应用CAD/CAM与快速成形技术重建颌面器官

目前,国内医院对治疗半侧颌面萎缩类疾病中的耳、眼缺失仍然采用技师手工翻制蜡模的方法。本文从医工结合的角度,采用患者CT数据或激光扫描数据,将CAD/CAM技术与快速成形技术(Rapid prototyping,RP)结合用于患者半侧耳及眼缺失治疗,可通过RP模型直接生成硅橡胶赝复体。临床结果表明该方法成功地提高了赝复体的外形精度,并可使之与病人的缺损面周围组织完美衔接,对医工结合领域的发展具有重要的意义。     

数字化赝复体在兔腭瘘修复中的应用

文题释义： 腭瘘：又称腭穿孔和腭瘘孔,腭瘘的临床表现为从牙槽突至悬雍垂某一结构区域遗留口鼻腔贯通的组织缺损,为腭裂术后最常见的并发症。 数字化印模技术：是指将光学、电子技术及计算机图像识别和处理技术结合在一起,通过口内光学扫描,将获取的光学信号转换为计算机所能识别的电子信号,将实体物体转换为虚拟数字信息,从而获得三维数字模型。 背景：数字化印模技术在口腔领域应用广泛,与传统印模技术相比,其更加便利化、精准化。 目的：探讨数字化赝复体在兔腭瘘修复中的应用效果。 方法：用手术方法建立兔腭瘘动物模型,术后1个月利用数字化口内扫描系统对10只兔腭瘘动物模型行口内腭瘘缺损区域数字化扫描,通过数字化印模技术,基于数字化设计,制作兔腭瘘医用硅橡胶赝复体,试戴赝复体后,检查其精确性能、固位性能及封闭性能。实验方案经西南医科大学附属口腔医院动物实验伦理委员会批准。 结果与结论：数字化赝复体修复腭瘘后,赝复体的精确性能、固位性能及封闭性能良好。提示通过数字化印模技术,数字化赝复体实现了对兔腭瘘的精确修复,有一定的临床应用价值。 ORCID: 0000-0001-8250-9393(孙黎波) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

硅橡胶赝复体色彩稳定性的影响因素

背景:目前,硅橡胶作为颌面部缺损常用的修复材料在临床修复中得到广泛应用,然而,赝复体硅橡胶的色彩不稳定性是造成其使用寿命缩短的主要因素。目的:对影响赝复体硅橡胶色彩稳定性的因素进行总结,为临床应用提供参考依据。方法:分别以"硅橡胶;赝复体","siliastic;prosthesis"为检索词,应用计算机检索重庆维普(VIP)期刊全文数据库及Pubmed数据库1987-09/2009-12有关文章。纳入有关硅橡胶变色的文献。排除与研究目的无关和内容重复者。保留38篇文献做进一步分析。结果与结论:总结了赝复体硅橡胶变色的多种影响因素,其中,光学性质、着色、以及材料的老化与赝复体硅橡胶色彩的稳定性密切相关。针对上述因素,研究利用其相关预防措施延缓赝复体的变色,增加赝复体的使用寿命是当前面临的重要课题。对于从分子水平探索赝复体色彩不稳定性的机制,尚需进一步研究。     

可摘局部义齿上颌赝复体设计及其生物力学评价

对单侧上颌缺损的腭部封闭式和阻塞式赝复体进行几何仿真,并对这两种重建方法分别进行卡环和附着体固位方式设计,并对重建的生物力学效果进行了对比研究。模拟加载肌肉约束和力边界条件,分析四种不同上颌赝复体的应力分布,综合考虑义齿、基托、牙面板、阻塞器、卡环和附着体结构等强度问题,以及余留牙和赝复体的应力大小和分布趋势。根据应力结果,优化设计,为赝复体的临床成功作出生物力学的评价。分析结果表明:整个赝复体修复上颌结构各部分应力都在强度允许范围内,余留天然牙和牙槽骨上应力分布合理,赝复体有效传导力。阻塞器式赝复体材料属性与牙槽骨比较接近或略低于骨,填充了缺损侧上颌空腔,增大了与上颌的接触面积,使应力有效传导,在结构上较上腭封闭赝复体更为合理。四种赝复体天然牙应力和位移值比较表明,附着体固位阻塞器赝复体避免了天然牙应力集中,对义齿赝复体的固位和动力支持都非常有利。     

