Irrigation Methods In Endodontics

               Irrigation : The Powerful weapon

Dental Post – 1

#Irrigatewisely

The success of endodontic treatment is completely relied on the principle of 3 dimensional cleaning and shaping root canal system by complete eradication of pathogenic microorganisms and necrotic pulp. And IRRIGATION plays central role in endodontic treatment.

How Irrigation works? Why it is important step? Which all solutions and methods are used ? And in what sequence it is used ?

I will try to explain this topic more practical point of view  because more of us  don't  know how to apply our theory knowledge when it is needed while doing cases. Let’s start.

What is irrigation and how it works?

Irrigation means flushing the root canal space with different irrigating solutions to remove all the inflamed pulp tissue and debris  and also to reach all the inaccessible areas where mechanical cleansing doesn't work well.

During the cleaning and shaping phases of an endodontic treatment it is possible to distinguish chemical  and mechanical cleansing. Mechanical cleansing, in addition to the removal of necrotic or vital pulp tissue leads to the formation of a thin layer of debris known as " smear layer". This SMEAR LAYER is made up of potentially infective organic and inorganic substances that must be removed from the canal walls, dentin tubules and root canal branches with the aid of root canal irrigants that is chemical cleansing.

Methods of Irrigation –

There are mainly four types :

1. Apical  Negative  Pressure  System (ANP) - This system is introduced to simultaneously release and remove the irrigant. These systems comprises a macrocanula for the coronal and middle portion and a microcannula for the apical portion, which are connected to a syringe for Irrigation. This system has the purpose to ensure a constant and continuous flow of new irrigant in the apical 3rd with safety and a lower risk of extrusion.
• Examples – Endovac system,  Endoirrigator plus

Cost Effective  Alternatives : You can attach metapex tip to suction tip which will remove the irrigant from the canal and normal needle syringe to release irrigant in the canal

2. Manual  Dynamic  Agitation (MDA) - It is a simple & cost effective technique which involves repeated insertion of a well fitting gutta percha cone in short vertical strokes to hydrodynamically displace & agitate an irrigant. Here the canal is filled with 5.25% sodium hypochlorite (NaOCl) & push pull strokes are performed manually, 1-2 mm short to the working length at an approximate rate of 100 strokes/min for minimum 30 seconds to 1 min.

3. Ultrasonic Irrigation system – Ultrasonic irrigation of the root canal can be performed with or without simultaneous ultrasonic instrumentation. When canal shaping is not undertaken the term PUI can be used that is ‘Passive ultrasonic irrigation'. PUI is the non cutting technique which reduces the potential for creating aberrant shapes in the root canal ( like apical zips, perforations). This method is more effective than  sonic activation and manual Irrigation as  it creates a higher speed and flow volume of the irrigant in the canal during Irrigation thereby eliminating more debris, producing less apical packing, better access of the chemical product to accessory canals and even the flush effect is produced by ultrasonics but not manual irrigation.
• Example – Endoultra

4. Sonic activation system - Most actual systems have smooth plastic tips of different sizes activated at sonic frequency by a handpiece . This effectively clean the main canal, to remove the smear layer  and to promote the filling of a greater number of lateral canal. Recently introduced technique uses a syringe with sonic vibration that allows the delivery & activation of the irrigant in the root canal at the same time.
• Example – PATS system ( air sonic activation), Endoactivator system, MM 1500

5. Needle Irrigation (NI) - In this method, solutions are delivered by a syringe and a 30 guage needle. The tip is placed as deep as possible( but 1-2 mm short to Apex) in the canal without wedging to permit backflow of the irrigant.

• Other cost effective alternative for activation of irrigant:

1) You can use ultrasonic activator tip which can be attached with your ultrasonic scaler.
2) You can attach Endoactivator tip to waterpik flosser.
3) 'U' files – They can be used in conjunction with 120° file holder that is endochuck which can be fitted onto an  ultrasonic scaler handpiece.

                                                                                                                                                     
 “Apical vapour lock effect” :                            

   Apical vapour lock is consistently formed during routine endodontic irrigation which impedes irrigant penetration till the working length thereby leading to insufficient debridement. This problem can be minimised by negative pressure irrigation OR techniques such as sonics/ultrasonics, Laser induced activation.

