|Year : 2015 | Volume
| Issue : 1 | Page : 25-30
Bandu Napte, Surya Raghavendra Srinidhi
Department of Conservative Dentistry and Endodontics, Sinhgad Dental College, Pune, Maharashtra, India
|Date of Web Publication||19-Oct-2015|
Department of Conservative Dentistry and Endodontics, Sinhgad Dental College, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
Endodontic success depends on the triad of biomechanical preparation, pulp space sterilization, and three-dimensional obturation. Complete disinfection of the pulp space cannot be achieved with instrumentation techniques alone. The use of adjunctive aids like endodontic irrigants in achieving this goal is essential. The purpose of this review article is to provide an overview of the different root canal irrigants and their clinical application. A search for English-language papers published in national and international journals using Medline and PubMed indexing was done until April 2014 for sourcing this article.
Keywords: Chlorhexidine, endodontic irrigants, root canal disinfectant, sodium hypochlorite
|How to cite this article:|
Napte B, Srinidhi SR. Endodontic Irrigants. J Dent Allied Sci 2015;4:25-30
| Introduction|| |
Mechanical debridement of the root canal system is done with the use of either hand instruments or rotary nickel-titanium instruments which helps in removal of vital and necrotic remnants of pulp tissue, microorganisms, and microbial toxins. The root canal system has been found to be very complex with anastomoses, cul-de-sacs, and deltas which are difficult if not impossible to clean completely.  This region may accumulate necrotic tissues, microorganisms, and their byproducts resulting in persistent periradicular inflammation. Therefore, root canal irrigation by using various chemical agents is an essential part of debridement as it allows for cleaning more than what might be achieved by root canal instrumentation alone.
| Endodontic Microbiology|| |
The importance of the oral microorganisms causing infection of pulp and periapical lesion formation was shown by Kakehashi et al.  The micro flora of untreated teeth with necrotic pulps is found to be mixed, comprising of Gram-positive and Gram-negative organisms, with a predominance of anaerobic bacteria.  The microorganisms which are found in endodontic treatment failure primarily comprises of one or two species, mostly Gram-positive bacteria with Enterococcus faecalis as the most prevalent organism.  Fungi, Candida albicans can also be found at a significantly higher rate than what is seen in primary infection. 
| Ideal Requirements of an Irrigant|| |
- Should have potent antimicrobial activity
- Should mechanically flush out the debris from the canal
- Should be nontoxic and biocompatible
- Should dissolve necrotic and vital pulp tissues
- Should serve as a lubricant
- Should remove the smear layer
- Should have low surface tension to enable better penetration into dentin tubules.
Classification of root canal irrigants
Based on their mechanism of action, they are classified into nonbactericidal and bactericidal irrigants.
Saline, local anesthetics and distilled water. 
- Sodium hypochlorite (0.5%, 1%, 1.5%, 2.5%, 5.25%, and 6% concentrations)
- Chlorhexidine (CHX) (2%)
- Hydrogen peroxide (H 2 O 2 ) (3%).
- diamine tetra acetic acid (EDTA, 17%)
- Citric acid (10-50%)
- Mixture of tetracycline, acid and detergent (MTAD, Tween 80)
- Maleic acid.
- activated water (EAW)
- Bis-dequalinium acetate (BDA)
- Photo-activated disinfection (PAD)
| Sodium Hypochlorite|| |
Chlorine molecules are the most commonly distributed elements on earth. It is seen in combination with sodium, potassium, calcium, and magnesium.  In the body, it is formed in neutrophils through the myeloperoxidase-mediated chlorination of a nitrogenous compound. 
Buffered 0.5% sodium hypochlorite was initially used for the irrigation of the infected wounds.  Sodium hypochlorite is sporicidal, virucidal and shows tissue dissolving effect on tissues. These characteristics popularized the use of aqueous sodium hypochlorite in endodontics as early as 1920. Furthermore, sodium hypochlorite solutions have minimum cost and easily available and demonstrated good shelf life. There are other derivatives of chlorine like chloramine-T and sodium dichloroisocyanurate. , These, however, are less effective than sodium hypochlorite at similar concentrations. ,
Mechanism of action
NaOCl has two important properties, namely, antimicrobial activity, and organic tissue dissolution. This can be shown by reactions that take place when NaOCl comes in contact with the organic tissues or microorganisms. 
