Microstructure and dry wear properties of Ti-Nb alloys for dental prostheses

The microstructure and properties of a series of binary Ti-Nb alloys for dental prostheses with niobium contents ranging from 5% to 20% were investigated. The experimental results indicate that the crystal structure and morphology of Ti-Nb alloys are sensitive to their niobium contents. When Nb content is 5%, the acicular α crystal grain is observed. When Nb content is 10%, the coarse equiaxed crystal grain and the fine, acicular α crystal grain are observed. When Nb content is 15%, only the α equiaxed crystal grain is observed. When the alloy contains 20%Nb, the equiaxed and dendritic α crystal grain are observed. For Ti-Nb alloys, the increase of Nb content modifies the microstructure of Ti-Nb alloys significantly and decreases their compression elastic modulus, in which Ti-20Nb alloy shows the largest compression strength and Ti-5Nb alloy shows the best plasticity. The dry wear resistance of Ti-Nb alloys against Gr15 ball was investigated on CJS111A ball-disk wear instrument. For Ti-Nb alloys, Ti-10Nb alloy shows a smallest steady friction coefficient, Ti-5Nb alloy shows the smallest wear depth and best wear resistance, and Ti-15Nb alloy shows the largest wear depth and worst wear resistance. The phenomenon of furrow cut happens and furrows form during wear tests.

Neural prostheses for restoring functions lost after spinal cord injury

Spinal cord injury（SCI）is a debilitating condition that affects more than 2.5 million individuals worldwide（Thuret et al.,2006）.In addition to its devastating effects on the individual,this disease is a heavy burden to the society in terms of health care costs, which are estimated in billions of dollars annually in most developed countries （Cadotte and Fehlings, 2011）.

Preparation and Mechanical Performance of Blended Polyester/Silk Small Diameter Arterial Prostheses

Small diameter arterial prostheses were required to treat coronary and cerebrovascular arterial diseases. The diameters of the artificial blood vessels should match the diameters of the host arteries. Besides,the mechanical properties of the arterial prostheses should be strong enough to endure the forces in the body after implantation. In this study,silk and polyester were woven into small diameter arterial prostheses and the dimensional and mechanical properties,as well as the water permeability,were investigated. The woven samples had an inner diameter ranging from 3. 65 to 3. 94mm. The wall thickness of the samples ranged from 0. 26 to 0. 28mm. Compared with polytetrafiuoroethylene( ePTFE) commercial devices,whose probe bursting strength was measured to be 15. 64 N /mm2,the woven samples had superior strength values ranging from20. 53 to 28. 97 N /mm2. In addition,the radial compliance of the woven samples was found to lie between the ePTFE sample and the pig's carotid artery,and the water permeability of all the woven samples was less than 300 mL /( cm2·min) which indicated that these woven samples could be implanted without preclotting.

New Design of Textile Vascular Prostheses for the Reconstruction of Small Diameter Vascular Blood Vessels

The general object of research is to design new idea of the semi-biodegradable,multilayered vascular prosthesis used for the reconstruction of significantly small diameter vascular vessels( microreconstruction). The paper studies the selection of appropriate sterilization technique for resorbable tubular structures made of poly( L-lactide-co-glicolide)( PLAGA) and nonbiodegradable tubular structures made of polypropylene( PP). The designed grafts are characterized by the physical properties as well as mechanical properties according to ISO 7198 ∶ 1998 Standard.Moreover,the process of the grafts fabrication will be explained considering the stages affected the critical properties of the elaborated textile implants. The increase of PLAGA melt-electrospun tubular structures mechanical properties was observed due to the thermal stabilization use. The ethylene oxide( EO) and steam sterilization had a destructive effect on the designed PLAGA meltelectrospun tubular, fibrous structures, whereas the irradiation yielded in the changes in mechanical and physical properties on the acceptable level,taking into account the future clinical applications.

Binding mechanism of interface of porous coated titanium alloy prostheses

ＢｉｎｄｉｎｇｍｅｃｈａｎｉｓｍｏｆｉｎｔｅｒｆａｃｅｏｆｐｏｒｏｕｓｃｏａｔｅｄｔｉｔａｎｉｕｍａｌｌｏｙｐｒｏｓｔｈｅｓｅｓＺｏｕＨｏｎｇｅｎ（邹宏思）；ＹｅＪｕｎ（叶军）；ＴａｎｇＮｏｎｇｘｕａｎ（唐农轩）；ＹｕａｎＣｕｎｈｕａ（袁存华）（Ｄｅ...

