RECENT ADVANCEMENT IN IRRIGATING SOLUTIONS AND IRRIGATING DEVICES

INTRODUCTIONThe pulp chamber and root canals of untreated nonvital teeth are filled with a gelatinous mass of necrotic pulp remnants and tissue fluid. Essential to endodontic success is the careful removal of these remnants, microbes, and dentinal filings from the root canal system.

Forcing this noxious infected material through the apical foramen might lead to an acute apical abscess.

The apical portion of the root canal is especially important because of its relationship to the periradicular tissue

Although instrumentation of the root canal is the primary method of canal dbridement, irrigation is a critical adjunct.

Irregularities in canal systems such as narrow isthmi and apical deltas prevent complete dbridement by mechanical instrumentation alone.

HISTORYPrior to 1940s Water was the most commonly used irrigant as it was:Readily available.Inexpensive.Provided a lubricating effect during instrumentation.

During 1940s proteolytic enzymes like streptokinase, streptodomase, papain, enzyme etc. were used They had tissue dissolving property.In 1943, Grossman introduced the concept of using oxidizing agents as irrigants. He recommended that solution of 3% hydrogen peroxide be alternated with a solution of 5.25% sodium hypochlorite.so that effervescence action results in removal of debris from the canal system.

Recently another oxidizing agent, glyoxide has been recommended, particularly for narrow, curved canals. Contains carbamide peroxide in an anhydrous glycerol base which is highly viscous, provides good lubrication, has little antibacterial activity & not a tissue solvent.In 1945, Daniel formulated an irrigating solution comprising of a aminoacridine.In 1970s chelating agents were used increasingly because of their biologically acceptable properties.

IMPORTANCE OF IRRIGATIONIrrigation serves as a Physical flush to remove debris As well as serving as a bactericidal agent, Tissue solvent, and Lubricant. Furthermore, some irrigants are effective in eliminating the smear layer.

Goals of irrigation;According to INGLE-1.Lavage of debris.2.Tissue dissolution.3.Antibacterial action.4.Lubrication.

Ideal requirements of irrigating solutions (DCNA; 1.Antimicrobial property.2.Dissolve necrotic tissue debris.3.Aid in debridement of the root canal system.4.Non-toxic to the periapical tissues

Role of intracanal irrigants (Weine):Irrigants perform important physical and biologic function during endodontic therapy1.Loosens tissue debris Dentinal shavings and microorganisms from the irregular radicular dentine walls.2.Flushes The above into the pulp chamber space where it is easily removed by aspiration or paper points.

3.Dissolves Organic tissues that are entrapped in accessory or lateral canals and that is inaccessible to hand instruments.4.Antibacterial action Certain irrigants posses germicidal action, other reduce the number of microorganisms by eliminating the source or substrate for survival of these organisms.5.Lubricating effect : Facilitates instrumentation of the canals.6.Irrigants possess a bleaching action

REMOVAL OF SMEAR LAYERDuring root canal preparation, cut debris is smeared over the dentinal surface, forming a smear layer.

The smear layer has been defined as any debris composed of organic and inorganic particles of calcified tissue, necrotic tissue, and microorganisms.

It has been described by scanning electron microscopy (SEM)as an amorphous substance with an irregular surface.

SEM studies have demonstrated that the smear layer covers the anatomical structures of the root canal. The smear layer thickness is not constant but ranges from 1 to 5 m.There are two layers ,The surface layer,i.e.,smear debris (SD), covers the orifices of dentinal tubules and is 2 to 5 m thick.The inner layer penetrates into dentinal tubules, occludes them and provides a natural barrier against fluid movement within the tubules.

The smear layer thickness can be influenced by the type of a root instrument used and by the amount and composition of irrigants employed.It has become apparent that only agents combining both organic and inorganic solvents can effectively and totally remove smear layers.However, not only the combinations of agents but also the way of application and their quantity have been found to be important .

The syringe application of irrigants, which is used most frequently, can be replaced by treatment of the root canal by ultrasound.In endodontics,the ultrasound technique utilizes the mechanical and cavitation effect and acoustic streaming of ultrasound to remove the surface component of the smear layer.

CLASSIFICATION OF IRRIGATING SOLUTIONS I.ACIDSORGANICCitric acidMaleic acidTannic acidPhosphoric acidTublicidLactic acid

INORGANICH2SO4 50%HCl 30%

CHELATING AGENTSEDTAEDTACRC-Prep

II.PROTEOLYTIC ENZYMES-Streptokinase.-Enzymol.-Streptodornase.-Purified trypsin.-Papain

III.OXIDIZING AGENTS-3% hydrogen peroxide.-Urea peroxide.-Glyoxide. IV.ALKALINE SOLUTIONSSodium dioxide.Urea.

