Disinfection of Root Canal System PDF

Assist. Prof. Dr. Dilan KIRMIZI Endodontics Department DISINFECTION of ROOT CANAL SYSTEM Learning Objectives of This Course: At the end of this course, students should be able to:  list the bacterial colonization ways in the root canal system and indications for using intracanal medication in end...

Assist. Prof. Dr. Dilan KIRMIZI Endodontics Department DISINFECTION of ROOT CANAL SYSTEM Learning Objectives of This Course: At the end of this course, students should be able to:  list the bacterial colonization ways in the root canal system and indications for using intracanal medication in endodontic treatment,  classify the different types of intracanal medicaments and choose the appropriate one depending on their properties and modes of action in clinical use,  list the application protocols, criteria to be considered, side effects and possible complications of preferred medications in clinical use. Disinfectant, meanwhile, is defined as “an agent that destroys or inhibits the activity of microorganisms that cause disease”. Culture-dependent or culture-independent (molecular) and histobacteriological studies have revealed that bacteria can persist in the root canal system after chemomechanical preparation in 40% to 60% of cases. Bacteria that survive the effects of instruments and irrigants are often found in areas that are difficult or impossible to reach during chemomechanical preparation.  Untouched Root Canal Walls: If untouched canal walls are covered by a bacterial biofilm, there is a risk that bacteria will persist after chemo-mechanical preparation, especially if sodium hypochlorite irrigant did not manage to reach these areas or is not present in the canal for a sufficiently long duration to eliminate the biofilm. Reasons of untouched root canal walls:    The difference of size of the apical preparation and the original canal diameter. Irregular, flattened, kidney-shaped, or oval in cross-section of the canal morphology. Different preparation techniques. 1  Isthmuses, Lateral Canals and Apical Ramifications: Isthmuses have been observed at the apical 3 mm of 80% to 90% of molar roots. Ramifications may be observed anywhere along the length of the root, but they occur more frequently in the apical portion and in posterior teeth.  Dentinal Tubules: Bacterial invasion of the dentinal tubules can occur in most of canals in teeth with apical periodontitis. Bacterial cells penetrating deep into tubules are unlikely to be eliminated by chemomechanical preparation procedures. Irrigation solutions, such as sodium hypochlorite and chlorhexidine, have pronounced antimicrobial activities and are effective against a broad spectrum of microbial species usually found in infected root canals. The efficacy of irrigation solutions is observed when optimal contact with microbial cells is achieved, but the shorter residence time of these agents in the root canal system (10-30 minutes) is often a limiting factor. Therefore, there is a preference for inter-appointment intracanal medicament administration (7 or more days) to ensure longer contact. This significant time difference may alter the effectiveness of bacterial elimination, especially in the expectation that the antimicrobial agent will diffuse to sites distant from the main root canal. A. The Main Objectives for the Intracanal Medication      Restrict bacterial regrowth Supply continued disinfection Create a physical barrier against microleakage Elimination of postoperative pain Enhancement of anesthetic effect B. Possible Side Effects of Intracanal Medications      Irritation due to cytotoxicity Hypersensitivity Self-inhibition Discoloration of tooth tissues Fixed necrotic tissue may decrease the effectiveness of irrigation solution 2  Some medicaments may cause less dissolution of fixed tissue in irrigant solution, especially those which can make fixation. C. Ideal Intracanal Medication Features           Have a bactericidal or bacteriostatic effect Have a quick effect and for long-term Diffuse and penetrate into the tooth structure Prevent the adhesion of microorganisms Stimulate periapical repair Avoid or reduce the pain Be cheap and have a long shelf life Not to cause discoloration Not to be affected by the exudates Not to cause irritation D. Types of Intracanal Medicaments ALDEHYDES •Formocresol •Glutaraldehyde PHENOLS •Eugenol •Camphorated phenol •Camphorated paramonochlorophenol •Cresatin •Cresol •Thymol HALOGENS •Sodium hypochlorite •Iodine potassium iodide •Iodoform OTHERS •Calcium hydroxide •Chlorhexidine ANTIBIOTICS •Penicillin •Minocycline •Metronidazole •Clindamycin •Doxycycline •Demeclocycline ANTIINFLAMMATORY DRUGS •Corticosteroids, nonsteroidal antiinflammatory drugs 3 1. Calcium Hydroxide (Ca(OH)₂)  Calcium hydroxide is the most popular antibacterial intracanal medicament.  