Value of 3D printed polyether ether ketone prosthesis in the treatment of scapular tumors / 中华骨科杂志

Polyetheretherketone (PEEK) as a new type of thermoplastic engineering plastic, has good biological activity, elastic modulus close to human cortical bone and radiation permeability, and has been widely used in medical field. This study aims to explore the safety and clinical efficacy of using 3D printing personalized PEEK materials to repaire scapular bone defects after bone tumor resection. A total of 6 patients who underwent the implantation of 3D printed PEEK scapular prosthesis from January 2020 to December 2021 in Yunnan Cancer Hospital were retrospectively analyzed. There were 3 males and 3 females, with age ranged from 14 to 52 years. There were 1 case of synovial sarcoma, 1 of Ewing's sarcoma, and 4 of chondrosarcoma. PEEK prosthesis was designed and fabricated based on CT data before surgery. Tumor resection and prosthesis replacement were performed under the premise of ensuring safe surgical boundaries, including 2 cases of total scapular prosthesis replacement and 4 cases of partial scapular prosthesis replacement. The operation time was 90-170 min, and the intraoperative blood loss was 100-400 ml. All 6 patients received satisfactory follow-up, with a tumor progression free survival time of 16-28 months. No tumor recurrence or metastasis was observed, and all patients survived tumor free. At last follow-up, the Constant-Murley shoulder joint score was a minimum of 62 points and a maximum of 68 points. The Japanese Orthopaedic Association's shoulder joint score was 63 points minimum and 78 points maximum. Computer-aided design 3D printing PEEK material prosthesis has certain advantages in the treatment of scapular tumor limb salvage. It has light weight, well adapted, relatively simple installation, good histocompatibility, and can obtain a better appearance and function of the shoulder joint after operation. It can become one of the options for limb salvage treatment of scapular tumor.

Effects of concentrated sulfuric acid etching durations on the shear bond strength between polyether-ketone-ketone and dentin / 口腔疾病防治

Objective@# To study the effects of different concentrated sulfuric acid etching durations on the shear bond strength between polyether-ketone-ketone (PEKK) and dentin, providing a scientific basis for the clinical bonding procedures of PEKK prosthesis.@*Methods@# Forty-four PEKK specimens were prepared and randomly divided into four groups: group A was the control group, which was only polished with abrasive papers, group B, group C and group D were experimental groups, which were etched by 98% concentrated sulfuric acid for 5 s, 30 s and 60 s, respectively. In addition, one sample was randomly selected from each group, and the profile was prepared by a slow cutting machine. The surface morphology of the profile was observed under SEM. After the four groups of specimens and dentin were bonded by resin, they were soaked in distilled water at 37 ℃ for 24 h. After the shear bonding strengths were measured, the fracture interfaces of the specimens were examined by the scanning electron microscopy and stereomicroscopy, and failure models of bonding were analyzed. @*Results@#After acid etching treatments, the cross-sectional images in group B presented uniform spongy shapes, while the cross-sectional images in group C and group D showed destructive pore structures. The shear bond strengths of group B (16.84 ± 1.84) MPa, group C (12.33 ± 1.22) MPa and group D (6.44 ± 1.18) MPa were higher than that of group A (3.99 ± 1.06) MPa (P < 0.05). The highest shear bond strength was observed in group B (16.84 ± 1.84) MPa. @*Conclusion @#The surface treatment of 98% sulfuric acid etching for 5 s manifested the best bond strength between PEKK and dentin.

Comparative study of some mechanical properties of cobalt chromium and polyether ether ketone thermoplastic removable partial denture clasps: an In-vitro Study / Estudo comparativo de algumas propriedades mecânicas dos grampos parciais removíveis termoplásticos removíveis termoplásticos de cobalto cromo e éter cetona: um estudo in vitro