Sodium hydroxide.Sodium hypochlorite 0.5%, 1%, 2.6%, 5.25%.Potassium hydroxide.Chloramine-T.

V. OTHERSChlorhexidine gluconate 0.2%Glutaraldehyde.Oxidative potential water.2% potentiated acid.Calcium hydroxide solution.

COMMONLY USED IRRIGATING SOLUTIONSSODIUM HYPOCHLORITEMost popular irrigating solutions. Used as an irrigant for over 4 decades.It was first recommended by HENRY DAKIN in 1915 and was called as DAKINs SOLUTION. During the time of World War-II (NaOCl buffered with sodium bicarbonate) it was used for the treatment of infected wounds.

Manufactured: It is made by bubbling chlorine gas through NaOH to form equal amounts of sodium hypochlorite and sodium chloride. (NaOH gas NaOCl + NaCl2)

NaOCl has been used in various concentrations ranging from 0.5-5.25%.

Most commonly used concentration 2.5%

Antibacterial: Direct contact with microorganisms. Vapor action.Destruction of the bacteria takes place in two phases:1. Penetration into the bacterial cell.2. Chemical combination with the protoplasm of the bacterial cell that destroys it.

Sodium hypochlorite is a strong base (pH>11). At 1% concentration,sodium hypochlorite presents ;A surface tension equal to 75 dynes/cm,65.5 ms of conductivity, 1.04 g/cm 3 of density and Moistening capacity equal to 1 h and 27 min. The antimicrobial effectiveness of sodium hypochlorite, based in its high pH (hydroxyl ions action), is similar to the mechanism of action of calcium hydroxide

The high pH of sodium hypochlorite interferes in the cytoplasmic membrane integrity with an:- Irreversible enzymatic inhibition, Biosynthetic alterations in cellular metabolism and Phospholipid degradation observed in lipidic peroxidation.

TISSUE SOLVENT PROPERTYNaOCl possesses strong tissue dissolution property .This equals to that of H2SO4 and HCl.The solvent action of NaOCl has been attributed to its high alkalinity.Grossman and Meiman reported that 5% sodium hypochlorite dissolves pulp tissue in 20 min to 2 h.

5.25% of NaOCl is capable of penetrating into the dentinal tubules & dissolving the contents of tubules adjacent to the main canal.

This is an extremely important property for an endodontic irrigant because of the irregularities in the surface of the canal walls which prevents contact by instruments.

Other Properties of NaOCl 1. Lubricant for effective instrumentation.2. Bleaching action on discolored teeth.3. Increased permeability of dentinal tubules for easier penetration of an intra-canal medicaments.

Sodium Hypochlorite Used in Combination withOther Medicaments;Whether sodium hypochlorite should be used alone or in combination with other agents is also a source of controversy. There is increasing evidence that the efficacy of sodium hypochlorite,as an antibacterial agent, is increased when it is used in combination with other solutions, such as calciumhydroxide, EDTAC, or chlorhexidine. Hasselgren et al.found that pretreatment of tissue with calcium hydroxide can enhance the tissue-dissolving effect of sodium hypochlorite.

Wadachi et al found that the combination of calcium hydroxide and sodium hypochlorite was more effective than using either medicament alone.

Other variables to be considered include temperature as well as shelf life of the solution.

The antimicrobial property may be achieved in a significantly lesser time by pre-warming the solution (room temperature 22C-body temperature 37C).

NaOCl and Smear layersNaOCl alone is not very effective in removal of the smear layer, but when used in conjunction with other solutions or with ultrasonics it has shown to remove the smear layer effectively.Yamada and associates (1983) reported that a final flushing of 17% EDTA, followed by 10ml of 5.25% NaOCl, was more effective in removing both inorganic and organic debris. These authors concluded, that flushing with a chelating agent removed the final calcific sludge that remained on the canal walls.

Flushing with 10ml NaOCl removed any remaining organic tissue, thus leaving patent dentinal tubules on the surface of the canal walls.

NaOCl has been to deplete dentin of organic compounds & increase the permeability

HYDROGEN PEROXIDE

For years 3% H2O2 was recommended as a canal irrigant because Its effervescent action in presence of blood products.Disinfecting properties.

