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The aim of this study is to determine the cytotoxic effects of tetrasodium ethylenediaminetetraacetic acid (EDTANa 4 ) when used alone or when combined with sodium hypochlorite (NaOCl), with and without the addition of cetrimide (CTR). Human pulmonary fibroblast cell line was exposed to the following irrigating solutions: group 1, 2.5% NaOCl; group 2, 10% EDTANa 4 ; group 3, 20% EDTANa 4 ; group 4, 2.5% NaOCl/5% EDTANa 4 ; group 5, 2.5% NaOCl/10% EDTANa 4 ; group 6, 2.5% NaOCl/5% EDTANa 4 /0.2% CTR; group 7, 2.5% NaOCl/10% EDTANa 4 /0.2% CTR; group 8, control, cells in Dulbecco's modified Eagle's medium. Methyl thiazol tetrazolium assay was used to determine the viability of cells after 1 and 24 h. Viability percentages were analyzed for global comparison using the Welch test followed by the Games-Howell test to determine groups with similar viability, and the Student's t test was used to compare the two times. The lowest viability was obtained with a 2.5% NaOCl solution at both time periods. The association of NaOCl with EDTANa 4 increased the cellular viability in direct relation with the concentration of the chelating agent. Globally, after 24 h of exposure, cell viability reduced. The solutions of EDTANa 4 showed moderate cytotoxic effects when compared with NaOCl alone.

Introduction: The use of root canal filling materials with antibacterial activity can be considered beneficial to reduce the remaining microorganisms in the root canal system, where Enterococcus faecalis is often found, and prevent recurrent infection. The aim of this study was to evaluate the antimicrobial activity and capacity for inhibiting E. faecalis biofilm formation of AH Plus, alone and mixed with chlorhexidine (CHX), cetrimide (CTR), and combinations of the two., Methods: AH Plus alone and mixed with 1% and 2% CHX, 0.1%-0.5% CTR, and combinations of both were tested to assess antimicrobial activity by a modified direct contact test and determine inhibition of E. faecalis biofilm formation at 24 hours. The results were expressed as log10 viable counts. Eradication and inhibition of biofilm formation were understood as no bacterial growth or log10 reduction = 5 with respect to the control (AH Plus alone)., Results: AH Plus + CHX showed a low antimicrobial activity with respect to the control (at 2%, log10 reduction = 1.30). None of the tested concentrations achieved eradication or inhibition of biofilm. AH Plus + CTR showed a direct relationship of concentration-antimicrobial effect, reaching a log10 reduction of 2.92 at 0.5% and inhibition of biofilm formation at 0.2%. With the combination CHX + CTR, lower concentrations were needed for the same effect, and eradication and inhibition of biofilm were achieved., Conclusions: The addition of CHX, CTR, or some combination of both to AH Plus confers it with bactericidal and anti-biofilm activity against E. faecalis., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The use of root canal filling materials with antibacterial activity could be considered beneficial to reduce any remaining microorganisms and prevent recurrent infection. The aim of this study was to evaluate the physical properties of AH Plus (Dentsply DeTrey, Konstanz, Germany) alone and mixed with 1% or 2% chlorhexidine (CHX); 0.1%, 0.2%, 0.3%, and 0.5% of cetrimide (CTR); and combinations of both., Methods: Setting time, flow, solubility, and radiopacity of AH Plus and modified AH Plus were evaluated following the American National Standards Institute/American Dental Association's requirements (ANSI/ADA Specification No. 57/2000). Five samples of each material were tested for each property. The hypothesis of equality among groups was rejected by an analysis of variance test, and then a post hoc Tukey test was performed., Results: AH Plus and modified AH Plus gave values that are within the required standards. Overall, results indicate that CTR increased setting time, but CHX alone and CHX + CTR reduced it. CHX increased the flow, whereas CTR reduced it, and their combinations gave intermediate values comparable with those of AH Plus. Concerning solubility, the