CLEANING ABILITY OF CHLORHEXIDINE GEL AND SODIUM HYPOCHLORITE ASSOCIATED OR NOT WITH EDTA AS ROOT CANAL IRRIGANTS: A SCANNING ELECTRON MICROSCOPY STUDY

The aim of this study was to evaluate the cleaning efficacy of 2% chlorhexidine gluconate gel (CHX) compared to 2.5% sodium hypochlorite solution (NaOCl) associated or not with 17% EDTA used as irrigants during the biomechanical preparation. Fifty freshly extracted single-rooted human teeth with complete apex formation were randomly divided into five groups: G1 - sterile saline, G2 - 2.5% NaOCl, G3 - 2% CHX, G4 - 2.5% NaOCl + EDTA and G5 - 2% CHX + EDTA. The specimens of G1 were subdivided into two control groups. The teeth were decoronated and the coronal and middle root thirds were prepared with Gates-Glidden burs, and the apical third was reserved to manual instrumentation. All procedures were performed by a single operator. In all groups, 2 mL of irrigant was delivered between each file change. The teeth were sectioned and prepared for analyses under scanning electron microscopy (SEM). SEM micrographs were graded according to a score scale by two examiners. Data were analyzed statistically by Kruskal-Wallis and Dunn tests at 1% significance level. The best results were obtained in the groups in which the irrigant was used followed by the chelating agent. No statistically significant difference was observed among G4, G5 and the positive control group (p<0.01). The groups G2 and G3 were significantly different from the others, presenting the worst cleaning capacity. In conclusion, the use of the chelating agent is necessary to obtain clean canal walls, with open tubules and no heavy debris. The use of 2% chlorhexidine gluconate gel alone is not able to remove the smear layer.     

Non-surgical root canal treatment of Dens invaginatus: reports of three cases

Dens invaginatus is a rare developmental malformation of teeth showing a deep infolding of enamel and dentine which may extend deep into the root. To date, conventional root canal therapy, endodontic surgery and extraction have been reported as treatment modalities, when the pulpo-dentinal complex of such teeth is affected. In the present report, non-surgical endodontic treatment of three maxillary lateral incisors with invaginatus (DI) is discussed. The Tri Auto ZX rotary system was used for shaping the root canals of two affected teeth and the Profile system was used in the third. Teeth with periradicular lesions received calcium hydroxide as an interim therapy. Two teeth were obturated with gutta percha points and AH Plus sealer using cold lateral compaction. In the third case, obturation was accomplished using a coated carrier system (Thermafil) due to the specific shape of the root canal system. Twelve months postoperatively all teeth were asymptomatic with resolution of the periapical radiolucency on two affected teeth, as confirmed radiographically. Healing was achieved without any need for further surgical intervention.     

Influence of preparation design and spacing parameters on the risk of chipping of crowns made with Cerec Bluecam before cementation

Purpose

To evaluate the influence of the preparation design and spacing parameters on the risk of chipping of crowns made by CEREC Bluecam before cementation.

Increased apical enlargement contributes to excessive dentin removal in curved root canals: a stepwise microcomputed tomography study

Introduction

To determine whether increased apical enlargement would result in a complete preparation of curved canals and to progressively assess shaping quality using multiple microcomputed tomography (MCT) scans.

Methods

Ninety root canals with a curvature of 25° to 50° were selected. Five MCT scans, 1 preoperative and 4 postoperative, were acquired from each canal. Canal preparation was performed up to size 50 using 3 techniques, nickel-titanium (NiTi) hand files, Mtwo (VDW, Munich, Germany), and ProTaper (Maillefer, Ballaigue, Switzerland), by experienced operators in a dental mannequin so as to simulate the clinical conditions. At a level of 1 mm short of the working length, 2 parameters were evaluated in each of the 4 postoperative acquisitions: the percentage of the prepared outline and the amount of dentin removed (the prepared area).

Results

Statistically, there was no significant difference between the 3 systems used regarding the prepared outline. The maximum prepared outline was achieved by the use of NiTi hand files (63%; confidence interval [CI], 54%–73%), whereas Mtwo and ProTaper amounted to 58% (CI, 50%–66%) and 60% (CI, 51%–70%), respectively. In contrast, the dentin area removed by ProTaper was significantly higher than that of Mtwo and NiTi hand files.

Conclusions

Increased apical enlargement of curved canals did not result in a complete apical preparation, whereas it did lead to the unnecessary removal of dentin.     

盐酸伊伐布雷定单层渗透泵控释片的制备与体外释药行为

制备日服1次的盐酸伊伐布雷定（IVB）单层渗透泵控释片。建立了释放度测定方法,单因素考察助悬剂、促渗剂和老化条件等对释药曲线的影响。以片芯中聚氧乙烯（PEO）的用量、控释衣膜中聚乙二醇（PEG）的比例和包衣增重进行3因素3水平的正交设计。最终处方为IVB 16.25 mg,PEO N80 60 mg,羟丙甲基纤维E5 10 mg,乳糖111.75 mg,硬脂酸镁2 mg;包衣液中PEG 15%,醋酸纤维素85%,包衣增重7.5%。体外释药行为表明,药物释放不受环境pH影响,无剂量倾泻风险,释药动力为膜内外渗透压差。IVB渗透泵片能够降低给药次数,提高患者的顺应性,具有临床应用价值。     

Protaper手用镍钛根管锉预备根管的效果分析

目的 评价Protaper手用镍钛根管锉预备磨牙根管的临床疗效.方法 选患牙髓炎和根尖周炎的恒磨牙252颗,用Protaper手用镍钛根管锉预备根管,侧压法根管充填.记录根管预备时间及器械折断数量.根据治疗前、中、后X线片评价根管预备和充填的效果.结果 Protaper手用镍钛根管锉预备磨牙根管时间短,平均单根管预备时间3.55min,效果好,锥度、流畅度好,术后疼痛少、程度轻,减小根管弯曲度,降低根管预备难度.器械折断9支.结论Protaper手用镍钛根管锉预备根管成形、根充效果好,降低预备时间,提高效率,可明显减小根管弯曲度,降低根管预备难度,但大号完成锉的使用需谨慎.在取根管内充填材料方面有独特的优点.     