NaOCl has organic tissue dissolving properties which will help in degrading fatty acids and transforming them into fatty acid salts (soap) and glycerol (alcohol) which will help to reduce the surface tension of the remaining solution. 
NaOCl buffers the amino acids forming water and salt. Formation of hydroxyl ions takes place which leads to the reduction of pH.
In the next step, hypochlorous acid combines with protein amino groups to form chloramines. This reaction between chlorine and the amino group (NH) leads to the formation of chloramines that interfere with the cell metabolism. Antimicrobial action of chlorine occurs by inhibiting bacterial enzymes and leading to an oxidation of SH groups (sulphydryl groups) of bacterial enzymes. 
Methods to increase the efficacy of NaOCl
Warming of low concentration NaOCl solution increases the efficacy of tissue dissolution and its antibacterial properties. Recent studies showed that a temperature rise of 25°C increased NaOCl efficacy by 100 times.  The temperature and concentration effect suggest that the capacity of 1% of NaOCl at 45°C to dissolve pulp tissue is found to be equal to that of a 5.25% of the solution at 20°C. 
2. Ultrasonic agitation
The ultrasonic agitation with a small file (mostly ISO no. 15) in canals filled with NaOCl lead to the development of ultrasonic energy which warms the solution in the canal. The vibrations cause movement of aqueous NaOCl into the ramifications in the canal, this effect being called as "acoustic streaming." 
3. Use of fresh solution
Freshly prepared NaOCl solutions have better antimicrobial and tissue dissolving effects. Since NaOCl decomposes quickly, it is stored in opaque containers.
4. Increasing the volume and the duration of the irrigation.
| Chlorhexidine Digluconate|| |
It belongs to the poly biguanide family, substances which have a positive charge.  The antibacterial effect of CHX is due to its positive charge, which is attracted to the negatively charged bacterial cell wall and increases the permeability of bacterial contents.  Bacteriostatic property of CHX will occur at low concentrations. At higher concentrations, it shows the bactericidal effect which leads to the coagulation and precipitation of the cytoplasmic membrane.  CHX is effective against Gram-positive microbes and thus can be used in retreatment cases. Studies have shown that it can be used against C. albicans and E. faecalis. 
Mechanism of action
CHX reacts with negatively charged components of the bacterial cell surface, causing a loss of cytoplasmic constituents, membrane damage, and enzyme inhibition. At higher concentrations, CHX causes extensive bacterial cell damage, coagulation of cytoplasm, and precipitation of proteins and nucleic acids. 
CHX has a broad spectrum of action on microorganisms such as Gram-positive and Gram-negative bacteria, spores, virus, yeast, and dermatophytes.  It shows increased antimicrobial activity against endodontic pathogens like Staphylococcus aureus, Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, E. faecalis, C. albicans, and Streptococcus mutants. , It can be used in liquid or gel formulations. The CHX gel makes the instrumentation easier and also reduces the smear layer formation better than the liquid formulation. 
Due to the cationic nature of the CHX molecule, it can be adsorbed by the hydroxyapatite and the teeth. At concentrations >0.02%, a layer of CHX is formed on the tooth surface which may reduce or prevent bacterial colonization. Rossi-Fedele et al. in their study quoted Rosenthal et al. saying substantivity of 2% CHX solution within the root canal is present after 10 min of application. CHX was antimicrobial effective in the root canal dentine for a period of up to 12 weeks. 
Iodine, used in endodontics in 1979, was found to be an antiseptic against a large number of microbes.  Iodine is bactericidal, fungicidal, virucidal, sporicidal, degrades proteins, nucleotides, and fatty acids, leading to bacterial cell death.  The advantages of iodine over the other irrigants is that 2% of preparations are shown to be less irritating, poisonous, and rapidly reduces the bacterial load.  Two percent IKI needs 1-2 h to inhibit the development of E. faecalis and C. albicans.  Iodine has the capability to penetrate all the way through dentinal tubules and destroy bacteria, though the period of its antimicrobial action is less.  It has the disadvantage of staining dentin tissue. 
