Elimination Of Enterococcus Faecalis Research Articles

The Effectiveness of Three Different Irrigant Activation Methods in the Elimination of Enterococcus faecalis from Root Canals.

Background and Objective: Eliminating intracanal Enterococcus faecalis (E. faecalis) is challenging because of its ability to penetrate deep dentinal tubules and its high resistance to many chemicals. This study evaluated the effectiveness of conventional needle irrigation and three different irrigant activation methods in reducing E. faecalis. Methods: The root canals of extracted teeth were shaped, contaminated with E. faecalis, and incubated for three weeks. They were randomly allocated to four experimental groups of 15 teeth each according to the final irrigation method: group 1, conventional needle irrigation; group 2, passive ultrasonic (PU) irrigation; group 3, XP-endo Finisher (XPF); and group 4, laser-activated (LA) irrigation. Bacterial samples were taken and cultured before and after these final irrigation procedures. The colony-forming units were counted, and the bacterial reduction percentages of each group were calculated. The Kruskal-Wallis and Dunnet tests were used for statistical analysis. Results: All irrigant activation methods were significantly more effective than conventional needle irrigation. Although the LA group generated more negative samples than PU, there was no statistically significant difference between the LA and PU groups. LA was significantly more effective than the XPF, whereas PU and XPF were statistically similar. Conclusions: Within the limitations of this study, the final irrigation with LA and PU showed the best reductive effect on E. faecalis colonies. Considering that the LA group had more negative samples, it may be chosen as an alternative to enhance root canal disinfection, especially in difficult cases.

Comparative evaluation of antimicrobial efficacy of chitosan nanoparticles and calcium hydroxide against endodontic biofilm of Enterococcus faecalis: An in vitro study

Aim: The aim of the study was to assess and evaluate the antimicrobial effectiveness of chitosan nanoparticles (CSNPs) with calcium hydroxide in the elimination of Enterococcus faecalis. Materials and Methods: Using the broth microdilution method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of calcium hydroxide and CSNPs were measured. The antibiofilm effect of calcium hydroxide and CSNPs against E. faecalis biofilm was qualitatively analyzed using a crystal violet assay. A 7-day-old biofilms of E. faecalis grown on dentine discs were assigned to the following three groups (n = 11 dentine discs), normal saline (group I), calcium hydroxide (group II), and CSNPs (group III). Quantification of live and dead cells using confocal microscopy was done to evaluate the antibiofilm efficacy of the medicaments included in the study. Results: MIC of calcium hydroxide and CSNPs against E. faecalis was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. MBC of calcium hydroxide and CSNPs was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. Using Crystal Violet (CV) assay, calcium hydroxide and CSNPs showed biofilm inhibition at concentrations of 2.5 mg/mL and 0.625 mg/mL, respectively. Confocal laser scanning microscopy analysis found that both calcium hydroxide and CSNPs showed a significant decrease in viable cells at their MBC values compared to the control group’s normal saline. CSNPs showed a significantly lower percentage of live cells than calcium hydroxide (P < 0.05). Conclusion: The study results reveal that the antimicrobial efficacy of CSNPs is better than calcium hydroxide and normal saline against E. faecalis biofilm.

Comparative evaluation of antimicrobial efficacy of chitosan nanoparticles and calcium hydroxide against endodontic biofilm of Enterococcus faecalis: An in vitro study

Aim: The aim of the study was to assess and evaluate the antimicrobial effectiveness of chitosan nanoparticles (CSNPs) with calcium hydroxide in the elimination of Enterococcus faecalis. Materials and Methods: Using the broth microdilution method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of calcium hydroxide and CSNPs were measured. The antibiofilm effect of calcium hydroxide and CSNPs against E. faecalis biofilm was qualitatively analyzed using a crystal violet assay. A 7-day-old biofilms of E. faecalis grown on dentine discs were assigned to the following three groups (n = 11 dentine discs), normal saline (group I), calcium hydroxide (group II), and CSNPs (group III). Quantification of live and dead cells using confocal microscopy was done to evaluate the antibiofilm efficacy of the medicaments included in the study. Results: MIC of calcium hydroxide and CSNPs against E. faecalis was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. MBC of calcium hydroxide and CSNPs was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. Using Crystal Violet (CV) assay, calcium hydroxide and CSNPs showed biofilm inhibition at concentrations of 2.5 mg/mL and 0.625 mg/mL, respectively. Confocal laser scanning microscopy analysis found that both calcium hydroxide and CSNPs showed a significant decrease in viable cells at their MBC values compared to the control group’s normal saline. CSNPs showed a significantly lower percentage of live cells than calcium hydroxide (P < 0.05). Conclusion: The study results reveal that the antimicrobial efficacy of CSNPs is better than calcium hydroxide and normal saline against E. faecalis biofilm.