三种颌面赝复硅橡胶耐臭氧老化性能的对比

背景:颜面部硅橡胶赝复体长期暴露于空气中,受到光、热、臭氧等外部因素的影响,会发生物理或化学变化,导致硅橡胶变色、发黏、变硬、变脆,物理机械性能逐步下降,表现为强度降低、弹性消失,最终导致失去使用价值。目的:对比ZY-1、SY-1及A-2186三种赝复硅橡胶臭氧老化前后的机械性能,评价ZY-1硅橡胶的耐臭氧老化性能。方法:按照GB/T7762-1987《硫化橡胶耐臭氧老化试验静态拉伸试验法》中的规定,分别对3种硅橡胶材料老化前后的机械性能进行测定,并对结果进行统计学分析。结果与结论:经过臭氧老化后,ZY-1、A-2186及SY-1赝复硅橡胶拉伸强度、扯断伸长率以及撕裂强度均下降,而硬度和永久变形率升高;ZY-1赝复硅橡胶扯断伸长率、撕裂强度的老化百分变化率以及邵氏硬度明显小于SY-1赝复硅橡胶(P0.05),与A-2186赝复硅橡胶接近(P0.05)。说明ZY-1赝复硅橡胶在臭氧老化作用下,可保持良好的弹性和硬度,具有良好的耐臭氧老化能力。     

氧等离子处理人工晶状体材料的生物相容性

背景：氧等离子处理可有效改善双组分室温硫化硅橡胶人工晶状体材料表面的亲水性能和生物相容性,但等离子体聚合形成的薄膜可能产生卷曲和破裂或因与基质是非共价键结合而产生剥离,影响材料本身的理化性能和光学性能。 目的：初步评价优选氧等离子处理表面改性后双组分室温硫化硅橡胶人工晶状体材料的体外生物相容性。 方法：采用氧等离子体表面改性技术修饰疏水性双组分室温硫化硅橡胶人工晶状体材料的表面,处理功率及时间分别为：20 W、50 W、100 W和30 s、1 min、3 min、10 min。应用视频光学接触角测定仪、傅里叶变换衰减全反射红外光谱和X射线光电子能谱分析材料表面亲水性和表面化学元素组成;扫描电子显微镜和原子力显微镜观察材料表面形貌。通过人晶状体上皮细胞黏附实验观察双组分室温硫化硅橡胶表面改性前后细胞的数量及形态改变。 结果与结论：最佳改性条件为100 W,30 s,20 mL/min,40 Pa。此条件改善了双组分室温硫化硅橡胶人工晶状体材料表面的亲水性,对材料表面无刻蚀作用,改善了人晶体上皮细胞在双组分室温硫化硅橡胶人工晶状体材料表面的生物相容性。     

仿真材料的赝复法修复耳郭部分缺损

背景：耳郭畸形的治疗方法包括义耳赝复、肋软骨植入、Madpor支架植入及骨合种植等,但利弊各异,效果上各有优劣。 目的：采用仿真材料的赝复法治疗部分耳郭缺损患者,并评估其赝复效果。 方法：选用部分耳郭缺损的小耳畸形患者2例,根据耳郭缺损的情况,以双组份室温固化硅橡胶制作出赝复体,借助医用黏合剂固定赝复体至缺损部位。分别在不同光线、距离和环境下评估赝复效果以及患者自身满意度。 结果与结论：纳入的2例部分耳郭缺损患者经赝复法治疗后其耳郭可达到良好视觉效果。赝复法治疗部分缺损的小耳畸形患者,方法简单无需手术,可重复性好,易于维护。自然光线下,室外赝复物肉眼分辨距离低于1.5 m时,患者表现出较高满意度。     

