Comparação da propriedade antimicrobiana da clorexidina e do hipoclorito de sódio como irrigantes endodônticos: revisão integrativa / Comparison between the antimicrobial properties of chlorhexidine and sodium hypochlorite as endodontic irrigants: an integrative review / Comparación de la propiedad antimicrobiana de la clorhexidina y el hipoclorito de sodio como irrigantes endodónticos: revisión integradora

Introdução:Durante o tratamento endodôntico, devido às complexidades anatômicas dos canais radiculares, a ação mecânica dos instrumentos não é suficiente para a completa desinfecção dos condutos. Dessa forma, se faz necessário o uso de soluções irrigadoras que possampotencializar a desinfecção do sistema de canais radiculares. Objetivo:Realizar uma revisão integrativa da literatura para comparar as propriedades antimicrobianas da clorexidina com o hipoclorito de sódio.Metodologia:A busca na literatura foi realizada no período de setembro de 2019 a agosto de 2021, nas seguintes bases de dados: PUBMED/MEDLINE, LILACS e SCIELO. Utilizando os descritores: clorexidina, hipoclorito de sódio, irrigante do canal radicular e limpeza. Utilizou-se como critérios de busca, trabalhos experimentais laboratoriais in vitro, publicados entre os anos de 2017 e 2021.Resultados:Foram encontrados 165 artigos, dos quais 15 foram selecionados ao final do processo. 8 trabalhos não encontraram diferença estatisticamente significativa entre a clorexidina e o hipoclorito,5 artigos apresentaram resultados superiores dohipoclorito de sódioem 2 a clorexidina foi superior. Conclusões:Após análise da literatura, observamos semelhança entre a ação antimicrobiana do hipoclorito de sódioe da clorexidina, e podemos concluir que ambas apresentam boa ação antimicrobiana, justificando seu uso clinicamente (AU).

Introduction:During endodontic treatment, due to the anatomical complexities of the root canals, the mechanical action of the instruments is not sufficient for the complete disinfection of the canals. Thus, it is necessary to use irrigating solutions that can makethe disinfection of the root canal system.Objective:Conduct an integrative literature review to compare the antimicrobial properties of chlorhexidine with sodium hypochlorite.Methodology:The literature search was carried out from September 2019 to August 2021, in the following databases: PUBMED/MEDLINE, LILACS and SCIELO. Using the descriptors: chlorhexidine, sodium hypochlorite, root canal irrigant and cleaning. As search criteria, in vitro laboratory experimental works published between 2017 and 2021 were used.Results:A total of 165 articles were found, of which 15 were selected at the end of the process. 8 studies did not find a statistically significant difference between chlorhexidine and hypochlorite, 5 articles showed superior results for NaOCl and in 2 chlorhexidine was superior.Conclusions:After analyzing the literature, we observed a similarity between the antimicrobial action of sodium hypochlorite and chlorhexidine, and we can conclude that both have good antimicrobial action, justifying their clinical use (AU).

Introducción:Durante el tratamiento endodóntico, debido a las complexidades anatómicas de los conductos radiculares, la acción mecánica de los instrumentos no es suficiente para la desinfección completa de los conductos. Por lo tanto, es necesario utilizar soluciones de irrigación que puedan mejorar la desinfección del sistema de conductos radiculares.Objetivo: Realice una revisión integradora de la literatura para comparar las propiedades antimicrobianas de la clorhexidina con el hipoclorito de sodio.Metodología: La búsqueda bibliográfica se realizó desde septiembre de 2019 hasta agosto de 2021, en las siguientes bases de datos: PUBMED/MEDLINE, LILACS y SCIELO. Usando los descriptores: chlorhexidine, sodium hypochlorite, root canal irrigant and cleaning. Como criterio de búsqueda se utilizaron trabajos experimentales de laboratorio in vitro publicados entre 2017 y 2021.Resultados: Se encontraron un total de 165 artículos, de los cuales 15 fueron seleccionados al final del proceso. 8 estudios no encontraron diferencia estadísticamente significativa entre clorhexidinae hipoclorito, 5 artículos mostraron resultados superiores para NaOCl y en 2 la clorhexidina fue superior.Conclusiones: Después de analizar la literatura, observamos una similitud entre la acción antimicrobiana del hipoclorito de sodio y la clorhexidina,y podemos concluir que ambos tienen una buena acción antimicrobiana, lo que justifica su uso clínico (AU).

