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52 Ho ng Kong Den t J Vol 1 No 2 July 2004

HKDJJJJJ

FEATURED ARTICLEHong Kong Dental Journal 2004;1:52-7

Introduction

Bacteria were first implicated in the causation of pulpaland p eriradicular diseases by van Leeuwenhoek in the 17thcentury 1. Since then, studies have confirmed and elucidat-ed the role of bacteria in the etiology of these diseases 2-7.Other microbiologic studies h ave suggested that thepresence of intraradicular bacteria is an important factoraffecting the success rate of endodontic treatment 8,9. Onthe basis of the evidence available, preserving the sterilityor sterilization of the root canal system will increase thelikelihood of success of roo t canal treatment. To maintaina sterile root canal system, asepsis should be observedduring endodontic treatment and p rovision of the definitive

coronal restoration. When treating an infected root canal,the process of cleaning and shaping could be viewed as akey step of root canal treatment 10.

The root canal system is complex and accessory fea-tures, such as fins, cul de sacs, and intercanal communica-tions 11,12, are colonized by microorganisms once the toothbecomes infected. Bacteria have also been iden tified indentinal tubules, halfway through the root dentine ofinfected teeth 13. Nair 14 reported seeing mainly looseclumps of bacteria suspen ded in the canal lumen afterexamining the root canal flora under transmissionelectron microscopy. Self-aggregates of monobacterialmorphotypes and coaggregates of different bacterial

morpho types were also found adhering to teeth. Theinterbacterial spaces were occupied by an amorphous

material, spirochetes, and hyphal-like structures thatwere suggestive of fungi 14. Costerton et al15 used theterm biofilm to describe this clustering of bacteria.Bacteria within a b iofilm have increased re sistance toa variety of external ho stile influen ces, such as the hostdefense responses, antibiotics, antiseptics, and shearforces, compared with isolated bacterial cells 16. Oncebacteria have established themselves in the root canalsystem, they are difficult to eradicate by chemical ormechanical means. Furthermore, den tine can reduce theantimicrobial properties of irrigating and intracanalsolutions 17,18.

Miller 1 stated that there was a large diversity of endo-don tic microflora, but n ot all of them could be detectedby culturing. Using culture techniques, Sundqvist 6

recovered up to 12 different strains of bacteria fromeach infected roo t canal, whereas Fabricius 7 recoveredbetween 8 and 15 strains in primates. The use of moleculartechniques in microbial iden tification has allowed moremicroorganisms to be de tected, such as spirochetes 19 andother uncultivable species 20,21. The mean number of taxarecovered per sample using a combination of cultural andmolecular analyses was approximately 20.

Certain bacteria, such as Enterococcus faecalis, andcertain fungi, such as Candida albicans, have been shownto be resistant to antibiotics 22 and to commonly used rootcanal medicaments, such as calcium hydroxide 23-25. Thesemicroorganisms can survive in root canals after seeminglyadequate cleaning and shaping, and both E faecalis26,27

and C albicans28 have been associated with the failure ofroot canal treatment. Although other resistant organismsmight be present in root canals, they would not beidentifiable by culturing.

Assistant Pro fessor in Conservative Den tistry, Faculty of Den tistry,The University of Hong Kong, Prince Philip Dental Hospital,34 Hospital Road, Hong Kong

Correspondence to:Dr. Robert Pon g-Yin NgTel : 2859 0287Fax : 2559 9013e-mail : [email protected]

Sterilization in roo t canal treatmen t:curren t advances

Robert Pong-Yin Ng, BDS, MSc, MClinDent, MRD RCSEd, Adv Dip Endodont, FRACDS, LDS RCSEng

ABSTRACT Sterilization of root canal is an important step in the treatment to prevent the development of or toresolve any periradicular pathology. Conventionally, mechanical and chemical means have been used to clean the rootcanal systems. Various novel agents or techno logies have been recently available to supplemen t or replace the currentmethods of root canal debridement. This article reviews some of these emerging technologies and assesses theirefficacy.

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Sterilization in root canal treatm ent

Ho ng Kong Dent J Vol 1 No 2 July 2004 53

A combination o f mechanical cleaning an d che micaldisinfection is commonly used to prep are root canals;however, infected root canals are not always sterilizedusing these methods 9. This article introduces some o f therecent develop ments in the identification of new agentsor technologies to sterilize infected root canals. These

developments can be divided into three groups: irrigatingsolutions, root canal preparation techniques, andadjunctive therap y.