Antimicrobial Efficacy of Different Concentrations of Sodium Hypochlorite in the Elimination of Enterococcus Faecalis: An In-vitro Study

Introduction: Primary teeth are equally important as permanent teeth. Endodontic therapy aids in the preservation and maintenance of extremely carious primary teeth. For root canal therapy to be successful, root canals must be properly prepared and effectively irrigated. Sodium Hypochlorite (NaOCl) has been the gold standard for root canal treatment of primary teeth. However, there are a few drawbacks to using higher concentrations of sodium hypochlorite, such as toxic reactions from its apical penetration. In addition, an excess of irrigation fluid via the apical region could harm the permanent tooth underneath. Therefore, it is crucial to select the proper concentration to preserve the delicate balance between effectiveness and safety. Aim: The present in-vitro study was conducted in the city of Chennai, Tamil Nadu, between March and June 2022. The study aimed to evaluate the effectiveness of lower concentrations of sodium hypochlorite, such as 1%, 0.5%, and 0.25%, against Enterococcus faecalis. Materials and Methods: The antibacterial activity of different concentrations of sodium hypochlorite (1%, 0.5%, and 0.25%) against Enterococcus faecalis was performed using Muller Hinton agar. Three Mueller Hinton agar plates were prepared and sterilised for 15 minutes for each concentration. The volumes used were 25 μL, 50 μL, and 100 μL, respectively. E. faecalis was swabbed and poured into the sterilised plates. The plates were incubated for 24 hours at 37°C. After incubation, the plates were examined, and their zone of Inhibition was determined. ANOVA test was applied with Post-hoc Tukey’s analysis. Results: One-way ANOVA test showed that there was a significant difference with a p-value <0.001 in all three groups. Post-hoc Tukey’s analysis was done, and the test showed that the highest zone of inhibition was seen with 1% sodium hypochlorite at 100 μL, with zone diameter of 39 mm, and the least zone of inhibition was seen with 0.25% sodium hypochlorite solution at 25 μL, with zone diamter of 22 mm. Conclusion: The results of the present study show that a 1% sodium hypochlorite solution can be used to successfully disinfect root canals, indicating its potential as an effective antimicrobial agent in endodontic procedures.

Impact of Different Access Cavity Designs and Ni–Ti Files on the Elimination of Enterococcus faecalis from the Root Canal System: An In Vitro Study

The present research aimed to reveal the in vitro effects of different endodontic file systems utilizing different endodontic access cavity designs on the elimination of Enterococcus faecalis from root canal systems. One hundred and fifty mandibular molar teeth were separated into three groups with respect to the access cavity design: traditional endodontic cavity (TEC), conservative endodontic cavity (CEC), and truss access cavity (TAC) (n = 50). After access cavity preparation, inolulation of teeth with E. faecalis was undertaken for 21 days. Following the first sampling (S1), further division of the groups into five subgroups (n = 10) was performed: ProTaper Gold, 2Shape, TruNatomy, Reciproc Blue, and WaveOne Gold. After instrumentation, bacterial sampling (S2) was performed. Bacterial reduction was evaluated in colony-forming units/mL, and statistical analysis was carried out. The E. faecalis count decreased significantly in all groups (p < 0.05). The range of mean values for a decrease in E. faecalis in log numbers was lowest in the TAC and Reciproc Blue groups, while the highest values of bacterial reduction were detected in the TEC and ProTaper Gold groups. The highest level of antibacterial action was obtained with the use of ProTaper Gold compared to the other file systems tested.