Comparison of the Radial Compliance of Three Kinds of Vascular Prostheses and Pig′s Carotid Based on Dynamic-simulated Condition

There are some problems in the vascular prostheses, which influence the health of the patients. This paper aims to the radial compliance of three kinds of vascular prostheses and the pig's carotid based on the dynamic-simulated condition. The radial compliance of knitted structure vascular prostheses with crimps ranged from 2.52% to 0.94%/100 mmHg, which was superior to e-PTFE and woven prostheses', ranged from 0.73% to 0.31%/100 mmHg and from 0.81% to 0.22%/100 mmHg. But comparing with the radial compliance of pig's carotid, ranged from 7.21% to 10.04%/100 mmHg, there was a big gap between them. And also the trend of the radial compliance of vascular prostheses was different from the real pig's carotid. There is a lot of work left to improve the radial compliance, not only to change the vascular prostheses' compliance, but also to meet with the real vascular.

Anatomical and Functional Preliminary Results of Total Non-Cemented Hip Prostheses

The aim of this work was to assess the preliminary anatomical and functional results of patients to establish prospects. Materials and method: We report here the preliminary results of a retrospective mono-centric, homogeneous and continuous series, of 21 non-cemented total hip implants, implanted from January 2011 to December 2014. The mean follow-up time was 24 months. The patients were evaluated by Harris’s hip at the last follow-up. Results: The mean age of the intervention was 30 years. In our series, we observed a male predominance (60% of cases). Clinically, the Harris score varied significantly from 52.6 ± 11.4 pre-operatively to 85.1 ± 5.1 during the last follow-up visit. Among the items in the score, pain was the parameter that showed the greatest improvement. Thigh pain was observed in only one patient operated on the two sides. At the level of radiology, the femoral implant showed great stability. Bone resorption was suspected in 14 cases (66.66%), and confirmed in 4 cases (19.04%) with excellent bone remodeling, illustrated by the Engh and Massin scores. A loosening and a prosthetic dislocation was observed in a patient (4.76%). Any heterotopic ossification was observed. Conclusion: Our study confirmed good clinical and radiological results of the non-cemented hip prosthesis series in young patients. The rates of aseptic loosening, acetabular edges or osteolysis are low and stable over time.

Anticoagulation in Pregnant Women with Mechanical Heart Valve Prostheses: 25-Year Experience at a Tertiary Care Hospital in a Developing Country

The aim of this retrospective study was to compare the different anticoagulation regimens used in pregnant women with prosthetic heart valves. We reviewed 86 pregnancies in 57 women from 1987 to 2011. The patients were divided into two groups: group A (39 pregnancies) had oral acenocoumarol throughout pregnancy;and in group B (47 pregnancies), acenocoumarol was replaced by subcutaneous heparin during the first trimester. Both groups received heparin at the time of delivery. The valves replaced were mitral (59.65%), aortic (12.28%), or both (28.07%). 74 pregnancies (86.04%) resulted in live births, 9 (10.46%) had stillbirths, 1 (1.16%) had spontaneous abortion and 2 (2.32%) underwent therapeutic abortions. The live birth rate was higher in women on heparin (87.23%) compared with those on acenocoumarol (84.61%). No malformations appeared in the 74 newborns, except for one case of hydrocephalus. There was one maternal death due to acute mitral valvular thrombosis while on heparin in the first trimester. Hemorrhagic complications occurred in 13 patients in the postpartum period, 4 of whom required transfusion. No anticoagulant regimen can be said to be entirely safe for use during pregnancy as there is a degree of risk with each regimen. Heparin does not offer a clear advantage over oral anticoagulation in the pregnancy outcome.

