自制根管润滑剂与不同浓度次氯酸钠液组合对粪肠球菌感染根管壁的清洁效果

目的:观察自制根管润滑剂与不同浓度次氯酸钠液组合对体外建立的粪肠球菌感染根管模型的清洁效果.方法:80个新鲜拔除的单根管牙随机分为8组,逐步深入法预备根管,预备过程中各组样本分别使用自制根管润滑剂配合不同浓度次氯酸钠液(5 g/L、25 g/L、52.5吕/L)3组、Glyde凝胶配合不同浓度的次氯酸钠液3组(为阳性对照)、过氧化氢液加生理盐水、蒸馏水(均为阴性对照)润滑、冲洗根管.通过扫描电镜观察根管壁玷污层、碎屑及细菌去除情况,并将样本根中1/3分为10个区采用单盲法分别评分,结果进行统计学分析.结果:除过氧化氢液配合生理盐水组,单纯蒸馏水组外,各润滑剂与次氯酸钠液配合组均能完全去除根中根管壁表面的粪肠球菌,两种润滑剂配合不同浓度次氯酸钠液与过氧化氰液+生理盐水组和单纯蒸馏水组相比,均能有效地去除碎屑和玷污层(P<0.05);两组润滑剂在去除玷污层方面组间相差不显著(P>0.05),次氯酸钠液各浓度之间亦无显著性差异,但对碎屑的去除效果则随次氯酸钠浓度升高效果越好,不同浓度间相差显著(P<0.05).结论:本实验室研制的根管润滑剂与52.5 g/L次氯酸钠液组合能有效去除根中根管壁玷污层和细菌.     

超声下不同根管冲洗剂组合对感染根管内粪肠球菌杀灭效果的研究

目的:比较超声作用下不同根管冲洗剂组合对根管内粪肠球菌的杀灭效果。方法:取粪肠球菌感染根管模型样本90个,随机分为6组(n=15),其中5个样本用于基线对照,10个样本分别按相应分组处理,A组:25 g/L次氯酸钠液液+20 g/L洗必泰液;B组:25 g/L次氯酸钠液+30 m L/L过氧化氢液;C组:10 g/L次氯酸钠液+20 g/L洗必泰液;D组:10 g/L次氯酸钠液+30 m L/L过氧化氢液;E组:52.5 g/L次氯酸钠液阳性对照;F组:生理盐水阴性对照。处理前后从样本的根管壁表面采样,并钻取不同深度牙本质进行细菌培养和计数。结果:A、B、C、D、E组根管壁表面及不同深度牙本质的细菌清除率均显著高于F组(P<0.05);对各层牙本质的细菌清除率,A组高于B、C、D组(P<0.05),与E组相比,除200~300μm深度处明显降低(P<0.05)外,其他各层与E组相当(P>0.05);C组对不同深度牙本质层的细菌清除率均在90%以上,低于A、E组,高于其他各组(P<0.05);B、D组在各不同深度牙本质层的细菌清除率基本相当(P>0.05),低于其他各实验组和E组(P<0.05)。结论:超声辅助下用25 g/L次氯酸钠液联合20 g/L洗必泰液冲洗根管,能有效杀灭根管内的粪肠球菌。     

三种无机纳米抗菌剂对粪肠球菌的抗菌作用

目的:研究纳米银、载银纳米二氧化钛、掺氮纳米二氧化钛对粪肠球菌的抗菌作用。方法:将粪肠球菌在MBECTMP&G Assay中培养24 h,构建粪肠球菌感染模型,扫描电镜观察MBECTMP&G Assay上粪肠球菌感染情况。应用MBECTMP&G Assay以连续稀释法检测纳米银、载银纳米二氧化钛、掺氮纳米二氧化钛的最小抑菌浓度(MIC)和最小生物膜清除浓度(MBEC)。结果:扫描电镜下见粪肠球菌在MBECTM P&G Assay上形成生物膜。纳米银对粪肠球菌的MIC和MBEC分别为62.5 mg/L和1 000 mg/L,载银纳米二氧化钛MIC为64 g/L,但在所用浓度范围内均不能清除生物膜细菌,即未测得MBEC;掺氮纳米二氧化钛的MIC、MBEC均未测得;次氯酸钠的MIC和MBEC分别为6.56 g/L和13.13 g/L。结论:纳米银对粪肠球菌有较强抗菌作用,能清除粪肠球菌生物膜;粪肠球菌对载银纳米二氧化钛和掺氮纳米二氧化钛有较强抵抗力。     

