Conventional Endodontic Irrigants Research Articles

A Comparative Evaluation of the Effect of Different Endodontic Irrigating Solutions on Microhardness of Root Canal Dentin: An in vitro Study.

During endodontic therapy, irrigation solutions applied in the root canal may affect the physicochemical properties of the dentinal wall, thereby changing its microhardness. This may adversely affect the sealing ability and adhesion of dental materials. Therefore, many studies have focused on the search for an ideal root canal irrigant that has a minimal effect on dentinal microhardness. This in vitro study was conducted to determine the changes in dentin microhardness after root canal irrigation with different endodontic irrigants. Ninety-five freshly extracted maxillary central incisor teeth with straight single canals were selected. These teeth were sectioned transversely at the level of the cementoenamel junction. The working length of each tooth was determined, and canal space was prepared by the HyFlex CM rotary file system. During instrumentation, normal saline was used for irrigation. Then, teeth were split longitudinally into two segments. According to the irrigating solution employed, samples were divided into five groups (n=19): normal saline (Group A), 3% sodium hypochlorite (Group B), 2% chlorhexidine (Group C), 5% calcium hypochlorite (Group D), and 0.2% nanochitosan (Group E).3 mL of the corresponding irrigating solution was administered for total15 minutes in each prepared sample. The Vickers micro-hardness tester was then used to assess micro-hardness. The data was analyzed using one-way analysis of variance (ANOVA). All tested irrigating solutions decreased the dentinal microhardness. Samples irrigated with 5% calcium hypochlorite demonstrated dentinal microhardness of 42.43±1.62, which is the lowest among all the tested groups, followed by nano chitosan, sodium hypochlorite, and chlorhexidine. Samples treated with control group (saline) demonstrated the maximum microhardness of dentin in the present study. Within the limitations of this research, it can be concluded that the tested novel irrigating solutions, 5% calcium hypochlorite and 0.2% nanochitosan, were more detrimental to radicular dentin microhardness when compared with conventional endodontic irrigants.

Effect of herbal irrigants on surface roughness of intraradicular dentin using quantitative method of 3D surface texture analysis

Replacing the conventional endodontic irrigants with herbal agents could avoid complications associated with using sodium hypochlorite (NaOCl). Endodontic irrigants alter the surface roughness of the dentinal wall surface, which affects sealer mechanical retention. This study aimed to assess the effect of experimental herbal Moringa oleifera and orange peel extract irrigant on intraradicular dentin (IRD) surface roughness using quantitative 3D surface analysis by scanning electron microscopy (SEM) regarding the smear layer assessment. Sixty human root sections were divided into four groups (n = 15): NaOCl combined with 17% ethylenediaminetetraacetic acid (EDTA); negative control (saline); moringa extract (MO); and orange oil (OO). SEM images were assessed quantitatively for surface roughness (Ra) in the coronal, middle, and apical IRD. The data were analysed by Kruskal–Wallis, Friedman, and Dunn’s tests. All groups showed statistically significant differences (P = 0.007). MO exhibited significantly greater Ra values at the coronal, middle, and apical root levels than OO (P = 0.007, 0.009, and 0.046, respectively). There was no significant change in Ra values at various root levels within each group at P = 0.091, 0.819, 0.819, and 0.549 for the EDTA, saline, MO, and OO groups. Considerable (IRD) surface roughness analysis makes Moringa extract a promising herbal endodontic irrigant alternative to the NaOCl plus EDTA regimen.

Scanning Electron Microscopy Analysis of Smear Layer Removal Ability of Conventional Endodontic Irrigation Regimen, MTAD, and QMix™ Versus a Mixture of Azadirachta indica and Citrus limon: An In Vitro Study.