Antimicrobial Effectiveness of Photodynamic Therapy, 5% Sodium Hypochlorite and 2% Chlorhexidine Gluconate in Root Canal Treated Teeth: A Clinical Study

Aim: To evaluate the effectiveness of photodynamic therapy (PDT), sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHO) in the endodontic re-treatment in the removing of microorganisms from previously filled infected root canals. Materials and Methods: The study samples consist of 54 root canal treated anterior teeth with apical periodontitis were randomly divided into three groups according to the disinfection protocol. Microbiological samples from the root canals were collected after removing the gutta-percha (S1) and following the endodontic re-treatment (S2) with either 5% NaOCl, 2% CHO or PDT procedure for 1 minute. Microbiological samples were cultivated on selective plates to assess the presence or absence of microbial growth and determine the average reduction of viable microorganisms. Results: Significant reduction in the total bacterial count in all the groups at post treatment ( P < .001). PDT provided statistically higher (99.74%) elimination of Enterococcus faecalis in comparison to NaOCl (95%) and CHO (88%). Conclusions: The use of PDT in endodontic re-treatment led to the significant reduction of the remaining bacterial species. So, PDT can be used for routine endodontic disinfection in failed root canal cases.

Efectividad del sistema rotatorio Mtwo® e hipoclorito de sodio en la eliminación del Enterococcus faecalis. Revisión de la literatura

El objetivo de este estudio fue determinar la efectividad del sistema rotatorio Mtwo® y del hipoclorito de sodio en la eliminación de Enterococcus faecalis.Se realizó una revisión de la literatura de estudios experimentales In vitro y Ex vivo, publicados desde 2010 hasta 2020 en las bases de datos MEDLINE/PubMed, EBSCOhost y Scopus, disponibles en texto completo, publicados en español e inglés. Se seleccionaron los artículos de acuerdo con los criterios establecidos y se analizó el contenido de cada uno de ellos por medio de una tabla matriz en la cual se incluyeron los principales hallazgos.Se identificaron cuarenta y cuatro artículos, de los cuales se incluyeron cinco estudios. La efectividad de la solución irrigadora (NaOCl) demostró resultados a concentraciones de 2.5% y 5.25% y la aplicación del sistema rotatorio Mtwo® reportó disminución del recuento bacteriano al compararlo con otros métodos de instrumentación, así como un recrecimiento menor de bacterias después del tratamiento con este sistema.Las concentraciones de hipoclorito de sodio al 2,5% y al 5,25% y el uso del sistema de instrumentación Mtwo® son eficaces en la eliminación del Enterococcus faecalis.

Evaluation of the Effect of Enlargement of the Apical One Third by Protaper Universal Rotary Files System on Elimination of Enterococcus faecalis and Surface Irregularities in Single Canaled Premolars (A ComparativeIn-Vitro Study)

Evaluation of the Effect of Enlargement of the Apical One Third by Protaper Universal Rotary Files System on Elimination of Enterococcus faecalis and Surface Irregularities in Single Canaled Premolars (A ComparativeIn-Vitro Study)

In Vitro Comparative Evaluation of Effectiveness of Sodium Hypochlorite with Conventional Irrigation Method versus EndoVac and Ultrasonic Irrigation in the Elimination of Enterococcus faecalis from Root Canals.

ABSTRACTAim:The aim of this study was to compare the decrease in bacterial population in the root canals with 2.5% sodium hypochlorite (NaOCl) and three irrigation systems: Conventional Needle Irrigation, Passive Ultrasonic Irrigation, and EndoVac Apical Negative Pressure Irrigation systemMaterials and Methods:Access open was carried out in 48 extracted single-rooted maxillary and mandibular human premolar teeth. The canals were instrumented 1 mm short of apical foramen up to No. 50 size file; irrigated and apical foramen was sealed with cyanoacrylate. The teeth were mounted in plaster and autoclaved for 20 min at 121°C. The plaster blocks containing the teeth were inoculated with Enterococcus faecalis and incubated at 37°C for 24 h. The specimens divided randomly into four groups (n = 12) depending on the type of irrigation system used: Group 1: Conventional Irrigation Needle, Group 2: Ultrasonic system, Group 3: EndoVac Negative Pressure Irrigation system used with 2.5% NaOCl, and Group 4: Control group, normal saline irrigation. The normal saline is used as control. The samples were collected using 45 size sterile paper points and quantitative bacterial assessment was carried out by seeding each dilution on plates containing brain heart infusion broth. Then, incubated at 37°C for 7 days and colony-forming units were counted. Data obtained were statistically analyzed.Results:Statistically, EndoVac irrigation systems were more effective in reducing the number of bacteria than the other irrigation systems.Conclusion:EndoVac irrigation system was more effective in reducing bacterial numbers in infected root canals than the other two irrigation systems.

