: 2017  |  Volume : 29  |  Issue : 2  |  Page : 156--159

Effect of different methods of agitation on penetration of an endodontic irrigant

Sanjeev Srivastava, Mitali Kukreja, Smriti Kharbanda, Rohit Grover, Ajay Paliwal 
 Department of Conservative Dentistry and Endodontics, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India

Correspondence Address:
Sanjeev Srivastava
Flat No. 310, Ashoka Appartments, 5 Way Lane, Lucknow - 226 001, Uttar Pradesh


Objective: To assess the influence of different agitation protocols on the penetration of an endodontic irrigating solution into dentinal tubules. Materials and Methods: Forty extracted single-rooted human teeth were cleaned and shaped using nickel-titanium instrumentation with intermittent irrigation. Final rinse was performed using 5% sodium hypochlorite labeled with 0.2% alizarin red dye. Specimens were randomly assigned to four groups (n = 10), namely, control group (no agitation), K-file group, EndoActivator group, and endosonic group. Specimens were then sectioned at 2, 4, and 6 mm from the apex in 40 μm thick sections and prepared for fluorescence microscopy at ×100. Irrigation penetration was analyzed using Kruskal–Wallis analysis of variance followed by post hoc comparisons. Results: Groups were ranked in the following order: control (no agitation) ~K-file < EndoActivator < endosonic. Conclusion: Ultrasonic agitation increases penetration of endodontic irrigant into the dentinal tubules.

How to cite this article:
Srivastava S, Kukreja M, Kharbanda S, Grover R, Paliwal A. Effect of different methods of agitation on penetration of an endodontic irrigant.Endodontology 2017;29:156-159

How to cite this URL:
Srivastava S, Kukreja M, Kharbanda S, Grover R, Paliwal A. Effect of different methods of agitation on penetration of an endodontic irrigant. Endodontology [serial online] 2017 [cited 2022 Nov 30 ];29:156-159
Available from: https://www.endodontologyonweb.org/text.asp?2017/29/2/156/217715

Full Text


Successful outcome of endodontic treatment is dependent on thorough removal of infected/necrotic pulp tissue, microorganisms, and their toxin products.[1] This can be achieved by chemomechanical debridement of canals. However, intricate nature of root canals, severe complexities, and numerous variations in number and shape of canals poses serious challenges to chemomechanical debridement efforts.[2],[3],[4] Irrigation is an indispensable aid to mechanical preparation as it allows for cleaning in areas such as cul-de-sacs, isthmus, fins, and lateral canals which are not accessible to cleaning even after the use of contemporary endodontic file systems.[5],[6]

Among the irrigants in use, sodium hypochlorite (NaOCl) is the most commonly used and offers the advantage of not only dissolving the necrotic tissues and organic component of smear layer but also deactivating endotoxins as well as killing endodontic microorganisms present in biofilms and dentinal tubules.[7],[8],[9],[10] To enhance the effectiveness of irrigants, constant efforts are made to improve on irrigant delivery methods and different agitation protocols have been proposed.[11],[12],[13]

The aim of this study was to evaluate the penetration depth of 5% NaOCl into dentinal tubules while using different agitation protocols.

 Materials and Methods

A study protocol was designed and approval was obtained from the University Ethical Committee. Forty recently extracted single-rooted human teeth with noncurved canal were selected for the study (n = 40). Teeth shorter than 20 mm, with open apex, or teeth with caries or fractures were excluded from the study. All teeth were used within 1 month of extraction and sterile saline was used as the storage medium.

Crown structure 2.0 mm coronal to cementoenamel junction was removed using a saw with copious irrigation. A standardized canal instrumentation protocol was established.[14] Working length was established using a size 10 K-file. The file was inserted till it is seen through the apical foramen and 0.5 mm was deducted from it to arrive at the appropriate working length. Nickel-titanium rotary instruments (ProTaper, Dentsply Maillefer, Ballaigues, Switzerland) were used to shape the canals. The last file used at working length was F3. During instrumentation, irrigation was performed with 5% NaOCl using a 30-gauge endodontic needle (Perio/Endo Irrigation Needle, Biaggio, Switzerland). Following irrigation, 3 mL of 17% ethylenediaminetetraacetic acid was used for 2 min to remove smear layer followed by 3 mL of sterile saline.