Smear layer removal from root canals aid in the penetration of both irrigants and endodontic sealer into the dentinal tubules, thereby improving the efficacy of endodontic treatment. The aim of this in vitro study was to compare the smear layer removal ability of a conventional endodontic irrigation regimen, MTAD (mixture of tetracycline, acid, and detergent), and QMix™ (Dentsply Sirona, Charlotte, North Carolina, United States) with that of a mixture of herbal irrigants, namely, aqueous extracts of Azadirachta indica (neem) and Citrus limon (lemon), evaluated using scanning electron microscopy (SEM). We selected 40 extracted human premolar teeth for the study, which we randomly divided into five groups (eight samples each) according to irrigation solution: (i) Group A (normal saline); (ii) Group B (conventional endodontic regimen, 3% sodium hypochlorite (NaOCl) + 17% ethylenediamine tetraacetic acid (EDTA) + 2% chlorhexidine (CHX)); (iii) Group C (MTAD); (iv) Group D (QMix 2-in-1); and (v) Group E (aqueous extracts of Azadirachta indica and Citrus limon). After we prepared the canals with ProTaper Universal nickel-titanium (Ni-Ti) rotary files (Dentsply Sirona) and the respective irrigants, we split the teeth longitudinally to evaluate the amount of remnant smear layer in the coronal, middle, and apical thirds using SEM photomicrographs. We performed statistical analyses of the data using the Kruskal-Wallis and Mann-Whitney U tests, where the level of significance was set at 0.05. The SEM analysis of the coronal third showed mean valuesof 3.83 in Group A, 3.67in Group B, 2.79in Group C, 3.63in Group D, and 4.00in Group E. The SEM analysis of the middle third showed mean values of 4.00 in Group A, 3.88in Group B, 3.75 in Group C, 3.50in Group D,and 3.50 in Group E.The SEM analysis of the apical third showed mean values of 3.92 in Group A, 3.63in Group B, 3.71in Group C, 3.88 in Group D, and 3.17 in Group E.Therefore, we found that there were significant statistical differences between the groups when an overall comparison was done for the coronal, middle, and apical third, with a p-value of 0.001. On multiple comparisons across the different tooth-section thirds. Groups A and B showed statistically significant differences in the apical third (p-value=0.017). Groups A and C showed statistically significant differences in the coronal third and middle third (p-values=0.001 and 0.010, respectively). Groups A and D showed statistically significant differences in the middle third (p-value=0.001). Groups A and E showed statistically significant differences in all thirds (p-values=0.039, 0.001, and 0.001, respectively) Conclusion: The conventional needle irrigation with MTAD showed the highest level of smear layer removal ability on the root canal surface, followed by QMix 2-in-1, the Azadirachta indica leaf and Citrus limon extract mixture, and the conventional endodontic regimen. Normal saline showed the lowest smear layer removal effect.

A new model of in vitro dentin intratubular contamination for Fusobacterium nucleatum: Validation by confocal laser scanning microscopy

ObjectivesTo test and validate a new protocol for in vitro contamination of dentinal tubules using Fusobacterium nucleatum (F. nucleatum) by confocal laser scanning microscopy (CLSM), in addition to evaluating the effectiveness of conventional endodontic irrigants such as sodium hypochlorite (NaOCl) and chlorhexidine (CLX) on this biofilm. Material and methodsThirty lower premolars were contaminated with F. nucleatum (ATCC 51190) for 7 days under anaerobic conditions using the proposed new model. The specimens were divided into a control group and experimental groups, according to the irrigants: NaOCl 2.5% and CLX 2%. Then, the samples were submitted for analysis by CLSM and the LIVE/DEAD technique to quantify bacterial viability. Data normality was verified by the Shapiro-Wilk test. Intragroup and intergroup comparisons were performed using the Kruskal-Wallis test, followed by Dunn's post-test. ResultsThe CLSM images obtained demonstrated the effectiveness of the proposed new contamination protocol, with a high percentage of viable bacteria in relation to the treated groups (p < 0.05). Lower viability values were observed for the 2.5% NaOCl group. ConclusionThe new contamination protocol resulted in a high and homogeneous percentage of viable bacteria in the dentinal tubules in all specimens evaluated. Both irrigating solutions proved to be effective in reducing the intratubular microbiota, especially 2.5% NaOCl.

Comparative evaluation of antifungal efficacy of conventional endodontic irrigants and chitosan nanoparticles.

