This study compared the antimicrobial efficacy of QMix 2 in 1, sodium hypochlorite (NaOCl), and chlorhexidine (CHX) against Enterococcus faecalis and Candida albicans. Eighty single-rooted teeth were inoculated with either E. faecalis or C. albicans and then irrigated with one of the three test irrigants. Colony forming units were significantly lower in canals irrigated with QMix 2 in 1 compared to NaOCl and CHX, demonstrating greater antimicrobial efficacy. NaOCl and CHX showed similar efficacy with no significant difference. This study suggests that QMix 2 in 1 is more effective at eliminating E

1. Journal of Conservative Dentistry | Mar-Apr 2015 | Vol 18 | Issue 2128
Comparative evaluation of antimicrobial
efficacy of QMixTM
2 in 1, sodium hypochlorite,
and chlorhexidine against Enterococcus faecalis
and Candida albicans
Soujanya Elakanti, Gayathri Cherukuri 1
,Venkateswara G Rao1
, Veeramachaneni Chandrasekhar, Anitha S Rao,
Muralidhar Tummala
Department of Conservative Dentistry and Endodontics, and 1
Oral Pathology and Microbiology, Mamata Dental College, Khammam,
Andhra Pradesh, India
A b s t r a c t
Aim/Objective: The aim of this study is to compare the antimicrobial efficacy of QMixTM
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, QMixTM
2 in 1; and Group ID, 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 37°C 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 QMixTM
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: QMixTM
2 in 1 demonstrated significant antimicrobial efficacy against E. faecalis and C. albicans.
Keywords: Candida albicans; chlorhexidine; Enterococcus faecalis; QMixTM
2 in 1; sodium hypochlorite
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.[3]
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.[4]
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.[5,6]
Address for correspondence:
Dr. Veeramachaneni Chandrasekhar, Department of Conservative
Dentistry and Endodontics, Mamata Dental College,
Khammam - 507 002, Andhra Pradesh, India.
E-mail: vcs_1818@yahoo.co.in
Date of submission : 17-09-2013
Review completed : 19-12-2014
Date of acceptance : 02-01-2015
Access this article online
Quick Response Code:
Website:
www.jcd.org.in
DOI:
10.4103/0972-0707.153067
Original Article
INTRODUCTION
One of the most important objectives of endodontic therapy
is to completely eliminate intracanal microorganisms from
the root canal system to create favorable environment for
healing and to prevent reinfection in order to achieve long-
term success.[1]
Endodontic infections 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.[2]
Although several factors
contribute to endodontic failures, the literature reported
that persistent intraradicular or secondary infection is

2. Soujanya, et al.: Antimicrobial efficacy of QMixTM
2 in 1
129Journal of Conservative Dentistry | Mar-Apr 2015 | Vol 18 | Issue 2
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.[7,8]
Due to complex anatomy of root canal system, an effective
disinfection is achieved by augmenting mechanical
preparation with antimicrobial irrigants. Irrigants help in
removal of debris and microorganisms form the canal that
cannot be reached by endodontic instruments.[9]
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.[10,11]
Sodium hypochlorite (NaOCl) has been widely used as root
canal irrigant due to its potent antimicrobial activity and
tissue dissolving ability.[12]
But it has several undesirable
characteristics such as tissue toxicity, risk of subcutaneous
emphysema, allergic potential, and disagreeable smell and
taste.[13]
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, has
bactericidal effect due to precipitation and coagulation of
intracellular constituents.[14,15]
QMixTM
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.[16]
QMix had stronger antibacterial
effects against young and old E. faecalisbiofilm in dentin[17]
and had stronger antibacterial effect against E. faecalis
present in deep dentin.[18]
Studies are needed to evaluate
the antimicrobial efficacy of QMixTM
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 QMixTM
2 in 1 with 5.25% NaOCl
and 2% CHX digluconate against E. faecalis and C. albicans.
