ABSTRACT
I N TROD UCTI ON
Cleaning and disinfect ion are t he m ain obj ect ives o f r o o t - can al p r ep ar at i o n . Th o r o u g h cl ean i n g r em ov es m i cr o o r g an i sm s, p er m i t s ad ap t at i o n
of illing materials and enhances the action of
int racanal m edicam ent s. The choice of an irrigant is of gr eat im por t ance because t hey act as lubr icant s
during instrumentation, lush debris and bacteria
ou t of t h e can al, an d r eact w it h pu lp, n ecr ot ic t issues and m icr oor ganism s. Num er ous ir r igant s have been recom m ended for clinical use16. I rrigat ion
w it h dist illed wat er is effect ive at r em oving loose d eb r is, b u t h as lit t le ef f ect on sm ear lay er or m icroorganism s1. Sodium hypochlorit e ( NaOCl) has
been ext ensively used as an ir r igat ing solut ion for several decades, and it is w idely r ecom m ended9.
I t s excellent pr oper t ies of t issue dissolut ion and ant im icr obial act ivit y m ake it t he ir r igant of choice
Effect of aquat ine endodont ic cleanser on sm ear
layer rem oval in t he root canals of ex vivo hum an
t eet h
Faustino GARCIA1, Peter E. MURRAY2, Franklin GARCIA-GODOY3, Kenneth N. NAMEROW4
DDS, Graduated resident (Endodontics), Private Practice, Formerly of the Department of Endodontics, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Florida, USA.
BSc(Hons), PhD, Professor, Department of Endodontics, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Florida, USA. DDS, MS, Professor and Executive Associate Dean for Research, College of Dentistry, University of Tennessee, Memphis, USA.
DDS, Associate Professor, Director of Postgraduate Endodontics, and Chair, Department of Endodontics, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Florida, USA.
Corresponding address: Dr. Peter E. Murray - Department of Endodontics - College of Dental Medicine - Nova Southeastern University - 3200 S. University Dr.
Fort Lauderdale - FL 33328-2018, USA - Phone (954) 262 1743 - Fax (954) 262 1782 - e-mail: petemurr@nova.edu
Received: January 16, 2009 - Modiication: September 5, 2009 - Accepted: March 14, 2010
O
bj ect ives: The pur pose of t his st udy was t o m easur e and com par e t he r oot canal cleanliness and sm ear layer r em oval effect iveness of Aquat ine Endodont ic Cleanser ( Aquat ine EC) w hen used as an endodont ic ir r igat ing solut ion in com par ison w it h 6% sodium hypochlorite (NaOCl). Material and Methods: Forty-ive human teeth were randomly allocated to ive treatment groups; the pulp chamber was accessed, cleaned, and shaped by using Pr oTaper and Pr oFile r ot ar y inst r um ent at ion t o an I SO size # 40. The t eet h w er e t hen pr ocessed for scanning elect r on m icr oscopy, and t he r oot canal cleanliness and r em oval of sm ear layer w er e exam ined. Result s: The m ost effect ive r em oval of sm ear layer occur r ed w it h Aquat ine EC and NaOCl, bot h w it h a r inse of EDTA. Conclusions: Aquat ine EC appear s to be the irst hypochlorous acid approved by the FDA to be a possible alternative to the use of NaOCl as an int racanal ir r igant . Fur t her r esear ch is needed t o ident ify safer and m or e effect ive alt er nat ives t o t he use of NaOCl ir r igat ion in endodont ics.Ke y w or ds: I r r igat ion. Dent al pulp. EDTA. Sodium hypochlor it e. Hypochlor ous acid.
for t he t reat m ent of t eet h wit h pulp necrosis19, even
t hough it has several undesirable charact er ist ics su ch as t issu e t ox icit y at h igh con cen t r at ion s,
risk of emphysema when overilling, and allergic
pot ent ial21. Mor eover, NaOCl does not t ot ally clean
t he sur faces of t he r oot canals1. These pr oblem s
suggest t hat NaOCl ir r igat ion is not fully opt im ized and t her e is a need t o ident ify ir r igant s w hich ar e effect ive, but also biocom pat ible, t o avoid t he r isk of har m ing pat ient s.
