are polymicrobial in nature with predominant anaerobic microorganisms . bacteria and their metabolic products , enzymes , and toxins play a vital role in the initiation , propagation , and persistence of pulpal and periradicular pathosis .
although several factors contribute to endodontic failures , the literature reported that persistent intraradicular or secondary infection is the major etiology for failed endodontic therapy .
studies have shown that microflora in failed root canal therapy are different from those found in untreated teeth .
enterococcus faecalis ( e. faecalis ) and candida albicans ( c. albicans ) are considered to be the most resistant species in infected root canals and they are often associated with endodontic treatment failures .
e. faecalis is a gram positive , facultative anaerobic cocci commonly found in persistent root canal infection and commonly recovered in over one - third of the canal of endodontically treated teeth with persisting periapical lesions . c. albicans , the most predominant and commonly isolated yeast in failed root canal treatment with periradicular pathosis .
it may gain access to the root canal from the oral cavity as a result of poor asepsis during endodontic treatment procedures or because of coronal leakage .
it is a dentinophilic aerobic microorganism able to survive in harsh ecologic environment of root canal . due to complex anatomy of root canal system ,
irrigants help in removal of debris and microorganisms form the canal that can not be reached by endodontic instruments .
an ideal root canal irrigant should have good antimicrobial efficacy , nontoxic to periapical tissues , capable of dissolving necrotic tissue , able to lubricate the canal , and help in smear layer removal .
sodium hypochlorite ( naocl ) has been widely used as root canal irrigant due to its potent antimicrobial activity and tissue dissolving ability .
but it has several undesirable characteristics such as tissue toxicity , risk of subcutaneous emphysema , allergic potential , and disagreeable smell and taste .
chlorhexidine ( chx ) digluconate has been suggested as root canal irrigant because of its good antimicrobial efficacy and substantivity .
it seems to act by adsorbing onto the cell wall of microorganisms resulting in leakage of intracellular components . at low concentration , it has bacteriostatic effect . at higher concentration ,
qmix 2 in 1 , an experimental irrigating solution , contains a mixture of a bisbiguanide antimicrobial agent , a polyamino carboxylic acid calcium chelating agent ; saline ; and a surfactant .
it was evaluated as an effective irrigant similar to 17% ethylenediaminetetraacetic acid ( edta ) in removing canal wall smear layer after the use of 5.25% naocl as the initial rinse .
qmix had stronger antibacterial effects against young and old e. faecalisbiofilm in dentin and had stronger antibacterial effect against e. faecalis present in deep dentin .
studies are needed to evaluate the antimicrobial efficacy of qmix 2 in 1 in comparison with naocl and chx against e. faecalis and c. albicans .
thus , the aim of the present study is to compare the antimicrobial efficacy of qmix 2 in 1 with 5.25% naocl and 2% chx digluconate against e. faecalis and c. albicans .
teeth were cleansed using ultrasonic scalers to render them free from calculus and tissue tags , following which they were stored in physiological saline until use .
the teeth were decoronated at the cementoenamel junction using diamond disc ( isomet 2000 ; buehler ltd , lake bluff , il ) and the root lengths was standardized to approximately 14 mm .
pulp was extirpated and working length was established 1 mm short of apex where the file exited the apical foramen .
gates glidden drills # 3 ( mani inc , tachigi - ken , japan ) were used to prepare the root canal orifices ( 3 mm ) .
apical preparation was done using k - file ( dentsply maillefer , ballaigues , switzerland ) up to the iso size # 40 .
canals were irrigated copiously with physiologic saline ( 0.9 w / v nacl ) after each instrument . each canal
was then rinsed with 1ml of 17% edta ( prime dental product ) for 1 min followed by 3 ml of 5.25% naocl ( prime dental product , mumbai , india ) to facilitate the removal of smear layer .
the roots were coated with nail varnish and apical foramen sealed with type ii glass ionomer cement ( gic ; gc fuji , tokyo , japan ) .
the roots were sterilized in an autoclave for 15 min at 121c and 15 lb of pressure to ensure complete sterilization within the canal space .