半侧上颌骨缺损赝复体修复固位方案的生物力学评价

目的 对3种单侧上颌骨缺损赝复体修复方式——卡环固位、一根/两根颧种植与卡环联合固位进行生物力学评价。方法 基于CT扫描数据建立正常人颅骨的三维有限元模型,通过三维有限元法计算分析3种重建模型中上颌复合体的应力分布,综合比较赝复体、基牙、卡环、种植体、颧骨的应力水平。结果 单一的卡环固位,基牙应力峰值达130.7 MPa,赝复体产生位移4.439 mm,卡环应力峰值达452.4 MPa,健侧眶缘应力为23.32 MPa;加入一根颧种植后,卡环应力减小至118.1 MPa,基牙应力峰值为31.12 MPa,健侧眶缘应力仅为5.387 MPa。两根颧种植体固位方式下,颧骨应力由66.11 MPa减小到48.12 MPa;颧种植体上的最大应力也由500.2 MPa降至313.8 MPa。 结论 颧种植与卡环联合固位,颌面骨骼应力分布更符合咬合力传导规律。研究结果将为人体上颌单侧缺损重建方案设计和优化提供重要参考数据。     

新型赝复体用硅橡胶材料的体外细胞毒性评价

本文对自制赝复体用硅橡胶材料的体外细胞毒性进行测定与评价,为后期临床应用提供依据。参照国标GB/T16886.5-2003,采用CCK-8法检测新型硅橡胶对小鼠成纤维细胞L929的细胞毒性,计算细胞相对增殖率,通过倒置相差显微镜和扫描电镜观察细胞形态。结果表明新型硅橡胶材料的细胞相对增殖率为91.65%(24h)、87.03%(48h)和87.30%(72h),细胞毒性1级,存在轻微细胞毒性。电镜观察24、48和72h的细胞均呈现典型的长梭形、长三角形形态,细胞生长良好。结果显示,新型硅橡胶材料在细胞毒性方面,符合生物医学材料要求。     

同种异体软骨听骨赝复物与羟基磷灰石听骨赝复物修复听骨链损伤的比较

背景:以往多采用同种异体软骨听骨赝复物作为听骨链重建的材料,近年来羟基磷灰石听骨赝复物已广泛地应用于鼓室成形术的临床工作中。而目前有关两种听骨赝复物在鼓室成形术、听骨链重建中的临床疗效比较尚无相关报道。目的:比较两种听骨赝复物的临床疗效,旨在探求更适宜临床推广应用的听骨赝复物。方法:将进行鼓室成形、听骨链重建术的慢性中耳炎患者60例分为同种异体软骨听骨赝复物组和羟基磷灰石听骨赝复物组,两组在术前、术后进行纯音听力测试,以语言频率区(0.5,1.0,2.0kHz)听阈气导平均值及气骨导差平均值统计,取最后一次(至少6个月以后)复查听力结果作为组间对比指标之一。同时记录两组病例移植鼓膜愈合情况,即移植鼓膜良好上皮化的时间,两组听骨赝复物的脱出率。结果与结论:在相同病变类型、相同术式患者中,同种异体软骨听骨赝复物与羟基磷灰石听骨赝复物植入后听力恢复水平方面差异不显著(P0.05),术后移植鼓膜愈合情况方面差异不显著(P0.05)。在相同病变类型、相同术式的术后赝复物脱出率均为0。提示同种异体软骨听骨赝复物与羟基磷灰石听骨赝复物在慢性中耳炎患者行鼓室成形、听骨链重建术中的临床疗效相似。     

