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。     

新型饵激光与超声对根管荡洗作用的对比研究

目的 比较Er:YAG激光中的SWEEPS 模式（shock wave enhanced emission photoacoustic streaming,SWEEPS）和超声非切割(passive ultrasonic irrigation,PUI) 两种荡洗方式对根管内粪肠球菌（Enterococcus faecalis,E. faecalis）生物膜的清除作用。 方法 选择人新鲜拔除的单根前磨牙共250颗,去除管壁玷污层,高温高压灭菌,建立E.faecalis感染模型。随机分为6组（n=40）,SWEEPS-Er:YAG激光联合3%NaClO,SWEEPS-Er:YAG 激光联合0.9%生理盐水,PUI联合3%NaClO,PUI联合0.9%生理盐水作为实验组,3%NaClO和0.9%生理盐水组作为对照组。扫描电镜(scanning electron microscopy,SEM)定性观察两种方式细菌清除作用,平板细菌计数法定量检测两种方式细菌减少率,非参数检验进行统计学分析。 结果 与荡洗前比,SWEEPS+NaClO组、SWEEPS+生理盐水、PUI+NaClO组、PUI+生理盐水组、3%NaClO组在荡洗后E. faecalis菌量显著降低（P＜0.05）,组间比较有统计学差异（P＜0.05）,细菌减少率SWEEPS+NaClO组>SWEEPS+生理盐水组>PUI+NaClO组>PUI+生理盐水组>NaClO组>生理盐水组。 结论 SWEEPS-Er:YAG激光荡洗对于根管内粪肠球菌生物膜的清除作用明显优于超声非切割荡洗。     

茶多酚、MTAD和次氯酸钠液抑制粪肠球菌及其生物膜的作用比较

目的:检测中药茶多酚、MTAD、52.5 g/L次氯酸钠抑制根管壁粪肠球菌生物膜的能力,并分析中药茶多酚作为根管冲洗液的可行性。方法:采用微孔板滴定法检测茶多酚,MTAD和52.5 g/L次氯酸钠液对粪肠球菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),采用琼脂扩散实验检测3种抗菌剂对粪肠球菌的抑菌圈。通过建立粪肠球菌感染根管3周和6周的模型,分别用茶多酚、MTAD和52.5 g/L次氯酸钠液对粪肠球菌感染后的根管进行处理,然后对根管壁生物膜中的细菌生存情况进行定性定量分析,比较这3种根管冲洗液抗粪肠球菌生物膜的能力。结果:MIC、MBC和琼脂扩散实验显示:3组冲洗剂对粪肠球菌均有抑制作用。在粪肠球菌感染根管3周的生物膜中,MTAD和次氯酸钠液可以完全抑制粪肠球菌生物膜,茶多酚处理后虽仍有粪肠球菌生长,但明显低于生理盐水处理组的细菌生存数,差异有统计学意义(P<0.05)。在粪肠球菌感染根管6周的生物膜中,次氯酸钠液可以完全抑制细菌生长,茶多酚和MTAD作用后仍有活菌生长,但与对照组相比,细菌生存数均显示了8个log值的下降,差异有统计学意义(P<0.05)。结论:52.5 g/L次氯酸钠液具有很强的抑制根管内粪肠球菌生物膜作用,而茶多酚和MTAD也具有一定的抑制粪肠球菌生物膜的能力。     

不同根管冲洗液和冲洗方法对粪肠球菌清除作用的体外研究

目的 比较不同冲洗液和冲洗方法对根管内粪肠球菌的清除效果。方法 建立120颗人完整单根管前磨牙粪肠球菌感染根管模型,随机分组,分别采用不同冲洗液(0.9% NaCl,0.5% NaClO,3% NaClO)及冲洗方法(注射针头冲洗,超声荡洗,RinsEndo系统处理,超声荡洗协同RinsEndo系统联用)进行根管清理。无菌吸潮纸尖取样,平板菌落计数法计算CFU值,计算细菌清除率,运用SPSS 22.0软件进行统计分析,P<0.05时差异具有统计学意义。结果 使用0.9% NaCl及0.5% NaClO冲洗液时,注射针头冲洗组细菌清除率明显低于超声荡洗及RinsEndo系统处理组(P<0.001);使用3% NaClO冲洗液的各组不同的冲洗方法,细菌清除率的差异无统计学意义(P=0.556)。而无论采用哪种冲洗方法,3% NaClO溶液的细菌清除效果均优于0.5% NaClO溶液和0.9% NaCl溶液(P<0.001)。结论 不同根管冲洗液在一定程度上会影响根管冲洗方法对根管内粪肠球菌的清除效果。     

