Effect of self-ligating bracket appliance on the periodontal tissues in patients with chronic periodontitis after orthodontic treatment

Objective:To explore the effect of self-ligating bracket appliance on the periodontal tissues in patients with chronic periodontitis after orthodontic treatment.Methods:A total of 56 patients with chronic periodontitis who were admitted in our hospital were included in the study and divided into the observation group and the control group according to different treatment protocols. The patients in the observation group were given self-ligating brackets, while the patients in the control group were given traditional brackets. The periodontal tissues and tooth motility (TM) before and after treatment in the two groups were observed and recorded. IL-1βand TNF-α levels in the gingival crervicular fluid (GCF) before and after treatment in the two groups were detected.Results:PD, CAL, SBI, and PLI after treatment in the two groups were significantly reduced, while GR was significantly elevated when compared with the control group. PD, CAL, SBI, and PLI after treatment in the observation group were significantly lower than those in the control group, while GR was significantly higher than that in the control group. TM after treatment in the two groups was significantly improved, among which the number of 0° TM was significantly increased, while the number ofⅠ°-Ⅲ°TM was significantly reduced. IL-1β and TNF-α levels in GCF after treatment in the two groups were significantly reduced when compared with before treatment. IL-1β and TNF-α levels in GCF after treatment in the observation group were significantly lower than those in the control group.Conclusions:The self-ligating brackets can effectively improve the periodontal tissues and TM in patients with chronic periodontitis, and reduce the levels of inflammatory cytokines in periodontal tissues, with an accurate efficacy.

External apical root resorption and the release of interleukin-6 in the gingival crevucular fluid induced by a self-ligating system

The aim of this study was to investigate the amount of external apical root resorption (EARR) and the release of interleukin (IL)-6 in the gingival crevicular fluid (GCF) in subjects treated with a low-force low-friction system. Sixty patients were assigned to two groups of thirty patients for each: one group received treatment with self-ligating brackets and the other with conventional ligated edgewise brackets. All patients were treated with extraction of the maxillary first premolars. The EARR of the maxillary central incisors was evaluated on the periapical radiographs and cephalograms, taken before and after orthodontic treatment. The GCF was also collected non-invasively from the mesial and distal sides of central incisors by using filter paper strips before and after orthodontic treatment. Enzyme-linked immunosorbent assay (ELISA) kits were used to determine the IL-6 levels in the GCF samples. A significant difference was found in the amount of EARR between the patients with self-ligating brackets and conventional brackets. The mean amount of EARR was significantly lower for self-ligating brackets than conventional brackets (p < 0.05). The GCF levels of IL-6 for the patients with self-ligating brackets appliance were significantly lower than for those with the conventional brackets (p < 0.05). These results show that the mean amount of EARR and the GCF levels of IL-6 were significantly lower in the patients treated using low-force low-friction appliances than conventional brackets. Therefore, self-ligating brackets may be a useful system for reducing inflammation and EARR.

An Eight Component Integrable Hamiltonian Hierarchy from a Reduced Seventh-Order Matrix Spectral Problem

We present an eight component integrable Hamiltonian hierarchy, based on a reduced seventh order matrix spectral problem, with the aim of aiding the study and classification of multicomponent integrable models and their underlying mathematical structures. The zero-curvature formulation is the tool to construct a recursion operator from the spatial matrix problem. The second and third set of integrable equations present integrable nonlinear Schrödinger and modified Korteweg-de Vries type equations, respectively. The trace identity is used to construct Hamiltonian structures, and the first three Hamiltonian functionals so generated are computed.

广义n-omni-李代数胚

本文研究广义n-omni-李代数胚结构。首先,在直和丛D_(0)^(N)E⊕JE上定义D^(n-1)值配对和高阶Dorfman括号,构造广义n-omni-李代数胚,证明广义n-omni-李代数胚具有与n-omni-李代数胚类似的性质。其次,当E为平凡线丛时,构造截面Γ(ε^(n))上的高阶Dorfman括号,得到与平凡线丛_(M×R)相关的广义n-omni-李代数胚ε^(n)_(M×R)。最后,给出广义n-omni-李代数胚高阶Dirac结构,并证明图Gr(B_(△))为广义n-omni-李代数胚的高阶Dirac结构。

