Root Canal Disinfection Lecture 3 PDF

Root canal disinfection Lecture 3, 4th level Irrigation  Mohammed Al-Khawlani  Assist. Professor Of Endodontics, Conservative Dept. Thamar Uni.  Chemomechanical Preparation To increase the efficacy of mechanical preparation and bacteria removal, instrume...

Root canal disinfection Lecture 3, 4th level Irrigation  Mohammed Al-Khawlani  Assist. Professor Of Endodontics, Conservative Dept. Thamar Uni.  Chemomechanical Preparation To increase the efficacy of mechanical preparation and bacteria removal, instrumentation must be supplemented with active irrigating solutions. Irrigation is defined as washing out a body cavity or wound with water or a medicated fluid. The objectives of irrigation are both mechanical and biologic. The mechanical objective involves flushing out debris, lubricating the canal, and dissolving organic and inorganic tissue. The biologic function of the irrigants is related to their antimicrobial effect. What is the rationale for the use of intracanal irrigants ?? The complexity of the root canal system bacterial invasion into dentinal tubules, lateral canals and anatomic complexities The physical limitations of metal instruments  Benefits of Using Irrigants in Root Canal Treatment ◆ Removal of particulate debris and wetting of the canal walls ◆ Destruction of microorganisms ◆ Dissolution of organic debris ◆ Opening of dentinal tubules by removal of the smear layer ◆ Disinfection and cleaning of areas inaccessible to endodontic instruments  What are the properties of an ideal irrigant ?? ◆ Be an effective germicide and fungicide ◆ Be nonirritating to the periapical tissues ◆ Have a prolonged antimicrobial effect ◆ Be active in the presence of blood, serum, and protein derivatives of tissue ◆ Have low surface tension ◆ Not interfere with healing of periapical tissues ◆ Not stain tooth structure ◆ Be able to remove the smear layer, and be able to disinfect the underlying dentin and its tubules ◆ Be nontoxic, and noncarcinogenic to tissue cells surrounding the tooth ◆ Have no adverse effects on the sealing ability of filling materials ◆ Be relatively inexpensive There’s No ideal irrigant so combination may be used Commonly used irrigants Sodium Hypochlorite Chlorohexidine Hydrogen peroxide Chelating agents (EDTA) MTAD Qmix  FACTORS THAT MODIFY ACTIVITY OF INTRACANAL IRRIGATING SOLUTIONS 1. Concentration: tissue dissolving ability of sodium hypochlorite is greater at a concentration of 5.2 % than at 2.5 % and 0.5 %. 2. Contact: To be effective, the intracanal agent must contact the substrate (i.e. organic tissue or microbes). 3. Presence of organic tissue: Presence of the organic tissues decreases the effectiveness of intracanal medicaments (protein coagulation results from the reaction between irrigant and O.T. barrier preventing penetration of irrigant), so the organic tissue must be removed mechanically or chemomechanically by simultaneous use of instruments and irrigating solutions. 4. Quantity of the irrigant used 5. Surface tension of irrigant 6. Temperature of the irrigant: NaOCl is more effective when it is warm 7. Frequency of irrigation 8. Canal diameter: Wider the canal, better is debridement action of irrigant. 9. Age of irrigant: Freshly prepared solutions are more efficient then older ones.  Normal saline No chemical action Can provide lubrication to root canals. acts by flushing action. used as final rinse for root canals to remove any chemical irrigant left after root canal preparation. Advantage It is biocompatible in nature. No adverse reaction even if extruded periapically because osmotic pressure of normal saline is same as that of the blood. Disadvantages Does not possess dissolution and disinfecting properties. Too mild to thoroughly clean the canals Does not possess antimicrobial activity Does not remove smear layer.  Sodium Hypochlorite NaOCl is a clear, pale, green-yellow liquid with strong odor of chlorine. The most popular irrigant decomposed by light. Concentration; From 0.5% up to 5.25% What are the merits of using sodium hypochlorite in endodontics ?? Sodium hypochlorite is used in endodontics at Concentrations of 0.5% to 5.25% for two main purposes: (i) Potent antimicrobial agent, it can rapidly kill vegetative bacteria, spore-forming bacteria, fungi, protozoa, viruses, and bacterial spores (ii) Has a tissue-dissolving proteolytic ability, it dissolves organic material such as pulp tissue and collagen  Methods to increase the efficacy of sodium hypochlorite 1. Time: Since antimicrobial effectiveness of sodium hypochlorite is directly related to its contact time with the canal, greater the contact time, more effective it is. This is especially important in necrotic cases. 