PIPS联合纳米银对根管粪肠球菌抗菌效果研究

目的 探究激光引发光声流系统(PIPS)和纳米银(AgNPs)联合使用对根管内粪肠球菌生物膜的抗菌效果。方法 收集36颗单根管离体牙,建立粪肠球菌感染根管实验模型,将样本随机分成6组,采用0.9%NaCl、2%NaClO、0.1%AgNPs溶液分别联合传统手动冲洗(CNI)或PIPS对根管进行冲洗,使用菌落计数法测定治疗前后根管内粪肠球菌生物膜菌落数,并计算菌落计数减少的百分比。结果 所有实验组粪肠球菌生物膜的抑制效果均强于对照组(P<0.05),使用PIPS辅助0.9%NaCl、2%NaClO、0.1%AgNPs冲洗组的降幅均分别大于CNI辅助0.9%NaCl、2%NaClO、0.1%AgNPs冲洗组(P<0.05)。PIPS辅助0.1%AgNPs冲洗组的降幅明显大于PIPS辅助2%NaClO冲洗组(P<0.05)。结论 PIPS辅助AgNPs溶液冲洗可以显著提高根管内粪肠球菌生物膜的清除效果。     

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。     

高功率半导体激光对复杂根管消毒效果的体外研究

目的 评价高功率半导体激光联合次氯酸钠对体外复杂根管的消毒效果。方法 通过CBCT筛选含峡区的离体牙42颗，体外建立复杂根管感染模型，将离体牙随机分为4组，A组：半导体激光组+0.9% NaCl溶液； B组：半导体激光+5.25% NaClO； C组:5.25% NaClO； D组：空白对照组；每组10颗牙齿，经消毒处理后收集冲洗液，进行细菌培养、菌落形成单位计数、SEM观察及细菌活死染色后激光聚焦显微镜（ CLSM）观察分析，定量比较各组对粪肠球菌的杀灭效果。结果 ① A、B、C组处理后的杀菌率分别为33.9%、98.4%和82.8%，均高于D组的3.68%（ P<0.05）,其中B组杀菌率最高； ②扫描电镜结果显示：激光结合次氯酸钠组获得最好的根管壁清理效果； ③ CLSM图像荧光强度IOD值分析结果显示： B组红色荧光强度高于其余3组（ P<0.05）。结论 半导体激光辅助根管消毒有助于复杂根管（含峡区）的消毒；高功率（ 2.5 W）半导体激光结合传统根管化学消毒值得推广。     

不同冲洗方法对粪肠球菌感染根管的抗菌性研究

目的比较超声、Er,Cr：YSGG激光及Er：YAG激光辅助1%次氯酸钠（NaOCl）溶液冲洗对人离体牙根管表面粪肠球菌生物膜及根尖区不同深度牙本质小管内粪肠球菌的杀灭效果。 方法单直根管下颌前磨牙42颗,建立粪肠球菌生物膜感染的根管模型,采用随机字表法随机抽取2颗确定建成粪肠球菌生物膜感染根管模型,剩余40颗牙采用随机数字表法按随机对照原则分为5组,每组8颗。A组：5.25% NaOCl联合17%乙二胺四乙酸（EDTA）注射器冲洗;B组：0.9%氯化钠溶液注射器冲洗;C组：1% NaOCl溶液超声荡洗;D组：1% NaOCl溶液Er：YAG激光活化冲洗;E组：1% NaOCl溶液Er,Cr：YSGG激光活化冲洗。按分组进行处理后取样菌落计数,计算灭菌率。使用SPSS 17.0统计软件对实验数据进行方差齐性及正态性检验比较各组间和组内的灭菌率。 结果（1）组间比较：对根管壁表面,各组冲洗方法灭菌率比较,B组（5.74%）相似文献   

