Simvastatin delivery on PEEK for bioactivity and osteogenesis enhancements

Abstract

A strategy developed for obtaining positive cellular responses remains to be focused in the filed of functional biomimetics. In this study, a hydrogel covered simvastatin-loaded polyetheretherketone (PEEK) bio-composites was constructed with the purpose of bone tissue regeneration therapy. Briefly, a three-dimensional (3D) porous structure was fabricated on PEEK surface; then the substrate was functionalized with the poly(L-lactic acid)/simvastatin porous film and hyaluronic acid hydrogel subsequently. In vitro cell attachment, proliferation, and cytoskeletal observation experiments reveal that our scaffolds show better bio-affinity due to the layer of hyaluronic acid hydrogel compared with control. Furthermore, the alkaline phosphatase activity, calcium mineral deposition evaluation, and gene expression for osteogenic potential all exhibit that the superior osteogenic differentiation of MC3T3-E1 pre-osteoblasts on our scaffolds. Therefore, our PEEK samples loaded with simvastatin and covered with hyaluronic acid hydrogel hold great potential in clinical applications for bone repair.     

Adhesion to high-performance polymers applied in dentistry: A systematic review

ObjectiveThe aim of this systemic review, conducted in accordance with the PRISMA statement, was to investigate the impact of surface pretreatments on the bonding strength of high performance polymers (HPPs).MethodsEight databases were searched through March 2019. Risk of bias was assessed and random effects meta-analyses were applied to analyze mean differences in shear bond strength (SBS) and tensile bond strength (TBS), considering surface pretreatments and bonding agents after 24h and thermocycling.ResultsA total of 235 relevant titles and abstracts were found, yielding 11 final selections. Low risk of bias was observed in most studies. For polyetheretherketone (PEEK) specimens, random-effect models showed that, compared to non-treated controls, pretreatments associated with Visio.link® (Bredent, Senden, GE) increased TBS by 26.72 MPa (95% confidence interval (CI), 19.69–33.76; p < 0.00001) and increased SBS by 4.86 MPa (95% CI, 2.61–7.10; p < 0.00001). Air abrasion improved SBS by 4.90 MPa (95% CI, 3.90–5.90; p < 0.00001) (50 μm alumina) and 4.51 MPa (95% CI, 1.85–7.18; p = 0.0009) (silica-coated CoJet). In comparison to non-treated controls, Visio.link® and Signum PEEK Bond® (Heraeus Kulzer, Hanau, GE) increased SBS by 33.76 MPa (95% CI, 18.72–48.81; p < 0.00001) and 33.28 MPa (95% CI, 17.48–49.07; p < 0.00001), respectively. No differences were found between Visio.link® and Signum PEEK Bond® or Monobond Plus/Heliobond® (Ivoclar Vivadent, Schaan, LH) (p > 0.05). Similar results were observed for polyetherketoneketone (PEKK) specimens.SignificanceThis review shows improved HPP bonding following the application of various surface pretreatments, including air abrasion and bonding agents.     

Comparison of oral micro-adhesion on polyetheretherketone,zirconium dioxide,and pure titanium abutment北大核心