H 2 O 2 is available in 3% to 5% of concentrations.  It is effective against bacteria, spores, viruses, and yeasts by the formation of free radicals which causes degradation of cell components such as proteins and DNA.  The antibacterial action and tissue dissolving capability of H 2 O 2 are less than that of NaOCl. Combined action of H 2 O 2 and CHX has better antibacterial action.
| Chelating Agents|| |
Chelating agents were introduced for the first time by Nygaard Ostby in 1957.  Hypochlorite solutions were unable to remove the smear layer and demineralizing agents such as EDTA, and citric acid have been suggested for the removal of smear layer during root canal treatment. 
Ethylene diamine tetra acetic acid
It is available in concentrations of 17% as a root canal irrigant with a pH of 7.  It kills microbes by chelating with metallic ions needed for growth of bacteria.  The concentrations of 15-17% eliminates calcium from dentine leaving an organic matrix and removes the smear layer. Application of EDTA in the root canal system is done for 1-5 min to get the optimum effect. The use of EDTA at a concentration of 17% for ≥10 min has been lead to cause erosion of peritubular and intertubular dentine.  With the combination of EDTA and NaOCl, both the inorganic and the organic components are removed, and clean dentinal tubules are obtained. EDTA interacts with NaOCl and can decrease the free chlorine, thereby affecting the outcome of NaOCl. 
The addition of a quaternary ammonium bromide (Cetavlon) increases the action of EDTA by decreasing its surface tension. This combination is called as EDTAC, and it is effective in smear layer removal and increasing the diameter of opened dentin tubules. 
It is available in 10-50% concentration which is a demineralizing solution that is used during the endodontic therapy to remove the smear layer from the prepared root canal.  Citric acid interferes with the mechanism of action of NaOCl. Citric acid 10% is more biocompatible and effective in removing smear layer than 17% of EDTA. 
Mixture of tetracycline, acid, and detergent
It is a mixture of an antibiotic (3% doxycycline), a chelating agent (citric acid), and a detergent (Tween 80). Citric acid eliminates the smear layer, allowing the doxycycline to pass into the dentinal tubules and cause an antibacterial effect. The protocol for clinical use of MTAD is 1.3% NaOCl for 20 min followed by 5 min application of MTAD.  There may be a risk of development of bacterial resistance, intrinsic staining of dentine, and sensitivity of tooth.
Tetraclean is similar to MTAD, the only difference being the addition of doxycycline-50 mg/ml and a detergent (polypropylene glycol). It is effective against both anaerobic and facultative bacteria. It removes the smear layer and opens up the dentinal tubule orifices. It has shown low surface tension which allows better penetration of the solution into the dentinal tubule.  In vitro studies have proved that Tetraclean is more efficient than MTAD against E. faecalis. 
Maleic acid is a mild organic acid used as an acid conditioner in adhesive dentistry at 5-7% concentration. Final irrigation with 7% of maleic acid is more efficient than 17% of EDTA in the removal of smear layer from the apical third of the root canal system, which is a crucial area for disinfection. , 7% of maleic acid produces maximum surface roughness on root canal walls as compared to 17% of EDTA. This surface roughness provides an important role in micromechanical bonding of resin sealers. 