The sm ear layer is a 1- 5 m m t hick layer2 of
denat ured cut t ing debris produced on inst rum ent ed cav i t y su r f a ce s, a n d i s co m p o se d o f d e n t i n ,
odontoblastic processes, non-speciic inorganic
cont am inant s and m icroorganism s5. The rem oval of
sm ear layer fr om t he inst r um ent ed root canal walls is cont roversial17. I t s rem oval provides bet t er sealing ability of the endodontic illing material to dentin,
int o oral t issues m ust be pr event ed because it is believed t hese oft en cause com plicat ions leading t o t r eat m ent failur e.
Th e d isin f ect ion of r oot can als t h r ou g h t h e elim inat ion of m icr oor ganism s is an essent ial st ep in endodont ic t r eat m ent3 t o help avoid subsequent
failur e10. Sur face adher ence by bact er ia t o for m bioilms is a good example of bacterial adaptation
and one t hat is per t inent t o endodont ic infect ions. I n cr easin g in f or m at ion is n ow available on t h e
existence of bioilm communities on root canal
w alls2 8. Un f or t u n at ely, com p let e d isin f ect ion is dificult to accomplish; microorganisms can remain
w it hin t he apical dent in plug15, w it hin t he sm ear
layer8 and wit hin t he dent inal t ubules18. To m axim ize
t he r em oval of m icr oor ganism s, t he shaping and m echanical enlar gem ent of a r oot canal m ust be accom panied by copious ir r igat ion10,13. The ideal
ir r igant should have an ant im icr obial act ion, low t oxicit y and good biocom pat ibilit y t o oral t issues. I n addit ion, it should have t he capacit y t o clean t he walls of t he r oot canal and r em ove t he sm ear layer.
I n Au g u st 2 0 0 6 , t h e U. S. Fo o d a n d D r u g Adm inist rat ion clear ed St er ilox Dent al’s Aquat ine En d o d o n t i c Cl e a n se r ( Aq u a t i n e EC, St e r i l o x Puricore, Malvern, PA, USA) for use as an endodont ic ir r ig at in g solu t ion . Aq u at in e EC is in t en d ed t o ir r igat e, cleanse and debr ide t he r oot canal syst em ( 510k num ber K061689) . The act ive com ponent in Aquat ine EC is hypochlor ous acid ( HOCl) . HOCl is pr odu ced by t h e body ’s im m u n e cells, v ia a ch ain of aer obic r eact ion s called t h e Ox idat iv e Bur st Pat hway, t o kill invading pat hogens and t o
ight infection6. St er ilox Pu r icor e ( Malv er n , PA,
USA) has developed a range of m edical pr oduct s t hat cont ain differ ent concent rat ions of HOCl. The HOCl solu t ion is pr odu ced by elect r och em ically char ging a low concent rat ion salt solut ion using an elem ent react or. HOCl is com m only used for hospit al disinfect ion, st er ilizat ion, and in t he t r eat m ent of chronic wounds22,25. I n dent ist ry it is com m only used to disinfect water lines by removing bioilms7,12.
HOCl is biocom pat ible and ant im icr obial against a br oad range of m icr oor ganism s12. A pilot st udy of
t he cleaning effect iveness of an elect r ochem ically act ivat ed solut ion ( EAS) t hat cont ained a m ixt ur e of HOCl, ClO-, ClO and H
2O2 at pH 7.7 found it s
sm ear layer r em oval effect iveness was super ior t o 3% NaOCl27. How ever, t her e have been no st udies
t o dat e exam ining t he effect iveness of Aquat ine EC as an endodont ic ir r igant .
Th e obj ect iv e of t h is st u dy w as t o evalu at e Aquat ine EC as an endodont ic ir r igat ing solut ion in a sim ulat ed clinical set t ing w here bact erial invasion of t he dent al t ubules occur s pr ior t o biom echanical in st r u m en t at ion . Th e clean in g ef f ect iv en ess of
Aquatine EC to remove bacterial bioilm, debris
and sm ear layer fr om r oot canals was assessed by
visualizat ion, using scanning elect r on m icr oscopy.