Actions:1)Effervesent action:This action was specially indicated in mandibular teeth where the bubbling of the peroxide was thought to lift debris from the canal system almost defying gravity.However, H2O2 does not possess tissue dissolution properties and is not effective as a lubricant.Hence, alternate use of H2O2 + NaOCl irrigating solutions was recommended by Grossman

This alternate irrigation regimen during chemicomechanical preparation produces.1.Transient but energetic effervescence that mechanically forces out debris and microorganisms out of the canal.2.At the same time the O2 that is liberated in an active state assists in destroying anaerobic microorganisms.

3.In combination with NaOCl effectively removes the soft tissue debris.4.The permeability of dentinal tubules is increased allowing deeper penetration of intracanal medicament.5.Increases the bleaching action on discolored teeth.

CHELATING AGENTS

Chelating agents were introduced by Nygaard-Ostby in1957,as an aid for preparation narrow and calcified root canals .A liquid solution of ethylenediaminetetraacetic acid (EDTA) was thought to chemically soften dentin.CHELATOR PREPARATIONS:Liquid chelators:Calcinase: Contains 17% Sodium acetate, sodium hydroxide as a stabilizer and purified water.

REDTA ( Roth International ) has 17% EDTA solution with addition of 0.84g Cetyl-tri-methyl-ammonium bromide ( Cetrimide )to reduce the surface tension with 9.25 ml 5 M sodium hydroxide and 100ml distill water.

EDTA-T: Contains 17% EDTA+Sodium lauryl ether sulfate (Tergentol) as a detergent.

EGTA: (Sigma) is a chelator whose main component is ethylene glycol bis ( b-amino-ethyl-ether) N,N,N,N-tetra acetic acid. It is reported to bind Ca+ more specifically than EDTA

Largal ultra (septodent) contains 15% EDTA, 0.75% Cetyl-tri-methyl-ammonium bromide ( Certimide ) & sodium hydroxide to adjust the pH value to 7.4SALVIZOL (Ravens,Germany) is based on 5% amino-quinal-di-numdiacetate in propylene glycol with pH 6.6 Calcinase slide : it contains 15% sodium EDTA &58 to 60% water. Has alkaline pH value of 8-9.ADVANTAGESwater soluble hence easily rinsed from root canal system . The gel is firm at room temperature and develops a creamy consistency when agitated .

RC-Prep : It contains 15% EDTA, 10% Urea peroxide and glycol in aqueous ointment base .Oxygen is set free by reaction of NaOCl with RC-Prep resulting in effervescence, so that pulpal remnants and blood coagulates can be easily removed from the root canal wall (Stewart et al). Urea peroxide retains its antimicrobial action in presence of blood .The manufacturers claim that tooth can be bleached in this wayGlycol acts as a lubricant, it also inhibits the oxidation of EDTA by urea peroxide.

GLYDE FILE :

Is composed of 15% EDTA & 10% Urea peroxide in aqueous solution. It has got properties similar to RC-Prep

FILECARE EDTA & FILE EZE are the other EDTA available in the market .

Clinical recommendation;1)Root canal preparation can be carried out with the aid of chelator paste.This may be introduced into the root canal with the preparation instrument. The canals first should have been flooded with NaOCl to dissolve vital or necrotic tissue.2)A chelator in paste form serves as a lubricant for files and may reduce the risk of instrument fracture in the canal.3) Preferably NaOCl solution should be used during preparation because of its antibacterial and tissue dissolving property

4) A final intensive rinse with 17% EDTA reduces the extent of the smear layer remaining which in turn results in a cleaner canal wall and better adaptation of the root fillings to the canal walls.5) EDTA containing agents should be used between 1-5 minutes .6) Liquid EDTA solution may be introduced into the pulp chamber to identify the entrance of calcified canals.7) The differences in certain properties and modes of action of individual chelators found in the few comparative studies do not allow the recommendation of any particular chelator preparation,

8)EDTA pretreatment may reduce bond strength of adhesive materials and obturative materials9) There is no evidence for bleaching effect when using EDTA preparations containing urea peroxide.10) Apical extrusion of the chelator solution should be avoided.

ADVANCEMENT IN IRRIGATING SOLUTIONS

Chlorhexidine gluconate

It is a cationic chlorophenyl bisguanide with bacteriostatic and bacteriocidal action. The cation of the chlorhexidine as antiplaque agent was suggested by schroeder in 1969. The most common preparation is with digluconate salt ,because of higher water solubility.