It is an inorganic compound and the most common presentation is in the form of an odorless white powder. In the presence of water, it dissociates into hydroxyl and calcium ions.  Most of its biological effects are related to its alkaline pH (12,5) and due to the hydroxyl ions.  Calcium hydroxide has to be placed into the entire length of the prepared root canal to exert its maximal effects.  Although some clinicians have developed methods of placing calcium hydroxide powder into the canal; placement is easier, more reliable and the canal better filled when calcium hydroxide is mixed with a liquid, gel, creamy carrier or vehicle. Aqueous  Viscous - Distilled water - Glycerine - Saline - Polyethyleneglycol - Dental anaesthetic solution - Propyleneglycol Oily - Camphorated paramonochlorophenol - Olive oil - Silicone oil As the effects of calcium hydroxide are dependent on the pH reached around where it has been placed, if the ionic release is slow, it may be unable to exert its intended effects.  It is questionable if viscous or oily vehicles are of any value since they do not permit rapid dissociation and consequently, a high release of hydroxyl ions.  Mostly biocompatible vehicles (such as distilled water, saline, anesthetic solution and glycerin) reduce the antimicrobial effect of calcium hydroxide.  Long-term use, preferably with changes of the calcium hydroxide, is necessary to maximize disinfection of the root canal system.  Another option is to combine calcium hydroxide with biologically active vehicles (such as; Chlorhexidine, Iodine potassium iodide, Ledermix, Odontopaste). 4  Biological advantages of Ca(OH)₂: 1. 2. 3. 4. 5. 6. 7. Biocompatible. Microbial control Promotes healing of periapical tissue. Inhibit root resorption. Has hemorrhagic control effect. Dissolve organic remnants Stimulate hard tissue formation  Disadvantages of Ca(OH)₂: 1. 2. 3. 4. Has limited effect with short-term use. Tissue residues and dentin debris modify its effect. Particularly difficult to remove from curved channels. Since it is difficult to remove from the apical parts of the canals, it may adversely affect the penetration of root canal sealers into the dentinal tubules. 5. Has low effect against Entorococcus faecalis and Candida albicans. 6. Can not eliminate all microorganisms from the canal. 7. Causes root fragile if remains for long-term in the canal.  Calcium Hydroxide Forms: - Powder and liquid Two paste system (one base paste another catalyst paste) Single paste (visible light) 2. Chlorhexidine  Chlorhexidine has been widely used as a topical antiseptic solution, and effective concentrations range from 0,12% to 2%.  Chlorhexidine is highly effective against several gram-positive and gram-negative oral bacterial species as well as yeasts.  Depending on the concentration, chlorhexidine may be bacteriostatic or bactericidal.  As an intracanal medicament, chlorhexidine gluconate gel has been shown in vitro to be more effective than calcium hydroxide in disinfecting dentinal tubules. However, clinical studies found no difference in the incidence of postoperative pain in treatment, or retreatment, cases after intracanal medication with either chlorhexidine or calcium hydroxide. 5 3. Antibiotics  Antibiotics are naturally occurring substances of microbial origin, or synthetic, or semisynthetic, substances that exhibit antimicrobial activity in low concentrations by killing, or inhibiting the growth of, selective microorganisms.  Since antibiotics used systemically, or topically, are usually successful in treating infections in the body, their use as topical antimicrobial agents in root canal treatment was suggested. The main concerns about using antibiotics as intracanal medicaments include the possibility of: - Sensitization: The patient is sensitized to that drug and becomes predisposed to further allergic reactions when in contact with the same drug for another purpose. - Development of resistant strains: Inappropriate use of antibiotics should be avoided because of the risk of bacterial strains becoming resistant. - Limited spectrum: There is no antibiotic is effective against all endodontic pathogens. Antibiotics have a more restricted spectrum of activity and hence may be ineffective against all pathogens involved. The most commonly used antibiotic preparations as intracanal medication: • Septomixin B (Neomicine + polimixin B sulphate) • Ledermix (Tetracycline+ Demeklocyline HCl + Corticosteroid) • Triple Antibiotic Paste (Metronidazole + Ciprofloxacin + Minocycline) Triple Antibiotic Paste:  Triple antibiotic paste is a combination of three antibiotics namely minocycline (100mg), ciprofloxacin (200mg), metronidazole (500mg) and propylene glycol, saline as carrier.  