IRRIGANTS - In Endodontics
Seminar by
Dr. BALAMURUGAN Postgraduate Student
DEPARTMENT OF CONSERVATIVE DENTISTRY & ENDODONTICS SRI RAMACHANDRA DENTAL COLLEGE AND HOSPITAL CHENNAI 1
CONTENTS
Introduction Purpose Goals of Irrigation Factors Influencing Irrigation Root canal Irrigants Actions Chelating Agents Effects Methods of use Ultrasonics Advancements Visualization endogram Methods of Irrigation Hypo Chlorite Accident Journal References 2
INTRODUCTION
One of the most neglected phases of endodontic treatment is removal of minute fragments of organic debris, dentinal shavings and microorganisms from the root canal.
Principle of surgery is, before a wound is ready for disinfection; all necrotic material and debris must be removed. But in dentistry the need for cleaning and shaping and the importance of removing resultant debris, as well as pulp remnants are often ignored. Thorough debridement and cleaning are as necessary in endodontic treatment as in surgery.
Irrigation is the removal of minute fragments of organic debris, microorganisms and dentinal shavings from the root canal.
PURPOSE 1. Pulp chamber and root canals of non-vital teeth are filled with a gelatinous mass of necrotic pulp remnants and tissue fluid, shreds of mummified tissue and vital tissue in apical root portion. Bacteria are also present. An instrument thrust into such a canal is likely to force such noxious material through the apical foramen with a resulting periradicular inflammation and / or infection. Therefore before and at frequent intervals during instrumentation
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the canals are washed out or irrigated with a solution capable of disinfecting the canal and dissolving the organic matter. 2. Irrigation, serves the purpose of facilitating instrumentation, by lubricating canal walls and by floating out dentinal debris / fillings. 3. It may also be used to wash out food debris when the canal has been left open for drainage during acute stage of an alveolar abscess or when caries extension is upto the orifice or pulp chamber in which case food debris is trapped in the orifice or root canal.
Goals of irrigation: 1. Lavage of debris 2. Tissue dissolution 3. Antibacterial action 4. Lubrication
FACTORS INFLUENCING IRRIGATION
1. Type of remaining tissue.
Whether it is vital, necrotic or
chemically fixed tissue, irrigants are not equally effective on all three-tissue types. 2. Method of canal instrumentation, whether a step back or conventional preparation is used.
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3. Extent of instrumentation and size of last instrument used at working length (influence the penetration of irrigants). 4. Quantity and temperature of the irrigating solution. 5. The length of time of contact. 6. Presence of serum protein. 7. Depth of penetration of irrigating needle. 8. Type and gauge of irrigating needle. 9. Surface tension of irrigating solution (with alcohol / detergent). 10. Age of the solution.
ROOT CANAL IRRIGANTS
♦ Sodium hypochlorite (5.25%, 3%, 2.6%, 1%, 0.5%). ♦ NaOcl in combination with saline, water, anesthetic solutions, hydrogen peroxide (3%), glyoxide. ♦ NaOcl in combination with chelating agents. (e.g.,) EDTA, RC Prep, EDTAC. In combination with phosphoric (50%), lactic (50%) and citric (6 to 50%) acids.
Miscellaneous Irrigants
♦ 5% cheloramine T, 0.4% Iodopax, 0.1% Biosept, 0.1% Hibitane, chlorhexidine. ♦ Concentration, ideal temperature, frequency of application and delivery methods for irrigation, along with the time required for 5
these solutions to thoroughly clean a shaped root canal system is continuously being investigated.
NaOcl
♦ Introduced for treating wounds during World War I by physician Dakin. It saved many lives that may have been otherwise lost to gangrenous infection.