中药调节兔膝骨关节软骨代谢作用的研究

目的研究中药对软骨细胞活性及代谢反应的调节规律,探讨中药治疗骨关节炎的作用机理。方法从细胞增殖(MTT法)、细胞DNA合成(3H-TdR掺入率)、蛋白多糖的形成(甲苯胺蓝染色)和Ⅱ型胶原的合成(3H-脯氨酸掺入)观察兔膝骨关节软骨细胞代谢变化。结果鹿茸多肽及维骨力对细胞增殖及蛋白多糖合成有促进作用,益气通络方对细胞增殖及蛋白多糖合成起抑制作用。益气通络组、鹿茸多肽组及维骨力组对软骨细胞的增殖有促进作用,与对照组相比有显著性差异(P<0.05);鹿茸多肽组及维骨力组对软骨细胞DNA及Ⅱ型胶原的合成有促进作用,与对照组相比有显著性差异(P<0.05);益气通络组对软骨细胞代谢起抑制作用(P<0.05)。结论益气通络方阻断分解代谢细胞因子,防止胶原纤维转型而促进细胞增殖;鹿茸多肽促进软骨细胞合成代谢而促进软骨细胞增殖,维骨力保护软骨细胞而促进软骨细胞增殖。     

基于一测多评法鉴别蓝芩制剂中的黄柏与关黄柏

目的 建立蓝芩制剂中盐酸黄柏碱、盐酸巴马汀及盐酸小檗碱的HPLC一测多评法,并基于含量测定结果建立蓝芩制剂中黄柏与关黄柏的鉴别方法。方法 采用Agilent 1260色谱仪,Waters Atlantis T3(250 mm×4.6 mm,5μm)色谱柱,以乙腈-0.2%磷酸溶液(每100 mL加十二烷基磺酸钠0.2 g)梯度洗脱,流速为1 mL·min^–1,检测波长为280 nm,柱温30℃,以盐酸小檗碱为参照物,计算盐酸黄柏碱及盐酸巴马汀的相对校正因子,所得结果与外标法结果进行比较,判断该方法的可靠性。利用聚类分析含量测定结果,讨论黄柏与关黄柏对3种生物碱含量的影响,建立鉴别方法,对不同厂家的蓝芩制剂进行测定。结果 盐酸黄柏碱、盐酸巴马汀及盐酸小檗碱分别在1.087～54.35μg·mL^–1,0.100 9～20.18μg·mL^–1,0.536 5～26.82μg·mL^–1内线性关系良好;平均加样回收率分别为91.57%(RSD=3.0%),97.96%(RSD=2.1%),100.6%(RSD...     

Modifying current thin-film microextraction (TFME) solutions for analyzing prohibited substances: Evaluating new coatings using liquid chromatography

For identifying and quantifying prohibited substances, solid-phase microextraction (SPME) continues to arouse interest as a sample preparation method. However, the practical implementation of this method in routine laboratory testing is currently hindered by the limited number of coatings compatible with the ubiquitous high-performance liquid chromatography (HPLC) systems. Only octadecyl (C₁₈) and polydimethylsiloxane/divinylbenzene ligands are currently marketed for this purpose. To address this situation, the present study evaluated 12 HPLC-compatible coatings, including several chemistries not currently used in this application. The stationary phases of SPME devices in the geometry of thin film-coated blades were prepared by applying silica particles bonded with various functional ligands (C₁₈, octyl, phenyl-hexyl, 3-cyanopropyl, benzenesulfonic acid, and selected combinations of these), as well as unbonded silica, to a metal support. Most of these chemistries have not been previously used as microextraction coatings. The 48 most commonly misused substances were selected to assess the extraction efficacy of each coating, and eight desorption solvent compositions were used to optimize the desorption conditions. All samples were analyzed using an HPLC system coupled with triple quadrupole tandem mass spectrometry. This evaluation enables selection of the best-performing coatings for quantifying prohibited substances and investigates the relationship between extraction efficacy and the physicochemical characteristics of the analytes. Ultimately, using the most suitable coatings is essential for trace-level analysis of chemically diverse prohibited substances.     

微波消融治疗胆肠吻合术后肝脏恶性肿瘤术前肠道准备及应用抗生素对降低术后并发症的效果

目的 观察超声引导下微波消融(MWA)治疗胆肠吻合术(BEA)后肝脏恶性肿瘤术前肠道准备及应用抗生素对降低术后并发症及其严重程度的价值。方法 回顾性分析31例接受超声引导下MWA的BEA后肝脏恶性肿瘤患者,其中17例MWA前接受(A组)、14例(B组)未接受肠道准备及应用抗生素,对比观察2组术后并发症发生率及严重程度。结果 2组患者基线特征及原发肿瘤类型差异均无统计学意义(P均＞0.05)。31例均顺利完成MWA。MWA后A组住院时间、发热率、发热持续时间、菌血症发生率及肝脓肿发生率均低于B组(P均＜0.05)。结论 MWA治疗BEA后肝脏恶性肿瘤患者术前肠道准备及合理应用抗生素可明显降低术后并发症发生率及严重程度。