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。

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。

面向自动化物料传送的被动驱动托架设计与分析

针对现有的航天飞行器数字化装配生产线产品转运自动化、装配数字化的发展趋势,设计了一套兼容生产线全流程转运工作设备、适应多几何尺寸的托架。在分析作业现场产品转运流程、保证要求以及装配需求的基础上,提出了一种基于辊杠动力源的被动驱动托架总体设计方案,解析了托架关键受力部位和薄弱点,有针对性地开展了关键部件的设计、计算、校核,并使用专用软件开展了数值模拟分析与验证,托架试制完成后进行了工程试用。结果表明:关键部件的强度数值模拟值与理论设计计算值偏差在10%以内,位移形变均保持在0.1mm以下,验证了设计的准确性和合理性;工程使用阶段,托架的功能和性能均满足现场使用要求。

传统与被动自锁托槽扭转性能的有限元分析

目的运用三维有限元分析方法,分析传统托槽与被动自锁托槽扭转性能的差异。方法建立HX(国产传统系列)、MUT(3M Mini Uni Twin传统系列)、3M(3M被动自锁系列)、Damon Q(Ormco被动自锁系列)托槽及相应弓丝的三维有限元模型,模型装配后进行网格划分,参数设定,边界限定及力值加载,最后绘制力矩值图形进行分析。结果托槽相同时,扭转力矩值随弓丝尺寸增加而增加。弓丝尺寸相同时,HX托槽所得扭转力矩值最大,其次分别为MUT、3M、Damon Q。结论托槽的扭转性能与槽沟长度、结扎方式、弓丝尺寸等关系密切。传统结扎方式托槽扭转性能明显高于被动自锁托槽,且Damon Q托槽的扭转性能最差。

挠性支承对飞轮隔振系统性能的影响分析

飞轮的高速转子在运转过程中会激发微幅多频振动,对航天器的高精度姿态稳定控制产生不利影响.本文基于飞轮隔振系统结构,建立其动力学模型,并通过实验验证该被动隔振装置的固有模态.对增加挠性支承的飞轮隔振系统的数学模型,通过仿真分析隔振装置在挠性支承条件下对飞轮扰动的抑制效果,实验测试了不同挠性支承条件对飞轮隔振系统微振动特性的影响.结果表明,隔振装置在悬臂挠性支承条件下依然具有优异的隔振性能,挠性支承刚度的适当减弱有利于飞轮隔振系统抑制扰动;挠性支承刚度会降低飞轮隔振系统的二阶结构固有振动频率,但基本不影响其涡动特性.

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。