新型义齿软衬材料的Ames试验研究

本文报道用Ａｍｅｓ法检测了１种新型义齿软衬材料的致突变性，结果表明，经ＴＡ９７、ＴＡ９８、ＴＡ１００和ＴＡ１０２株测试的材料在平皿掺入试验中未诱发阳性反应，但是４个菌株所对应的突变剂均诱发了阳性突变，因此所测试的义齿软衬材料在本实验条件下无诱发突变作用。     

MWCNTs／PMMA复合材料制备及力学性能研究

目的：制备多壁纳米碳管（MWCNTs），并将其用于聚甲基丙烯酸甲酯（PMMA）增强，研究其力学性能变化。方法：用化学气相沉积（ChemicalVaporDeposition，CVD）法制备MWCNTs，将1mgMWCNTs均匀分散于15mL牙托水中，制备MwCNTs／PMMA复合材料，测试复合材料的力学性能，观察断面形貌。结果：制备出MWCNTs均匀分散的MwCNTs／PMMA复合材料，复合材料的拉伸强度、延伸率较对照组有显著提高（P〈0．05），弯曲强度与对照组相比无明显差异（P〉0．05）。复合材料断面可见碳管与树脂之间结合良好，MWCNTs均匀弥散分布在树脂基体中。结论：应用CVD法制备MWCNTs用于增强基托树脂，可有效改善其力学性能。     

超声波-化学沉淀法制备牙科纳米氧化铝陶瓷粉体

目的:制备分散性好,粒度均匀的纳米α-A l2O3粉体。方法:应用超声波-化学沉淀法,制备氢氧化铝前驱体,经900℃、1 000℃、1 100℃、1 200℃煅烧后测试粉体性能。结果:1 200℃煅烧得到的A l2O3粉体为α-A l2O3,其晶粒平均粒径为D202=31.44 nm。结论:以乙醇为反应溶剂,在低频超声波作用下可制备出分散性好、粒度均匀的纳米级α-A l2O3粉体。     

Vitapex用于乳牙根管充填的临床评价

目的探索适合乳牙根管充填治疗的材料.方法用两种根管充填材料对乳前牙进行根管治疗.实验组采用Vitapex糊剂充填,对照组采用常规碘仿氧化锌糊剂(简称碘仿糊剂)充填,均跟踪观察疗效.结果实验组平均有效率为93.4%,对照组平均有效率为69%.实验组疗效优于对照组(P<0.05).结论Vitapex糊剂适合作乳牙根管充填材料.     

Scanning electron microscopic evaluation of the material interface of adjacent layers of dental materials

Objective

Many dental materials are used in contact with each other in sandwich techniques. Liners, bases and permanent restorative materials are placed adjacent to each other and allowed to set under the same conditions. The same applies for endodontic materials where irrigating solutions and root canal dressings come in contact with root canal obturating materials and root-end fillers. The aim of this research was to investigate the material interface of mineral trioxide aggregate (MTA) in contact with non-setting calcium hydroxide paste (CH), glass ionomer cement (GIC) and intermediate restorative material (IRM).

Methods

All materials were mixed according to manufacturer's instructions. Freshly mixed MTA (Dentsply) was placed in a plastic container and another dental material was compacted on it while still unset. These materials included GIC (Fuji IX), non-setting calcium hydroxide (Calasept) and IRM (Dentsply). The materials were allowed to set for 28 days at 37 °C and 100% humidity. The layered materials were sectioned longitudinally embedded in resin and polished to expose the interface between the two materials. Scanning electron microscopy (SEM) was performed of the interface and X-ray energy dispersive analysis (EDX) was conducted at 50 μm intervals to establish elements present at specific distances from the material interface.

Results

The calcium hydroxide paste did not affect the hydration of MTA. Migration of silicon, aluminum and bismuth from the MTA to the CH occurred. The GIC exhibited a high degree of micro-cracking and some porosity in the interfacial region. Strontium from the GIC was detected at 200 μm within the MTA. The zinc from the IRM cement was detected at 100 μm within the MTA. The zinc affected the hydration of the MTA leading to retardation of setting and increased porosity.

