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.

Effect of Dietary Components on the Shear Bond Strength of Orthodontics Brackets after Thermal Aging

Introduction: The stability of orthodontic brackets throughout orthodontic treatment plays a critical role in the treatment’s effectiveness. The present in vitro study was designed to assess the impact of various dietary components on the performance of orthodontic brackets. Methods: Metal orthodontic brackets were bonded to 66 extracted anterior teeth divided into groups based on the solution type: Milk, Gatorade, Cold Coffee, and a control group using water. Each group consisted of 20 teeth except for the control group, which included six teeth. The bracketed teeth were submerged in their respective solutions for 15 minutes three times daily at different intervals to mimic an in vivo environment and were stored in artificial saliva at room temperature (23?C). The specimens underwent artificial aging through 10,000 cycles of thermocycling (representing one clinical year) between 5?C and 55?C. Shade measurements were taken using a VITA Easy Shade device, capturing the classic shade and L*, a*, and b* values. Delta E values were calculated immediately post-bonding and after 7 days, 1 month, 1, and 2 clinical years. The shear bond strength of each bracket was measured using an ultra-tester machine. Results: After two clinical years, significant differences in ΔE color values were observed across all groups, with the most substantial change noted in teeth immersed in cold coffee. Brackets submerged in milk demonstrated lower shear bond strength than other solutions, whereas the control group exhibited the highest shear bond strength (P = 0.01). Conclusion: The study indicates that dietary components significantly influence tooth color stability and the shear bond strength of orthodontic brackets, underscoring the importance of considering these factors in orthodontic treatment planning.

Application Strategies of the Bracket Set in Modern Architectural Design

The Bracket Set(dougong)is an important aspect of traditional Chinese architecture known for its exquisite structure,complexity,and rich variations.This design element has been used since the Qin and Han Dynasties and is still prevalent today.It highlights hierarchy and spiritual connotations in the design of a building.This article explores the application of Bracket Set elements in modern architectural design.It analyzes the specific application strategies of this design element,highlighting its value in modern architecture.The goal is to provide modern architectural designers with multiple perspectives and strategies to fully utilize the advantages of Bracket Set elements in architectural design and enhance the artistic value of their work.

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.

出踩与面宽方向柱头科斗栱抗震性能对比试验及数值分析

为研究加载方向对斗栱抗震性能的影响,文章基于地震作用的随机性和斗栱出踩与面宽方向的构造差异,对2个足尺柱头科斗栱分别沿出踩和面宽方向进行拟静力试验,得到斗栱的破坏模式、承载力、刚度与强度退化、耗能和变形能力。结果表明:斗栱在出踩和面宽方向分别加载时,大斗均相对平板枋滑移,馒头榫挤压剪断。出踩方向受力时单昂与桃尖梁相对滑移,面宽方向受力时整体明显转动。相比面宽方向受力的斗栱,出踩方向受力的斗栱具有更高的承载力、初始刚度和耗能能力,而变形能力较差。文章开展柱头科斗栱的数值分析,模拟结果与试验结果吻合较好,研究出踩和面宽不同加载方向、轴压荷载、木构件之间摩擦系数和木材弹性模量对其抗震性能的影响。结果表明:面宽方向是柱头科斗栱的最不利受力方向,其正负向承载力比出踩方向分别低19.21%和17.03%;轴压荷载和木构件之间摩擦系数越大,斗栱承载力越大,而木材顺纹弹性模量和横纹径向弹性模量对斗栱的初始刚度和承载力影响较小。

严寒地区光伏支架受力分析及优化

光伏支架作为光伏系统的重要组成部分,结构设计至关重要。为提升严寒地区光伏支架的安全性和经济性,采用有限元模拟方法对大庆市典型光伏工程进行了参数化分析和优化设计,主要探究檩条间距、立柱数量和前后立柱间距等不同结构参数对支架受力性能的影响。结果表明,支架挠度与檩条间距和立柱数量呈负相关,与前后立柱间距呈先增大后减小的趋势,临界荷载变化趋势与支架挠度变化趋势正好相反。并得出最佳优化方案:采用单块光伏板长度20%的檩条间距、斜梁水平投影60%的立柱间距、中间斜梁增加斜支撑和截面厚度2 mm的支架优化设计,此优化方案可使支架挠度降低71%。

