预加热对两种复合树脂机械性能的影响

目的：探讨预加热对两种光固化复合树脂机械性能的影响。方法：采用混合填料树脂Z250和纳米树脂Z350分别制作40个树脂试件并分为两组,分别进行常温23℃和加热40℃处理,使用发光二极管（LED）光固化灯固化40 s,测定表面显微硬度和抗压强度,并进行对比分析研究。结果：两种材料加热40℃处理后其表面显微硬度和抗压强度均高于常温23℃处理组,有统计学意义（t＝-5.189,P＜0.01）。结论：预加热可以提高光固化复合树脂机械性能,推荐临床使用。     

四海文摘

牙齿美容普及有望爱美之心,人皆有之。因牙齿变色、牙体缺损、牙裂不齐而影响美观者,使用可见光固化复合树脂修复一般能达到美容的目的。但由于价格较贵,必须使用光固化机照射才能固化,因此,尚难普及。北京古莎生物材料有限公司引进德国贺利氏古莎公司生产线生产的依斯蒂克(Estic)自凝复合树脂解决了这一难题。该材料采用与可见光固化复合树脂相同的超微玻璃作为填料,克服了过去自凝树脂强度差、易     

固化光源对复合树脂修复牙体缺损效果的影响

光固化复合树脂因具有色泽美观、物理机械性能良好、操作简便等优点,在口腔临床中的应用越来越广泛.光固化复合树脂材料在临床应用中逐渐发现了一些问题,其中最突出的一点就是固化效果的差异,这除了与操作手段等因素有关外,固化光源即光固化机是其中一个关键因素.光固化复合树脂的聚合需要光敏引发体系的引发,而此种聚合在很大程度上受固化光源的影响,因此固化光源的种类及其应用对于光固化复合树脂的应用有重要的意义.近年来复合树脂固化光源的种类越来越多,光固化复合树脂经由不同固化光源固化后的性能有所不同,并且不同固化光源采用不同的固化方式固化后的性能也有差异,各种研究层出不穷,结论也各有差异.本文对近年来对于固化光源及相关内容做一综述,以为临床选择有效的固化光源提供参考.     

P60纳米复合树脂充填修复后牙髓反应的临床研究

目的：研究分析活髓后牙龋洞用3MTMESPEFiltekP60后牙专用纳米复合树脂充填修复后牙髓反应原因。方法：据后牙龋一类窝洞的深度,将109颗患牙分为深层窝洞组（位于釉牙本质界下1.5~2mm）31颗,中层窝洞组（位于釉牙本质界下1~1.5mm）46颗,浅层窝洞组（位于釉牙本质界下0.5~1mm）32颗。其中,深层窝洞用Dycal护髓,GIC垫底后用3MP60纳米复合树脂充填修复,中层窝洞和浅层窝洞直接用P60复合树脂充填。充填修复后2周、1个月和12个月进行复查。结果：深层窝洞组激发痛的发生率为45.16%,中层窝洞组为27.78%,浅层窝洞组为6.25%。经字2检验,差异具有统计学意义（P〈0.01）。结论：3MP60复合树脂应用于活随后牙深层窝洞的充填修复时,复合树脂中的未聚合单体、自酸蚀粘接系统、固化灯照射时间过长,强度过大、产生的热量和边缘微渗漏形成的细菌侵入等因素,对牙髓均会引起不同程度的影响。     

改性钛酸钾晶须对硅橡胶软衬材料性能的影响

目的:研究经表面改性的钛酸钾晶须对硅橡胶软衬材料性能的影响。方法:将经硅烷偶联剂KH-570改性过的钛酸钾晶须按照1%、2%、3%、4%、5%的比例添加到硅橡胶软衬材料中作为实验组,未添加者作为对照组,对复合材料的邵氏硬度、拉伸强度进行测试,并计算拉伸伸长率。结果:随着钛酸钾晶须添加比例的增加,邵氏硬度也不断增长,拉伸强度及拉伸伸长率呈先上升后下降的趋势。当晶须的添加量为4%时综合性能最好,其邵氏硬度、拉伸强度、拉伸伸长率分别是(30.92±0.02)、(2.20±0.02)MPa和(365.93±4.28)%,P0.05。结论:当钛酸钾晶须添加比为4%时,软衬材料综合性能达到最佳状态。     