Investigation of different sodium hypochlorite volumes, concentrations and times of irrigation in endodontic therapy: a systematic review

Investigation of different sodium hypochlorite volumes, concentrations and times of irrigation in endodontic therapy: a systematic review

Effect of an Er:YAG laser combined with sodium hypochlorite on the elimination of Enterococcus faecalis in the root canal

Effect of an Er:YAG laser combined with sodium hypochlorite on the elimination of Enterococcus faecalis in the root canal

Effect of a passive sonic irrigation system on elimination of Enterococcus faecalis from root canal systems of primary teeth, using different concentrations of sodium hypochlorite: An in vitro evaluation.

Background. This in vitro study aimed to compare the antibacterial effect of different concentrations of sodium hypochlorite on elimination of Enterococcus faecalis from root canal systems of primary teeth with or without a passive sonic irrigation system (EndoActivator). Methods. The root canals of 120 extracted single-rooted primary incisors were prepared using the crown-down technique. The teeth were autoclaved and inoculated with E. faecalis. The infected samples were then randomly divided into 6 experimental groups of 15 and positive and negative control groups as follows: group 1: 0.5% sodium hypochlorite solution; group 2: 2.5% sodium hypochlorite solution; group 3: 5% sodium hypochlorite solution; group 4: 0.5% sodium hypochlorite solution + sonic activation; group 5: 2.5% sodium hypochlorite solution + sonic activation; and group 6: 5% sodium hypochlorite solution + sonic activation. Microbiological samples were collected before and after disinfection procedures and the colony-forming units were counted. Statistical analyses were performed using the two-way ANOVA and post hoc Duncan's tests in cases of significant difference. Results. There were no significant differences between the groups in any of the variables (concentration of antiseptic or use of sonic irrigation system). Conclusion. Use of passive sonic irrigation systems in endodontic treatment of single-rooted primary teeth is of no benefit compared to regular needle irrigation. The results of this study also recommends use of lower concentrations of sodium hypochlorite solution (0.5%) for irrigation of the root canal system rather than higher concentrations given approximately equal efficacy.

Efficacy of calcium oxide and calcium hydroxide nanoparticles on the elimination of Enterococcus faecalis in human root dentin.

The objective of this study was to compare the antibacterial effect of calcium oxide nanoparticles (CONPs) and calcium hydroxide nanoparticles (CHNPs) against Enterococcus faecalis in a dentinal block model. E. faecalis strain JCM 7783 was introduced into dentinal tubules of semicylindrical dentin specimens by centrifugation and incubated for 1week. Fifty microliters of CONPs or CHNPs was placed on the root canal side of the infected dentin specimens. The specimens were then incubated in aerobic condition at 37°C and 100% relative humidity for 1week. The treated dentin specimens were subjected to fluorescent staining and confocal laser scanning microscopy (CLSM) to analyze the proportions of non-vital and vital bacterial cells inside the dentinal tubules. Scanning electron microscopy (SEM) was used to confirm the effect of the medicaments on the bacteria in the dentinal tubules. Calcium oxide (CO) and calcium hydroxide (CH) were used as controls. Based on the CLSM and SEM analyses, CHNPs were more efficient than CONPs in the elimination of the bacteria in the dentinal tubules. CONPs significantly killed more E. faecalis than CO and CH (P < .05). Neither CO nor CH was able to kill the bacteria. CHNPs were more effective than CONPs in the elimination of E. faecalis in dentinal tubules. CHNPs are effective nanoparticles in killing endodontic bacteria present in dentinal tubules. They have potential as an intracanal medicament, which may be beneficial in root canal therapy.

The effect of different root canal medicaments on the elimination of Enterococcus faecalis ex vivo.

Objective:The aim of this study was to evaluate the antimicrobial effect of chlorhexidine gel (CHX-G) 2%, chlorhexidine powder (CHX-P) 1%, povidone-iodine (PVP-I), polyhexanide and camphorated-and-mentholated chlorophenol (ChKM) ex vivo.Materials and Methods:For every medicament group 10 root segments (15 mm long) of extracted human teeth were prepared to ISO-size 45 and sterilized (n = 50). The root segments were then inoculated with Enterococcus faecalis and aerobically incubated at 37°C. After 1 week, ten root canals were filled with one of the medicaments, respectively and aerobically incubated at 37°C for another week. Ten teeth served as positive controls and were filled with sterile saline solution. After 7 days, the medicaments were inactivated and all root canals were instrumented to ISO-size 50. The obtained dentin samples were dispersed in Ringer solution followed by the preparation of serial dilutions. 10 μl per sample were applied to an agar plate and incubated at 37°C for 48 h. The colony forming units were counted and the reduction factors (RFs) were calculated and statistically analyzed.Results:Compared with the positive controls all medicaments exhibited an antibacterial effect against E. faecalis. The RFs for CHX-G, CHX-P and ChKM were significantly higher compared to PVP-I and polyhexanide (P < 0.05). In contrast to PVP-I and polyhexanide, CHX-G, CHX-P and ChKM were able to eliminate E. faecalis from all dentin samples.Conclusions:Within the limitations of this ex vivo investigation, 2% CHX-G and CHX-P were as effective as ChKM against E. faecalis. Thus, when choosing a root canal medicament the better biocompatibility of CHX compared with ChKM should be taken in consideration.

