irrigantsinendodontics-140622152242-phpapp02

8/10/2019 irrigantsinendodontics-140622152242-phpapp02

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By

Ahmed Mostafa HusseinAssisstant lecturer

Dental Biomaterials Department

Faculty of Dentistry, Mansoura University, Egypt

2014

[email protected]


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Requirements and functions of irrigants

1. Dissolve organic and inorganic tissue.

2. Remove smear layer. (Pathway)

Disinfecting and cleaning areas inaccessible to

endodontic instruments. (pathway)

3. Flush out and remove debris prevent apicalblockage by debris. (Ingle)


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4. Antimicrobial

5. Lubricant

6. Low surface tension

7. Don't weaken the tooth structure

8. Non-toxic and non-irritant


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Advantages of smear layer removal

(Walton & Weine)

1. Allows penetration of irrigants into dentinal tubules.

2. Enhances penetration and adhesion of sealer to dentin.

3. Filling materials adapt better to the canal wall.

4. Reduces coronal and apical leakage.

N.B: The small particles of the smear layer are primarily

inorganic. (Walton)


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Functions of lubricants(Pathway)

1. Facilitate the mechanical action of endodontic

hand or rotary files

2. Increase cutting efficiency better removal of

debris

3. Reduce torque the files and reamers are less

likely to break (Weine)


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Types of irrigants

Saline, sodium hypochlorite (NaOCl),

chlorhexidine(CHX), Iodine potassium iodide (IKI),

hydrogen peroxide (H2O2), MTAD,

citric acid (CA),

EDTA (lubricant, decalcifying and chelating agent)


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* No single irrigating solution covers all of the

functions required from an irrigant.

* The alternating use of different irrigants in

the correct sequence contributes to a

successful treatment outcome.


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1. Saline (Review)

* Lacks antibacterial activity when used alone.

* Doesn't dissolve tissue.

* Has the risk of contamination if used from

containers that have been opened more than once.


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* A common concentration of NaOCl is 2.5% which

decreases toxicity and still maintains some tissue

dissolving and antimicrobial activity.


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Advantages of NaOCl(Walton)

1. Dissolve organic tissue: NaOCl is the only root-

canal irrigant that dissolves necrotic and vital

organic tissue (unique property). (Review)

2. Antimicrobial action

3. Lubricant

4. Inexpensive and readily available


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Disadvantages of NaOCl

1. Irritant to periapical tissues, mucous membrane

and skin. (Ingle)

2. Unpleasant odour.

3. Can damage clothes.

4. The use of NaOCl as the final rinse following

EDTA or citric acid (CA) produces severe erosion

of the canal-wall dentin and should be avoided.


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5. Causes haemolysis & ulceration, inhibits

neutrophil migration and damages endothelial &

fibroblast cells.

N.B: In vivo, the presence of organic matter

(inflammatory exudate and tissue remnants)

weakens NaOCl effect.


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3. Chlorhexidine (CHX)

* Relative absence of toxicity. (Ingle)

* Broad spectrum antimicrobial substantive activity

(continued antimicrobial effect), because

chlorhexidine (CHX) binds (is adsorped) and

released gradually from the hydroxyapatite

surfaces. (Review)

* 2% CHX has similar antimicrobial action as

5.25% NaOCl and is more effective againstEnterococcus faecalis. (Walton)


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* Recent reports have indicated that several

disinfecting agents such as CHX, Iodine potassium

iodide (IKI) and Ca(OH)2 are inhibited in the

presence of dentin. (Pathway)

* The activity of CHX is greatly reduced in the

presence of organic matter. (Review)

* CHX cannot be the main irrigant in standard

endodontic cases, because CHX doesn't dissolve

the smear layer or necrotic tissue. (disadvantage)


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Indications of CHX

1) 2ry endodontic infections.

2) At the end of chemomechanical preparation,

because CHX doesn't cause erosion of dentin like

NaOCl does as the final rinse after EDTA.


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4. Iodine potassium iodide (IKI)

* Iodine is less cytotoxic & irritating to vital tissues

than NaOCl & CHX, but obvious disadvantage of

iodine is a possible allergic reaction in some

patients.

* 2 & 4% Iodine potassium iodide (IKI) has

considerable antimicrobial activity, but no tissue-

dissolving property. It can be used at the end of

chemomechanical preparation like CHX.


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5. Hydrogen peroxide (H2O2) (Weine)

* H2O2 destroys anaerobic microorganisms.

* The solvent action of H2O2 is less than that of

NaOCl, so H2O2 is less damaging to periapical

tissues.


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* Many clinicians use the solutions (H2O2 &

NaOCl)

alternately during treatment. This method is

strongly suggested for irrigating canals of teeth

that have been left open for drainage, because the

effervescence is effective in dislodging foodparticles & other debris that may have packed the

canal.

* H2O2 shouldn't be the last irrigant used in acanal,

because nascent oxygen may remain and cause

pressure. Therefore NaOCl should be used to react

with H2O2 and liberate the oxygen remaining.


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6. MTAD (Walton and review)

* Mixture of tetracycline isomer (doxycycline), an

acid (citric acid) & detergent.

* Biocompatible.

* MTAD may be superior to NaOCl in antimicrobial

action.