Irrigating s olutions

Irrigants are used during root canal preparation to helplubricate canal walls, soften d entine, remove deb ris andsmear layer, dissolve organic matter, kill microorganisms,and clean areas inaccessible to endodontic instruments 29.Sodium h ypochlorite so lution has many of these desiredprop erties and is widely used as an irrigant in a range o f

concentrations30

. This irrigant, howe ver, is toxic to thehost and, if acciden tally extruded into periradicular areas,it can cause acute pain, extensive destruction of tissues,and severe inflammation 31.

Electrochemically activated (ECA) water has been foundto be biocompatible and effective in wound cleansing 32.Two types of ECA solutions can be produced from tapwater and a saline solution using a flow-through electrolyticmodule 32. The first is an anolyte that has antimicrobialprop erties, a high oxidation po tential, and a pH valueranging from 2 to 9. The other is a catholyte that acts like adetergent, has a high reduction potential, and is alkaline.

Electrochemically activated water exists in a metastablestate that contains a variety of free radicals, molecules, andions. Biocidal agents, such as hydrogen peroxide, sod iumhydroxide, and ozone, are also present in ECA water.After 48 hours, the solution will return to a stable inactivestate. Marais and Brzel 33 showed that using ECA in den talunit water lines could effectively eliminate biofilms andcontro l bacterial counts. Electrochemically activated wateris more effective than sodium hypochlorite solution insmear layer removal 32. Nevertheless, when the anolyteand catholyte were used individually to irrigate infectedroot canals, results of antimicrobial effectiveness tests

were d isappoint ing compared wi th 3 .5% sodiumhypochlorite 34.

A group of Japanese researchers have evaluated asolution called electrolyzed neutral water, which isproduced by a proprietary electrolysis machine. Thissolution has a pH close to 7 and possesses somebactericidal or growth-inhibitory effect against a selectionof endodontic pathogens in vitro 35. Other researchers haveevaluated an ECA solution termed oxidative p otentialwater 36, which is claimed to be highly antimicrobial

because of its acidity and high oxidation-reductionpotential. This solution has been reported to efficientlyremove the smear layer and debris when it is used to irrigatethe root canal 37. Both electrolyzed neutral water andoxidative potential water are claimed to be harmless tohumans 35,37 and are probably similar to ECA water. Another

group of researchers have also found ECA anolyte andcatholyte to be effective in removing the smear layer anddebris from the root canals 38.

A recently introduced irriganta mixture o f tetracyc-line, acetic acid, and Tween 80 detergent (MTAD)wasdesigned to be used as a final root canal rinse beforeobturation 39. It seems that MTAD has some advantagesover conventional irrigants and solutions used in rootcanal treatment. For example, MTAD is effective inremoving the smear layer along the who le length of theroot canal 40 and in removing organic and inorganic

debris

41

, and did not produce any signs of erosion orphysical changes in den tine 42, whereas a mixture of5.25% sodium hypo chlorite an d 17% ethylenediaminetetraacetic acid (EDTA) did 39. In particular, MTAD mixtureis effective against E faecalis 43-45, and it is also lesscytotoxic than a range of endodontic medicaments,including eugenol, hydrogen peroxide (3%), EDTA, andcalcium hydroxide paste 46. The p hysical prope rties ofdentine are no t affected when MTAD is used for 5 minutes,as recommended by the clinical protocol. In contrast,sodium h ypochlorite and EDTA have be en shown toadversely affect the strength of dentine in vitro 47-49. Furtherindependent studies on MTAD are needed to confirm its

properties.

Root canal preparation techniques

Removing debris and microorganisms from the roo t canalsystems is an important step in treatment. Conventionally,this has been performed either mechanically by endodonticfiles using different techniques, or chemically by a rangeof irrigants and intracanal solutions. Complete sterilizationhas been difficult to achieve 50-52, especially in the apicalareas.

The no ninstrumentation technique (NIT), introducedin the past decade 53, is a novel method of root canaldebridement that uses the principle of controlled cavitation.The access cavity and root canal system are sealed offunde r reduced atmospheric pressure using specializedequ ipmen t. Rapidly alternating p ressure fields (30-90 MPa,25 Hz) are then generated, resulting in the p roduction ofmacroscopic and microscopic cavitation bubbles(diameter, 5-50 m) within the sodium hypochloriteirrigant 54. The vapor-filled bubbles then collapse, the rebycreating hydrodynamic turbulence 53. Extrusion of irrigant

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is avoided b ecause the p ressure of the entire system isbelow atmosph eric p ressure 53. With a vacuum-fillingmethod (using the same machine), the root canals can bedried and filled with a sealant 54. Nevertheless, NIT cannotenlarge the canal or remove the infected dentine 55.