E.g., Clorex or purex are sources for
obtaining full strength 5.25% NaOcl. ♦ It is a powerful and inexpensive irrigant that has been shown to readily dissolve pulp tissue. ♦ Should be used clinically in concentration of 3 to 5% to take advantage of its ability to destroy all microorganisms upon direct contact and its unique ability to dissolve pulp tissue from all aspects of the root canal system. ♦ Grossman demonstrated 60 years ago, that when freshly broached pulp was put in a dappen dish filled with 5.2% NaOcl, it dissolved within 20 to 30 minutes. ♦ Studies have shown that in pre-flared canals, warming NaOcl to approximately 60°C (140°F) significantly increases the rate and effectiveness of tissue dissolution. ♦ This can be done by heating a beaker of water and then placing pre-loaded syringes of NaOcl into the warm water bath. ♦ Solution of NaOcl should be prepared fresh daily to obtain optimal clinical results. 6
♦ To maximize tissue dissolution, access cavities must be filled brimful. ♦ The potential for an irrigant is maximized when it is heated, flooded into shaped canals, and given ample time to work. ♦ Frequency of irrigation is important. As a rule a clinician should irrigate copiously, recapitulate and re-irrigate atleast after every 2 to 3 instruments.
This should be repeated more frequently in
tighter, longer and more curved canals.
Files potentially carry
irrigant progressively deeper into the canal by surface tension. However, when an instrument is placed into a relatively small canal, the file tends to displace the irrigant, but when it is withdrawn, the irrigant flows back into the space the file occupied, unless there is an air pocket.
METHODS
♦ Clinician can choose their preferred method for transporting irrigant from a variety of irrigating devices. It can be delievered in a variety of syringes and primively injected manually. ♦ Even various gauged canuli can be choosen to achieve deeper and safer placement. Certain canuli dispense irrigant through a closed ended side port delivery system. ♦ Regardless of the method of introduction, it is eventual to have a pulp chamber filled brimful with a reservoir of irrigant – to promote
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tissue dissolution, flushing out debris and 3 dimensional cleaning of the preparation. ♦ The hand that holds the irrigating syringe is always kept in motion when dispensing irrigant to prevent the needle from inadvertently wedging in the canal. Slowly injecting irrigant in combination with continuous hand movement will virtually eliminate accidents. ♦ Recently new technologies have been developed that deliver various types of online irrigants from in office air pressurized bottles. In this method clinician can select among several solutions with a push of a button.
Gauged canuli can then be selected and
attached on to the irrigating hand piece. ♦ Thus new irrigation technology allows clinicians to conveniently choose, dispense and more effectively irrigate root canal systems.
ACTIONS
NaOcl It is household bleach It is a reducing agent Clear straw-coloured Contains 5% chlorine Should be kept in cool place away from sunlight. ♦ 100% effective against bacteroides malaninogenicus ♦ Dilution and organic matter reduces its efficacy.
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♦ Disinfection is initially slow, but increases progressively ♦ Destruction of bacteria, takes place in 2 phases •
Penetration into bacterial cell wall
•
Chemical combination with protoplasm
HYDROGEN PEROXIDE
♦ It brings about foaming action in the canal through the release of nascent oxygen. ♦ Hydrogen peroxide effectively “Bubbles” out debris and mildly disinfects the canal. Oxygen liberated in an active state assists in destroying anaerobic microorganisms. ♦ But combining with NaOcl, reduces the tissue solvent properties of NaOcl.
ADVANTAGES:
♦ The effervescent reaction of H 2O2, mechanically bubbles and pushes out the debris, through the least resistant orifice into the chamber. ♦ It has mild disinfecting and bleaching action.
But H2O2, should not be the last solution used as it may react with pulp debris and blood to form gas, which when trapped with the tooth will cause continuous pain. 9
NINE-AMINO ACRIDINE
♦ An antiseptic of low toxicity. ♦ It has antimicrobial action
But it has osteogenic potential Chloramines T has also been tried as an irrigating solution. But it has little ability to dissolve necrotic tissue.
BIS-DEQUALIMIUM ACETATE (BDA)
♦ It is a disinfectant and chemotherapeutic agent ♦ Low toxicity ♦ Has lubricant action, disinfecting ability ♦ Low surface tension and low index of postoperative pain.
