2. Chelating Agents
• Chelating agent is defined as a chemical which combines
with a metal to form chelate.
• introduced in dentistry in 1957
• aid in preparation of narrow and tortuous canals to soften the
canal dentin,
• increase dentin permeability and remove smear layer.
3. Mode of action
• It forms Calcium chelate with Ca ion of dentine
• Making dentin more friable
• Easier to instrument
4. Example of chelating agent
Liquid Paste Chelator
Calcinase Calcinase slide
REDTA RC-prep
EDTAC and DTPAC Glyde file
EDTA-T File care EDTA
EGTA HEBP
CDTA
Salvizol
Decal
Tublicid plus
Hypaque
5. EDTA
• Ethylene di amine tetra acetic acid (EDTA) is the most
commonly used chelating agent.
• 15% EDTA has a PH of 7.3
• Composition:
Di-sodium salt of EDTA
Distilled water
Sodium Hydroxide
6. • Collagen is major constituent of vital pulp which can be
packed into glue-like mass which contributes to iatrogenic
blocks. Without the use of a chelator, vital tissue tends to
collapse and re-adheres to itself, but use of chelator does not
allow this phenomenon to occur and accelerate emulsification
of tissue
7. Mode of action of EDTA
• It inhibits growth of bacteria and ultimately destroys them by
starvation because EDTA chelates with the metallic ions in
medium which are needed for growth of microorganisms.
• EDTA has self-limiting action. It forms a stable bond with
calcium and dissolves dentin, but when all chelating ions are
reacted, an equilibrium is reached which prevents further
dissolution
9. Uses
• It has dentin dissolving properties
• It helps in enlarging narrow canals
• Makes easier manipulation of instruments
• Reduces time needed for debridement
10. Advantage
• removes smear layer when used together (but not
simultaneously) with NaOCl by acting on the inorganic
component of the dentin.
• improves the antimicrobial effect of locally used disinfecting
agents in deeper layers of dentine
• Has little antibacterial activity
11. Disadvantage
• complete removal of the smear layer also requires irrigation
with NaOCl before or after citric acid irrigation.
• Anitibiotictal activity is little
• Can’t dissolve pulp tissue