| Bis-dequalinium Acetate|| |
BDA, a dequalinium compound and an oxine derivative with the trade name Salvizol has been shown to remove the smear layer throughout the canal, even in the apical third. , BDA is well-tolerated by periodontal tissues and has a low surface tension allowing good penetration. It is considered less toxic than NaOCl and can be used as a root canal dressing. Kaufman (1983)  reported that Salvizol had better cleaning properties than EDTAC. A commercial form of BDA called Solvidont (De Trey, A.G., Zurich, Switzerland) was available initially and its use as an alternative to NaOCl was supported by many studies. ,, Salvizol (Ravens Gmbh, Konstanz, Germany) is a commercial brand of 0.5% BDA and possesses the combined actions of chelation and organic debridement. ,
| Photo-activated Disinfection|| |
Oscar Raab introduced the photo-activated therapy for the inactivation of microorganisms in the endodontic management.  PAD is the placement of a dye (toluidine blue or methylene blue) into the root canals which is then activated by the laser radiation emitted from a low power (100 mW) laser device, causing interference with the microbial cell walls and bacterial death. , After normal irrigation, the canals are washed with sterile water, and they are dried by sterilized paper points before the application of the PAD solution into the canals. The photosensitizer molecules will attach to the membrane of the microorganisms and the irradiation with a precise wavelength coordinated to the absorption of the photosensitizer will form singlet oxygen which causes cell wall rupture and death of the microbes.
The benefit of PAD is that the dye is only poisonous to bacteria, and there are no side effects to adjacent tissues.
| Ozone|| |
It occurs in the environment either in gaseous form or as ozonated water.  It is an antiseptic, powerful oxidant, and antibacterial agent. It is a strong oxidizer of cell walls and the cytoplasmic membranes of microorganisms, making it a bactericidal, antiviral, and antifungal agent. 
| Electronically Activated Water|| |
The ECW technology is a symbol of an innovative scientific paradigm introduced by Russian scientists.  EAW is also recognized as oxidative potential water. It is an electrolyzed saline solution and usually utilized to remove the microbial contamination and biofilm from the dental unit piping and tubing. It is able to disturb biofilms by reducing the adhering capability of bacteria to the canal walls by generating a negative isotonic pressure. 
Neodymium: Yttrium aluminum garnet lasers have been recently introduced for the disinfection in endodontic therapy. However, it was established that when there was direct contact to the laser, all root canal systems were not entirely eliminated of bacteria and lasers were not superior to irrigation with NaOCl. 
Azadirachta indica , commonly known as Neem, is an evergreen tree, cultivated in several parts of the Indian subcontinent. Every part of the tree is used as traditional medicine for the household remedy against various human ailments, from the ancient period. , Neem has been proved to be effective against E. faecalis and C. albicans. Its antioxidant and antimicrobial properties makes it a potential agent for root canal irrigation as an alternative to sodium hypochlorite. 
Chlorine dioxide (ClO 2 ) is chemically similar to chlorine or hypochlorite, the familiar household bleach. An in vitro study compared organic tissue dissolution capacity of NaOCl and ClO 2 . It was concluded that ClO 2 and NaOCl are equally efficient for dissolving organic tissue.  ClO 2 produces little or no trihalomethanes. A study showed that trihalomethane is an animal carcinogen and a suspected human carcinogen. ClO 2 might, therefore, be a better dental irrigant than NaOCl. 
Silver diamine fluoride
A 3.8% of w/v silver diamine fluoride (Ag(NH 3 )2F) solution has been developed for intracanal irrigation. This represents a 1:10 dilution of the original 38% of Ag(NH 3 )2F solution used for root canal infection.  The study on the antibacterial effect of 3.8% of Ag(NH 3 )2F against a E. faecalis biofilm model concluded that Ag(NH 3 )2F has potential for use as an antimicrobial root canal irrigant or interappointment medicament to reduce bacterial loads. 
Triclosan and gantrez
The addition of Gantrez® (Poly Methyl Vinyl Ether-co-maleic anhydride, PVM/MA) enhanced the bactericidal activity of Triclosan. Both Triclosan and Triclosan with Gantrez® demonstrated bactericidal activity against the five specific endodontic pathogens (P. intermedia, Fusobacterium nucleatum, Actinomyces naeslundii, P. gingivalis, and E. faecalis). 
| Herbal Irrigants|| |
Triphala consists of dried and powdered fruits of three medicinal plants Terminalia bellerica, Terminalia chebula, and Emblica officinalis. Triphala achieved 100% killing of E. faecalis at 6 min. Triphala contains fruits that are rich in citric acid, which may aid in removal of the smear layer. 
Green tea polyphenols showed a statistically significant antibacterial activity against E. faecalis biofilm formed on tooth substrate. It takes 6 min to achieve 100% killing of E. faecalis. 
