiber posts, which have high tensile bond strength and bending strength. At present, few case reports of PEEK postcores have been published, and clinical case reports suggest that PEEK postcores have good oral prosthetic aesthetics and are ideal and reliable postcore crown materials. However, the preparation and surface treatment methods of PEEK require further refinement. A review of the related properties of PEEK and the prospects of its application in the field of postcore crown restoration will be presented in this paper.

Biomechanical Study of PEEK Condyle Prosthesis Printed by Fused Deposition Modeling and Selective Laser Sintering / 医用生物力学

Objective To make finite element analysis and compressive performance test on three-dimensional (3D) printed personalized poly-ether-ether-ketone (PEEK) condyle prosthesis, so as to analyze stress distribution characteristics and mechanical properties of the prosthesis, and to evaluate its clinical value and prospect. Methods The finite element models of PEEK condyle prosthesis, mandible and fixation screw were established by software such as CBCT, Mimics, Geomagic Studio, SolidWorks and ANSYS Workbench. The maximum mastication force was applied, and the maximum stress of the condyle prosthesis and screw, as well as the stress and strain of the mandible were recorded. In order to simulate the actual clinical situation, a special fixture was designed to test compression performance of the condyle prosthesis prepared by the fused deposition modeling (FDM) and selective laser sintering (SLS) at the rate of 1 mm/min. Results The peak stress of the PEEK condyle prosthesis was 10.733 MPa, which was located at the back of the condyle neck. The peak stress of 5 fixing screws was 9.707 5 MPa, which appeared on the 2# and 5# screws near the trailing edge of the mandibular ascending branch. The peak stress of both the prosthesis and the screw was smaller than its yield strength. The maximum pressure of the condyle prosthesis prepared by FDM and SLS was (3 814.7±442.6) N and (1 193.970±260.350) N, respectively. Compared with the SLS preparation, the FDM prepared prosthesis not only had higher compression strength but also better toughness. Conclusions The 3D printed personalized PEEK condyle prosthesis shows uniform stress distributions and good mechanical properties, which can provide the theoretical basis for PEEK as reconstruction material for repairing temporomandibular joint.

In vivo study of liposome-modified polyetheretherketone implant on bacteriostasis and osseointegration / 北京大学学报(医学版)

OBJECTIVE@#To develop dexamethasone plus minocycline-loaded liposomes (Dex/Mino liposomes) and apply them to improve bioinert polyetheretherketone (PEEK) surface, which could prevent post-operative bacterial contamination, enhance ossification for physiologic osseointegration, and finally reduce implant failure rates.@*METHODS@#Dex/Mino liposomes were covalently grafted onto the PEEK surface using polydopamine (pDA) coating as a medium. Confocal laser scanning microscopy was used to confirm the binding of fluorescently labeled liposomes onto the PEEK substrate, and a microplate reader was used to semiquantitatively measure the average fluorescence intensity of fluorescently labeled liposome-decorated PEEK surfaces. Moreover, the mouse subcutaneous infection model and the beagle femur implantation model were respectively conducted to verify the bioactivity of Dex/Mino liposome-modified PEEK in vivo, by means of micro computed tomography (micro-CT) and hematoxylin and eosin (HE) staining analysis.@*RESULTS@#The qualitative and quantitative results of fluorescently labeled liposomes showed that, the red fluorescence intensity of the PEEK-pDA-lipo group was stronger than that of the PEEK-NF-lipo group (P < 0.05); the liposomes were successfully and uniformly decorated on the PEEK surfaces due to the pDA coating. After mouse subcutaneous implantation of PEEKs for 24 hours, HE staining results showed that the number of inflammatory cells in the PEEK-Dex/Mino lipo group were lower than that in the inert PEEK group (P < 0.05), indicating a lower degree of infection in the test group. These results suggested that the Mino released from the liposome-functionalized surface provided an effective bacteriostasis in vivo. After beagle femoral implantation of PEEK for 8 weeks, micro-CT results showed that the PEEK-Dex/Mino lipo group newly formed more continuous bone when compared with the inert PEEK group; HE staining results showed that more new bones were formed in the PEEK-Dex/Mino lipo group than in the inert PEEK group, which were firmly bonded to the functionalized PEEK surface and extended along the PEEK interface. These results suggested that the Dex released from the liposome-functionalized surface induced effective bone regeneration in vivo.@*CONCLUSION@#Dex/Mino liposome modification enhanced the bioactivity of inert PEEK, the functionalized PEEK with enhanced antibacterial and osseointegrative capacity has great potential as an orthopedic/dental implant material for clinical application.