weight loss in all samples was under the 3% limit set by the ANSI/ADA. In comparison with AH Plus alone, radiopacity gave slightly lower values with CHX, higher values with CTR, and similar values with combinations., Conclusions: The addition of CHX, CTR, and combinations of both to AH Plus did not alter the physical properties specified by ANSI/ADA requirements., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The use of irrigating solutions with long-lived activity helps to avoid failure of endodontic therapy. The aim of the present study was to evaluate and compare the antimicrobial substantivity against Enterococcus faecalis by using as carrier a dentin-volumetric unit exposed to chlorhexidine (CHX) and alexidine (ALX)., Methods: Standardized dentin blocks of human molars were treated for 1 minute with 0.5% CHX, 2% CHX, 1% ALX, and 2% ALX. They were exposed to E. faecalis in suspension to determine antimicrobial substantivity during a period of 80 days. Results were analyzed by means of Kaplan-Meier survival analysis (P < .05)., Results: ALX obtained the best results, with differences that were significantly different from CHX regardless of the concentration. Although all the samples treated with CHX were contaminated at the end of the study period, a direct relationship was seen between concentration and survival time. There was no statistically significant difference between 2% and 1% ALX., Conclusions: The present study shows that 2% and 1% ALX used for 1 minute provide longer antimicrobial substantivity against E. faecalis than CHX when applied to 2% and 0.5%., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

The purpose of this study was to assess the efficacy of alexidine (ALX), alone and combined with N-acetylcysteine (NAC), in eradicating two Enterococcus faecalis strain biofilms. The biofilms of E. faecalis ATCC 29212 and the clinical isolate E. faecalis D1 were grown in the MBEC-high-throughput device for 24 h and were exposed to five twofold dilutions of ALX (2%-0.007 8%) alone and combined with 100 mg⋅mL(-1) NAC, for 1 and 5 min. Eradication was defined as 100% kill of biofilm bacteria. The Student's t-test was used to compare the efficacy of the associations of the two irrigants. After 1-min contact time, ALX eradicated the biofilms at all concentrations except for 0.007 8% and 0.015 6%-0.007 8% with E. faecalis ATCC 29212 and E. faecalis D1, respectively. Similar results for eradication and concentration were obtained when it was combined with 100 mg⋅mL(-1) NAC. After 5 min of contact time, ALX alone and combined with NAC eradicated all enterococci biofilms. ALX showed antimicrobial properties against the two E. faecalis strain biofilms tested at very low concentrations, and its combined use with NAC was not seen to enhance its activity.

Objective: To assess the influence of final irrigation protocols with chlorhexidine in the coronal leakage of Enterococcus faecalis in filled root canals., Material and Methods: Seventy single-root canals from extracted teeth were prepared using ProTaper instruments. The irrigation protocol accomplished an alternating irrigation with 5 mL of 2.5% sodium hypochlorite (NaOCI) and 17% EDTA between each file. The teeth were randomly divided into four experimental groups (n=15) according to the final irrigation regimen: group 1, without final irrigation; group 2, irrigation with 10 mL 2.0% chlorhexidine (CHX); group 3, with a final application of EC40™; and group 4, irrigation with the combination (1:1) of 0.2% CHX + 0.1% cetrimide (CTR). All the teeth were mounted in a two-chamber apparatus and the coronal access was exposed to E. faecalis. The presence of turbidity in the BHI broth over a period of 180 days was observed. The Friedman test was used for statistical analysis., Results: EC40™ varnish showed the least leakage at 180 days, and was statistically similar to 2% CHX. No significant differences were observed between the group without final irrigation and the 2% CHX group or 0.2% CHX + 0.1% CTR., Conclusions: In this ex vivo study, EC40™ showed the longest delayed coronal leakage of E. faecalis, although without significant differences from 2% CHX.