* MTAD is effective in killing E. faecalis found in

failing treatments.


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* Although earlier studies showed promising

antibacterial effects by MTAD, recent studies have

indicated that NaOCl/EDTA combination is

equally or more effective than NaOCl/MTAD.

(Review)

* MTAD helps in removal of smear layer.* MTAD doesn't dissolve organic tissue.

(disadvantage)

* It doesn't alter physical properties of dentin.

* It could be used at the end of chemomechanical

preparation after NaOCl. (Review)


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7. Citric acid (CA)

* EDTA & citric acid (CA) effectively dissolve

inorganic material, including hydroxyapatite.

(Review)

* Help in smear layer removal. (Walton)


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8. EDTA (ethylene diamine tetraacetic acid)

* Lubricant, chelator & decalcifying agents.

* EDTA is the most effective chelating agent in

endodontic therapy.

* In general, files remove dentin faster than the

chelators can soften the canal walls. (Walton)


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* 17% EDTA for 1 min remove inorganic

components.

* EDTA is effective in smear layer removal only in

coronal & middle thirds, but not in the apical

third.

N.B: NaOCl is necessary for removal of organiccomponent.

* EDTA has little effect on periapical tissue.


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Disadvantage of EDTA

Deactivation of NaOCl by reducing the available

chlorine. (Walton)


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Contraindications of EDTA (Weine page 225)

1) A ledged or blocked canal: If a sharp instrument

is forced or rotated against a wall softened by the

chelate, a new but false canal will be started.

2) Curved canals once the larger-sized instruments

(size 30 or greater) are being used. Theseinstruments are not as flexible as the smaller sizes

and may produce root perforation.


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Indication of EDTA

The best use of chelating agents is to aid and

simplify preparation for very sclerotic canals after

the apex has already been reached with a fine

instrument.


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* Chelating agents are placed in the orifice of a

canal to be enlarged on the flutes of the enlarging

instrument or by plastic syringe.N.B: EDTA reacts with glass, so glass syringes of

that material may not be used. (Weine pages 224 & 225)


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PrecautionEDTA will remain active within the canal for 5 days

if not inactivated. If the apical constriction has beenopened, the chelate may seep out & damage the

periapical bone. For this reason, at the completion

of the appointment, the canal must be irrigated with

NaOCl to inactivate EDTA. (Weine page 226)


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Conventional irrigation by syringe

* Disposable 2.5 or 5 ml plastic syringes are useful

for endodontic irrigation. (Weine)

N.B: Larger syringes are difficult to control for

pressure, and accidents may happen. (Review)

* A commonly used needle is the 27-gauge needlewith a notched tip, allowing for solution flowback,

or the blunt-tip ProRinse. (Ingle)


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Notched tip


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Side port & rounded tip


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Selected video from youtube:

www.youtube.com/watch?v=3FVXN1sCKf8


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* All syringes for endodontic irrigation must have a

Luer-Lok design. (Review)

* The irrigating needle must be placed loosely in the

canal. To control the depth of insertion, the needle is

bent slightly at the appropriate length or a rubber

stopper is placed on the needle. (Walton)


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Luer-Lok design


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* Irrigants must be gently placed within the canals.

It is the action of intracanal instruments that

distributes the irrigant into the canal. (Weine)

* The needle is moved up and down constantly to

produce agitation & prevent binding or wedging of

the needle. (Walton)

N.B: Severe complications have been reported from

forcing irrigating solutions beyond the apex by

wedging the needle in the canal and not allowing an

adequate backflow. (Ingle)


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* The irrigant doesn't move apically more than 1

mm beyond the irrigation tip. (Walton)

* The closer the needle tip to the apex, the greater

the potential for damage to the periradicular tissues.

* The volume of irrigant is more important than the

concentration or type of irrigant. (Ingle page 502)


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* The apical 5 mm are not flushed until they have

been enlarged to size 30 and more often size 40

file. (Ingle)


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* Separate syringes should be used for each irrigant

to avoid chemical reactions between them. (Review)

*N.B: Ultrasonics proved superior effect to syringe

irrigation alone when the canal narrowed to 0.3 mm

(size 30 instrument) or less. (Ingle)

*N.B: The US Army reported the importance ofrecapitulationre-instrumentation with a smaller

instrument following each irrigation. (Ingle page 503)


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Questions

What are the irrigants that can be used for final

irrigation and why?

* CHX, IKIand MTADcan be used at the end of

chemomechanical preparation, because they doesn't

cause erosion of dentin.N.B:Some patients have allergy to iodine.

N.B:CHX has continued antimicrobial activity, why?


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* What are the irrigants that cannot be used for

final irrigation and why?

1) EDTA: why?

2) NaOCl: why?

3) H2O2: why?


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Main references1. Torabinejad M,Walton RE. Endodontics principles

and

practice. 4th ed. Saunders; 2009. p. 391-404.

2. Cohen S, Hargreaves KM. Pathways of the pulp. 9th

ed.St. Louis: Mosby; 2006. p. 318-323.

3. Ingle JI,Bakland LK. Endodontics. 5th ed. BC

Decker;2002. p. 498-505.

4. Weine FS. Endodontic therapy. 6th ed. St. Louis:

Mosby; 2004. p. 221-226

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