根管治疗药物及其材料的细胞毒性研究进展

根管治疗中使用的消毒药物和根充材料对人体的安全性历来受到人们的关注。细胞毒性是评价其安全性的重要指标之一。下面就近年来有关常用根管冲洗剂、根管消毒药物、根管充填材料、根尖倒充填材料和髓腔穿孔修复材料的细胞毒性的研究进展作一综述。     

Vitapex与根管糊剂治疗慢性根尖周炎的效果比较

目的比较Vitapex与根管糊剂治疗慢性根尖周炎的临床效果。方法将360例患者(398颗患牙)随机分成A、B两组,A组(204颗患牙)用Vitapex加牙胶尖行根管充填,B组(194颗患牙)用传统根管糊剂加牙胶尖充填,随访1年后评定其临床疗效。结果A组治愈162颗,好转24颗,总有效率为91.18%。B组治愈116颗,好转22颗,总有效率71.13%,两组比较差异有统计学意义(χ2=26.39,P<0.05)。结论Vitapex在根管治疗中的效果明显优于传统根管糊剂,值得推广应用。     

根管锥度和循环疲劳对牙根力学性能的影响

目的：分析根管预备锥度和循环疲劳对离体牙根力学性能的影响。方法：将32颗离体下颌第一前磨牙随机分成4组,每组8颗牙齿,截冠后将每组的牙根分别预备成0.02、0.04、0.06、0.08锥度,使用侧方加压充填根管。随后每组中随机抽取4颗牙根做循环疲劳实验,疲劳前后均做扫描电镜观察牙根表面形态,最后对所有牙根进行抗压强度测试。结果：各锥度组随锥度的增大牙根抗压强度值有降低趋势,但无统计学差异（P〉0.05）;疲劳实验后0.08锥度牙根表面裂纹明显多于疲劳前,疲劳实验中实验组和对照组两组离体牙根抗压强度值无统计学差异（P〉0.05）;且疲劳和锥度两因素之间没有交互作用（P〉0.05）。结论：根管预备后锥度在0.08以内对牙根的整体抗压性能和抗疲劳性能无明显影响。     

四种粘结材料对纤维桩在不同深度根管内的固位力的影响——薄片推出实验

目的:比较4种不同树脂粘结材料在不同深度根管内粘固纤维桩的推出强度。方法:28个单根管离体前牙截冠后行根管充填和桩道预备,随机分为4组,分别用不同的粘结材料(Ⅰ:XP Bond-Dual Cure Calibra resincement;Ⅱ:XP Bond-Dual Cure Fluorocore2;Ⅲ:Excite DSC MultiCore Flow;Ⅳ:Multilink Primer A/B MultilinkAutomix)粘固纤维桩。粘固了纤维桩的牙根切割为1mm厚的试件并将其按照根管的深度分为上部、中部和下部3组,测试其推出强度。结果:Ⅰ组、Ⅱ组上部的推出强度均显著高于下部(P<0.05),Ⅲ组、Ⅳ组的推出强度在不同深度根管间无显著性差异(P>0.05)。结论:材料的类型和根管的深度对纤维桩的固位有影响。     

两种桩核系统在残冠残根修复中的临床观察

目的比较石英纤维桩与金属铸造桩在残冠残根修复中的临床效果。方法选择残冠、残根患者145例,合计181颗患牙。经完善的根管治疗后,根据患者意愿,分为A组（纤维桩）和B组（铸造金属桩）,此：较二组患者6～24个月临床复诊疗效情况。结果A组1例桩折,1例桩核松动、脱落,1例根尖周炎,成功率96．94％;B组5例根折,1例桩折,2例桩核松动、脱落,1例根尖周炎,2例牙龈晦暗,成功率86．75％,组间差异有统计学意义（P〈0．05）。结论石英纤维桩应用于残根残冠修复的临床效果优于铸造金属桩。     

Research on Hyperparameter Optimization of Concrete Slump Prediction Model Based on Response Surface Method

In this paper, eight variables of cement, blast furnace slag, fly ash, water, superplasticizer, coarse aggregate, fine aggregate and flow are used as network input and slump is used as network output to construct a back-propagation (BP) neural network. On this basis, the learning rate, momentum factor, number of hidden nodes and number of iterations are used as hyperparameters to construct 2-layer and 3-layer neural networks respectively. Finally, the response surface method (RSM) is used to optimize the parameters of the network model obtained previously. The results show that the network model with parameters obtained by the response surface method (RSM) has a better coefficient of determination for the test set than the model before optimization, and the optimized model has higher prediction accuracy. At the same time, the model is used to evaluate the influencing factors of each variable on slump. The results show that flow, water, coarse aggregate and fine aggregate are the four main influencing factors, and the maximum influencing factor of flow is 0.875. This also provides a new idea for quickly and effectively adjusting the parameters of the neural network model to improve the prediction accuracy of concrete slump.     

Current Reviews in Musculoskeletal Medicine: Current Controversies for Treatment of Meniscus Root Tears

Purpose of ReviewThe role of the meniscus in preserving the biomechanical function of the knee joint has been clearly defined. The hypothesis that meniscus root integrity is a prerequisite for meniscus function is supported by the development of progressive knee osteoarthritis (OA) following meniscus root tears (MRTs) treated either non-operatively or with meniscectomy. Consequently, there has been a resurgence of interest in the diagnosis and treatment of MRTs. This review examines the contemporary literature surrounding the natural history, clinical presentation, evaluation, preferred surgical repair technique and outcomes.Recent FindingsSurgeons must have a high index of suspicion in order to diagnose a MRT because of the nonspecific clinical presentation and difficult visualization on imaging. Compared with medial MRTs that commonly occur in middle age/older patients, lateral meniscus root injuries tend to occur in younger males with lower BMIs, less cartilage degeneration, and with concomitant ligament injury. Subchondral insufficiency fractures of the knee have been found to be associated with both MRTs and following arthroscopic procedures. Meniscus root repair has demonstrated good outcomes, and acute injuries with intact cartilage should be repaired. Cartilage degeneration, BMI, and malalignment are important considerations when choosing surgical candidates. Meniscus centralization has emerged as a viable adjunct strategy aimed at correcting meniscus extrusion.SummaryMeniscus root repair results in a decreased rate of OA and arthroplasty and is economically advantageous when compared with nonoperative treatment and partial meniscectomy. The transtibial pull-through technique with the addition of centralization for the medial meniscus is associated with encouraging early results.     

翼管在内镜经鼻颅底手术中的标志作用

目的通过影像学和解剖学方法进行研究以明确翼管在鼻内镜经鼻颅底手术中的价值并为临床提供参考。方法选23具尸头行冠状位及轴位高分辨CT扫描,观察翼管及其与周围结构的关系,并测量相关距离。选其中3具经过动脉灌注的尸头,分别采用经上颌窦、经鼻至翼腭窝-海绵窦入路进行鼻内镜下的解剖学研究。结果高分辨CT能够清晰显示翼管形态、走行及其与周围结构的关系。所有翼管均位于颈内动脉管水平段或其以下层面。鼻内镜解剖与相应的影像学提示相同,翼管内容恒定地指向颈内动脉前膝;翼管和圆孔之间的距离标定了一个手术门户。结论翼管是内镜经鼻颅底手术的一个重要解剖标志,作为骨性管道,高分辨CT可以清晰显示翼管。