纳米铁显影增强硅橡胶的制备及影像可视性评价

目的 探讨纳米铁微粒作为显影标记物对医用硅橡胶改性的可行性并评价复合材料的影像可视性.方法 硅油与纯铁粉、碳包铁粉混合,按预定的配方比分别与甲基乙烯基硅橡胶共混、密炼、模压、硫化,得到纳米纯铁粉增强硅橡胶（第1组）、纳米碳包铁粉增强硅橡胶（第2组）,空白对照组为医用硅橡胶.CT扫描体外各组材料试件,获取图像并测得CT值,比较组间CT值均值的差异性;将2组材料试件植入犬皮下,获得标准X-线图像;X射线衍射技术分析材料内铁微粒的组分稳定性.结果 分别制备出铁粉显影增强硅橡胶和碳包铁粉显影增强硅橡胶,新材料在体内外的X-线图像清晰可见,复合材料的CT值随金属纳米粉体量和纳米微粒原子量的增加而增加,2组材料的CT值均值、组间配方比相同的材料的CT值均值差异显著（P＜0.001）;材料放置180 d后,单质铁出现衍射峰的位置基本没有变化,分散在硅橡胶中的纳米纯铁微粒、碳包铁微粒较为稳定.结论 金属纳米铁粉、碳包铁粉可作为硅橡胶显影性改良的标记物.     

医用硫化橡胶中游离硫含量的测定——亚硫酸钠法质疑

本文对用亚硫酸钠法测定医用硫化橡胶中的游离硫是否科学,提出了疑问,并阐述了作者自己的观点。     

Solid-state 13C NMR studies of vulcanized elastomers, 4. Sulfur-vulcanized polybutadiene

The sulfur vulcanization of cis-1,4-polybutadiene was studied by solid-state ¹³C NMR spectroscopy. Polybutadiene is cured with several different formulations including sulfur and accelerators in order to determine the network structure of the resulting vulcanizates. Polysulfidic crosslinks bound to the methylene carbons of the polybutadiene repeating unit were observed in the rubber network. Cyclic sulfide structures were detected in the network structure in addition to cis-to-trans chain isomerization. Two different pulse sequences were used for the NMR experiments of the sulfur-vulcanized cis-polybutadiene. The gated high power decoupling NMR experiment reflects the mobile regions of the vulcanizate sample while the cross polarization pulse sequence reflects the regions of the sample which are inherently more rigid. The cross polarization spectra of the samples cured with high sulfur levels showed that a considerable amount of rigidity is found in the vulcanized cis-polybutadiene network. It was also possible to obtain cross polarization spectra of the lightly crosslinked polybutadiene vulcanizates. This is in contrast to the NMR results of the vulcanized natural rubber systems which generally tended to have considerably more mobility.     

Toxicity testing of medical device materials tested in human tissue cultures

Rubber and plastic parts of medical devices were applied to human cell monolayers either directly or as aqueous extracts made at different time/temperature conditions. Thirteen rubber and twelve plastic samples were tested. The cultures were observed and photographed by use of a microscope with a camera before and after treatment with the test materials. The toxicity of the specimens was evaluated by comparison of the photographs. Alterations or disappearance of the cells or inhibited growth were interpreted as toxic effects of the materials. Twelve of the rubber and six of the plastic samples were evaluated as toxic in one or more of the systems.     

Solubility and diffusion coefficients of gaseous formaldehyde in polymers

The solubility and diffusion (desorption) coefficients of gaseous formaldehyde in 14 materials have been measured at different temperatures. Cellulose, paper, polyamide (Nylon 6), polyester and natural rubber (latex) show very high values of formaldehyde solubility and very low diffusion coefficients, with a weak or inversed influence of the temperature, leading to the conclusion that a chemical reaction occurs with the formaldehyde. The behaviour of the other polymers follows the classical laws of solubility and diffusion of gases except for silicone rubber which shows two-phase desorption curves.     