无托槽隐形矫治器扩展上颌牙弓时附件差异对后牙位移的三维有限元分析

目的:利用全牙列精准扫描建模分析无托槽隐形矫治器扩展上颌牙弓时对后牙三维位移的影响。方法:选择2017年1月-2022年6月就诊于笔者医院口腔正畸科的86例成年患者为研究对象。所有患者均为安氏I类错牙合,矫治方案设计为仅通过邻面去釉的方式排齐上下前牙,在全牙列精准扫描建模的基础上,构建无托槽隐形矫治器进行上颌牙弓扩弓前以及扩弓后的后牙三维方向有限元模型的对比。结果:第5组位移量的最大值(3.315 17)与最小值(3.139 25)的比值均为所有组别中最小的。与其他组相比,第5组位移最小值与根尖的距离更近;第5组的第二前磨牙对应得到的等效应力值最小,应力的分布更为均匀。结论:施加附件作用时,对前磨牙的控根效果显著优于磨牙,其中优化后扩弓支持附件对后牙的控根效果更为优秀。

无褶皱吻合技术治疗结直肠恶性梗阻的应用价值

目的:探讨结直肠吻合新技术无褶皱吻合术治疗结直肠恶性梗阻的应用价值。方法:收集2020年1月至2022年12月收治的54例左半结肠直肠癌合并结直肠梗阻患者的临床资料。患者均为急诊就诊,确诊结直肠梗阻且腹部CT测量扩张肠管直径>30 mm。急症行内镜下经肛肠道自膨式金属支架置入术,术中取活检,病理结果证实恶性肿瘤。限期行腹腔镜结直肠癌切除术,术中应用无褶皱吻合技术进行一期吻合。术后随访7~24个月,评估吻合口相关并发症情况。结果:54例均完成腹腔镜结直肠癌切除术。术中测量近端肠管直径29.50~45.80 mm,平均(36.29±4.51)mm;远端肠管直径19.50~32.60 mm,平均(24.93±4.19)mm。近远端肠管管径不一致,行无褶皱吻合术,吻合放置抵钉座时间3~5 min,平均(3.80±0.79)min。术后无吻合口出血、狭窄、漏等并发症发生,术后随访未发生局部复发等远期并发症。结论:无褶皱吻合技术应用于结直肠恶性梗阻支架置入术后吻合确切,手术安全、可靠。

无托槽隐形矫治器治疗骨性Ⅱ类错[牙合]的疗效分析

目的 探讨无托槽隐形矫治器治疗骨性Ⅱ类错[牙合]的疗效。方法 以2021年7月至2023年10月在郑州大学第一附属医院进行正畸治疗的87例骨性Ⅱ类错[牙合]患者为研究对象开展回顾性分析,根据应用矫治器的不同分为传统组(应用传统固定矫治器治疗,n=44)和隐形组(应用无托槽隐形矫治器治疗,n=43)。比较两组矫治效果[采用美国正畸专家认证委员会(ABO)评级系统评定]、侧貌美学指标、牙周指数[探诊深度(PD)、菌斑指数(PLI)及牙龈指数(GI)]及龈沟液炎症因子[白细胞介素-1β(IL-1β)和可溶性细胞间黏附分子1(sICAM-1)]水平。结果 矫治后,隐形组ABO评级系统中的8项分值及总分与传统组比较,差异无统计学意义(P>0.05);矫治后,两组颌凸角、上下中切牙角、U1-PP、FMA、UL-EP、TLL-EP均优于矫治前(P<0.05),其中隐形组上下中切牙角、FMA优于传统组(P<0.05);矫治后,隐形组PD、PLI、GI及龈沟液IL-1β、sICAM-1水平均低于传统组(P<0.05)。结论 无托槽隐形矫治器可有效矫正骨性Ⅱ类错[牙合]畸形,提高患者侧貌美观度,并能减少对牙周组织的损害。