Clinical outcomes of personalized PEEK prosthesis in correcting nasolabial fold depression / 中华医学美学美容杂志

Objective:To investigate the clinical outcomes of personalized polyetheretherketone (PEEK) implant in the correction of nasolabial fold depression.Methods:A total of 30 patients with nasolabial fold depression (5 males, 25 females, aged 26 to 52 years, mean 36.3 years) admitted to the Affiliated Friendship Plastic Hospital of Nanjing Medical University who want to undergo nasolabial fold augmentation from January 2019 to January 2021. All patients underwent CBCT scan and three-dimensional simulation, the personalized PEEK implant was designed and produced with CAD/CAM technique, the personalized PEEK was implanted during the operation. The patients were followed up for 3-12 months, and the wrinkle score and satisfaction were compared before operation and 3 months and 6 months after operation.Results:The depressions of nasolabial fold were significantly improved in all patients, and there were no complications such as hematoma and infection after operation. During the follow-up, there was no implant displacement or exposure, and the effect was stable and lasting. The scores of wrinkles at 3 months after operation (2.30±0.47) and 6 months after operation (2.17±0.38) were significantly lower than those before operation (4.03±0.67), and the scores of satisfaction were significantly higher than those before operation ( P<0.05). The scores of satisfaction at 3 months after operation (3.97±0.56) and 6 months after operation (4.23±0.57) were significantly higher than those before operation (1.70±0.60). The difference was statistically significant ( P<0.05). Conclusions:3D printing personalized PEEK prosthesis is effective in correcting nasolabial fold depression, and it is safe and stable, so it is recommended for clinical application.

Flexural strength of polyether ether ketone high-performance polyether in comparison with base metal alloy and zirconia ceramic / Resistencia a la flexión del poliéter éter cetona poliéter de alto rendimiento en comparación con la aleación de metal base y la cerámica de circonio

Optimal flexural strength is a critical prerequisite for prosthetic frameworks. This study aimed to assess the flexural strength of polyether ether ketone (PEEK) polymer compared to a base metal alloy and high-strength Zirconia ceramic commonly used in prosthodontic treatments. Materials and Methods: In this in vitro, experimental study, 10 bar-shaped samples measuring 18×5×2mm were fabricated of each the PEEK polymer, nickel-chromium base metal alloy and zirconia ceramic. Half of the samples in each group were subjected to 5000 thermal cycles between 5°C - 55°C with 20 seconds of dwell time and 20 seconds of transfer time to simulate oral conditions. All samples then underwent three-point bending test. Two-way ANOVA followed by Tukey's test were applied to compare the mean flexural strength of the groups with and without thermocycling at 0.05 level of significance. Results: The flexural strength of base metal alloy, Zirconia and PEEK was 1387.70±45.50 MPa, 895.13±13.99 MPa and 192.10±5.37 MPa, respectively. The difference was significant among the groups (p<0.001). Thermocycling had no significant effect on the flexural strength of samples in any group (p=0.306). Conclusion: PEEK high-performance polymer had a lower flexural strength than base metal alloy and Zirconia ceramic, and its flexural strength was not affected by thermocycling. PEEK seems to be able to resist masticatory forces in the oral cavity pending further in vitro and clinical studies.

