Er:YAG激光在不同根尖工作宽度时对根管内粪肠球菌杀灭效果的研究

目的:观察Er:YAG激光在不同照射时间及不同根尖工作宽度时的杀菌效果。方法:取粪肠球菌感染根管模型125个,随机取10个样本用于检测根管壁细菌基线数。115个样本随机分为5组,1机械预备+Er:YAG激光+次氯酸钠(Na Cl O)组(n=40):根据根管预备型号再分为#20、#25、#30、#40 4个亚组(n=10),均用Er:YAG激光加52.5 g/L Na Cl O处理1 min;2机械预备+Na Cl O组(n=10):将根管预备至#40后,用52.5 g/L Na Cl O处理1 min;3Er:YAG激光+Na Cl O处理组(n=39):按激光处理时间分为E0(30 s)、E1(1 min)、E2(2 min)3个亚组后(n=13),向根管内注满52.5 g/L Na Cl O,并用Er:YAG激光照射相应时间;4阳性对照组(n=13):用3 m L 52.5 g/L Na Cl O处理根管1 min;5阴性对照组(n=13):用3 m L生理盐水处理根管1 min。处理结束后,分别采集各组根管壁表面和不同深度的牙本质碎屑进行细菌培养计数。结果:1Er:YAG激光+52.5 g/L Na Cl O组在根管壁各深度处的细菌减少率均显著高于阴、阳性对照组(P<0.05);E0、E1、E2组在根管壁表面和0~100μm深度处的细菌减少率基本相似(P>0.05),而在100~200μm和200~300μm处,E0组细菌减少率明显低于E1、E2组(P<0.05),E1和E2相比P>0.05。2#30/Er:YAG/Na Cl O组牙本质深层细菌减少率可达99%以上。#20/Er:YAG/Na Cl O组与#40/Na Cl O组比较P>0.05。结论:Er:YAG激光可增强Na Cl O的杀菌作用,在减少根尖预备工作宽度的同时可达到同样的杀菌效果。     

根尖工作宽度的研究进展

根管预备是根管治疗的关键步骤,精确测量根管根尖部初始宽度和确定根尖预备的终末工作宽度是高质量的根管预备必不可少的条件。恰当的根尖预备宽度应在尽可能保存牙体组织的前提下,彻底去除根管内的感染物质,达到根管最佳的清理和成形效果。本文对根尖预备工作宽度的观念、技术及存在的争议等作一综述。     

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.     

四种冲洗剂对根管内粪肠球菌清除效果的体外实验

目的比较常用的根管冲洗剂对根管内粪肠球菌感染的清除效果。方法建立粪肠球菌根管内感染模型，实验组用4种常用的化学冲洗剂、对照组用0．9％NaCl溶液冲洗根管。冲洗前、后计数根管内的细菌量，检测残余细菌并观察72h细菌复苏情况。结果化学冲洗剂的杀菌效果明显好于0．9％NaCl溶液（P〈0．05），2．5％次氯酸钠及2％氯己定明显好于3％H2O2（P〈0．05）。结论2％氯己定、2％氯胺-T的杀菌效果与2．5％次氯酸钠相似，3％H2O2杀菌效果较弱。     

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。     

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。     

粪肠球菌体外根尖生物膜模型的建立及形态学研究

目的 通过体外实验建立根尖生物膜模型,观察粪肠球菌根尖生物膜模型的形态及结构。方法 选取人新鲜拔除的单根离体牙24颗,随机分为8组,每组3颗,浸泡于粪肠球菌 ATCC 29212菌悬液中,分别于1、2、7d建立根尖生物膜模型。使用扫描电子显微镜（ SEM）观察生物膜形成过程;使用碘化丙啶（PI）和刀豆球蛋白 A异硫氰酸荧光素（ConA-FITC）对生物膜细菌及细胞外基质进行双染色,通过激光共聚焦扫描电子显微镜（CLSM）观察其形态和结构;计算生物膜覆盖率。结果 随时间的增加,根尖样本表面细菌覆盖面积增加,7d组与1、2d组间的差异存在统计学意义（P<0.05）, 1d与2d组间的差异无统计学意义（P>0.05）。 7d组形成生物膜结构,其样本表面的覆盖率为 17.23%±1.52%,样本表面有大量细菌附着,细菌被细胞外基质包绕,并呈群落分布。生物膜中的细菌被 PI染成红色,细胞外基质被 ConA-FITC染成绿色,可见多层次的空间结构以及亲水性通道。结论 粪肠球菌根尖生物膜于培养7d时形成完整的生物膜结构,由细菌群落及其周围大量的不定型基质组成。     