M ATERI AL AN D M ETH OD S
A pr e- exist ing ar chive of ext ract ed hum an t eet h was used for t his st udy following inst it ut ional review boar d appr oval. Th e in t act , r an dom ly select ed, per m anent t eet h had not pr eviously r eceived any r oot canal m edicam ent s nor w er e any st or ed in
antibacterial or ixative solutions. The teeth were
X- rayed pr ior t o inclusion in t his pr oj ect t o ensur e t hat all t he t eet h had a single r oot canal, and t he r oot lengt hs w er e appr oxim at ely 18 m m . The t eet h w er e de- cr ow ned at t he cem ent oenam el j unct ion using a diam ond rot ary bone- cut t ing saw ( Mat erials Science, NW Lt d, Set t le, England, UK) . Each t oot h
was placed in an eppendorf tube and illed with
brain hear t infusion br ot h ( BHI , Difco Laborat or ies, Det r oit , MI , USA) .
Pu r e cu lt u r e E. f aecalis ( ATCC 2 9 2 1 2 , PML Microbiologicals, Wilsonville, OR, USA) grown in BHI brot h ( Difco Laborat ories) was used t o cont am inat e t he eppendorf t ubes cont aining t he ext ract ed t eet h. Each individual t oot h was inoculat ed w it h 10 m L of a 1.5x108 CFU m L- 1 suspension using a st er ile
1 m L using a t uber culin syr inge. The t eet h w er e incubat ed in a 5% CO2 at m ospher e at 37oC for 28
days4,24. Dur ing t he 28 day infect ion per iod, t he
BHI m edia was r efr eshed ever y t hir d day t o ensur e bact er ial viabilit y. Aft er 28 days of in vit r o cult ur e in t h e pr esen ce of E. f aecalis, t h e absor ban ce of t he BHI cult ur e m edia was m easur ed at 600 nm t o ensur e t hat all ( 100% ) of t he t eet h w er e cont am inat ed20 prior t o t he shaping and cleaning of
r oot canals. At 28 days, t he ext er nal and int er nal sur faces of each t oot h w er e sam pled w it h st er ile
ine paper points and inoculated on BHI agar plates to conirm infection of the specimens. E. faecalis in pur e cult ur e was det er m ined by visualizat ion of individual w hit e pinpoint colonies on t he BHI agar
plates. Conirmation was determined by microscopic
o b se r v a t i o n o f Gr a m - p o si t i v e co cci a r r a n g e d in a cr oss- chain pat t er n, follow ing t he pr ot ocol descr ibed by Shabahang and Torabinej ad24 ( 2003) .
Th e t eet h w er e in st r u m en t ed w it h Pr oTaper ( Dent sply Tulsa Dent al, Oklahom a Cit y, OK, USA) f ile ser ies t o F3 , an d t h e can als w er e f u r t h er
enlarged with Proiles (Dentsply, Tulsa Dental)
35/ .06 and 40/ .06 sim ilar t o t he m et hods described b y Sh ab ah an g an d To r ab i n ej ad2 4 ( 2 0 0 3 ) , an d
Cr um pt on, Goodell and McClanahan4 ( 2005) . The
working lengt h was det erm ined by passively placing
a #10 K-ile (Dentsply Tulsa Dental) in the canal
of irrigat ing solut ion was used wit h each inst rum ent size. I n each canal dur ing inst r um ent at ion, a t ot al v olu m e of 2 5 - 3 0 m L of ir r igat ion solu t ion w as deliv er ed using sm all plast ic needles ( Ult radent Pr oduct s, Sout h Jor dan, UT, USA) . The follow ing ir r igat ion pr ocedur es w er e used: gr oup i) Cont r ol gr oup: The canals of 5 inst r um ent ed t eet h w er e ir r igat ed w it h dist illed wat er t o ser ve as negat ive con t r ols. Th e r em ain in g 4 0 t eet h w er e div ided int o 4 exper im ent al gr oups of 10 t eet h per gr oup: gr oup ii) , t he r oot canals w er e ir r igat ed dur ing inst r um ent at ion w it h Aquat ine EC solut ion. The Aqu at in e EC hy poch lor ou s acid ( HOCl) solu t ion ( 180- 250 ppm of available fr ee chlor ine ( AFC) , pH 5 . 3 5 - 6 . 7 5 ) w as pr epar ed fr esh, by elect r oly sis, im m ediat ely pr ior t o u se. Th e con cen t r at ion of ( AFC) was m easur ed phot om et r ically follow ing t he
acidiication of the Hypochlorous acid [HOCl] to
Chlor ine [ Cl-] ( Palint est I nc., KY, US) . Gr oup iii) ,
t he r oot canals w er e ir r igat ed w it h Aquat ine EC solut ion as descr ibed in gr oup ii) , follow ed by t he applicat ion of 2 m L of 17% EDTA for 15 s26. Gr oup
iv) , t he r oot canals w er e ir r igat ed w it h 6% NaOCl ( Clor ox, Oakland, CA, USA) . I n gr oup v) , t he r oot canals w er e ir r igat ed w it h 6% NaOCl follow ed by t he applicat ion of 2 m L of 17% EDTA ( PulpDent , Wat er t ow n , MA, US) f or 1 5 s. Th ese m et h od s w er e con g r u en t w it h t h ose of Sh ab ah an g an d Torabinej ad24 ( 2003) .