La resistencia a la flexión óptima es un requisito previo crítico para los marcos protésicos. Este estudio tuvo como objetivo evaluar la resistencia a la flexión del polímero de poliéter éter cetona (PEEK) en comparación con una aleación de metal base y cerámica de Zirconia de alta resistencia comúnmente utilizada en tratamientos de prostodoncia. Materiales and Métodos: En este estudio experimentalin vitro, se fabricaron 10 muestras en forma de barra de 18 × 5 × 2mm de cada polímero PEEK, aleación de metal base de níquel-cromo y cerámica de circonio. La mitad de las muestras en cada grupo fueron sometidas a 5000 ciclos térmicos entre 5°C - 55°C con 20 segundos de tiempo de permanencia y 20 segundos de tiempo de transferencia para simular condiciones orales. Todas las muestras se sometieron a una prueba de flexión de tres puntos. Se aplicó ANOVA bidireccional seguido de la prueba de Tukey para comparar la resistencia a la flexión media de los grupos con y sin termociclado a un nivel de significancia de 0.05. Resultados: La resistencia a la flexión de la aleación de metal base, Zirconia y PEEK fue de 1387,70 ± 45,50 MPa; 895,13 ± 13,99 MPa y 192.10 ± 5,37 MPa, respectivamente. La diferencia fue significativa entre los grupos (p<0,001). El termociclado no tuvo un efecto significativo sobre la resistencia a la flexión de las muestras en ningún grupo (p=0,306).Conclusión:El polímero de alto rendimiento PEEK tiene una resistencia a la flexión más baja que la aleación de metal base y la cerámica de circonio, y su resistencia a la flexión no se vio afectada por el termociclado. PEEK parece ser capaz de resistir las fuerzas masticatorias en la cavidad oral, con la necesidad de más estudios in vitroy clínicos.

Biocompatibility of bone marrow mesenchymal cells on polyetheretherketone and titanium surfaces in vitro / 口腔疾病防治

Objective@#To compare the in vitro biocompatibility of bone marrow mesenchymal cells on polyetheretherketone (PEEK) and titanium (Ti) surfaces.@*Methods @#PEEK and Ti foils with thicknesses of 1 mm and diameters of 10 mm were prepared. First, bone marrow mesenchymal cells were separated and purified by the whole bone marrow adherent culture method in vitro. Then, osteogenesis-induced bone marrow mesenchymal cells were cultivated on the surfaces of the PEEK and Ti foils. Scanning electron microscopy (SEM), the Alamar Blue test, an alkaline phosphatase (ALP) kit and Alizarin Red staining were used to analyze calcium nodules and compare the adhesion, proliferation and osteogenic differentiation ability of bone marrow mesenchymal cells on the surfaces of the PEEK and Ti foils.@*Results @# ① The morphology of the bone marrow mesenchymal cells cultured on the PEEK and Ti foils at 1 h, 4 h and 24 h showed no significant differences. ② In the 1 h, 3 h, 1 d and 3 d cultures of the bone marrow mesenchymal cells inoculated on the surfaces of the foils, the number of living cells in the PEEK group was greater than that in the Ti group (P < 0.05). ③ In the 7 d and 14 d osteogenesis-induced cultures of the inoculated bone marrow mesenchymal cells, the ALP activity of the PEEK group cells was significantly greater than that of the Ti group cells (P < 0.05). ④ Semiquantitative analysis after Alizarin Red staining showed that the mineralization degree of the bone marrow mesenchymal cells induced by osteoblasts was greater in the PEEK group than in the Ti group (P < 0.05). @*Conclusion@#PEEK has better in vitro biocompatibility than Ti and can better promote cell adhesion, proliferation and osteogenic differentiation compared with Ti, and so it is expected to become a new dental implant material.