Similar in vitro resu lts have been obtained with NITand with the conventional step-back technique of lateralcondensation 54. A second generation NIT machinehas achieved superior root canal debridement 56 an dobturation 57 results in vitro. The quality of root fillingsperformed by the second generation NIT are equivalentto that of conventional mechanical obturation, as detectedby radiography 58. The proportion of filled root canal wassimilar when comparing NIT and sealer with handinstrumen tation and warm vertical compaction o f gutta-percha 59. Attin et al60 showed that there was more debrisin the ap ical region of the roo t canal when NIT was used

in vivo than when conventional methods were used.Furthermo re, it was hypothe sized that und er clinicalconditions, the efficacy of NIT might be reduced; thus,other problems should be resolved before NIT can be usedclinically 60.

The use of lasers for various end odontic applicationshas b een investigated since 1971 61. Different types oflasers have been investigated for their efficacy in rootcanal shaping and sterilization; removal of the smearlayer and debris; and sealing of dentinal tubules in theroot canal wall. Lasers using carbon dioxide or kryp-ton fluoride have b een assessed, as have those using

yttrium-aluminum-garnet (YAG)for example, in com-bination with neodymium (Nd:YAG); ho lmium (Ho:YAG);erbium (Er:YAG); and erb ium with chromium-yttrium-scandium-gallium-garnet (Er,Cr:YSGG). Multipledrawbacks have prevented the widespread use of lasersin clinical endodontics. For example, the carbon dioxidelaser could not b e d elivered into the root canal systemthrough a suitable fiberoptic system, and the Nd:YAG laserwas poorly absorbed by the dentine 62. Furthermore, theexcessive heat generated by these lasers is deemed to bethe major limiting factor against clinical acceptance inendod ontic treatment 61. The American Association of

Endodon tists has warned that the heat could po tentiallydamage the per iodont ium or char the root cana ldentine 63. The magnitude of heat generated depends on anumber of variables, such as the type of laser, powersetting, mode of energy delivery, presence of waterspray, and the type of target tissue 62. Excimer lasers,including the k rypton fluoride laser, generate very littleheat but carry the risk of genetic mutation because thewavelength of operation is close to the absorption peak ofDNA64. Erbium lasers, which emit radiation at a wavelengthsimilar to that of the absorption peak of water, have been

considered suitable in the ablation o f dentine, because theheat they produce is not too excessive 62. Both Er:YAG 65

and Nd:YAG 66 lasers have also been used to shape rootcanals. Generally, after laser irradiation, root canal wallscan be rough and uneven 61; consequently, improvementsin the fiber tip and in the delivery method are necessary.

Shoji et al67 used a water-cooled cone-shaped irradiationtip and an Er:YAG laser to enlarge simulated root canalsthat were bored into a bovine dentine block. They reportedthat the canal walls were free o f debris and smear layer.Others have reported that the temperature rise at the rootsurface is between 0C and 5C in more than 95% ofextracted teeth when a Ho:YAG laser is used to en largethe root canal 68. Nevertheless, further d evelopmen t andtesting are requ ired to determine the ideal parameters fordifferent endodontic app lications before any lasers can beused clinically 61.

A recently introduced Er,Cr:YSGG laser (Waterlase;Biolase, San Clemente [CA], US) has been claimed topossess hydrokinetic effects: according to Rizoiu et al69,hydrokinetic effects can be created from photonsinteracting with water above and at interface of the tissue,thereby removing hard tissue without thermal side-effects.It has been claimed that this laser can be used to performroot canal shaping without local anesthesia 70, becausethe infec ted pulpa l t i ssue and dent ine would beanesthetized and ablated by the laser. Furthermore, byusing a se ries of three flexible fiberoptic tips with smalldimensions (200-400 m), this laser can clean and shapethe root canal, as well as prepare it for obturation. Although

the Waterlase has been granted ap proval for use on h ardtissues (i.e. teeth) by the United States Food and DrugAdministration, only clinical reports on this product havebeen published. Further scientific research is needed onthe safety and efficacy of Waterlase.

