This ppt describes about Irrigation in Endodontics

1. IRRIGATION IN
ENDODONTICS

2. CONTENTS
 Introduction
 Properties Of an Ideal Irrigating Solution
 Functions
 Classification
 Irrigating Solutions
 Overview of Irrigants
 Irrigation Techniques and Devices
 Conclusion

3. INTRODUCTION
 An important objective of endodontic therapy is the
removal of necrotic infected pulp and dentinal debris from
the root canal system of infected or non-vital teeth.
 In order to accomplish this objective, it is essential to
use an irrigating solution or a combination of irrigating
solutions during cleaning & shaping of the root canals.
 Failure to use an irrigating solution during cleaning &
shaping results in considerable amount of debris to be left
behind, blockage of canal in the root canal system
ultimately leading to endodontic failure. Hence for
obtaining an optimum level of disinfection of the root
canal system chemicomechanical preparation is a must.

4. PROPERTIES OF IDEAL SOLUTIONS
 Tissue solvent of both organic material (bacteria and pulp)
and inorganic material (smear layer).
 Sterilization or disinfection (antimicrobial activity).
 Flushing gross debris accumulated during debridement.
 Lubrication of canal to ease instrumentation.
 Low toxicity so as not to harm periradicular and gingival
tissue.
 Low surface tension : This promotes its flow into
inaccessible areas.
 Antiseptic
 Removal of smear layer

5. FUNCTIONS OF IRRIGATION
ANTIMICROBIAL
LUBRICATION
BLEACHING
ACTION
DISSOLUTION &
DEBRIDEMENT
REMOVAL OF
SMEAR
LAYER

6. FACTORS MODIFYING ACTIVITY OF
IRRIGATING SOLUTION
 Concentration
 Contact time
 Presence of organic tissue
 Quantity of irrigant
 Needle – gauge, location, type & systems used along with
needle
 Surface tension of irrigant
 Temperature of irrigant
 Frequency of irrigation
 Level of observation
 Canal diameter/ coarse
 Age of irrigant

7. CLASSIFICATION
 STOCK (based on their chemical activity)
 - Water : Prior to 1940s, water was the most commonly
used endodontic irrigant.
◦ A stream of hot water (140-176oF) were also used.
 Acids : Citric acid and phosphoric acid.
 Alkaline solutions
◦ Sodium hypochlorite (5.25%, 2.6%, 1%, 0.5%).
◦ Sodium hydroxide
◦ Urea
◦ Potassium hydroxide

8.  Oxidative agents
◦ Hydrogen peroxide
◦ Glyoxide
 Chelating agents
◦ EDTA
 Normal saline
 Anaesthetic solution
Combination :
•H2O2 and NaOCl
•Glyoxide and NaOCl
•RC prep and NaOCl

9. CHOICE OF AN IRRIGANT
Currently, there is no single irrigant that can fulfill
all the requirements, so we have to rely on their
combinations to fulfill the requirements.

10. HOT WATER
 A stream of hot water, 140-178°F discharged from an
insulated syringe was the first irrigant used.
 Used for flushing of the root canals.
 Studies performed in 1955 by Lorixzy et al showed peri-
apical bone regeneration after mechanical instrumentation
using water as an irrigating solution.

11. NORMAL SALINE
 0.9% w/v, pH-7, commonly used irrigant in
endodontics
 Primary flushing action
 Mild action, can be used as an adjunct
 Can also be used as a final rinse

12. Advantages: Disadvantages:
 Very bio-friendly
 No adverse reaction if
extruded because of the
osmotic pressure of
normal saline is same as
that of the body fluid.
 Absent antimicrobial property
(however irrigation followed by
ultrasonic and sonic
instrumentation have been
reported to be almost as effective
as 0.5 to 2.5% NaOCl irrigation)
 Incapable of removing smear
layer
 Do not possess dissolution and
disinfecting properties
 Cannot clear microbial flora
from inaccessible areas like
accessory canals.

13. SODIUM HYPOCHLORITE
 One of the most popular irrigating solutions.
 It is clear, pale, green-yellow proteolytic, reducing agent with strong
odor of chlorine. It is miscible with water and gets decomposed by
light.
 1st recommended as an antiseptic solution by HENRY DAKIN in
1915 during the time of World War-I. It also known as DAKIN’s
SOLUTION – 0.5% concentration --- used for treatment of infected
wounds.
 It is highly alkaline with PH of 11.0-11.5(NaOCl buffered with sodium
bicarbonate).
 5% of available chlorine (Grossman)

14.  Commercially available Chlorox (pH 10.83 – 10.98)
Composition : NaOCl 5.25%
Na2CO3 0.20 %
NaCl 4.0 %
NaOH 0.005 – 0.015%
H2O 90%

15. MANUFACTURING
Two methods:
 1.Cl2 + 2NaOH NaOCl + H2O +NaCl
 2.Electrolysis of saturated brine solution to produce
Na+ & Cl- ions

16. STORAGE & HANDLING
 Store in light proof (opaque glass / polyethylene)
 Stability of NaOCl is reduced by -
 Lower pH
 Presence of metallic ions
 Exposure to light
 Open containers
 High temperatures

17. PROPERTIES OF NaOCl
Antibacterial
action
Strong
dissolution
property
Lubricant
Bleaching
action on
discolored
teeth
Increased
permeability
of dentinal
tubules

18. MECHANISM OF ACTION
 Sodium hypochlorite exhibits a dynamic balance
as shown by the following reaction:
 NaOCl + H2O ↔ NaOH + HOCl ↔ Na+ +OH-+H+ + Ocl
In water, NaOCl ionizes to produce Na+ and the hypochlorite ion, OCl - ,
that establishes equilibrium with hypochlorus acid, HOCl.
Between pH 4 and 7, chlorine exists in equilibrium predominently as
HClO(molecular formula for hypochlorus acid), the active moiety,
where as above pH 9 , OCl- ion is less effective than undissolved
HOCl.
Hypochlorus acid disrupts oxidation phosphorylation and other
membrane-associated activities as well as DNA synthesis.

19. SOLVENT ACTION OF NaOCl
◦ Grossman & Meiman – more effective pulp solvent
than KOH, H2SO4, NaOH, HCl and Papain
◦ 2.5% solution – powerful solubilizer – Koskinen et
al
◦ Morgan et al – 80% tissue solvency – 2.6%
solution

20. ANTIMICROBIAL EFFICIENCY
 1% NaOCl has found to kill both bacterial spores and
HIV over a period of 30 minutes.
 Sen et al – 1 & 5% NaOCl effective against C.albicans.
 Ohara et al – 1/10 concentrations of NaOCl effective
against several anaerobic bacteria. However dilution below
1/10 was completely ineffective.
 Kuruvilla & Kamath – 50% reduction in microbial count
– 2.5% NaOCl, synergistic response with CHX (0.2%) lead
to 80% reduction in microbial count.