五种冲洗液对根管内粪肠球菌抗菌效果的体外实验

目的评价五种冲洗液对根管内粪肠球菌的杀菌效果。方法建立粪肠球菌根管内感染模型,将40个感染根管标本随机分为5组,每组8颗牙。器械预备时分别采用5.25%NaClO（A组）、2.5%NaClO（B组）、1%NaClO（C组）、17%EDTA（D组）、17%EDTA＋1%NaClO（E组）冲洗根管。冲洗前、冲洗后即刻及冲洗后72h分别取样,37℃下CO2孵育箱中培养,48h后计数菌落数（CFU/ml）。结果冲洗后5组根管内的粪肠球菌量均显著下降（P〈0.05）,其中A组与其余各组间差异均有显著性（P〈0.01）;B组与C组、D组间差异有显著性（P〈0.05）,与E组间差异无显著性（P〉0.05）;C组与D组、E组间差异有显著性（P〈0.05）;D组与E组间差异有显著性（P〈0.05）。根管冲洗后培养72h均有细菌生长。结论5.25%NaClO抗菌效果最强;17%EDTA＋1%NaClO的抗菌效果优于1%NaClO,与2.5%NaClO抗菌效果相近似。     

Er：YAG激光对根管内粪肠球菌影响的体外研究

目的本研究通过体外实验比较Er：YAG激光在不同频率的杀菌效果,及其在直根管及弯曲根管内的杀菌效果。方法选取50颗直单根管牙齿分F1、F2、F3、FP、FN 5组,比较Er：YAG激光在不同频率的杀菌效果;选取直根管30颗、弯曲根管20颗分5组比较Er：YAG激光对直根管及弯曲内粪肠球菌影响。建立粪肠球菌感染模型,FP组、E1组、E2组2.5%NaOCl溶液冲洗2min。FN组和E5组0.9%无菌生理盐水冲洗2min。其余各组根管内干燥后,激光照射12s,共4次,每次间隔10秒。根管消毒前后取样,检测粪肠球菌的菌落数目。结果①不同频率激光对根管内粪肠球菌影响的比较：冲洗或消毒后,F1组、F2组、F3组、FP组杀菌率两两比较没有统计学意义（P〉0.05）。②Er：YAG激光对直根管及弯曲内粪肠球菌影响的比较：冲洗或消毒后,E1、E2、E3组杀菌率分别为87.90%、87.02%和87.20%,两两比较没有统计学意义（P〉0.05）,但是E4组杀菌率为74.64%,与E1组、E2组、E3组两两比较有统计学意义（P〈0.05）。结论 Er：YAG激光是一种有效的根管消毒器械。不同频率的激光杀菌效果相似,但是在弯曲根管内的杀菌效果低于在直根管内。     

光活化消毒技术根管内消毒效果的研究

目的利用体外实验和临床试验评估光活化消毒技术（PAD）进行根管消毒的效果。方法体外选择30颗单根管牙根建立粪肠球菌ATCC29212感染模型,分为3组。用PAD技术进行根管消毒并取样,质量分数为2.5%的NaClO冲洗和生理盐水冲洗分别作为阳性和阴性对照组。临床选取50例慢性根尖周炎病例,随机分为2组。根管预备时质量分数为2.5%的NaClO溶液冲洗。预备后组1采用PAD消毒,组2用生理盐水冲洗。预备前后取样,所有样本接种于脑心浸液（BHI）培养基培养后记录菌落数。结果体外实验：PAD组细菌减少了99.86%,阳性对照组减少了100%,阴性对照组减少了96.94%。PAD组细菌回复10例均为阳性,阳性对照组6例,阴性对照组10例。临床试验：根管机械预备后细菌减少了99.98%。组1中PAD消毒后细菌培养均为阴性,组2细菌减少了36%。2组差异无统计学意义（P〉0.05）。结论 PAD单独使用可以降低根管内粪肠球菌的数量,但效果低于NaClO。临床PAD技术辅助根管预备可以进一步降低细菌的数量。     