Adjunctive therapy

Various agents or treatment modalities have been used toenhan ce the roo t canal cleaning and shaping ability ofconventional methods. Adjunctive therapy p rimarily aimsat improving the removal of viable microorganisms, the

smear layer, and deb ris from the root canal system.

Using an Nd:YAG laser, Altamura et al71 found thatsmear layer and debris removal was effective at a lowerpower level of 2 W, 100 mJ ene rgy, and 20 Hz pu lse ratethan 4 to 5 W. Indeed, Crespi et al72 found that at a certainpower se tting, the Nd:YAG laser could clear the root canalsof debris; however, it might be difficult to clean the entirecanal surface because the laser can emit radiation only ina straight line 61. The antimicrob ial effect o f the Er:YAGlaser was investigated by Stevanovic et al73, whose results

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indicated a considerable reduction of the bacterial countin the root canals. Still, the con ditions and the p eriod ofincubation might have introduced bias, and the twobacterial species tested were not common endodonticpathogens. It also seems that selecting the correct lasersetting is paramount to avoid causing any collateral damage

to the surrounding tissues 61.

Ozone has proved to be effective in treating rootcaries 74. This gas is a p owe rful oxidative agent and ahighly potent bactericidal 75. A novel ozone-delivery system(HealOzone; CurOzone USA Inc., Aurora, Canada) wasreported to cause a considerable reduction of microbialcolony forming units associated with root caries 76. It wouldbe difficult, ho wever, to sterilize the entire roo t canalsystem by the perfusion of ozone gas. For example, Hemset al77 showed that ozone gas had no e ffect onE faecalisbiofilms. Although ozone dissolved in water had some

bactericidal effect on E faecalis, this solution was no t aseffective as sodium hypochlorite 77. It has also been claimedthat ozon e d issolved in oil is antimicrobial 78, but manyquestions must be answered before this solution can playa role in clinical endodontics. For example, the fluiddynamics and surface tension of ozone o il requires furtherinvestigation to determine whether ozone can be deliveredinto the ap ical region and accessory features (includingthe lateral canals and the infected dentinal tubules). Thechemical stability of ozone oil also needs to be studiedto find out whether it can be inactivated by materialspresen t in the root canal system, including the dentine. Inaddition, it is important to establish how completely and

easily the oil can be removed from the root canal systemprior to obturation, because o il residue may adversely affectthe ob turated root canal by interacting with the gu tta-percha and sealer, or with the bonding of the newer resin-based obturation materials, such as Resilon (ResilonResearch LLC, Madison, Connecticut, US) and Epiph any(Pentron Clinical Technologies, Wallingford, Connecticut,US) 79.

In lethal photosensitization, microorganisms aresensitized by a photoactive agent that releases bactericidalradicals when stimulated by light of an ap propriate wave-

length. This technique, termed photoactivated disinfection(PAD), show s promising results for plankton ic organismsassociated with dental caries 80, periodontal disease 81, androot canal infection 82. In PAD, a photoactive agent(tolonium chloride) is app lied to the infected area andleft in situ for a short period. The agent binds to the ce llularmembrane of bacteria, which will then rupture w henactivated by a laser source emitting radiation at anappropriate wavelength (e.g. 635-nm radiation emitted bySaveDen t; Denfotex Light Systems Ltd., Inverkeithing,United Kingdom). The light is transmitted into the root

canals at the tip of a small flexible optical fiber that isattached to a disposable handpiece. The laser emits amaximum of only 100 mW and does not generate sufficientheat to harm adjacent tissues. Furthermore, toloniumchloride dye is biocompatible and will not stain dentaltissue. The data quoted by the manufacturer suggest that

this PAD system has antimicrob ial efficacy 83.

Lethal photosensitization ofStreptococcus intermediusbiofilms in root canals is unable to achieve a total kill ratewhen a combination of a helium-neon laser and toloniumchloride are used 84. In con trast, irrigation with so diumhypochlorite (3%) eliminated the entire bacterialpopulation 84. The difference could be because the opticalfiber was not p roperly introduced into the root canals,and so the light could no t transmit through the toothstructure. Thus, PAD might not be able to achieve a 100%kill rate in infected root canals that have complex anatomic

features and colonized by polymicrobial biofilms ofvarying properties 84. Still, PAD can currently be considereda useful adjunct to conventional root canal treatment.