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。     

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。     

KaVo KEY激光对感染根管和根面粪肠球菌杀菌效果的体外研究

目的评价KaVo KEY激光对感染根管和根面粪肠球菌的杀菌效果。方法选用50颗人离体单根牙,建立粪肠球菌感染模型,随机分为3组,即空白对照组、激光组1和激光组2。激光组1和激光组2分别使用80、140 mJ能量激光照射整个根面,照射后再分别照射根管15、30 s。标本处理前与处理后即刻取样进行细菌培养计数。分别取激光处理后根管标本3个不同深度（100、200、300 μm）的牙本质碎屑培养24 h,比浊计数。结果激光处理后根管内和根面各组的细菌量均显著下降（P<0.05）,但各组间灭菌效果差异无统计学意义（P>0.05）。各个深度的牙本质碎屑培养24 h比浊显示80 mJ能量激光照射可清除100 μm处牙本质小管内的细菌,且照射15 s时差异有统计学意义（P<0.05）,其余组与空白对照组比较差异无统计学意义。结论KaVo KEY激光能有效杀灭感染根管内壁和根面的粪肠球菌;用低能量、短时间照射根管可有效清除浅层牙本质小管内的粪肠球菌。     

Nd:YAG激光和Er:YAG激光对根管内粪肠球菌杀灭效果的研究

［摘要］ 目的 观察Nd:YAG激光、Er:YAG激光及两者联用对根管内粪肠球菌的杀灭效果。方法 选取离体牙建立粪肠球菌感染模型,随机分为五组：A组：生理盐水组;B组：1%次氯酸钠溶液组;C组：Nd:YAG激光组;D组：Er:YAG激光组;E组：Nd:YAG激光+Er:YAG激光组。通过细菌培养和扫描电镜观察对比各组的杀菌效果。结果 细菌培养和扫描电镜结果显示：A组杀菌率最低,B组杀菌率最高,E组次高。除C组和D组间杀菌率相近外（P>0.05）,各组间均有统计学差异（P<0.05）。结论 Nd:YAG激光和Er:YAG激光均有一定的根管杀菌效果,两者联用效果更佳,可作为传统消毒方法的补充。     

根管预备尺寸对Er:YAG激光消毒效果的影响

目的 比较Er:YAG激光在不同根管预备尺寸情况下的消毒效果。方法 368颗离体上颌单直根管前牙,随机分为8组,机用K3镍钛锉预备至以下尺寸: A1组和B1组（#25/0.06）、A2组和B2组（#30/0.06）、A3组和B3组（#35/0.06）、A4组和B4组（#40/0.06）。高压灭菌后,A组接种粪肠球菌,B组接种白念菌。每组冲洗方法均为Er:YAG激光+3% NaOCl,Er:YAG激光+17% EDTA,Er:YAG激光+生理盐水,然后收集各组处理后根管壁表面微生物样本,进行微生物培养和计数,采用GraphPad Prism 5.02软件包分析各组绝对残留菌落数及菌落相对残留率。结果 Er:YAG激光对粪肠球菌与白念菌的消毒效果在预备尺寸为#40/0.06最佳,#35/0.06次之。#40/0.06、#35/0.06的消毒效果与#30/0.06、#25/0.06相比,差异显著（P＜0.05）。结论 在#25/0.06～#40/0.06根管尺寸范围内,Er:YAG激光联合3% NaOCl、17% EDTA和生理盐水冲洗上颌前牙单直根管时,根管预备尺寸不应小于#30/0.06。     

被动超声冲洗对弯曲根管的碎屑清理能力和根管形态的影响

目的: 评价被动超声冲洗在弯曲根管内碎屑清理能力和根管偏移量。方法: 选取下颌磨牙近中弯曲根管36个,弯曲度在25°以上,以机用 XP-endo Shaper根管锉预备根管。根据弯曲长度（curved length,CL）和冲洗方式分为A1组（CL>3 mm,注射器冲洗）、B1组（CL>3 mm,超声K锉冲洗）、C1组（CL>3 mm,irrisafe超声锉冲洗）、A2组（CL<3 mm,注射器冲洗）、B2组（CL<3 mm,超声K锉冲洗）和C2组（CL<3 mm,irrisafe超声锉冲洗）,每组6个样本。对所有样本冲洗前、后进行Micro-CT扫描,计算冲洗后根管内体积增加量和根管偏移量。采用SPSS 22.0软件包对数据进行统计学分析。结果: 在CL>3 mm的根管根尖区,PUI+irrisafe组的根管体积增量显著高于PUI+K锉和注射器冲洗（P<0.05）,并且在距离根尖孔5 mm处PUI+irrisafe形成的根管偏移量显著低于PUI+K锉（P<0.05）;与注射器冲洗相比无显著差异（P>0.05）。在CL<3 mm的根管中,PUI+irrisafe组和PUI+K锉组的根管体积增量均显著高于注射器冲洗（P<0.05）,但根管偏移量与注射器冲洗无显著差异（P<0.05）。结论: 在弯曲长度较大的根管中,被动超声冲洗结合预弯锉可获得更好的清理效果;而在弯曲长度较小的根管中,被动超声冲洗结合K锉和预弯锉均安全有效。     