Iatrogenic Oesophageal Perforations in Neoplastic Lesions: Management with Covered Self-Expanding Prostheses

Background:Perforation of the oesophagus is a serious condition. Most of them are iatrogenic and are associated with significant morbidity and mortality, especially with late diagnosis. Aim: To prospectively analyse the results of the endoscopic management of iatrogenic perforations in oesophageal neoplasia, through the immediate insertion of a covered self-expanding prosthesis (CSES). Materials and Methods: Between 01.01.2006 and 12.30.2016, a series of 19 consecutive patients attended the Teaching Unit of Endoscopic Surgery of the Regional de Concepción Hospital, Chile, with the diagnosis of oesophageal neoplasia confirmed by biopsy were prospectively studied. All were subjected to a prior evaluation by the oncology team and subsequently referred for endoscopic palliative management of dysphagia. The average age was 77 ± 9.3 years, 8 (42.1%) were female and 11 (57.9%) were male. In 17 patients (89.5%) the stenosis compromised the oesophagus, in 2 (10.5%) the gastro-oesophageal junction, 16 had a squamous carcinoma (84.2%) and 3 an adenocarcinoma (15.8%). Results: Perforation was diagnosed during the procedure in 18 patients (94.7%) and in 1 (5.3%) 22 hours later. Follow-up was done for a minimum of 90 days or until death. The prostheses were inserted successfully in all cases. The immediate evolution was satisfactory in 12 patients (63.2%). In the rest (36.8%), 18 complications appeared. The most frequent were retrosternal pain, subcutaneous emphysema and fever. The early evolution was satisfactory in 12/19 cases (63.2%). Complication was evidenced in 7 (36.8%), the most frequent was retrosternal pain (36.8%). Fever occurred in 3 (15.8%), pleural effusion in 3 (15.8%) and mediastinitis in 2 of these. The prosthesis was kept in situ as a definitive palliation method for neoplastic dysphagia. In 10 of the 18 cases that survived more than a month, there were late complications (55.6%), none of them associated with the perforation itself. The only death (5.3%) was due to an oesophagus-pleural fistula, associated with an early prosthetic migration. Recovery of the oral intake occurred, on average, at 3.7 days. The hospital stay averaged 9.6 days. Conclusion: The use of CSES for the treatment of iatrogenic oesophageal perforations in the context of neoplasia, is a safe and effective method, with low morbidity, adequate recovery of the oral intake and prompt discharge from hospital.

Influence of Ni and Cr Content on Corrosion Resistance of Ni-Cr-Mo Alloys for Fixed Dental Prostheses in 0.05% NaF Aqueous Solution

The Ni-Cr-Mo alloys have been used as dental prostheses because they own a good mechanical strength, high corrosion resistance and even to be economically viable. These alloys corrosion protection against in salt solutions typical of physiological media is due to passivation phenomenon with an oxide surface layer formation, mainly chromium oxides. This protective film, subjected to a mechanical stress in a corrosive environment, can partially dissolve by releasing ions, which have deleterious effects in a human body. Fluoride ions, existing in hygiene products, change the buccal environment and their presence may enable a localized corrosion process initiation. The aim of this work has been to investigate the chemical composition influence of three alloys in corrosion resistance to: A (Ni-73% Cr-14% Mo-8.5% Be-1.8% Al-1.8%), B (Ni-61% Cr-25% Mo-10.5% Si-1.5%) and C (Ni-65% Cr-22.5% Mo-9.5%) in media containing fluorides that simulate mouthwashes solution. The study has been done in a 0.05% NaF solution, pH 6, at 37°C using electrochemical techniques. The alloy with the highest nickel and the lowest chromium content is not passive in the middle studied, showing a continuous increase in current density with the potential increasing, while the other alloys show passivation range of 600 mV and passive current density of about 10-6 A/cm2.

Visual prostheses, optogenetics, stem cell and gene therapies: splitting the cake

The size of the blind population in 2015 was estimated to be approximately 36 million（Bourne et al.,2017）.According to the predictions by Bourne and co-workers,the number of the visually impaired is expected to reach nearly 100 million by 2050.

Implant-Supported Full Fixed Prostheses with a Removable Oro-Nasal Obturator for the Edentulous Maxilla with Palatal Fistula due to Surgical Procedures for Oral Cancer

Open oro-nasal defects resulting after oral tumor resection need structural and functional rehabilitation using dental prostheses. Conventional removable prostheses have usually been indicated and performed for prosthodontics. When the patient has an edentulous maxilla, the unfavorable stability of the prosthesis will cause dysfunction of mastication and pronunciation. To achieve improvement of the impaired functional situation, implant-supported full fixed prostheses (IPSPs) for the edentulous maxilla with a removable obturator offer a reasonable solution. We present herein the case of a 70-year-old Japanese man who has presented with oro-nasal defect due to surgical procedures for oral cancer. He was treated with implant-supported full fixed prostheses in a conventional two-step procedure. After prosthesis treatment, a palatal obturator was set. The patient has shown no clinical or radiological evidence of failure as of 24 months after the end of treatment. Functional evaluation of mastication and pronunciation showed dramatic improvements. For a patient with an edentulous maxilla and palatal fistula, full-arch fixed prostheses supported by a combination of axially and non-axially positioned implants and a removable oro-nasal obturator, using the anterior alveolar bone, without bone transplantation or maxillary sinus elevation, could offer an effective, minimally invasive treatment alternative.

