Background:During the last several years endodontics has progressed so that the treatmentis less traumatic for the patient and less stressful for the dentist. There aremany techniques available to accomplish the root canal preparation. We must askourselves the question, "Why do we irrigate and what irrigation protocolwill provide the cleanest canal?" In this context, let us remember thatthe shaping is the result of endodontic instruments while the cleaning resultsfrom irrigation.

Aims: The purpose of this study was to determine current trends in irrigationselection among dentists.

Methods and Material: Two hundred dentists wererandomly approached. Participantswere asked about their irrigant selection, irrigant concentration, and use ofadjuncts to irrigation.

Statistical analysis used: SPSS 16

Results: Most frequently usedirrigants are combination of sodium hypochlorite, saline and chlorhexidine. Theuse of irrigant varies in different clinical situations.

Conclusions: Sodium hypochlorite is the most commonly used andpreferred solution.

Key-words: chlorhexidine , EDTA, sodiumhypochlorite.




Dr. Herbert Schilder insisted on "cleaning andshaping". It may be more appropriate to say, "shaping for cleaning”.The main goal of the root canal treatment is to completely eliminate thedifferent components of the pulpal tissue, calcification and bacteria. The mostcommonly used irrigating solution is sodium hypochlorite. It performsbactericidal, cytotoxic, dissolution of organic material, and minor lubrication1.Alternatives to sodium hypoclorite irrigation are necessary because of itsirritating properties and potential for severe inflammatory reactions1.Although many different irrigants and treatment protocols have been studied,little research has been done to determine its widespread acceptance. Thepurpose of this study was to ascertain the current trends in irrigation amongdentists in the city of Mumbai.

Subjects and Methods:

Two hundred registered dentistspracticing in Mumbai were approached in a random manner. They were requested toparticipate in a clinical research. Clinical research participants were asked16 questions consisting of multiple choice, multiple selections with optionsfor write-in answers where appropriate. Data were collected and analyzed usingSPSS 16.


1) How many years you have beenpracticing?

   1year.                                        1-5years.

5-10 years.                               More than 10years.

2) Do you do endodontics in yourpractice?

   Yes.                                           No.

3) Which irrigants do you use?

   Sodium hypochlorite.           Saline.

   Chlorhexidine.                       EDTA.

   Sterile water.                          Other ? specify __________________________

4) Which concentration of sodiumhypochlorite do you use?

   Less than 0.5%.                      0.5-1.5%.

   1.6-2.5%.                                2.6-4.0%.

   4.1-5%.                                    More than5%.

5) What temperature of sodiumhypochlorite is used?

   Heated, Temperature ___________              Room temperature .

6) Do you use any other irrigant inconjugation with sodium hypochlorite?

   Yes, specify_____________________________           No.

7) Does your choice of irrigantchange based on pulpal involvement or periapical involvement?

   Yes.                                                                  No.

8) Which irrigant do you use forvital tooth?

   Sodium hypochlorite.        Saline.

   Chlorhexidine.                     EDTA.

   Sterile water.                       Other ? specify_____________________________

9) Which irrigant do you use fornecrotic tooth?

   Sodium hypochlorite.          Saline.

   Chlorhexidine.                      EDTA.

   Sterile water.                         Other ? specify______________________________

10) Which irrigant do you use forimmature tooth?

   Sodium hypochlorite.        Saline.

   Chlorhexidine.                    EDTA.

   Sterile water.                      Other ? specify_____________________________

11) Which irrigant do you use for atooth with radiographic evidence of periapical lesion?

   Sodium hypochlorite.       Saline.

   Chlorhexidine.                    EDTA.

   Sterile water.                      Other ? specify_____________________________

12) Which irrigant do you use forretreatment cases?

   Sodium hypochlorite.       Saline.

   Chlorhexidine.                   EDTA.

   Sterile water.                      Other ? specify_____________________________

13) Do you use any adjuncts toirrigants you use?

   Yes.                                         No. 

14) Which adjuct do you use?

   Ultrasonic activation.                              Sonic activation.

   Subsonic activation (endoactivator).   Negative pressure (endovac).

Other? Specify________________________

15) What is your recall time?

   1 week .                      2weeks.

   6 months.                   Others? Specify___________________

16) Are you satisfied by theresults obtained by the technique you use?

   Yes.                                No.










Mostfrequently used irrigants are combination of sodium hypochlorite, saline andchlorhexidine.(Fig 1). The concentration of sodium hypoclorite most preferredis 2.6-4.0% (Fig 2). Sodium hypochlorite is ordinarily used at room temperature.(Fig 3). Usually sodium hypochlorite was used in combination with otherirrigants(Fig 4). The choice of irrigants depended on pulpal involvement.(Fig 5). The use of irrigant varies in different clinical situations.