Evaluation of the effectiveness of sodium hypochlorite used with three irrigation methods in the elimination of Enterococcus faecalis from the root canal, in vitro

The effectiveness of 4.0% sodium hypochlorite (NaOCl) used with three irrigation methods in the elimination of Enterococcus faecalis from the root canal was tested in vitro . Root canals contaminated with E. faecalis were treated as follows: (i) irrigation with 2 mL of NaOCl solution and agitation with hand files; (ii) irrigation with 2 mL of NaOCl solution and ultrasonic agitation; (iii) irrigation with NaOCl alternated with hydrogen peroxide. Contaminated canals irrigated with sterile saline solution served as the control. Paper points used to sample bacteria from the root canals were transferred to tubes containing 5 mL of brain heart infusion (BHI) broth. Tubes were incubated and the appearance of broth turbidity was indicative of bacteria remaining in the root canal. There were no statistically significant differences between the experimental groups. However, NaOCl applied by the three methods tested, was significantly more effective than the saline solution (control group) in disinfecting the root canal.     

Recovery of Enterococcus faecalis after single- or multiple-visit root canal treatments carried out in infected teeth ex vivo

AIM: To assess the presence of Enterococcus faecalis after root canal treatment in single or multiple visits in an ex vivo model. METHODOLOGY: Forty-five premolar teeth were infected ex vivo with E. faecalis for 60 days. The canals were then prepared using a crowndown technique with System GT and Gates-Glidden burs and irrigated with 2% chlorhexidine gel. The specimens were divided into five groups (G1, G2, G3, G4 and G5) according to the time elapsed between chemical-mechanical preparation and root canal filling, the irrigant solution used and the use or nonuse of a calcium hydroxide intra-canal medicament. The teeth were then root-filled and incubated for 60 days at 37 degrees C. Dentine chips were removed from the canal walls with sequential sterile round burs at low speed. The samples obtained with each bur were immediately collected in separate test tubes containing Brain-Heart Infusion broth. These samples were placed onto agar plates and colony forming units were counted after 24 h at 37 degrees C. Data were ranked and analysed using the Kruskal-Wallis statistical test. RESULTS: Enterococcus faecalis was recovered from 20% (three of 15 specimens) of G1 (chlorhexidine irrigation and immediate root filling in a single visit), 25% (four of 15 specimens) of G2 (chlorhexidine irrigation and filling after 14 days use of a calcium hydroxide dressing in multiple visits), 40% (two of five specimens) of G3 (chlorhexidine irrigation and filling after 7 days), 60% (three of five specimens) of G4 (saline irrigation and filling after 7 days) and from 100% (five of five specimens) of G5 (saline irrigation and immediate filling without sealer). CONCLUSIONS: Neither single- nor multiple-visit root canal treatment ex vivo, eliminated E. faecalis completely from dentinal tubules. Up to 60 days after root filling, E. faecalis remained viable inside dentinal tubules. When no sealer was used, E. faecalis presented a higher growth rate.     

Additive effect of a diode laser on the antibacterial activity of 2.5% NaOCl, 2% CHX and MTAD against Enterococcus faecalis contaminating root canals: an in vitro study