Computational fluid dynamics analysis of the flow of ultrasonic irrigations in root canal / 口腔疾病防治

Objective@#To study the computational fluid dynamics (CFD) characteristics of ultrasonic root canal irrigation when the file was placed at a certain depth in the root canal, to provide a reference for clinical application.@*Methods @#First, scanning laser vibrometry (SLV) was utilized to analyze the characteristics of vibrational ultrasonic files under specific power. Then ICEM CFD 18.0 software was used to establish the root canal ultrasonic irrigation model. The insertion position of the ultrasonic working tip was set 1 mm away from the physiological apical foramen, and cloud images of the results were obtained by FLUENT 18.0 software. Volume fraction, flow velocity and pressure in the root canal were evaluated after setting the computing conditions.@*Results@#The vibration of the ultrasonic working tip was mainly transverse vibration with slight longitudinal vibration. The amplitude of transverse vibration of each part of the working tip was different. Maximum values were observed at the apical end area of the file, and the closer to the base of the file, the smaller the amplitude. The area where the cavitation volume fraction of the rinsing fluid was greater than 0 was concentrated around the working point. The flow rate of the irrigating fluid was up to 2 m/s, within the area 0.2 mm in front of the working tip, the velocity of the irrigating fluid was greater than 0.1 m/s, while within the area 0.8 mm from the root tip, the velocity of the irrigating fluid was small or even zero. The apical pressure value was non-positive when the tip of the file was 1 mm away from the apical foramen in this model.@*Conclusion@# Based on the experimental results, it appears that when the ultrasonic working tip was placed 1 mm short of the working length, the ultrasonic irrigating flow did not overflow the root apical foramen and the irrigation process was relatively safe; the irrigation fluid had a strong irrigation effect within approximately 0.2 mm in front of the working tip.

Effect of edta and qmix ultrasonic activation on the reduction of microorganisms and endotoxins in ex vivo human root canals

Abstract The present study aimed to compare the effectiveness of QMiX and 17% EDTA associated to passive ultrasonic irrigation (PUI) or manual agitation (MA) on the reduction of E. faecalis, E. coli and LPS from root canals. Forty single rooted human teeth were randomly divided into four groups (n=10), according to the final irrigation protocol: EDTA+MA, QMiX+MA, EDTA+PUI, QMiX+PUI. Sample collections were obtained from the root canal content immediately before preparation (baseline-S1), after instrumentation (S2), after final irrigation protocol (S3) and 7 days after instrumentation and final irrigation (S4). The antimicrobial effectivity and on endotoxin content were analyzed by culture procedure (CFU/mL) and LAL assay (EU/mL), respectively. The results were statistically analyzed by Kruskal-Wallis and Friedman test (α=5%). QMiX+MA and QMiX+PUI reduced 100% of E. coli and E. faecalis bacteria and also prevented E. faecalisregrowth at S4. EDTA significantly reduced E. coli, but it was not effective in reducing E. faecalis. All protocols reduced EU/mL when compared to S1, however at S4 there was a significant reduction of EU/mL only in the QMiX+MA and QMiX+PUI groups in relation to S3 and S2, respectively. Final irrigation with QMiX associated with MA or PUI had superior antibacterial efficacy compared to EDTA, eliminating 100% of E. coli and E. faecalis strains. In addition, QMiX+PUI reduced 97.61% of the initial content of LPS.

Resumo O presente estudo objetivou comparar a eficácia do QMiX e do EDTA 17% associado à irrigação ultrassônica passiva (PUI) ou agitação manual (MA) na redução de E. faecalis, E. coli e LPS de canais radiculares. Quarenta dentes humanos unirradiculares foram divididos aleatoriamente em quatro grupos (n = 10), de acordo com o protocolo final de irrigação: EDTA+MA, QMiX+MA, EDTA+PUI, QMiX+PUI. Coletas das amostras foram obtidas a partir do conteúdo do canal radicular imediatamente antes do preparo (inicial-S1), após a instrumentação (S2), após o protocolo final de irrigação (S3) e 7 dias após a instrumentação e irrigação final (S4). A eficácia antimicrobiana e o conteúdo de endotoxina foram analisados ​​por procedimento de cultura (UFC/mL) e ensaio LAL (EU/mL), respectivamente. Os resultados foram analisados estatisticamente pelo teste de Kruskal-Wallis e Friedman (α = 5%). QMiX+MA e QMiX+PUI reduziram 100% das bactérias E. coli e E. faecalis e também preveniram a recolonização de E. faecalis em S4. O EDTA reduziu significativamente E. coli, mas não foi eficaz na redução de E. faecalis. Todos os protocolos reduziram EU/mL quando comparados com S1, no entanto, no S4 houve uma redução significativa de EU/mL apenas nos grupos QMiX+MA e QMiX+PUI em relação a S3 e S2, respectivamente. A irrigação final com QMiX associada a MA ou PUI apresentou eficácia antibacteriana superior em relação ao EDTA, eliminando 100% das cepas de E. coli e E. faecalis. Além disso, QMiX+PUI reduziu 97,61% do conteúdo inicial de LPS.