2. Heat: It has been shown that warming sodium hypochlorite to 60-70°, increases its tissue dissolving properties. But one should be careful not to overheat the solution because this can cause breakdown of sodium hypochlorite constituents and thus may damage the solution. 3. Specialized irrigating syringes: Most researches have shown that unaided irrigation requires at least a size #25 apex for it to reach the more apical portions of canals. Newer specialized side venting endodontic syringes with narrower diameter (32 gauge) are available which aid in getting irrigant closer to apex and help the irrigant to move sideways 4. Ultrasonic activation: has also shown to accelerate chemical reaction and achieve a superior cleansing action Precautions to be Taken While Using Sodium Hypochlorite Toxixcity: 5.25 % NaOCl can cause serious damage to tissue if injected periapically. causes excruciating pain, periapical bleeding and swelling. medication like antibiotics, analgesics, antihistamine should be prescribed accordingly. In addition to these, reassurance of the Patient is recommended. Thus irrigation with sodium hypochlorite solution should always be performed passively especially in cases with larger apical diameters, also the syringe should be side vented. The needle should never be locked in the canal. Decreasing the concentration and increasing the irrigant volume, thus avoiding the danger of toxicity. Advantages of Sodium Hypochlorite Disadvantages 1. It causes tissue dissolution. 1. Because of high surface tension, its ability to wet 2. It has antibacterial and bleaching action. dentin is less. 3. Provide lubrication of canals. 2. Irritant to tissues, if extruded periapically, it can result 4. Economical. in severe cellular damage. 5. Easily available. 3. If comes in contact, it cause inflammation of gingiva because of its caustic nature. 4. It can bleach the clothes if spilt. 5. It has bad odor and taste. 6. Vapors of sodium hypochlorite can irritate the eyes. 7. It can be corrosive to instruments.  Use of Sodium Hypochlorite in Combination with other Medicaments The tissue dissolving capacity of sodium hypochlorite is found to be increased when tissue is pretreated with calcium hydroxide combination of calcium hydroxide and sodium hypochlorite was better than either of medicament alone. combination of sodium hypochlorite and EDTA has more bactericidal effect which is probably due to removal of contaminated smear layer by EDTA. The alternate use of sodium hypochlorite and chlorhexidine results in greater reduction of microflora than the use of either alone  Chlorhexidien Chlorhexidine is a broad spectrum antimicrobial agent. It is a potent antiseptic which is widely used for chemical plaque control in the oral cavity in concentrations of 0.2 % For using it as an irrigant, it should be used in concentration of 2 %. chlorhexidine has the property of substantivity (residual effect) for 72 hours or more. Advantages and Uses 1. 2 % solution is used as root irrigant in canals. 2. 0.2 % solution can be used in controlling plaque activity. 3. It is more effective on gram-positive bacteria than gram-negative bacteria. Disadvantages 1. It is not considered as the main irrigant in standard endodontic therapy. 2. It is unable to dissolve necrotic tissue remnants. 3. It is less effective on gram-negative than on gram-positive bacteria.  Hydrogen peroxide It is clear, odorless liquid. used in concentrations ranging from 1-30 % It dissociates into H2O + [O] (water and nascent oxygent). On coming in contact with tissue a liberated [O] produces bactericidal effect but this effect is transient and diminishes in presence of organic debris. release of [O] nascent oxygen on contact with organic tissue results in effervescence or bubbling action which aid in mechanical debridement by dislodging particles of necrotic tissue and dentinal debris and floating them to the surface. Use: It is used as an irrigating solution either alone or alternatively with sodium hypochlorite. The advantage of using alternating solutions of 3 % H2O2 and 5.2 % NaOCl are: 1. Effervescent reaction by Hydrogen peroxide bubbles pushes debris mechanically out of root canal. 2. Solvent action of sodium hypochlorite on organic debris. 3. Disinfecting and bleaching action by both solutions. When using in combination with sodium hypochlorite, always use sodium hypochlorite in the last because hydrogen peroxide can react with pulp debris and blood to produce gas (nascent oxygen) which builds up pressure on closing the tooth, this can result in severe post operative pain.  