新型Ti-Fe-Mo-Mn-Nb-Zr系钛合金的力学性能

在纯钛中加入Fe,Mo,Mn,Nb和Zr强化元素制成新型Ti-Fe-Mo-Mn-Nb-Zr系钛合金,测定了该材料的硬度、压缩强度及弹性模量等性能,考察了加入元素对硬度、压缩强度的影响规律.实验结果表明该合金形成了等轴α+β组织,与其它现有牙科用钛合金相比,硬度、弹性模量更接近牙本质的,且压缩性能明显优于其它牙科用钛合金.     

Rewired Cellular Metabolic Profiles in Response to Metformin under Different Oxygen and Nutrient Conditions

Metformin is a metabolic disruptor, and its efficacy and effects on metabolic profiles under different oxygen and nutrient conditions remain unclear. Therefore, the present study examined the effects of metformin on cell growth, the metabolic activities and consumption of glucose, glutamine, and pyruvate, and the intracellular ratio of nicotinamide adenine dinucleotide (NAD⁺) and reduced nicotinamide adenine dinucleotide (NADH) under normoxic (21% O₂) and hypoxic (1% O₂) conditions. The efficacy of metformin with nutrient removal from culture media was also investigated. The results obtained show that the efficacy of metformin was closely associated with cell types and environmental factors. Acute exposure to metformin had no effect on lactate production from glucose, glutamine, or pyruvate, whereas long-term exposure to metformin increased the consumption of glucose and pyruvate and the production of lactate in the culture media of HeLa and HaCaT cells as well as the metabolic activity of glucose. The NAD⁺/NADH ratio decreased during growth with metformin regardless of its efficacy. Furthermore, the inhibitory effects of metformin were enhanced in all cell lines following the removal of glucose or pyruvate from culture media. Collectively, the present results reveal that metformin efficacy may be regulated by oxygen conditions and nutrient availability, and indicate the potential of the metabolic switch induced by metformin as combinational therapy.     

Applications of Plasma-Activated Water in Dentistry: A Review

The activation of water by non-thermal plasma creates a liquid with active constituents referred to as plasma-activated water (PAW). Due to its active constituents, PAW may play an important role in different fields, such as agriculture, the food industry and healthcare. Plasma liquid technology has received attention in recent years due to its versatility and good potential, mainly focused on different health care purposes. This interest has extended to dentistry, since the use of a plasma–liquid technology could bring clinical advantages, compared to direct application of non-thermal atmospheric pressure plasmas (NTAPPs). The aim of this paper is to discuss the applicability of PAW in different areas of dentistry, according to the published literature about NTAPPs and plasma–liquid technology. The direct and indirect application of NTAPPs are presented in the introduction. Posteriorly, the main reactors for generating PAW and its active constituents with a role in biomedical applications are specified, followed by a section that discusses, in detail, the use of PAW as a tool for different oral diseases.     

A systematic method for predetermined scanning electron microscope analysis in dental science

Scanning electron microscope evaluation could be criticized if the method adopted to correct for bias is not specified in the study design. Observers can draw conclusions from images unconsciously chosen to best support their research hypotheses, impairing the basic research principle of operator's impartiality. In this study, a systematic observation method has been described and verified for repeatability. The number and the observation points on a certain specimen have been predetermined using a scheme along with observation rules previously established in the research protocol. When our instrument is used at an operating magnification between 500× and 1,000× (corresponding to a frame of 250×190 µ and 120×90 µ, respectively), the method allowed 100% repeatable observation frames, with linear frame errors in finding an observation point of 12.5% in length and 16.8% in height. With modifications to accommodate research objective and statistical requirements, the method could be applied to many SEM observation study. SCANNING 32: 97–103, 2010. © 2010 Wiley Periodicals, Inc.     

牙科光固化复合树脂材料的性能与展望

牙科光固化复合树脂具有色泽美观,强度高,临床操作方便,粘结固位效果好等优点,在牙科修复领域引起了广泛关注.该复合材料是由树脂基体、无机填料和光引发体系组成的,原料混合后经特定波长的可见光照射即可固化.牙科光固化复合树脂虽然已在临床上得到了应用,但在性能方面仍然存在某些不足之处,所以如何进一步提高其性能成为目前研究的热点之一.该文作者综述了树脂基体、无机填料和光引发剂的研究情况,对光固化复合树脂的力学性能、聚合度、吸水性和溶解性等性能及其影响因素进行了评述,并对今后的研究进行了展望.     

牙科照明用异型微结构玻璃光纤棒的研究

针对传统牙科照明用光纤柔软易折断,装配难度大,端面易浸入血水造成交叉感染,敛集率低,光传输效率低等问题,研发了一种异型微结构玻璃光纤棒作为牙科照明手机内的通光元件,在装配、消毒、通光率等方面与传统牙科照明光纤做对比后证实刚性异型微结构玻璃光纤棒易于装配,耐医用高温高压消毒,且端面致密,抵制血水浸入;并在多次高温高压消毒后依然具备很高的光传输效率。     

The effect of radiopacifiers agents on pH,calcium release,radiopacity, and antimicrobial properties of different calcium hydroxide dressings

The aim of this study was to evaluate the antimicrobial activity, pH level, calcium ion release, and radiopacity of calcium hydroxide pastes associated with three radiopacifying agents (iodoform, zinc oxide, and barium sulfate). For the pH and calcium release tests, 45 acrylic teeth were utilized and immersed in ultrapure water. After 24 h, 72 h, and 7 days the solution was analyzed by using a pH meter and an atomic absorption spectrophotometer. Polyethylene tubes filled with the pastes were used to perform the radiopacity test. For the antimicrobial test, 25 dentin specimens were infected intraorally in order to induce the biofilm colonization and treated with the pastes for 7 days. The Live/Dead technique and a confocal microscope were used to obtain the ratio of live cells. Parametric and nonparametric statistical tests were performed to show differences among the groups (P < 0.05). The pH analysis at 7 days showed significant differences (P < 0.05) among the groups. No differences among the pastes were found in the calcium release test on the 7th day (P > 0.05). The calcium hydroxide/iodoform samples had the highest radiopacity and antimicrobial activity against the biofilm‐infected dentin in comparison to the other pastes (P < 0.05). Calcium hydroxide mixed with 17% iodoform and 35% propylene glycol into a paste had the highest pH, calcium ion release, radiopacity, and the greatest antimicrobial action versus similar samples mixed with BaSO4 or ZnO. Microsc. Res. Tech. 78:620–625, 2015. © 2015 Wiley Periodicals, Inc.