Effect of root canal irrigants on the bond strength between resin sealants and dentin / 口腔疾病防治

@#When the root canal is filled, the use of the adhesive resin-based sealant to form a strong bond with the dentin reduces microleakage of the apex, enhances the bending resistance of the tooth, and resists the mechanical damage of the pile preparation, thus improving the success rate of root canal treatment. However, during root canal treatment, the use of a rinsing agent may change the tissue structure of the dentin and the wettability of the dentin, thereby affecting the bonding strength between the resin sealing agent and the dentin. In this paper, the effects of a traditional root canal irrigant and several new rinsing agents on the bonding strength of resin sealant and dentin are reviewed. The results show that the traditional root canal rinsing agent NaClO is reduced as the final rinsing agent. The bonding strength of resin sealant to dentin; EDTA affects the biomechanical properties of root dentin, and the removal efficiency is low, which will affect the bond strength between the resin sealant and dentin. EDTA combined with NaClO as a final rinsing agent can improve the bonding strength. Chlorhexidine can also increase the bonding strength between the blocking agent and dentin and can be used as the final rinsing agent. The new rinsing agent MTAD has a negative impact on the resin sealing agent and dentin bond strength. QMix and maleic acid remove smear efficiency with dentin bond strengths greater than or equal to EDTA and can replace EDTA as the final rinse.

Antibacterial effect of urushiol on E. faecalis as a root canal irrigant

OBJECTIVES: The purpose of this study was to compare the antibacterial activity of urushiol against Enterococcus faecalis (E. faecalis) to that of NaOCl. MATERIALS AND METHODS: The canals of thirty two single rooted human teeth were instrumented with Ni-Ti files (ProTaper Next X1, X2, X3, Dentsply). A pure culture of E. faecalis ATCC 19433 was prepared in sterile brain heart infusion (BHI) broth. The teeth were submerged in the suspension of E. faecalis and were incubated at 37℃ for 7 days to allow biofilm formation. The teeth were randomly divided into three experimental groups according to the irrigant used, and a negative control group where no irrigant was used (n = 8). Group 1 used physiologic normal saline, group 2 used 6% NaOCl, and group 3 used 10 wt% urushiol solution. After canal irrigation, each sample was collected by the sequential placement of 2 sterile paper points (ProTaper NEXT paper points, size X3, Dentsply). Ten-fold serial dilutions on each vials, and 100 µL were cultured on a BHI agar plate for 8 hours, and colony forming unit (CFU) analysis was done. The data were statistically analyzed using Kruskal-Wallis and Mann-whitney U tests. RESULTS: Saline group exhibited no difference in the CFU counts with control group, while NaOCl and urushiol groups showed significantly less CFU counts than saline and control groups (p < 0.05). CONCLUSIONS: The result of this study suggests 10% urushiol and 6% NaOCl solution had powerful antibacterial activity against E. faecalis when they were used as root canal irrigants.

Research progress on QMix properties in root canal irrigation / 华西口腔医学杂志

Mechanical instrumentation preparation alone is insufficient to completely remove root canal infection, and chemical irrigation is essential to eliminate infected remnants. An ideal root canal irrigant should completely remove the smear layer, lubricate the root canal, efficiently kill bacteria, induce mild or no inflammatory response in the tissues, and avoid damaging the dentin structure. However, a commercial irrigant that meets all these requirements is currently lacking. QMix is a root canal irrigation mixture of ethylenediamine tetraacetic acid (EDTA), chlorhexidine (CHX) and surfactant. This mixture can remove the smear layer efficiently, and it possesses strong antibacterial effect and good biocompatibility with minimal cytotoxicity. Furthermore, the influence of QMix on the color and micro-hardness of dentin is low, and it can improve the wettability of root canal sealant without affecting its adhesive properties. This review compares the efficiencies of QMix with other irrigants (sodium hypochlorite, CHX, EDTA, SmearClear, and MTAD) in term of smear layer removal, dentine and root canal sealing, cell cytotoxicity, and bacterial growth inhibition.