Objective: was to evaluate the retentive force, fatigue resistance and deformity of clasps made from two materials cobalt chromium and poly ether ether ketone (PEEK). Material and Methods: sixteen models were fabricated,each one having lower 1st molar. Models were divided into two groups according to materials,group I (GI) for cobalt chromium (Co-Cr) and group II (GII) for PEEK. Each testing models and its clasps were mounted inside universal testing machine, the retention was measured by applying withdrawal force to it by this machine at 5 mm/min. The Fatigue resistance is measured by the reduction in retention through repeated insertion and removal cycles using robota chewing simulator. Removal and insertion cycling of clasps was carried out for 360, 730, 1080, 1,440, 2,116 and 2,880 cycles (corresponding to 3, 6, 9, 12, 18 and 24 months of simulated clinical use of a RPD) to simulate the fatigue resistance test. Deformity was measured before and after each cycling using a digital micrometer. Statistical analysis was done by 2-way-ANOVA test to detect significance effects of each variable. Results: Retention and fatigue resistance, after 360, 730, 1080, 1,440, 2,116 and 2,880 cycles totally the difference between Co-Cr and PEEK groups was statistically non-significant (P = 0.0980> 0.05) where (Co-Cr > PEEK). Deformation results, regardless to evaluation time, Co-Cr group recorded statistically significant higher deformation mean value than PEEK group (P = 0.008 < 0.05).Regardless to material group, deformation mean value changed nonsignificantly by time (P = 0.2882> 0.05). Conclusion: PEEK clasps (1.0 mm in cross section diameter) engage 0.50 mm undercut provide sufficient retention nearly similar that of Co-Cr clasps.(AU)

Objetivo: o objetivo foi avaliar a força de retenção, a resistência à fadiga e a deformidade dos grampos fabricados com dois materiais diferentes: cromo-cobalto (Co-Cr) e poliéter-éter-étercetona (PEEK). Materiais e métodos: dezesseis modelos foram confeccionados, cada um com 1º molar inferior. Os modelos foram divididos em dois grupos de acordo com o material: grupo I Co-Cr e grupo II para PEEK. Cada modelo de teste universal e seus grampos foram montados em uma máquina de teste universal. A retenção foi medida aplicando força de retirada por esta máquina a 5 mm/min. A resistência à fadiga foi medida pela redução na retenção através de ciclos repetidos de inserção e remoção usando um simulador do ciclo de mastigação. O ciclo de remoção e inserção dos grampos foi realizado por 360, 730, 1080, 1.440, 2.116 e 2.880 ciclos (correspondendo a 3, 6, 9, 12, 18 e 24 meses de uso clínico simulado de um RPD) para simular o teste de resistência à fadiga. A deformidade foi medida antes e após cada ciclo, usando um micrômetro digital. A análise estatística foi realizada pelo teste ANOVA de 2 fatores para detectar os efeitos de significância de cada variável. Resultados: A retenção e a resistência à fadiga após 360, 730, 1080, 1.440, 2.116 e 2.880 ciclos entre os grupos Co-Cr e PEEK não mostrou diferença estatisticamente significativa (p = 0,0980> 0,05), onde (Co-Cr> PEEK). Para os resultados da deformação, independentemente do tempo de avaliação, o grupo Co-Cr registrou um valor médio de deformação maior, com diferença estatística significativa, quando comparado com o grupo PEEK (p= 0,008 < 0,05). Independentemente do grupo de material, o valor médio da deformação foi alterado de forma não significativa pelo tempo (p= 0,2882> 0,05). Conclusão: os grampos PEEK (1,0 mm de diâmetro da seção transversal) engatam 0,50 mm retenção quase semelhante à dos grampos Co-Cr (AU)

Comparing different bar materials for mandibular implant-supported overdenture: Finite-element analysis

Aim: This study was conducted aiming to optimize the selection of bar material that can minimize stresses on mandibular bone. Subjects and Methods: One finite-element model was created under ANSYS environment to evaluate the use of different materials as a bar-manufacturing material in mandibular implant-supported overdenture (OD). Model components were created on engineering computer-aided design software and then assembled under the finite-element package. A force of 200 N was unilaterally and vertically applied on the left second premolar area. Results: Within these study conditions, the polyether ether ketone bar produced the lowest Von Mises stress on OD and the maximum value of deformation. Stainless steel bar produced the maximum OD total deformation. Conclusions: Cortical and spongy bones are not sensitive to the bar material. Increasing bar material stiffness increases Von Mises stresses in the bar itself and reduces its total deformation, in what is called overconstrained system.

