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Year : 2019  |  Volume : 9  |  Issue : 3  |  Page : 235-236

Shape optimal and clean more

Department of Conservative Dentistry and Endodontics, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India

Date of Web Publication16-Aug-2019

Correspondence Address:
Dr. Sindhu Ramesh
Department of Conservative Dentistry and Endodontics, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, 162, Poonamallee High Road, Chennai - 600 077, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/sej.sej_72_19

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How to cite this article:
Teja KV, Ramesh S. Shape optimal and clean more. Saudi Endod J 2019;9:235-6

How to cite this URL:
Teja KV, Ramesh S. Shape optimal and clean more. Saudi Endod J [serial online] 2019 [cited 2023 Apr 1];9:235-6. Available from: https://www.saudiendodj.com/text.asp?2019/9/3/235/264648


Emphasis on the term disinfection is beneficial than cleaning. It can only be achieved by root canal disinfectants rather than saline. Saline can provide a flush out of debris and not the disinfection. Hence, the usage of disinfectants for irrigation is mandatory and universally accepted.

The major hurdle in root canal disinfection is the removal of the bacterial biofilm. The only way to achieve optimal removal is by following a proper irrigation protocol and final irrigant activation. Manual syringe needle irrigation alone cannot remove the tightly adherent bacterial biofilm from the root canal walls.[1]

An ideal irrigant should have a broadspectrum antimicrobial activity, able to dissolve pulpal and necrotic tissue, remove organic and inorganic smear layer, be an effective lubricant during instrumentation of root canals, reduce bacterial endotoxin levels and be least cytotoxic. Effective root canal disinfection is adequately achieved with the use of sodium hypochlorite. The reactionary chloramine formed by sodium hypochlorite will interfere with cell metabolism and inhibit the irreversible oxidation of bacterial enzyme.

A surgeon is always cautious in removing all the remnants of the linings of the pathological lesion or will be very careful in inspecting its margins after removing it. Because any remnant that is left is going to cause further future progression and regrowth or recurrence of the lesion. The same applies in root canal infections where any remnant microbe in the root canal is going to be a causative factor for future reinfection.[2] But still, we give preference to sealing off the left out microbes with a thick radiopaque filling. Although complete removal of bacteria and its contents from root canal system is never achievable atleast emphasis should be made on optimal disinfection.

The previous concept was “shape more to clean more.” However, the reality is shape should be optimal to clean more, given that no optimal large size has ever been defined[3] Because it is ultimately the irrigant that has to reach the apical terminus and penetrate into all irregularities of the root canal. Hence, the shaping should be optimal so that the irrigating syringe needle reaches till the working length. Care should be taken not to irritate/injure the periradicular tissue.

Few points on most widely used irrigants:[4]

  • The currently available evidence is strongly in favor of sodium hypochlorite as the main endodontic irrigant
  • The optimal time that a hypochlorite irrigant at a given concentration needs to remain in the root canal system is still an issue yet to be solved
  • Although sodium hypochlorite appears to be the most desirable single endodontic irrigant, it cannot dissolve inorganic dentin particles and remove the smear layer. Hence, ethylenediaminetetraacetic acid (EDTA) is recommended as an adjuvant irrigant[5]
  • Gram-positive organisms such as Enterococci are mostly encountered in secondary endodontic infections. Hence, the use of chlorhexidine as an adjunctive final irrigant is appropriate in such cases
  • Although chlorhexidine is effective on Gram-positive organisms, it is less effective in case of primary endodontic infections, which are usually polymicrobial and predominated by Gram-negative anaerobes. Hence, the usage of sodium hypochlorite is mandatory as a primary root canal irrigant and is universally accepted.

Suggested irrigation regimen:

  • During instrumentation, irrigation is carried out intermittently with 5.25% sodium hypochlorite 1–2 mm short of the apex to prevent apical extrusion of irrigant
  • Use a 5 ml of disposable plastic syringe with a 31G side vented irrigation needle with double port for irrigation. Computational fluid dynamic analysis has reported that the tip design of irrigation needle greatly influences the flow of the irrigant. The side-vented needle has shown to minimize the risk of irrigant extrusion. Intermittent flush with saline after each irrigant usage is advised to prevent the precipitate formation
  • 17% EDTA solution has to be used in the canal to dissolve inorganic dentin particles as it has an excellent ability to remove the inorganic smear layer. Each canal needs to be irrigated with 1 ml of EDTA, but prolonged use may lead to the weakening of root dentin followed by 2 ml of chlorhexidine irrigation and final flush with 5 ml of saline or distilled water to clear off the residues of the irrigant used
  • Final irrigant activation is mandatory once the complete irrigation protocol is followed. Although conventional syringe needle irrigation reduces maximal bacterial colony-forming unit counts in the root canal, the only way to remove the tightly adherent bacterial biofilm and pulp tissue from inaccessible areas of the canals is by final irrigant activation
  • Various devices work on using sonic, ultrasonic, and laser-activated irrigation regimens. But still, there is an inambigutiy on the superiority of the devices and usage of specific activation device, for a given situation.[6] However, most of the activation methods employ almost similar technique by using 5.25% of sodium hypochlorite activation for 1–3 min followed by activation of 17% EDTA liquid for 30–60 s and finally agitating the canals with 2 ml of sterile water before obturating the canals.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Layton G, Wu WI, Selvaganapathy PR, Friedman S, Kishen A. Fluid dynamics and biofilm removal generated by syringe-delivered and 2 ultrasonic-assisted irrigation methods: A novel experimental approach. J Endod 2015;41:884-9.  Back to cited text no. 1
Gomes BP, Martinho FC, Vianna ME. Comparison of 2.5% sodium hypochlorite and 2% chlorhexidine gel on oral bacterial lipopolysaccharide reduction from primarily infected root canals. J Endod 2009;35:1350-3.  Back to cited text no. 2
Lee OY, Khan K, Li KY, Shetty H, Abiad RS, Cheung GS, et al. Influence of apical preparation size and irrigation technique on root canal debridement: A histological analysis of round and oval root canals. Int Endod J 2019. https://doi.org/10.1111/iej.13127.  Back to cited text no. 3
Zehnder M. Root canal irrigants. J Endod 2006;32:389-98.  Back to cited text no. 4
Ruddle CJ. Endodontic disinfection: Tsunami irrigation. Saudi Endod J 2015;5:1-12.  Back to cited text no. 5
  [Full text]  
Virdee SS, Seymour DW, Farnell D, Bhamra G, Bhakta S. Efficacy of irrigant activation techniques in removing intracanal smear layer and debris from mature permanent teeth: A systematic review and meta-analysis. Int Endod J 2018;51:605-21.  Back to cited text no. 6


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