Conclusions

MTA interacts with other dental materials with resultant elemental migration in adjacent materials. Zinc oxide eugenol based cements should be avoided in the presence of MTA as zinc causes retardation of cement hydration with increased porosity. Glass ionomer cements absorb the water of hydration from the MTA also resulting in increased porosity and incomplete hydration of MTA.     

CORTISOMOL根管糊剂即时充填感染根管的临床观察

目的观察Cortisomol根管糊剂即时治疗感染根管伴急性根尖周炎的疗效。方法 门诊就诊的165例随机分为实验组(Cortisomol组)82例、91个牙和对照组(常规组)83例、87个牙。常规根管预备后,Cortiso-mol组即时行根管充填;对照组二次法常规根管充填。结果 实验组治疗后94.5％患牙3天内完全止痛,近期治愈率显著高于对照组(P<0.05)。结论 Cortisomol是一种理想的治疗感染根管的根管充填剂。     

Combination therapy of hydrogel and stem cells for diabetic wound healing

Diabetic wounds (DWs) are a common complication of diabetes mellitus; DWs have a low cure rate and likely recurrence, thus affecting the quality of patients’ lives. As traditional therapy cannot effectively improve DW closure, DW has become a severe clinical medical problem worldwide. Unlike routine wound healing, DW is difficult to heal because of its chronically arrested inflammatory phase. Although mesenchymal stem cells and their secreted cytokines can alleviate oxidative stress and stimulate angiogenesis in wounds, thereby promoting wound healing, the biological activity of mesenchymal stem cells is compromised by direct injection, which hinders their therapeutic effect. Hydro-gels form a three-dimensional network that mimics the extracellular matrix, which can provide shelter for stem cells in the inflammatory microenvironment with reactive oxygen species in DW, and maintains the survival and viability of stem cells. This review summarizes the mechanisms and applications of stem cells and hydrogels in treating DW; additionally, it focuses on the different applications of therapy combining hydrogel and stem cells for DW treatment.     

以一氧化氮为例浅析中医学“气”本质的研究思路

"气"作为中医学的一个基本概念,在病因病机阐述、临床诊断、治疗方法确定、方药选择、养生指导等多方面被广泛应用,但至今对于其本质的研究并未取得实质性进展。究其原因主要在于未能将具体的、物质的气完全从哲学概念中剥离出来。为此笔者作了初步探索,提出了气本质研究应当遵循的三大原则。并以一氧化氮为例,对三大原则进行了分析。同时笔者也初步提出了气本质的物质基础与一氧化氮密切相关,为中医气本质研究提供一个全新思路。     

A photo-switchable and thermal-enhanced fluorescent hydrogel prepared from N-isopropylacrylamide with water-soluble spiropyran derivative

Herein, a photo-switchable and thermal-enhanced fluorescent hydrogel has been fabricated from N-isopropylacrylamide (NIPAAm) with a mixture of water-soluble acryloyl-α-cyclodextrin/acryloyl-α-cyclodextrin-spiropyran (acryloyl-α-CD/ acryloyl-α-CD-SP) as cross-linkers. The physical properties, photochromic properties, and fluorescent behavior of the hydrogel were characterized. The fluorescence emission of the hydrogel can be reversibly switched ‘on/off’ by UV/visible light irradiation, and meanwhile the fluorescence intensity can be enhanced by increasing the temperature above the volume phase transition temperature (VPTT) of the hydrogel. The hydrogel also shows spatiotemporal fluorescent behavior, excellent cytocompatibility, and fatigue resistance in photochromic and photo-switchable fluorescent behaviors.     

Biomechanical evaluation of opening-wedge high tibial osteotomy with composite materials using finite-element analysis

Background

Medial opening-wedge high tibial osteotomy (HTO) has been used to treat osteoarthritis of the medial compartment of the knee. However, this makes the proximal tibia a highly unstable structure and causes the plate to be a potential source of mechanical failure. Consequently, proper design and material use of the fixation device are essential in HTO, especially for overweight or full-weight-bearing patients.