Objective: The aim of this study was to determine the decalcifying efficacy of 7% maleic acid (MA), 2% chlorhexidine (CHX), and combinations of 7% MA + 0.2% cetrimide (CTR) and 2% CHX + 0.2% CTR, in four time periods., Study Design: Four specimens per tooth were obtained from a 2-mm thick slice of the cervical third of the root of ten human incisors. At 1, 2, 3 and 5 minutes of immersion, the concentrations of Ca2+ were measured by atomic absorption spectrophotometry. The results were analyzed using the Mann-Whitney U-test., Results: Statistically significant differences were seen for the extracted calcium in all time periods. The amount of calcium extracted by 7% MA was the highest at all four immersion times, followed by 7% MA + 0.2% CTR. Two percent CHX and its combination with 0.2% CTR extracted virtually no calcium., Conclusions: The decalcifying capacity of 7% MA and 2% CHX diminished when combined with 0.2% CTR.

Objective: The antimicrobial activity of lactic acid (LA) alone or in combination with chlorhexidine (CHX) and cetrimide (CTR) against three Enterococcus faecalis strains, E. faecalis ATCC 29212, E. faecalis EF-D1 and E. faecalis U-1765, one Enterococcus durans strain and one dual-species biofilm was investigated., Study Design: The irrigating solutions tested were 20%, 15%, 10%, 5% and 2.5% LA, alone and in combination with 2% CHX and with 0.2% CTR. The biofilms were grown in the MBECTM high-throughput device for 24 hours and exposed to the solutions for 30 seconds and 1 minute. "Eradication" was defined as 100% bacterial kill., Results: Twenty percent LA eradicated all enterococci biofilms after 30 seconds contact time. The association of LA+0.2% CTR achieved better results than LA alone, in contrast with the results obtained using LA+2% CHX. E. durans was eradicated by all the tested solutions at 1 minute. The dual-species biofilm, E. faecalis ATCC 29212+E. durans, gave intermediate values of the pure cultures., Conclusions: LA is capable of eradicating enterococci biofilm at a concentration of 20%. The combination of lower concentrations with 0.2% CTR achieved eradication after 1 minute.

Introduction: The use of chelating agents in endodontic treatment is required to remove the smear layer and to achieve better disinfection within the root canal system. The aim of this study was to evaluate the residual antimicrobial activity of 17% ethylenediaminetetraacetic acid (EDTA), 7% maleic acid (MA), and 10% lactic acid (LA) alone and combined with 0.2% cetrimide (CTR) on infected root canals with Enterococcus faecalis., Methods: Biofilms of E. faecalis were grown in uniradicular roots for 4 weeks. After preparation the roots were randomly divided into 6 groups (n = 15) according to the final irrigation regimen as follows: 5 mL of 17% EDTA; 5 mL of 17% EDTA + 0.2% CTR; 5 mL of 7% MA; 5 mL of 7% MA + 0.2% CTR; 5 mL of 10% LA; and 5 mL of 10% LA + 0.2% CTR. Samples were collected for 60 days to denote the presence of bacterial growth. Fisher and Pearson χ(2) tests were applied to compare the percentages of specimens without E. faecalis regrowth at all the time periods., Results: There were significant differences in bacterial regrowth between the groups with and without CTR. There were not significant differences over time among the 3 groups with CTR or among the 3 without CTR., Conclusions: The residual activity against E. faecalis of 7% MA + 0.2% CTR, 17% EDTA + 0.2% CTR, and 10% LA + 0.2% CTR was greater than the use of chelating agents alone., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The application of a final irrigating solution that remains active over a fairly long period of time stands as one strategy for preventing bacterial recolonization or eliminating the bacteria that persist after root canal treatment. The aim of this study was to evaluate the residual antimicrobial activity of four final irrigation regimens in root canals contaminated with Enterococcus faecalis., Methods: Biofilms of E. faecalis were grown in uniradicular roots for 4 weeks. After preparing the roots chemomechanically, four final irrigation regimens were applied: (1) group EDTA-NaOCl, 17% EDTA followed by 5.25% sodium hypochlorite (NaOCl); (2) group