Antibacterial actionAt physiologic pH CHX is a large dicationic molecule, with the positive charge distributed over the nitrogen atoms on either side of the heamatoxylin bridge. The bacterial cell is characteristically negatively charged. The cationic chlorhexidine molecule is rapidly attracted to the negatively charged bacterial cell surface with specific and strong adsorption to phosphate containing compounds. This alters the integrity of the bacterial cell membrane and CHX is attracted towards the inner cell membrane.

CHX binds to the phospholipids in the inner membrane and cause leakage of low molecular weight components such as potassium ions.At this sub lethal stage the effects of CHX are reversible. Removal of excess of CHX by neutralizers allow the bacterial cell to recover

Increasing the conc. Of CHX cause progressively greater damage to the membrane, this is reflected in the size of permeable species lost from the cell.As the conc.of CHX increases, leakage of low molecular cytoplasmic components fall reflecting the coagulation and precipitation of the cytoplasm by the formation of phosphated complexes such as ATP and nucleic acid. This stage is irreversible.

Properties of CHX;It possesses a broad-spectrum antimicrobial action, substantivity, and a relative absence of toxicity.However, chlorhexidine gluconate is not known to possess a tissue-dissolving property.The results from the individual trial of chlorhexidine gluconate and sodium hypochlorite indicate that they are equally effective antibacterial agents.

However, when Kuruvilla and Kamath combined the solutions within the root canal, the results showed that the alternate use of sodium hypochlorite and chlorhexidine gluconate irrigants resulted in a greater reduction of microbial flora (84.6%) when compared with the individual use of sodium hypochlorite (59.4%) or chlorhexidine gluconate (70%) alone.White et al. found that chlorhexidine instills effective antimicrobial activity for many hours after instrumentation.

Although sodium hypochlorite is equally effective on initial exposure, it is not a substantive antimicrobial agent.

Dametto et al found that on initial exposure to chlorhexidine, antimicrobial activity is at least as effective as with NaOCl. Its substantive antimicrobial activity offers potential protection of the canal tissues for as many as 7 days after instrumentation.

Microbial activity of 2% chlorhexidine, gel and liquid, are more effective than 5.25% NaOCl in keeping a low Enterococcus faecalis CFU count 7 days after bio-mechanical instrumentation. It was concluded that chlorhexidine gluconate, in gel and liquid forms, has potential for use as an auxiliary antimicrobial agent during the biomechanical procedures.Chlorhexidine substantivity in root canal dentin was also studied by Sidney et al. The results of this study indicated that CHX is retained in root canal dentin in antimicrobially effective amounts for up to 12 weeks.

An Effective Method of Inactivating Chlorhexidine;An effective inactivating agent is required for chlorhexidine that would facilitate removal of all residual antimicrobial effect, which may cause false negative results during microbiologic culturing.The combination of 3% Tween 80 and 0.3% L-a- lecithin was found to be the most effective inactivating agent, allowing full recovery of the test organisms in the presence of chlorhexidine

OXIDATIVE POTENTIAL WATEROPW has been used extensively in Japan for household and agricultural disinfection because of its safety and bactericidal effectiveness.

According to the manufacturers claims, the antimicrobial and antiviral activities of OPW are sufficiently powerful to kill a wide variety of pathogens, including Methicillin resistant Staphylococcus Aureus (MRSA) and HIV.

The scientific basis for the development of the OPW is that microorganisms cannot survive in an aqueous environment with both low pH (less than 3) and high oxidation-reduction potential (greater than 0.9 V) (Becking et al. 1960).

OPW has strong anti-microbial activity, killing viruses as well as bacteria, an unusually low pH of 2.7 or less, and oxidation-reduction potentials of 1050 mV or greater (Okuda et al. 1994).

This is considerably greater than tap water, which, in Japan, averages 300 mV to 400 mV, and greater than several activated oxygen-containing antimicrobial constituents, such as HOCl and O 3 .

It has been confirmed that OPW can condition both enamel and dentine for bonding with composite resin because of its low pH (Inoue et al. 1994).

Oxidative potential water is well suited for dental treatment because of its low toxicity and lack of irritation to soft tissues,

It quickly loses its high oxidation-reduction potential and low pH when it reacts with light-sensitive and/or organic substances.

