羧甲基壳聚糖氯已定合剂抵制粪肠球菌效果体外研究

目的 评价羧甲基壳聚糖氯已定合剂对于粪肠球菌的抑菌效果。方法 2012年10月在辽宁省疾病控制中心微生物实验室采用纸片扩散法药敏实验测定2%氯已定,110、120、140、160、180、200 mg/mL羧甲基壳聚糖氯已定合剂,5.0 mg/mL羧甲基壳聚糖,Apexcal对粪肠球菌形成的抑菌环直径并进行统计学分析。结果 120、140 mg/mL羧甲基壳聚糖氯已定合剂的抑菌环直径差异无统计学意义（P＞0.05）,且明显大于2%氯已定和110、160、180、200 mg/mL羧甲基壳聚糖氯已定合剂,差异有统计学意义（均P＜0.05）。各个浓度的羧甲基壳聚糖氯已定合剂以及2%氯已定的抑菌环直径都大于5.0 mg/mL羧甲基壳聚糖和Apexcal组,差异均有统计学意义（均P＜0.05）。5.0 mg/mL羧甲基壳聚糖直径明显大于Apexcal组,差异有统计学意义（P＜0.05）。结论 120、140 mg/mL羧甲基壳聚糖氯已定合剂是再治疗根管的有效消毒药物。     

醋酸氯己定和次氯酸钠对粪肠球菌抑菌作用的体外研究

目的：体外药敏试验评价醋酸氯己定（CHA）和次氯酸钠（NaCIO）对粪肠球菌的抑菌效果。方法：采用纸片扩散法药敏试验观察不同浓度醋酸氯已定和次氯酸钠对粪肠球菌的抑菌环直径（mm）,方差分析评价药物对粪肠球菌的抑菌效果。结果：2％的CHA抑菌环最大;1％CHA、0．5％CHA和5．25％NaCl0的抑菌环直径无显著性差异,均大于2．5％NaCl0;NaCl0抑菌环直径随浓度的增大而增大。0．5％NaCl0抑菌环与对照组无显著性差异。结论：低浓度CHA即可达到高浓度NaCl0的抑菌效果,高浓度NaCl0的抑菌效果优于低浓度NaCl0。     

根管内粪肠球菌感染的研究进展

粪肠球菌（E.faecalis）在治疗失败根管内的检出率较高,是根管持续感染和再感染的重要微生物之一。粪肠球菌在治疗前后根管内的感染特点不同,并且对抗菌药物有较强耐药性。目前的根管清理和消毒方法难以将定植于根管中的粪肠球菌彻底清除。本文就有关根管内粪肠球菌的感染特点及其对抗菌剂的敏感性研究进展作一综述。     

不同类型激光对根管内粪肠球菌消毒作用的研究进展

近年来,越来越多的新技术被用于牙科治疗中,其中激光的应用更是获得广泛关注。在根管消毒方面,已有许多研究证实,不同类型激光器在运用于根管消毒时,对粪肠球菌均有一定杀菌作用,可考虑作为辅助技术协助完成根管治疗。现今,常应用于根管消毒的激光器包括Nd：YAG、Er：YAG、Er,Cr：YSGG激光及KTP激光和半导体激光等,这些激光器的工作原理相互之间都略有不同,其作用效果也存在一定差异。本文就不同类型激光对根管内粪肠球菌消毒作用的研究进展作一综述。     

再感染根管内粪肠球菌生物膜的研究进展

粪肠球菌是顽固性和继发性根管感染中最易分离到的细菌,其主要致病机制之一是形成生物膜.笔者下面就再感染根管内粪肠球菌的分离与鉴定、影响粪肠球菌生物膜形成的相关因素等作一综述.     

次氯酸钠对根管内粪肠球菌杀菌效果的体外实验

目的评价次氯酸钠对根管内粪肠球菌的杀菌效果。方法将45个离体前磨牙的感染根管标本分为6组，1、2组用5．25％及2．5％次氯酸钠冲洗，3组用0．9％NaCl冲洗，4、5组在根管预备时辅以5．25％及2．5％次氯酸钠冲洗，6组在根管预备时辅以0．9％Nacl冲洗。冲洗前、冲洗后即刻及冲洗后72h分别取样培养。结果6组根管内的细菌量均显著下降。1、2组差异无统计学意义（P〉0．05），但均好于3组（P〈0．05）。4、5和6组差异均有统计学意义（P〈0．05）。根管冲洗后培养72h均有细菌生长。结论2．5％次氯酸钠基本可达到更高浓度的灭菌效果，但是经过机械预备和次氯酸钠化学消毒后的根管内仍有细菌残留。     