The Endox system (Lysis S.r.I., Nova Milanese, Italy)can sterilize the root canal by emitting high-frequencyelectrical impulses. The manufacturer has claimed thatEndox could comp letely eliminate the p ulp and bacteriafrom the entire root canal system, including the lateralcanals 85. In addition, many other advantages have beenclaimedfor example, the reduced treatment time and itssafety. Endox seems to be popular among dentists inGermany, Italy, and Spain, and numerous research reports

have been published in German and Spanish, althoughonly an abstract in English is available 86. Further, accessiblescientific evidence is required before Endox can be widelyaccepted by the international dental community.

Conclusion

Many new materials and methods have recently beenintroduced to improve root canal debridement and toachieve root canal sterilization. Some of the new treatmen tmodalities have been marketed to d entists, with the claimthat it is possible to sterilize an infected root canal system

in one appo intment. In theory, these endodontic treatmentsshould be able to treat all types of cases, and the use ofintracanal agents, such as calcium h ydroxide, wo uld no tbe necessary. However, bearing in mind the complexanatomy of the root canal system and the ability ofmicroorganisms to survive under adverse conditions, itmight be p remature to believe that the total sterilization ofthe root canal system could be readily achieved. In theage of evidence-based den tistry, it is advisable to wait untilquality independent data are available to support the useof such new technologies 87.

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References

1. Miller WD. An introduction to the study of the bacterio-pathology ofthe dental pulp. Dent Cosmos 1894;36:505-28.

2. Kake hash i S, Stanley HR, Fitzgerald RJ. The effects of surgicalexposures of den tal pulps in germ-free and conventional laboratoryrats. Oral Surg Ora l Med Oral Pathol 1965;20:340-9.

3. Mller J. Microbiological examination of root canals and p eriapicaltissues of hu man teeth. Methodological studies. Odontol Tidskr 1966;74(Suppl):S1-380.

4. Torneck CD. Reaction of rat connective tissue to po lyethylene tubeimplants. I. O ral Surg Oral Med Oral Patho l 1966;21:379-87.

5. Torneck CD. Reaction of rat connective tissue to po lyethylene tubeimplants. II. Ora l Surg Oral Med Oral Patho l 1967;24:674-83.

6. Sundq vist G. Bacteriologic s tatus of necrot ic dental pulps[dissertation]. Ume, Swed en: Umea University; 1967.

7. Fabricius L. Oral bacteria and apical periodontitis. An experimentalstudy in monkeys [dissertation]. Gteberg, Sweden: University ofGteberg; 1982.

8. Engstrm B. The significance of enterococci in root canal treatment.Odo ntol Revy 1964;15:87-105.

9. Sjgren U, Figdor D, Persson S, Sund qvist G. Influence of infection

at the time of root filling on the outcome o f endod ontic treatment ofteeth with apical periodontitis. Int Endod J 1997;30:297-306.10. Klevant FJ, Eggink CO. The effect of canal preparation on periapical

disease. Int Endo d J 1983;16:68-75.11. Vertucci FJ. Root canal anatomy of the human permanen t teeth. Oral

Surg Oral Med O ral Pathol 1984;58:589-99.12. Alavi AM, Op asan on A, Ng YL, Gulabivala K. Roo t and ca nal

morphology of Thai maxillary molars. Int Endod J 2002;35:478-85.13. Shovelton DS. The presence an d distribution of microorganisms

within n on-vital teeth . Br Dent J 1964;117:101-7.14. Nair PN. Light and electron m icroscopic studies of root canal flora

and periapical lesions. J Endod 1987;13:29-39.15. Costerton JW, Geesey GG, Cheng KJ. How b acteria stick. Sci Am

1978;238:86-95.16. Jenkinson HF, Lapp in-Scott HM. Biofilms adh ere to stay. Trend s

Microbiol 2001;9:9-10.17. Haapasalo HK, Sirn EK, Waltimo TM, rstavik D, Ha apasalo MP.Inactivation of local root canal me dicaments by d entine: an in vitrostudy. In t Endod J 2000;33:126-31.

18. Porten ier I, Haapasa lo H, Rye A, Waltimo T, rstavik D,Haapasalo M. Inactivation of root canal medicaments by dentine,hydroxylapatite and bovine serum albumin. Int Endod J 2001;34:184-8.

19. Jun g IY, Cho i B, Kum KY, et al. Identification of oral spiroch etes atthe species level and their association with other bacteria inend odo ntic infections. Oral Surg Oral Med O ral Pathol Oral RadiolEndod 2001;92:329-34.

