2. • Diagnosis, Instrumentation, Obturation and Restoration are the main
steps involved in the treatment of teeth with pulpal and periapical
diseases.
• Elimination or significant reduction of irritants and prevention of
recontamination of the root canal after treatment are the essential
elements for successful outcomes.
• In other words, what you take out of a root canal may be more
important than what you put in it.
INTRODUCTION
3. What are IRRITANTS
• The major causes of pulpal and periapical diseases are living and
nonliving irritants.
IRRITANT
MECHANICAL THERMAL CHEMICAL
NON LIVING LIVING
BACTERIA YEAST VIRUSES
MICROORGANISMS
4. • Primary root canal infections are dominated by E. faecalis,
a facultative anaerobic gram-positive coccus that is
-resistant to intracanal medications,
-able to form biofilms
-able to invade dentinal tubules.
• Because the presence of bacteria negatively influences the outcome
of root canal treatment, every effort should be made to eradicate
infections during treatment.
WHICH IS WHY WE NEED IRRIGANTS
http://www.aae.org/specialty/wp-content/uploads/sites/2/2017/07/rootcanalirrigantsdisinfectants.pdf
5. IDEAL PROPERTIES OF AN IRRIGANT:
• Anti microbial activity
• Mechanically flushes out debris from root canals
• Non toxic and biocompatible in nature
• Dissolves necrotic and vital pulp tissue
• Serves as a lubricant
• Removes smear layer
• Has Low surface tension
(A low surface tension should increase the penetration of the mixture into the dentinal tubules,
reducing the bacterial contamination of root canal system )
7. SODIUM HYPOCHLORITE
• Clear, straw coloured solution containing about 5% of available chlorine
• Most widely used irrigating solution
• ionizes > forms hypochlorous acid and hypochlorite ion > anti microbial
activity
• pH is between 11-12
• PHASES of Destruction of bacterial cell wall-
I. Penetration into bacterial cell wall
II. Chemical combination with protoplasm of bacterial cell wall and
disruption of DNA synthesis
8. Mechanism of action occurs in following steps
I. Saponification
II. Amino acid neutralization
III. Chloramination
9. SAPONIFICATION:
Sodium hypochlorite acts as an organic and fat solvent
degrading fatty acids,
transforming them into fatty acid salts (soap) and glycerol (alcohol),
that reduces the surface tension of the remaining solution.
10. AMINO ACID NEUTRALIZATION:
Sodium hypochlorite neutralizes amino acids forming water and salt.
With the exit of hydroxyl ions, there is a reduction of pH.
11. CHLORAMINATION:
Hypochlorous acid, a substance present in sodium hypochlorite solution,
when in contact with organic tissue acts as a solvent,
releases chlorine
that, combined with the protein amino group, forms chloramines.
12. PROPERTIES OF Sodium Hypochlorite
I. Concentration
• No unanimity of opinion exists as to which concentration of NaOCl should be used in RCT
• If Canal is filled with the solution during the entire cleaning and shaping procedure, it will act as a
-lubricant
-solvent of pulp tissue
-potent antimicrobial
• 0.5%-5.2% sodium hypochlorite solution can be used as an irrigant
• Most effective concentration being 5.2%
• 2.5% concentration commonly employed as it decreases the
potential for toxicity while maintaining some tissue dissolving
and anti microbial properties.
[According to Torabinejad et al, during instrumentation
1.3% solution of NaOCl is beneficial as a working solution.]
Extirpated pulp placed in NaOCl solution
And its dissolution
13. II. Tissue Dissolution Ability
• It dissolves an entire pulp in 20 minutes to 2 hours of time
• Some studies show its inefficacy in narrow root canals compared to wide ones
[PASSIVE ULTRASONIC ACTIVATION of irrigant is advocated to increase efficacy as well as enable the
irrigant to reach complex and inaccessible areas such as isthmus areas and C shaped canal system.]
14. MODES OF INCREASING EFFICACY OF SODIUM
HYPOCHLORITE
• Decrease in concentration is safer
but decreases efficacy which can be
compensated by-
• -increasing volume of irrigant
employed
• -Increasing duration of irrigant
employed
• -warming the irrigant > increases
effectiveness (with the help of chair
side irrigant warming devices)
15. Heating the solution
• Instead of using high concentration of NaOCl, the effectiveness
of this solution can be improved by increasing temperature.
• It was confirmed that 1% NaOCl solution at a temperature of
45°C dissolves the same amount of tissue as the concentration
of 5.25% NaOCl at 20°C.
16. ADVANTAGES
• Excellent antimicrobial agent
• Capable of dissolving necrotic tissue, vital pulp tissue, organic
components of dentin and biofilm
• Low viscosity allowing easy introduction into root canals
• Acceptable shelf life
17. DRAWBACKS
• CYTOTOXICITY and
• CAUSTIC EFFECTS
on healthy periradicular tissues on inadvertent extrusion during
irrigating procedure.