塔克拉玛干沙漠光伏电站防风固沙解决方案浅析

为研究流动沙漠地区光伏电站如何进行防风固沙的问题,以塔克拉玛干沙漠的光伏电站为研究对象,采用流动沙漠地区种植草方格的防风固沙方法,以及专项光伏支架和基础设计方法对流动沙漠地区光伏电站防风固沙的可行性解决方案进行了分析。分析结果表明:通过在光伏场区围栏外、光伏场区内道路两侧、光伏箱逆变器一体机基础外围、光伏支架桩基周边、升压站围墙四周内种植草方格进行固沙,可以降低风沙流穿过光伏电站的风速,减缓流动沙漠的迁移速度;采用螺旋钢管桩和前后双立柱结构光伏支架与种植草方格相结合的方案,可以有效缓解流动沙漠地区风力作用对光伏支架基础的侵蚀问题,有效预防光伏支架基础周围出现“沙窝”现象。研究结果可为流动沙漠地区光伏电站的防风固沙设计方案提供参考。

MABS工作机理计算机模拟

MABS主要是通过其内部的弹性囊在制动压力下的变形而起作用。根据MABS弹性囊腔的压力一体变形特性和流体力学理论建立了MABS的数学模型，并以此通过计算机模拟计算了制动系统装MABS与不装MABS的制动过程中的压力变化情况。

棉花苞叶三维形态可视化建模研究

通过数字图像处理技术,获取棉花苞叶器官的边缘和中脉坐标点,并从中提取边缘和中脉的控制点;设计过控制点的B样条曲线插值算法,模拟并重建了苞叶器官的边缘框架,经Delaunay三角化和纹理贴图实现了棉花苞叶器官三维形态的可视化表达。

盘式制动器瞬态温度场的计算与分析

用有限单元法来建立盘式制动器瞬态温度的理论计算模型，编制了相应的计算程序。以１２５型摩托车用制动器为例，计算和分析了一次制动工况下的瞬态温度场，阐明了它的温度特征。

鼓式制动器制动尖叫的机理及其预防

本文通过对具有领从蹄结构的鼓式制动器进行试验研究及谱分析，发现制动系统的切向振动是鼓式制动器制动尖叫的主要振源，通过建立制动尖叫的力学模型，较好地解释了制动尖叫产生的机理，本文进一步推导了制动过程中的切向力激振频率计算公式。只要在通常的制动工况下能使该激振频率避开结构的共振频率，则制动器在制动过程中就不会产生制动尖叫．因此，根据该方法可在设计阶段对制动器的制动尖叫进行预测，从而为预防制动器制动尖叫提供设计依据。

用Pro/E和ANSYS对火箭橇载三轴转台进行建模及模态分析

用Pro/E和ANSYS软件对三轴飞行模拟转台的底座进行了建模、模态分析,得出了该零件的二阶模态图,为火箭滑车载三轴转台模型的改材及电机和轴承的选型提供了详实可靠的数据。

基于Solidworks和ANSYS Workbench的剪叉式拖车拖架分析优化

以一种新型的剪叉式拖车的拖架装置为研究对象,利用Solidworks软件拖架装置进行参数化建模,然后导入ANSYS Workbench软件模拟拖架的受载情况,得到应力与变形分布云图;对拖架进行了拓扑优化和目标驱动优化,为后续对剪叉式拖车整体设计提供了参考。

采准掘进巷道顶板支护技术研究

对现代煤矿企业中采准掘进巷道的特点进行了诠释,分析了矿山压力对采准掘进巷道的影响,着重介绍了煤矿业中常见的几种顶板支护技术,并配合图形表格说明了这几种顶板支护技术所要遵循的质量标准。

基于SVPWM的数字化低频电源

低频电源是矿井交流提升减速和爬行阶段最重要的电气设备。介绍一种利用IGBT设计的数字化低频电源。该电源利用SVPWM控制使低频输出线电压较正弦波调制时提高15%,克服了正弦波输出电压不足,低频制动力矩小的缺点,并设计了能量回馈逆变桥,使电机发电运行时能量回馈电网,实现了电机的四象限运行。另外,与晶闸管低频电源相比,该电源具有体积小、重量轻、效率高、谐波小的优点。