the paper points were placed into a test tube containing 1 ml reduced transport fluid , vortexed for 10 s , placed onto brain heart infusion ( bhi ) agar ( himedia laboratories , mumbai , india ) and sabouraud dextrose agar ( himedia laboratories , mumbai , india ) , incubated at 37c for 48 h , and examined for growth . a suspension of e. faecalis ( atcc 29212 ) and c. albicans ( courtesy ibms institute , chennai , india ) were adjusted to 0.5 turbidity on the mcfarland scale ( 1.5  10 bacteria / ml ) .
e. faecalis suspension of 10 l was injected into group i samples containing 40 teeth and 10 l suspension of c. albicans into group ii samples containing 40 teeth using a micropipette in a class ii vertical laminar airflow cabinet to prevent any airborne contamination . then inoculated specimens with e. faecalis
were placed in vials filled with bhi agar and inoculated specimens with c. albicans were placed in vials filled with sabouraud dextrose agar , then inoculum was added every day and incubated aerobically at 37c for 3 days .
after 3 days , aliquots were taken from each tooth using a syringe and plated on bhi agar to verify the growth of e. faecalis and sabouraud dextrose agar to verify the growth of c. albicans . at the end of 3 days
, teeth were removed from the vials and excess fluid in canal was removed with sterile paper points .
the specimens from each group were divided into four subgroups ( a , b , c , and d ) of 10 teeth each depending on the experimental irrigating solution used .
test solutions used were : subgroup ia and iia : 3 ml of 5.25% naocl ( prime dental product , mumbai , india ) , subgroup ib and iib : 3 ml of 2% chx ( dentochlor , ammdent , pb , india ) , subgroup ic and iic : 3 ml of qmix 2 in 1 ( dentsply tulsa dental specialities , tulsa , ok ) , subgroup i d and iid : 3 ml of 0.9% saline ( positive control ) .
irrigation was accomplished using 30 gauge prorinse needle ( dentsply ) placed 1 - 2 mm short of the working length .
the time of contact of each irrigant was 1 min and a final flush was done with 5ml of distilled water to terminate the action of irrigant . a small amount of saline solution was introduced into the canal , and an endodontic hand file was used in a filing motion to a level 1 mm short of the root apex .
sterile 30 gauge needle was used to collect 0.01ml ( 10 l ) of the sample from the canal . using a bacterial inoculation loop ;
the plates were incubated at 37c for 24 h and then number of colony forming units ( cfus ) was counted .
mean log cfus were compared among the groups using analysis of variance ( anova ) followed by post - hoc games - howell test .
results were analyzed with the statistical package for social sciences ( spss)/predictive analytics software ( pasw ) version 18 software .
qmix 2 in 1 was the most effective and statistically significant when compared with 5.25% naocl and 2% chx ( p < 0.001 ) .
there is no statistical significant difference between 5.25% naocl and 2% chx ( p > 0.001 ) .
the main goal of chemomechanical preparation of infected root canals is to completely eliminate intracanal bacteria and prevention of recontamination after treatment .
this laboratory study was aimed to evaluate the antimicrobial efficacy of qmix 2 in 1 , naocl , and chx against e. faecalis and c. albicans .
the in vitro model developed by orstavik and haapasalo has been used to assess antimicrobial efficacy of irrigants .
e. faecalis and c. albicans are frequently isolated in root canals with pulpal infection and in secondary / persistent endodontic infections . in the present study qmix 2 in 1
has shown good antimicrobial efficacy and statistically superior to all other irrigants ( p < 0.01 ) .
surface active agent lowers the surface tension of solution and increases their wett ability and enables better penetration of an irrigant in the root canal .
the potential benefit of bisbiguanide in this mixture is that it prevents the microbial colonization on dentin surface .
calcium chelating agent can cause cell wall damage in gram negative bacteria by chelating and removing divalent cations ( mg and ca ) from bacterial cell membrane and increasing its permeability .
wang et al . , concluded that qmix and 6% naocl had stronger antibacterial effects against young and old e. faecalis biofilm in dentin than 2% naocl and 2% chx .