Improvement in post operative pain and swelling, when BDA is used is attributed to the chelation properties of BDA in removing the smear layer coated with bacteria and contaminants as well as the surfactant properties, that allowed the BDA to penetrate into areas inaccessible to instruments.
BDA is recommended as an excellent substitute for NaOcl in those patients who are allergic to the latter.
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CHELATING AGENTS
♦ EDTA → ethylene diamino tetracetic acid, was introduced into endodontic practice by Nygard and Ostby. ♦ Functions by forming a calcium –chelate solution with the calcium ion of dentin, the dentin thereby becomes friable and easier to instrument. ♦ EDTA contains 4 acetic acid groups attached to ethylenediamine.
STRUCTURAL FORMULA
C 2 H 3 O2
C 2 H 3 O2 N – CH2 – CH2 – N
C 2 H 3 O2
C 2 H 3 O2
♦ EDTA is relatively non-toxic and only slightly irritating in weak solutions. ♦ Forms highly stable, soluble, metal chelate in combination with heavy metals or alkaline earth ions. ♦ Salts of EDTA may be used to chelate the calcium ions of tooth structure and so decalcify dentin.
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FORMULA
Disodium salt of EDTA – 17.0 g Distilled water – 100.0 ml 5 N Sodium hydroxide – 9.25 ml
0.84 g of bactericide Cetavalon may be added. This 15% solution of EDTA has ph 7.3 and is called EDTAC.
Stewart and Colleagues developed a combination of EDTA and urea peroxide, which is effective lubricating and cleaning agent for root canals, and allowed deeper penetration of the medicament.
EFFECTS OF ETDA
♦ Is effective in softening dentin, as determined by a knoop indentor. ♦ Have distinct antimicrobial properties. ♦ Capable of causing a moderate degree of irritation. ♦ Has no deleterious effect when used as an irrigating solution. ♦ Removes smear layer. ♦ Extent of demineralization of dentin is directly proportional to exposure time. ♦ Effects partial demineralization of dentin to a depth of 20 to 30 µm in 5 min.
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The purpose of a chelator is for lubrication, emulsification and holding
debris
in
suspension.
Chelators
suspension or an aqueous solution.
are
either
viscous
Viscous suspensions have
several ingredients typically suspended in water-soluble vehicle. Eg., RC Prep (premier dental products) principle ingredients – EDTA ureaperoxide and propylene glycol. Glycol is the lubricant that coats instruments and facilitates their movement.
♦ Using root canal preparation in concert with NaOcl causes nascent release of oxygen that kills anaerobic bacteria. ♦ Also produces significant effervescence, creating an elevator action to evacuate debris that has dislodged from the root canal system.
METHOD OF USE:
♦ EDTA is inserted by deposing a few drops in the pulp chamber with a syringe or plastic pipette and then carefully pumping the solution into the root canal with a fine root canal instrument. ♦ When it is difficult to introduce a file, one should try to force the EDTA ahead of the instrument. ♦ If a root canal of a posterior tooth is narrow and if one risks breaking a fine instrument it is better to pump EDTA into the canal and wait 2 or 3 minutes before attempting instrumentation. Research has shown that rinsing for 1 minute with EDTA eliminates smear layer, opens up the dentinal tubules and provides a cleaner surface against which gutta-percha and sealer will adapt. 13
ULTRASONICS
♦ Ultrasonic devices have been advocated and used with the hope that they will optimally clean the root canal system, either during or after canal preparation techniques. ♦ Use of ultrasonic energy to activate irrigating solutions in optimally prepared canals continues to be intriguing. ♦ Traditionally a small file would be placed passively in the canal and ultrasonically activated. ♦ The energized file produces a fluid movement called acoustic streaming. ♦ This mechanical energy warmed the irrigating solution (NaOcl) and dislodged residual debris from the preparation. ♦ Shortcomings: the files might gauge and mar the walls of the finished preparation. ♦ Recent advancements are:
NiTi instruments, designed to activate irrigant and enhance cleaning, has been field-tested.
