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ORIGINAL ARTICLE Table of Contents  
Ahead of print publication
“Efficiency of removal of debris from root canal system with help of different irrigation system:” An in vitro scanning electron microscope study

1 Department of Conservative Dentistry and Endodontics, Narsinhbhai Patel Dental College & Hospital, Visnagar, Gujarat, India
2 Department of Pedodontics and Preventive Dentistry, Bapuji Dental College & Hospital, Davangere, Karnataka, India
3 Department of Conservative Dentistry and Endodontics, AMC Dental College and Hospital, Ahmedabad, Gujarat, India

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Date of Submission12-Nov-2019
Date of Acceptance13-Nov-2019
Date of Web Publication22-Nov-2019


Aims and Objectives: The aim of this study was to determine the efficiency of EndoActivator, passive ultrasonic irrigation, side-vented needle, and syringe irrigation for removal of dentinal debris (smear layer) in root canals prepared with same master apical file sizes. Materials and Methods: Forty mandibular premolars with mature apices (extracted) were selected for this study. Each tooth was decoronated 2mm coronal to the cementoenamel junction with a diamond disk to facilitate straight-line access for instrumentation. Apical patency was determined by inserting an ISO # 08 K-file. Working length was determined by placing a size 15 K-file into the canal until it appeared at the apical foramen; this length was measured and the working length was set at 1mm short of this measurement. The roots were sealed with yellow sticky wax (DPI) to avoid apical extrusion during irrigation. The root canals were prepared to size 40, 0.02 taper, using step-back technique. After each instrument change, manual irrigation was performed with 2-mL NaOCl (3%) using a 26-gauge syringe. Then, a total of 40 samples were randomly distributed into four groups. According to group, root canals were irrigated with EndoActivator, passive ultrasonic irrigation, side-vented needle, and syringe irrigation. The roots were spilt and sent laboratory for examination under scanning electron microscope. Results: Ultrasonic irrigation had highest removal of the smear layer than the other irrigation systems followed by EndoActivator, side-vented needle, and syringe irrigation. Conclusion: Ultrasonic irrigation resulted in better removal of the smear layer in the apical third of root canals than EndoActivator, side-vented needle, and conventional needle irrigation.

Keywords: EndoActivator irrigation, passive ultrasonic irrigation, side-vented needle irrigation, smear layer

How to cite this URL:
Patel NA, Vachhani KA, Khan MM, Gupta A, Pachore PJ, Bharatiya R. “Efficiency of removal of debris from root canal system with help of different irrigation system:” An in vitro scanning electron microscope study. Int J Oral Care Res [Epub ahead of print] [cited 2023 Mar 28]. Available from: https://www.ijocr.org/preprintarticle.asp?id=271461

  Introduction Top

Root canal treatment can be summarized as a series of procedures for cleaning, shaping, and obturation of root canal system. Chemomechanical preparation is one of the most important aspects of root canal treatment. Irrigation helps instruments to facilitate removal of debris, bacterial, and therapeutic material from root canal and uninstrumented areas such as isthmus, oval extension, and apical deltas.[1],[2]

Two important pillars of irrigation are tissue-dissolving ability and mechanical flushing action of irrigants. Walker reported sodium hypochloride (NaOCl) as root canal irrigant in 1936 and since then it has widely been accepted because of its antibacterial property and organic tissue-dissolving ability.[2],[3]

Conventional manual irrigation with a syringe and needle is widely accepted. Its flushing action depends on factors like diameter of needle, insertion depth, size and taper at prepared root canal hinder the exchange of irrigant and affect the debridement efficacy of irrigant. Different irrigant delivery devices increase the flow and distribution of irrigant within root canal system.[4],[5]

Acoustic streaming results from transmission of the energy at a freely oscillating file to the irrigant in the root canal during passive ultrasonic irrigation (PUI). It removes dentin debris and organic tissue from inaccessible areas of root canal.[1] EndoActivator (Dentsply Maillefer, Ballaigues, Switzerland) represents the sonic system with high-amplitude but low-frequency vibration. Mechanical oscillation produced at the tip at EndoActivator facilitates the removal of smear layer.[6]

Thus, to choose between different systems we must understand about the debris removal efficacy of different system. Thus, the purpose of this study was to compare the efficacy of EndoActivator, PUI, side-vented needle, and conventional syringe irrigation in removal of smear layer from root canal.

The null hypothesis stated that there was no significant difference in debris removal from root canals of teeth with the aforementioned irrigating systems.

  Materials and Methods Top

It is an in vitro scanning electron microscope (SEM) thesis study carried out at Department of Conservative Dentistry and Endodontics, Narsinhbhai Patel Dental College and Hospital, Visnagar, Gujarat, India, which was completed in a period of 3 months.