20. Rolph HJ, Lenn on A, Riggio MP, et al. Molecu lar identification ofmicroorganisms from endodontic infections. J Clin Microbiol 2001;39:3282-9.

21. Mun son MA, Pitt-Ford TR, Chong B, Weightman A, Wade WG.Molecular and cultural analysis of the microflora associated withend odontic infections. J Dent Res 2002;81:761-6.

22. Dahln G, Samuelsson W, Moland er A, Reit C. Identification an dantimicrobial susceptibility of en terococci isolated from the root canal.Oral Microbiol Immu nol 2000;15:309-12.

23. rstavik D, Haapasalo M. Disinfection by en dod ontic irrigants anddressings of experimentally infected dentinal tubules. Endod DentTraumatol 1990;6:142-9.

24. Waltimo TM, Sirn EK, rstavik D, Haapasa lo MP. Suscep tibility oforal Candida species to calcium h ydroxide in vitro. Int Endod J 1999;32:94-8.

25. Waltimo TM, rstavik D, Sirn EK, Haap asalo MP. In vitro

susceptibility ofCan dida albican s to four disinfectants and theircombinations. Int Endod J 1999;32:421-9.

26. Molan der A, Reit C, Dahln G, Kvist T. Microbio logical status ofroot-filled teeth with apical periodontitis. Int Endod J 1998;31:1-7.

27. Sundqvist G, Figdor D, Persson S, Sjgren U. Microbiologic ana lysisof teeth with failed endodontic treatment and the outcome ofconservative re-treatment. Oral Surg Oral Med Oral Pathol Oral Radiol

Endod 1998;85:86-93.28. Waltimo TM, Sirn EK, Torkko HL, Olsen I, Haapasalo MP. Fungi intherapy-resistant apical periodontitis. Int Endod J 1997;30:96-101.

29. Sundq vist G, Figdor D. Endod ontic treatment o f apical periodontitis.In: rstavik D, Pitt Ford TR, editors. Essential endodontology. Oxford:Blackwell Science Ltd; 1998:242-77.

30. Clarkson RM, Moule AJ. Sodium hypo chlorite and its use as anend odontic irrigant. Aust Den t J 1998;43:250-6.

31. Pashley EL, Birdson g NL, Bowman K, Pashley DH. Cytotoxic effectsof NaOCl on vital tissue. J Endod 1985;11:525-8.

32. Marais JT. Cleaning e fficacy of a new root canal irrigation so lution: apreliminary evaluation. Int Endod J 2000;33:320-5.

33. Marais JT, Brzel VS. Electro-chem ically activated wate r in d entalunit water lines. Br Den t J 1999;187:154-8.

34. Marais JT, Williams WP. Antimicrobial effectiveness o f electro-

chemically activated water as an end odo ntic irrigation solution.Int Endod J 2001;34:237-43.35. Horiba N, Hiratsuka K, Onoe T, et al. Bactericidal effect of electrolyzed

neutral water on bacteria isolated from infected root canals. OralSurg O ral Med Oral Patho l Oral Radiol Endod 1999;87:83-7.

36. Hata G, Uemura M, Weine FS, Toda T. Removal of smear layer in theroot canal using oxidative potential water. J Endod 1996;22:643-5.

37. Hata G, Hayami S, Weine FS, Tod a T. Effectivene ss of oxidativepotential water as a root canal irrigant. Int Endod J 2001;34:308-17.

38. Solovyeva AM, Dumme r PM. Cleaning effectiveness of root canalirrigation with electrochemically activated anolyte and catholytesolutions: a pilot study. Int Endod J 2000;33:494-504.

39. Torabinejad M, Khademi AA, Babagoli J, et al. A new solution for theremoval of the smear layer. J Endod 2003;29:170-5.

40. Torabinejad M, Cho Y, Khadem i AA, Bakland LK, Shabah ang S.

The effect of various con centrations o f sodium hypoch lorite on theability of MTAD to re move the smear layer. J Endod 2003;29:233-9.

41. Beltz RE, Torab inejad M, Poure smail M. Quan titative ana lysis of thesolubilizing action of MTAD, sodium hypochlorite, and EDTA onbovine pulp and dentin. J Endod 2003;29:334-7.

42. Machn ick TK, Torab inejad M, Mun oz CA, Shab aha ng S. Effect ofMTAD on flexural strength and mod ulus of elasticity of den tin. J Endod2003;29:747-50.