Advancements
in
small
wire
technology,
injection-
moulding process, bristle materials and bristle attaching techniques have enabled the creation of an endodontic microbrush.
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♦ Rotatory and ultrasonic brushes are fabricated in ISO lengths, contain 16mm of bristles with Do diameter of 0.40, 0.50, 0.60, 0.80mm. ♦ Activated at 300 RPM. ♦ Helical bristle pattern effectively augers residual debris out of the canal in a coronal direction. ♦ These, brush the walls of the preparation and activate solution of NaOcl and 17% EDTA to produce cleaner canals.
ADVANCEMENTS IN IRRIGATING SOLUTIONS
“Visualization” Endogram NaOcl and chelating agents are radiolucent.
Therefore these
reagents do not help the dentist radiographically to visualize the anatomy of root canal system.
Recently a new experimental irrigating solution, the Ruddle solution has been formulated to provide a break through in clinical endodontics.
It contains •
5% NaOcl
•
17% EDTA
•
Hypaque
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♦ Hypaque is a high contrast dye used in medicine for angiography, artriography etc. ♦ It is an aqueous solution of two iodine salts •
Diatrizoate meglumine
•
Sodium iodine
♦ Specific gravity similar to NaOcl and is water soluble ♦ pH 6.7 to 7.7 and it is stable in room temperature ♦ This composition provides the solvent action of full strength NaOcl visualization (radio density III to gutta-percha) and improved penetration (tensio active agent which lowers surface tension). ♦ Clinicians can use an endogram to visualize the microanatomy, verify the shape and monitor the remaining root wall thickness during preparation procedures. ♦ Useful in visualizing pathologic events such as caries, fractures, missed canals and leaking restorations also internal resorption.
METHOD OF USE AND TECHNIQUE
♦ Technique is simple, fast and effective. Plastic disposable syringes are adequate. ♦ Needle - Several types
Bent to allow easier delivery of irrigating solution
Commonly used is 27 gauge with a notched tip, allowing the solution to flow back. 16
♦ Needle should be passively inserted into the canal and should not engage the walls. Sufficient room between needle and canal wall allows for the return flow of the solution and avoids forcing of solution into the periapical tissue. ♦ When one is certain that the needle does not bind, the solution should be ejected from the syringe with little or no pressure on the plunger. ♦ The object is to wash out the canal and not to force the solution under pressure into the periradicular tissue. ♦ Proximity of needle tip to the apex plays an important role in removing root canal debris. ♦ In narrow root canals, the tip of needle is placed near the root canal orifice and the irrigant is discharged until it fills the pulp chamber. The solution is then pumped into each root canal with a root canal file. ♦ A perforated irrigating needle has been developed to deliver irrigant 360° in the root canal. Disadvantage is that it is delicate and bends out of shape ♦ Max – I probe is a needle with a closed tip and side delivery system. It is the safest needle. Researchers found that Max-I probe cleaned the canal to the apex. Advantage is that it has closed end, eliminates possibilities of puncture of apical foramen or “water cannon” effect from open-end needle.
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♌ The return flow of solution is caught in a gauze or is aspirated. Finally root canal debris removal is dependent on canal diameter, viscosity of solution, diameter and depth of penetration of irrigating needle and volume of solution used.
HYPO CHLORITE ACCIDENT
Accident injection of sodium hypochlorite into the periapical tissues is an experience that neither the patient nor practioners will soon forget.
Immediately after NaOcl has been expressed beyond the apex the patient might have
1. Severe pain, even in areas that were previously anesthetized. 2. Swelling 3. Profuse bleeding both interstitially and through the tooth
CAUSES
1. Forceful injection of irrigating solution 2. Having an irrigating needle wedged into a root canal 3. Irrigating a tooth with large apical foramen, apical resorption, or an immature apex.