Towards Long-Life Replacement Joint Prostheses - A Surface Engineering Approach

How to improve the wear resistance of bearing surfaces, hereby achieving long life of orthopaedic joint prostheses has long been a technical challenge with much fundamental interest and social and economic impacts. Surface engineering has been emerging as one of the most promising technologies to improve the tribological properties of biomedical materials. A current area of research within the Birmingham Surface Engineering Group has been directed at developing novel surface engineering technologies for biomedical materials towards long-life joint prostheses. Following a brief introduction, the author reports their recent progress in the surface engineering of biomedical materials particular for joint prosthesis. The potential of these innovative surface engineering technologies in enhancing the performance of oral and maxillofacial implants and surgical devices is also discussed.

骨水泥与生物型假体半髋关节置换在治疗老年骨质疏松相关股骨颈骨折术后早期步态对比分析

目的运用步态分析技术比较骨水泥与生物型半髋假体在治疗老年骨质疏松相关股骨颈骨折术后早期不同时间段的步态变化,探讨两种假体植入术后早期的康复效果。方法通过分析2021年1月至2022年1月于河北省沧州中西医结合医院髋部创伤科半髋关节置换的患者资料,共60例;后外侧入路骨水泥假体半髋关节置换手术(30例),后外侧入路生物型假体半髋关节置换手术(30例)。采用步态分析技术比较每组患者术后1、3、6个月的行走时步长、步速、步频、行走时髋关节活动度的改善情况及两组患者之间的差异,以及两组患者术后1、3、6个月改良髋关节(MHHS)评分变化。结果两组患者的步长、步速、步频、髋关节外展活动度在术后3、6个月检测结果较术后1个月改善明显(P<0.05)。术后1、3个月时,骨水泥假体组患者的行走时步长、步频、步速、髋关节外展活动度检测结果优于生物型假体组(P<0.05);术后6个月时,两组各指标比较差异无统计学意义(P>0.05)。骨水泥型假体组与生物型假体组术后1、3、6个月的改良Harris评分差异无统计学意义(P>0.05)。但两组的术后3、6个月的MHHS评分均比术后1个月的评分要明显提升(P<0.05)。结论两种假体都可使骨质疏松老年股骨颈骨折获得明显的步态改善,但骨水泥型假体治疗老年骨质疏松相关股骨颈骨折可以早期促进患者髋关节功能的恢复和锻炼。

不同假体在膝关节骨关节炎患者全膝关节置换术中的应用效果对比

目的:对比膝关节骨关节炎(KOA)患者全膝关节置换术中采用不同假体的效果。方法:回顾性选取中国人民解放军联勤保障部队庐山康复疗养中心2020年4月—2023年4月收治的80例接受全膝关节置换术治疗的KOA患者的病历资料进行研究,依据全膝关节置换术中采用的假体类型将其分为A组(固定平台假体)和B组(高屈曲旋转平台假体),各40例。对比两组围手术期相关指标(手术时间、术中出血量、引流管拔除时间、住院时间)、膝关节功能[Lysholm膝关节评分、西大略和麦克马斯特大学(WOMAC)骨关节炎指数评分]、炎症因子[白细胞介素-6(IL-6)、C反应蛋白(CRP)]及术后并发症发生情况。结果:两组围手术期相关指标对比,差异均无统计学意义(P>0.05)。术后3个月,两组Lysholm膝关节评分均显著上升,且B组高于A组,两组WOMAC骨关节炎指数评分均显著下降,且B组低于A组,差异均有统计学意义(P<0.05)。出院前1 d,两组IL-6、CRP均显著下降,且B组均低于A组,差异均有统计学意义(P<0.05)。两组术后并发症发生率对比,差异无统计学意义(P>0.05)。结论:高屈曲旋转平台假体与固定平台假体均可达到良好手术效果,但相较于固定平台假体,高屈曲旋转平台假体能更显著提高KOA患者全膝关节置换术后膝关节功能,且可改善术后炎症状况。