电解质水对粪肠球菌生物膜的杀菌作用研究

目的:观察强酸性电解质水(SAEW)和碱性电解质水(AEW)对粪肠球菌生物膜的杀菌作用。方法:利用BioFluxTM200微流体系统建立粪肠球菌生物膜模型,并分别用SAEW、AEW、52.5 g/L次氯酸钠液(阳性对照)和生理盐水(阴性对照)处理1、5、10 min后,激光共聚焦显微镜(CLSM)观察并采集荧光图像;ImageJ图像分析软件分析并计算各处理组不同时间点的活菌比例。结果:SAEW、AEW和52.5 g/L次氯酸钠液处理1、5、10 min各时间点的活菌比例都显著低于生理盐水组(P<0.05),其中AEW组活菌比例下降幅度最小,与SAEW和52.5 g/L次氯酸钠液处理组相比,各时间点均有统计学差异(P<0.05);而SAEW与52.5 g/L次氯酸钠液处理组相比,各时间点的活菌比例均无统计学差异(P>0.05)。结论:SAEW和AEW对粪肠球菌均有杀菌作用,其中SAEW的作用与52.5 g/L次氯酸钠液相当;而AEW的杀菌效果较弱,且需要延长作用时间。     

粪肠球菌与复发性根尖周炎的相关性及其机制

粪肠球菌可在恶劣的环境中持续生长和繁殖,而在生物膜中具有的极强的生存和致病能力,使其成为根尖周炎复发的重要的致病因素。粪肠球菌的毒力因子,可引起健康组织损伤,增强细菌的黏附能力。粪肠球菌的检出率,在原发性感染根管内为7.5%,但在治疗失败的感染根管中可达到70%以上,即粪肠球菌在原发性根尖周炎患牙的根管内并非主要致病菌。粪肠球菌在根管冠1/3段的感染较重,在根中1/3和根尖1/3段的感染较轻。粪肠球菌对常规的根管消毒和抗菌药物有极强的耐药性,很难用传统的方法将其于根管内彻底清除,因此研发可以有效地抑制或杀灭粪肠球菌药物十分必要。     

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.     

根管治疗后疾病中粪肠球菌的致病性和检测及清除

粪肠球菌是根管治疗后疾病最常见的细菌,在再感染根管内的检出率为24%~77%。粪肠球菌的致病性与其形成的生物膜高度相关,而其耐药性也与其致病性密不可分,是引发根管内慢性感染的关键。粪肠球菌的检测以细菌培养和聚合酶链反应（PCR）为主,而PCR用于检测感染根管内粪肠球菌较细菌培养更为敏感。根管治疗后疾病中粪肠球菌的清除方法多种多样,结果各不相同。有研究显示抑菌率,质量分数2%的氯己定为100%,10%的盐酸氯丙嗪为88.8%,4%的利多卡因凝胶为76.4%和5%的盐酸阿米洛利为71.4%;有研究则显示,混合物-四环素-异构体-酸-去污剂、QMiX和次氯酸钠皆较2%氯己定更有效。还有研究显示,铒：钇-铝石榴石激光对粪肠球菌生物膜有清除作用。     

MTAD根管冲洗液对牙本质、牙釉质微硬度影响的研究

目的:评价MTAD根管冲洗液对牙本质、牙釉质微硬度的影响。方法:收集新鲜完整的前磨牙48个,截取牙冠并沿牙体长轴剖开,分别用30mL/L过氧化氢液、50g/L次氯酸钠液、MTAD液、13g/L次氯酸钠液处理牙本质、牙釉质5、15min,采用微硬度测定仪测定处理前、后两个时间点上牙本质、牙釉质的微硬度。结果:与30mL/L过氧化氢液和50g/L次氯酸钠液相比,使用MTAD液和13g/L次氯酸钠液处理后的牙本质、牙釉质微硬度的降低幅度不明显。结论:通过与30mL/L过氧化氢液、50g/L次氯酸钠液的对比研究发现,MTAD冲洗液对牙本质、牙釉质微硬度的影响明显小于前两者, 13g/L次氯酸钠冲洗液的影响与MTAD的相似,MTAD液联合13g/L次氯酸钠液的根管冲洗方法值得推荐。     