43. Shab ahan g S, Pouresmail M, Torabine jad M. In vitro antimicrobialefficacy of MTAD and sodium hypo chlorite. J Endod 2003;29:450-2.

44. Shab ahan g S, Torab inejad M. Effect of MTAD on Enterococcusfaecalis-contaminated root canals of extracted human teeth. J Endod2003;29:576-9.

45. Torabinejad M, Shab ahan g S, Aprecio RM, Kettering JD. Theantimicrobial effect of MTAD: an in vitro investigation. J Endod 2003;

29:400-3.46. Zhan g W, Torab inejad M, Li Y. Evaluation o f cytotoxicity of MTAD

using the MTT-tetrazolium meth od. J Endod 2003;29:654-7.47. Grigoratos D, Knowles J, Ng YL, Gulabivala K. Effect of exp osing

dentine to sodium hypochlorite and calcium hydroxide on itsflexural strength and elastic modulus. Int Endod J 2001;34:113-9.

48. Sim TP, Know les JC, Ng YL, Shelton J, Gu labivala K. Effect ofsodium hypo chlorite on me chanical prop erties of dentine and too thsurface strain. Int Endo d J 2001;34:120-32.

49. Rajasingh am R, Know les JC, Ng YL, Sobhan i O, Rahbaran S,Gulabivala K. The effect of root canal irrigation with sodiumhypochlorite and EDTA on tooth surface strain. Int Endod J 2004;36:932 [Abstract].

8/3/2019 v1N2_P52_FA1

6/6



50. Dalton BC, rstavik D, Phillips C, Pettiette M, Trop e M. Bacterialreduction with nickel-titanium rotary instrumentation. J Endod 1998;24:763-7.

51. Sique ira Junior JF, Lima KC, Magalhaes FA, Lop es HP, de Uzeda M.Mechanical reduction of bacterial population in the root canal bythree instrumentation techniques. J Endod 1999;25:332-5.

52. Evans GE, Speight PM, Gulabivala K. The influen ce of prep aration

technique and sodium hypochlorite on removal of pulp andpred entine from roo t canals of po sterior teeth. Int Endod J 2001;34:322-30.

53. Lussi A, Nussbcher U, Grosrey J. A novel noninstrumented techniquefor cleansing the root canal system. J Endod 1993;19:549-53.

54. Lussi A, Messerli L, Hotz P, Grosrey J. A new non -instrumentaltechnique for cleaning and filling root can als. Int Endo d J 1995;28:1-6.

55. Portmann P, Lussi A. A comparison betwee n a n ew vacuumobturation technique and lateral condensation: an in vitro study. JEndod 1994;20:292-5.

56. Lussi A, Portmann P, Nussbche r U, Imwinkelried S, Grosrey J.Comparison of two devices for root canal cleansing by thenoninstrumentation technology. J Endod 1999;25:9-13.

57. Lussi A, Imwinkelried S, Stich H. O bturation o f root canals with

different sealers using non -instrumentation technology. Int Endod J1999;32:17-23.58. Lussi A, Suter B, Fritzsche A, Gygax M, Portmann P. In vivo

performance of the new non-instrumentation technology (NIT) forroot canal obturation. Int Endod J 2002;35:352-8.

59. Ardila CN, Wu MK, Wesselink PR. Percentage of filled can al area inmandibular molars after conventional roo t-canal instrumentationand after a non-instrumentation techn ique (NIT). Int Endod J 2003;36:591-8.

60. Attin T, Buchalla W, Zirkel C, Lussi A. Clinical evaluation of thecleansing prope rties of the non instrumen tal techniqu e for cleaningroot canals. Int Endod J 2002;35:929-33.

61. Kimura Y, Wilder-Smith P, Matsumoto K. Lasers in e ndo don tics: areview. Int Endo d J 2000;33:173-85.

62. Khabb az MG, Makropo ulou MI, Serafetinides AA, Papado pou los D,

Papagiakoumou E. Q-switched versus free-running Er:YAG laserefficacy on the roo t canal walls of human tee th: a SEM study. J Endo d2004;30:585-8.

63. Position statement: use of lasers in d entistry. Chicago: AmericanAssociation of Endodontists; 2000.

64. Pini R, Salimbe ni R, Vannini M, Barone R, Clauser C. Laser d entistry:a ne w ap plication of excimer laser in root canal therap y. LasersSurg Med 1989;9:352-7.