Comparison of the Effectiveness of Three Irrigation Techniques in Reducing Intracanal Enterococcus faecalis Populations: An In Vitro Study

IntroductionSeveral irrigation techniques have been recently introduced with the main objective of improving root canal disinfection. This in vitro study aimed at comparing the intracanal bacterial reduction promoted by chemomechanical preparation with 3 different irrigation techniques.MethodsRoot canals from extracted teeth were contaminated with Enterococcus faecalis ATCC 29212 for 7 days and then randomly distributed into 3 experimental groups of 20 teeth each: group 1, conventional irrigation with NaviTip needles inserted up to 3 mm short of the working length; group 2, same as group 1, but supplemented with final irrigant activation by the EndoActivator system; and group 3, irrigation with the EndoVac system. NaOCl and ethylenediaminetetraacetic acid (EDTA) were the irrigants used in all experimental groups. The overall preparation time was kept constant for the groups, but the total volume ranged from 20 mL (groups 1 and 2) to 43 mL (group 3). The control group was irrigated with saline solution (total volume, 43 mL). Samples taken before and after chemomechanical procedures were cultured, and the colony-forming units (CFUs) were counted.ResultsReduction in the bacterial populations was highly significant for all groups. The 3 experimental groups with NaOCl and EDTA as irrigants were significantly more effective than the control group with saline in reducing CFU counts. There were no significant differences between the 3 techniques tested.ConclusionsThere was no evident antibacterial superiority of any of the irrigation techniques evaluated in the present in vitro model.     

In Vitro Evaluation of the Effectiveness of ProTaper Universal Rotary Retreatment System for Gutta-Percha Removal with or without a Solvent

IntroductionEffective removal of gutta-percha in endodontic retreatment is a significant factor to ensure a favorable outcome from failed procedures. The purpose of this study was to evaluate the efficacy of a nickel-titanium rotary instrument system with or without a solvent versus stainless steel hand files for gutta-percha removal.MethodsForty extracted human maxillary anterior teeth were prepared and filled. They were divided into 4 groups: Gates-Glidden and K-files, Gates-Glidden and K-files with chloroform, ProTaper Universal rotary retreatment system, and ProTaper Universal rotary retreatment system with chloroform. The operating time was recorded. The teeth were longitudinally sectioned and photographed. The images were analyzed and the filling remnants were quantified by using the IMAGE TOOL software.ResultsWith Kruskall-Wallis test, statistical analysis showed that there was no significant difference between the techniques in regard to the amount of the endodontic filling remnants (P < .05); however, the ProTaper Universal rotary retreatment system was faster than the hand files (P < .05).ConclusionsAll of the techniques proved helpful for the removal of endodontic filling material, and they were similar in material remaining after retreatment, but the ProTaper Universal rotary retreatment system without chloroform was faster.     

根尖预备尺寸对玷污层清除效果的比较研究

目的:比较5种不同根尖预备方案对根管玷污层的清除效果。方法:将50颗单根管上颌离体前牙随机分为5组,A组:采用机动ProTaper系统将根尖预备至25^#(F2),配合次氯酸钠+EDTA冲洗;B组:根尖预备至30^#(F3),预备及冲洗方法同A组;C组:采用机动ProTaper系统将根尖预备至F3,后用不锈钢K锉预备根尖至35^#,冲洗同A组;D组:采用机动ProTaper系统将根尖预备至F3,后用不锈钢K锉预备根尖至40^#,冲洗同A组;E组:根管预备同D组,冲洗用蒸馏水。利用热场发射扫描电子显微镜,评估玷污层清除情况。结果:B组、C组和D组均明显优于A组 (P<0.05);A组、B组、C组和D组明显优于对照E组(P<0.05)。结论:机动ProTaper将根管预备至30^#,可使足量的冲洗液渗入根尖1/3区,有效去除玷污层及碎屑。     