牙体修复材料的发展

牙齿是人体中最硬的器官,牙釉质和牙本质的硬度和压缩强度都很高,因此耐磨性很好,有良好的咀嚼功能,但也很容易遭到破坏。口腔疾病尤其是龋齿为常见的多发病,严重影响人们的健康。龋齿治疗与预防所需要的牙科修复材料经历了几十年的发展取得了长足的进步。各种牙科修复材料也随之不断的发展进步,从传统的银汞合金、玻璃离子再到复合树脂及CAD/CAM嵌体修复。本文以时间顺序分别介绍银汞合金、玻璃离子水门汀、复合树脂等牙体材料的经典性质,并从中总结出牙体修复材料的最新研究进展和发展趋势。     

江门市新会区水源水总硬度的影响因素

目的了解江门市新会区不同类型水源水中总硬度含量的影响因素。方法分析2008-2012年新会区4种类型水源水（河水、水库水、山溪水和井水）总硬度、pH值、氯化物、硫酸盐和硝酸盐的检测值。结果西江、石涧水库、潭江、井水和山溪水的总硬度两两间比较，差异有统计学意义（P〈0．05）。相关性分析结果显示，除石涧水库外，西江、潭江、井水、其他水库和山溪水的总硬度与硫酸盐及氯化物均呈正相关（P〈0．05）；丰、枯水期结果显示，西江总硬度、硫酸盐、氯化物丰水期和枯水期的含量差异有统计学意义（P〈0．05）；潭江总硬度、pH值、硫酸盐、氯化物和硝酸盐丰水期和枯水期的含量差异均有统计学意义（P〈0．05）。结论新会区西江总硬度最高，山溪水总硬度最低。西江、潭江总硬度的主要来源不是大气降水，而是外来污染。     

血管支架径向支撑能力的数值模拟和实验研究

血管支架径向支撑能力的评估方法主要有平面压缩法和径向压缩法两种。本文利用数值模拟进行比较分析发现，这两种方法对支架径向支撑能力测评具有一致性。还介绍了平面压缩法采用数值模拟和实验手段．研究了支架几何参数对支架径向支撑能力的影响．结果表明．在压缩初期径向支撑能力主要受金属覆盖率影响，到一定压缩量后．支撑能力会随膨胀直径的增加、壁厚和金属覆盖率的减小而显著减小。该结果对支架的设计和测评具有指导作用。     

Fuji Ⅱ加强型玻璃离子水门汀修复楔状缺损的临床观察

目的:对比FujiⅡ加强型玻璃离子水门汀与光固化复合树脂修复前磨牙楔状缺损的临床疗效。方法:选择前磨牙楔状缺损的患者120例250颗患牙,随机分为两组。实验组用FujiⅡ加强型玻璃离子水门汀进行修复,对照组用光固化复合树脂进行修复。6～24个月后复查,对比两组病例进行分析比较。结果:用FujiⅡ加强型玻璃离子水门汀修复楔状缺损和光固化复合树脂修复楔状缺损的成功率分别为92.73%和90.43%。统计学无显著差异(P>0.05)。结论:FujiⅡ加强型玻璃离子水门汀与光固化复合树脂修复楔状缺损效果均较满意。     

Bis—GMA／Nano（SiO2-ZrO2）复合树脂牙科材料的制备

目的：对纳米复合树脂牙科材料的制备方法进行研究，从工艺上解决纳米复合材料不够致密问题，使之能较多地应用于临床牙科材料中。方法：用双酚A-甲基丙烯酸缩水甘油酯（Bis—GMA）和双甲基丙烯酸二缩三乙二醇酯（TEGDMA）共同作为树脂基质，利用经过表面处理的纳米无机填料中的一种或者几种填料混合添加制备复合材料，同时采用原位分散法用高速搅拌和超声分散等制备工艺来改善纳米填料分散体系，运用DTA、XRD、SEM等实验手段对Bis—GMA／Nano（SiO2-ZrO2）纳米复合树脂材料进行性能测试及结构表征。结果：利用经过硅烷偶联剂表面处理的纳米SiO2和ZrO2可均匀分散在Bis—GMA基体中．所获得纳米颗粒增强体质量分数高达30％复合材料．制备出了一种力学性能好（致密性高、耐磨性强和硬度大）的数控加工用纳米复合树脂牙科材料。结论：该方法制备出的高性能Bis—GMA／nano（SiO2-ZrO2）复合树脂牙科材料，既美观又坚韧，能充分满足临床牙科修复学需要。     