水轮发电机下机架振动模态和径向谐响应分析

本文以三板溪水轮发电机为例,给出了水轮发电机下机架径向谐响应分析的过程和方法,为产品设计提供了技术支持。

我国钻井装备的技术进展——系列专题之五

文章回顾了我国钻井装备的发展历程 ,列举了六大钻机制造公司 (厂 )的产品及其主要性能 ,重点介绍了交流变频电动钻机、液压盘式刹车、顶部驱动钻井装置和单轴绞车等方面的技术进展、钻井工艺要求和装备组成。说明我国钻机制造业在“九五”期间已经奠定了坚实的基础 ,预期在“十五”期间及其以后必将在与国际接轨方面取得重大突破。

隐适美MA治疗青少年骨性Ⅱ类下颌后缩患者导下颌向前的矫治效果

目的:观察隐适美MA对青少年骨性Ⅱ类下颌后缩患者的应用价值及导下颌向前的矫治效果。方法:选取2017年7月-2019年7月本院治疗的40例青少年骨性Ⅱ类下颌后缩患者作为研究对象。按照随机数字表法分为观察组和对照组,各20例。观察组予以隐适美MA治疗,对照组予以Twin-block双合垫矫治器治疗。对比两组牙齿功能(语言功能、咀嚼功能及吞咽功能)评分、口腔健康影响程度量表(OHIP)评分,以及观察组治疗前后上牙槽座角(SNA)、下牙槽座角(SNB)、上下牙槽座角(ANB)、下颌平面角(GoGn-SN)、APDI值、ANS-Me。结果:观察组治疗后语言功能、咀嚼功能及吞咽功能评分依次为(4.35±0.30)、(4.33±0.39)、(4.29±0.36)分,高于对照组的(3.23±0.40)、(3.59±0.39)、(3.58±0.46)分,差异有统计学意义(P<0.05)。治疗后,观察组牙齿功能评分均高于对照组,差异有统计学意义(P<0.05)。治疗后两组OHIP量表各指标评分均较治疗前降低,观察组明显低于对照组(P<0.05)。治疗后,观察组SNB、APDI值、ANS-Me较治疗前明显增加、ANB明显缩小(P<0.05)。结论:青少年骨性Ⅱ类下颌后缩患者采用隐适美MA治疗,不仅可以改善患者牙齿功能,还可以在一定程度上诱导患者下颌向前,改变患者侧貌,效果显著,可以在临床推广使用。

新立油田扶杨油层油藏特征研究

新立油田处于松辽盆地中央坳陷区最西端,扶杨油层包括扶余油层以及杨大城子油层,油层厚度约500 m,是新立油田主要目的层。通过岩心、测井、录井、钻井、试油以及PVT资料的研究,对油藏的构造、沉积、储层、油层展布有系统性认识。研究认为,储层物性条件差,孔隙度与渗透率都很低;油层分布范围广,平面连通性好,但单井有效厚度差异大,主体中心区厚度较大,并向周边逐渐减薄。油藏的控制因素由于方向的不同而不同:东西向油藏主要受到构造和断层因素控制,形成构造油藏以及断块油藏;南北向油藏含油范围与构造范围分布不统一,主要受岩性控制,发育有岩性油藏。新立油田扶杨油层整体属于构造——岩性油藏。在未来的工作中,要加大沉积预测以及地震方面的研究,从而形成综合性的地震地质分析和一套切实可行的预测含油有利区的方法。

矿井主提升设备事故浅析

通过对矿井主提升设备事故发生的原因进行多方面的分析和研究,从系统维护、设备制造、工程设计和规范编制等方面提出了改进措施和建议,以避免类似事故的发生。

带再生制动的电动车辆斩波器的研究

介绍一种带再生制动的电动车斩波器系统,给出了设计方案,分析了工作原理.实验结果表明:该系统电路简单,工作可靠,性能优良。

不同前牙转矩DamonQ自锁托槽的临床应用

目的:探讨不同前牙转矩DamonQ自锁托槽的临床使用方法。方法:用不同转矩DamonQ自锁托槽技术矫治各类病例80余例,其中安氏I类43例,安氏Ⅱ类27例,安氏Ⅲ类15例。结果:治疗后所有患者上下牙列排列整齐,覆牙合、覆盖正常,磨牙尖牙关系中性;通过牙根移动,改变切牙倾度,软组织侧貌改善明显;减少了矫治后期需要对切牙的转矩控制所消耗的时间。结论:选择合适转矩的DamonQ自锁托槽是一种简便、有效的控根方法,使切牙美观和功能得到进一步改善。