Comparative Evaluation Of Anti – Bacterial Efficacy Of Sodium Hypochlorite And Carbolic Acid Against Enterococcus Faecalis As Root Canal Irrigant.

Background: Elimination of microorganisms from infected root canal is a complicated & difficult task. Elimination or sufficient reduction of irritants, microorganisms and prevention of recontamination of the root canal after the treatment is the essential factor for successes of the treatment. Methods: Following materials required for this study i.e. 36 teeth prepared for root canal inoculation, Enterococcus faecalis strain, 5 % and 10 % carbolic acid solution, 5.25 % sodium hypochlorite solution, phosphate buffer saline and normal saline solution. An overnight subculture plate of E.faecalis was taken for inoculum preparation and uniform suspension made in normal saline (02 ml) by taking up isolated colonies and adjusted to 0.5 McFarland standard which gives 1.5 X 108 cfu / ml. Result and Conclusion: From this study, we can conclude that 5.25 % NaOCl is one of the superior and successful endodontic irrigant against 5 % and 10% carbolic acid.In our study, result shows that sodium hypochlorite solution is superior to carbolic acid solution. However, as this study is in vitro study, not simulate the oral environment; further few clinical studies are required in evaluation of antimicrobial efficacy of these solutions for predictable and successful endodontic outcome.

Antimicrobial and cytotoxic activity of Ferula gummosa plant essential oil compared to NaOCl and CHX: a preliminary in vitro study

OBJECTIVES: The usage of medicinal plants as natural antimicrobial agents has grown in many fields including dental medicine. The aim of this in vitro study was three-fold: (i) to determine the chemical compositions of the Ferula gummosa essential oil (FGEO), (ii) to compare the antimicrobial efficacy of the oil with sodium hypochlorite (NaOCl) and chlorhexidine (CHX), (iii) to assess the toxic behavior of FGEO in different concentrations compared to 5% NaOCl and 0.2% CHX. MATERIALS AND METHODS: Gas chromatography/mass spectrometry (GC/MS) was used to determine the chemical compositions of the oil. The disk diffusion method and a broth micro-dilution susceptibility assay were exploited to assess the antimicrobial efficacy against Enterococcus faecalis, Staphylococcus aureus, Streptococcus mitis, and Candida albicans. The cytocompatibility of the FGEO was assessed on L929 fibroblasts, and compared to that of NaOCl and CHX. RESULTS: Twenty-seven constituents were recognized in FGEO. The major component of the oil was beta-pinene (51.83%). All three irrigants significantly inhibited the growth of all examined microorganisms compared to the negative control group. FGEO at 50 microg/mL was effective in lower concentration against Enterococcus faecalis than 5% NaOCl and 0.2% CHX, and was also more potent than 0.2% CHX against Candida albicans and Staphylococcus aureus. FGEO was a cytocompatible solution, and had significantly lower toxicity compared to 5% NaOCl and 0.2% CHX. CONCLUSIONS: FGEO showed a promising biological potency as a root canal disinfectant. More investigations are required on the effectiveness of this oil on intracanal bacterial biofilms.

Antimicrobial activity of chlorhexidine in root canals instrumented with the ProTaper Universal™ System

Aim: The purpose of the present study was to evaluate the antimicrobial activity of 0.2%, 1%, and2% chlorhexidine in root canals instrumented with the ProTaper Universal™ system. Methods:Fifty human mandibular premolar teeth were infected with a mixture of Candida albicans,Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus. The specimens were randomly divided into 5 groups with 10 root canals according to the irrigant used. All root canals were instrumented with the ProTaper Universal™ system. Assessment of the antimicrobial action of the irrigant was performed before, during, and after instrumentation. Data were analyzed statistically by Chi-squared test and the Fisher exact test at 5% significance level. Results: The0.2% chlorhexidine solution was ineffective against all test microorganisms. The 1% chlorhexidinesolution was effective in eliminating P. aeruginosa and C. albicans after the use of the F1 and F3instruments, respectively. The 2% chlorhexidine solution was effective at killing S. aureus, P.aeruginosa and C. albicans after the use of the S1 instrument. There were statistically significant differences (p<0.05) between the concentrations of chlorhexidine and the instruments used.Conclusions: The 0.2% chlorhexidine solution in combination with rotary instrumentation was ineffective against all test microorganisms. The 1% chlorhexidine solution was ineffective against S. aureus and E. faecalis. The 2% chlorhexidine solution was not sufficient to inactivate E.faecalis.