Forty freshly extracted mandibular premolars were selected for this study. All the teeth were thoroughly cleaned with an ultrasonic scaler and stored in 10% neutral buffered formalin solution for <1 week at room temperature as this will aid in disinfection of freshly extracted teeth and it will not alter the cutting characteristics of teeth.[7],[8]

All the teeth selected had matured root apices, extracted on periodontal and orthodontic ground, no caries, no restoration, and no previous endodontic treatment. All the teeth were decoronated 1mm above the cementoenamel junction (CEJ). The sectioned surfaces were flattened and smoothened with 2-mm grit abrasive paper.

Specimen preparation

The roots were endodontically instrumented 1 mm short of the apex with the step-back technique using K-file (Dentsply Maillefer) up to apical size ISO 40 after each instrument change, manual irrigation was performedNaOCl solution.

Experimental group distribution

After completion of preparation, samples were randomly assigned to experimental groups (n = 10) [Table 1].
Table 1: Experimental group distribution for the study

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All the samples were finally irrigated with 3mL of normal saline with a 26-gauge conventional needle and dried with absorbent paper points.

Sectioning of the sample

Deep grooves were made on the buccal and lingual surface of the root with diamond disks without perforating the canal. The roots were then split longitudinally using a chisel. One half of each root was selected for examination under SEM (Leo S–440i with Oxford energy dispersive X-ray analyzer [EDX] model 7060 with magnification from ×30 to ×3000000).

Scanning electron microscope evaluation

The specimens were examined under SEM under the magnification of ×2000, ×5000, and ×10000. The dentinal wall of apical third was observed for the presence or absence of smear layer and visualization of entrance to the dentinal tubules. Photomicrographs of the canal walls were taken at 2mm from apical foramen of each specimen and were evaluated individually by two previously calibrated examiners who were blind to irrigation regimen and attributed scores according to the rating system developed by Torabinejad et al.:[9]

  • 0 = no smear layer, no smear layer on the root canal surface with all the tubule clean and open.

  • 1 = moderate smear layer, outline of dentinal tubule visible or partially filled with debris.

  • 2 = heavy smear layer, smear layer covers the root canal surface and the tubules.

  Results Top

The result of this study is noted in [Table 2].
Table 2: Score of smear layer removal observed

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The data were analyzed through the chi-squared test, which was applied to compare one group with another group and analysis of variance test was used to compare one group with rest all the groups, and from the observations of this study, following results were obtained:

The surfaces of root canals and the dentinal tubules in the apical thirds of samples in Groups A and B were relatively free of smear layer but there was mild smear layer in the apical thirds of the root canal surfaces in samples of Group A. There was no statistically significant difference between Groups A and B; however, the mean value for Group B was the lowest among all the smear layers than the other irrigation systems. The surfaces of root canals and the dentinal tubules in the apical thirds of samples in Groups C and D were with heavy smear layer.

  Discussion Top

The smear layer on the surface of instrumented root canal was described by McComb and Smith.[10] They suggested that the smear layer comprised dentin debris, the remnant of odontoblastic process, pulp tissue, and bacteria.[10]

The smear layer thickness was generally 1–2 µm according to Mader et al.[11] It comprises two parts: superficial smear layer and material packed into dentinal tubules up to depth of 40 µm.[11]

Huang et al.[12] stated that there is a statistically significant difference in removal of smear layer from coronal third and middle third by step-back technique and crown-down technique but no difference in apical region of root. Therefore, in this study root canals were prepared to size 40.2% taper using step-back technique. According to Ram,[13] canals need to be enlarged to size 40 for penetration of irrigant to apical third of root canal.

PUI works by transmission of acoustic energy from an oscillating file or smooth wire to an irrigant in the root canal. Transmission of this energy occurs by means of ultrasonic waves and it induces acoustic streaming and cavitation of the irrigant. A file should oscillate freely in prepared root canal to meet the principle of PUI. Therefore, file size 20 was used for PUI of root canal.[14]

Baumgartner and Cuenin[15] reported that NaOCl in concentration of 5.25%, 2.5%, and 1% efficiently removes predentin and pulpal remnants from the uninstrumented surfaces. Hence, 3% NaOCl was used as irrigant in this study. EndoActivator uses sonic energy for irrigation of the root canal. It is somewhat different from PUI because it operates at a lower frequency of 1–6 KHz as compared to ultrasonic (25–30 KHz).[16]

Stamos et al.[17] stated that PUI removed more dentin smear layer from the root canal than sonic irrigation. In a study by Sabins et al.,[18] passive activation of endodontic files for irrigation with sonic or ultrasonic energy in canals for as little as 30s after hand instrumentation produced canals with significantly less smear layer.

