Irrigation information

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  Posted by: Dental Design      27th November 2024

The main aim of endodontic treatment is to eradicate infection while also reducing the risk of reinfection.[i] Endodontic irrigation, with the use of antimicrobial fluid and mechanical instrumentation, followed by complete obturation, is an essential part of the endodontic process to assure a beneficial environment for healing.[ii]

Chemical irrigation is the only reliable method currently available to reach areas potentially untouched by files.[iii] Irrigation helps to prevent the accumulation of infected debris into the apical root canal, lessening the risk of bacteria extruding into the periapical tissues.[iv] The hard tissue debris caused by instrumentation – the smear layer – requires additional consideration during the irrigation process to prevent reinfection.ⁱ

As well as cleaning and disinfecting the infected root, irrigants have the additional benefit of reducing friction between the instrument and dentine, improving the file’s cutting effectiveness while reducing the risk of thermal irritation for the patient.ⁱ

Some of the chemical processes behind irrigants

Sodium hypochlorite (NaOCl) – the most commonly used irrigant[v] – is the strong alkali known as bleach. The solution has a powerful antimicrobial effect, and is currently the only irrigant available that can also dissolve organic matter in the canal.ⁱⁱ

The solution is successful in removing necrotic tissue as well as biofilm – debriding, flushing and disinfecting hard-to-reach areas of the canals.ⁱ The speed of tissue dissolution can be increased with agitation and refreshment, and irrigation with a NaOCl solution (up to 6%[vi]) between each file is recommended during the entire instrumentation process. Sodium hypochlorite remains the primary irrigant of choice, but – after flushing with distilled water to prevent an unwanted chemical reaction[vii] – it needs to be followed by a further chelating chemical product to remove the smear layer.^iv  

The thick smear layer is comprised of infected tissue debris created during the instrumentation process of the infected root canal.ⁱⁱ If not removed, the infected smear layer can also impair adhesion of obturation material to the canal wall.[viii]

A chelator bonds to metal ions, taking them out of a solution, diminishing their reactivity. Ethylenediaminetetraacetic acid (EDTA) is an effective calcium chelator, widely used in a number of different industries, including systemic medicine as a treatment for heavy metal poisoning.[ix] It can disrupt and remove minerals from the smear layer as well as debris from the root canal wall.[x] When introduced after the use of NaOCl,[xi] EDTA has been shown in multiple studies to be effective in eliminating smear.[xii]

Chlorhexidine (CHX) is used in commercial mouthwashes and topical disinfectants. It can be applied in all phases of endodontic treatment, but due to potential chemical reactions, should be used with caution. CHX must be removed with a solution of distilled water before using EDTA, and NcOCl must be effectively removed before using CHX with saline or alcohol due to unwanted and potentially harmful chemical by-products.[xiii]

Avoiding the vapour lock effect

The vapour lock effect occurs when air or a gas bubble enters or is formed inside the root canal during the endodontic process. These can limit the efficacy of irrigants by blocking access to infected tissue.[xiv]

Among the solutions for the removal of a vapour lock, Manual Dynamic Agitation (MDA) has been described as a simple and low-cost technique for both activating the irrigant, and effectively reducing the occurrence of and removing air bubbles.^xii  A process known as positive pressure irrigation uses turbulence caused by the introduction of liquid into the root to disrupt the vapour lock. This is achieved with a syringe and side-vented needle to prevent overfilling the canal.[xv] Passive Ultrasonic Irrigation (PUI) is another solution, that makes use of microvibrations to activate irrigants. However, some studies have shown MDA to be more effective in reducing or removing vapour lock.^xiv

As above, flushing with distilled water between NaOCl and EDTA chemical treatments is recommended to prevent the formation of chlorine gas bubbles.^v To prevent this from occurring, it is further recommended that clinicians use well-labelled syringes to prevent mistakes.^vi

Innovative solutions

The CanalPro^® range from COLTENE covers the entire endodontic procedure, including irrigation protocols. Available in 27 or 30 gauge, with slotted and side-vented designs, CanalPro^® Irrigation Tips are ideal for canals, pockets and fistulas. With a safe and quick syringe-filling, and colour coded syringe system for ease of use, the CanalPro^® Endodontic Irrigation System incorporates NaOCl for irrigation and debridement, available in a 6% and 3% formula. CanalPro^® EDTA 17% solution removes the smear layer, opening dentine tubules for optimal disinfection and adhesion. CanalPro^® CHX 2% solution uses a patent-pending formula for additional rinsing, to provide exceptional, long-lasting cleansing.

 Chemical irrigation is a crucial step in eliminating infection as part of the root canal treatment  process, resulting in more successful treatment and saving patients from further infection. Using systems that simplify and clarify the process is great for clinicians, meaning great results for patients.