不锈钢支架熔模铸造工艺优化

通过ProCAST软件对除草机不锈钢支架进行熔模铸造的数值模拟,预测铸件缩孔缺陷分布情况,并对其浇注系统进行改善。利用正交试验对铸件的工艺参数进行研究,通过分析获得工艺参数的最佳方案。对该结果进行数值仿真以及实际铸造,发现铸件缺陷明显减少,这为不锈钢支架的生产提供了参考。

高压线束支架多工位连续模设计

该文分析高压线束支架的冲压成形工艺及排样方法,阐述该连续冲裁模的结构及工作零件的加工方法,凹模采用镶拼结构,节约模具钢,零件加工难度降低,制造成本降低。实践证明,该模具结构合理,冲件质量稳定,较好地满足冲件精度和批量生产的要求。

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。

基于改性PP成型的工控机电路板支撑架注射模设计

针对工控机电路板支撑架大型塑件的成型,选用了一种玻纤改性增强聚丙烯(PP)复合材料用于塑件的注射成型。模具结构为三板模结构,分3次开模打开。为保证塑件模腔充填均衡性、饱满性而设计了两个点浇口用于模腔的浇注。针对塑件二级子特征较多,特别是异型螺柱深筋位较多的特点,设计了多个局部镶件用于这些局部特征的成型,在提高局部成型镶件强度的同时,降低了这些成型件的加工难度。针对模腔局部位置排气难点,设置了多个透气镶件以增强排气。设置了锁扣机构、定距拉杆机构用于模具的开模闭模控制;设计了弹料机构用于流道废料的可靠脱模、定位机构以确保塑件的成型精度和模具工作寿命;3个滑块机构用于塑件侧壁直壁及直壁上侧孔的成型与脱模。模具结构形式合理,成型件便于加工且实用可靠,能为同类模具设计提供有益借鉴。

镇国寺大殿尺度规律研究

对以材份制度为代表的中国中古时期木构建筑模数制研究,提出了以足材而不以份为模数单位进行探索的思路。山西平遥镇国寺大殿为《营造法式》颁行前北方七铺作下昂造木构的典型实例,利用精细测绘报告提供的数据,对其作出了基于足材模数单位的尺度规律解释。在数据拟合的同等误差水平上,与现有整数尺模数或份数模数的解释形成竞争性观点。强调栱长指标在尺度研究中的重要性,对现有尺度研究中昂制47份的典型现象作出解释,提出了早期铺作双向栱枋构件的栱长足材假说,详细讨论了斗的方向性、实长与心长、影栱配置与檐椽平长等问题,并解释了镇国寺大殿两组栱长的特异表现,实现了对构件尺度、空间跨度、构造关系、立面视觉的综合研究。附录部分对笔者已发表的佛光寺东大殿尺度规律研究成果作出修订,提出了与镇国寺大殿衔接的规律解释以及新的足材模数取值。

数字鸿沟与居民收入流动性研究

收入流动性是理解居民收入分配不平等的重要视角。本研究以收入排名变化为基础重构收入流动性指标,探究数字鸿沟对居民绝对和相对收入流动性的影响。研究发现,数字鸿沟对居民的绝对收入流动性具有显著负向影响,并会导致居民收入阶层向下流动和不流动,抑制居民收入阶层向上流动。机制分析发现,数字鸿沟会通过抑制创业和削弱信贷可得性来影响居民的收入流动性。异质性分析显示,数字鸿沟对非老年人、中西部地区和农村居民的收入流动性存在显著负向影响。本研究深化了数字鸿沟对居民收入流动性影响的认识,为改善与优化居民收入分配提供了有益参考。

汽车变速器支架冲压成形工艺参数优化

该文以汽车变速器支架为研究对象,利用Dynaform软件研究其冲压成形过程出现的常见缺陷和问题。首先采用单因素分析确定正交试验的参数范围,然后通过正交试验和极差分析,获得各参数对最大减薄率的影响主次顺序,即冲压速度大于摩擦系数大于模具间隙;对于最大增厚率,冲压速度大于模具间隙大于摩擦系数,相对最优工艺参数组合为摩擦系数0.100、模具间隙1.44 mm、冲压速度1000 mm/s。最大减薄率的数值为15.345%、最大增厚率的仿真数值为16.017%,优化后的零件成形质量良好,可降低破裂的风险。