The purpose of this study was to evaluate the efficacy of 3% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and chitosan nanoparticles against Candida albicans using the agar disc-diffusion test. Strain of C. albicans was cultivated in Sabouraud Dextrose Agar. Chitosan nanoparticles were synthesized using an ionic gelation method. Four groups were made according to the irrigants used. Group 1: 3% NaOCl, Group 2: 2% CHX, Group 3: chitosan nanoparticles, and Group 4: saline as control. Discs were added with the different irrigants and placed in a dish containing C. albicans. The plates were incubated at 37°C for 24h. The zone of inhibition was measured in millimeter. Statistical analysis was performed using the test of one-way variance (ANOVA) and post hoc Tukey. Group 1 showed significantly higher zone of inhibition compared to Groups 2 and 3 (P < 0.05). There were no significant differences between the zones of inhibition of Groups 2 and 3 (P < 0.05). Chitosan nanoparticles and 2% CHX have similar efficacy against C. albicans, whereas 3% NaOCl was significantly better than both chitosan nanoparticles and CHX.

Influence of agitation methods of irrigants after methylene blue-mediated PDT on the bonding interface of a fiber post cementation system

BackgroundThis study evaluated the effects of final agitation methods of irrigants to remove methylene blue and sodium hypochlorite residues after PDT-assisted endodontic treatment on the bond strength of fiber posts cemented with etch-and-rinse adhesive and conventional resin cement. MethodsNinety bovine teeth were endodontically treated. In sequence, post space preparation followed by methylene blue-mediated PDT and sodium hypochlorite (NaOCl) irrigation were performed. Six final irrigations protocols for dye and NaOCl removal were performed prior to cementation with etch-and-rinse adhesive (Adper Scocthbond Multipurpose) and conventional dual resin cement (RelyX ARC): Conventional endodontic irrigation (CEI), passive ultrasonic irrigation (PUI), mechanical agitation with XP Endo Finisher (XPF), XP Clean (XPC) or Easy Clean (ECL) and distilled water (NCO - control). After fiber post cementation, push-out bond strength test was performed at different thirds of the post space. Failure mode was also analyzed. ANOVA and Tukey's post-hoc test was used for data analysis (α=5%). ResultsPUI, XPF e XPC protocols showed the highest bond strength values with no difference among them (p > 0.05), although they were similar to NCO, regardless of the post space third. CEI e ECL showed similar bond strength values, regardless of the third (p > 0.05). Adhesive failure was the most incident for CEI and ECL, while mixed and cohesive failures were predominant in PUI, XPF, XPC and NCO groups. ConclusionsMechanical agitation of distilled water with XPF, XPC and PUI after methylene blue-mediated PDT and irrigation with 2.5% sodium hypochlorite promoted bond strength of the resin cementation system in post space dentin comparable to control group.

Investigating the Antibacterial Effect of Passive Ultrasonic Irrigation, Photodynamic Therapy and Their Combination on Root Canal Disinfection.

Introduction: Enterococcus faecalis is a gram-positive, facultative anaerobic bacterium associated with persistent endodontic infections. Conventional disinfection methods may not completely eradicate the bacteria within the root canal system. Therefore, novel modalities have been suggested to optimize root canal disinfection. The aim of this study was to evaluate and compare the antibacterial effect of photodynamic therapy (PDT), passive ultrasonic irrigation (PUI) and their combination in addition to conventional endodontic irrigation against E. faecalis biofilms in root canals. Methods: Root canals of 50 single-rooted extracted human teeth were prepared and incubated with E. faecalis for 21 days. They were then divided into 4 treatment groups and a control group as follows: (1) NaOCl-Syringe irrigation with 2.5% NaOCl, (2) PUI-Passive ultrasonic irrigation with NaOCl, (3) NaOCl+PDT-Photodynamic therapy following syringe irrigation with NaOCl, (4) PUI+PDT, (5) Control-Syringe irrigation with saline. Colony-forming units were counted and bacterial reduction was calculated for each treatment group. Results: All treatments led to significant reductions in the bacterial load compared to the control group. PUI and PUI+PDT led to the complete elimination of the bacteria from the root canals. NaOCl and NaOCl+PDT treatments reduced the bacteria by 99.9% and 99.5% respectively. NaOCl+PDT was significantly less effective in reducing the bacteria compared to other treatment groups. There were no significant differences between the NaOCl, PUI, and PUI+PDT groups. Conclusion: Passive ultrasonic irrigation with or without the combination of Photodynamic therapy completely eradicated the bacteria. The use of PDT as an adjunction to NaOCl syringe irrigation and PUI did not enhance their antibacterial effect.