粪肠球菌生物膜细胞外聚合物的研究进展

粪肠球菌是根管治疗后再感染的主要致病菌,常以生物膜的形式存在。包绕在细菌周围或黏附在细菌表面的糖类、核酸和分泌蛋白对粪肠球菌的初始黏附、生物膜空间结构和细菌间信息交流等起重要的作用。本文就粪肠球菌生物膜及其细胞外聚合物组分和去除方法作一综述。     

Er:YAG激光联合次氯酸钠对粪肠球菌杀菌效果的研究

目的:比较掺铒钇铝-石榴石脉冲(Er:YAG)激光联合不同浓度次氯酸钠对根管内粪肠球菌杀菌效果的研究。方法:选择新鲜拔除的人单根管离体前磨牙建立粪肠球菌根管感染模型75个,随机分为5组,每组15个,分别进行如下处理:A组:5.25%次氯酸钠单独冲洗;B组:Er:YAG激光+5.25%次氯酸钠冲洗;C组:1%次氯酸钠单独冲洗;D组:Er:YAG激光+1%次氯酸钠冲洗。E组:空白对照。采集5组根管内的细菌进行培养计数并对结果进行卡方检验(Chi-square test)。结果:A、B、D三组均能完全杀灭根管内的粪肠球菌;C组未能完全杀灭根管内的粪肠球菌。15个培养皿中有11个可见粪肠球菌菌落。A、B、D三组间杀菌效果无差异且均显著优于C组。结论:高浓度次氯酸钠可以完全杀灭根管内的粪肠球菌,低浓度次氯酸钠不能完全杀灭根管内的粪肠球菌;Er:YAG激光可以显著增强低浓度次氯酸钠的杀菌作用。     

The effect of various concentrations of sodium hypochlorite on the ability of MTAD to remove the smear layer

Various organic acids, ultrasonic instruments, and lasers have been used to remove the smear layer from the surface of instrumented root canals. The purpose of this study was to investigate the effect of various concentrations of sodium hypochlorite (NaOCl) as an intracanal irrigant before the use of MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) as a final rise to remove the smear layer. Ten operators, using a combination of passive step-back and rotary 0.04 taper, nickel-titanium files, prepared 80 single- and multirooted human teeth. Distilled water, four different concentrations of NaOCl, or MTAD was used as intracanal irrigant. The canals were then treated for 2 min with 5 ml of one of the following solutions as a final rinse: 5.25% NaOCl, sterile distilled water, 17% EDTA, or MTAD. The presence or absence of smear layer and the amount of erosion on the surface of the root canal walls at the coronal, middle, and apical portion of each canal were examined under a scanning electron microscope. The results show that although MTAD removes most of the smear layer when used as an intracanal irrigant, some remnants of the organic component of the smear layer remain scattered on the surface of the root canal walls. The effectiveness of MTAD to completely remove the smear layer is enhanced when low concentrations of NaOCl are used as an intracanal irrigant before the use of MTAD as a final rinse. This regimen does not seem to significantly change the structure of the dentinal tubules.     

The antimicrobial effect of biopure MTAD on eight strains of Enterococcus faecalis: an in vitro investigation

The purpose of this investigation was to determine the antimicrobial effect of MTAD as a final irrigant on eight strains of Enterococcus faecalis (E. faecalis) and to measure the minimum inhibitory concentration (MIC) and the minimum lethal concentration (MLC) of MTAD. The roots of 240 extracted human teeth were instrumented using 1.3% NaOCl and 17% EDTA. The roots were divided into eight groups and contaminated with one of eight strains of E. faecalis. After irrigating with 1.3% NaOCl, the root canal and the external surfaces were exposed to MTAD for 5 minutes. Roots or dentin shavings were cultured to determine the growth of E. faecalis. The results showed that this treatment regimen was effective in completely eliminating growth in seven of eight strains of E. faecalis. The MIC/MLC tests showed that MTAD inhibited most strains of E. faecalis growth when diluted 1:8192 times and killed most strains of E. faecalis when diluted 1:512 times.     