For these reasons it is completely safe as a root canal irrigant. A previous study (Hata et al. 1996) showed that OPW effectively removed the smear layer from instrumented canal walls when used as an irrigant

NISINNisin is a naturally occurring antimicrobial peptide Produced by strains of Lactococcus lactis, nisin is an antibiotic peptide, and is a class I bacteriocin (Klaenhammer 1993). Nisin is safe to humans and is used extensively as a food preservative in over 40 countries (Delves-Broughton 1990), mainly in preservation of meat and dairy products

The mode of action of nisin, while not completely under-stood, is due to interaction with the phospholipid membrane of the target bacterial cell (Driessen et al. 1995).

Nisin disrupts the cellular membrane inducing leakage of small intracellular contents from the cell (Montville & Chen 1998).

Nisin is comparable with calcium hydroxide in its ability to eliminate the species tested, both within the root canal and associated canal wall radicular dentine in vitro. The ability of nisin to effectively kill E. faecalis -- to which E. faecalis has no defense mechanism. Nisin is reported to be active against a broad range of Gram-positive bacteria (Kuipers et al. 1992).

ELECTRO-CHEMICALLY ACTIVATING WATER

Over the course of the past 28 years Russian scientists have developed and refined the process of electro-chemically activating water. (Leonov 1997, Bakhir 1997).

ECA is produced from water and saline solution by a special unit that houses a unique flow-through electrolytic module (FEM).

The FEM contains the anode, made from titanium and coated with rutheniumoxide, iridium and platinum, and the cathode, made from titanium coated with pyrocarbon and glass-carbon.

The physical and chemical nature of ECA is not yet fully understood. Two types of ECA solution are produced.

Anolyte has a high oxidation potential (plus 400 to plus 1200 millivolts). The manufacturers claim that it is possible to produce acidic, neutral or alkaline anolyte (pH 29), and that anolyte is antimicrobial

Catholyte is an alkaline solution (pH 712) with a high reduction potential (minus 80 to minus 900 millivolts). Catholyte is reputed to have a strong cleaning or detergent effect.

Both these solutions remain in the metastable state for approximately 48 h before the solution returns to the stable state, becoming inactive once more.

BIS-DEQUALINIUM ACETATE (BDA)

Kaufman reported the success of several cases using BDA as a disinfectant and chemotherapeutic agent He cited its low toxicity, lubrication action, disinfecting ability, and low surface tension, as well as its chelating properties and low incidence of post-treatment pain

Others have pointed out the efficacy of BDA. In one report, it was rated superior to sodium hypochlorite in dbriding the apical third.

Marketed as Solvidont (Dentsply/DeTrey, Switzerland), the University of Malaysia reported a remarkable decrease in postoperative pain and swelling when BDA was used.

They attributed these results to the chelation properties of BDA in removing the smear layer coated with bacteria and contaminants as well as the surfactant properties that allow BDA to penetrate into areas inaccessible to instruments. Bis-dequalinium acetate is recommended as an excellent substitute for sodium hypochlorite in those patients who are allergic to the latter.

Metranidazole

Antibiotic spectrum confined solely to obligate anaerobes.Active against bacteroides, porphyromonas fusibacterium, clostridium and peptococci and peptostreptococci.Comes as an injection: Metranidazole 500mg, NaCl2 0.8, Water.

Barnett and Tronstad reported the successful use of metranidazole in controlling infections by bacterioides spp and pseudomonas spp colonized at root ends of endodontically treated teeth that had failed to heal and remained refractory to all other treatment.

DOXYCYCLINE HYDROCHLORIDEMore recently DH, a hydroxy derivative of tetracycline is under study as an irrigant. It is the most potent anticollagenase antibiotic among commercially available tetracyclines.The tetracyclines are broad spectrum antibiotics demonstrated to be effective in control of periodontal pathogens.

Advantages:1. The dentin surface is capable of acting as a reservoir by adsorbing and slowly releasing antibacterial levels of doxycycline into the adjacent environment for several days following topical applications of this antibiotic solutions.2. Inhibit extracellular collagenase activity and bone resorption.

Ruddle solution

This contains 5% NaOCl, hypaque, and 17% EDTA.Hypaque is an aqueous solution of 2 iodine salts diatrizoate meglumine and sodium iodine. It is water soluble with pH of 6.7-7.7.

This composition simultaneously provides the solvent action of full-strength NaOCl, Visualization ( radiodensity), Penetration ( tensioactive agent )

MTAD

It is a mixture of a tetracycline isomer (doxycycline), an acid [citric acid)], and a detergent (Tween 80 )

Tetracycline is bacteriostatic in nature. This property may be advantageous because in the absence of bacterial cell lysis, antigenic by-products (i.e. endotoxin) are not released.

