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.

2种不同类型自锁托槽对前牙转矩控制的对比研究

目的比较主动和被动自锁托槽在拔牙病例中对前牙转矩的控制。方法选取40例拔牙病例,20例应用Empower自锁托槽,20例应用Damon自锁托槽,对治疗前后反应骨性指标的SNA、SNB、ANB、MP-SN和上下前牙倾斜度的牙性指标:UISN、U1-PP、U1-NA、L1-NB、L1-MP进行头影测量分析,应用SPSS 13.0软件对治疗前后测量的结果进行分析。结果两组病例治疗前各项测量项目无明显差别;两组病例治疗前后骨性指标无明显改变,而牙性指标UI-SN、U1-PP、U1-NA、L1-NB、L1-MP都有明显减小;Empower组病例治疗后UI-SN、U1-PP、U1-NA测量值较Damon组大,有显著性差异(P<0.05),而Empower组L1-MP治疗后测量值较Damon组小,结果有显著性差异(P<0.05),Empower组L1-NB治疗后测量值较Damon组小,但无统计学差异(P>0.05)。结论主动自锁托槽在拔牙病例中对前牙转矩的控制较被动自锁托槽理想。

稀土镁合金薄腹高筋支架的等温锻造技术

针对Mg-9Gd-3Y-0.6Zn-0.5Zr合金薄腹高筋支架构件,设计其等温锻造成形方案和模具装置。采用有限元软件DEFORM-3D对薄腹高筋支架等温成形过程进行有限元模拟和实验,分析模具结构和成形方案对成形过程中金属流动充填的影响规律,揭示缺陷产生原因,并进行工艺优化,最终成形出质量良好的锻件。结果表明,采用分瓣模具结构和等温成形技术,可整体一次性精密成形形状复杂的薄腹非对称高圆弧筋类锻件,且构件组织细小均匀;通过设置工艺圆角和增加活动阻尼块的方式,可有效控制薄腹高筋支架圆弧筋处金属的流动充填阻力,消除圆弧筋抽料和侧耳充不满缺陷。

主动、被动自锁托槽摩擦力的meta分析研究

目的采用meta分析的方法评价主动自锁托槽与被动自锁托槽摩擦力的大小。方法检索Pubmed、荷兰医学文摘(Embase)、Google文献检索、中国期刊网(CNKI)和中国生物医学文献数据库(CBMdisc)数据库,搜集从建库至2011年9月公开发表的关于主动、被动自锁托槽摩擦力的随机对照实验。利用Revman4.2软件及Stata 7.0软件对纳入meta分析的研究进行定量分析,以评价主动、被动自锁托槽与不锈钢丝结合时滑动摩擦力的大小。结果有6项研究适合做meta分析。结果显示:主动、被动自锁托槽在与圆丝结合时,摩擦力的大小没有统计学差异;而与不锈钢方丝结合时主动自锁托槽的摩擦力大于被动自锁托槽,差异具有统计学意义。结论在矫治初期,主动、被动自锁托槽摩擦力没有统计学差异,而在矫治后期,主动自锁托槽摩擦力大于被动自锁托槽。

高精度仪器高量取方法研究

各种工程对测量的精度要求越来越高,仪器高的量取是测绘中的首要程序,仪器高的精度决定了测量外业的整体精度。本文介绍了量取仪器高的一般方法,并在对现有三脚架作出局部改动的基础上,配对一种新设计的尺子,提出了一种新的仪器高量取方法。该方法操作简便,可行性强,可提高仪器高的测量精度,具有很强的普及性。本文的设想为测量工作中仪器高的量取提供了新的参考,也为仪器改良提供了新的思路。