Effect of 17% EDTA and MTAD on intracanal smear layer removal: A scanning electron microscopic study

The purpose of this study was to determine the effectiveness of MTAD as the final irrigant to remove the smear layer, compared with that of 17% EDTA, both following root canal irrigation with 5.25% sodium hypochlorite (NaOCl). Fifty‐five extracted maxillary and mandibular single‐rooted human teeth were prepared by a crown‐down technique using rotary 0.04 and 0.06 taper nickel‐titanium files. 5.25% sodium hypochlorite was used as the intracanal irrigant. The canals were then treated with 5 mL of one of the following solutions as final rinse: 5.25% sodium hypochlorite, 17% EDTA or MTAD. The presence or absence of smear layer in the coronal, middle and apical portion of each canal was examined with a scanning electron microscope. The results showed that MTAD is an effective final rinse solution for removing the smear layer in canals irrigated with sodium hypochlorite. When 17% EDTA was used as a final rinse, the smear layer was removed from the middle and coronal thirds of canal preparations, but it was less effective in the apical third of the canals.     

Antibacterial Efficacy of MTAD Final Rinse and Two Percent Chlorhexidine Gel Medication in Teeth with Apical Periodontitis: A Randomized Double-blinded Clinical Trial

IntroductionClinical assessment of the efficacy of novel root canal disinfection protocols is an important focus in endodontic research. This randomized double-blinded study assessed the antibacterial efficacy of a final rinse with BioPure MTAD (MTAD) and intracanal medication with 2% chlorhexidine gel (CHX) in teeth with apical periodontitis.MethodsCanals in 30 teeth (single-rooted and multi-rooted) were prepared by using 1.3% NaOCl, rinsed with MTAD or saline in random sequence, medicated with CHX for 7 days, irrigated with 1.3% NaOCl, and filled. Bacteriologic root canal samples were obtained by aspiration before (1A) and after (1B) canal preparation, after the final rinse (1C), after CHX was flushed (2A), and after final irrigation (2B). Bacteria were enumerated by epifluorescence-microscopy (EFM) by using 2 staining methods and by colony-forming-unit (CFU) counts after 14 days of incubation.ResultsBacterial counts (EFM) in 1B were greater than 95% decreased from 1A. Low bacterial densities in 1B, 1C, 2A, and 2B did not differ significantly from each other. EFM counts were consistently higher than CFU counts.ConclusionsThe final rinse with MTAD and medication with CHX did not reduce bacterial counts beyond levels achieved by canal preparation with NaOCl.     

The antimicrobial effect of MTAD: an in vitro investigation

Pulp and periradicular diseases are of microbial origin. To effectively clean the root canal system a disinfecting agent must be able to penetrate into difficult-to-reach areas and kill microorganisms with minimal damage to the host tissues. The purpose of this investigation was to test the ability of a mixture of a tetracycline isomer, an acid, and a detergent (MTAD) to kill Enterococcus faecalis and compare its efficacy to that of sodium hypochlorite (NaOCl) and ethylene diamine tetraacetic acid (EDTA). The zones of inhibition and minimum inhibitory concentrations were measured for these solutions. Measurement of zones of inhibition and determination of the minimum inhibitory concentrations showed that MTAD is as effective as 5.25% NaOCl and significantly more effective than EDTA (p < 0.0001). Furthermore, MTAD is significantly more effective in killing E. faecalis than NaOCl when the solutions are diluted (p < 0.0001). Measurement of the minimum inhibitory concentrations demonstrated that although MTAD is still effective in killing E. faecalis at 200x dilution, NaOCl ceases to exert its antibacterial activity beyond 32x dilution. EDTA did not exhibit any antibacterial activity. Based on the results of this study, it seems that MTAD is an effective solution in eradicating E. faecalis.     