Effects of Intracanal Antimicrobials on Viability and Differentiation of Stem Cells From the Apical Papilla: An In Vitro Study

BackgroundRecent studies have indicated that intracanal antimicrobials used to disinfect the root canal in regenerative endodontic therapies (RETs) may be cytotoxic to stem cells from the apical papilla (SCAP), leading to inconsistent treatment outcomes. However, the effects of intracanal antimicrobial agents on the odontogenic differentiation capacity of SCAP at sub-lethal concentrations have not been investigated. The aim of this study was to determine the effects of intracanal antimicrobials on SCAP viability and odontogenic differentiation capacity using a clinically relevant concentration range (0.1–0.8 mg/mL).MethodsImmature human third molars were collected from 71 patients and the apical papillae were harvested to form single-cell suspensions. The cytotoxic effects of intracanal antimicrobials including double antibiotic paste (DAP), triple or modified-triple antibiotic paste (TAP or MTAP), and calcium hydroxide (Ca(OH)₂) on STRO-1⁺ SCAP were assessed using AlamarBlue and Live/Dead assays after exposing cells to treatment groups for 7 days at 0.1 to 0.8 mg/mL. The odontogenic differentiation potential of STRO-1⁺ SCAP was evaluated by immunocytochemistry staining of dentin matrix protein-1 and dentin sialophosphoprotein expression.ResultsAll concentrations of TAP significantly reduced STRO-1⁺ SCAP viability and odontogenic differentiation (P < .001), whereas no DAP concentrations were significantly cytotoxic. Ca(OH)₂ and MTAP concentrations below 0.4 mg/mL and 0.2 mg/mL, respectively, did not significantly reduce viability. The DAP, MTAP, and Ca(OH)₂ did not significantly impact the odontogenic differentiation capacity of STRO-1⁺ SCAP.ConclusionThe varying effects of intracanal antimicrobials on STRO-1⁺ SCAP in vitro suggest amendments to the current root canal disinfection protocol may improve the success of RETs.     

In Vitro Evaluation of the Effectiveness of Bleaching Agents Activated by Different Light Sources

Purpose: This study evaluated the efficacy of tooth whitening and color stability at different time periods after treatment.
Materials and Methods: Blocks obtained from human molars were divided into 15 groups (n = 5) by bleaching agents: 35% hydrogen peroxide (Whiteness HP and Opalescence Xtra) and 37% carbamide peroxide (Whiteness Super); and light sources: halogen lamp and plasma arc lamp (bleach mode), LED/diode laser, argon laser, and no light source. The efficacy of bleaching was measured using a spectrophotometer. Six bleaching sessions were performed (times 1 to 6). The specimens were submitted to another reading 7, 15, and 30 days after the end of bleaching (times 7, 8, and 9). The results were submitted to ANOVA followed by Tukey test and polynomial regression ( p < 0.05).
Results: Carbamide peroxide significantly differed from hydrogen peroxide, presenting low reflectance values. Activated versus non-activated bleaching did not differ significantly for any gel tested, except for Whiteness HP activated by argon laser, which presented the lowest mean reflectance values. The results obtained with hydrogen peroxide revealed a decrease in reflectance values one month after the end of treatment. For carbamide peroxide, this decrease was not observed.
Conclusion: The halogen lamp presented the same or higher efficacy than non-activated bleaching, which had a longer gel contact period. When hydrogen peroxide was used, a decrease in reflectance values was observed 30 days after the end of bleaching.     