无托槽隐形矫治对牙周炎正畸患者龈沟液及血清PGE2、sICAM-1、ALP、PAK5的影响

目的:探讨无托槽隐形矫治对牙周炎正畸患者龈沟液及血清前列素E2(prostE2,PGE2)、可溶性细胞间黏附分子-1(soluble intercellular adhesion molecule-1,sICAM-1)、碱性磷酸酶(alkaline phosphatase,ALP)、p2l活化激酶(p21 activated kinase,PAK5)的影响。方法:88例牙周炎正畸患者,按随机数字表法分为对照组(n=41)和研究组(n=47),对照组予以直丝弓矫治器治疗,研究组予以无托槽隐形矫治。比较两组临床疗效,治疗前后龈沟液及血清PGE2、sICAM-1、ALP、PAK5水平,牙周状态及安全性发生情况。结果:研究组和对照组总有效率比较,无统计学差异(P>0.05)。治疗前,两组龈沟液及血清PGE2、sICAM-1、ALP、PAK5水平比较无统计学差异(P>0.05);治疗后,两组龈沟液及血清PGE2、sICAM-1、ALP、PAK5水平均上升,研究组低于对照组(P<0.05)。研究组菌斑指数(PLI)、牙龈沟出血指数(SBI)、牙龈指数(GI)、牙周袋探针深度(PD)、临床附着丧失(CAL)低于对照组(P<0.05),两组不良反应发生情况比较无统计学差异(P>0.05)。结论:无托槽隐形矫治对牙周炎正畸患者的疗效确切,对龈沟液及血清PGE2、sICAM-1、ALP、PAK5的影响较小,有利于矫治期间的口腔卫生维护。

数学形态学与主动轮廓模型的托槽焊膏图像检测算法

针对牙齿矫正托槽加工中的焊膏残留问题,提出一种数学形态学和主动轮廓模型的托槽焊膏图像检测算法。首先对三原色(RGB)彩图进行R-B灰度化处理,并进行灰度图阈值分割;然后对二值图进行数学形态学操作,去除噪声并提取托槽区域彩图。对托槽彩图进行色度,饱和度,纯度(HSV)转换,用主动轮廓模型对H分量进行分割。将托槽作为初始分割范围,再利用循环伏安(CV)模型分割出焊膏。试验结果表明:提出的算法目标定位能力强,能很好地提取焊膏目标,Jaccard相似度(SD)指数、正确率、错分率、漏分率分别为83.41%,90.96%,16.97%,2.43%。

连续梁悬臂牛腿病害无损主动加固技术

针对某连续梁桥悬臂牛腿出现斜向受力裂缝和下挠变形较大的病害,提出一种增设刚性梁对梁体牛腿端进行部分卸荷的主动加固方法。该方法通过在牛腿位置处的墩顶增设刚性梁,将悬臂牛腿的支座竖向力直接通过刚性梁端部传递到墩顶,以分担悬臂牛腿的部分荷载,减小悬臂牛腿受力。施工中,通过整体同步提升技术将刚性梁准确安装到预定位置,采用PLC同步顶升高精度控制技术完成悬臂牛腿部分荷载转移到刚性梁上的体系转换,达到主动分担悬臂牛腿荷载的目的。监控和荷载试验结果显示,刚性梁与悬臂牛腿整体受力性能良好,显著减轻了原主梁牛腿的负载,提高了牛腿结构的安全储备。

不同自锁托槽对切牙牙根外吸收影响的临床对比研究

目的:评价运用不同自锁托槽对正畸治疗中牙根外吸收的影响。方法:选取南京同仁医院口腔科36例非减数治疗安氏Ⅰ类均角错畸形患者,分为主动自锁托槽组和被动自锁托槽组,根据正畸治疗前后全口曲面断层片和记存模型,测量计算出治疗前后切牙的全长和不同自锁托槽组间牙根外吸收量,进行统计学检验,分析不同自锁托槽对切牙牙根外吸收的影响。结果:主动自锁托槽组的牙根外吸收量略大于被动自锁托槽组的牙根外吸收量,但差异无统计学意义(P>0.05)。结论:不同自锁托槽均可造成切牙根吸收,但主动自锁托槽对非减数安氏Ⅰ类错颌畸形治疗过程中牙根吸收的影响与被动自锁托槽相比有增加趋势,但无统计学差异。

大采高综采面顶板活动规律及支架适应性研究

为研究山西长平煤矿Ⅲ4308大采高工作面顶板活动规律及合理的工作阻力,采用理论分析和现场实测的手段,分析了大采高工作面顶板活动规律,得到了支架的合理工作阻力,并验证了所选支架的适应性。结果表明,Ⅲ4308工作面基本顶初次来压步距为30 m,周期来压步距为15 m,工作面所需的支护阻力为10.26 MN,79.56%的液压支架处于增阻和恒阻的状态,ZY12000/28/62D型大采高液压支架可以满足工作面生产要求。