A case of maxilla implant overdenture using Pekkton telescopic attachment with severe alveolar bone resorption / 대한치과보철학회지

It is necessary to set the correct occlusal plane and to distribute the occlusal force uniformly considering the state of the opposing dentition during the prosthetic of the single edentulous patient with severe alveolar bone resorption. Implant supported overdenture is superior to complete denture in terms of maintenance and stability, and limited implants are used in fully edentulous patients with high alveolar bone resorption. Telescopic attachments using a newly introduced material based on poly-aryl-ether-ketone (PAEK) have the advantages of typical telescopic copping, excellent abrasion resistance, and are lighter and more economical than conventional implant overdentures. In this case, we restored maxillary arch with a implant retained overdenture using the telescopic attachment made of Pekkton and the mandible was restored with fixed implant prosthesis. Through these procedures esthetic aspects and functional outcomes were satisfactorily achieved.

Three-Dimensional Finite Element Analysis of PEEK Customized Reconstruction Plate for Mandibular Defect / 医用生物力学

Objective To study the stress distributions of mandible defect by reconstruction with polyetheretherketone (PEEK) and its composite reconstruction plate through three-dimensional finite element analysis. Methods The finite element models of reconstruction plate of titanium alloy, PEEK, carbon-fiber-reinforced polyetheretherketone (CFR)-PEEK with 30% endless carbon fibers and CFR-PEEK with 68% endless carbon fibers were established by CBCT scanning，Mimics software，SolidWorks, Geomagic Studio and ANSYS Workbench software, and titanium alloy served as control. Two occlusal situations were simulated in the mandible model. Loading I: anterior region loading with 300 N; loading II: left posterior region with 300 N. Results The ratio of the maximum Von Mises stress of the reconstructed plate to its yield strength under two load situations: PEEK system ＞ 30%CFR-PEEK system ＞ titanium alloy system ＞ 68% CFR-PEEK system; the maximum stress of the mandible: PEEK system ＞ 30% CFR-PEEK system ＞ titanium alloy system ＞ 68% CFR-PEEK system. In the PEEK system, the maximum Von Mises stress of reconstructed plate and mandibular exceeded its yield strength under loading I; in the other systems, the maximum Von Mises stresses of mandible and reconstruction plate were below the yield strength. Conclusions The reconstruction plate of CFR-PEEK with 68% endless carbon fibers distributed the stresses in a similar manner as the titanium reconstruction plate, which could meet the mechanical strength requirements of mandible defect reconstruction. The fracture risk of the reconstructed plate was lower than that of titanium alloy, but the incidence of stress shielding was slightly higher. The result can provide references for the selection of materials and clinical application of reconstruction plate for mandibular defects.

Application of polyetheretherketone and its composite as frameworks in fixed dental prostheses / 中华口腔医学杂志

Characterized by eminent mechanical properties, chemical stability and biosafety, polyetheretherketone (PEEK), as a brand-new type of biomedical material, has been applied in the field of stomatology. This review elaborates on basic behaviors and fabrication methods of PEEK and its composite, and their application in fixed dental prostheses (FDP) as frameworks as well as their adhesive properties. Meanwhile, this review also looks into the prospect of the integration of additive manufacturing in fabricating frameworks of PEEK and its composite in FDP.

Effect of two kinds of surface pretreatments on bending strength to the modified polyetheretherketone / 华西口腔医学杂志