牙科光固化氢氧化钙盖髓材料的研制

报告树脂基体对牙科光固化氢氧化钙盖髓材料凝固后Ca2释放量、抗压强度及材料浸泡液pH值的影响.试验结果表明,所选树脂基体对材料凝固后Ca2释放量、抗压强度及材料浸泡液pH值有明显的影响.以BEMA或EMA和HEMA为树脂基体材料,凝固后具较好的整体性能,在狗牙上盖髓70天后,可见牙髓组织内形成完整的牙本质桥,显示出良好的盖髓效果.     

Immediate and delayed allergy from epoxy resins based on diglycidyl ether of bisphenol A.

This case report presents two patients with immediate and delayed allergy to epoxy resins based on diglycidyl ether of bisphenol A (DGEBA). In patch testing, the epoxy resin (DGEBA-based) of the standard series gave allergic reactions. Both patients had a prick test reaction of histamine size or larger to the human serum albumin (HSA) conjugate of DGEBA-based epoxy resins. One had been occupationally exposed to methyl tetrahydrophthalic anhydride (MTHPA) and had a histamine-size prick test reaction to the HSA conjugate of MTHPA; the other did not react to the conjugate. Determinations of specific immunoglobulin E were carried out with HSA-DGEBA conjugates, two DGEBA-based epoxy resins, and phthalic anhydrides. The first patient had positive tests to DGEBA, the DGEBA-based epoxy resins, and two phthalic anhydrides, and the second to DGEBA and the DGEBA-based epoxy resins, but not to the phthalic anhydrides.     

五种环氧树脂固化剂的刺激/腐蚀性试验结果及安全防护

目的 定性和半定量评价环氧树脂固化剂对哺乳动物皮肤局部的刺激或腐蚀作用,为皮肤防护提供依据.方法 按照GB/T 21604-2008《化学品 急性皮肤刺激性/腐蚀性试验方法》,对5种常见环氧树脂固化剂进行检测.结果 5种环氧树脂固化剂中,异氰酸酯和酸酐环氧树脂固化剂两种产品皮肤刺激强度为轻刺激性,皮肤刺激反应积分均值分...     

Allergic airway disease caused by methyl tetrahydrophthalic anhydride in epoxy resin

Work-associated rhinitis and asthma occurred in a subject exposed to methyl tetrahydrophthalic anhydride (MTHPA) used as a curing agent in an epoxy resin system. He displayed bronchial hyperreactivity in provocation with methacholine, as well as skin prick test positivity and specific immunoglobulin E (IgE) serum antibodies, against a conjugate of MTHPA and human serum albumin. Thus, it seems likely that the disease was caused by an IgE-mediated allergy.     

光固化义齿软衬材料的研制

本文以甲基丙烯酸聚氨酯为基质，填加稀释剂和光敏引发剂，研制出一种光固化义齿软衬材料。本文研究了甲基丙烯酸聚氨酯中的柔性链段的种类及分子量对软衬材料的力学性能的影响，结果表明，以聚酯合成的材料扯断强度最高，压缩永久变形率最低；以聚丁二醇合成的材料最硬，吸水率和溶出率也最大；以聚丁二烯合成的材料的吸水率及溶出率最小。     

Evaluation of the Mechanical Properties and Drug Permeability of Chitosan/Eudragit RL Composite Film

Objectives

The aim of this study was to design and evaluate a chitosan-based film that has properties required for successful wound dressing, and can control drug penetration and maintenance time in the location.

Methods

Several formulations of a film containing chitosan (3%) and different concentrations of Eudragit RL (0.5%, 1%, and 1.5%) were prepared using the casting/solvent evaporating technique. Mechanical properties, water vapor transmission rate (WVTR), oxygen permeability, water uptake, and nitrofurazone permeability through the films were investigated.