The effect iveness of t he ir r igat ion t r eat m ent s t o clean t h e r oot can als w er e assessed u sin g m icr ograph im ages of t he r oot canals collect ed using a scanning elect r on m icr oscope ( SEM) . The
teeth were prepared for use in the SEM by ixing
t he t oot h t issues in 10% neut ral- buffer ed for m alin solut ion at 18°C for 24 h. The t eet h were t hen post
-ixed in osmium tetroxide (1% w/v) for 2 h before
being dehy drat ed in a graded ser ies of et hanol
solutions. The teeth were dried on ilter paper for
24 h and t hen fract ur ed longit udinally along t he lengt h of t he canal using a chisel. Each t oot h- half was m ount ed ont o alum inum st ereoscan st ubs wit h carbon t ape ( Ted Pella I nc., Redding, CA, USA) w it h t he ent ire lengt h of t he root canal visible and facing upwar ds. Each of t he specim ens was coat ed w it h a 20- 30 nm t hin m et allic layer of gold/ palladium in a Polar on E5000 sput t er coat er ( BioRad, Her cules, CA, USA) . The sam ples were viewed in a Quint a 200 SEM ( FEI , Hilsbor o, OR, USA) . SEM m icr ographs
were obtained at x2,000 magniication using digital
im age analysis soft war e. Each of t he r oot canals was scanned in it s ent ir et y t o obt ain an over view of t he general sur face t opography24. Micr ographs
were t aken of represent at ive areas charact erist ic of t he general sur face t opography of each specim en, including t he apical, m iddle and cor onal aspect s14.
The dent in r oot canal sur faces w er e assessed for t he pr esence of sm ear layer by t w o double- blind r ev iew er s using sem i- quant it at ive v isual cr it er ia descr ibed by Cr um pt on, Goodell and McClanahan4
( 2005) , Madison and Hoket t11 ( 1997) and Tay, et
al.29 ( 2006) using a 4- st ep scale: ( 0) All t ubules
visible. ( 1) Mor e t han 50% of t ubules visible. ( 2) Less t han 50% of t ubules visible, and ( 3) No t ubules visible. The r em oval of sm ear layer fr om t he r oot canals was analyzed using Chi- Square (c2) st at ist ics
t est s ( St at view, SPSS, Car y, NC, USA) .
RESULTS
Aft er 28 days of in vit r o cult ur e in t he pr esence of E. faecalis, t he absor bance count s fr om t he BHI
Figure 1- Scanning Electron Microscopy (SEM) micrograph
of a root canal irrigated with Aquatine EC and a rinse of EDTA. All dentinal tubules are visible and the smear layer was completely removed
Figure 2- Scanning Electron Microscopy (SEM) micrograph
cult ur e m edia of each t oot h gave high absor bance count s at 600 nm , indicat ing t hat all ( 100% ) of t he t eet h w er e cont am inat ed20 pr ior t o t he shaping and
cleaning of r oot canals.