武汉青山长江公路大桥宽幅钢箱梁悬臂拼装横向线形匹配技术

武汉青山长江公路大桥主桥为主跨938 m的双塔双索面全飘浮体系斜拉桥,主跨整体式钢箱梁高4.5 m、全宽48 m,采用500 t架梁吊机分节段悬臂拼装架设。钢箱梁悬臂拼装时,架梁吊机站位节段、待架节段由于荷载及约束不同,横截面变形呈现出不同的趋势,线形匹配难度大。为解决该问题,主跨钢箱梁悬臂拼装时选择上、下游分体式架梁吊机,减少架梁吊机自重;经比选选择横桥向27.7 m间距的架梁吊机站位,减小了架梁吊机荷载对横向线形匹配的影响;通过设置顶压装置(由顶压牛腿、支承底座组成),在架梁吊机站位节段、待架节段钢箱梁边腹板处施加1500 kN顶压力,配合少量马板,一次加载完成对接口竖向变形匹配调整。施工后,钢箱梁横向线形匹配精度均满足要求。

基于Solidworks的育苗容器成型机支架结构优化设计

支架作为育苗容器成型机重要的零部件,其结构好坏直接影响安全生产。以初步设计的支架零件为研究对象,利用Solidworks对其进行静力学分析,得到其承受最大应力为150.7 MN·m^(-2),最小安全系数为2.333。为获得最优化设计,采取静力学有限元分析和设计算例迭代优化的方法自动更改参数值并优化计算。算例共获得7组参数,其中支架厚度4.5 mm、质量5.456 kg为最优设计。优化后的支架减少约16%的材料,此时其承受最大应力为156.0 MN·m^(-2),最小安全系数为2.254,各项数据满足强度要求。

足部自动伸缩支架在下肢肌力障碍患者踝泵运动中的应用

目的探讨足部自动伸缩支架在下肢肌力障碍患者踝泵运动中的应用效果。方法选择2019年6月-2020年6月我院收治的下肢肌力障碍患者80例,按随机数字表法分为对照组和观察组,各40例。对照组行常规踝泵运动,观察组使用自制足部自动伸缩支架干预。比较两组足下垂、下肢症状性深静脉血栓形成(DVT)的发生率、康复锻炼依从性、肌力改变及患侧踝关节活动度。结果观察组足下垂、下肢症状性DVT发生率低于对照组,康复锻练依从性良好率高于对照组(P<0.05);观察组肌力改善率高于对照组(P<0.05);两组干预后踝关节背屈与跖屈角度均高于干预前,且观察组高于对照组(P<0.05)。结论足部自动伸缩支架应用于下肢肌力障碍患者踝泵运动中,可有效提高患者康复锻炼依从性,改善肌力,提高踝关节背屈与跖屈角度,预防足下垂、下肢症状性DVT发生,可应用于临床。

移动式多点出料装置设计与试验

目前,筒仓仓群的进料传统工艺路线是在每个仓顶上布置有一台带式输送机,通过搭接方式由一台传递给另一台,实现物料的连续输送。其在每台带式输送机的出料口处设置有三通,一通流向料仓仓顶的进料点,一通流向下台带式输送机,导致工艺配置复杂、设备布置繁琐,操作起来不方便,故障率也会增高。为此,设计了一种移动式多点出料装置,包括:机架布置在输送机托架上方,托架上固定有滑轨;滚轮、驱动机安装在机架上且二者传动连接;导向托架与机架固定,其上安装有出料辊和托辊组,出料辊与托辊组共同对输送带进行滚动支撑,导向托架的一端固定有出料斗,其出料端布置在输送机托架一侧。上述设置保证了带式输送机出料位置可调,当需要对依次排列的多个料仓进行输送进料时,只需要布置一台带式输送机即可。样机调试运行及对生产试验结果表明:装置设计的各项技术指标均符合国家标准的规定和设计规范要求,能够满足市场需求和生产需要,解决了料仓仓顶多点进料的工艺难点。