21. TIME REQURED FOR ANTIMICROBIAL
EFFECT
 In presence of smear layer – 1 hour (samples at 1minute, 5minutes & 30
minutes were positive).
 If smear layer was removed, 5% NaOCl complete antimicrobial activity
◦ At 15 & 30 Min Intervals NaOCl found to clear the coronal & middle
third of the canal better than saline. However in apical 3mm no
difference was seen.
◦ NaOCl more effective in large diameter canals.
◦ More effective in cleaning an isthmus.
◦ Zeev – ram – removal of debris is dependent on canal diameter,
pressure of irrigation & diameter of irrigating needle. (reported least
diameter no. 40)
◦ Marvan Abon – Rass - least diameter no.25 to be effective

22. EFFECT OF TEMPERATURE
 Collagen dissolving effect
 Cunningham & Balekijan showed that increasing the
temperature from 220C-370C of a 2.6% NaOCl solution
increased its tissue dissolving properties which were equivalent to
those of 5.25% solution at room temperature.
 Bactericidal effect:
 Was shown that for warmed 2.6% solution against E.Coli,
S.Sanguis, B.Subtilis spores, P.Vulgaris, S.Aureus organisms as
early as 45 secs. (Cunningham & Joseph) .The spores took the
longest time - 180 secs. (compared to 600 secs for solution at 22 0C)
 Ellerburch & Murphy demonstrated that even vapors of NaOCl
exert strong bactericidal action.

23. EFFECT OF SURFACTANTS ON SODIUM
HYPOCHLORITE
 Senia, Marshall & Rosen, Salzgeber & Brilliant, and Ram ---- that little or
no spreading of the irrigant occurs in canals that are smaller than file
size No.40. A reduction in surface tension would allow for a more
intimate contact between the irrigant and the root canal system.
 Abou – Rass & Patonai --- lowered surface tension (79.6 to 69.8 mN/M for
5.25% NaOCI) when Polysorbate 80 was used.
 Cunningham & Associates --- Ethyl alcohol
 Cameron --- fluorocarbon surfactant, Fluorad FC 99

24. Ultrasonic activation of sodium
hypochlorite:
 Ultrasonic activation of NaOCl has shown to
accelerate chemical reaction, create cavitational
effect and thus achieve a superior cleansing action.

25. Effect of NaOCl on the composition and
structure of dentine
 NaOCl-treated dentine samples demonstrated a slow
and heterogeneous removal of its organic phase,
leaving calcium hydroxyapatite and carbonate apatite
unchanged.
 5% NaOCl --- alterations in dentine collagen and
glycosaminoglycans and hydroxyapatite.
 NaOCl causes a concentration-dependent reduction
of elastic modulus and flexural strength in human
root dentine.

26. Effect of NaOCl on bonding to dentine
 Increase in the NaOCl application time resulted in a
progressive decrease in shear bond strengths for both
dentine adhesives.
 After hypochlorite treatment, dentine bond
strength and marginal adaptation decreased
significantly.
 Shinohara et al. found that depending on the adhesive
system used, the application of NaOCl increased
microleakage along dentine margins

27. Penetration into dentinal tubules
 Higher the concentration beter is the
penetration in dentinal tubules.
 Shortest penetration (77 mm) was
measured after incubation with 1% NaOCl for
2 minutes at room temperature.
 The highest penetration (300 mm) was
obtained with 6% NaOCl for 20 minutes at
45C.

28. Specialized irrigating syringes
 Newer specialized side venting endodontic syringes
with narrow diameter (32 gauge) are available which
aid in getting irrigant closer to apex and help the
irrigant to move sideways.

29. ADVERSE EFECTS OF SODIUM
HYPOCHLORITE
 1. SODIUM HYPOCHLORITE ACCIDENT:
 The inadvertent injection of NaOCI into the soft tissues
can elicit a violent and frightening response.
 The cause of this emergency can be related to both the
irrigant and the irrigant technique (Wedged needle with
forceful irrigation).
 Mechanism from injury is primary oxidation of proteins
followed by inflammatory reaction from the body.
 This response is similar to that proposed in Angioneurotic
edema with release of Histamine or histamine like
substance, a vasodilatation with subsequent transudation of
plasma accompanied by hemorrhage.

30.  The amount of tissue destruction depends on:
◦ Host response
◦ Volume of irrigation
◦ Concentration irrigant
◦ Temperature of irrigant
◦ Spread of solution
 Sequence of Events: (Sabala & Powell)
 Excruciating pain within 2-5 min
 Burning sensation in affected area
 Immediate swelling (ballooning) of the tissue in the area with spread
to surrounding loose connective tissue.
 Profuse bleeding episode either interstitially or through the root canal
system.
 Over the next few days, the pain subsides to a constant discomfort,
swelling persists over a week and progressively subsides.
 The interstitial hemorrhage may result in echymosis over the skin
because of which the affected skin is discolored.

31. Treatment Modality
 Stop treatment and give an explanation to the patient- Remain Calm Reassure
patient.
 There is no antidote per se for NaOCI, therefore resort to palliative care
 Immediately irrigate with copious amounts of saline
 Evaluate airway
 Pain control
◦ Immediately with a nerve block
◦ Prescribe analgesics
◦ ( Naproxen in a dosage of 500-1000mg/day sufficient)
 Corticosteroids for 3 days.
◦ Ist dose I.V. Reeh & Messer HH recommend 4-48 mg/ day Triamcinolone
◦ 8mg Doxona I.M. would also suffice).

32.  Consider incision and trephination if deemed necessary
 Antibiotics for 1 week (Becker, Cohen, Borer)
◦ Prophylactic: Penicillin & Metronidazole
 Cold compresses for first 6 hours followed by warm compresses and
mouth rinses – 1 week.
 Provide verbal and written home care
 Set up regular recall visits

33. PREVENTION
 Prevention of inadvertent extrusion of irrigant past apex. Measures
include:
 Express intra canal irrigant slowely
 Passive needle placement in canal (especially if beveled)
 Watch for flow back of irrigant
 Procedure to be performed under Rubber Dam

34. HYPERSENSITIVITY TO NaOCl
 History is important, can be followed up with a patch
test for confirmation
 Adverse effects cannot only be related to Clinical
Toxicity (Harrison) but also to Allerginicity.
 In such patients, use alternative solutions like Solvidont.