qmix and 6% naocl had stronger antibacterial effect against e. faecalis which resides deep in dentin than 1% and 2% naocl and 2% chx .
qmix 2 in 1 showed statistically superior antimicrobial efficacy against c. albicans . c. albicans was more resistant to irrigating solutions when the smear layer was present .
edta present in qmix 2 in 1 effectively removes the smear layer and chx prevents the colonization of fungi on dentinal walls .
there have been very few published studies examining the effect of antimicrobial agents on fungi .
those articles that have been published are difficult to compare because of variations in methodology and the agents tested .
but there was statistically significant difference present between qmix 2 in 1 and naocl ( p < 0.001 ) .
naocl exerts its antibacterial effect by inducing the irreversible oxidation of sulfhydryl groups of essential bacterial enzymes , resulting in disulfide linkages , with consequent disruption of the metabolic function of bacterial cells .
many in vitro and in vivo studies have proved naocl has good antimicrobial efficacy against e. faecalis .
fidalgo et al . , evaluated the antimicrobial activity of naocl , citric acid , and edta against e. faecalis , c. albicans , and staphylococcus aureus and concluded that 2.5% and 5.25% naocl are microbiocides against s. aureus , while 0.5% and 1% naocl are only microbiostatic against the tested e. faecalis and c. albicans .
the positively charged ions released by chx can adsorb into dentin and prevent microbial colonization .
chx has shown good antimicrobial efficacy against e. faecalis and c. albicans , but it is inferior to qmix 2 in 1 in this study ( p < 0.001 ) .
pavlovic and zivkovic concluded that 2% chx solution was effective against s. aureus , streptococcus mutans , e. faecalis , escherichia coli , and c. albicans .
there was no statistical significant difference between chx and naocl ( p > 0.01 ) .
arslan et al . , concluded that propolis , biopure mtad , 5% naocl , and 2% chx showed good antimicrobial activity against e. faecalis and c. albicans .
ruff et al . , investigated the efficacy of 6% naocl , 2% chx , 17% edta , and biopure mtad against c. albicans and concluded that 2% chx and 6% naocl were equally effective and statistically superior to 17% edta and biopure mtad . saline has also shown considerable reduction in the cfu counts of e. faecalis and c. albicans . the mechanical shaping and cleaning of the canals and irrigation with saline served to flush out the debris from the canals .
kuruvilla and kamath reported a significant reduction in microbial counts with usage of saline in canals without mechanical preparation .
within the limitations of this study , qmix 2 in 1 demonstrated significant antimicrobial efficacy against e. faecalis and c. albicans .
 aim / objective : the aim of this study is to compare the antimicrobial efficacy of qmix 2 in 1 , sodium hypochlorite ( naocl ) , and chlorhexidine ( chx ) against enterococcus faecalis and candida albicans.materials and methods : eighty freshly extracted , single - rooted human mandibular premolar teeth were instrumented and autoclaved . 
 samples were divided into two groups of 40 teeth each based on the type of microorganism used . 
 group i was inoculated with e. faecalis and group ii with c. albicans and incubated for 3 days . 
 each group was subdivided into four subgroups based on the type of irrigant used . 
 group ia , iia , 5.25% naocl ; group ib , iib , 2% chx ; group ic , iic , qmix 2 in 1 ; and group i d , iid , 0.9% saline ( the control group ) . 
 ten microliters of the sample from each canal was taken and was placed on brain heart infusion agar and sabouraud dextrose agar . 
 the plates were incubated at 37c for 24 h and colony forming units ( cfus ) that were grown were counted . 
 data was analyzed with analysis of variance ( anova ) followed by post - hoc games - howell test.results:the greatest antimicrobial effects were observed in samples treated with qmix 2 in 1 ( p < 0.001 ) . 
 no statistical significant difference was found between 5.25% naocl and 2% chx ( p > 0.001 ) against e. faecalis and c. albicans.conclusion : qmix 2 in 1 demonstrated significant antimicrobial efficacy against e. faecalis and c. albicans . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
CONCLUSION