纳米银颗粒联合氢氧化钙对饥饿期粪肠球菌生物膜的作用

目的:将氢氧化钙和纳米银联合,探讨其对饥饿期粪肠球菌生物膜的抑制效果.方法:使用256个牙根样本建立饥饿期粪肠球菌生物膜体外模型,使用平板菌落计数法和结晶紫染色法测定不同药物[Ca(OH)2+AgNP,Ca(OH)2,AgNPy不同作用时间(1、7d)对饥饿期粪肠球菌生物膜的抑制效果.以灭菌水作为实验对照组.采用SPSS13.0软件包对数据进行统计学分析.结果:在1d和7d时,Ca (OH)2+AgNP对粪肠球菌生物膜的抑制效果强于Ca (OH)2和AgNP;同时,AgNP对粪肠球菌生物膜的抑制效果显著强于Ca(OH)2.Ca(OH)2在7d时对粪肠球菌生物膜的抑制效果强于1d时;Ca(OH)2+AgNP和AgNP在7d和1d时对粪肠球菌生物膜的抑制效果无显著差异.结论:纳米银颗粒联合氢氧化钙对饥饿期粪肠球菌生物膜具显著的抑制作用.     

EDTA与次氯酸钠联合应用对根管内粪肠球菌清除效果:体外研究

目的:评价17%EDTA联合1%次氯酸钠对根管内粪肠球菌的清除效果.方法: 将40 个离体前牙的感染根管标本随机分为5组,器械预备时分别辅以冲洗液冲洗根管.其中A、B、C组分别用5.25%、2.5%及1%次氯酸钠冲洗,D组用17%EDTA联合1%次氯酸钠冲洗,E组用0.9%NaCl冲洗.冲洗前、后计数根管内的细菌量,并观察72 h细菌复苏情况.结果: 5 组根管内的细菌量均显著下降(P<0.01),其中D组与A、C组间差异有显著性(P<0.05),与B组间差异无显著性(P>0.05).结论: 17%EDTA联合1%次氯酸钠可有效清除根管内粪肠球菌, 其效果优于1%次氯酸钠,与2.5%次氯酸钠相近似.     

Nd：YAP激光配合不同冲洗液对根管粪肠球菌消除作用的体外研究

目的 通过观察Nd：YAP激光分别与3% H₂O₂、3% NaClO溶液和2% CHX溶液3种临床常用的根管冲洗剂联合使用时,对根管内粪肠球菌的杀灭效果,为临床寻找更有效、更理想的根管消毒方法提供参考。方法 选取48颗成人单根管离体前磨牙,建立粪肠球菌感染根管模型,随机将其均分为6组并做不同处理。A组为生理盐水冲洗组,B组为3% NaClO溶液冲洗组（阳性对照组）,C组为Nd：YAP激光+3% NaClO溶液处理组,D组为Nd：YAP激光+2% CHX溶液处理组,E组为Nd：YAP激光+3% H₂O₂溶液处理组,F组为Nd：YAP激光+NS处理组。激光使用参数均为5 Hz,280 mJ,5 s。选用纸尖法取样,稀释培养48 h后,计算每个样本菌落形成单位（CFU）值。使用SAS 8.02统计软件对结果进行统计学分析。结果 B、C、D、E、F组的CFU值均显著低于A组（P<0.05）,表明该5组的杀菌效果优于A组,其中C、D组的杀菌效果最为显著。阳性对照组（B组）结果显著低于E、F组（P<0.05）,表明B组杀菌效果优于E、F组。而E、F组的CFU值之间的差异则无统计学意义（P>0.05）。结论 Nd：YAP激光在5 Hz,280 mJ的参数设定下对粪肠球菌具有显著的清除作用,明显优于单纯使用生理盐水冲洗;Nd：YAP/NaClO组和Nd：YAP/CHX组对粪肠球菌生物膜具有最为有效的清除作用。     