MATERIALS AND METHODS
Eighty sound healthy human mandibular premolar teeth
extracted for orthodontic treatment were taken. 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
121°C and 15lb of pressure to ensure complete sterilization
within the canal space. Efficacy of sterilization was tested
by sampling the root canal with paper points. 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 37°C 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 × 108
bacteria/mL). E. faecalis suspension
of 10 µL was injected into Group I samples containing
40 teeth and 10 µL 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 37°C
for 3 days. E. faecalis has ability to form biofilm on root
canal walls. 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%

3. Soujanya, et al.: Antimicrobial efficacy of QMixTM
2 in 1
Journal of Conservative Dentistry | Mar-Apr 2015 | Vol 18 | Issue 2130
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 QMixTM
2 in 1 (Dentsply
Tulsa Dental Specialities, Tulsa, OK), subgroup ID 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 µL) of
the sample from the canal. Using a bacterial inoculation
loop; the bacterial suspension was placed on Sabouraud
dextrose agar and BHI agar. The plates were incubated at
37°C for 24 h and then number of colony forming units
(CFUs) was counted.
Log transformation of absolute bacterial CFU was
performed. Mean Log CFUs were compared among the
groups using analysis of variance (ANOVA) followed by
post-hoc Games-Howell test.
RESULTS
Results were analyzed with the Statistical Package for
Social Sciences (SPSS)/Predictive Analytics Software
(PASW) version 18 software. Table 1 shows the mean CFUs
of E. faecalis and C. albicans. QMixTM
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).
DISCUSSION
The main goal of chemomechanical preparation of infected
root canals is to completely eliminate intracanal bacteria
and prevention of recontamination after treatment.[1]
This
laboratory study was aimed to evaluate the antimicrobial
efficacy of QMixTM
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.[19]
E. faecalis and C. albicans are frequently isolated in root
canals with pulpal infection and in secondary/persistent
endodontic infections.[20]
In the present study QMixTM
2 in 1 has shown good
antimicrobial efficacy and statistically superior to all
other irrigants (P < 0.01). The reason could be effective
functioning of individual constituents of it. 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+2
and
Ca+2
) from bacterial cell membrane and increasing its
permeability.[21]
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.[17]
QMix and 6% NaOCl had stronger antibacterial
effect against E. faecalis which resides deep in dentin than
1% and 2% NaOCl and 2% CHX.[18]
QMixTM
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.[7]
EDTA present in QMixTM
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.
NaOCl has effectively killed E. faecalis and C. albicans.
But there was statistically significant difference present
between QMixTM
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.[10]
Many in vitro and in vivo studies have proved NaOCl has
good antimicrobial efficacy against E. faecalis.[22-24]
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.[22]
CHX is a broad spectrum antimicrobial agent with
substantivity property. The positively charged ions released
Table 1: Comparison of CFUs among the study groups
Group I Subgroups Mean (N = 10) SD
Enterococcus faecalis 5.25% NaOCl 2.88†
0.09
2% Chlorhexidine 2.76†
0.18
QMixTM
2 in 1 1.36*
1.18
Saline 3.20 0.08
Candida albicans 5.25% NaOCl 2.46†
0.87
2% Chlorhexidine 2.37†
0.85
QMixTM
2 in 1 1.06*
1.12
Saline 3.33 0.30
*Indicates statistically significant difference at P = 0.001, †
indicates no statistical
significant difference at P = 0.001 (post-hoc test), SD: Standard deviation

4. Soujanya, et al.: Antimicrobial efficacy of QMixTM
2 in 1
131Journal of Conservative Dentistry | Mar-Apr 2015 | Vol 18 | Issue 2
by CHX can adsorb into dentin and prevent microbial
colonization.[25]
CHX has shown good antimicrobial efficacy
against E. faecalis and C. albicans, but it is inferior to QMixTM
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.[26]
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.[27]
The effectiveness of NaOCl and CHX on C. albicans is well
documented in literature.[25,28,29]
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.[29]
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. This accounted for
a reduction in the microbial counts. Kuruvilla and Kamath
reported a significant reduction in microbial counts with
usage of saline in canals without mechanical preparation.[30]