Comparison of Antibacterial effect of Listerine(R) with Various root canal irrigants / 대한치과보존학회지

The purpose of this study is to compare the antibacterial effect of Listerine(R) on two microorganisms (P. gingivalis and E. faecalis) with various root canal irrigants (NaOCl, CHX, EDTA) and to identify possibility of using Listerine(R) as a root canal irrigant. Porphyromonas gingivalis ATCC 3327 and Enterococcus faecalis ATCC 29212 were used in this experiment. For the test irrigants, 0.5%, 1%, 2.5%, 5.25% NaOCl, 0.1%, 0.2%, 1%, 2% CHX, 0.5M EDTA (18.6% EDTA) and Listerine(R) were prepared. Distiled water was used as control. Two methods-1) Comparison of turbidity in broth and 2) Agar diffusion test-were used to determine the extent of antibacterial effect of Listerine(R) and to compare it with that of NaOCl, CHX, and EDTA. All solutions tested were effective against two bacterial strains compared with control (p<0.001). Any concentration of NaOCl, CHX, and EDTA showed similarly high effectiveness against all bacterial strains. In all experiment, Listerine(R) showed significantly low antibacterial effect compared with the other root canal irrigants (p<0.05). In conclusion, the results reflect remarkably low antibacterial effect of Listerine(R) as compared with root canal irrigants in general so it is not suitable for the root canal irrigant.

Efeito antibacteriano in vitro das soluções tetraclean, MTAD e modificações: teste de contato direto e ação sobre o biofilme / In vitro antibacterial effect of tetraclean, MTAD and modifications: direct exposure test and effect on the biofilm

O objetivo deste estudo foi avaliar a atividade antibacteriana das soluções Tetraclean®, MTAD® e modificações desta formulação sobre uma cepa de Enterococcus faecalis pelo teste de contato direto e frente ao biofilme. Na metodologia de contato direto, uma suspensão de E. faecalis foi exposta às soluções irrigadoras, por períodos de 30 s, 1, 3 e 10 min, e um agente neutralizante foi utilizado. As colônias viáveis foram quantificadas após diluições seriadas e cultura em placas de ágar. Para determinação do número inicial de UFC, água esterilizada foi usada como controle. Para o crescimento do biofilme, amostras de biofilme dentário foram suspensas em BHI (Brain Heart Infusion), e incubadas por 14 dias em anaerobiose, tendo como substrato, discos de hidroxiapatita. Após o período de incubação, os biofilmes foram expostos às soluções irrigadoras por períodos de 30 s, 1 e 3 min. Os biofilmes corados com o Live/Dead Baclight stain (Molecular Probes, Europe BV), que diferencia células viáveis (verde) e células não-viáveis (vermelho) foram observados na microscopia confocal. As imagens do biofilme obtidas pelo software EZ-C1 for Nikon foram transferidas para análise quantitativa da proporção de células viáveis sobre o total de células do biofilme para o software Imaris 5.0. No teste de contato direto, o Tetraclean® eliminou completamente o E. faecalis em 30 s, enquanto o MTAD® e o MTAD® + CTR 0,01% eliminaram após 10 min, e o MTAD® + CTR 0,1% resultou em culturas negativas após 3 min de contato com a suspensão bacteriana. Quando removido o Tween 80 do MTAD®, e acrescida a CTR 0,01%, obteve-se culturas negativas após 1 minuto. Os resultados obtidos pelo método de exposição ao biofilme confirmaram os achados do teste de contato direto...