Observation of stand-alone MC+polyether-ether-ketone (PEEK) Cage in anterior cervical double-level fusion for more than 2 years follow-up / 中国修复重建外科杂志

Objective: To investigate the effectiveness of stand-alone MC+polyether-ether-ketone (PEEK) Cage (single blade type) in anterior cervical double-level fusion for more than 2 years follow-up. Methods: A clinical data of 30 patients who were treated with anterior cervical fusion surgery with stand-alone MC+PEEK Cage (single blade type) between January 2013 and December 2016 and followed up for more than 2 years, was retrospectively analyzed. There were 16 males and 14 females, aged from 34 to 72 years with an average of 52.2 years. There were 16 cases of cervical spondylotic myelopathy, 8 cases of cervical spondylotic myelopathy, and 6 cases of traumatic cervical disc herniation. The continuous double segments were C 4, 5, C 5, 6 in 12 cases and C 5, 6, C 6, 7 in 18 cases; and the disease duration ranged from3 days to 24 months (mean, 12 months). Postoperative neck hematoma and wound healing were observed; dysphagia was assessed by Bazaz system; and bone fusion was assessed by Suk method. Before operation, at 1 week after operation, and at last follow-up, the Japanese Orthopaedic Association (JOA) score was used to evaluate the neurological recovery; the cervical X-ray film was performed to record the cervical curvature (C 2-C 7 Cobb angle), the height of the intervertebral space of the fusion segment, and to judge the occurrence of the fusion Cage subsidence. Results: No complication such as neck hematoma, incision infection, or esophageal fistula was found, primary healing of incisions was obtained in all cases. All patients were followed up 24-72 months (mean, 46 months). Neurological symptoms such as limb numbness and pain gradually disappeared after operation; during the follow-up period, the cervical curvature could be effectively maintained; dysphagia and internal fixation related complications such as displacement of Cages were not found. All patients obtained bony fusion from 3 to 8 months with an average time of 4.3 months. Compared with preoperative ones, the JOA score, intervertebral space height, and Cobb angle of cervical spine were significantly improved at 1 week after operation and at last follow-up ( P0.05). Conclusion: The application of stand-alone MC+PEEK Cage (single card type) in anterior cervical fusion can provide early cervical stability, effectively maintain the physiological curvature of cervical spine and the height of fusion intervertebral space.

Performance of and Pressure Elevation Formed by Small-diameter Microtubes Used in Constant-flow Sets

PURPOSE: We explored the performance of and pressure elevation caused by small-diameter microtubes used to reduce overfiltration. METHODS: Using a syringe pump-driven constant-flow setting (2 µL/min), pressures were measured for polytetrafluoroethylene (PTFE) microtubes 5 mm in length with inner diameters of 51, 64, and 76 µm and for polyether block amide (PEBAX) microtubes with an inner diameter of 76 µm. Experiments (using microtubes only) were initially performed in air, water, and enucleated pig eyes and were repeated under the same conditions using intraluminal 9/0 nylon stents. RESULTS: The pressures measured in air in 51-, 64-, and 76-µm-diameter PTFE microtubes differed significantly (22.1, 16.9, and 12.2 mmHg, respectively; p < 0.001), and that of the 76-µm-diameter PEBAX microtube was 15.8 mmHg (p < 0.001 compared to the 12.2 mmHg of the 76-µm-diameter PTFE microtube). The pressures measured in water also differed significantly among the three microtubes at 3.9, 3.0, and 1.4 mmHg, respectively, while that in the PEBAX microtube was 2.6 mmHg (all p < 0.001). Using the intraluminal stent, the pressure in water of the three different PTFE microtubes increased to 22.6, 18.0, and 4.1 mmHg, respectively, and that in the PEBAX microtube increased to 10.5 mmHg (all p < 0.001). Similar trends were evident when measurements were performed in pig eyes. CONCLUSIONS: Although microtubes of smaller diameter experienced higher pressure in air, reduction of the inner diameter to 51 µm did not adequately increase the pressure attained in water or pig eyes. Insertion of an intraluminal stent effectively elevated the latter pressures. PEBAX microtubes created higher pressures than did PTFE microtubes.