CONCLUSION
Within the limitations of this study, QMixTM
2 in 1
demonstrated significant antimicrobial efficacy against
E. faecalis and C. albicans.
REFERENCES
1. Brito PR, Souza LC, Machado de Oliveira JC, Alves FR, De-Deus G,
Lopes HP, et al. Comparison of the effectiveness of three irrigation
techniques in reducing intracanal Enterococcus faecalis populations:
An in vitro study. J Endod 2009;35:1422-7.
2. Liu H, Wei X, Ling J, Wang W, Huang X. Biofilm formation capability of
Enterococcus faecalis cells in starvation phase and its susceptibility to
sodium hypochlorite. J Endod 2010;36:630-5.
3. Hoelscher AA, Bahcall JK, Maki JS. In vitro evaluation of the antimicrobial
effects of a root canal sealer-antibiotic combination against Enterococcus
faecalis. J Endod 2006;32:145-7.
4. Tirali RE, Turan Y, Akal N, Karahan ZC. In vitro antimicrobial activity
of several concentrations of NaOCl and Octenisept in elimination of
endodontic pathogens. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod 2009;108:e117-20.
5. Shon W, Lim S, Bae KS, Baek S, Lee W. The expression of
alpha 4 integrins by human polymorphonuclear neutrophils in
response to sonicated extracts of Enterococcus faecalis. J Endod
2005;31:369-72.
6. Kayaoglu G, Erten H, Bodrumlu E, Ørstavik D. The resistance of
collagen-associated, planktonic cells of Enterococcus faecalis to
calcium hydroxide. J Endod 2009;35:46-9.
7. Chandra SS, Miglani R, Srinivasan MR, Indira R. Antifungal efficacy
of 5.25% sodium hypochlorite, 2% chlorhexidine gluconate, and 17%
EDTA with and without an antifungal agent. J Endod 2010;36:675-8.
8. ValeraMC,SilvaKC,MaekawaLE,CarvalhoCA,Koga-ItoCY,Camargo CH,
et al. Antimicrobial activity of sodium hypochlorite associated with
intracanal medication for Candida albicans and Enterococcus faecalis
inoculated in root canals. J Appl Oral Sci 2009;17:555-9.
9. Dametto FR, Ferraz CC, Gomes BP, Zaia AA, Teixeira FB,
de Souza-Filho FJ. In vitro assessment of the immediate and prolonged
antimicrobial action of chlorhexidine gel as an endodontic irrigant
against Enterococcus faecalis. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod 2005;99:768-72.
10. Oliveira DP, Barbizam JV, Trope M, Teixeira FB. In vitro antibacterial
efficacy of endodontic irrigants against Enterococcus faecalis. Oral Surg
Oral Med Oral Pathol Oral Radiol Endod 2007;103:702-6.
11. Retamozo B, Shabahang S, Johnson N, Aprecio RM, Torabinejad M.
Minimum contact time and concentration of sodium hypochlorite
required to eliminate Enterococcus faecalis. J Endod 2010;36:520-3.
12. Siqueira JF Jr, Paiva SS, Rocas IN. Reduction in the cultivable
bacterial populations in infected root canals by a chlorhexidine-based
antimicrobial protocol. J Endod 2007;33:541-7.
13. Murray PE, Farber RM, Namerow KN, Kuttler S, Garcia-Godoy F.
Evaluation of morinda citrifolia as an endodontic irrigant. J Endod
2008;34:66-70.
14. Wang CS, Arnold RR, Trope M, Teixeira FB. Clinical efficiency of 2%
chlorhexidine gel in reducing intracanal bacteria. J Endod 2007;33:1283-9.
15. Xu Y, Young MJ, Battaglino RA, Morse LR, Fontana CR, Pagonis TC, et al.
Endodontic antimicrobial photodynamic therapy: Safety assessment in
mammalian cell cultures. J Endod 2009;35:1567-72.