 

For more on COLTENE, visit https://colteneuk.com/IRRIGATION,
email info.uk@coltene.com or call 0800 254 5115.

 

Author: Nic Coomber, National Account Manager & Marketing Strategist at Coltene.

 

[i] Maryam Pourhajibagher, Abbas bahador, Adjunctive antimicrobial photodynamic therapy to conventional chemo-mechanical debridement of infected root canal systems: A systematic review and meta-analysis, Photodiagnosis and Photodynamic Therapy, Volume 26, 2019, Pages 19-26, ISSN 1572-1000, https://doi.org/10.1016/j.pdpdt.2019.02.009.

[ii] Haapasalo, M., Shen, Y., Wang, Z. et al. Irrigation in endodontics. Br Dent J 216, 299–303 (2014). https://doi.org/10.1038/sj.bdj.2014.204

[iii] Tashkandi N, Alghamdi F. Effect of Chemical Debridement and Irrigant Activation on Endodontic Treatment Outcomes: An Updated Overview. Cureus. 2022 Jan 23;14(1):e21525. doi: 10.7759/cureus.21525. PMID: 35223300; PMCID: PMC8863357.

[iv] Park E, Shen Y, Haapasalo M . Irrigation of the apical root canal. Endodontic Topics 2012; 27: 54–73.

[v] Boutsioukis C, Arias-Moliz MT. Present status and future directions – irrigants and irrigation methods. Int Endod J. 2022 May;55 Suppl 3(Suppl 3):588-612. doi: 10.1111/iej.13739. Epub 2022 Apr 6. PMID: 35338652; PMCID: PMC9321999.

[vi] Arruda-Vasconcelos R, Barbosa-Ribeiro M, Louzada LM, Lemos BIN, de-Jesus-Soares A, Ferraz CCR, Almeida JFA, Marciano MA, Gomes BPFA. Efficacy of 6% Sodium Hypochlorite on Infectious Content of Teeth with Symptomatic Irreversible Pulpitis. J Endod. 2022 Feb;48(2):179-189. doi: 10.1016/j.joen.2021.11.002. Epub 2021 Dec 16. PMID: 34921849.

[vii] Wright PP, Kahler B, Walsh LJ. Alkaline Sodium Hypochlorite Irrigant and Its Chemical Interactions. Materials (Basel). 2017 Sep 29;10(10):1147. doi: 10.3390/ma10101147. PMID: 28961175; PMCID: PMC5666953.

[viii] Darcey J, Taylor D, Roudsari RV, Hunter M. Modern Endodontic Principles Part 4: Irrigation Article  in  Dental Update · February 2016 DOI: 10.12968/denu.2016.43.1.20

[ix] DeBusk, Ruth; et al. (2002). “Ethylenediaminetetraacetic acid (EDTA)”. University of Maryland Medical Center. Archived from the original on 2007-05-04.

[x] Zou, X., Zheng, X., Liang, Y. et al. Expert consensus on irrigation and intracanal medication in root canal therapy. Int J Oral Sci 16, 23 (2024). https://doi.org/10.1038/s41368-024-00280-5

[xi] Haapasalo M, Qian W, Shen Y . Irrigation: beyond the smear layer. Endodontic Topics 2012; 27: 35–53.

[xii] Mohammadi Z, Shalavi S, Jafarzadeh H. Ethylenediaminetetraacetic acid in endodontics. Eur J Dent. 2013 Sep;7(Suppl 1):S135-S142. doi: 10.4103/1305-7456.119091. PMID: 24966721; PMCID: PMC4054072.

[xiii] Drews DJ, Nguyen AD, Diederich A, Gernhardt CR. The Interaction of Two Widely Used Endodontic Irrigants, Chlorhexidine and Sodium Hypochlorite, and Its Impact on the Disinfection Protocol during Root Canal Treatment. Antibiotics (Basel). 2023 Mar 16;12(3):589. doi: 10.3390/antibiotics12030589. PMID: 36978457; PMCID: PMC10044599.

[xiv] Dioguardi M, Crincoli V, Sovereto D, Caloro GA, Aiuto R, Illuzzi G, Caponio VCA, Troiano G, De Lillo A, Ciavarella D, et al. Effectiveness of Vapor Lock Effect Removal in Endo Training Blocks: Manual Dynamic Agitation versus Passive Ultrasonic Irrigation. Applied Sciences. 2019; 9(24):5411. https://doi.org/10.3390/app9245411

[xv] KhareM, Suprabha BS, Yadav A, Shenoy R, Boaz K, Rao A. Effectiveness of Ultrasonic and Manual Dynamic Agitation Techniques in Irrigant Penetration: An in vitro Study. World Journal of Dentistry, May-June 2017;8(3):207-212. 10.5005/jp-journals-10015-1439

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