  1. Vital tooth – sodium hypochlorite
  2. Necrotic tooth – combination of sodium hypochlorite, saline chlorhexidine and EDTA.
  3. Immature tooth – saline
  4. A tooth with periapical lesion – combination of sodium hypochlorite and saline
  5. Retreatment cases – combination of sodium hypochlorite, saline, EDTA




Sodium hypochlorite is widely used as anirrigant since its introduction in endodontics by Walker in 19362..It was used as wound irrigants up to 19153 and has become the mostpopular irrigation solution in endodontics since Crane described the use ofDakin’s solution (0.5 % Sodium hypoclorite), in 1920.  In addition to bleaching, deodorizing andtissue-dissolving properties , Sodium hypoclorite has been demonstrated to bean effective disinfectant agent. Sodium hypochlorite has been demonstrated tobe an effective agent against a broad spectrum of bacteria and to dissolvevital as well as necrotic tissue4. Different irrigation regimens have been proposed to enhance theeffectiveness of Sodium hypoclorite in disinfecting the root canal system.Grossman (1943) suggested the alternate use of Sodium hypoclorite and hydrogenperoxide (H2O2) for the irrigation of the root canal. This associationcaused   effervescence, which may improvethe debridement and disinfection of the root canal. Martin (1976) has proposedirrigation with Sodium hypoclorite solution during ultrasonic instrumentationof the root canal   system. He claimedthat ultrasonic waves accelerate chemical reactions and potentiate thebactericidal efficiency of Sodium hypoclorite. Studies have demonstrated that ultrasonication of Sodium hypocloritesolution increases its cleaning and antibacterial effects5.  The effective concentration range of Sodiumhypoclorite is from 2.6 to 5.25%. Heating sodium hypochlorite enhances its tissuesolubility and debridement properties6. However in the present studythe most commonly used concentration is in the desired range of 2.6 to 4percent  (fig 2)  but is used most commonly at room temperaturegiving practitioners desired results (fig 3). Optimizing the concentration,temperature, flow, and surface tension can improve the tissue dissolvingeffectiveness of hypochlorite even 50-fold7. Density, pH, viscosity,wetting capacity and conductivity of the solution are directly proportional toconcentration of Sodium hypoclorite.

Objectives And Properties Of Irrigants 8

·        Be highlyefficacious against endodontic flora.

·        Neutralizethe components of endodontic infection.

·        Intenseand direct action against endodontic flora.

·        Facilitatethe action of instrumentation.

·        Alter thepH of enviornment.

·        Removeblood in pulp cavity.

·        Preventsmear layer formation, favor action of intracanal medicaments.

·        Removeorganic and inorganic matter.

·        Have goodtissue tolerance.

·        Penetratethe entire root canal.


Mechanism of action

Pecora et al.reported that sodium hypochlorite exhibits a dynamic balance .



Sodiumhypochlorite acts as an organic and fat solvent degrading fatty acids,transforming them into fatty acid salts (soap) and glycerol (alcohol), thatreduces the surface tension of the remaining solution ( saponificationreaction).


        O                                              O

         êê                                              êê

R-C-O-R   +    NaOH      Û    R-C-O-Na +  R-OH


Fatty acid        sodium              soap             glycerol







    H     O                                                    Cl     O

     ê      êê                                                    ê       êê

R-C-O-C         +      HOCl       Û          R-C-O-C    +   H2O

     ê       ê                                                     ê       ê

   NH2  OH                                                NH2  OH



Amino acid           Hypochlorous           Cholramine     water



With the exit ofhydroxyl ions, there is a reduction of pH. Hypochlorous acid, a substancepresent in sodium hypochlorite solution, when in contact with organic tissueacts as a solvent, releases chlorine that, combined with the protein aminogroup, forms chloramines (chloramination reaction). Hypochlorous acid (HOCl-)and hypochlorite ions (OCl-) lead to amino acid degradation andhydrolysis.

Thechloramination reaction between chlorine and the amino group (NH) formschloramines that interfere in cell metabolism. Chlorine (strong oxidant)presents antimicrobial action inhibiting bacterial enzymes leading to anirreversible oxidation of SH groups (sulphydryl group) of essential bacterial enzymes(cystein).

Sodiumhypochlorite neutralizes amino acids forming water and salt (neutralizationreaction).


   H      O                                       H      O

    ê       êê                                       ê       êê

R-C-O-C     +    NaOH   Û     R-C-O-C    +    H2O

    ê        ê                                        ê      ê

  NH2  OH                                   NH2   Na

Amino acid      sodium                 salt               water



Sodium hypochloriteis a strong base (pH>11). At 1% concentration, sodium hypochlorite presentsa surface tension equal to 75 dynes/cm, stickiness equal to 0.986 cP, 65.5 mSof conductivity, 1.04 g/cm3 of density and moistening capacityequal to 1 h and 27 min. Its antimicrobial mechanism of action can be observedverifying its physico-chemical characteristics and its reaction with organictissue. The antimicrobial effectiveness of sodium hypochlorite, based in itshigh pH (hydroxyl ions action), is similar to the mechanism of action ofcalcium hydroxide. The high pH of sodium hypochlorite interferes in thecytoplasmic membrane integrity with an irreversible enzymatic inhibition,biosynthetic alterations in cellular metabolism and phospholipid degradationobserved in lipidic peroxidation. Grossman and Meiman  observed pulp tissue dissolution capacity, of5% sodium hypochlorite dissolves is 20 min to 2 h9.

      In this study, it was found that theoverwhelming majority used sodium hypochlorite as primary irrigant. The reasonfor same being its antibacterial and tissue dissolving properties. This resultsare in accordance with previous surveys conducted elsewhere. In United Kingdom asurvey conducted reported around 71% of rubberdam users used sodiumhypochlorite.10 Another survey in Australia reported 94% ofendodontists use sodium hypochlorite as primary irrigant.11 in thisstudy it is evident that the choice of irrigant is based on the pulpaldiagnosis where 70%  of clinicalconditions require the use of sodium hypochlorite only or in combination withother irrigants. ( fig 4 and fig 5)


Sodium hypochlorite is themost commonly used and preferred solution. The choice of irrigant also variesaccording to nature of lesion. Sodium hypoclorite is also used in variousconcentration and in conjugation with other irrigants. Sodium hypoclorite hasbeen used with different adjuncts at different temperature in differentclinical situations.