Results

The study results showed that by increasing the Eudragit RL content of composite films, their thickness and tensile strength were enhanced, while their elongation was decreased. No significant difference was observed between the oxygen permeability, WVTR, and water uptake results of pure chitosan films and different composite films containing Eudragit RL. Nitrofurazone permeability of chitosan films was increased by the inclusion of Eudragit RL in composite films, while by increasing the concentration of Eudragit RL, the permeation rate of drug was decreased.

Conclusion

In conclusion, addition of Eudragit RL can improve mechanical properties of chitosan films without any undesirable effect on their water uptake, oxygen permeability, and WVTR qualities. The permeation rate of drugs through the composite films can be modified by changing Eudragit RL/chitosan ratio.     

Occupational contact urticaria caused by airborne methylhexahydrophthalic anhydride.

Acid anhydrides are low-molecular weight chemicals known to cause respiratory irritancy and allergy. Skin allergy has on rare occasions been reported. A total of 3 subjects with occupational exposure to methylhexahydrophthalic anhydride (MHHPA) and hexahydrophthalic anhydride (HHPA) from an epoxy resin system were studied to evaluate the nature of their reported skin and nose complaints (work-related anamnesis, specific IgE, contact urticaria examinations, and ambient monitoring). Using a Pharmacia CAP system with a HHPA human serum albumin conjugate, specific IgE antibody was detected in serum from 1 (33.3%) out of the 3 workers. One unsensitized worker displayed nasal pain and rhinorrhea only when loading liquid epoxy resins into the pouring-machine (2.2 mg MHHPA/m3 and 1.2 mg HHPA/m3), probably being an irritant reaction. Two workers had work-related symptoms at relatively low levels of exposure (geometric mean 32-103 microg MHHPA/m3 and 18-59 microg HHPA/m3); one complained of only rhinitis, and the other was sensitized against HHPA and displayed both rhinitis and contact urticaria (the face and neck). The worker's skin symptoms were evidently due to airborne contact, since she had not had any skin contact with liquid epoxy resin or mixtures of MHHPA and HHPA. These urticaria symptoms were confirmed by a 20-min closed patch test for MHHPA, but not by that for HHPA. The causative agent was considered to be MHHPA, although the specific IgE determination to MHHPA was not performed.     

三种高填料型流动树脂用于后牙区充填的体外研究

目的探讨高填料型流动树脂用于后牙承力区充填的可行性。方法根据ISO4049标准制备试件,采用电子式万能试验机测试材料的挠曲强度;动态超显微硬度仪测试材料的硬度;用四种树脂以不同方式充填后牙Ⅱ类洞,并用亚甲基蓝色染色法测试材料的微渗漏情况。结果挠曲强度的大小顺序为:BFPBFP≈LV2>SDR,Z350与SDR、LV2、BFP间硬度比较,差异均有统计学意义。七种充填方式中,SDR+Z350充填产生的微渗漏较大。结论高填料型树脂LV2、BFP的机械性能与传统型复合树脂Z350相似,可达到牙合面修复材料的要求;高填料型流动树脂垫底具有优越性。     

多孔细菌纤维素-聚乳酸乙醇酸复合支架制备及性能研究

目的制备多孔细菌纤维素(Bacterial Cellulose,BC)-聚乳酸乙醇酸(Poly Lactic-co-gly-colic acid,PLGA)复合支架及研究其相关性能。方法溶液浇铸/粒子沥滤技术制备多孔BC-PLGA复合支架并检测相关理化性能(抗张强度、断裂伸长率、吸水率和孔隙率)。然后接种成骨样细胞MG-63体外培养,通过扫描电镜(SEM)观测细胞生长状况;四甲基偶氮唑盐比色法(MTT)分析支架浸提液毒性。结果多孔BC-PLGA支架抗拉强度为(9.8536±0.9155)N/mm2,伸长率为(596.16±81.51)%,孔隙率为(65.11±5.72)%,吸水率为(69.42±5.13)%;扫描电镜和MTT法检测结果显示支架无细胞毒性,对MG-63细胞具有良好的亲和性及增殖活性。结论多孔BC-PLGA复合支架具备良好的理化性能和生物相容性,有望用作组织工程支架材料。