BACKGROUND: There are some aesthetic and biomechanical problems in the application of zirconium dioxide and pure titanium abutment in the anterior teeth area. A kind of aesthetic abutment material conforming to biomechanics needs to be studied urgently. OBJECTIVE: To compare the adhesion of Porphyromonas gingivalis and whole saliva on the surface of polyetheretherketone (PEEK), zirconium dioxide (ZrO2), and pure titanium (Ti). METHODS: Specimens with the shape of a disk were prepared from PEEK, ZrO2, and Ti. The surface morphology feature was observed by scanning electron microscope. Surface roughness was determined by atomic force microscope. Contact angle was measured using contact angle measuring instrument. The adhesion force of Porphyromonas gingivalis on the surface of materials was measured using an atomic force microscope probe. The initial bacterial adhesion on materials in the suspension of Porphyromonas gingivalis and whole saliva was evaluated by scanning electron microscope and Cell Counting Kit-8 assay. RESULTS AND CONCLUSION: (1) Scanning electron microscope showed that the surface of the PEEK and Ti specimen was grooved, and the groove of PEEK was more than that of Ti, and there were a few microholes on the surface of ZrO2. Atomic force microscopy showed that parallel groove undulations were observed on the surfaces of the three specimens. The groove peak and valley structure of PEEK and ZrO2 was more prominent than that of Ti, and the porous concave and convex structure of the ZrO2 surface was more than that of PEEK. (2) The surface roughness of ZrO2 was greater than that of Ti (P < 0.05). The pairwise comparison between other groups showed no significant difference (P > 0.05). There was no significant difference between the contact angles of the three groups (P > 0.05). (3) A significantly lower adhesion force was identified for PEEK than for ZrO2 and Ti (P < 0.05). (4) The results of scanning electron microscope observation showed that the bacterial adhesion on the PEEK surface was the least, while that on the Ti surface was the most. The Cell Counting Kit-8 assay result showed that the initial bacterial adhesion on the surface of PEEK was significantly lower than that on the surface of ZrO2 and Ti (P < 0.05). (5) The results suggest that PEEK has more advantages to inhibit initial bacterial adhesion than conventional abutment materials such as ZrO2 and Ti. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Transforaminal lumbar interbody fusion using unilateral pedicle screws and a translaminar screw

Lumbar spinal fusion is advancing with minimally invasive techniques, bone graft alternatives, and new implants. This has resulted in significant reductions of operative time, duration of hospitalization, and higher success in fusion rates. However, costs have increased as many new technologies are expensive. This study was carried out to investigate the clinical outcomes and fusion rates of a low implant load construct of unilateral pedicle screws and a translaminar screw in transforaminal lumbar interbody fusion (TLIF) which reduced the cost of the posterior implants by almost 50%. Nineteen consecutive patients who underwent single level TLIF with this construct were included in the study. Sixteen patients had a TLIF allograft interbody spacer placed, while in three a polyetheretherketone (PEEK) cage was used. Follow-up ranged from 15 to 54 months with a mean of 32 months. A clinical and radiographic evaluation was carried out preoperatively and at multiple time points following surgery. An overall improvement in Oswestry scores and visual analogue scales for leg and back pain (VAS) was observed. Three patients underwent revision surgery due to recurrence of back pain. All patients showed radiographic evidence of fusion from 9 to 26 months (mean 19) following surgery. This study suggests that unilateral pedicle screws and a contralateral translaminar screw are a cheaper and viable option for single level lumbar fusion.     

Enhanced osteointegration on tantalum-implanted polyetheretherketone surface with bone-like elastic modulus

Polyetheretherketone (PEEK) possesses a similar elastic modulus as bones but yet suffers from bio-inertness and poor osteogenesis. In this work, tantalum ions are implanted energetically into PEEK by plasma immersion ion implantation (PIII) to form Ta₂O₅ nanoparticles in the near surface. Nanoindentation reveals that the surface elastic modulus of the Ta ion implanted PEEK is closer to that of human cortical bones. In vitro cell adhesion, alkaline phosphatase activity, collagen secretion, extracellular matrix mineralization, and real-time PCR analyses disclose enhanced adhesion, proliferation, and osteogenic differentiation of rat bone mesenchymal stem cells (bMSCs) on the Ta-PIII modified PEEK. In vivo evaluation of the cortico-cancellous rat femur model by means of micro-CT, sequential fluorescent labeling, and histological analysis after 8 weeks confirms significantly improved osteointegration. The bone-like elastic modulus and modified surface topography of the Ta-PIII modified PEEK synergistically induce osteogenic differentiation of bMSCs and the surface-modified materials have large potential in dental and orthopedic implants.     