A randomized clinical trial of antimicrobial efficacy of photoactivated disinfection, conventional endodontic irrigation and their combination in primary endodontic infections

Aim: The aim of this study is to evaluate and compare the antimicrobial efficacy of photoactivated disinfection (PAD), conventional irrigation (CEI), and combination of both against primary endodontic infections in vivo. Methods: Active controlled and parallel design trial was registered with Clinical Trials Registry India under reference no. CTRI/2018/08/015478. Forty-eight qualified patients were randomly divided into three groups (n = 16 each) using the lottery method, Group-I: CEI, Group-II: PAD, Group-III: CEI and PAD. Access opening and working length were determined, and preinstrumentation sample (S1) was taken by inserting sterile paper point into the canal. Postinstrumentation sample (S2) was collected following biomechanical preparation and irrigation with respective interventions. Microbiological samples (S1, S2) were plated on brain heart infusion agar. Colony-forming units were counted using the classic bacterial counting method, and percentage bacterial reduction was determined. Statistical Analysis: Inter- and intra-group comparison was made using repeated measures of ANOVA. Post hoc Tukey analysis was done for pairwise comparison with P Results: In the intragroup comparison, statistically significant reduction was seen at S2 among all experimental groups. However, in intergroup comparison, mean bacterial reduction in Group III was significantly lower than the other groups. This difference was statistically significantly better between Group I and Group III; Group II, and Group III. However, no statistically significant difference was seen between Group I and Group II. Within the limitations of this study, it can be concluded that a combination of CEI and PAD showed significantly better antimicrobial activity against primary endodontic infections and can be recommended as an adjunct to facilitate maximum root canal disinfection.

Comparative evaluation of substantivity of two biguanides - 0.2% polyhexanide and 2% chlorhexidine on human dentin.

Background:Substantivity is one of the desirable characteristics of root canal irrigants. Among conventional endodontic irrigants, only chlorhexidine (CHX) is known to exert significant substantivity on root canal dentin. This study explored the substantivity activity of a polymeric biguanide-poly hexamethylene biguanide (PHMB).Aim:The aim of this study was to determine the substantivity of a polymeric biguanide - 0.2% PHMB and compare it with that of 2% CHX.Materials and Methods:To evaluate and compare the substantivity of 0.2% PHMB and 2% CHX on root canal dentin, dentin disks were prepared and substantivity after 1 h, 24 h, 7 days and 21 days was measured using spectrophotometry.Statistical Analysis Used:The data so obtained were analyzed, and the intergroup comparison was made using unpaired t-test.Results:The results of this study indicated that 0.2%. PHMB exerts significantly greater substantivity than 2% CHX on human dentin.Conclusion:Within the limitations, this study supports the use of 0.2% polyhexanide as an endodontic irrigant based on its property of substantivity.

Effectiveness of nanoparticles solutions and conventional endodontic irrigants against Enterococcus faecalis biofilm.

To overcome the challenge imposed by the presence of biofilm and reach significant bacterial reduction of the root canals, many irrigants have been indicated during endodontic treatment, among them nanoparticles solutions. This study aims to evaluate the effectiveness of experimental solutions containing silver and zinc oxide nanoparticles (ZnO Np) and conventional endodontic irrigants against Enterococcus faecalis biofilm, in root canals. Seventy-six extracted human teeth were biomechanically prepared and sterilized. The root canal surface was exposed to E. faecalis suspension to form a 7-day-old biofilm. Four teeth were analyzed by scanning electron microscopy (SEM) to confirm the presence of biofilm. The remaining teeth were randomly divided into 6 groups (n = 12) and treated with passive ultrasonic irrigation and different solutions: G1 - 0.85% saline (control); G2 - 2% chlorhexidine gluconate (CHX); G3 - 5% sodium hypochlorite (NaOCl); G4 - 1% NaOCl; G5 - 1% silver nanoparticles (Ag Np) solution; and G6 - 26% ZnO Np solution. The susceptibility of E. faecalis biofilms to disinfecting solutions (n = 10) was determined by quantification of colony-forming units. SEM analysis was also carried out to examine the biofilm structure after treatments (n = 2). Data were analyzed by Kruskal-Wallis and Dunn post hoc tests (P < 0.05). All tested solutions showed superior effectiveness compared to 0.85% saline (P < 0.05). Overall, 2% CHX presented the most effective action against E. faecalis biofilm, followed by 5% NaOCl, 1% Ag Np, 26% ZnO Np, and 1% NaOCl. 1% Ag Np and 26% ZnO Np were effective against E. faecalis biofilm similarly to conventional endodontic irrigants.