两种根管消毒药物体外抑菌作用的比较研究

目的：探讨氢氧化钙制剂ApexCal、2%洗必泰（CHX）及两者配伍制剂对感染根管内常见菌的体外抑制作用。方法：采用琼脂扩散实验测定ApexCal、2%CHX及ApexCal与2%CHX1∶1混合对粪肠球菌、粘性放线菌、牙髓卟啉单胞菌、牙龈卟啉单胞菌和中间普氏菌形成的抑菌环直径并进行统计学比较。结果：2%洗必泰的抑菌作用显著高于ApexCal,ApexCal/2%CHX的抑菌作用显著低于2%CHX,但对粪肠球菌的抑菌作用明显优于Apex-Cal。结论：2%CHX和ApexCal/2%CHX可以作为有效的根管消毒剂,具有临床实用价值。     

Cytotoxicity and Genotoxicity of a New Intracanal Medicament, 2-hydroxyisocaproic Acid–An In Vitro Study

Introduction

A successful outcome of root canal therapy relies on effective disinfection of the root canal system, including the use of intracanal medicaments, which vary in their bactericidal and cytotoxic properties. Assessing the benefits and risks associated with the use of these medicaments is of extreme importance, especially in regenerative endodontic procedures, because residual stem cells may be harmed. In this study, we tested the cytotoxicity and genotoxicity of a novel agent, 2-hydroxyisocaproic acid (HICA), and compared its properties with those of a well-established medicament, calcium hydroxide.

In Vitro Evaluation of Five Core Materials

PURPOSE: This in vitro study determined the fracture strength of five core materials supported by two different endodontic dowels. Diametral tensile strength and microhardness of the three resin composite core materials used in this study were also tested. MATERIAL AND METHODS: The fracture strength study used one lanthanide-reinforced flowable resin composite (Ti-Core Auto E), one titanium- and lanthanide-reinforced composite (Ti-Core), one lanthanide-reinforced composite (Ti-Core Natural), and two metal-reinforced glass ionomer core materials (Ketac Silver and GC Miracle Mix). Two types of dowels were used: a multitiered, split-shank threaded dowel with a flange (#1 Flexi-Flange) and one without a flange design (#1 Flexi-Post). The specimens were divided into ten groups. Each tooth/dowel and core specimen was placed in a special jig at 45 degrees and subjected to a load by a universal testing machine. The diametral tensile strength and the microhardness of the three resin composite core materials were measured by a universal testing machine and Barcol hardness tester, respectively. All test groups contained ten specimens. RESULTS: The fracture strength value of the resin composite core materials was significantly larger ( p < 0.0001) than those for the metal-reinforced glass-ionomer core materials. Analysis of variance (ANOVA) also showed that the Flexi-Flange dowel interacted with Ti-Core and Ti-Core Auto E to significantly ( p < 0.0013) increase the fracture strength relative to the Flexi-Post. One-way ANOVA revealed that there were no significant differences between them in terms of diametral tensile strength. The Barcol hardness values of the composite core materials were statistically different ( p < 0.0001), with the Ti-Core the highest, followed by Ti-Core Natural, then Ti-Core Auto E. CONCLUSIONS: Resin composite core material performed better than glass ionomer material in this in vitro study. The flowable composite core material performed about the same in terms of fracture strength and diametral tensile strength compared with nonflowable composites. Combined with certain core materials, the flange design increased the fracture strength of the tooth/dowel and core combination.     

AHPlus和EndoREZ根管充填糊剂根尖封闭性能的体外研究

目的：采用体外离体牙实验,研究根管充填糊剂EndoREZ、AHPlus的根尖封闭性能。方法：收集60颗离体前牙,用镍钛旋转器械Protaper预备根管后,依据根管充填糊剂的不同,随机分为3组,每组20颗,A、B两组为实验组,分别用EndoREZ、AHPlus作为根管充填糊剂;C组为对照组,用氧化锌丁香油糊剂（ZOE）作为根管充填糊剂,3组均采用冷牙胶侧方加压法恰充填根管。将根管充填后的全部标本置于IndiaInk染料中进行根尖微渗漏实验,用染料渗透法结合透明牙体标本制作技术,检测染料渗透线长度,评价3种糊剂的根尖封闭性能。结果：A、B、C3组均有染料渗入根尖,渗透线长度分别为（1.13±0.24）mm,（0.94±0.18）mm,（1.79±0.12）mm;A、B、C3组间的染料渗透长度有显著性差异（P（0.01）,A、B两组与对照组间差异有统计学意义（P（0.05）,A组与B组间的差异无统计学意义。结论：树脂类根管充填糊剂AHPlus、EndoREZ的根尖封闭性能均优于氧化锌丁香油糊剂。