钛金属cage与聚醚醚酮cage在颈前路减压融合术后临床疗效的Meta分析

目的 采用Meta分析比较钛金属cage与聚醚醚酮(PEEK)cage在颈前路减压椎间融合术(ACDF)中的临床效果,为ACDF植入物的选择提供临床依据。方法 计算机检索PubMed数据库、Cochrane数据库、Embase数据库、中国知网数据库、万方数据库,并辅以手工检索,收集2007年1月—2017年3月有关钛金属cage和PEEK cage 用于ACDF临床效果对照研究的中英文文献,按照Jadad量表严格评价纳入文献质量,并提取相关数据,运用Revman 5.0软件对所有相关数据进行分析。结果 纳入5项研究共361例患者,其中高质量文献4篇,中质量文献1篇。Meta分析显示对于ACDF,PEEK cage下沉发生率低于钛金属cage(OR=3.49,95%CI 1.75~6.99,P=0.0004),而在融合率(OR=1.60,95%CI 0.05~53.73,P=0.79)、脱位发生率(OR=3.61,95%CI 0.91~14.34,P=0.07)、手术时间(WMD=0.87,95%CI -24.95~26.69,P=0.95)、Odom评分优良率(OR=0.89,95%CI 0.49~1.63,P=0.71)、NDI评分(WMD=3.24,95%CI -0.44~6.93,P=0.08)及手术节段术后Cobb角(WMD=-2.29,95%CI -4.63~0.05,P=0.05)等方面两种cage差异无统计学意义。结论 钛金属cage和PEEK cage 应用于ACDF均能获得理想的临床效果,术后PEEK cage下沉发生率更低。     

Cranioplasty with patient-specific implants in repeatedly reconstructed cases

Objective

Cranioplasty is indicated to restore form and function of bone defects of the neurocranium. Autografts are the gold standard, alloplastic materials are used when autologous bone is unavailable or unsuitable, and increasing evidence supports the use of patient-specific implants (PSIs) for reconstruction. We reviewed our own patient data to assess pre- and intraoperative aspects, complications and costs in patients that were treated with PSIs from titanium or polyetheretherketone (PEEK) for skull bone reconstruction.

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

ObjectiveThe objective of this study was to determine the effect of two plasma surface treatments on the biologic responses of PEEK medical implants manufactured by fused filament fabrication (FFF) 3D printing technology.MethodsThis study created standard PEEK samples using an FFF 3D printer. After fabrication, half of the samples were polished to simulate a smooth PEEK surface. Then, argon (Ar) or oxygen (O₂) plasma was used to modify the bioactivity of FFF 3D printed and polished PEEK samples. Scanning electron microscopy (SEM) and a profilometer were used to determine the microstructure and roughness of the sample surfaces. The wettability of the sample surface was assessed using a drop shape analyzer (DSA) after plasma treatment and at various time points following storage in a closed environment. Cell adhesion, metabolic activity, proliferation, and osteogenic differentiation of SAOS-2 osteoblasts were evaluated to determine the in vitro osteogenic activity.ResultsSEM analysis revealed that several spherical nanoscale particles and humps appeared on sample surfaces following plasma treatment. The wettability measurement demonstrated that plasma surface treatment significantly increased the surface hydrophilicity of PEEK samples, with only a slight aging effect found after 21 days. Cell adhesion, spreading, proliferation, and differentiation of SAOS-2 osteoblasts were also up-regulated after plasma treatment. Additionally, PEEK samples treated with O₂ plasma demonstrated a higher degree of bioactivation than those treated with Ar.SignificancePlasma-modified PEEK based on FFF 3D printing technology was a feasible and prospective bone grafting material for bone/dental implants.     

