Sodium Hypochlorite is being used as the Irrigation of choice in Root Canal Treatment, it is being termed the most potent irrigation solution for Endotontic therapy by Endodotists. Irrigation material is a very important part of the procedure as it helps in killing and disinfecting the Root canal along with removing the debris from the canal and lubricating the walls for proper BMP.

Walker in the year 1936 first used Double Strength Chlorinated Soda (5% NaOCl solution as a root canal irrigant in a Root Canal Procedure he was doing. And after that NaOCl has got great success as a Irrigant Solution. Sodium Hypochlorite has been well recognized as an effective agent against broad range of Pathogens in the Root Canal namely Gram Positive, Gram Negative bacteria, Fungi, Virus and Spores and even reported to kill HIV if present in the root canal.

Properties of Sodium Hypochlorite NaOCl as an Irrigant in Root Canal Therapy: 

  1. Removes the Organic part of the Smear Layer
  2. Excellent Organic Tissue solvent
  3. Very Effective Anti Microbial agent
  4. Good Lubricant
  5. Action starts quickly
  6. Current Irrigant of Chioce
  7. Toxic if comes in contact with periapical tissue
  8. Corrodes and has an Unpleasant Odor to it

Mode of Action of NaOCl:

It acts by 3 types of reaction on the Pulp tissue namely

Neutralization Reaction:

  1. Sodium Hypochlorite acts on the Pulp tissue and it breaks down the Amino Acids in it to form Salt and Water.
  2. NaOCl + Fatty acids –> Salt  + Water (H2O)

Saponification Reaction:

  1. Sodium Hypochlorite acts as an Organic and Fat Solvent degrading Fatty acids
  2. NoOCl + Fatty acids –> Soap + Glycerol

Chloramation Reaction: 

  1. Hypochlorite is responsible for bacterial inactivation.
  2. It must be in direct contact with the bacteria in order to damage the membrane and kill the bacteria
  3. NaOCl + H2O2 –> Na + Hypochlorite + Hypochlorous acid

Factors Affecting the Efficiency of NaOCl:

There are many factors which affect the action of NaOCl in the Root Canal and these factors should be kept under control to get the full effect of NaOCl as a Root Canal Irrigant.

  1. Use of NaOCl in in Full Concentration of 5.52%: This is an important factor which will alter the efficiency in a major way, at lower concentrations some major organisms like E. facalis and Candida Albicans which can enter the Root canal will not be affected and they can only be killed if Sodium Hypochlorite is used at a concentration of 5.25%. so making sure that the solution is not diluted to lose its efficiency is important.
  2. Canal Size and Access: This is another major factor, the size of the canal should be such that the solution can reach the full working length and kill all organisms present in the canal. If the canal is not properly shaped or is too narrow the solution will not reach properly. The access opening should also be properly done to help place the syringe tip into the canal so that the solution can be circulated all through the canal.
  3. Syringe type: The type of syringe used should be with the opening on the side of the needle and not the one with the opening at the tip of the syringe. This will make the solution flow in a way that it will reach all the accessory canals and will not gush out of the apical foramen which can happen in case of normal syringe.
  4. Heating the solution: Slightly Heating the NaOCl solution before irrigation can increase the killing efficiency many times and this has been proved in many studies. Heating the solution to a temperature of 20 and 40 degrees centigrade can bring out the complete killing efficiency of the solution. This can be done by filling the solution in a syringe used to irrigate and keeping it in Hot water bath for sometime to make it warm but not Hot.
  5. Activation with Ultrasonics: Use of Ultrasonic tips to active the irrigation solution increases the efficiency many fold and according to Fabiani the efficiency in the Apical Third of the Root canal has increased a lot on activation with Ultrasonic tips placed inside the root canal after the canal is filled with NaOCl, with activation the solution can reach all the accessory canals as well in the root canal which are major cause in failures of Root canal treatment.

 Sodium Hypochlorite Irrigation Accidents:

When hypo extrudes through the apical foramen and reaches the periapical or peri radicular tissue the patient may experience excruciating pain as we know that NaOCl acts on Tissue by converting the Amino acids present in it into Salt and Water and also degrades the Fat solvents in the tissue which in turn help in necrosis of the tissue with which Hypo has come in contact with.

How to prevent NaOCl accidents while doing RCT: 

Certain precautions should be taken while irrigating with NaOCl as it is as helpful as it is harmful if used improperly.sodium hypochlorite use in root canal treatment

Use Rubber Dam to prevent any spillage on surrounding tissues.

Give the patient protective eye wear

Use rubber stoppers used on files to mark the extent to which the needle tip will be inserted as the needle should be placed 2 mm short of working length

Do not use normal syringe for irrigation but use one with the nozzle placed on the side of the tip to prevent the solution from flowing in to the peri radicaulr tissues.

Do not use excess pressure while injecting the solution but do it slowly and the pressure can push the solution beyond apex.

Do not pus the tip of needle too deep where it gets fixed in the canals and the solution cannot flow out coronaly which will indirectly push the solution out through the apex.

 Treatment of Sodium Hypochlorite Accidents in Root Canal Treatment:

After Sodium Hypochlorite accident main this is to use a lot of Saline to irrigate the canal for 5 to 10 minutes to dilute the concentration of the solution.

Tell the patient and inform him about the possible signs and symptoms which they might experience and convince to patient to be calm.

Give Anti-inflammatory drugs as this will decrease and control the inflammatory process.