The available fr ee chlor ine ( AFC) concent rat ion of t he Aquat ine EC was t est ed pr ior t o each use, by m easur ing t he hypochlor ous acid cont ent ; it was st ably pr oduced by elect r oly sis ( St er ilox Dent al, Malver n, PA, USA) at a concent rat ion of 180- 200 ppm AFC, pH 6.0.
Analysis of t he sm ear layer r em oval dat a for differ ences bet w een t he cor onal, m iddle and apical
aspect of teeth found no signiicant differences (c2, p>0.05). Therefore, the data was not stratiied
accor ding t o t he differ ent aspect s of t eet h pr ior t o
fur t her st at ist ical analysis.
Th e r em oval of sm ear lay er cov er in g den t al
tubules was inluenced by the use of different
i r r i g a t i o n t r ea t m en t s (c2, p < 0 . 0 5 ) . Th e m o st
com plet e r em oval ( 100% ) of sm ear layer cover ing r oot canal dent inal t ubules was obser ved follow ing root canal irrigat ion w it h Aquat ine EC and a rinse of EDTA ( Figur e 1) . The least r em oval of sm ear layer cover ing r oot canal dent inal t ubules was obser ved follow ing ir r igat ion w it h dist illed wat er ( Figur e 2) w hich was a cont r ol gr oup. Aquat ine EC and EDTA com plet ely r em oved t he sm ear layer in 30% of t eet h, and rem oved m ore t han half t he sm ear layer in a fur t her 30% of t eet h ( Figur e 3) . NaOCl and EDTA ( Figur e 4) com plet ely r em oved 26.7% of t he
Figure 3- Presence of smear layer in root canals following root canal irrigation treatments. The presence of smear layer
criterion is shown as a percentage of root canals for each of the irrigation treatments
Figure 4- Scanning Electron Microscopy (SEM) micrograph
of the smear layer in root canals irrigated with NaOCl and a rinse of EDTA. All dentinal tubules are visible and the smear layer was completely removed
Figure 5- Scanning Electron Microscopy (SEM) micrograph
sm ear layer cover ing dent inal t ubules, and m or e t han half t he sm ear layer cover ing t he dent inal t ubules in a fur t her 13. 3% of t eet h ( Figur e 3) . Alt hough t here were m ore dent inal t ubules covered w it h sm ear layer follow ing NaOCl ir r igat ion w it h a r inse of EDTA ( Figur e 3) , t her e was lit t le differ ence in com par ison w it h Aquat ine EC follow ed by a r inse of EDTA (c2, p> 0. 05) . The gr eat est pr esence of
sm ear layer was observed covering dent inal t ubules in t he root canals irrigat ed wit h Aquat ine EC ( Figure 5) and NaOCl ( Figur e 6) w it hout EDTA ( Figur e 3) , w hich w er e cont r ol gr oups.
D I SCUSSI ON
The r em oval of sm ear layer fr om r oot canals ap p ear ed t o b e in f lu en ced b y t h e select ion of endodont ic ir r igant s and t he use of EDTA dur ing r oot can al in st r u m en t at ion . A pr ev iou s in v it r o st udy has dem onst rat ed t he effect iveness of HOCl
to disinfectant mixed species bioilms30, and t hat
it has ex cellent biocom pat ibilit y t o t issues. The biocom pat ibilit y and safet y of Aquat ine EC have ear ned it FDA clearance as a m edical device in lat e 2006 t o be sold and m ar ket ed as an endodont ic ir r igant . This pr oduct is new, and it has not been pr eviously t est ed as an endodont ic ir r igant . Only one pr evious pilot st udy of 20 t eet h by Solovyeva and Dum m er27 ( 2000) has been published about t he
cleaning effect iveness of a pH 7.7 EAS cont aining a m ixt ur e of biological r eagent s including HOCl. That st udy, obser ved t he EAS in com par ison t o NaOCl, rem oved m ore sm ear layer and m ore debris, leaving
cleaner canals. Because of these beneicial results,
Solovyeva and Dum m er27 ( 2000) have advocat ed
EAS t o be used as an alt er nat ive t o NaOCl, but no
fur t her pr ogr ess t o advance t he int r oduct ion of EAS int o endodont ic pract ice appear s t o have been m ade, unt il now.