35. HYDROGEN PEROXIDE
 1943, Grossman introduced 3% Hydrogen peroxide as an
Endodontic irrigant
 Ohara, Torabinejab & Kettring--- evaluated 3% H2O2 to other
contemporary irrigants w.r.t. it’s anti-microbial efficiency and found it
to be moderate to the anaerobic pathogens.

36. NaOCl + H2O2
 Produced a transient but energetic effervescence ---
production of nascent oxygen
 Responsible for forcing debris and microorganism out of the
canal
 H2O2 does not posses tissue dissolving properties, nor is it a
lubricant. Limited antimicrobial action only.
 Coupled with the solvent action of NaOCI on the organic
debris.

37. ◦ This was the coupled with the solvent action of NaOCI on the organic
debris.
◦ Baumgartner and Ibay have explained the stoichiometric basis for the
interaction between NaOCI and H2O2 which is summarized as follows:
2NaOCI + H2O2 O2 + CI2 + 2NaOH
2NaOH + CI2 NaCI + NaOCI + H2O2
◦ No chlorine is actually available at the end of these reactions therefore
the bactericidal activity of this combination is questionable.
◦ The combination has been shown to inhibit individual antibacterial
properties
◦ When irrigating with H2O2 the last irrigant used should be NaOCI to
prevent any nascent oxygen from being trapped in the canal.

38. ◦ Adverse Sequelae:
◦ Nahlieli & Neder in Israel reported a case of Iatrogenic Penumo-
Mediastinum after irrigation with hydrogen peroxide.
◦ Such a patient may present with pain, dyspnoea, fever,
leukocytosis and swelling CXR is advised.
◦ Prophylactic antibiotics – 10days
◦ Monitoring of patient’s vitals
 Air emphysema - symptoms of sudden, severe pain accompanied by
a rapid swelling, crepitus and erythema in the region of the treated
tooth
 In most cases emphysema during root canal treatment does not
require antibiotics or any other therapy; the emphysema in most
cases resolves after few days

39. CHELATING AGENTS
 Nygaard - Ostby in 1957 introduced EDTA
 EDTA is an insoluble, odorless, crystalline white powder; it is
relatively non toxic & only slightly irritating in weak solutions.
 pH 8.3, Concentration -17%
 Has dentin dissolving effects desirable in all kinds of RC therapy
 Reduced the time necessary for debridement
 Aided in enlarging narrow/ obstructed canals
 Helped bypass fragmented instruments
 Not corrosive on instruments
 Antimicrobial – neither bactericidal nor bacteriostatic

40.  Self Limiting Action:
◦ EDTA forms a stable bond with calcium & the
deposited solution can dissolve only a certain amount of
dentin
◦ When all chelating ions have reacted, an equilibrium
will be reached; then no further dissolution will takes
place.
◦ This effect was found to be rapid during first one hour
and reached equilibrium by the end of seven hours.
Functions of EDTA:
Lubrication/Emulsification
Smear Layer removal

41.  EDTA has been dispensed in two forms – Viscous and
Aqueous.
 A viscous product is used for the lubrication and smear
layer removal/dentin dissolving during canal preparation
whereas the aqueous solution is used as a final flush after
shaping and cleaning for smear layer removal.

42. Antimicrobial effect
 17% EDTA solution possess significantly better antibacterial
properties as compared to saline.
 Ohara, Torabinejad & Kettering found the solution to be of
antibacterial benefit after 60min - 1 week of exposure to bacteria. At
the same time, exposure times of such magnitude may not be practical
clinically. For P.gingivalis, the solution had good antibacterial effects.
 However, other authors have proven that EDTA possesses at best, a
limited antibacterial activity.
 Antifungal Activity
 Because EDTA chelates to Ca2+ it prevents binding of C.albicans to
proteins in a dose dependent manner.
 It removes Ca2+ from the cell walls & thereby causes the cell walls to
collapse.
 Also inhibits enzymatic reactions

43. EDTA & SMEAR LAYER
 Effective in removing smear layer from the coronal aspect --- failed
to do so from the apical third (Ram).
 Stewart & others introduced a combination of EDTA & urea
peroxide in a base of carbowax which was termed RC-prep.
 Later on, the composition of RC-prep was changed to replace urea
peroxide by 15% carbamide peroxide.
 Goldman et al showed that NaOCI was incapable of removing the
smear layer while REDTA (EDTA + cetrimide) cleaned the canals
effectively of inorganic portions with organic material being left
behind.

44. MECHANISM OF ACTION
NaOOCCH2 CH2CHOOH
N CH2 CH2 N
HOOCCH2 CH2COONa
+
2NaOCI
+
2HOCI
NaOOCCH2 CH2COONa
N CH2 CH2 N
NaODCCH2 CH2COONa

45.  Second step accounts for effervescence
4HOCI 2CI2 +O2+ 2H2O
 Suggested 10ml of EDTA 17% followed by 10ml of NaOCI for
effervecent action.
 This combination has served an endodontist as a gold standard
irrigant for almost the past two and a half decades and meets nearly
all the requirements of an ideal irrigant used while shaping and
cleaning the root canal.
 Goldberg & Abramovich added a quaternary ammonium bromide-
Cetavlon to EDTA to reduce it’s surface tension & was called
EDTAC. This addition increased the wetting effect on the canal walls
& permitted deeper penetration into the tubular irregularities.

46.  EDTA-T (with sodium lauryl sulfate) was similarity introduced
 Aktener & Bilkay developed a solution of EDTA & Ethylenediamine (a
strong organic solvent). They found several patent tubules in the coronal
third portion & concluded that more research was needed to evaluate the
efficiency of this combination.

47. DEMINERALIZING EFFICIENCY OF EDTA
 Cury, Bragotto & Valdriht evaluated the demineralizing efficiency
of EDTA at different pH values & found that a 0.3M solution
showed greatest demineralizing efficiency between pH of 5-6.
 It may imply that the intertubular dentin completely disappears
between tubules combining individual tubule openings in close
proximity.
 A 1 minute application however removed the smear layer without
inappropriate erosion.
 A related chelator EGTA - Ethylene glycol-bis-( aminoethy1 ether)
N,N,N1, N1, Tetraacetic acid was introduced & reported by Calt &
Serper to have effective smear layer removal without inducing
dentinal erosion caused by EDTA.