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4. Patients
may
have
increasing
edema
and
ecchymosis,
accompanied by tissue necrosis, paresthesia and secondary infection. 5. Patients recover in 1 to 2 weeks. 6. Volume, concentration, temperature of NaOcl with operators timely response will decide the outcome.
MANAGEMENT
1. Recognition by clinician. 2. Pain and swelling can be attended by giving a regional block with a long acting anesthetic. 3. Clinician must assure and calm the patient. N 2O sedation will help. 4. Tooth monitored for 30 minutes.
If black discharge occurs
showed be evaluated or tooth left open for 24 hours. 5. Antibiotic coverage (Penicillin 500mg, 5 times / daily for 7 days). 6. Analgesic (acetaminophen –narcotic analgesic). 7. Corticosteriods, as they minimize inflammatory process. 8. First 6 hours cold compression followed with warm compress thereafter.
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PREVENTION
1.
Irrigating needle should be bent at center to confine tip to higher levels in the root canal.
2.
Needle should not bind.
3.
Needle should be oscillated in and out while depositing.
4.
Irrigant should be expressed slowly and gently.
5.
Hub of the needle should be checked to prevent in advertant seperation.
JOURNALS
♦
R. White et al “Residual antimicrobial activity after canal irrigation with chlorhexidine”. J.O.E. April 1997, 23(4), 229-31. “The objective of endodontic therapy is to disinfect the root canal system before obturation of the canal. Sodium hypochlorite is the irrigant of choice, but it has been reported that a 2.0% of chlorhexidine gluconate can be used as an irrigant.
It is less
malodorous and toxic and possessed invitro antimicrobial activity equivalent to that of NaOcl. In addition to its immediate killing, it has
been
reported
that
it
antimicrobial activity”.
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possess
substantive
residual
♦
Michael J. Jeansonne et al “A comparison of 2.0% chlorhexidine gluconate and 5.25% sodium hypochlorite as antimicrobial endodontic irrigants”.
J.O.E.
June 1994, 20(5), 276-278.
“Chlorhexidine gluconate has become recognized as an effective oral
antimicrobial
agent.
It
is
a
broad
spectrum,
has
substantivity extended residual activity, relative absence of toxicity.
The number of post irrigant positive cultures and the
CFU in positive cultures obtained from chlorhexidine treated teeth were lower than the number obtained from NaOcl treated teeth”.
♦
Ohara et al “Antibacterial effects of various endodontic irrigants on selected anaerobic bacteria” J. O. Endodontics and Dental Traumatology, 1993. 9, 95-100. “Antibacterial effectiveness of NaOcl → is by the formation of hypochlorous
acid
when
in
contact
with
organic
debris.
Hypochlorus acid exerts its effect by the oxidation of sulfhydryl groups of bacterial enzyme systems thereby disrupting the metabolism of the microorganism NaOcl showed good antibacterial activity at a dilution of 1/10.
But it was secondary to
chlorhexidine.
♦ Fugen Tasmen et al “Surface Tension of root canal irrigants” J. O. E. Oct 2000, (26(10), 586-587. “Wettability of a solution depends on its surface tension, which can be defined as the force between molecules that produces a 21
tendency for the surface area of a liquid to decrease. This force tends to inhibit the spread of a liquid over a surface or to limit its ability to penetrate a capillary tube.
So reducing the surface
tension can increase the efficacy of an irrigant, because wettability is of prime importance. By the important of wettability it is also possible that an irrigant could extend its protein solvent capability on perform the bactericidal function through penetration into uninstrumented areas of the root canal system.
o Poly sorbate 80 reduced surface tension of distilled water, alcohol, NaOcl and EDTA by 15 to 20%. o Among the irrigants tested, cetredixine (0.2% chlorhexidine gluconate + surface anti-irrigant 0.2% cetrimide) showed lowest surface tension.
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