Tetracycline has many unique properties other than its antimicrobial effect. It has a low pH and thus can act as a calcium chelator and cause enamel and root surface demineralization . Its surface demineralization of dentin is comparable to that seen using citric acid .

In addition, it has been shown that it is a substantive medication (becomes absorbed and gradually released from tooth structures such as dentin and cementum

Finally, studies have shown that tetracycline significantly enhances healing after surgical periodontal therapy.

Studies have shown that MTAD as a final rinse is capable of removing the smear layer with minimal erosive changes on the surface of dentin. Experimentation with various concentrations of these materials showed that a mixture of doxycycline, citric acid, and Tween-80 was capable of removing the smear layer from the surface of instrumented root canals better than a combination of only doxycycline and citric acid.

In another study, Beltz et al. investigated the amount of tissue loss after exposing bovine pulp and dentin to various concentrations of NaOCl, EDTA, or MTAD. Their results showed that various concentrations of NaOCl removed organic components of pulp and dentin effectively.

The soluble effects of EDTA on pulp and dentin were somewhat similar to those of MTAD. The major difference between the actions of these solutions is a high binding affinity of doxycycline present in MTAD for the dentin.It is also found that MTAD maintains its bactericidal properties significantly more than NaOCl or EDTA.

Cytotoxicity is less when compared to sodium hypochlorite. There was no effect on flexural strength and modulus of elasticity of dentin when MTAD was used

OZONEOzone is a pale blue gas which is made up of three atoms of oxygen with a cyclic structure

The medical generator of ozone produces it from pure oxygen passing through a high voltage gradient of 5-13 Mega volts according to the reaction, 3O2 + 68,400cal--------2O3

Ozone is 1.6 fold denser and 10 fold more soluble in water than oxygen.It is the third most potent oxidant after fluorine and persulphate.It is an unstable gas that cannot be stored and should be used at once.It has a half life of 40 mins. But when mixed into pyrogen free water , the half life is 9-10 hrs at ph-7 and at 20 C

OZONE THERAPY IN ENDODONTICS; It is difficult to achieve the objective of complete sterilization of the root canal system by means of conventional Endodontics

Being able to sterilize the root canal system completely would significantly improve the prognosis for all teeth to be treated Endodontically.

The application of ozone makes the complete sterilization of the root canal system a real possibility in the near future. Tooth that is to be treated Endodontically needs to be built up so that the clinical crown is restored. The Ozone is applied from the access opening , making the technical realization quite a simple process.

There are five differently sized silicone cups available to enable perfect tooth sealing

Inserting the ozone cannula into the prepared root canal

Endodontic treatment using ozone with complete seal

The ability of Ozone as a root canal disinfectant depends upon; The ability of ozone to penetrate the root canal system to the apex

The effect of any proceeding preparation for certain instrument sizes.To ensure the exact canal size for the placement of cannula and proper application of ozone towards apex ,further develepments in the ozone equipment are in progress.

Waterlase Laser

For years, lasers have been used in dentistry to improve the comfort, precision, efficiency and effectiveness of many procedures. Waterlase uses the Hydrokinetic process which gently washes away decay with YSGG laser-energized water droplets. Hydrokinetic energy is produced by combining a spray of atomized water with laser energy.

The resulting Waterlase (Hydrokinetic) energy gently and precisely removes a wide range of human tissue including tooth enamel (the hardest substance in the body), and soft tissue (gum tissue) with no heat or discomfort in most cases.

What can the Waterlase be used for?Root Canals Decay Removal Cavity Preparation Smile Design General soft tissue procedures

Benefits of Waterlase Endodontics:Superior intra-operative and post-operative patient comfort. Reduced post-operative complications such as inflammation, swelling and pain. Versatile and effective for root canal preparation. No vibration and pressure as found with conventional instruments. Little or no anesthesia. More healthy tooth structure is preserved.

IRRIGATING DEVICES

Although the technique for irrigation is simple, the potential for serious complications exists. Regardless of the delivery system, the solution must be introduced slowly and the needle never wedged in the canal.The greatest danger exists from forcing the irrigant and canal debris into the periradicular tissue owing to a piston-like effect. Several types of plastic disposable syringes are available. Usually, the irrigating solution is kept in a dappen dish that is kept filled. The syringe is filled by immersing the hub into the solution while withdrawing the plunger.

ProRinse.