OBJECTIVE@#To evaluate the effect of sandblasting or acid etching on the three-point bending strength to the modified polyetheretherketone (PEEK).@*METHODS@#Forty-eight bars (15 mm×2 mm×1 mm) of specimens were fabricated from the modified PEEK (BioHPP). They were randomly divided into the following groups: A, B, C and D groups, which were blasted with alumina particles; E, F, and G groups, which were etched with 98% concentrated sulfuric acid; and control group H. The sand blast pressure of groups A, B and C was 0.2 MPa, and the grain sizes of the sand blasted were 120, 50, and 250 µm, respectively. Group D was blasted with 120 µm particle size at 0.7 MPa pressure. Groups E, F and G were acid etched for 60, 120, and 300 s, respectively. No surface treatment was conducted in group H. After all the specimens were processed, one sample was randomly selected from each group to observe its surface morphology under a scanning electron microscope (SEM), and the other specimens were tested for their three-point bending strength. SPSS 22.0 software was used to analyze the experimental data and to test whether the difference was statistically significant.@*RESULTS@#SEM observation showed that the surface morphology of the specimen changed after the treatment and revealed different degrees of cracks, pits, or voids. The three-point bending test indicated that the strength of the specimens treated with sandblasting or concentrated sulfuric acid decreased compared with that of the control group (P0.05). The strength of group D was lower than that of group A at the same particle size (P0.05).@*CONCLUSIONS@#The bending strength of BioHPP could be significantly decreased by surface sand blasting or concentrated sulfate etching as the sandblasting pressure increased, but the bending strength did not decrease as sand particle size and acid etching time changed.

The influence of different chemical treatments on the surface modification and biological behavior of PEEK / 实用口腔医学杂志

Objective: To improve the bioactivity of PEEK by chemical methods. Methods: PEEK samples were treated by polish only (group (1)) ; concentrated sulfuric acid for 5 min (group (2)) ; concentrated sulfuric acid for 10 min (group (3)) ; concentrated sulfuric acid for 5 min, followed by treatment of hydrogen nitrate for 5 min (group (4)) and mineral chameleon and ortho-phosphoric acid (group (5)) respectively (n = 9) . Then, all samples were treated by water at 100 ℃ for 4 h. The sample surface was observed by FE-SEM, the chemical comporent of the samples was analyzed by XPS. BMSCs were cultured on the sample surface for 4 h and observed by SEM. Results: The sample sureface in group (1) was smooth, in group (2), (3) and (4) was with 3 D ethmoidal foramen structure, in group (5) with petal-like from. The sulfur content (Wt％) of the samples of group (1), (2), (3), (4) and (5) was 0, 2. 45 ± 0. 22, 3. 48 ± 0. 16 (vs (1), P= 0. 000), 1. 79 ± 0. 05 (vs (1) P = 0. 002) and 0 respectively. BMSCs cultured on the sample surface of group (2), (3), (4) and (5) were more and with more pseudopod. Conclusion: The bioactivity of PEEK can be enhanced after acid pickling. Water bath and nitric acid treatment can remove the residual acid and further enhance the bioactivity of PEEK.

Early Fusion Status after Posterior Lumbar Interbody Fusion with Cortical Bone Trajectory Screw Fixation: A Comparison of Titanium-Coated Polyetheretherketone Cages and Carbon Polyetheretherketone Cages

STUDY DESIGN: Retrospective cohort study. PURPOSE: We recently reported that when compared to posterior lumbar interbody fusion (PLIF) using traditional pedicle screw fixation, PLIF with cortical bone trajectory screw fixation (CBT-PLIF) provided favorable clinical outcomes and reduced the incidence of symptomatic adjacent segment pathology, but resulted in relatively lower fusion rates. Since titanium-coated polyetheretherketone (PEEK) cages (TP) could improve and accelerate fusion status after CBT-PLIF, early fusion status was compared between CBT-PLIF using TP and carbon PEEK cages (CP). OVERVIEW OF LITERATURE: A systematic review demonstrated that clinical studies at this early stage show similar fusion rates for TP compared to PEEK cages. METHODS: We studied 36 consecutive patients undergoing CBT-PLIF with TP (TP group) and 92 undergoing CBT-PLIF with CP (CP group). On multiplanar reconstruction computed tomography (MPR-CT) at 6 months postoperatively, vertebral endplate cysts (cyst signs) were evaluated and classified as diffuse or local cysts. Early fusion status was assessed by dynamic plain radiographs and MPR-CT at 1 year postoperatively. RESULTS: The incidences of cyst signs, diffuse cysts, and early fusion rate in the TP and CP groups were 38.9% and 66.3% (p0.05), respectively. Combining the two groups, 22 of 36 patients with diffuse cysts had nonunion at 1-year follow-up, compared to only three of 92 patients with local cysts or without cyst signs (p<0.01). CONCLUSIONS: Despite having fewer patients with endplate cysts at 6 months (a known risk factor for nonunion), the TP group had the same fusion rate as the CP group at 1-year follow-up. Thus, TP did not accelerate the fusion process after CBT-PLIF.