Chelating agents (EDTA) Chelating agent is defined as a chemical which combines with a metal to form chelate. EDTA= Ethylenediamine Tetra-Acetic Acid SMEAR LAYER ??? It is A layer covers the canal walls after Instrumentation. Is it necessary to remove smear layer?? Importance of smear layer removal: Contains microorganisms Permits close adaptation of endodontic filling, So decreasing leakage. EDTA and other chelating agents like citric acid, polyacrylic acids are used for removing the inorganic part. What about the organic part??? Functions of EDTA Lubrication Emulsification Holding debris in suspension Smear layer removal Uses of EDTA It has dentin dissolving properties It helps in enlarging narrow canals Makes easier manipulation of instruments Reduces time needed for debridement.  Different Forms of EDTA 1. R-EDTA: EDTA is combined with cetrimide. It helps to better cleaning the canals. 2. EDTAT: (EDTA + Texapon) EDTA is combined with sodium lauryl sulfate which results in decreasing the surface tension. 3. EDTA-C: It is commercially available as 15 % solution and pH of 7.3 under the name EDTAC because it contains cetavelon, a quaternary ammonium compound which has been added to it for its disinfecting properties. * A 5-minutes exposure of the root canal to EDTA would remove the smear layer and open the dentinal tubules to a depth of 20–30 μm * liquid-form chelators remove the smear layer better than the paste form MTAD (A Mixture of a Tetracycline Isomer, an Acid and a Detergent) The purpose of using MTAD is to: a. Disinfect the dentin b. Remove the smear layer c. Open the dentinal tubules and allow the antimicrobial agents to penetrate the entire root canal system. Composition a. Tetracycline: It is bacteriostatic broad spectrum antibiotic. It has low pH and acts as calcium chelator. It removes smear layer It has property of substanitivity It promotes healing. b. Citric acid: It is bactericidal in nature and removes smear layer. c. Detergent (Tween 80): It decreases surface tension. Advantages 1. It is an effective solution for removal of most of the smear layer. 2. It kills most significant bacterial stains, i.e. E faecalis which has been shown to resistant to many intracanal medicaments and irrigants 3. It is biocompatible 4. It has minimal effect on properties of teeth 5. MTAD has similar solubilizing effects on pulp and dentin to those of EDTA 6. The high binding affinity of doxycycline present in MTAD for dentin allows prolonged antibacterial effect (it’s the main difference between MTAD and EDTA).  QMiX It is recommended to be used at the end of instrumentation, after NaOCl irrigation. QMix contains a CHX-analog, Triclosan and EDTA as a decalcifying agent; it is intended as antimicrobial irrigant as well as an agent to remove canal wall smear layers and debris. NEWER IRRIGATING SOLUTIONS Electrochemically Activated Solution It is one of newer irrigant solution which is produced from the tap water and low concentrated salt solutions. The resulted solution is called super oxidized water Advantages of electrochemically activated solution: 1. Non-toxic to biological tissues. 2. Effective with wide range of microbial spectra. Ozonated Water shown to be powerful antimicrobial agent against bacteria, fungi, protozoa and viruses. Its advantages include: Its potency Ease of handling Lack of mutagenicity Rapid microbial effects  Photo Activated Disinfection (PAD) PAD is a fast, effective and minimally invasive disinfection system which is considered to kill more than 99.99 % of bacteria in the endodontic biofilm. Mechanism of PAD laser light is transmitted through the disposable fibro-optic tip to activate the PAD antibacterial solution (stain). Within 1-3 minutes, the PAD system eliminates more than 99.99 % bacteria found in root canals Advantages of PAD 1. It has shown to be the most effective antimicrobial agent. It can effectively kill gram-negative, gram-positive, aerobic and anaerobic bacteria, in other words it eliminates all types of bacteria. 2. It overcomes the problems of antibiotic resistance. 3. It can kill bacteria present in complex biofilm 4. PAD does not pose any thermal risk due to low power of PAD laser. 5. It does not cause any sensitization. 6. Neither the PAD solution nor its products are toxic to patients. METHODS OF IRRIGATION Although the technique of irrigation is simple and easy, still, care should be taken while irrigating with different syringes or system. Following points should be in mind while irrigating the canal: 1. The solution must be introduced slowly and passively into the canal. 2. Needle should never be wedged into the canal and should allow an adequate back- flow. 3. Blunted needle of 25 gauge or 27 gauge are preferred. 