Morinda citrifolia juice
Morinda citrifolia juice (MCJ) has a broad range of therapeutic effects, including antibacterial, antiviral, antifungal, antitumor, antihelmintic, analgesic, hypotensive, anti-inflammatory, and immune-enhancing effects. MCJ is a biocompatible antioxidant and not likely to cause severe injuries to patients as might occur through NaOCl accidents. 
| Conclusion|| |
Selection and use of the correct irrigant for the different clinical situations will help to achieve predictable endodontic success.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Peters OA, Schönenberger K, Laib A. Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography. Int Endod J 2001;34:221-30.
Kakehashi S, Stanley HR, Fitzgerald RJ. The effects of surgical exposures of dental pulps in germ-free and conventional laboratory rats. J Oral Surg 1965;20:340-9.
Siqueira JF Jr, Rôças IN. Exploiting molecular methods to explore endodontic infections: Part 2-Redefining the endodontic microbiota. J Endod 2005;31:488-98.
Pinheiro ET, Gomes BP, Ferraz CC, Sousa EL, Teixeira FB, Souza-Filho FJ. Microorganisms from canals of root-filled teeth with periapical lesions. Int Endod J 2003;36:1-11.
Peciuliene V, Reynaud AH, Balciuniene I, Haapasalo M. Isolation of yeasts and enteric bacteria in root-filled teeth with chronic apical periodontitis. Int Endod J 2001;34:429-34.
Good M, El KI, Hussey DL. Endodontic ′solutions′ part 1: A literature review on the use of endodontic lubricants, irrigants and medicaments. Dent Update 2012;39:239-40, 242-4, 246.
Dychdala GR. Chlorine and chlorine compounds. In: Block SS, editor. Disinfection, Sterilization and Preservation. Philadelphia: Lea & Febiger; 1991. p. 131-51.
Mistry KS, Shah S. Review on common root canal irrigants. J Dent Sci 2011;2:27-31.
Ng YL, Mann V, Gulabivala K. A prospective study of the factors affecting outcomes of nonsurgical root canal treatment: part 1: Periapical health. Int Endod J 2011;44:583-609.
Rossi-Fedele G, Guastalli AR, Dogramaci EJ, Steier L, De Figueiredo JA. Influence of pH changes on chlorine-containing endodontic irrigating solutions. Int Endod J 2011;44:792-9.
Denton GW. Chlorhexidine. In: Block SS, editor. Disinfection, Sterilization and Preservation. 4 th
ed. Philadelphia: Lea &Febiger; 1991. p. 274-89.
Rosetti Lessa FC, Nogueira I, Silveira F. Direct and transdentinal antibacterial activity of chlorhexidine. Am J Dent 2010;25:255-9.
Sauerbrei A, Wutzler P. Virucidal efficacy of povidone-iodine-containing disinfectants. Lett Appl Microbiol 2010;51:158-63.
Mohammadi Z, Abbott PV. Antimicrobial substantivity of root canal irrigants and medicaments: A review. Aust Endod J 2009;35:131-9.
Gu LS, Kim JR, Ling J, Choi KK, Pashley DH, Tay FR. Review of contemporary irrigant agitation techniques and devices. J Endod 2009;35:791-804.
Steinberg D, Heling I, Daniel I, Ginsburg I. Antibacterial synergistic effect of chlorhexidine and hydrogen peroxide against Streptococcus sobrinus
, Streptococcus faecalis
, Staphylococcus aureus
. J Oral Rehabil 1999;26:151-6.
Asghar S, Ali A, Somoro S, Rashid S. Antimicrobial solutions used for root canal disinfection. Pak Oral Dent J 2013;33:165-71.
Sayin TC, Serper A, Cehreli ZC, Otlu HG. The effect of EDTA, EGTA, EDTAC, and tetracycline-HCl with and without subsequent NaOCl treatment on the microhardness of root canal dentin. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:418-24.
Valera MC, Chung A, Menezes MM, Fernandes CE, Carvalho CA, Camargo SE, et al.