Effects of body-shade resin layer thickness on the color of polyetheretherketone-Crea.lign restorations / 华西口腔医学杂志

OBJECTIVE@#This study aims to assess the effects of the different thicknesses of body-shade resin layers on the color of polyetheretherketone (PEEK)-Crea.lign restorations.@*METHODS@#Five PEEK specimens with the thickness of 0.6 mm were prepared. The color values of PEEK specimens were measured. Afterward, opaque-shade resin layers (0.1 mm) and body-shade resin layers (1.5 mm) were stacked with mold. The five specimens were evenly ground to a thickness of 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.2, and 0.0 mm in sequence. After grinding and ultrasonic cleaning, the color value was measured.@*RESULTS@#With the constant thickness of PEEK and 0.1 mm thickness of opaque-shade resin layer, the L*, a*, and b* values all showed downward trend with the increased thickness of the body-shade resin layer (1.0-1.4 mm). With the constant thickness of PEEK and 0.1 mm thickness of opaque-shade resin layer, the color difference between the adjacent groups was less than 1.5 NBS. This difference between nonadjacent groups was more than 1.5 NBS when the thickness of the body-shade resin layer reached 0.6 mm. Color difference between PEEK-Crea.lign restoration and PEEK was more than 1.5 NBS.@*CONCLUSIONS@#The thickness change in the body-shade resin layers influence the color of the PEEK-Crea.lign restorations. Using A2 shade Crea.lign, opaque-shade resin layer thickness is 0.1 and 0.6 mm thickness of body-shade resin layer can produce color which clinically acceptable.

Outcomes of Anterior Cervical Fusion Using Polyetheretherketone Cage with Demineralized Bone Matrix and Plate for Management of Subaxial Cervical Spine Injuries / 대한신경손상학회지

OBJECTIVE: We evaluated the usefulness of a polyetheretherketone (PEEK) cage filled with demineralized bone matrix (DBM) and plate fixation in anterior interbody fusions for subaxial cervical spine injuries. METHODS: A retrospective review of 98 patients (58 women, 40 men; mean age, 49.7 years; range, 17–78 years) who underwent single-level anterior cervical discectomy and fusion (ACDF) using a PEEK cage filled with DBM and plate fixation for subaxial cervical spine injuries from March 2005 to June 2018 was conducted. Bone fusion, interbody height (IBH), segmental lordosis, and adjacent segment degeneration (ASD) development were assessed with plain radiographs and computed tomography. Clinical outcomes were assessed using a visual analog scale (VAS) for pain and the Frankel grade for neurologic function. RESULTS: The mean follow-up period was 27.6 months (range, 6–142 months). Twenty-one patients (21.4%) had an improvement of at least one Frankel grade. The mean preoperative and final follow-up neck pain VAS scores were 8.3±0.9 and 2.6±1.5 (p < 0.05). All patients showed solid fusion at the final follow-up. The mean preoperative and final Cobb's angles were −3.7±7.9° and 1.9±5.1° (p < 0.05). The mean preoperative and final IBHs were 36.9±1.7 mm and 38.2±1.8 mm (p < 0.05). Five patients (5%) showed ASD. CONCLUSION: ACDF using a PEEK cage filled with DBM and plate fixation yielded high fusion rates and satisfactory clinical outcomes without donor-site morbidity. This procedure is safe and effective for single-level subaxial cervical spine injuries.