Utjecaj poliheksametilenova bigvanida na mikroorganizme u korijenskom kanalu zuba

The objective of this study was to test the effectiveness of 0.2% polyhexamethylen biguanide in the elimination of Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans and compare it with effectiveness of 2.5% sodium hypochlorite. Crown and apical portion of forty- eight single-rooted human teeth was removed and the root canals instrumented with Hedstrom files up to size 40. Sixteen specimens were inoculated with an overnight broth culture of E.faecalis (ATCC 51299), P.aeruginosa (ATCC27853) and C.albicans (clinical isolate). After 48 h incubation and irrigation with saline, dentine samples were collected from root canal walls with Hedstrom files size 50 before and after irrigation with 0.2% PHMB and 2.5% NaOCl followed by irrigation with neutralizer and saline. Samples were put into vials containing 2 mL of sterile saline and tenfold dilution, and plated on blood agar after 30 s vortexing. Colony forming units (CFU) were counted after 48 h incubation at 37oC. For statistical analysis Kruskal-Wallis test (p<0.05) was used. Results: After treatment with PHMB P.aeruginosa was eradicated from all samples, E.faecalis was also reduced and C.albicans was not grown in seven out of eleven samples. NaOCl was less effective than PHMB on E.faecalis (p=0.630) and P.aeruginosa (p=0.138), especially in case of C.albicans (p=0.01). 0.2% PHMB effectively reduced the number of E.faecalis and P.aeruginosa as well as 2.5% NaOCl). On C.albicans 0.2% PHMB showed better antimicrobial effect than 2.5% NaOCl. Further studies will be necessary to determine PHMB's effectiveness on mature biofilm and its biocompatibility.

An evaluation of antibacterial efficacy of 3% sodium hypochlorite, high-frequency alternating current and 2% chlorhexidine on Enterococcus faecalis: An in vitro study.

Aim:The purpose of this study was to evaluate the antibacterial efficacy of 3% sodium hypochlorite (NaOCl), high-frequency alternating current (HFAC) (Endox Endodontic System), 2% chlorhexidine (CHX) in elimination of Enterococcus faecalis from experimentally infected root canals, in vitro.Materials and Methods:Eighty extracted, single rooted permanent upper anterior teeth were instrumented up to size 50, teeth were sterilized and inoculated with E. faecalis, subcultured in BHI broth which had its optical density adjusted to approximately 1.5Χ108 colony forming units (CFUs) ml-1 by comparing its turbidity to a McFarland 0.5 BaSO4 standard solution. After incubation for 24 h, the contaminated root canals were divided into four groups and subjected to action of NaOCl 3%, CHX 2%, and HFAC with physiological saline as a positive control. Sterile paper points were selected to take the sample of the bacteria and transferred to tubes containing 5ml of BHI broth and then incubated for 24 and 48 h, followed by agar plating of the resultant broth turbidity on Enterococcus confirmatory agar.Results:Data obtained were analyzed statistically for differences using chi-squared test, comparing different groups, with a significance level established at P<0.05 and 3% NaOCl showed no growth postoperatively, CHX and HFAC showed reduction of postoperative growth compared to physiological saline and, were statistically significant (P<0.05).Conclusion:In the present study, sodium hypochlorite, CHX, HFAC all were significantly effective in eliminating E. faecalis and sodium hypochlorite showed the maximum anti-bacterial activity against E. faecalis.