Extrusion of solution is prevented beyond apex with side-vented needle as it is with closed end. In a side-vented needle, irrigant is extruded beyond 1–1.5mm of a side-vented needle could have generated a liquid film along the air bubble–canal wall interface. Fluid stagnation in this “Deadwater zone” failed to provide adequate irrigant replacement resulting in gross debris retention. Therefore, more debris could be defected from all parts of canal walls. Hence, side-vented needle is less effective in removal of smear layer.[19]

The findings of this study are consistent with the findings of a number of other studies.[6],[20]

  Conclusion Top

Ultrasonic irrigation resulted in better removal of the smear layer in the apical third of root canals than EndoActivator, side-vented needle, and conventional needle irrigation.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Lee SJ, Wu MK, Wesselink PR. The effectiveness of syringe irrigation and ultrasonics to remove debris from simulated irregularities within prepared root canal walls. Int Endod J 2004;37:672-8.  Back to cited text no. 1
Peters OA. Current challenges and concepts in the preparation of root canal systems: A review. J Endod 2004;30:559-67.  Back to cited text no. 2
Vianna ME, Gomes BP, Berber VB, Zaia AA, Ferraz CC, de Souza-Filho FJ. In vitro evaluation of the antimicrobial activity of chlorhexidine and sodium hypochlorite. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;97:79-84.  Back to cited text no. 3
Boutsioukis C, Gogos C, Verhaagen B, Versluis M, Kastrinakis E, Van der Sluis LW. The effect of apical preparation size on irrigant flow in root canals evaluated using an unsteady computational fluid dynamics model. Int Endod J 2010;43:874-81.  Back to cited text no. 4
Heard F, Walton RE. Scanning electron microscope study comparing four root canal preparation techniques in small curved canals. Int Endod J 1997;30:323-31.  Back to cited text no. 5
Luciana Margin BG, Guilberme Henrique RM, Manoel Eduarto de LM. Qualitative analysis of the removal of the smear layer in the apical third of curved roots: Conventional irrigation versus activation systems. J Endod 2011;37:1268-71.  Back to cited text no. 6
Kumar M, Sequeira PS, Peter S, Bhat GK. Sterilisation of extracted human teeth for educational use. Indian J Med Microbiol 2005;23:256-8.  Back to cited text no. 7
[PUBMED]  [Full text]  
Shaffer SE, Barkmeier WW, Gwinnett AJ. Effect of disinfection/sterilization on in vitro enamel bonding. J Dent Educ 1985;49:658-9.  Back to cited text no. 8
Torabinejad M, Khademi AA, Babagoli J, Cho Y, Johnson WB, Bozhilov K, et al. A new solution for the removal of the smear layer. J Endod 2003;29:170-5.  Back to cited text no. 9
McComb D, Smith DC. A preliminary scanning electron microscopic study of root canals after endodontic procedures. J Endod 1975;1:238-42.  Back to cited text no. 10
Mader CL, Baumgartner JC, Peters DD. Scanning electron microscopic investigation of the smeared layer on root canal walls. J Endod 1984;10:477-83.  Back to cited text no. 11
Qi Ling H, Xiu Qin Z, Guo Zhen D, Shi Guang H. SEM evaluation of canal cleanliness following use of Protaper Hand-Rotary instruments and stainless steel K-File. Chin J Dent Res 2009;12:45-9.  Back to cited text no. 12
Ram Z. Effectiveness of root canal irrigation. Oral Surg Oral Med Oral Pathol 1977;44:306-12.  Back to cited text no. 13
van 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.  Back to cited text no. 14
Baumgartner JC, Cuenin PR. Efficacy of several concentrations of sodium hypochlorite for root canal irrigation. J Endod 1992;18:605-12.  Back to cited text no. 15
Tronstad L, Barnett F, Schwartzben L, Frasca P. Effectiveness and safety of a sonic vibratory endodontic instrument. Endod Dent Traumatol 1985;1:69-76.  Back to cited text no. 16
Stamos DE, Sadeghi EM, Haasch GC, Gerstein H. An in vitro comparison study to quantitate the debridement ability of hand, sonic, and ultrasonic instrumentation. J Endod 1987;13:434-40.  Back to cited text no. 17
Sabins RA, Johnson JD, Hellstein JW. A comparison of the cleaning efficacy of short-term sonic and ultrasonic passive irrigation after hand instrumentation in molar root canals. J Endod 2003;29:674-8.  Back to cited text no. 18
Jensen 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.  Back to cited text no. 19
Jerome JC, Louis AJ, Richard MM. A scanning electron microscope study comparing the efficacy of hand instrumentation with ultrasonic instrumentation of the root canal. J Endod 1983;9: 327-31.  Back to cited text no. 20

Correspondence Address:
Nikunj A Patel,
Department of Conservative Dentistry and Endodontics, Narsinhbhai Patel Dental College & Hospital, S. P. Sahakar Vidyadham, Ambaji Gandhinagar Link Road, Near Kamana Char Rasta, Visnagar 384315, Gujarat.
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/INJO.INJO_38_19


  [Table 1], [Table 2]


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