16. Dai L, Khechen K, Khan S, Gillen B, Loushine BA, Wimmer CE, et al.
The effect of Qmix, an experimental antibacterial root canal irrigant, on
removal of canal wall smears layer and debris. J Endod 2011;37:80-4.
17. Wang Z, Shen Y, Haapasalo M. Effectiveness of endodontic disinfecting
solutions against young and old Enterococcus faecalis biofilms in dentin
canals. J Endod 2012;38:1376-9.
18. Ma J, Wang Z, Shen Y, Haapasalo M. A new non invasive model to study
the effectiveness of dentin disinfection by using confocal laser scanning
microscopy. J Endod 2011;37:1380-5.
19. Orstavik D, Haapasalo M. Disinfection by endodontic irrigants and
dressings of experimentally infected dentinal tubules. Endod Dent
Traumatol 1990;6:142-9.
20. Ercan E, Dalli M, Dülgergil CT. In vitro assessment of the effectiveness
of chlorhexidine gel and calcium hydroxide paste with chlorhexidine
against Enterococcus faecalis and Candida albicans. Oral Surg Oral
Med Oral Pathol Oral Radiol Endod 2006;102:e27-31.
21. StojicicS,ShenY,QianW,JohnsonB,HaapasaloM.Antibacterialandsmear
layer removal ability of a novel irrigant, Qmix. Int Endod J 2012;45:363-71.
22. Fidalgo TK, Barcelos R, Portela MB, Soares RM, Gleiser R, Silva-Filho FC.
Inhibitory activity of root canal irrigants against Candida albicans,
Enterococcus faecalis and Staphylococcus aureus. Braz Oral Res
2010;24:406-12.
23. Berber VB, Gomes BP, Sena NT, Vianna ME, Ferraz CC, Zaia AA,
et al. Efficacy of various concentrations of NaOCl and instrumentation
techniques in reducing Enterococcus faecalis within root canals and
dentinal tubules. Int Endod J 2006;39:10-7.
24. Sassone LM, Fidel RA, Murad CF, Fidel SR, Hirata R Jr. Antimicrobial
activity of sodium hypochlorite and chlorhexidine by two different tests.
Aust Endod J 2008;34:19-24.
25. Mohammadi Z, Abbott PV. The properties and applications of
chlorhexidine in endodontics. Int Endod J 2009;42:288-302.
26. Pavlovic V, Zivkovic S. Chlorhexidine as a root canal
irrigant — Antimicrobial and scanning electron microscopic evaluation.
Srp Arh Celok Lek 2010;138:557-63.
27. Arslan S, Ozbilge H, Kaya EG, Er O. In vitro antimicrobial activity of propolis,
BioPure MTAD, sodium hypochlorite, and chlorhexidine on Enterococcus
faecalis and Candida albicans. Saudi Med J 2011;32:479-83.
28. Sen BH, Safavi KE, Spangberg LS. Antifungal effects of sodium
hypochlorite and chlorhexidine in root canals. J Endod 1999;25:235-8.
29. Ruff ML, McClanahan SB, Babel BS. In vitro antifungal efficacy of four
irrigants as a final rinse. J Endod 2006;32:331-3.
30. Kuruvilla JR, Kamathmp MP. Antimicrobial activity of 2.5% sodium
hypochlorite and 0.2% chlorhexidine gluconate separately and
combined, as endodontic irrigants. J Endod 1998;24:472-6.
How to cite this article: Elakanti S, Cherukuri G, Rao VG,
Chandrasekhar V, Rao AS, Tummala M. Comparative evaluation
of antimicrobial efficacy of QMix™ 2 in 1, sodium hypochlorite,
and chlorhexidine against Enterococcus faecalis and Candida
albicans. J Conserv Dent 2015;18:128-31.
Source of Support: Nil, Conflict of Interest: None declared.

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