65. Mazeki K, Kojy R, Saito K, Fun ato A, Matsumo to K. Morp ho logicalstudy on preparation of root canal orifices by Er:YAG laser. Journalof Japan Endod ontic Association 1998;17:185-9.

66. Levy G. Cleaning an d shap ing the roo t canal with a Nd:YAG laserbeam: a comparative study. J Endod 1992;18:123-7.

67. Sho ji S, Hariu H, Horiuch i H. Canal en largemen t by Er:YAG laserusing a cone-shaped irradiation tip. J Endod 2000;26:454-8.

68. Deutsch AS, Cohe n BI, Musikant BL. Temp erature chan ge at the rootsurface when enlarging a root canal with a holmium:YAG (Ho:YAG)laser, using six different fiber-op tic sizes. Gen Den t 2004;52:222-7.

69. Rizoiu I, Kohangh ado sh F, Kimmel AI, Eversole LR. Pulpal therm alrespon ses to an erbium,chromium:YSGG pulsed laser hydrokineticsystem. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;86:220-3.

70. Chen WH. YSGG laser root canal therapy. Dent Today 2002;21:74-7.71. Altamura C, Majori M, Bedin i R, Filipp ini P. Evaluation of Nd:YAG

laser effects on root canal walls. J Oral Laser Applications 2003;

3:67-72.72. Crespi R, Land o G, Covani U. Cleaning ro ot can als with Nd:YAGlaser: an in vivo study. J Oral Laser App lications 2003;3:27-31.

73. Stevan ovic M, Petrovska M, Stevan ovic M, Mirceva M. Bactericidaleffects of Er:YAG laser irradiation in root canals. J Oral LaserApp lications 2004;4:43-6.

74. Holmes J. Clinical reversal of root caries using ozone, d ouble-blind,randomised, controlled 18-month trial. Gerodontology 2003;20:106-14.

75. Baysan A, Lynch E. Effect of ozon e on the oral microbiota an dclinical severity of p rimary roo t caries. Am J Dent 2004;17:56-60.

76. Baysan A, Whiley RA, Lynch E. Antimicrobial effect of a n ovelozone-genera t ing d evice on micro-organi sms as soc ia tedwith primary root carious lesions in vitro. Caries Res 2000;34:498-501.

77. Hems RS, Spratt DA, Ng YL, Gulabivala K. An in vitro evaluation ofthe ab ility of ozone to killEnterococcus faecalis [Abstract]. Int EndodJ 2002;35:86.

78. Ozonated oils from Pearlywhites Ltd. HealOzone web site: http://www.the-o-zone.cc/oils01.htm.

79. Shipp er G, rstavik D, Teixeira FB, Trop e M. An evalua tion ofmicrobial leakage in roots filled with a thermoplastic syntheticpo lymer-based ro ot can al filling m aterial (Resilon). J Endo d 2004;30:342-7.

80. Burns T, Wilson M, Pearson GJ. Sensitisation of cariogen ic bacteriato killing by light from a helium-neon laser. J Med Microbiol 1993;38:401-5.

81. Sarkar S, Wilson M. Lethal ph otosensitization of bacteria in subgingivalplaque from patients with chronic periodontitis. J Periodontal Res1993;28:204-10.

82. Poh YJ, Ng YL, Spratt D, Gulabivala K, Bhatti M. Lethal p hoto -sensitisation of root canal Fusobacterium nu cleatum isolates[Abstract]. Int Endod J 2000;33:74.

83. Williams JA, Pearso n GJ, Colles MJ, Wilson M. The e ffect ofvariable energy input from a novel light source on the photo-activated bactericidal action of toluidine blue O on Streptococcusmutans. Caries Res 2003;37:190-3.

84. Seal GJ, Ng YL, Spratt D, Bhatti M, Gulabivala K. An in vitrocomp arison of the bactericidal efficacy of lethal ph otosensitiza-tion or sodium hypochlorite irrigation o n Streptococcus intermediusbiofilms in roo t cana ls. Int Endod J 2002;35:268-74.

85. Endox Endod ontic System website: http:// www.end ox.com/indexeng.htm.

86. Haffner C, Benz C, Mehl A, Folwaczny M, Hickel R. High-frequen cycurrent in endodontic therapy: an in-vitro study [Abstract]. J Dent

Res 1999;78(Special Issue):117.87. Position statement: new technologies/materials. Chicago: American

Association o f Endodontists; 2004.

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