4. In case of small canals, deposit the solution in pulp chamber. Then file will carry the solution into the canal. To remove the excess fluid, either the aspirating syringe or 2 × 2 inches folded gauge pad is placed near the chamber. To further dry the canal, remove the residual solution with paper point 5. Canal size and shape are crucial for irrigation of the canal. For effective cleaning of apical area, the canals must be enlarged at least to size 35 6. Regardless of delivery system, irrigants must never be forcibly inserted into apical tissue rather gently placed into the canal. 7. For effective cleaning, the needle delivering the solution should be in close proximity to the material to be removed. 8. In case of large canals, the tip of needle should be introduced until resistance is felt, then withdraw the needle 2-3 mm away from that point and irrigate the canal passively. 9. In order to clean effectively in both anterior and posterior teeth canals, a bend of the needle is necessary to reach the optimum length of the canal. 10. Volume of irrigation solution is more important than concentration or type of irrigant.  Different Needle Designs Ideal properties of irrigating needle 1. Needle should be blunt. 2. It should allow back-flow. 3. It should be flexible. 4. Longer in length. 5. Easily available. 6. Cost-effective. 1. 27 gauge needle with Notched tip: This needle is preferred as its notched tip allows backflow of the solution and does not create pressure in the periapical area. So, it ensures optimum cleaning without damage to periapical area. 2. Needle with bevel: Needle with bevel if gets lodged into the canal, there is risk of forcing irrigant past the apex. 3. Monojet endodontic needle: This needle is also considered to be efficient one as the long blunt needles can be inserted to the full length of the canal to ensure optimum cleaning. The only drawback observed is that if needles are placed near to the periapical area, it can cause damage. 4. ProRinse probes: - It has closed-end and side vent. - It eliminates possibilities of puncture of the apical foramen. - Expression of fluid through the lumen creates turbulence around and beyond the end of the probe Precautions to be taken while irrigation 1. Avoid wedging the needle into the canal. 2. Avoid forcing the solution into the canal. 3. Avoid placing the needle beyond the apical area or very near to apical area 4. Avoid using larger gauge needle. 5. Avoid using metallic, autoclavable syringe as they more prone to breakage Lubricants Advantages of using labricants: 1. Lubricants facilitate file manipulation during cleaning and shaping. 2. They are an aid in initial canal negotiation, especially in small constricted canals without taper. 3. They reduce torsional forces on the instruments and decrease the potential for fracture. 1. Glycerin is a mild alcohol that is inexpensive, nontoxic, aseptic, and somewhat soluble. It is slightly soluble, permitting removal once it has completed its function 2. Soap liquid or topical anesthetic may also be used. However, liquid soap (unless sterile) may be contaminated with bacteria. 3. Paste lubricants It could contain chelators. Commercial preparations of EDTA usually contain lubricants (wax or glycerin). One advantage of paste lubricants is that they can suspend dentinal debris and prevent canal blockage.  Paste lubricant limitations lubricants containing EDTA should be used with caution:  when one is negotiating a tight canal; EDTA may soften the walls slightly, thus permitting the file tips to gouge and ledge.  EDTA compounds appears could deactivate NaOCl by reducing the available chlorine.  In fact, softening agents (EDTA) could slightly alter the dentine walls, thereby limiting the ability of instruments to be guided along hard dentine.  If these softening chemicals are used, they should be placed in canals only after instruments have been used to length and the canal preparation has been started.  As a further precaution, these chemicals should not remain in the canal for any period of time without instrumentation.  Lubricants Usage A small amount can be placed along the shaft of the file or deposited in the canal orifice. Counterclockwise rotation of the file carries the material apically. The file can then be worked to length using a watch winding or “twiddling” motion.  Desiccants  Concentrated solutions of 70% to 90% alcohol (methanol or ethanol) may be used as a final irrigant to dry the canal and remove traces of other chemicals.  The same irrigating syringe used in the same manner as that used for chemical irrigation is indicated for alcohol.  Only a small amount of alcohol (1 to 2 ml per canal) is needed.