Evaluation ofEnterococcus faecalisremoval efficacy of the EndoVac® and EndoActivator® intracanal irrigation methods

The aim of this study was to evaluate endodontic irrigation methods with and in the elimination of Enterococcus faecalis from the root canals. Extracted 70 human single-rooted teeth were used. The canals were instrumented by a crown-down technique with .04 taper ProFile to ISO size 40. After the teeth were autoclaved, the canals were inoculated with E. faecalis and incubated for 48 h. The teeth were randomly divided into three experimental groups of 20 teeth each according to canal irrigation methods and two control groups as follows: group 1 - ; group 2 - ; group 3-Conventional needle irrigation method. After canal irrigation using 2.5% NaOCl. first samples (S1) were taken using sterile paper point. And the canals were filled with sterile brain heart infusion (BHI) broth and incubated for 24 h, then second samples (S2) were taken. The samples were cultured on BHI agar plate to determine the numbers of colony forming units (CFU). In first sampling (S1), only one canal of conventional method among the all experimental groups was positive cultured. In second sampling (S2), group showed the least positive culture numbers of E. faecalis. There was statistically significant difference between the and conventional needle irrigation methods in the mean value of Log CFU. According to the results of this study, showed better efficacy than conventional needle irrigation method in the elimination of E. faecalis from the root canal.

In vitro comparison of the effectiveness of chlorhexidine and two calcium hydroxide formulations on enterococcus faecalis.

The aim of this in vitro study was to compare the effectiveness of three intracanal medicaments in disinfecting the root canal and dentin of experimentally infected human teeth with Enterococcus faecalis (EF). One hundred extracted human single-rooted teeth were used. After root canal preparation, teeth were mounted in epoxy resin. Following sterilization, the teeth were infected for 28 days with EF. Then root canals were filled with one of three different disinfectants: viscous 2% Chlorhexidine (CHX), calcium hydroxide paste (CH) or a mixture of CH and CHX (n=30 in each group). Antimicrobial assessments were performed at 1, 3 and 7 days (n=10 in each time period). Microbial samples were obtained from root canals before and after the experiment. Also dentin samples were examined. The data was analyzed using Two- Way ANOVA test. The findings showed that there was no difference between experimental groups at different time periods. The mixture of CH/CHX in 7 days was able to eliminate EF completely from root canal system. The most elimination of EF was from dentinal tubules. According to the results of this in vitro study, viscous 2% CHX, mixture of CH with distilled water and 2% CHX are all effective disinfectants.

In vitro evaluation of the effectiveness of the chemomechanical preparation against Enterococcus faecalis after single- or multiple-visit root canal treatment

The purpose was to assess the elimination of Enterococcus faecalis in vitro in human mandibular premolars after chemomechanical preparation with or without the use of a calcium hydroxide dressing. After 60 days of contamination with E. faecalis, the root canals were prepared using the Crown-Down technique combined with 2% chlorhexidine gel irrigation. Then, the specimens were divided into two experimental groups, treated in a single visit or in multiple visits, and two control groups. The multiple-visit group received a dressing with calcium hydroxide for 14 days (Calen) and the single-visit group did not receive any medication. In the two control groups, the canals were filled with BHI after chemomechanical preparation with 2% chlorhexidine gel or distilled water. Microbial samples were taken from the root canals for colony forming unit count for each phase of the treatment using sterile paper points inside the root canal lumen. Data were ranked and analyzed by the Kruskal-Wallis statistical test. The residual microbial colonies were then assessed. The results showed that chemomechanical preparation using 2% chlorhexidine gel with no intra-canal dressing reduced by 100% the E. faecalis contamination of the root canal lumen. The calcium-hydroxide group that received the 14-day intra-canal dressing allowed a small number of bacteria to grow between visits, but without statistical differences between groups.

The Effectiveness of Three Instrumentation Techniques on the Elimination of Entererococcus Faecalis from a Root Canal: An In Vitro Study

The in vitro reduction of a bacterial population in a root canal by mechanical instrumentation using three techniques was evaluated. Root canals inoculated with a Enterococcus faecalis (E. faecalis) suspension were instrumented using hand Hedstroem files, Giromatic files, and Hero 642 rotary instruments. Irrigation was performed using sterile saline solution. Root canals were sampled before and after instrumentation. After serial dilutions, samples were plated onto Mitis-Salivarius agar and the colony forming units grown were counted. All instruments tested were able to significantly reduce the number of bacterial cells in the root canal, however, the results of this study indicated that Hedstroem files, Giromatic, and Hero 642 techniques were not significantly different in their ability to reduce intracanal bacteria.