(reason for lower concentration being mostly preferred)
• Does not remove inorganic components of endodontic smear layer.
• Has an unpleasant taste
• Solution should be kept in a cool place away from sunlight.
(most common solution used to eliminate the inorganic residues, not removed by NaOCl, is a pH 7 solution of EDTA i.e.
[17%]. 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.)
18. 17% EDTA
(ETHYLENEDIAMINETETRAACETIC ACID)
• A chelating agent, introduced into endodontic practice by
Nygaard-Ostby.
• 17% EDTA is relatively non toxic, only slightly irritating in weak
solutions
• Forms highly stable, soluble metal chelates in combination
with heavy metals or alkaline earth ions.
• Effective in softening dentin
• Irrigation with EDTA removes inorganic part of smear layer
• Extent of demineralization of dentin Is proportional to
exposure time
• EDTA has some deleterious effects when used clinically as
irrigating solution
19. MECHANISM OF ACTION
• EDTA functions by forming calcium-chelate solution with calcium ion of dentin
• Dentin becomes more friable and easier to instrument
HOW TO USE:
• Irrigant employed by depositing a few drops into the pulp chamber with a syringe
and then carefully pumping the solution into root canal with a fine root canal
instrument
• When it is difficult to introduce a file into the canal due to intracanal calcifications
or iatrogenic blockade, then EDTA gel can be used by coating it over the
instrument.
• In case of posterior teeth with narrow root canal, where one risks breaking a fine
instrument, it is better to pump EDTA into the canal and wait for 1 minute before
beginning instrumentation
RECOMMENDED REGIMEN OF IRRIGATION:
EMPLOY 17% EDTA FOR 1 MINUTE AS A FINAL RINSE FOLLOWED BY NaOCl
20. ADVANTAGES AND DRAWBACKS
ADVANTAGES-
• Removes the inorganic part of the smear layer
• Contributes to elimination of bacteria in root canal
• Low toxicity
• When used in combination, has wide spectrum anti microbial activity
DISADVANTAGES-
• Causes demineralization of dentin
• Does not have tissue solvent action
21. CHLORHEXIDINE DIGLUCONATE
• Is a cationic bisguanide which is utilized as an irrigating solution as well as
intracanal medicament
• Relatively less toxic than other irrigating solutions employed
• Structure : 2 symmetrical four-chlorophenyl rings and two bisguanide groups held
together by a central hexamethylene chain
• 2% CHX has better anti microbial activity than 0.12% CHX
22. MECHANISM OF ACTION
• Possesses a broad spectrum antimicrobial activity against most common
endodontic pathogens –
Has ability to permeate microbial cell wall and cause coagulation of cytoplasmic
components
23. ADVANTAGES
• Possesses bacteriostatic and bactericial activity (against gram positive
bacteria and yeast)
• 2% CHX electrostatically binds to negatively charged bacterial surfaces
• Effective against the most common pathogen ENTEROCOCCUS
FAECALIS in root canal-filled teeth exhibiting clinical failure
• MOST IMPORTANT CLINICAL CHARACTERISTIC- SUBSTANTIVITY :
meaning its sustained action in root canal, imparts to its potential of
preventing bacterial colonization for prolonged period of time.
Anti microbial substantivity for upto 12 weeks
24. LIMITATIONS
• Lacks tissue dissolving ability
• Does not remove smear layer and thus has to be employed in
conjunction with other irrigants
(NaOCl and CHX cannot be combined during irrigation procedure as
would cause precipitation reaction.)
25. OTHER IRRIGANTS :
MTAD
• Newly introduced irrigant
• Employs a mixture of tetracycline isomer, citric acid, and detergent
(Tween 80) AS A FINAL RINSE to remove smear layer
• Commonly employed after initial irrigation with 1.3% NaOCl
(New irrigants today used are associated with surfactants, chelators, and
tetracyclines such as Tetraclean®, a mixture of doxycycline hyclate, an acid, and a
detergent.[36,37] It is able to eliminate microorganisms and smear layer in dentinal
tubules of infected root canals with a final 5 min rinse;[20] BioPure MTAD is a
mixture of antibiotic comprising doxycycline hyclate: 150 mg/5 ml (3%), citric acid
(4.25%), and a detergent (0.5%) – polysorbate 80 – or tween 80. It has been
investigated as an effective solution for both removing the smear layer and
disinfecting the root canal system)
-https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089055/
26.
27. CONCLUSION
• The main goal of the root canal treatment is to completely eliminate
the different components of pulpal tissue , bacteria and biofilm and
produce a hermetic seal to prevent infection or reinfection and
promote healing of surrounding tissues
• For optimal irrigation, a combination of different irrigating solutions
must be used
• Developing a rational irrigating solution so that the chemicals are
administered in a proper manner to release their full potential is
imperative for successful endodontic treatment.