This in vitro study was performed to evaluate the effect of a diode laser and common disinfectants used in combination on mono-infected dental canals. One hundred and six single-rooted human premolars were prepared and contaminated with Enterococcus faecalis. After two weeks of incubation, samples were divided into two experimental groups (n = 48) and two control groups (n = 5). In the first group, the teeth were rinsed for 5 min with either sterile saline, 2.5% NaOCl, or MTAD, or for 1 min with 2% chlorhexidine gluconate (CHX). In the other group, samples were additionally irradiated with a 810-nm diode laser at 2 W output for 5 × 5 s. Intracanal bacterial sampling was done, and the samples were plated to determine the CFU count. In the first group, 2.5% NaOCl was as effective as 2% CHX and significantly more effective than MTAD (P < 0.008). In the second group, either MTAD, 2% CHX or 2.5% NaOCl in combination with laser treatment had a similar effect. Absence of growth was seen only for MTAD plus laser treatment. Complete elimination of E. faecalis was seen only for the combination of MTAD with diode laser irradiation. Combination therapy with MTAD irrigation and diode laser irradiation, within the parameters used in this study, can be recommended as an effective treatment option for complete elimination of E. faecalis from the root canal system.     

Bactericidal efficacy of Er,Cr:YSGG laser irradiation against Enterococcus faecalis compared with NaOCl irrigation: an ex vivo pilot study

AIM: To compare the efficacy of a standard NaOCl irrigation procedure with that of Er,Cr:YSGG laser irradiation in contaminated root canals having small and large apical foramina. METHODOLOGY: Forty root canals of extracted central incisor teeth with straight roots were chosen so that their apical foramina just permitted the tip of a size 20-K file to pass through. The canals were then enlarged with files to size 60 and randomly divided into four groups of 10 teeth each. The apical foramina of one group were widened further so that the tip of a size 45-K file could just pass through. After sterilization, all roots were inoculated with Enterococcus faecalis for 48 h at 37 degrees C. The first group was used as a control, the second group was irrigated with 3% NaOCl solution for 15 min, and the last two groups having different sizes of apical foramina were irradiated with the Er,Cr:YSGG laser at output power from 0.5 W, with 20% air and water levels. The disinfecting efficacy of the groups was tested by collecting dentine chips from the inner canal walls of the specimens and counting viable E. faecalis on Mueller-Hinton agar plates. RESULTS: The differences in the mean number of viable colonies between the control and laser groups were statistically significant (P < 0.05). The control specimens had the highest number of microorganisms (153 x 10(3) +/- 39 x 10(3)). Complete sterilization was achieved in the 3% NaOCl group. The mean colony forming units (CFU) values obtained after Er,Cr:YSGG laser irradiation were 6.6 x 10(3) CFU and 6.5 x 10(3) CFU in root canals having large and small apical foramina respectively. CONCLUSION: In teeth with straight roots the Er,Cr:YSGG laser reduced the viable microbial population in root canals with small and large apical foramina but did not eradicate all bacteria. Three percent NaOCl inhibited the growth of E. faecalis and effectively sterilized all root canals.     

Ex Vivo Evaluation of the Efficacy of Photodynamic Therapy in Eliminating Enterococcus faecalis from Dentinal Tubules by Confocal Laser Scanning Microscopy

IntroductionThe aim of the present study was to investigate ex vivo by confocal laser scanning microscopy the antibacterial effect of photodynamic therapy (PDT) on dentinal tubules in the apical 5 mm of human mandibular premolars contaminated with Enterococcus faecalis.MethodsThirty-four teeth were standardized to 20 mm and foraminal anatomic diameters using a #20 K-file (Dentsply Maillefer). Samples were contaminated for 21 days and divided into the following 3 experimental groups (n = 10): the PDT group (instrumented canals and PDT), the passive ultrasonic irrigation (PUI) group (instrumented canals and PUI), and the PUI-PDT group (instrumented canals, PUI, and PDT), along with a control group (n = 4) (noninstrumented canals). The canals in the experimental groups were instrumented with ProTaper Next (Dentsply Maillefer) up to X3 and rinsed with EDTA and sodium hypochlorite. The photosensitizer used was 0.01% methylene blue with a preirradiation time of 5 minutes and a diode laser with 4 J energy and a 660-nm wavelength. Cross sections were made 5 mm from the apex of all samples, which were analyzed using confocal laser scanning microscopy. The results were analyzed using the Shapiro-Wilk and Kruskal-Wallis (Dunn) tests.ResultsThere was a lower percentage of live bacteria in the PUI-PDT group, with a statistical difference compared with the control and PDT groups (P < .05). There was no statistical difference in the percentage of live bacteria between PUI-PDT and PUI (P > .05).ConclusionsIt was concluded that the PUI-PDT association was most effective in disinfecting root canals compared with the control group and PDT.