48. TIME & DEMINERALIZATION
 EDTA has been reported to remove smear layer in < 1 minute if it is able
to reach the root canal surface
 Since EDTA has a strong demineralizing effect, it caused
◦ Enlargement of the dentinal tubules
◦ Softening of the dentin
◦ Denaturation of collagen fibers.
 This may affect the adaptation of the root canal filling materials to the
canal wall
 Yamada reported a few seconds of EDTA to be sufficient whereas
Goldberg & Spielberg reported an optimum time of fifteen minutes.
 Calt & Serper showed that a ten minute application caused severe
peritubular & intertubular erosion. Because of more erosion, the
diameter of the openings are greater than the tubules themselves – known
as WORMHOLE APPERANCE

49. BOND STRENGTHS TO TREATED DENTIN
 A treatment with 5% NaOCI & R C Prep produces a significantly
large reduction in bond strengths in dentin.
 1. NaOCI: Oxidizing action of this agent leads to the oxidation of
the dentin matrix that is critical during composite polymerization
 2. RC-prep: Residual peroxide breaks down to produce oxygen &
water
◦ These form bubbles or voids which interfere with resin
infiltration into etched dentin
◦ Oxygen is a known inhibitor of polymerization
 The peroxide may also oxidize collagen or other matrix components
therefore interfering with interfacial polymerization. Polyethylene
Glycol residues prevent complete polymerization of monomers to
polymer. Therefore use of 10% Ascorbic acid/ sodium ascorbate is
recommended. Polyethylene Glycol residues prevent complete
polymerization of resin by converting the oxidized substrate to a
reduced substrate thereby restoring the redox potential of dentin.

50. EDTA + CHX
 EDTA + CHX (chlorhexidine)
 Immediate formation white foggy precipitate
 Precipitate involves chemical degradation of
chlorhexidine.

51. TANNIC ACID
 Tannic Acid 25% as a cleansing agent in endodontics was first
suggested by Graham Mount.
 It has ASTRINGENT PROPERTIES for coagulation by
precipitation of proteins.
 It is also known to possess antimicrobial properties.
 No deleterious pulpal reactions have been found in Tanin-Fluoride
preparations (Tanizaki & Inoue).
 It caused an increase in dentin hardness because of it’s inhibiting
effect on calcium dissolution while the organic matter in dentin was
reinforced. Constriction & obliteration of dentinal tubules has been
observed & dissolution of organic matter was inhibited. (Tanizaki
& Inoue).

52. CITRIC ACID
 A 50% Citric Acid solution possesses antimicrobial efficacy equivalent of
5.25% NaOCI against several anaerobic bacteria.
 Use 10ml for a duration of 5min-15min
 A combination of citric acid & NaOCI has also been demonstrated for it’s
antimicrobial properties (Baumgartner & Ibay 1987 JOE). Loel described
the foaming action which occurred on the addition of NaOCI to 50%
Citric Acid.
 As Citric Acid is very acidic (pH=1.28), the initial reaction readily occurs
to yield a large amount of HOCl which decomposes to form Cl gas.
 It removed smear layer from both middle & apical thirds of the canal
 Was equally effective for smear layer removal as was 17% EDTA

53. TETRACYCLINE
 Includes:
◦ Tetracycline HCI
◦ Minocycline
◦ Doxycycline
 Are broad spectrum antibiotics effective against a wide range of micro-organisms.
Known to enhance healing after surgical periodontal therapy.
 Low pH in concentrated solutions & thus can act as calcium chelators. This may
cause root surface demineralization comparable to citric acid.
 Substantivity of these antibiotics allows them to be absorbed & released gradually
from tooth structures.
 Ability to remove smear layer also studied.
 Doxycycline HCI (100mg/ml) effective in removing smear layer of instrumented
canals. 1% Tetracycline HCI could remove the smear as efficiency as 50% citric
but was found to retain the peritubular architecture of dentin.

54. CHLORHEXIDENE
• It is a cationic bis-biguanide with optimal antimicrobial action
between pH 5.5-7.0 (Leonardo et al)
• Concentrations of use of Chlorhexidene :
• Include 0.12%, 0.2% & 2% (Hays, Janer & White)
• A commercially available oral rinse typically contains 0.12%
Chlorhexidene gluconate, 11.6% alcohol, glycerin, flavoring agents,
saccharin.
 ANTIMICROBIAL ACTIVITY:
 Possesses a broad spectrum against gram positive & gram negative
bacteria fungi, bacteria spores, lipophyllic virus, dermatophytes

55. Mechanism of Action –
◦ High Concentrations: Bactericidal - It penetrates the cell wall & causes
precipitation or coagulation of cytoplasm probably caused by cross- linking.
◦ Low Concentrations: Bacteriostatic - Positively charged molecules of CHX
bind readily to the negatively charged cell wall, mainly to phosphate groups
in LPS, & carboxyl groups in proteins. It therefore interferes with
membrane transport initialing a leakage of low molecular weight
substances.
 Acts by adsorbing into the cell walls of the micro-organisms & causing leakage
of intracellular components.
 Bacteriostatic effect is considered to be more important since the bound
chlorhexidene molecule is released slowly over 24 hours.

56.  When 2% & 0.2% each of NaOCI &Chlorhexidene were compared - Both showed
equivalent antimicrobial effect.
 CHX is a base, capable of forming salts of a number of organic acids.
 NaOCI – oxidizing agent: Oxidizes gluconate part of Chlorhexidene gluconate to
gluconic acid.
 The CI- groups may get added into the guanidine component of the chlorhexidene
molecule forming Chlorhexidene-CI
Results in increasing ionizing capacity of Chlorhexidene
Makes solution more alkaline
◦ CHX – 6.5pH
◦ NaOCI-9 pH
◦ combination- 10
 Has effective action against E. facealis

57.  Buck & others have reported on the ability of a combination of
Chlorhexidene , NaOCI & alcohol to detoxify LPS molecules by
hydrolysis within the canal.
 Heating of Chlorhexidene solution to 460C enhanced the antimicrobial
action of 0.12% Chlorhexidene and produced a 1.8 log reduction of E.
faecalis.
 Evaluation of the antifungal properties revealed these solutions to perform
as well as routine antifungal agents like Nystatin & Ketoconazole & found
superior results to 5.25% NaOCI

58. ANTIMICROBIAL SUBSTANTIVITY
 Root canals treated with Chlorhexidene result in the molecule being adsorbed
into dentin.
 Root dentin treated with Chlorhexidene has shown to acquire substantivity,
which extends to at least a period of 7 days. (upto 12 weeks)
 Antimicrobial substantivity acquired by the root dentin after treatment with
Chlorhexidene could inhibit re-infection of the canal subsequent to treatment.
 Antimicrobial substantivity depends on the number of CHX molecules
available to interact with the dentine. Therefore, medicating the canal with
more concentrated CHX preparation should result in increased resistance to
microbial colonization.

59.  TISSUE DISSOLUTION PROPERTY
 It does not posses any tissue solvent property (Naenni,
Thoma & Zehnder)
 TOXICITY
• Characterized by a relative absence of toxicity (Lee, Lan,
Wang)
• Yesilsoy et al through their animal experiment demonstrated
a moderate intensity foreign body reactions.
• Jeansonne & White also reported it’s non toxicity &
suggested its use in cases of perforations, open apices or
difficult isolation cases.