氯化镧对根管内粪肠球菌抗菌效果的体外实验

目的:研究氯化镧、FC、CP、氢氧化钙丙二醇糊剂4种根管消毒剂对离体牙根管内粪肠球菌的抗菌性能。方法:选取72个新鲜拔除的单根管前磨牙,随机分为4个实验组(氯化镧组、FC组、CP组、氢氧化钙丙二醇糊剂组)、1个阴性对照组和1个阳性对照组,每组12个牙。所有牙清理根管后灭菌,除阴性对照组不感染细菌外,其余各组均建立粪肠球菌感染根管模型。建模后,4个实验组分别在根管内放置氯化镧药液、FC、CP、氢氧化钙丙二醇糊剂;阴性和阳性对照组放置生理盐水,37℃、50 mL/L CO2培养箱内培养。分别于培养后3 d和7 d时,取各组根管内壁牙本质粉末用BHI培养基继续培养72 h,比浊仪检测各样本的浊度。结果:①药物处理第3天时,氯化镧组牙本质小管中残留菌量较阳性对照组少,但高于阴性对照组和FC组、氢氧化钙丙二醇糊剂组(P<0.05),与CP组无显著性差异(P>0.05);②药物处理第7天时,FC组、CP组、氢氧化钙丙二醇糊剂组和氯化镧组4种消毒剂牙本质小管内残留细菌量较阳性对照组有明显减少(P<0.05),与阴性对照组相比,差异均无统计学意义(P>0.05)。结论:根管内放置氯化镧药液7 d可有效抑制粪肠球菌生长。     

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目的评价自制洗必泰凝胶对粪肠球菌的抑菌效果。方法于2011年9月至2012年3月在辽宁省疾病控制中心微生物实验室采用纸片扩散法药敏实验测定生理盐水（A组）、Vitepex（B组）、2％洗必泰溶液（c组）和洗必泰凝胶（D组）对粪肠球菌形成的抑菌环直径并进行统计学分析。结果C组和D组的抑菌环直径明显大于B组,差异有统计学意义（p〈0．01）;C组和D组抑菌环直径的差异无统计学意义（P〉0．05）;4组组内各时间点抑菌环直径差异均无统计学意义（P〉0．05）。结论洗必泰凝胶是根管再治疗的理想消毒药物。     

Survival of Enterococcus faecalis in infected dentinal tubules after root canal filling with different root canal sealers in vitro

AIM: To investigate the ability of different endodontic sealers and calcium hydroxide to kill bacteria in experimentally infected dentinal tubules. METHODOLOGY: Fifty-six human root segments were enlarged to size 2 (ISO size 090) Largo Peeso Reamer. After treatment with 17% EDTA and 5% NaOCl for 4 min each, the specimens were infected with Enterococcus faecalis for 3 weeks. The roots were divided into eight groups and filled with gutta-percha and AH Plus (AH); Grossman's sealer (GS); Ketac-Endo (KE); Apexit (AP); RoekoSeal Automix (RSA); or RoekoSeal Automix with an experimental primer (RP), or calcium hydroxide (CH) only. One group of specimens was left unfilled for control (CT). Following storage in humid conditions at 37 degrees C for 7 days, the root canals were re-established with new sterile Largo size 2. Dentine samples from each canal were then collected using a sterile size 5 (ISO size 150) Largo Peeso Reamer. The number of colony-forming units (CFU) was determined for each sample. RESULTS: The mean log10 CFU in all test groups was significantly lower (P < 0.05) than that in the CT group. Root filling with AH and GS killed bacteria (mean CFU = 0) in the dentinal tubules. The mean log10 CFU for the CH group (0.53) was lower than that of RSA, AP, RP and KE (1.36, 1.40, 1.46 and 1.94, respectively), but only the difference between the CH and the KE groups was statistically significant (P < 0.05). CONCLUSION: Root fillings in vitro with gutta-percha and AH or GS were effective in killing E. faecalis in dentinal tubules. Other endodontic sealers, as well as CH, were less effective.     

In vitro evaluation of the action of irrigating solutions associated with intracanal medications on Escherichia coli and its endotoxin in root canals

Objective

The purpose of this study was to evaluate the efficacy of auxiliary chemical substances and intracanal medications on Escherichia coli and its endotoxin in root canals.

