Sodium hypochlorite is the most widely used endodontic irrigant and contains about 5% available chlorine. It has antimicrobial properties through ionization and acts by penetrating and disrupting bacterial cell walls and DNA synthesis. Concentrations of 0.5-6% are used, with 5.2% being most effective and 2.5-3% commonly employed due to lower toxicity. EDTA is a chelating agent that softens dentin, removes inorganic components of the smear layer, and has no deleterious effects on tissues when used as a 17% final rinse followed by sodium hypochlorite. Chlorhexidine digluconate is a less toxic irrigating

2. ENDODONTIC IRRIGANTS
CLASSIFICATION
(BATCH C)

3. CLASSIFICATION

4. SODIUM HYPOCHLORITE
• Most widely used irrigant.
• Contain about 5% of available chlorine.
Mechanism:
• On ionisation –hypochlorus acid+Hypochlorite ion -responsible for
Antimicrobial activity
• Action: 1) Penetration into bacterial cell wall
2) Chemical combination with protoplasm of bacterial cell and
disruption of DNA synthesis

5. According to Estrella et al., mechanism of action
1. Saponification
2. Amino acid neutralization
3. Chloramination
Properties
1. Concentration
• 0.5- 6 % NaOCl
• 5.2% NaOCl – most effective concentration.
• 2.5- 3% NaOCl – commonly employed as it decreases potential for toxicity.
2. Tissue dissolution ability:
• Dissolves entire pulp in 20 mins to 2 hours –hence useful during cleaning and shaping
of inaccessible areas such as isthmus, accessory canals and C shape canal system.

6. • Chelating agent
Mechanism of action
• Forms calcium chelate solution with calcium ion of dentin- dentin becomes
more friable and easier to instrument.
• Effective in achieving canal patency,enlargement, smear layer removal from
root canal walls.
• Removes inorganic components of endodontic smear layer (smear layer is
combination of dentin, pulpal and bacterial debris produced during
instrumentation).
EDTA-Ethylene Diamine Tetra Acetic acid

7. Effects of EDTA
1. Effective in softening dentin.
2. Removes inorganic part of the smear layer.
3. Extent of demineralization by EDTA is proportional to exposure time.
4. Has no deleterious effects on periodontal cells.
Concentration
17%EDTA used for 1 min as a final rinse followed by NaOCl

8. Chlorhexidine Digluconate (2%)
• Irrigating solution as well as intracanal medicament.
• Less toxic as compared to other irrigants.
Mechanism of action
• Shows broad spectrum antimicrobial activity against common
endodontic pathogens.
• Also possess bacteriostatic and bactericidal activity.
• 2%CHX bind to negatively charged bacterial surface.
It then penetrates the microbial cell wall and cause coagulation
of cytoplasmic components.

9. • CHX is very effective against E.faecalis which is one of the
most commonly identified pathogen in root canal filled teeth
exhibiting clinical failure (retreatment cases).
• CHX most imp c/f : Substantivity
-Property of preventing bacterial colonization of root canal
walls for prolonged period of time.