60. Interaction of CHX & NaOCl
 Immediate formation of brown precipitate --- para-
chloroaniline(PCA)
 Tends to occlude dentinal tubules
 PCA directly increased with increase in NaOCl
 Toxic in humans with short-term exposure, resulting in cyanosis,
which is a manifestation of methemoglobin formation.
 The combination of NaOCl and CHX causes color changes and
formation of a possibly toxic insoluble precipitate that may
interfere with the seal of the root obturation.
 Alternatively, the canal can be dried using paper points before the
final CHX rinse OR by using absolute alcohol or minimized by
using saline as intermediate irrigant.

61. IODINES
 Two iodine preparations are in use as endodontic irrigants
 Povidone iodine ( Betadine) – 10%
 Iodine Potassium Iodide 2%
 Betadine scrub is also available which incorporates a
surfactant. Torneck advocated the use of Povidone – Iodine
solution because of
◦ Rapid antiseptic action against a wide range of micro –
organisms- Performs better in antibacterial efficiency as
compared to Ca (OH)2.
◦ IKI achieved 100% sterility is 15 min time frame
◦ Low toxicity
◦ Hypo-allerginicity
◦ Decreased tendency to stain dentin as compared to other
iodine containing antiseptics

62. Mechanism of Action –
 Iodine is strong oxidizing agent. It reacts with free sulfhydryl
groups of bacterial enzymes resulting in disulfide linkages.
Therefore effective against several root canal microbes.
 Also found to have lower toxicity to tissue culture cells at 2%
concentration compared to other intracanal medicaments except
Ca(OH) 2.
 Its antimicrobial effect is due to its vapour forming ability and low
surface tension.

63. SALVIZOL
 Derivatives of oxine (8 hydroxy quinolone) and have action
against bacteria, fungi & molds. Used in dentistry in 1956
first by Trotter for post extraction infections.
 Salvizol belongs to the surface acting materials similar to
the quaternary Ammonium group. It differs from the latter
by it’s anti bacterial activity even in the presence of
organic materials.
 Material is well tolerated by PDL tissues.
 Root canals treated with 0.5% Dequalinium solution were
cleaner than those treated with 15% EDTA (Kaufman).
Because of it’s detergent properties, it can penetrate into
places that cannot be reached by instruments.
 It removes organic material from dentin material & to a
lesser extent inorganic portions
 Effective even in apical 1/3rd of canal.

64.  A related compound Bis-Dequalinium Acetate (BDA)
marked as -
SOLVIDONT
◦ Less antimicrobial & more cytotoxic than IKI
◦ Cytotoxicity – antimicrobial quotient higher than NaOCI.
◦ It’s ability to remove smear layer was no different than
NaOCl or saline except for slightly enhanced action in
apical 1/3 rd of root canal.
 Dispensing forms: -
◦ Irrigation solution – 0.125 %
◦ Working solution – 0.5%
◦ Paste – 0.48%

65. Electrochemically Activated Water
ECA solutions are produced from
tap water
low concentration salt
solutions.
 When electrolysis of an
aqueous saline solution is
carried out in an EAW unit, an
anolyte and a catholyte of
electrochemically activated
water are produced and
isolated.
 Active state - 48 hrs (before
the solution reaches its stable
state becoming inactive once
more)

66.  The anolyte has a high-oxidation potential (400-
1200mV) and is antimicrobial, and pH of between 2 and
9.
 Catholyte is an alkaline solution with a high-reduction
potential (200-900mV) and is reputed to have a strong
cleaning or detergent effect.
 When the anolyte and catholyte were individually used
to irrigate infected canals, the antimicrobial
effectiveness was disappointing when compared with
0.5% sodium hypochlorite.
 Commercial product - Sterilox (Optident,
Peterborough,UK)
- Anolyte (Sterilox solution), Catholyte (sodium
hydroxide pH 12.5)

67. OXIDISED POTENTIAL WATER
 Hata et al studied new antibacterial and antiviral agent
for root canal irrigation. Oxidative potiential was
developed in Japan for household and agricultural
disinfecting purposes
 Defined as an electrolytically obtained highly acid water
having accumulated in the anode compartment after
sodium chloride added water has consumed OH ions
 OPW is strongly acidic with a pH of 2.5
 It’s oxidation – reduction potential is 1050 m V as against
300 m V for tap water
 Possesses several oxygen containing antimicrobial
constituents like HOCI and O3
-

68.  Shimizu reported killing of viruses which
include HSV, HIV and Mouse CMV.
◦ Absence of toxicity & irritability caused by immediate
loss of high oxidation reduction potential and low pH
upon reacting with light and for organic substances.
◦ OPW is safe for patients to hold in oral cavity
◦ Volume for use –10ml . Time -> 1 min
◦ Does not effectively remove smear layer (Serper &
colleagues)

69. Ozone in Endodontics
 What is Ozone??
 Ozone is a form of oxygen created by the combination
of oxygen in air with the ultraviolet rays of the sun. It
acts as a filter layer in our atmosphere to keep out
harmful electro-magnetic radiation. Viruses and fungi
are killed by ozone instantaneously -- it is nature's own
purifier

70. MECHANISM OF ACTION
 It works by breaking up the cell walls of bacteria,
viruses or fungi.

71. OZONATED WATER
 Ozonated water is powerful antimicrobial agent against
bacteria, fungi protoza and viruses.
 Ozone in aqueous or gaseous phases has a strong
oxidizing power with reliable microbial effects
a) Ozone destroys cell walls & cytoplasmic membranes of
bacteria & fungi
b) Increased permeability leads to ingress of ozone which cause
microbial death.
 Advantages:
◦ Potency
◦ Ease of handing
◦ Lack of mutagenicity
◦ Rapid microbial effects
◦ Showed lesser toxicity to L929 mouse fibroblasts than
NaOCI. (Nagayoshi et al)
 Disadvantages:
◦ Requires continuous flow for it’s action.
◦ Rapid ozone degradation in contacting organic compounds.

72. ENDOQUIL
 Endoquil is a natural product derived from a tropical plant
Ricinus communis, a castor oil detergent.
 Fereira et al used endoquil & 0.5% NaOCI as irrigants &
found the former to reduce CFU’s for anaerobic organisms
better in teeth with necrosis & periapical lesions. Effective
against gram +ve organisms only (Leonardo et al)
 MOA: Acts on the biofilm of adherence between canal wall
& bacteria.