NaOCl is recom m ended for use as an endodont ic irrigant by t he Am erican Associat ion of Endodont ist s, but it is not approved by t he FDA because of it s high t oxicit y, caust ic hazar d, r isk of em physem a in case
of overilling, and the severe allergic reactions that
can result in pat ient suffering21. The widespread use
of NaOCl as an endodont ic irrigat ing solut ion can be explained by it s low pr ice, excellent necr ot ic pulp t issue dissolut ion pr oper t ies, and it s excellent r oot canal disinfect ion pr oper t ies. Since NaOCl is t he endodont ic “ gold st andar d”, exper im ent al ir r igant s m ust be com par ed w it h it , t o be able t o com par e sm ear lay er r em oval. Th e com par ison bet w een NaOCl and Aquat ine EC in t his pr esent st udy found t hat w hen bot h ar e used w it h a r inse of EDTA; t hey ar e sim ilar ly effect ive at r em oving debr is and cleaning r oot canals, and r em ov ing sm ear layer cover ing dent al t ubules and also inside t he dent al t ubules.
I n t h e p r esen t st u d y, t h e r oot can als w er e cont am inat ed w it h E. faecalis t o allow for ease of m aint enance and ident ify ing t he gr ow t h of a single species. A 28- day infect ion per iod allow ed
for bioilm growth and the penetration of bacteria
int o t he dent inal t ubules24. The m icr obial sam pling
d e m o n st r a t e d t h a t b a ct e r i a r e m a i n e d v i a b l e t hroughout t he experim ent . Most st udies of bact erial gr ow t h fr om r oot canals have visualized t ur bidit y in t he cult ur e m edia as t he end point . I n or der t o avoid subj ect ivit y in det er m ining t ur bidit y, visual assessm ent w e used, and t he absor bance of t he BHI cult ur e was m easur ed in a spect r ophot om et er.
The presence of sm ear layer prevent s penet rat ion of ant ibact er ial agent s int o t he dent inal t ubules,
indicating that its removal may beneit disinfection
and also sealing and adhesion of endodont ic sealers t o root canal walls29. The previous pilot st udy of EAS
dem onst rat ed it s abilit y t o par t ially r em ove sm ear layer in t he absence of a chelat ing agent27. The
pr esent r esult s ar e som ew hat in agr eem ent , but showed t hat sm ear layer rem oval was m ore opt im al in t he Aquat ine EC t eet h w it h a r inse of 17% EDTA, com par ed t o t eet h inst r um ent ed w it hout EDTA. I n t he absence of a r inse of EDTA, t he Aquat ine EC was not ver y effect ive at cleaning r oot canals or r em oving sm ear layer, indicat ing t hat for opt im al p er f or m an ce, Aq u at in e EC m u st b e u sed w it h a r inse of EDTA. I t is unlikely t hat t he lengt h of t im e, or quant it y of EDTA used for ir r igat ion causes m arked differences bet ween different st udies30. This
indicat es t hat any differ ences obser ved in sm ear layer rem oval are caused by t he difference bet ween t he EAS in t he pilot st udy27 and t his pr esent st udy.
The pot ency of t he Aquat ine EC was t est ed pr ior t o each use, by m easur ing t he HOCl cont ent ; it
Figure 6- Scanning Electron Microscopy (SEM) micrograph
was st ably pr oduced by t he elect r olysis unit at a concent rat ion of 180- 200 ppm AFC, pH 6.0. I n t he pilot st udy t he anoly t e neut ral cat hodic solut ion had an act ive chlor ine concent rat ion of 300 m gL -1. I ndicat ing t hat t he EAS was slight ly differ ent in
com posit ion t o Aquat ine EC and likely was m or e p ot en t . Th is d if f er en ce ser v es t o d em on st r at e t hat bot h EAS and Aquat ine EC m ay be able t o r em ove sm ear layer w it hout chelat ing agent s if t he concent rat ion of hypochlor ous acid is incr eased.