The effects of calcium hydroxide removal methods on bond strength of Epiphany SE with two irrigation protocols

Abstract

Objective: The purpose of this study was to compare the effects of five calcium hydroxide removal methods on the bond strength of Epiphany SE sealer after canal irrigation with NaOCl+EDTA or NaOCl+MTAD. Materials and methods: The 120 roots were instrumented by using the ProTaper rotary system under irrigation with 2.5% sodium hypochlorite and randomly divided into two major groups according to the final irrigation: 1.3% NaOCl + MTAD and 5% NaOCl + 17% EDTA. For controls, 10 roots from each of the final irrigations with NaOCl + MTAD and NaOCl + EDTA (20 roots) were not filled with Ca(OH)₂. The intra-canal paste, Ca(OH)₂ was applied to each of the 100 remaining roots and stored at 37°C for 7 days. Each group was sub-divided into five sub-groups (n = 10) according to the removal technique for the intra-canal dressing: Group-1: recapitulation with size 30 K file + 3 ml of saline solution, Group-2: recapitulation with size 30 K file + 3 ml of 5% NaOCl, Group-3: using 5% NaOCl + 17% EDTA, Group-4: using 5%NaOCl + 15% citric acid, and Group-5: using 1.3% NaOCl + 5 ml MTAD. The root canals were filled with Resilon and Epiphany SE sealer. The bond strength was measured. Results: The mean bond strength of Epiphany SE to root dentine irrigated with NaOCl + MTAD was lower than that of NaOCl + EDTA. The highest bond strengths were 3.31 ± 0.057 and 2.60 ± 0.054 in the NaOCl + citric acid group when Ca(OH)₂ was applied to roots treated with NaOCl + EDTA and NaOCl + MTAD, respectively (p < 0.05). Conclusion: For root canals treated with NaOCl + EDTA or NaOCl + MTAD, the use of NaOCl + chelating agent for Ca(OH)₂ removal does not adversely affect the bond strength of Epiphany SE to dentin.     

Effect of MTAD on Enterococcus faecalis-contaminated root canals of extracted human teeth

The purpose of this investigation was to compare the antimicrobial effect of MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) with that of NaOCl with and without EDTA. Eighty-five extracted human teeth were contaminated with Enterococcus faecalis for 4 weeks. After biomechanical instrumentation using 1.3% or 5.25% NaOCl as root canal irrigant, the root canal and the external surface of each tooth were exposed to a 5-min application of MTAD, 1.3% NaOCl, 5.25% NaOCl or a 1-min application of EDTA followed by irrigation with 5 ml of 1.3% NaOCl or 5.25% NaOCl. Teeth or dentin shavings were cultured to determine presence or absence of the test bacteria. Fisher's exact test showed that the combination of 1.3% NaOCl as a root canal irrigant and MTAD as a final rinse was significantly more effective against E. faecalis than the other regimens. The chi2 test showed no difference between the other regimens.     

Evaluation of cytotoxicity of MTAD using the MTT-tetrazolium method

Previous studies have shown that MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) is an effective antibacterial irrigant as a final rinse to remove the smear layer from the instrumented surface of root canals. In this investigation we examined the cytotoxicity of MTAD compared with that of commonly used irrigants and medications. L929 fibroblasts were grown on cell culture plates and were placed in contact with various concentrations of test irrigants and medications. The cytotoxicity of these materials was evaluated 24 h after incubation using MTT assay. Means and standard deviations of absorbance were calculated for each group and statistically analyzed to determine presence or absence of significant difference between the means. The 50% inhibitory dose values were calculated, ranked, and statistically analyzed using the sign interval for median. Based on our results it seems that MTAD is less cytotoxic than eugenol, 3% H2O2, Ca(OH)2 paste, 5.25% NaOCl, Peridex, and EDTA and more cytotoxic than 2.63%, 1.31%, and 0.66% NaOCl.     

Reduction in antimicrobial substantivity of MTAD after initial sodium hypochlorite irrigation

Potential intrinsic tetracycline staining of intraradicular dentin has been observed when BioPure MTAD was employed as the final irrigant after initial rinsing with NaOCl. This study examined the effect of NaOCl-MTAD interaction on the antimicrobial substantivity of MTAD in dentin. Dentin cores previously irrigated with either MTAD, or in conjunction with 1.3% NaOCl as an initial irrigant were placed on blood agar plates inoculated with Escherichia faecalis at 10(5) cfu/ml. Dentin cores irrigated with 1.3% NaOCl only, and autoclaved dentin disks were used as the respective positive and negative controls. After anaerobic incubation, the mean diameter of bacterial inhibition zones formed around the MTAD group was significantly larger than the NaOCl/MTAD group, which, in turn, was not significantly different from the NaOCl positive control. Oxidation of MTAD by NaOCl resulted in the partial loss of antimicrobial substantivity in a manner similar to the peroxidation of tetracycline by reactive oxygen species.