73. GLUTERALDEHYDE
 Investigated as an irrigant because of germicidal
activity.
 However, is also capable of producing inflammation
 Martin found 2% glutaraldehyde to produce extensive
necrosis with only mild necrosis for 5% NaOCI.
Therefore it has never become popular as an irrigant.

74. MTAD
 Introduced to scientific literature in 2000, this irrigant was
introduced by Torabinejad et al at the Loma Linda Dental
School.
 It is composed of a mixture of
A) Tetracycline: 3% Doxycycline hyclate
i) Broad spectrum antibiotic - Bacteriostatic in nature.
ii) Low pH
iii) Calcium chelator - Surface demineralization similar to citric
acid
iv) Substantive property
v) Promotes healing
vi) Removes smear layer
B) Citric Acid (0.5%) – also removes smear layer, Bactericidal
C) Detergent – Tween 80, decreases surface tension.

75. MTAD AND SMEAR LAYER (2min application, 5ml volume)
 Although MTAD removes most of the smear layer some remnants of the organic
component are scattered on root canal wall surface. It effectively removes the smear
layer with less erosion to dental structure than EDTA.
It produces no adverse effects on flexural strength and modulus of elasticity
of dentin.
ANTIMICROBIAL EFFECT
 MTAD appears to be more effective than 5.25% NaOCI in disinfecting root canals
after the removal of the smear layer. Highly effective against E. faecalis after a
relatively short exposure time of two to five minutes.
The protocol for clinical use of MTAD is 2 minutes with 1.3 percent NaOCl followed
by 2 minutes of MTAD.
 Has the capability kill E. faecalis even at dilutions of 200 X whereas for NaOCI, this
was restricted to a dilution of 32X
SOLUBILIZING ACTION:
 Lesser than NaOCI but similar to EDTA

76. CYTOTOXICITY:
 Less cytotoxic than Eugenol, 3% H2O2, Ca(OH)2 paste, 5.25%
NaOCI, Peridex & EDTA but more cytotoxic than 2.63%, 1.31% &
0.66% NaOCI.
 No effect on flexural strength, modulus of elasticity of dentine
TETRACLEAN – another combination product similar to MTAD.
The differences are – Doxycycline hyclate - 50mg/5ml (MTAD –
150mg/ml)
Detergent – Propylene Glycol (MTAD – Tween 80)

77. RUDDLE’S SOLUTION
 This solution is based on the use of HYPAQUE – M, a radio-
opaque, high contrast injectible dye.
 5% Sodium Hypochlorite + Hypaque M + 17% EDTA
 Solvent action and ( radio-opacity similar to Gutta Percha)
because of Hypaque
 Penetration because the tensioactive agent decreases the
surface tension besides removing the smear layer
 Solvent action of NaOCl + improved penetration due to
EDTA + radiopacity due to Hypaque – Used to detect the
presence of lateral/accessory canals.
 NOT used as an irrigating solution.

78. PARAMETERS FOR EVALUATING THE
EFFICACY OF AN IRRIGANT
 Volume
 Concentration
 Surface tension
 Canal anatomy
 Working time
 Temperature of solution
 Depth of penetration
 Method of delivery of solution

80. THE NEEDLE & SYRINGE
 a syringe and needle allows exact placement, replenishing
of existing fluid, rinsing out of larger debris particles, as
well as allowing direct contact to microorganisms in areas
close to the needle tip.
 In passive syringe irrigation, the actual exchange of
irrigant is restricted to 1 to 1.5 mm apical to the
needle tip, with fluid dynamics taking place near the
needle outlet.
 Volume and speed of fluid flow are proportional to the
cleansing efficiency inside a root canal.
 Diameter and position of the needle outlet determine
successful chemomechanical debridement -- placement
close to working length is required to guarantee fluid
exchange at the apical portion of the canal, but close
control is required to avoid extrusion.

81.  Excess pressure or binding of needles into
canals during irrigation with no possibility of
backflow of the irrigant should be avoided under
all circumstances to prevent extrusion into
periapical spaces.
 In immature teeth with wide apical foramina
or when the apical constriction no longer exists,
special care must be taken to prevent irrigation
extrusion and potential accidents.
 There are different sizes and types of irrigation
needles.
 The size of the irrigation needle should be
chosen depending on the canal size and taper.

82. Gauge of the needle:
◦ Gauges ranging from standard 22 gauge to the finer 30
gauge needles were ineffective for endodontic irrigation.
◦ Since irrigation of apical third requires the needle to be in
it’s proximity for adequate effect (Ram), Abou-Rass &
Piccinino, the canals contents should be flushed with a 27-
30 gauge needle placed in apical third.
◦ However Senia, Marshall & Rosen pointed out that in fine
needles, NaOCI could be deposited as crystals. This would
obstruct the needle & require more force

83. 2. The needle should be bent to an obtuse angle to
allow for easier access & entry to the orifice. This
bend is to be placed closer to the hub of the syringe.
3. Designs of Needles:
◦ a) Open ended blunt needles
◦ b) Beveled needles
◦ c) Blunt ended side venting needle (ProRinse)
◦ d) Notched tip (Monojet – 27 gauge) – allows backflow and
doesn’t not create pressure in the periapical area
◦ e) Perforated needle –Endovage (Goldman & others)

85.  The effective canal clearance seen in the Pro- rinse system is
attributed to it’s tip design with the lumen being 2mm from the
tip. This creates turbulence along & beyond the probe. This also
prevents forceful periapical injection of irrigant
 Disadv – Too much force required. (Moser & Hener – 14lbs)
 Goldman & others advocated clearer canals with a perforated
needle system (introduced by them in 1976). However Moser &
Hener revealed that these needles fractured even if slightly bent.
 Recent Innovation: Stropko Irrigator this irrigation system
combines the delivery & recovery of irrigant in one probe. The
needle delivers the solution and an aspirator held in the same
sheath retrieves the delivered irrigant.

86. TECHNIQUE
1. Secure rubber dam isolation
2. Fill syringe via hub irrigant stored in a dappen dish by the
chairside.
3. SOMMER’S TECHNIQUE
◦ Place a few drops of irrigant in the pulp chamber , then “Whirlpool”
the solution into the canal with a small file.
4. GROSSMAN’S TECHNIQUE
◦ Advocated flooding the pulp chamber with the irrigant once it was
placed into the canal. This served as a reservoir of irrigant to
replenish the one present in the root canal as it was being
instrumented.
5. When the needle is introduced into the canal & meets
resistance , it is withdrawn a few mms to prevent it from
wedging & forcing the irrigant into periapical tissues.

