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.

浅谈正畸临床矫治新技术——球托止动定位轻力5s系统

达成精确的转矩表达和稳定的支抗控制是正畸治疗的关键因素,患者在治疗过程中对口腔健康与矫治感受的重视程度日益增长,球面自锁托槽(球托)在一定程度上满足了这两个方面的需求。球面自锁托槽的球面结构可以降低因佩戴矫治器而引起口腔溃疡的概率,并能减少生物膜附着,降低牙龈和牙周疾病的发生概率。与方形托槽相比,球面自锁托槽的脱落率降低了95%。止动定位系统是球面自锁托槽的核心创新点,主要由螺纹系统、螺丝系统和弓丝系统组成。得益于止动定位系统,球面自锁托槽可以去除余隙角,精准表达转矩,使用止锁螺丝时可增强支抗稳定性。止动定位系统搭配了3种特制的细方丝(0.1524 mm×0.6350 mm、0.2032 mm×0.5842 mm、0.2540 mm×0.5588 mm),用轻力排齐的同时可以表达转矩,控制牙根。球托矫治器以黏膜刺激小、脱落率低、转矩表达精准、支抗保有率高、细方丝轻力矫治等特点引起了广泛关注。

球面托槽和传统托槽作用下口腔黏膜的生物力学研究

目的通过三维有限元分析在球面托槽以及传统托槽的作用下口腔黏膜的力学反应。方法建立上唇组织-中切牙-托槽的三维有限元模型。根据中切牙不同排列情况设计4个模拟案例,分析滑动的上唇组织分别在球面托槽以及传统托槽作用下的应力、应变情况。结果牙齿平齐时,球面托槽对口腔黏膜的最大应力较传统托槽大;切牙发生近中扭转15°、30°以及唇侧倾斜15°时,传统托槽情况下口腔黏膜最大应力均大于球面托槽最大应力。结论具有圆滑外形的球面托槽比方形传统托槽更契合牙列不齐正畸患者口腔软组织的功能运动,建议改善方形托槽的外形设计以降低口腔黏膜组织的力学反应。

战车用惯性定位定向系统的支架误差分析及补偿

战车用惯性定位定向系统由于采用双轴陀螺平台结构,不可避免地存在着支架误差,从而影响系统航向精度。应用球面三角法和方向余弦矩阵法分别推导出双轴陀螺平台的支架误差公式,发现由这两种方法推导出来的公式计算结果是一致的。最后通过数学仿真和分析,给出了支架误差与载体的姿态角之间的定量关系。根据此误差公式,对惯性定位定向系统的航向输出能够进行误差补偿,从而保证了动态条件下定位定向系统的航向输出精度。

止锁扩弓非拔牙矫治技术治疗重度牙列拥挤1例并文献复习

目的探讨球面自锁托槽止锁扩弓非拔牙矫治技术治疗重度牙列拥挤的效果。方法安氏Ⅰ类错[牙合]重度牙列拥挤患者1例,应用球面自锁托槽止锁扩弓非拔牙矫治技术进行扩弓,测量矫治前后上下颌牙弓宽度、下颌3、4、5、6牙位的冠中心(FA)点距离、下颌WALA嵴宽度以及下颌4、5、6牙位FA点-WALA嵴距离。结果矫治7个月时,患者牙列拥挤解除,牙弓形态良好。上下颌牙弓宽度较矫治前均有所增加,尤其4-4牙位间宽度增加最为明显;FA点距离及WALA嵴宽度均增加,FA点-WALA嵴距离接近正常值;前牙唇倾量不大。结论球面自锁托槽止锁扩弓非拔牙矫治技术可有效解除重度牙列拥挤,排齐牙列。

不同支柱连接结构球罐对比研究

利用有限元分析软件ANSYS对4 000 m^3大型球罐进行整体建模,对其在不同操作工况下进行应力分析,并通过对长圆形连接结构、U形柱结构、托板结构三种支撑形式在最危险工况下的受力对比,找出最优的支撑结构。

苏州360剧场大跨度钢桁架设计研究

苏州360剧场为表演区与观众区合为一体的新颖剧院。通过多方案比选,剧场屋面采用大跨单向钢结构桁架体系,上承幕墙层钢结构骨架。利用SATWE及SAP2000等结构软件,按整装模型、单独模型进行总体指标、构件应力及变形等计算分析,验证了大跨重载屋面钢桁架采用两端铰接的合理性,明确了支承框架柱及转换托架的设计思路和抗震性能要求,提出了幕墙层骨架与主体钢结构考虑模拟施工顺序一体化设计理念;同时分享了固定球型支座选用及节点构造等设计研究成果。结果表明结构选型安全可靠、受力合理。

浅析硫酸干吸塔塔底封头支座处局部应力计算与校核

参考球壳局部应力计算方法,以工程实际中1台吸收塔为例,浅析了硫酸干吸塔塔底支座处封头局部应力的计算方法,并按照应力分析方法进行了校核,可供硫酸干吸塔塔底采用支承式支座设计时参考。

一种用于球面阵T/R组件安装的新型支架

大型球面相控阵雷达安装的T/R组件数量众多,所用线缆数量更是T/R组件的数倍,导致雷达总体制造成本居高不下。为了降低雷达的总体成本,文中设计了一种用于球面相控阵雷达T/R组件安装的新型支架,并通过3D软件对新型T/R组件支架进行了仿真设计。新型支架能够很好地解决球面相控阵雷达T/R组件安装复杂、走线困难的问题,能有效降低结构加工成本和电缆成本,对后续工程实施有很大的启发。文中首先介绍了相控阵雷达的发展现状和面临的成本问题以及传统T/R组件支架存在的安装问题,然后阐述了新型T/R组件支架的组成和优势,最后探讨了球面相控阵雷达的发展趋势。

炼钢转炉托圈销轴孔在线修复探讨

主要对炼钢厂转炉托圈三点球面支撑座销轴孔损坏的原因分析以及在线修复的成功实施进行了阐述及总结,为炼钢行业同类型转炉托圈在线修复提供一定的技术支持与积累,供炼钢行业借鉴。