CON CLUSI ON S
On t he basis of t hese r esult s, it appear s t hat Aquat ine EC has a sim ilar effect iveness as NaOCl w hen used w it h a r inse of EDTA t o clean r oot canals of debr is an d t o r em ov e sm ear lay er follow in g con t am in at ion w it h E. f aecalis. Th e clean lin ess of t he r oot canals and t he degr ee of sm ear layer r em oval w er e com parable w it h t hat of 6% NaOCl. Aquat ine EC m ay be super ior t o NaOCl in t er m s of safeguar ding pat ient s fr om accident s because it is a biocom pat ible root canal cleanser, whereas NaOCl is not . Aquat ine EC could t her efor e pr ovide a safer alt er nat ive t o NaOCl disinfect ion for t he r em oval
of bioilm bacteria in endodontic canals. Further
st udies ar e needed t o det er m ine t he effect of t hese
indings in clinical settings.
ACKN OW LED GEM EN TS
This st udy was support ed by Nova Sout heast ern Universit y and PuriCore St erilox, Malvern, PA, USA.
REFEREN CES
1- Baum gar t ner JC, Mader CL. A scanning elect r on m icr oscope ev al u at i o n o f f o u r r o o t can al i r r i g at i o n r eg i m es. J En d o d . 1987; 13: 147- 57.
2- Br ännst r öm M, Nor denvall KJ, Glanz PO. The effect of EDTA-cont aining surface- act ive solut ions on t he m orphology of prepared dent in: an in vivo st udy. J Dent Res. 1980; 59: 1127- 31. 3- Byst r om A, Happonen RP, Sj ogr en U, Sundqvist G. Healing of per iapical lesions of pulpless t eet h aft er endodont ic t r eat m ent w it h cont r olled asepsis. Endod Dent Traum at ol. 1987; 3: 58- 63. 4- Cr um pt on BJ, Goodell GG, McClanahan SB. Effect s on sm ear layer and debr is r em oval w it h var ying volum es of 17% REDTA aft er r ot ar y inst r um ent at ion. J Endod. 2005; 31: 536- 8
5- Czonst kow sy M, Wilson EG, Holst ein FA. The sm ear layer in endodont ics. Dent Clin Nor t h Am . 1990; 34: 13- 25.
6- Fang YZ, Yang S, Wu G. Free radicals, antioxidants, and
nut r it ion. Nut r it ion. 2002; 18: 872- 9.
7- Fukuzaki S. Mechanism s of act ions of sodium hypochlor it e in cleaning and disinfect ion processes. Biocont rol Sci. 2006; 11: 147-57.
8- Huque J, Kot a K, Yam aga M, I waku M, Hoshino E. Bact er ial eradicat ion fr om r oot dent ine by ult rasonic ir r igat ion w it h sodium hypochlor it e. I nt Endod J. 1998; 31: 242- 50.
9- Jeansonne M, Whit e RR. A com par ison of 2.0% chlor hexidine g lu con at e an d 5 . 2 5 % sod iu m h y p och lor it e as an t im icr ob ial endodont ic ir r igant s. J Endod. 1994; 20: 276- 8.
10- Lin LM, Sk r ibner JE, Gaengler P. Fact or s associat ed w it h endodont ic t r eat m ent failur es. J Endod. 1992; 18: 625- 7. 11- Madison JG 3rd, Hoket t SD. The effect s of different t et racyclines on t he dent in root surface of inst rum ent ed, periodont ally involved hum an t eet h: a com parat ive scanning elect r on m icr oscope st udy. J Per iodont ol. 1997; 68: 739- 45.
12- Martin MV, Gallagher MA. An investigation of the eficacy of
super- oxidised ( Opt ident / St er ilox) wat er for t he disinfect ion of dent al unit wat er lines. Br it Dent J. 2005; 198: 353- 4.
13- Molander A, Reit C, Dahlén G, Kvist T. Microbiological st at us of
root-illed teeth with apical periodontitis. Int Endod J. 1998;31:1-7.
14- Mur ray PE, Far ber RM, Nam er ow KN, Kut t ler S, Gar cia- Godoy F. Evaluat ion of Mor inda cit r ifolia as an endodont ic ir r igant . J Endod. 2008; 34: 66- 70.
15- Nair PN, Sj ogr en U, Kr ey G, Kahnber g KE, Sundqv ist G.