87. 6. Once irrigant delivery starts, look for the backflow of the
irrigant from the canal orifice.
7. The hand holding the irrigating syringe is always kept in
motion when dispensing irrigant.
8. Files potentially carry irrigant progressively deeper into
the canal by surface tension. In small canals, the files
displace the irrigant. When the instrument is withdrawn,
the irrigant usually flows into the space the file occupied.
9. Clinicians should irrigate copiously, recapitulate & re-
irrigate after each instrument size.
10. Besides using an aspirator, Grossman suggested the use
of a gauze sponge held against the tooth to absorb the
backflow of the irrigant.
11. Once the shaping & cleaning is accomplished, the irrigant
is aspirated from the canal with syringes & subsequently
dried with paper points.

88. ENDO -IRRIGATOR
◦ A system that delivers various kinds of irrigants from one in –
office air pressurized bottles at the push of a button.
◦ Various gauged canuli can be selected & attached onto the
irrigating handpiece.
◦ Allows clinicians to conveniently choose, dispense & more
effectively irrigate the root canal system.
◦

89. QUANTAC – E IRRIGATION
 Continuous Irrigation During Rotary Instrumentation
 A selfcontained fluid delivery unit that is attached to the quantec-e endo
system.
 Uses a pump console, 2 irrigation reservoirs, and tubing to provide
continuous irrigation during rotary instrumentation.
 Continuous irrigant agitation during active rotary instrumentation would
generate an increased volume of irrigant, increase irrigant contact.
 More effective canal debridement compared with syringe needle irrigation
[Setlock J et al, OOOE 2003]
 But no significant results in middle and apical third of root canal (Walter et al JOE 2002)

90. Manual Agitation Techniques
 Involves dispensing of an irrigant into a canal through
needles/cannulae of variable gauges, either passively or
with agitation by moving the needle up and down the canal
space without binding it on the canal walls.
 The design of these needles can be closed-ended, side-
vented channels.
 Good control of needle depth and the volume of irrigant
that is flushed through the canal.
 However, the closer the needle tip is positioned to the
apical tissue, the greater the chance of apical extrusion of
the irrigant.
 This must be avoided; if sodium hypochlorite were to
extrude past the apex there is a chance that a catastrophic
accident could occur.

91. Manual-Dynamic Irrigation
 Involves gently moving a well-fitting gutta-percha master
cone up and down in short 2 mm to 3 mm strokes within
an instrumented canal, thereby producing a hydrodynamic
effect and significant irrigant exchange.
 Significantly more effective than an automated-dynamic
irrigation system and static irrigation.

92. Max-i-probe
 Modified design of regular manual irrigation needles with
a well-rounded, close tip and side-port dispersal.
 Needle is available is available in a wide range of
gauges from 21 to 30 gauge.
 Luer lock connector provides a secure attachment and
easy removal from any disposable syringe.
 Rounded tip prevents the risk of perforating the apex
and allows for safe irrigation of the entire length of the
root canal.
 Dispersal of the irrigating solution through the side-port
in the cannula creates a unique upward turbulent
motion, which thoroughly irrigates the root canal
preparation but prevents solution and debris from being
expressed through the periapical foramen.

93. Rotary Brushes
 A rotary handpiece–attached microbrush has been used by
Ruddle (80) to facilitate debris and smear layer removal
from instrumented root canals. The brush includes a shaft
and a tapered brush
 section. The latter has multiple bristles extending radially
from a central
 wire core. During the debridement phase, the microbrush
rotates at
 about 300 rpm, causing the bristles to deform into the
irregularities of the preparation. This helps to displace
residual debris out of the canal in a coronal direction.
However, this product has not been commercially
 available since the patent was approved in 2001.

94. Sonic Irrigation
 operating at frequencies of 1-6 kHz
 Vibringe & Endoactivator
 Vibringe allows delivery and sonic activation of the
irrigating solution in one step. It employs a 2-piece
syringe with a rechargeable battery. The irrigant is sonically
activated, as is the needle that attaches to the syringe.
 EndoActivator System is a more recently introduced.
 It consists of a portable handpiece and three types of
disposable polymer tips of different sizes.
 tips are claimed to be strong and flexible and do not break
easily.
 Because they are smooth, they do not cut dentin.
 Effectively clean debris from lateral canals, remove the
smear layer, and dislodge.

95.  produces a cloud of debris that can be observed within a
fluid-filled pulp chamber.
 Vibrating the tip, in combination with moving the tip up
and down in short vertical strokes, synergistically produces
a powerful hydrodynamic phenomenon.
 DISADVATAGE – POLYMER TIPS ARE NOT RADIOOPAQUE

96. Sonic irrigation systems

97. ULTRASONICS
 Richman introduced ultrasound to endodontics as a means of canal
debridement in 1957.
 At the US Navy Dental Center, Martin & Cunningham developed a
system which used ultrasonics for preparing the root canal.
 The power source they employed was a magnetostrictive unit.
Recently piezoelectric units have also been used.
 This technique was termed a “SYNERGISTIC SYSTEM” because the
instrument abrades dentin & delivers a copious flow of irrigant to the
tip of the instrument
 The instrument tip is moved 0.001-0.004 of an inch through a push
pull motion of the handpiece at a frequency of 20,000-25,000 Hz
 A continuous irrigant flow is provided at 45ml/minute.

98. HEAT GENERATION:
 As the instrument is activated, frictional heat is generated
which warms the NaOCI irrigant, in turn increasing tissue
solvent properties & making it more bactericidal.
 Cameron found that a temperature peak of 450C was recorded
& that the external root surface temperature was 400C. The
thickness of the root canal dentin had an effect on the rate of
temperature change.
 They also found that because of a large difference in acoustic
density & a shallow angle of incidence much of the incident
wave was reflected & that less than half of it passed through
the irrigant- dentin interface. The wave that did not pass into
dentin was reflected, scattered or absorbed by dentin & was
converted to heat energy.

99. MECHANISMS INVOLVED
CAVITATION
 When a vibrating object is immersed in a fluid, oscillations
are set up in the liquid.
 During the rarefaction phase, the liquid can fail under
stress & form bubbles. (This is termed PSEUDOCAVITATION
by Cameron)
 During the next positive pressure phase, these vapor filed
cavities collapse implosively producing a high temperature
and pressure of the gas still contained within the cavity.
 These high temperatures & pressures in turn result in free
radical generation & radiate shock waves from the collapse
which leads to it’s WATER HAMMER ACTION on solid
surfaces.

100. ACOUSTIC STREAMING
 Definition: Rapid movement of particles of fluid in a
vortex like motion about a vibrating object but may also be
associated with small gas bubbles set into oscillation by the
fluctuating pressure field generated by the file.
 Ahmad et al found a streaming pattern where liquid was
transported from the apical end to the coronal end of the
file in a region very close to the file.
 An irregular array of rapid eddying motions was observed
concentrated at the apical end of the file. This would be
capable of dislodging debris & microorganisms.