Purification and Structure Elucidation of the Polyether Antibiotic Alborixin from Streptomyces pulcher CRF17.

Aims: To screen Streptomyces sp. from saline soil in Pakistan, for its antimicrobial activity and to purify and identify the active metabolites produced by mass spectrometry and NMR spectroscopy. Strain identification by morphological, biochemical, physiological characterization and by 16S rRNA gene sequencing. Study Design: Cultivation in lab fermenter, solvent extraction and purification of the compounds by column chromatography, identification of the compounds by mass spectrometry and NMR spectroscopy, determination of the antimicrobial activity and cytotoxicity. Place and Duration of Study: Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan and Institute of Organic and Bio molecular Chemistry, University of Göttingen, Germany, between February, 2007 and April, 2009. Methodology: The strain was cultivated in a 20 liter fermenter (working volume 10 liters) and the culture broth was extracted with ethyl acetate, acetone and methanol. The resultant crude extract was fractionated on silica gel and the components were purified by column chromatography (silica gel, sephadex column and preparative TLC). The pure component was identified by mass spectrometry (ESI and HRESI-MS), NMR analysis (1H and 13C NMR) and by comparison with reference data, the antimicrobial activity and cytotoxicity was determined by disc diffusion assay and by micro well cytotoxicity assay against Artimia salina. Results: The morphological, biochemical and physiological characterization suggested that isolate CRF17 belongs to the genus Streptomyces. Further NCBI BLAST of the partial 16S rDNA gene sequence 1420 bp (gene bank accession number: EU294134) from the isolate CRF17 showed 99% identity and 98% query coverage towards Streptomyces pulcher. The scale up fermentation of the isolate CRF17 yielded active compound and was identified as alborixin (1). Conclusion: The isolate Streptomyces pulcher CRF17 is a potent producer of the antibiotic alborexin and can be exploited for its commercial production.

F-01A, an antibiotic, inhibits lung cancer cells proliferation / 中国天然药物

AIM@#In an effort to identify novel, small molecules which can affect the proliferation of lung cancer cells, F-01A, a polyether antibiotic isolated from the fermentation broth of Streptomyces was tested.@*METHOD@#F-01A was tested for its antitumor properties on the lung cancer cell line SPC-A-1, at six doses (0.1, 0.5, 1, 2.5, and 5 μmol·L(-1)), using various cellular assays. Cell viability was measured by the MTT assay, Hochest 33258 was used to study nuclear morphology; DNA ladder and the loss of mitochondrial membrane potential were also evaluated.@*RESULTS@#F-01A induces apoptosis against SPC-A-1 cells in a dose-dependent manner. The IC50 is 0.65 μmol·L(-1), and the inhibition at 5 μmol·L(-1) is 87.89%. Further, JC-1 staining indicates F-01A could induce the loss of mitochondrial membrane potential, and the DNA fragment is evident.@*CONCLUSION@#Mechanistic analysis showed that F-01A induced apoptosis of cancer cells probably in the mitochondrial pathway. The antitumor actions of F-01A involve activation of the apoptotic pathway against SPC-A-1 cells, and it may be valuable for further drug development.

Comparative study to evaluate the accuracy of polyether occlusal bite registration material and occlusal registration wax as a guide for occlusal reduction during tooth preparation.

Introduction: The use of different materials and techniques has been studied to decide the safest quantum of reduction of the occlusal surfaces. However, these methods provide limited information as to the actual amount of reduction with limitations in accuracy, accessibility and complexity. Objective: The objective of this study was to compare and evaluate the reliability of the most commonly used occlusal registration wax that with polyether bite registration material as a guide for occlusal reduction required during tooth preparations. Materials and Methods: For the purpose of this study, 25 abutment teeth requiring tooth preparation for fixed prosthesis were selected and tooth preparations carried out. Modeling wax strips of specific dimensions were placed onto the cast of prepared tooth, which was mounted on maximum intercuspation on the articulator and the articulator was closed. The thickness of the wax registration was measured at three zones namely two functional cusps and central fossa. Similar measurements were made using the polyether bite registration material and prosthesis at the same zones. The data was tabulated and was subjected to statistical analysis using anova test and Tukey honestly significant difference test. Results: The differences in thickness between wax record and prosthesis by 0.1346 mm, whereas the difference between polyether and prosthesis was 0.02 mm with a P value of 0.042, which is statistically significant. This means that the wax record was 8.25% larger than the prosthesis while polyether was just 1.27% larger than the prosthesis. Conclusion: The clinical significance of the above analysis is that Ramitec polyether bite registration material is most suitable material when compared with commonly used modeling wax during the tooth preparation.