The aim of this study was to evaluate the antibacterial effect of MTAD® and Tetraclean®. The tests were performed on Enterococcus faecalis using the direct exposure test and an in vitro biofilm model. Alternative formulations to MTAD® were also included in the experiments: MTAD® + 0.01% cetrimide (CTR); MTAD® + 0.1% CTR; MTAC (the detergent Tween 80 was substituted for cetrimide) with 0.01% CTR and MTAC (0.1% CTR). In the direct exposure test, a bacterial suspension was mixed with the irrigation solutions. After 30 seconds, 1 minute, 3 minutes and 10 minutes, an inactivator agent was used. The number or viable colonies were calculated after serial 10-fold dilutions and culture in agar plates. To calculate the initial number of colonies, sterilized water was used as a control. Dental biofilm samples were suspended in BHI broth and incubated in anaerobic conditions in hidroxiapatite discs. After incubation for 14 days, the biofilms were exposed to the irrigation solutions for 30 seconds, 1 minute and 3 minutes. Live/Dead Baclight stain (Molecular Probes, Europe BV) was used to diferentiate viable cells (Green) and non viable cells (Red). The samples were observed in the Confocal Laser Microscope. The biofilm images in 3D obtained in the EZ-C1 for Nikon software were transfered to quantitative analysis in the Imaris 5.0 software. The software calculated the ratio of green cells. In the direct exposure test, Tetraclean® and MTAC (0.1% CTR) erradicated E. faecalis in 30 s. MTAD® and MTAD® + 0.01% CTR eliminated E. faecalis after 10 min. MTAD® + 0.1% CTR resulted in negative culture after 3 min. Negative cultures were obtained after 1 min when MTAC (0.01% CTR) was used. The findings from the biofilm exposure method confirmed the results from direct exposure test. The Kruskal-Wallis statistical analysis showed a significant difference in time exposure to irrigant (P<0.001)...

The effect of MTAD on the apical leakage of obturated root canals: an electrochemical study / 대한치과보존학회지

The purpose of this study was to evaluate the effect of newly developed endodontic root canal cleanser (MTAD) on the apical leakage of obturated root canal using an electrochemical method. Canals of 60 extracted single-rooted human teeth were prepared by using a crown-down technique with rotary nickel-titanium files. In Group 1 (positive control group) and 2 (negative control group), 5.25% NaOCl was used as a canal irrigant and no canal wall treatment was done. In group 3, only 5.25% NaOCl were used as canal irrigant, canal wall treatment and final rinse. In group 4, specimens were irrigated with 5.25% NaOCl, treated with 5 ml of 17% EDTA for 5 minutes and final rinsed with 5.25% NaOCl. Specimens of group 5 were irrigated with 1.3% NaOCl and treated with 5 ml of MTAD for 5 minutes. All root canals are dried with paper points and obtuated with gutta-percha and AH plus as a sealer using a continuous wave of condensation technique except in the group 1. The electrical resistance between the standard and experimental electrodes in canals was measured over a period of 10 days. Rising of apical leakage with time was observed for all the groups. Group 4 and 5 showed lower apical leakage than group 3 but differences between the group 3, 4 and 5 were no statistical significance at any measurement time.

Evaluation of Sodium Dichloroisocyanurate as a root canal irrigation solution; Cl- concentration, pH, Cytotoxicity and Antimicrobial effect in vitro / 대한치과보존학회지

The purpose of this study was to evaluate the clinical applications of the Sodium Dichloroisocyanurate effervescent tablet as a routine root canal irrigant by performing several in vitro tests such as Cl- content, cytotoxicity, antimicrobial effect as well as its pH level compared to the equivalent concentration of sodium hypochlorite solution. 1. Sodium Dichloroisocyanurate demonstrated lower level of Cl- concentation than each dilution of sodium hypochlorite solution. Both solution has increased level of Cl- as the concentration of each solution increased. There was no significant change of Cl- concentration in sodium hypochlorite as time goes by. However, Cl- concentration in Sodium Dichloroisocyanurate was increased. 2. The antimicrobial effects of both solutions were increased when their concentrations were increased. One day after dilution, antimicrobial effect of Sodium Dichloroisocyanurate was slightly higher than sodium hypochlorite, however, there was no difference in 1 week dilution solution. One month dilution solution of sodium hypochlorite still retain its activity, but antimicrobial effect of Sodium Dichloroisocyanurate was drastically decreased 1 month after dilution. 3. The cytotoxicity of Sodium Dichloroisocyanurate was rather higher than same concentration of sodium hypochlorite solution until 1 week after dilution. Then in 1 month, cytotoxicity of Sodium Dichloroisocyanurate was decreased than that of 1 week dilution solution, especially 4% Sodium Dichloroisocyanurate solution has almost no toxicity. However, 1% and 2% sodium hypochlorite solution has unchanged moderate degree of cytotoxicity after the dilution. Furthermore, 4% sodium hypochlorite solution showed high level of toxicity. 4. The pH level of Sodium Dichloroisocyanurate showed that the solution was weak acid (pH5). On the other hand, sodium hypochlorite was revealed as a strong alkaline solution (pH12). There was no change in pH following the dilution of each solution. As results, Sodium Dichloroisocyanurate solution fully satisfy the basic requirements as a root canal irrigation solution. However, we strongly recommend to use this solution clinically in low concentration and try to apply into the root canal within 1 week after dilution.