In case of prorinse system the needle, or probe is attached. Care must be taken with irrigants like sodium hypochlorite to prevent accidents. The irrigating needle may be one of several types. It should be bent to allow easier delivery of the solution and to prevent deep penetration of the needle or probe.

A commonly used needle is the 27-gauge needle with a notched tip, allowing for solution flowback or the blunt-end ProRinse.

Monoject endodontic needlesMoser and Heuer reported Monoject endodontic needles to be the most efficient delivery system in which longer needles of a blunted,open-end system were inserted to the full length of the canal.

Stropko Ni-Ti Irrigation NeedlesStropko Ni-Ti Irrigation Needles available from Vista Dental. They are available in short (17 mm) and (25 mm) long sizes and can be sterilized and reused. Needle size is 27 guage, side vented ,flexibility and their resistance to clogging helps in effective irrigation.

Closed-end needle eliminates possibilities of puncture of the apical foramen or a water cannon effect from open-end needles. [Courtesy of Dentsply/Tulsa Dental.]

Endo Irrigator IIThe Endo Irrigator II has 3 reservoirs. The gun on the right has four buttons. Three activate the solutions and one is for suction. The device has a built in heater.

Walton and Torabinejad stated that Perhaps the most important factor is the delivery system and not the irrigating solution per se.

Furthermore, it was found that the volume of the irrigant is more important than the concentration or type of irrigant.

Wedging a needle in a canal is dangerous and can cause serious sequelae.

Canal size and shape are crucial to the penetration of the irrigant. The apical 5 mm are not flushed until they have been enlarged to size 30 and more often size 40 file.It is reported that In order to be effective, the needle delivering the solution must come in close proximity to the material to be removed.Small-diameter needles were found to be more effective in reaching adequate depth but were more prone to problems of possible breakage and difficulty in expressing the irrigant from the narrow needles.

Kahn, Rosenberg et al. at New York University, in an in vitro study, tested various methods of irrigating the canal. ProRinse probes were highly effective in all gauges and in all sizes of canals tested. The Micromega 1500 and CaviEndo systems were highly effective at the size 20, 25, and 30 K-file levels.The effectiveness of the ProRinse seemed related to its design. It has a blunt tip, with the lumen 2 mm from the tip. Expression of fluid through the lumen creates turbulence around and beyond the end of the probe.

The effectiveness of the ProRinse seemed related to its design. It has a blunt tip, with the lumen 2 mm from the tip. Expression of fluid through the lumen creates turbulence around and beyond the end of the probe.

Max-i-Probe

These are designed to produces upward flushing motion for complete canal irrigation .Side port dispersal prevents solution and debris from being expressed through the apex Closed, rounded end reduces risk of apex damage.

Ultrasonic irrigationUltrasonics devices were first introduced in endodontics by Richman[ 1957]Two types of ultrasonics irrigation have been described in the literature;One where irrigation is combined with simultaneous ultrasonic instrumentationAnother without simultaneous instrumentation called passive ultrasonic irrigation.

Cavitation - Oscillation of gas / vapour filled bubbles in an acoustic fieldAcoustic microstreaming- Rapid movement of fluid around an oscillating instrument

Ultrasonic energy passes through the irrigating solution and exerts its acoustic streaming or scrubbing effect on the canal wall.

According to studies [Weber et al] there may be an advantage of interappointment medication with calcium hydroxide combined with passive ultrasonic activation with chlorhexidine.

This may provide patients with reduced interappointment flare-ups and decrease multiple visits to single appointments.

JOURNAL REVIEW

Effect of EDTA with and without surfactants or ultrasonics on removal of smear layer.Lui JN, Kuah HG, Chen NNJOE 2007

This study compared the in vitro efficacy of Smear Clear (Sybron Endo, CA), a 17% ethylenediaminetetraacetic acid (EDTA) solution with surfactants, to 17% EDTA, with and without the use of ultrasonics, in removal of the smear layer.

Addition of surfactants to EDTA in Smear Clear did not result in better smear layer removal. The use of ultrasonics with 17% EDTA improved smear layer removal.

Killing of Enterococcus faecalis by MTAD and chlorhexidine digluconate with or without cetrimide in the presence or absence of dentine powder or BSA.Portenier I, Waltimo T, rstavik D, Haapasalo M.JOE 2006.The antibacterial efficacy of irrigating solutions and local disinfectants used in endodontics appears poorer in vivo than in vitro. One explanation may be inactivation by compounds present in the root canal. MTAD (a mixture of tetracycline isomer, acid, and detergent) is a new root canal irrigation solution with antibacterial activity. The aim of this study was to investigate the antibacterial activity of MTAD and chlorhexidine towards two strains of Enterococcus faecalis and the inhibitory effects of dentine and bovine serum albumin on the antibacterial activity.