Clinical Application of Polyether Ester Urethane in Endonasal Dacryocystorhinostomy

PURPOSE: To evaluate the clinical effect of intraoperative application of polyether ester urethane (Nasopore(R)) in endonasal dacryocystorhinostomy. METHODS: Endonasal dacryocystorhinostomy was performed on 77 eyes diagnosed with nasolacrimal duct obstruction between January 2010 and February 2011. Nasopore(R) was applied to the newly-formed internal lacrimal opening in the experimental group (41 eyes), and vaseline gauze was applied in the control group (36 eyes). For the evaluation of clinical effects regarding postoperative adhesion and stenosis of the internal lacrimal opening, subjective symptom improvement, lacrimal irrigation tests, and endoscopic examinations were performed at 1 week, 2 weeks, 1 month, 3 months, and 6 months, postoperatively. RESULTS: In subjective symptom improvement and lacrimal irrigation tests, differences between the 2 groups were not statistically significant. In endoscopic findings, the Nasopore(R) group showed significantly lower severity of adhesion and stenosis of the internal lacrimal opening at 1 week, 2 weeks, and 1 month after operation (p < 0.05). CONCLUSIONS: Application of the Nasopore(R) may effectively reduce initial postoperative adhesion or stenosis of the internal lacrimal opening after endonasal dacryocystorhinostomy and has usefulness as an auxiliary method.

An evaluation of the time-dependent dimensional stability of elastomeric impression materials / 대한치과보철학회지

Statement of Problem: The accuracy and dimensional stability of elastomeric impression materials have been the subject of numerous investigation. Few studies have addressed the effect of changes in time on the dimensional stability of impression materials. Purpose: The purpose of this investigation was to evaluate the effects of elastomeric impression materials and storage time on dimensional stability. Materials and methods: A total of 75 impressions were made of epoxy resin dies mimicked prepared 3-unit fixed partial denture. The dies had 1 buccolingual, 1 mesiodistal and 1 occlusogingival lines and interpreped dot. Impression materials investigated included two polyether impression materials and three polyvinylsiloxane impression material. 15 specimens were made of each impression material and poured by type IV stone over times(30 minutes, 24 hours, 72 hours) after mixing; the same examiner measured each specimen 3 times at a magnification of 3.5*. All statistical tests were performed with the level of significance set at .05. Results: The results indicated that significant difference at any measuring point of stone dies of the polyvinylsiloxane and polyether impression materials when measurements at 30 minutes, 24hours, and 72 hours were compared; the length of measuring point increased significantly as time passed by. However, this result is not significant clinically. Analysis also showed significant differences at any measuring point when polyvinylsiloxane and polyether impression materials were compared and significant differences clinically. Conclusion: Under the conditions of this study, the shrinkage rate of the polyvinylsiloxane and polyether impression materials significantly increased as time passed by. The polyether impression materials showed higher shrinkage significantly, while the shrinkage rate of all five materials showed a significant time-dependent increase.

Research on process of polyurethane coating for self-expandable stent in medical use / 中国介入心脏病学杂志

Objective To improve the biocompatibility of the metallic stent used for interventional treatment. Methods Inner coatings, outer coatings and micro-porous coatings were made using the solution-injection method, and salt crystallite with demanded size was added in order to develop micro-porous coatings. Results The optical concentrations of polyurethane solution and of salt crystallite (for micro-porous coatings) were obtained, and the corresponding processes were developed. Conclusion The poly-coated stent retains its elasticity, and it become very convenient to develop stents carrying drugs. Its effects on animals ard under test.