Triple antibiotic powder mixed with either normal saline or 2% chlorhexidine, produced the largest zone of inhibition against E. Faecalis.  Minocycline can cause discoloration of the crown. Used in root-end open teeth and in revascularization procedures in patients with apical periodontitis and causes disinfected environment for the regenerative cells development. 6 4. Other Intracanal Medicaments  In the past, several toxic substances, including aldehydes and phenols have been used as intracanal medicaments.  Most are toxic to host tissues, some are allergenic and may even be carcinogenic; some are ineffective in clinical practice.  Consequently, the use of most of these substances has been discontinued and they are no longer recommended. E. Intracanal Medicament Application  Instruments Used to Insert the Medicament Into the Canal  Syringe: Probably, the easiest way of applying a medicament.  Disposable plastic tips: There is no risk of cross-infection.  File  Gutta Percha  Spiral Fillers: Can bind on the canal walls and fracture. The direction of rotation must be verified before use. Perhaps it is easiest to use spiral fillers by hand; but they do not really offer over applying medicament with a hand instrument. Usage of lentulo should be in clockwise at the lowest speed. Antibiotics and steroids are used in the form of paste. They are inserted into the canal with lentulo or their special cannulas.  Intracanal Calcium Hydroxide Application: Calcium hydroxide used as an intracanal medication is available as powder and liquid or injectable form. The injectable form of the medication is easy to use intra-canal. 7 If the calcium hydroxide to be used as If the calcium hydroxide to be used as intracanal medication is in powder and liquid intracanal medication is in injectable form: form:   Mix the powder calcium hydroxide with the  Insert the injectable calcium hydroxide liquid form vehicle to a creamy consistency. syringe into the canal without compression Send the entire paste into the canal from and pressure, and the paste is sent into the apical to coronal to completely cover the canal canal from apical to coronal direction to walls by an instrument smaller than the completely cover the canal walls. diameter of the canal (such as lentulo, pastinject).  Remove excess paste from the canal orifice.  Close the canal orifice with a small cotton pellet or teflon  Seal the access cavity with temporary filling material At least a week after this application;  The temporary filling is removed, canal preparation and irrigation is performed to remove the calcium hydroxide in the root canal (if necessary, the procedure can be repeated and the dressing is renewed). Before the canal obturation stage;  Remove intra-canal calcium hydroxide from the root canal. Do not over flow root canal medicament from apex. If you overflow the calcium hydroxide from the apex of the first mandibular premolar, nerve will be effected then patient will have the feeling of being (numbness) anesthetized. Sometimes calcium hydroxide can be overflow to mandibular canal and then affect the mandibular nerve. This case is going to be more difficult to deal with.  Calcium Hydroxide Residence Time in the Canal:  Calcium Hydroxide aqueous solution must stay at least for one week.  Viscous and oily solutions can stay 2 – 4 month. 8  Removal of Calcium Hydroxide: Removal of calcium hydroxide is done by instrumentation and activation of irrigation solutions from the root canal by using NaOCl and EDTA. However, calcium hydroxide can not be completely removed from the canal with any method. According to some studies in the literature, it has been reported that calcium hydroxide residues in the root canal have negative effects on root canal filling material, root canal paste. REFERENCES Alaçam T, Alaçam A, Aydın M, et al. Endodonti. Mimtaş Yay.; 2012. Berman, L. H., & Hargreaves, K. M. (2020). Cohen's pathways of the pulp-e-book. Elsevier Health Sciences Delgado RJ, Gasparoto TH, Sipert CR, et al. Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans. International Journal of Oral Science 2013;5:32–6. Delgado RJ, Gasparoto TH, Sipert CR, et al. Antimicrobial effects of calcium hydroxide and chlorhexidine on Enterococcus faecalis. Journal of Endodontics 2010;36:1389–93. Fava LR, Saunders WP. Calcium hydroxide pastes: classification and clinical indications. International Endodontic Journal 1999;32:257–82. Ghabraei S, Bolhari B, Yaghoobnejad F, Meraji N. 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