Schlagzähe styrolpolymerisate

The structure of impact styrene polymers and its relation to mechanical behaviour is discussed in detail. These materials consist of a brittle component, e.g. polystyrene, and a rubbery component dispersed in the brittle phase. As these systems form several phases, the mechanical coupling between the rubber particles and the brittle phase, their size distribution, and the thermal behaviour of the rubber exert an essential influence on the mechanical properties of the product. The glass transition temperature of the rubber is especially important in this respect. Variation of the process and selection of suitable rubbers are shown to determine the mechanical properties to a great extent. These properties can be predicted within certain limits by some physico-chemical methods which proof to be very useful for development and improvement of products.     

Propriétés physiques et mécaniques d'un copolymère séquencé polystyrène-polyisoprène-polystyrène hydrogéné

Differential scanning calorimetry (DSC) and stress-strain measurements have been made on a polyisoprene hydrogenated polystyrene-polyisoprene-polystyrene (SIS) elastomeric block copolymer and compared with those of the corresponding nonhydrogenated copolymer. The SIS copolymer was prepared by anionic polymerization with butyllithium in benzene. Both polymers are two-phase amorphous elastomeric materials displaying two glass transition temperatures. The transition temperature of the hydrogenated polyisoprene phase is only 4°C higher than that of the polyisoprene phase in the unhydrogenated material. Stress-strain curves measured on solvent cast films before and after hydrogenation show identical behaviors at low elongation. Both the tensile strength and elongation at break are smaller for the hydrogenated polymer. Comparison between the stress-strain curves measured in successive extension cycles shows that this polymer does not exhibit the “leathery” behavior generally observed for SIS elastomeric block copolymers, but behaves more like a typical vulcanized elastomer. This would indicate more rigid and much better separated polystyrene particles in the hydrogenated system.     

Reactive Compatibilization of NBR/EPDM Blends by the Combination of Mercapto and Oxazoline Groups

Summary: The reactive compatibilization of ethylene‐propylene‐diene (EPDM)/nitrile rubber (NBR) blends was performed using mercapto‐modified copolymers (mercapto‐modified EPDM, EPDMSH, and mercapto‐modified ethylene‐vinyl acetate copolymer, EVASH) in combination with oxazoline‐functionalized NBR (NBR‐ox). The best mechanical performance was achieved with the two EVASH‐based compatibilizing systems, especially the one containing the co‐reactive copolymers because of the reactivity of the oxazoline group. The presence of insoluble material in non‐vulcanized blends suggested the reactive compatibilization. The morphologies of these blends were examined through scanning electron microscopy (SEM). Blends compatibilized with the EVASH‐based systems showed finer morphologies than the non‐compatibilized blend or those compatibilized with the EPDMSH‐based systems. In non‐vulcanized NBR/EPDM (70:30 wt.‐%) blends, the presence of the co‐reactive EVASH/NBR‐ox system changes the morphology from a cocontinuous structure towards a droplet‐matrix morphology, and also results in a significant broadening of the damping curve related to the NBR transition, observed from DMTA analysis. The effect of the compatibilization on aging resistance has also been evaluated.

SEM micrograph of a non‐vulcanized NBR/EPDM blend compatibilized with a NBR‐ox/EVASH co‐reactive copolymer.     

四种常用假肢材料与人体皮肤摩擦学特性的研究

研究了目前应用广泛的四种假肢接受腔及内衬套材料与皮肤的摩擦学特性，试验部位分别选择在小腿截肢残疾患者的残肢及正常人小腿胫骨脊外侧进行。试验前对皮肤和材料的表面形貌、材料亲水性进行了测试。摩擦学试验结果表明，法向载荷P为0．3N和0．7N下，由于硅橡胶具有特殊性质（含有硅油），与皮肤摩擦系数明显大于其他材料，并且在残疾人和正常人皮肤之间具有明显差异（P〈0．05）；其它三种材料均符合“材料表面越憎水、与皮肤的摩擦系数越低”的规律。法向载荷P为8N下，残疾人和正常人皮肤与各材料之间的摩擦系数无明显差异（P〉0．05）。