纺织基人工血管管壁结构对其性能的影响规律

为提高人工血管临床使用的安全性和有效性,研究纺织基人工血管壁结构对人工血管性能的影响规律。以涤纶复丝为原料,纬纱股数和经密为变量,制备4种不同规格的人工血管管坯试样。试样总紧度分别为79.6%、82.0%、89.2%和96.4%。分析4种不同管壁结构对人工血管水渗透性以及生物力学性能的影响。研究结果表明:管壁的水渗透性和生物力学性能与管壁织物总紧度呈指数关系;当试样经密为900根/10 cm,纬纱为双股(222 dtex/96 f),总紧度为96.4%时,性能最优。此时,孔隙率为50.95%,水渗透量仅为12.1 mL/(cm^(2)·min),周向拉伸强度达243.5×10^(-5)kN/mm,探头破裂强度达595.23×10^(-3)kN,性能最优,且优于国产商用机织涤纶人工血管,有一定的参考意义。

Testicular prostheses-impact on quality of life and sexual function

Orchiectomy is the recommended treatment for many testicular conditions.However,testicular prosthesis placement is not always performed for different reasons.In this study,we aimed to evaluate patients'opinions and the impact on sexual function and quality of life.This retrospective observational single-center study included patients who underwent orchiectomy between January 2014 and December 2020 at the Department of Urology,Braga's Hospital(Braga,Portugal),where testicular implants were always available and the decision to undergo the procedure was made fully independent of cost.Patients completed four questionnaires that assessed demographic data,satisfaction,self-esteem,and sexual function.Of the 96 patients who underwent orchidectomy,59 replied to the questionnaires,and of these patients,86.4%decided to undergo silicone-based testicular prostheses implantation.The remaining 13.6%refused the implant based on concerns about complications(37.5%),because they felt that it was unnecessary(37.5%),or because it was not offered by the doctor(25.0%).Overall,96.1%of these patients were satisfied with the implant;however,25.5%classified it as"too firm".No statistically significant differences were found in sexual function(all P>0.05).However,it can be observed that there are more patients with prostheses presenting normal sexual activity compared to patients without prostheses(74.0%vs 50.0%),and none of them reported severe erectile dysfunction(0 vs 16.7%).Regarding self-esteem,both patients with and without prostheses present very similar average scores with no statistically significant differences.The present study highlights the highest level of satisfaction among patients who received testicular prostheses.Testicular prostheses implantation is a safe procedure that does not hamper sexual function after orchiectomy.

二硅酸锂基玻璃陶瓷单端树脂粘接桥修复个别前牙缺失的临床应用

目的探讨二硅酸锂基玻璃陶瓷单端树脂粘接桥修复个别前牙缺失的临床效果,为个别前牙缺失修复方式的选择提供参考。方法本研究已通过单位伦理委员会审查批准,并获得患者知情同意。选取42例单颌前牙缺失数量在两颗内的患者,采用二硅酸锂基玻璃陶瓷单端树脂粘接桥修复,修复后6个月、1年、2年、3年进行随访,评价美学、功能修复效果及牙周健康状况,并采用视觉模拟评分量表(VAS)调查患者的满意度。结果观察期间,42例二硅酸锂基玻璃陶瓷单端树脂粘接桥修复的患者中有1例3个月内连接体发生断裂,1例2年内发生脱粘;美学修复效果的等级均评定为A级;修复后牙周健康状况良好,基牙及桥体下的软硬组织无临床吸收现象,评价指标均为A级;患者总满意率为100%。结论对于个别前牙缺失,二硅酸锂基玻璃陶瓷单端树脂粘接桥可达到微创、固位牢靠、美观舒适和生物相容性好的修复效果,患者满意度高,在临床中可以考虑作为一种理想的修复方式。

种植固定修复义齿邻接丧失的研究进展

邻接丧失是口腔种植修复后的常见并发症之一,其发病率较高,且具有独特的解剖和生理特征。邻接丧失容易引起食物嵌塞,引发种植体周围组织创伤及邻近牙齿的龋病或牙周组织炎症,且治疗方式有限,影响种植修复的预后和患者满意度,因此对种植义齿邻接丧失进行研究至关重要。