The prepared teeth were randomly assigned to four groups (n = 10 for each group). The groups included: control group (no agitation), K-file group, EndoActivator (Dentsply Tulsa Dental Specialties, Tulsa, OK, USA) group, and endosonic group (Passive Ultrasonic IrriSafe, Satelec Acteon Group, Merignac, France). Wax was used to cover the apical foramen from outside to prevent irrigant from dripping out of the apex. A gutta-percha cone at working length was used to prevent wax from blocking the apex while setting. The cone was removed once the wax had set. Five milliliter of 5% NaOCl labeled with 0.2% alizarin red was used to perform the final rinse, using the 30-gauge endodontic needle keeping it 5 mm short from the working length. Each group had a different agitation protocol during final rinse.

No agitation was performed for the control group. Thus, control group was comprised 5% NaOCl with 0.2% alizarin red without activation. The K-file group included agitation with a size 10 K-file. As a part of agitation protocol, twenty up and down movements were performed up to the working length. The EndoActivator group included agitation at 10,000 cpm for 20 s. Finally, the endosonic group comprised agitation at power setting at 5 for 20 s.

Following the agitation protocol, canals were dried using paper points and each specimen was cut into three 1 mm thick slabs at 2, 4, and 6 mm from the apex. Approximately 40 μm thick ground sections were prepared by grinding with wet silicon carbide paper. A fluorescence light microscope at ×100 with a wavelength of 540–570 nm was used to examine the slides [Figure 1]. The slides were scored to assess the penetration of the irrigant solution into the dentinal tubules. According to the set criteria,[14] specimens with no visible alizarin red staining were assigned score 0, specimens with minor traces of alizarin red were assigned a score of 1, specimens with traces of alizarin red along the entire length of intra-radicular surface were assigned score 2, while score 3 and 4 were assigned to specimens with penetration of alizarin red in <50% and >50% tubules, respectively.{Figure 1}

Statistical analysis was performed using Kruskal–Wallis analysis of variance followed by Mann–Whitney U-test to reveal differences among the groups.


The efficacy of different agitation protocols was assessed in terms of irrigant penetration in the dentinal tubules using alizarin red dye at 2, 4, and 6 mm [Table 1]. The statistical evaluation of intergroup difference showed that there was no statistically significant difference between control group and K-file group at 2, 4, and 6 mm, while EndoActivator and endosonic showed statistically significant difference as compared to control and K-file at 2, 4, and 6 mm. The difference between EndoActivator and endosonic was not significant at 6 mm level [Figure 2].{Figure 2}{Table 1}


A combination of mechanical instrumentation and chemical irrigation has been found to accomplish reduction of the bacterial counts in infected root canals. Factors such as volume of irrigant, time of application, and method of activation of irrigating solutions are important but no consensus exists on them.[15],[16] Technological advances in recent times have led to the development of newer agitation devices that depend on various mechanisms for irrigant delivery and agitation.[12],[14],[17] Agitation techniques have been broadly divided as manual and mechanical or machine assisted. Manual techniques include agitation with hand files or gutta-percha while mechanical methods use sonic and ultrasonic instruments.

In the present study, influence of various agitation techniques on depth of penetration of 5% NaOCl used as irrigant was assessed at 2, 4, and 6 mm from the apex by labeling it with alizarin red dye and tracing it fluorescence microscopy. Alizarin red is a fluorescent organic compound widely used for quantifying calcific deposition. The use of an irrigant in conjunction with ultrasonic vibration directly influences the cleaning efficacy of the canal space.[18] Mechanical agitation or fluid flow is more important determining factors in the ability of NaOCl to dissolve tissue than the initial percentage of available active chlorine.[19] This could reduce the time needed for the antimicrobial efficacy of the irrigating solution.