Material and Methods

Teeth were contaminated with a suspension of E. coli for 14 days and divided into 3 groups according to the auxiliary chemical substance used: G1) 2.5% sodium hypochlorite (NaOCl); G2) 2% chlorhexidine gel (CLX); G3) pyrogen-free solution. After, these groups were subdivided according to the intracanal medication (ICM): A) Calcium hydroxide paste (Calen®), B) polymyxin B, and C) Calcium hydroxide paste+2% CLX gel. For the control group (G4), pyrogen-free saline solution was used without application of intracanal medication. Samples of the root canal content were collected immediately after biomechanical preparation (BMP), at 7 days after BMP, after 14 days of intracanal medication activity, and 7 days after removal of intracanal medication. The following aspects were evaluated for all collections: a) antimicrobial activity; b) quantification of endotoxin by the Limulus Amebocyte Lysate test (LAL). Results were analyzed by the Kruskal-Wallis and Dunn’s tests at 5% significance level.

Results

The 2.5% NaOCl and CLX were able to eliminate E. coli from root canal lumen and reduced the amount of endotoxin compared to saline.

Conclusions

It was concluded that 2.5% NaOCl and CLX were effective in eliminating E. coli. Only the studied intracanal medications were to reduce the amount of endotoxin present in the root canals, regardless of the irrigant used.     

In vitro evaluation of the antimicrobial effects of a root canal sealer-antibiotic combination against Enterococcus faecalis

The purpose of this in vitro study was to evaluate the antimicrobial effects of five antibiotics when added to Kerr Pulp Canal Sealer EWT against Enterococcus faecalis. Five antibiotics: amoxicillin, penicillin, clindamycin, metronidazole, and doxycycline, were added separately to Kerr sealer. Thirty brain heart infusion agar plates were inoculated with E. faecalis and sterile paper discs containing a sealer-antibiotic combination were randomly assigned to the inoculated plates. Kerr sealer on a sterile paper disc and a blank sterile paper disc served as the controls. Fifteen plates were incubated aerobically and the remaining 15 plates were incubated anaerobically at 37 degrees C. The zones of inhibition were measured at 48 hours. No significant differences (p > 0.05) were found between aerobic and anaerobic groups. The groups were combined and data analysis using a one-way ANOVA and Tukey's post hoc test was performed. Results revealed that sealer-antibiotic combinations containing amoxicillin, penicillin, clindamycin, and doxycycline had a significant difference (p < 0.001) in the mean zones of inhibition when compared to Kerr EWT sealer alone. No significant differences (p > 0.05) were found between the metronidazole-sealer combinations and Kerr EWT sealer alone.     

羧甲基壳聚糖对兔颞下颌关节软骨修复的作用

目的：比较羧甲基壳聚糖与透明质酸钠对兔颞下颌关节软骨损伤后修复的作用。方法：27只新西兰白兔，随机分成4组：A组10只、B组10只、C组5只、D组2只。A、B、C组于下颌髁突功能面制造直径2mm、深2．0-2．5mm的骨、软骨缺损，局部分别应用羧甲基壳聚糖、透明质酸钠、生理盐水2．0ml处理，D组为健康对照组。术后1、2、4、8、12周处死实验动物，D组动物和手术组于术后1周和12周同时处死。取髁突标本进行大体形态和组织学观察。结果：B、C组软骨损伤区形成骨纤维组织修复，术后12周，C组出现明显的软骨退行性变，B组无明显退变：A组软骨缺损区形成软骨样组织修复，且与邻近正常软骨层相连续，未见明显的软骨退变。结论：羧甲基壳聚糖有明显促进关节软骨再生修复和减轻关节软骨退变的作用；透明质酸钠无明显促进关节软骨再生修复的作用，但具有减轻关节软骨退变的作用。     

Antibacterial effect of calcium hydroxide combined with chlorhexidine on Enterococcus faecalis: a systematic review and meta-analysis

Objective

Enterococcus faecalis (E. faecalis) is the most frequently isolated strain in failed endodontic therapy cases since it is resistant to calcium hydroxide (CH). Whether a combination of CH and chlorhexidine (CHX) is more effective than CH alone against E. faecalis is a matter of controversy. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the literature.

Material and Methods

A comprehensive search in PubMed, EMbase, EBSCOhost, The Cochrane Library, SciELO, and BBO databases, Clinical trials registers, Open Grey, and conference proceedings from the earliest available date to February 1, 2013 was carried out and the relevant articles were identified by two independent reviewers. Backward and forward search was performed and then inclusion and exclusion criteria were applied. The included studies were divided into "comparisons" according to the depth of sampling and dressing period of each medicament. Meta-analysis was performed using Stata software 10.0. The level of significance was set at 0.05.