MA-NaOCl, 7% maleic acid (MA) followed by 5.25% NaOCl; (3) group EDTA-CHX + CTR, 17% EDTA followed by 2% chlorhexidine (CHX) + 0.2% cetrimide (CTR); and (4) group MA-CHX + CTR, 7% MA followed by 2% CHX + 0.2% CTR. Samples were collected for 60 days to denote the presence of bacterial growth. The Fisher exact test was used to compare the percentages of specimens without E. faecalis regrowth., Results: All root canals in which the final irrigant was 5.25% NaOCl yielded positive cultures on the fifth day. Groups EDTA-CHX + CTR and MA-CHX + CTR with a final irrigation of 2% CHX + 0.2% CTR showed respective percentages of samples without regrowth of 72.1% and 66.8% at 60 days. There were no statistically significant differences between these groups., Conclusions: The combination of 2% CHX + 0.2% CTR would be an effective alternative final irrigation regimen given its antimicrobial action over time., (Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Chelating agents, such as EDTA or citric acid, can be incorporated into irrigants in order to provide different properties in a single compound. Maleic acid has recently been proposed as an alternative irrigant to EDTA given its better smear layer removal and biocompatibility; however, its antimicrobial activity is not known. The purpose of the present study was therefore to evaluate the in vitro capacity of maleic acid in eradicating Enterococcus faecalis biofilms and to evaluate the combinations of cetrimide with maleic acid, citric acid, and EDTA., Methods: E. faecalis biofilms were grown in the MBEC high-throughput device (Innovotech; Edmonton, Alberta, Canada) for 24 hours and exposed to the irrigating solutions for 30 seconds and 1 and 2 minutes. "Eradication" was defined as 100% bacterial kill. The Student t test was used to compare the efficacy of the irrigant combinations., Results: Maleic acid eradicated E. faecalis biofilms at a concentration of 0.88% after 30 seconds and at 0.11% after 2 minutes of contact time. When combined with 0.2% cetrimide, it eradicated the biofilms at all three times of exposure. The combination of 0.2% cetrimide with either 15% EDTA or 15% citric acid gave 100% bacterial kill after one minute of contact with the biofilms., Conclusions: Maleic acid showed antimicrobial activity against E. faecalis biofilm both alone or in association with cetrimide from 30 seconds onward and the combination of EDTA and citric acid with cetrimide eradicated biofilm after 1 minute of contact., (Copyright © 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Enterococcus faecalis is the most commonly isolated bacteria from root canals of teeth with persistent periapical periodontitis. Its ability to grow as a biofilm impedes the elimination of E. faecalis by using irrigating solutions. The purpose of this study was to assess the efficacy of cetrimide and chlorhexidine (CHX), alone and in association, in combined and alternating form, in eradicating biofilms of E. faecalis., Methods: Biofilms grown in the MBEC-high-throughput device for 24 hours were exposed to irrigating solutions for 30 seconds and 1 and 2 minutes. Eradication was defined as 100% kill of biofilm bacteria. The Student t test was used to compare the efficacy of the associations of the 2 irrigants., Results: Cetrimide eradicated E. faecalis biofilms at concentrations of 0.5%, 0.0312%, and 0.0078% at 30 seconds and 1 and 2 minutes of contact time, respectively. CHX did not eradicate the biofilms at any of the concentrations (4% initial concentration) or times assayed. The association of 0.1% and 0.05% cetrimide with any concentration of CHX, whether in combined or alternating application, effectively eradicated E. faecalis biofilms at all the contact times tested. Eradication was also achieved with 0.02% and 0.01% cetrimide at 2 minutes. Statistical analysis revealed significantly better results with alternating rather than combined use of cetrimide and CHX (P < .05)., Conclusions: The associated use of cetrimide and CHX provided better results than their applications as single agents against E. faecalis biofilms, and the alternating application was significantly more effective than the combined mode of application.