Comparative analysis of smear layer removal by conventional endodontic irrigants with a newly experimented irrigant-fumaric acid: A scanning electron microscopic study.

Introduction:This study was aimed to evaluate the efficacy of 17% ethylenediaminetetraacetate (EDTA), 7% maleic acid and 0.7% fumaric acid in smear layer removal from the root canal walls.Materials and Methods:Forty single-rooted mandibular premolars were collected and prepared till F3 rotary ProTaper file with 1 ml of 3% of sodium hypochlorite after each instrument change. Samples were randomly divided into 4 groups according to the final irrigating solution: 17% EDTA, 7% maleic acid, 0.7% fumaric acid, and 0.9% saline. The samples were prepared for scanning electron microscope analysis to observe smear layer removal at coronal, middle, and apical third level of root canal system.Results:At coronal third level, fumaric acid was equally efficient in smear layer removal when compared to maleic acid and EDTA without any significant difference between them. At the middle third, fumaric acid showed significantly better results than maleic acid followed by EDTA. At the apical third, both fumaric acid and maleic acid were equally effective without any significant difference between them but both showed significantly better results than EDTA.Conclusion:Fumaric acid can be tried as a new irrigating agent for smear layer removal in root canal system.

Antibacterial effect of chlorhexidine-cetrimide combination, Salvia officinalis plant extract and octenidine in comparison with conventional endodontic irrigants.

The aim of the present study was to compare the antimicrobial effect of sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), a CHX/cetrimide solution (CHX+CTR), octenidine hydrochloride (OCT) and Salvia officinalis plant extract against Enterococcus faecalis. Seventy decoronated single-rooted human teeth were infected and divided into 6 test (n=10) and 2 control groups (n=5) (negative, sterile samples and positive, infected samples). Following irrigants were then applied to test groups: 2.5% NaOCl, 5.25% NaOCl, CHX, CHX+CTR, S. officinalis extract and OCT. The dentin chips were obtained from inner root canal walls and analyzed by counting the number of colony forming units (CFU). The 2.5% NaOCl, 5.25% NaOCl, CHX and OCT groups presented no bacterial growth (CFU=0). S. officinalis and CHX+CTR groups reduced the number of E. faecalis cells but could not eliminate all. OCT may have potential as an endodontic irrigant in treatment of infected root canals.

Influence of QMix irrigant on the micropush-out bond strength of biodentine and white mineral trioxide aggregate.

To evaluate the effect of QMix and other conventional endodontic irrigants on the micropush-out bond strength of Biodentine (BD) and white mineral trioxide aggregate (WMTA). One hundred eighty midroot dentin slices with a thickness of 1.0 mm were prepared. BD and WMTA were placed inside the lumens of the root slices (n = 90). Then the specimens of each material were divided into 6 groups (n = 15) according to irrigation solution (saline, 5.25% NaOCl, 2% CHX, 17% EDTA, or QMix) immersed in the same for 30 min. For the control group, a wet cotton pellet was placed over the specimen. After that, the micropush-out bond strength was determined using a universal testing machine, and the bond failure mode was determined using a stereomicroscope. The morphological microstructures of specimens were evaluated with scanning electron microscopy (SEM). Data were analyzed using ANOVA and Tukey's post-hoc test. BD revealed higher bond strength than WMTA (p < 0.05). WMTA was significantly affected after exposure to 2% CHX solution. QMix irrigant did not compromise the bond strength of BD or WMTA. Most failures for BD were cohesive, while for WMTA, adhesive failures were the predominant type. A substantial change in the microstructure of BD and WMTA occurred after exposure to different irrigation solutions. QMix did not affect the bond strength of BD or WMTA. BD showed higher resistance than WMTA to dislodgement forces from root dentin.