Scanning electron microscope evaluation of chlorhexidine gel and liquid associated with sodium hypochlorite cleaning on the root canal walls. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:e82-7.
Prabhu SG, Rahim N, Bhat KS, Mathew J. Comparison of removal of endodontic smear layer using NaOCl, EDTA, and different concentrations of Maleic acid - A SEM study. Endodontology 2003;15:20-5.
Ballal NV, Kandian S, Mala K, Bhat KS, Acharya S. Comparison of the efficacy of maleic acid and ethylenediaminetetraacetic acid in smear layer removal from instrumented human root canal: A scanning electron microscopic study. J Endod 2009;35:1573-6.
Ballal NV, Kandian S, Kundabala M, Bhat KS. Evaluation of the effect of Maleic acid and EDTA on micro hardness and surface roughness of human root canal dentin. J Endod 2010;36:1385-8.
Kaufman AY, Binderman I, Tal M, Gedalia I, Peretz G. New chemotherapeutic agent for root canal treatment. A preliminary electron microscopic study on an in vivo
and in vitro
endodontically treated tooth. Oral Surg Oral Med Oral Pathol 1978;46:283-95.
Kaufman AY. The use of dequalinium acetate as a disinfectant and chemotherapeutic agent in endodontics. Oral Surg Oral Med Oral Pathol 1981;51:434-41.
Kaufman AY. Solvidont - A new chemotherapeutic and bactericidal agent for endodontic use (I). Quintessence Int 1983;14:71-9.
Kaufman AY. Solvidont - A new chemotherapeutic and bacteriocidal agent for endodontic use (II). Quintessence Int 1983;14:235-44.
Chandler NP, Lilley JD. Clinical trial of a bis-dequalinium-acetate solution as an endodontic irrigant. J Dent Res 1987;66:842.
Lilley JD, Russell C, Chandler NP. Comparison of bisdequalinium-acetate and sodium hypochlorite solutions as endodontic irrigants. J Dent Res 1988;67:300.
Mohd Sulong MZ. The incidence of postoperative pain after canal preparation of open teeth using two irrigation regimes. Int Endod J 1989;22:248-51.
Kaufman AY, Greenberg I. Comparative study of the configuration and the cleanliness level of root canals prepared with the aid of sodium hypochlorite and bis-dequalinium-acetate solutions. Oral Surg Oral Med Oral Pathol 1986;62:191-7.
Salvadori MF. Genotoxicity of antimicrobial endodontic compounds by single cell gel assay in Chinese hamster ovary cells. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;99:637-40.
Giardino L, Ambu E, Becce C, Rimondini L, Morra M. Surface tension comparison of four common root canal irrigants and two new irrigants containing antibiotic. J Endod 2006;32:1091-3.
Baumgartner JC, Ibay AC. The chemical reactions of irrigants used for root canal debridement. J Endod 1987;13:47-51.
Pappen FG, Shen Y, Qian W, Leonardo MR, Giardino L, Haapasalo M. In vitro
antibacterial action of Tetraclean, MTAD and five experimental irrigation solutions. Int Endod J 2010;43:528-35.
Giardino L, Ambu E, Savoldi E, Rimondini R, Cassanelli C, Debbia EA. Comparative evaluation of antimicrobial efficacy of sodium hypochlorite, MTAD, and Tetraclean against Enterococcus faecalis
biofilm. J Endod 2007;33:852-5.
Nayar SL, Chopra RN, Chopra IC. Glossary of Indian Medicinal Plants. CSIR, New Delhi; 1956.
Chatterjee A, Pakrashi S (eds). The Treatise on Indian Medicinal Plants. Vol 3, 1994. p. 76. Publications and Information Directorate, CSIR, New Delhi.
Bohora A, Hegde V, Kokate S. Comparison of antibacterial efficacy of neem leaf extract and 2% sodium hypochlorite against E. faecalis
, C. albicans
and mixed culture - An in vitro
study. Endodontology 2010;22:8-12.
Kandaswamy D, Venkateshbabu N. Root canal irrigants. J Conserv Dent 2010;13:256-64.