Results

Eighty-five studies were retrieved from databases and backward/forward searches. Fortyfive studies were considered as relevant (5 in vivo, 18 in vitro, 18 ex vivo, and 4 review articles). Nine studies were included for meta-analysis. Inter-observer agreement (Cohen kappa) was 0.93. The included studies were divided into 21 comparisons for meta-analysis. Chi-square test showed the comparisons were heterogeneous (p<0.001). Random effect model demonstrated no significant difference between CH/CHX mixture and CH alone in their effect on E. faecalis (p=0.115).

Conclusions

According to the evidence available now, mixing CH with CHX does not significantly increase the antimicrobial activity of CH against E. faecalis. It appears that mixing CH with CHX does not improve its ex vivo antibacterial property as an intracanal medicament against E. faecalis. Further in vivo studies are necessary to confirm and correlate the findings of this study with the clinical outcomes.     

Comparative evaluation of propolis and triantibiotic mixture as an intracanal medicament against Enterococcus faecalis

Introduction

The aim of this study was to evaluate and compare the antimicrobial activity of calcium hydroxide, triantibiotic mixture (TAM), and an ethanol extract of propolis as intracanal medicaments on Enterococcus faecalis-infected root canals.

Methods

One hundred twenty extracted intact human permanent incisors were decoronated, and chemomechanical preparation of the root canal was performed. After sterilization of the samples, they were inoculated with pure culture of E. faecalis and incubated. After incubation, colony-forming units were recorded before medication. Then, samples were divided randomly into five groups (n = 24). Each group was then exposed to various intracanal medicaments, namely calcium hydroxide (group 1), TAM (group 2), propolis (group 3), ethanol (group 4), and saline as the control group (group V). The antibacterial effectiveness of the different intracanal medicament was recorded by determining the percentage reduction in colony counts (%RCC) at the end of days 1, 2, and 7. The data were statistically analyzed using one-way analysis of variance and Tukey Honestly Significant Difference (HSD) post hoc test.

Results

The %RCC was highest for propolis showing 100% reduction on day 2 followed by TAM showing 82.5%, 92.2%, and 98.4% of reduction on days 1, 2, and 3, respectively. Calcium hydroxide showed a gradual increase in antibacterial activity with a maximum of 59.4% on day 7.

Conclusions

Propolis was more effective than TAM against E. faecalis at a 2-day time period, and both were equally effective at 7 days.     

Effectiveness of 2% chlorhexidine gel and calcium hydroxide against Enterococcus faecalis in bovine root dentine in vitro

AIM: To evaluate the effectiveness of 2% chlorhexidine gluconate gel and calcium hydroxide (Ca(OH)2) as intracanal medicaments against Enterococcus faecalis. METHODOLOGY: One hundred and eighty dentine tubes prepared from intact freshly extracted bovine maxillary central incisors were infected in vitro for 7 days with E. faecalis. The specimens were divided into four groups, according to the intracanal medicament used, as follows: Group 1: 2% chlorhexidine gluconate gel; Group 2: calcium hydroxide in a viscous vehicle (polyethyleneglycol 400); Group 3: 2% chlorhexidine gluconate gel + calcium hydroxide and Group 4: Brain Heart Infusion (BHI) broth (control group). The medicaments were placed into the canal lumen and left there for experimental times of 1, 2, 7, 15 and 30 days. After each period, irrigation with sterile saline to remove the medicament was performed and the canals were dried with sterile paper points. Dentine chips were removed from the canals with sequential sterile round burs at low speed. The samples obtained with each bur were immediately collected in separate test tubes containing BHI broth. The tubes were incubated at 37 degrees C and daily observed for microbial growth, visualized by the medium turbidity. RESULTS: Chlorhexidine gel alone completely inhibited the growth of E. faecalis after 1, 2, 7 and 15 days. Calcium hydroxide allowed microbial growth at all experimental times. The combination of chlorhexidine and Ca(OH)2 was effective after 1 and 2 days demonstrating 100% antibacterial action; however, its antibacterial activity reduced between 7 and 15 days. CONCLUSION: Under the conditions of this study, it can be concluded that 2% chlorhexidine gel alone was more effective against E. faecalis than calcium hydroxide (P < 0.05). However, its antibacterial activity depended on how long it remained inside the root canal.