            
                                                                         

• Solutions used for Irrigation –

Mainly 4 solutions are used and these are,

1) Sodium Hypochlorite (NaOCl) : 

• Most potent irrigant and used at 3–5.25% concentration.
• Use NaOCl continuously throughout instrumentation, atleast for 30 min.
• Replenish NaOCl after every minute as chlorine ion  which is responsible for tissue dissolving and antibacterial capacity is unstable and consumed rapidly during 1st phase of tissue dissolution and it looses it’s efficiency after 0.8 to 1.2 minute.
• The hand that holds the irigating syringe is always kept in motion when dispensing irrigant to prevent needle from inadvertently wedging in canal leading to hypo- accident.
• But it is unable to remove smear layer.
• Some authors say that warm NaOCl (50°-60°)  is more efficient and gives good results.

2) Ethylene Diamine Tetraacetic Acid (EDTA) :

• Most common solution used to eliminate the inorganic residues, but not removed by NaOCl is a pH 7 solution of EDTA.
• EDTA has no antibacterial properties but can remove the smear layer deposited by the mechanical action of instruments, making the canal walls accessible again to disinfectants.
• It is used at 17 % concentration.

3) Chlorhexidine (CHX) :
• It has a efficient antibacterial activity in an endodontic environment, if used at a concentration of 2%.
• CHX cannot remove necrotic residues and can not also be used as a substitute of NaOCl.
• Never mix  NaOCl  and CHX in root canal as the mixture of these two solutions forms brown precipitation of para chloroaniline (PCA). And these precipitations are difficult to remove from root canal and may cause discoloration of tooth.
• CHX must be used as a final irrigant in secondary infections. Because  it is effective against E. Faecalis which are mainly responsible for most of the endodontic treatment failure and more prevalent in secondary infections like in Re-rct cases.

4) Citric Acid :
• It causes little enlargement of tubules.
• At 10% concentration, it is more effective as a decalcifying agent compared to 17% conc. EDTA.

5) Some authors recommend using a 95% conc. ETHANOL solution at the end of the canal disinfection phase to create a more dry environment allowing a deeper penetration of endodontic sealer inside dentinal tubules.

• Sequence of Irrigation –

1) In Vital tooth –

5.25%  NaOCl Irrigation atleast for 30 min from start to end  of instrumentation

   ⇓
 Normal saline flush

⇓

17% liquid EDTA 1ml for 1 min for each canal

                           ⇓                           

       Normal saline flush       

⇓

                        5% NaOCl 1 ml for 1 min for each canal followed by drying and obturation

2) In Non-vital tooth –

5% NaOCl Irrigation for 30 min from start to end of instrumentation

  ⇓

      Normal saline flush

 ⇓

1 ml of 17% liquid  EDTA for 1 min for each canal

              ⇓             

        Normal saline flush

                ⇓              

    1 ml of 5%  NaOCl for 1 min for each canal

             ⇓            

       Normal saline flush

     ⇓     

     1 ml of 2% chlorhexidine solution for 2 min for each canal

    ⇓     

     Drying and obturation

3) In open apex –
               
   In open apex cases apical negative pressure Irrigation system is used. Here, syringe on the left is delivering warm 5.25% NaOCl solution through a double side vented 30 guage needle at orifice level and Irrigant is being evacuated by the ‘Luer vaccum tip’ 2 mm short from working length on the right which is then attached to the suction.

• Conclusion :

         The basics of irrigation should be followed as it is more effective and crucial step of endodontic treatment. So many newer techniques are there but what really matters is the activation of irrigants and using proper solutions in proper sequence is more important. For that you can go with any technique whichever is effective for you. I personally use MDA technique as I get good results as you can see in the following x-ray.

• References –

1. Endodontic irrigants : Different methods to improve efficacy and related problems.
Marrio Dioguardi, Giovanni Di Gioia, Gaetano illuzzi, Enrica Laneve, Armando Cocci and Giuseppe Troiano.
‘ European Journal Of Dentistry'

2. New technologies to improve root canal disinfection.
Gianluca Plotino, Teresa Cortese, Nicola M. Grande, Denise P. Leonardi, Gianni DiGiorgio, Luca Testarelli, Gianluca Gambarini.
‘ Brazilian Dent Journal’

3. Effect of sonic versus ultrasonic activation on aqueous solution penetration in root canal dentine.
Damaris  Macias, Victor Bravo and Diego Echeverri.
‘ J Oral Res'

4. Effectiveness of four different final irrigation activation techniques on smear layer removal in curved root canal: A scanning electron microscopy study.
Puneet Ahuja, Suresh Nandini, Suma Ballal, and Natanasabapathy Velmurugan.
‘Journal Of Dentistry Of Tehran University Of Medical Sciences'

5. Review of ultrasonic irrigation in endodontics: Increasing action of irigating solutions.
Sandra Mozu, Carmen Llena, Leopoldo former.
‘ Med Oral Patol Oral Cir Bucal'