The antimicrobial effect of new and conventional endodontic irrigants on intra-orally infected dentin

Objectives. To evaluate if the incorporation of antimicrobial compounds to chelating agents or the use of chelating agents with antimicrobial activity as 7% maleic acid and peracetic acid show similar disinfection ability in comparison to conventional irrigants as sodium hypochlorite or iodine potassium iodide against biofilms developed on dentin. Materials and methods. The total bio-volume of live cells, the ratio of live cells and the substratum coverage of dentin infected intra-orally and treated with the irrigant solutions: MTAD, Qmix, Smear Clear, 7% maleic acid, 2% iodine potassium iodide, 4% peracetic acid, 2.5% and 5.25% sodium hypochlorite was measured by using confocal microscopy and the live/dead technique. Five samples were used for each irrigant solution. Results. Several endodontic irrigants containing antimicrobials as clorhexidine (Qmix), cetrimide (Smear Clear), maleic acid, iodine compounds or antibiotics (MTAD) lacked an effective antibiofilm activity when the dentin was infected intra-orally. The irrigant solutions 4% peracetic acid and 2.5–5.25% sodium hypochlorite decrease significantly the number of live bacteria in biofilms, providing also cleaner dentin surfaces (p < 0.05). Conclusions. Several chelating agents containing antimicrobials could not remove nor kill significantly biofilms developed on intra-orally infected dentin, with the exception of sodium hypochlorite and 4% peracetic acid. Dissolution ability is mandatory for an appropriate eradication of biofilms attached to dentin.

In Vivo Efficacy of Three Different Endodontic Irrigation Systems for Irrigant Delivery to Working Length of Mesial Canals of Mandibular Molars

IntroductionMany in vitro studies have debated over the ability of different irrigant delivery and/or agitation systems to reach the apical third of curved root canals; however, little is known about irrigant penetration in vivo. Therefore, the purpose of this study was to compare the efficacy of the conventional endodontic irrigation needle, passive ultrasonic irrigation (PUI), and a negative pressure system for irrigant delivery to working length (WL) of mesial canals of mandibular molars. MethodsThirty mesial canals of 30 vital mandibular first or second molars were randomly assigned into 3 groups (n = 10): (1) Monoject syringe with 27-gauge needle; (2) PUI with IrriSafe tip; and (3) EndoVac system. All canals were treated following the same preparation protocol to size 35/0.04 by using 5.25% NaOCl as irrigant during preparation procedure. Before obturation, canals were irrigated with 1 mL of a radiopaque solution by using the assigned irrigation system, and a digital radiograph was taken by using a parallel technique. With the aid of image editing software the distance between WL and maximum irrigant penetration was measured. ResultsMean distances for Monoject, PUI, and EndoVac groups were 1.51 mm, 0.21 mm, and 0.42 mm, respectively. Analysis of variance test showed statistically significant differences between groups (P < .001). Tukey honestly significant difference test showed statistically significant differences between the Monoject group and the other 2 groups (P < .001) but no significant differences between PUI and EndoVac groups (P = .06). ConclusionsPUI and EndoVac are more effective than the conventional endodontic needle in delivering irrigant to WL of root canals.

Antibacterial effectiveness of peracetic acid and conventional endodontic irrigants

This study evaluated the in vitro antibacterial activity of conventional and experimental endodontic irrigants against Enterococcus faecalis. The following substances were evaluated by direct contact test: 2.5% sodium hypochlorite (NaOCl); 2% chlorhexidine (CHX); 1% peracetic acid. After different contact periods (30 s, 1, 3, and 10 min), a neutralizing agent was applied. Serial 10-fold dilutions were prepared and plated onto tryptic soy agar (TSA) and the number of colony-forming units per milliliter (CFU/mL) was determined. Sterile saline was used as a negative control. Both 2.5% NaOCl and 2% CHX eliminated E. faecalis after 30 s of contact. Peracetic acid reduced the bacterial counts by 86% after 3 min and completely eliminated E. faecalis after 10 min. These results allow us to conclude that 1% peracetic acid is effective against E. faecalis, despite its slower action compared with 2.5% NaOCl and 2% CHX.

Scanning electron microscope study of a new irrigation method in endodontic treatment

The effectiveness of a newly developed perforated endodontic irrigation needle, with its distal aperture sealed, was compared to conventional endodontic irrigation procedures. In all instances 5 percent sodium hypochlorite was used since the delivery system, rather than the irrigant, was being evaluated. A base line group in which all soft tissue was described was also included. The results indicate that the perforated endodontic irrigation needle is a very effective instrument for the cleansing of instrumented root canals.