不同表面处理方式对聚醚醚酮与复合树脂粘接性能的影响

目的研究不同存储条件下6种通用型粘接剂及喷砂条件对聚醚醚酮（PEEK）与复合树脂之间粘接强度和耐久性的影响。 方法将PEEK材料切割成12个边长为2 cm的正方体试件。对其中6个试件进行氧化铝喷砂处理。6种通用型粘接剂为：Tetric N-Bond Universal（TNU）、Single Bond Universal（SBU）、DX.BOND UNI（DXB）、Selective Etch Bond（SEB）、Gluma Bond Universal（GBU）、Prime & Bond Universal（PBU）。实验分为7组,每组包含4个喷砂面和4个未喷砂面。7种表面处理方法分别为：不使用粘接剂（对照组）和6种通用型粘接剂（实验组：TNU组、SBU组、DXB组、SEB组、GBU组、PBU组）。经表面处理后,将流动复合树脂F00注入透明模具并将其无压力置于试件表面后进行光照固化。试件分别在37 ℃恒温水浴24 h或冷热循环3000次后进行剪切粘接强度测试。使用松风EyeSpecial C-Ⅳ口腔专用相机微距模式进行断面拍照并进行断裂模式分析。采用SPSS 23.0软件Three-Way ANOVA（冷热循环、粘接剂与喷砂）与Tukey方法对各组数据进行统计分析（α = 0.05）。 结果24 h水浴条件下,TNU组分别获得不喷砂组（9.92 ± 1.19）MPa与喷砂组（9.97 ± 1.03）MPa最高粘接强度;冷热循环3000次后PBU组分别获得不喷砂组（6.75 ± 0.99）MPa与喷砂组（7.22 ± 1.30）MPa最高粘接强度。三因素分析结果显示：冷热循环（F = 3 045.429,P<0.001）、粘接剂（F = 361.165,P<0.001）与喷砂（F = 80.050,P<0.001）可显著影响粘接强度;冷热循环与粘接剂（F = 155.724,P<0.001）、粘接剂与喷砂（F = 3.535,P = 0.002）、冷热循环与喷砂（F = 9.184,P = 0.003）两两因素间分别具有交互作用;冷热循环、粘接剂与喷砂三因素间具有交互作用（F = 12.392,P<0.001）。 结论（1）喷砂有助于改善通用型粘接剂对复合树脂与PEEK 37 ℃恒温水浴24 h粘接强度;（2）复合树脂与PEEK粘接强度在冷热循环3000次后显著降低;（3）本实验中PBU组粘接耐久性优于其他粘接系统。     

The effect of thermo-mechanical fatigue on the retentive force and dimensional changes in polyetheretherketone clasps with different thickness and undercut

PURPOSEEsthetic expectations have increased the use of polyetheretherketone (PEEK) clasps as alternatives to Cr-Co in removable partial dentures (RPDs). The objective of this study was to evaluate the retentive force and dimensional change of clasps with different thickness and undercut made from PEEK by the thermo-mechanical fatigue.MATERIALS AND METHODSPEEK clasps (N = 48) with thicknesses of 1 or 1.50 mm and 48 premolar monolithic zirconia crowns with undercuts of 0.25 mm or 0.50 mm were fabricated. Samples are divided into four groups (C1-C4) and were subjected to 7200 thermal aging cycles (at 5 - 55℃). The changes in the retentive force and dimensions of the clasps were measured by micro-stress testing and micro-CT devices from five measurement points (M1 - M5). One-way ANOVA, paired t-test, two-way repeated ANOVA, and post-hoc tests were used to analyze the data (P < .05).RESULTSThe retentive forces of C1, C2, C3, and C4 groups in initial and final test were found to be 4.389-3.388 N, 4.67 - 3.396 N, 5.161 - 4.096 N, 5.459 - 4.141 N, respectively. The effects of retentive force of all PEEK clasps groups were significant decreased. Thermo-mechanical cycles caused significant dimensional changes at points with M2, M4, and M5, and abraded the clasp corners and increased the distance between the ends of the clasp, resulting in reduced retentive forces (P^* = .016, P^* = .042, P < .001, respectively).CONCLUSIONThermo-mechanical aging decreases the retentive forces in PEEK clasps. Increasing the thickness and undercut amount of clasps decreases the amount of dimensional change. The values measured after aging are within the clinically acceptable limits.