101. Cavitation Acoustic streaming

102. TWO TYPES
 ULTRASONIC INSTRUMENTATION AND IRRIGATION (UI)
 PASSIVE ULTRASONIC IRRIGATION (PUI)
 UI -- constraint of vibratory motion and cleaning efficacy of
an ultrasonic file within the nonflared root canal space.
 UI – strip perforation & irregular flaring of root canal
 PUI irrigation allows energy to be transmitted from an
oscillating file or smooth wire to the irrigant in the root
canal by means of ultrasonic waves.
 Activation of rinsing agent without simultaneous
preparation of root canal walls
 It promotes tissue removal and dissolution

103. DISADVANTAGES:
 Very often, as the instrument comes in contact with the
wall of the root canal, it’s oscillations are damped, thereby
rendering them ineffective.

104. ULTRASONICS & MICROBRUSHES:
 Advances in small wire technology, injection moulding
processes, bristle materials & bristle attaching techniques
have led to the creation of an endodontic microbrush.
 Bristles can be attached to either
◦ Braided wires or
◦ Flexible, plastic cores
 Fabricated as either rotary or ultrasonic endobrushes
 Contain 16mm of bristles with D0 bristle diameters of 0.40,
0.50, 0.60, 0.80mm.
 Have Non standardized Gutta Percha master cone tapers:
◦ Fine
◦ Medium
◦ Large
 Used in conjunction with NaOCI & EDTA to produce clean
canals

105. ENDOVAC
 Combined irrigation/evacuation system
 Negative pressure irrigation system –
utilizes negative pressure at the apical
termination, irrigation solutions are sucked
away from the apical foramen, virtually
eliminating the risk of an irrigation accident.
 In Negative pressure irrigation, irrigant is
delivered into the access chamber, and a
very fine needle connected to a suction
device is then trasported apically and
ultimately removed via suction.

106. MICROCANNULA - STAINLESS
STEEL, SIZE 32
EVACUATION TIP
MACROCANNULA – SIZE 55,0.2 TAPER, PLASTIC

107. 1. GROSS DEBRIS EVACUATION WITH THE MASTER
DELIVERY TIP
 The Master Delivery Tip (MDT) overcomes
several clinical problems.
 Firstly, it avoids excess sodium
hypochlorite from spilling into the patient’s
mouth regardless of arch.
 Secondly, it provides frequent and abundant
flow of irrigant while maintaining the
desired effect of a constant “brim full” level
of irrigant.
 Position the MDT such that the metal
cannula within the MDT is placed just
inside the access opening of the tooth.
 Deliver irrigant via syringe and excess
fluids will be instantly evacuated
simultaneously.
 The MDT is used during coronal flaring and
after each instrument change to remove
gross debris arising from instrumentation.

108. 2) COARSE DEBRIS EVACUATION WITH THE MACRO
CANNULA
 After all instrumentation is completed,
use the MacroCannula in the Titanium
Handpiece to remove coarse debris while
using the MDT to ensure an abundant
supply of irrigant.
 In this step, the MacroCannula and the
MDT are used at the same time.
 It is helpful to have a dental assistant
deliver the irrigant with the MDT while
the clinician works the MacroCannula up
and down each canal to within a few
millimeters of the apical termination.

109. 3) MICROCANNULA MICROSCOPIC DEBRIS
EVACUATION
 Finally, using the MicroCannula
on the small Titanium
Fingerpiece, the MicroCannula
is placed to Working Length.
 The MDT delivers sufficient
irrigant as the MicroCannula
draws the solution the full
length of the root canal
evacuating microscopic debris
less than 100 microns in size.

110. RinsEndo System
 based on pressure-suction technology
 65 mL of a rinsing solution oscillating of 1.6 Hz is drawn
from an attached syringe and transported to the root
canal via an adapted cannula.
 During the suction phase, the used solution and air are
extracted from the root canal and automatically merged
with fresh rinsing solution. The pressure-suction cycles
change approximately 100 times per minute. at a
frequency.
 apical third of the canal might be effectively rinsed, with
the cannula restricted to the coronal third of the root
canal because of the pulsating nature of the fluid flow
 however, a higher risk of apical extrusion of the irrigant
was also observed

111. PhotoActivation Disinfection (PAD)
 Photodynamic Therapy (PDT)/Light Activated Therapy
(LAT) utilizes a selectively accumulated or endogenously
produced photosensitizer, activation of which by a specific
wavelength produces deleterious chemical entities that kill
bacteria.
 The strong oxidizer generated during the process can act
on multiple targets in a microbial cell, resulting in
membrane damage, enzyme activation, DNA damage etc.
 It has a wide spectrum of antimicrobial activity with a
minimal chance of giving rise to a resistant microbial
population, making it an ideal disinfectant.
 Principal agent in bacterial killing – O2 based free radical

112.  Small diode laser connected to a delivery fibre, Disposable
hand piece
 Emitter - The emitter is a flexible hollow tube coated
internally with a light diffusing material of a comparable
size to the tip of an ISO standard #40 file.
 The light is emitted over a 15 mm length of the tip with a
uniform energy density. This energy density increases over
30% at the tip.
 This is used in conjunction with a 12.7 gms/l solution of
photosensitiser, Tolonium chloride, which is a
pharmaceutical grade of the vital stain, Toluidene blue 0.

113.  Procedure
 After completion of canal preparation the canal is inoculated with
the photosensitizer solution which is left in situ for a fixed time of
60 seconds to permit the solution to come in contact with the
bacteria and diffuse through any biofilm structure. The emitter is
then placed in the root canal and irradiation carried out for 120
seconds.
 Principal
 Photosensitiser molecules attach to the membrane of the
bacteria.
 Irradiation with light at a specific wave length matched to the
peak absorption of the photosensitiser leads to the production of
singlet oxygen, which causes the bacterial cell wall to rupture
killing the bacteria.

114. ADVANTAGES
 PAD overcomes problems of antibiotic resistance.
 PAD does not pose any thermal risks due to the
low power of the PAD laser.
 PAD can be applied effectively for killing gram-
positive, gram-negative, aerobic and anaerobic
bacteria
 PAD can kill bacteria in complex biofilms, such as
subgingival plaque, which are typically resistant
to the action of antimicrobial agents.

115. CONCLUSION
 Debridement of root canal system is essential
for a predictably successful endodontic
treatment. Instrumentation of the root canal
system must be supported by an irrigation
system for best results.
 Irrigants in endodontic therapy are a must
and are many. So, it is for the clinician to
select a particular irrigant , depending on the
clinical observation, sterility, canal
configuration, and other considerations, for
the success of the root canal treatment