The results from the present study showed endosonic agitation to be the best at all the three levels, i.e., 2, 4, and 6 mm. Studies have shown that passive ultrasonic irrigation is more effective in removing remnants of pulp tissue, dentin debris, and planktonic bacteria.[20],[21] Hydrodynamic activation improves penetration, circulation, and flow of the irrigant into the inaccessible regions of the root canal system. Although ultrasonic energy generates higher frequencies than sonic devices, both techniques may clean the canal system to a similar degree when sonic irrigation is applied for a longer time.[12]

The present study examined dye penetration into dentinal tubules followed by smear removal, and therefore, it is imperative that the ultrasonic agitation techniques produced better results. Further studies with larger sample size should be conducted to determine the optimal concentration of NaOCl to kill microorganisms without extracting collagen from dentin and the effect of different agitation techniques on the “debris score.”


Within the limitations of the present study, it can be concluded that ultrasonic agitation increases penetration of endodontic irrigant into dentinal tubules.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


1Siqueira JF Jr., Rôças IN. Clinical implications and microbiology of bacterial persistence after treatment procedures. J Endod 2008;34:1291-301.e3.
2Vertucci FJ. Root canal morphology and its relationship to endodontic procedures. Endod Topics 2005;10:3-29.
3Srivastava S, Kharbanda S, Jain A, Chhabra H, Singh A. Endodontic management of mandibular first molar with seven root canals using dental CT scan as a diagnostic aid: A rare case report. Endodontology 2015;27:184-7.
4Peters OA. Current challenges and concepts in the preparation of root canal systems: A review. J Endod 2004;30:559-67.
5Peters OA, Schönenberger K, Laib A. Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography. Int Endod J 2001;34:221-30.
6Harrison JW. Irrigation of the root canal system. Dent Clin North Am 1984;28:797-808.
7Spratt DA, Pratten J, Wilson M, Gulabivala K. Anin vitro evaluation of the antimicrobial efficacy of irrigants on biofilms of root canal isolates. Int Endod J 2001;34:300-7.
8Dunavant TR, Regan JD, Glickman GN, Solomon ES, Honeyman AL. Comparative evaluation of endodontic irrigants against Enterococcus faecalis biofilms. J Endod 2006;32:527-31.
9Zehnder M. Root canal irrigants. J Endod 2006;32:389-98.
10Naenni N, Thoma K, Zehnder M. Soft tissue dissolution capacity of currently used and potential endodontic irrigants. J Endod 2004;30:785-7.
11Haapasalo M, Shen Y, Qian W, Gao Y. Irrigation in endodontics. Dent Clin North Am 2010;54:291-312.
12Gu LS, Kim JR, Ling J, Choi KK, Pashley DH, Tay FR. Review of contemporary irrigant agitation techniques and devices. J Endod 2009;35:791-804.
13Huang TY, Gulabivala K, Ng YL. A bio-molecular film ex-vivo model to evaluate the influence of canal dimensions and irrigation variables on the efficacy of irrigation. Int Endod J 2008;41:60-71.
14Paragliola R, Franco V, Fabiani C, Mazzoni A, Nato F, Tay FR, et al. Final rinse optimization: Influence of different agitation protocols. J Endod 2010;36:282-5.
15Teixeira CS, Felippe MC, Felippe WT. The effect of application time of EDTA and NaOCl on intracanal smear layer removal: An SEM analysis. Int Endod J 2005;38:285-90.
16Jensen SA, Walker TL, Hutter JW, Nicoll BK. Comparison of the cleaning efficacy of passive sonic activation and passive ultrasonic activation after hand instrumentation in molar root canals. J Endod 1999;25:735-8.
17Walmsley AD. Ultrasound and root canal treatment: The need for scientific evaluation. Int Endod J 1987;20:105-11.
18Baumgartner JC, Cuenin PR. Efficacy of several concentrations of sodium hypochlorite for root canal irrigation. J Endod 1992;18:605-12.
19Moorer WR, Wesselink PR. Factors promoting the tissue dissolving capability of sodium hypochlorite. Int Endod J 1982;15:187-96.
20Van der Sluis LW, Versluis M, Wu MK, Wesselink PR. Passive ultrasonic irrigation of the root canal: A review of the literature. Int Endod J 2007;40:415-26.
21Weller RN, Brady JM, Bernier WE. Efficacy of ultrasonic cleaning. J Endod 1980;6:740-3.