Intraradicular bacteria and fungi in root-illed, asymptomatic
hum an t eet h w it h t herapy- r esist ant per iapical lesions: a long-t er m lighlong-t and eleclong-t r on m icr oscopic follow- up slong-t udy. J Endod. 1990; 16: 580- 8.
16- Or st avik D, Pit t For d TR. Essent ial endodont ology. Pr event ion and t r eat m ent of apical per iodont it is. Oxfor d: Blackw ell Science; 1998.
1 7 - Pash ley DH. Sm ear lay er : an ov er v iew of st r u ct u r e an d funct ion. Pr oc Finn Dent Soc. 1992; 88( Suppl 1) : 215- S24. 18- Pet er s LB, Wesselink PR, Moor er WR. The fat e and t he r ole of bact er ia left in r oot dent inal t ubules. I nt Endod J. 1995; 28: 95- 9. 1 9 - Qu alt r ou g h AJ, Wh it w or t h JM, Du m m er PM. Pr eclin ical en d od on t ol og y : an i n t er n at i on al com p ar i son . I n t En d od J. 1999; 32: 406- 14.
20- Robert s A, Mat t hews JB, Socransky SS, Freest one PP, William s PH, Chapple I L. St r ess and t he per iodont al diseases: effect s of cat echolam ines on t he growt h of periodont al bact eria in vit ro. Oral Micr obiol I m m unol. 2002; 17: 296- 303.
2 1 - Se g u r a JJ, Ji m e n e z- Ru b i o A, Gu e r r e r o JM, Ca l v o JR. Com parat ive effect s of t w o endodont ic ir r igant s, chlor hexidine digluconat e and sodium hypochlor it e on m acr ophage adhesion t o plast ic sur face. J Endod. 1999; 25: 243- 6.
22- Selkon JB, Cher r y GW, Wilson JM, Hughes MA. Evaluat ion of hypochlor ous acid washes in t he t r eat m ent of chr onic venous leg ulcer s. J Wound Car e. 2006; 15: 33- 7
2 3 - Sen BH, Wesselin k PR, Tü r k ü n M. Th e sm ear lay er : a phenom enon in r oot canal t herapy. I nt Endod J. 1995; 28; 141- 8. 24- Shabahang S, Torabinej ad M. Effect of MTAD on Ent er ococcus
faecalis- cont am inat ed r oot canals of ext ract ed hum an t eet h. J
Endod. 2003; 29: 576- 9.
25- Shet t y NS, Sr inivasan J, Holt on, Ridgway GL. Evaluat ion of m icr obiocidal act ivit y of a new disinfect ant : St er ilox 2500 against
Clostridium dificile spor es, Helicobact er py lor i, van com y cin -r esist ant Ent e-r ococcus species, Candida albicans and sev e-ral
Mycobact er ium species. J Hosp I nfect . 1999; 41: 101- 5.
26- Siqueira JF Jr, Machado AG, Silveira RM, Lopes HP, Uzeda M. Evaluat ion of t he effect iveness of sodium hypochlor it e used w it h t hree irrigat ion m et hods in t he elim inat ion of Ent erococcus faecalis fr om t he r oot canal, in vit r o. I nt Endod J. 1997; 30: 279- 82. 27- Solovyeva AM, Dum m er PM. Cleaning effect iveness of r oot can al ir r igat ion w it h elect r och em ically act ivat ed an oly t e an d cat holyt e solut ions: a pilot st udy. I nt Endod J. 2000; 33: 494- 504. 28- Takem ura N, Noir i Y, Ehara A, Kawahara T, Noguchi N, Ebisu
S. Single species bioilm-forming ability of root canal isolates on
gut t a- per cha point s. Eur J Oral Sci. 2004; 112: 523- 9.
2 9 - Tay FR, Pash ley DH, Lou sh in e RJ, Doy le MD, Gillesp ie WT, Weller RN, et al. Ult r ast r u ct u r e of sm ear lay er - cov er ed int raradicular dent in aft er ir r igat ion w it h BioPur e MTAD. J Endod. 2006; 32: 218- 21.
30- Walker JT, Bradshaw DJ, Fulford MR, Marsh PD. Microbiological evaluat ion of a range of disinfect ant pr oduct s t o cont r ol m
ixed-species bioilm contamination in a laboratory model of a dental