Full concentration (100%) MTAD and 0.2% chlorhexidine rapidly killed both strains. Combining chlorhexidine with cetrimide further reduced the time required for killing. The presence of dentine caused a marked delay in killing by both medicaments. The two E. faecalis strains tested showed minor differences in their susceptibility to the disinfectants.

Effects of Er:YAG and Nd:YAG laser irradiation on radicular dentine permeability using different irrigating solutions.Brugnera A, Zanin F, Barbin EL, Span JC, Santana R, Pcora JD.LAS SUR MED 2003

To evaluate the effect of Er:YAG and Nd:YAG laser on radicular dentine permeability when using distilled and deionized water and 1% NaClO as irrigating solutions.

CONCLUSIONS: The use of distilled and deionized water and Er:YAG laser showed the greater increase of dentine permeability. The use of 1% NaClO with Nd:YAG laser, distilled, and deionized water with Nd:YAG laser and the use of water increased dentine permeability less than the other groups. The use of 1% NaClO with and without Er:YAG laser application were positioned intermediately among the treatments.

Influence of irrigating needle-tip designs in removing bacteria inoculated into instrumented root canals measured using single-tube luminometer.Vinothkumar TS, Kavitha S, Lakshminarayanan L, Gomathi NS, Kumar V.JOE 2007This study tested the mechanical efficacy of various irrigating needle tip designs on bacteria inoculated into instrumented root canals. Root canals of 30 extracted permanent canines were prepared to size 60 at working length (WL) using ProFile 0.04 taper rotary nickel-titanium files. Root canals were autoclaved and inoculated with a 20-microl suspension (1.4 x 10(7) cells) of genetically engineered Escherichia coli pYUB556.

Safety-ended needles with single (group 1) and double (group 2) side-port and hypodermic needles (group 3) were used upto 1 mm short of WL. The percentage of bacteria remaining after irrigation was 67.9 +/- 9.5, 75.3 +/- 12.9 and 77.7 +/- 11.8 respectively (p < 0.05; Kruskal-Wallis) with no difference between group II and group III (p > 0.05; Mann-Whitney).

Irrigation using safety needles with single side port was significantly effective.

An in vitro evaluation of the irrigating characteristics of ultrasonic and subsonic handpieces and irrigating needles and probes.Kahn FH, Rosenberg PA, Gliksberg J.JOE 1995The objective of this in vitro study was to evaluate the efficacy of a variety of endodontic irrigating devices. This study utilized plastic blocks with artificial canals to simulate the clinical setting. The canals were instrumented, and red food dye was introduced into each canal. The blocks were placed in a jig to simulate maxillary and mandibular arch orientation.

Irrigation was performed with: (a) B-D 22-gauge needle; (b) Monoject Endodontic Needle 23 and 27 gauge; (c) Max-i-Probe 25-, 28-, and 30-gauge probes; (d) Cavi-Endo ultrasonic handpiece; and (e) Micromega 1500 subsonic handpiece.The Max-i-Probe probes were the most effective instrument used to clear dye from the simulated canals in both the mandibular and maxillary positions.

The Effect of Passive Ultrasonic Activation of 2%Chlorhexidine or 5.25% Sodium Hypochlorite Irrigant on Residual Antimicrobial Activity in Root CanalsCarol Diener Weber, DDS, MS, Scott B. McClanahanJOE 2003The purpose of this study was to evaluate the effect of passive ultrasonic activation of 2% chlorhexidine and 5.25% NaOCl irrigant on residual antimicrobial activity in root canals.

By using passive ultrasonic activation with chlorhexidine, perhaps the clinician would not need to spend additional time with an interappointment medication such as calcium hydroxide.

There may be an advantage of interappointment medication with calcium hydroxide combined with passive ultrasonic activation with chlorhexidine.

CONCLUSION

Many new materials and methods have recently been introduced to improve root canal debridement and to achieve root canal sterilization. Some of the new treatment modalities have been marketed to dentists, with the claim that it is possible to sterilize an infected root canal system,

However, bearing in mind the complex anatomy of the root canal system and the ability of microorganisms to survive under adverse conditions, it might be premature to believe that the total sterilization of the root canal system could be readily achieved. In the age of evidence-based dentistry, it is advisable to wait until quality independent data are available to support the use of such new technologies.