Indian Journal of Dental Research

: 2011  |  Volume : 22  |  Issue : 5  |  Page : 659--663

Root canal debris removal using different irrigating needles: An SEM study

Sheetal Ghivari, Girish Kubasad 
 Department of Conservative Dentistry and Endodontics, Sharad Pawar Dental College, Swangi (Meghe), Wardha, India

Correspondence Address:
Sheetal Ghivari
Department of Conservative Dentistry and Endodontics, Sharad Pawar Dental College, Swangi (Meghe), Wardha


Aim: This study was carried out to compare the efficacy of three irrigating needle designs in removal of debris from different parts of the root canal. Materials and Methods: Thirty human maxillary canines were prepared using HERO Shaper rotary system and irrigated with 1 ml of 5.25% sodium hypochlorite (NaOCl) after each instrument change. Three 25-gauge irrigation needle designs - brush-covered Navi Tip FX (Group I), side-vented needle RC Twents (Group II) and single-beveled (Group III) irrigating needles - were tested for their efficiency in debris removal in three different parts of the root canal (n=10 canals per group). Following instrumentation, the roots were vertically sectioned and divided into coronal, middle and apical thirds for observation under scanning electron microscope (×200 magnification). Debris on the canal wall was evaluated by using a four-scale scoring system described by Paque and his co-workers. Results: The canals irrigated with brush-covered needle Navi Tip FX (Group I) showed lower average debris score, indicating greater removal of debris in coronal third as compared to middle and apical thirds, whereas the canals irrigated with side-vented needle (Group II) and single-beveled needle (Group III) exhibited lower average score in the middle third than coronal and apical thirds. All the three needle designs exhibited higher debris score in apical third of the root canal. Tukey multiple comparisons test was applied at a significance level of P>0.05. A statistically significant difference (P<0.05) was observed in the debris removal in the coronal and middle thirds of root canals irrigated with brush-covered Navi Tip FX (Group I) and side-vented (Group II) needles, respectively, when compared with other needle design groups. Conclusion: Within the limitations of this study, it can be concluded that all the needle designs tested were effective in certain regions of the root canal with apical third uncleaned. Side-vented needle by creating turbulence removed debris effectively in coronal and middle thirds.

How to cite this article:
Ghivari S, Kubasad G. Root canal debris removal using different irrigating needles: An SEM study.Indian J Dent Res 2011;22:659-663

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Ghivari S, Kubasad G. Root canal debris removal using different irrigating needles: An SEM study. Indian J Dent Res [serial online] 2011 [cited 2022 Jan 25 ];22:659-663
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Success of endodontic treatment is determined by removal of pulpal remnants, dentinal filings and microbes from the root canal system. Current instrumentation techniques are ineffective in shaping all surfaces and irregularities within the canal system. [1] Additionally, instrumentation produces a 1-5 mm thick smear layer that blocks the dentinal tubules from irrigant and sealer penetration. [2] Tissue debris and smear layer that remain after mechanical instrumentation can harbor microorganisms and disrupt the seal between the material and canal wall, leading to treatment failure. [3] Therefore, chemical debridement via use of irrigant is a necessary adjunct to mechanical instrumentation to remove organic and inorganic debris created during instrumentation.

Because of its potent ability to kill microorganisms and to dissolve organic debris, 5.25% sodium hypochlorite (NaOCl) is a popular irrigant to use during instrumentation and as a final rinse. [4] Both irrigant volume and fluid flow dynamics are important factors that affect canal debridement. [5] However, traditional needle irrigation delivers solutions no further than 1 mm past the tip of the needle and is relatively ineffective in cleaning apical third of canal walls. [6]

An improved delivery system is highly desirable for effective root canal debridement. Such system should have adequate flow of irrigant to working length without forcing the solution into periapical tissues. [7]

Numerous investigations have been performed to evaluate the effectiveness of instruments and instrumentation techniques, and irrigants and methods of irrigation in canal debridement. These studies have all demonstrated that debris remains in the root canal system after instrumentation and irrigation. [8],[9],[10]

The aim of this study was to examine the canal debridement efficacy in different parts of instrumented root canal irrigated with brush-covered (Navi Tip FX), side-vented (RC Twents) and single-beveled needles.

 Materials and Methods

Thirty freshly extracted maxillary canines with completely formed apices were selected and stored in 0.9% saline solution. The teeth were radiographed in mesiodistal aspect to confirm canal patency, presence of single canal and complete root formation. Root canals with abnormal anatomy and calcifications were excluded. The teeth were decoronated to expose pulp chamber at a constant length of 16 mm from decoronated surface to root apex. The file was inserted into the canal until the tip just visible at the apical foramen, and from this length, 1 mm was subtracted to determine the actual working length.

The teeth were then randomly divided into three groups of 10 teeth each. All teeth were instrumented with HERO shapers rotary nickle titanium system. Group I consisted of teeth irrigated with brush-covered needle (Navi Tip FX, Ultradent, south jordan, UT, USA). In Group II, the teeth were irrigated with side-vented needle (RC Twents, Prime Dental Products, Mumbai, India) and in Group III, the teeth were irrigated with single-beveled needle (Prime Dental Products, Mumbai, India). The 25-gauge needle size was selected for all the needle designs.

The root canal was flooded with 5.25% NaOCl and replenished with 1 ml after each instrument change. The rubber stopper was placed on the needle and the needle was advanced into the root canal 3 mm short of the working length. After the coronal enlargement with Endoflare file (HERO shapers), initial glide path was achieved using K-files of size #15 and #20 to the working length. Canals were instrumented to size #30, with 0.04 taper first and then 0.06 taper using crown-down approach with HERO shaper nickel-titanium instruments (Micro-Mega, Besancon, France). Rotary files were used in controlled slow-speed, high-torque motor, with a speed of 250 rpm. After each instrument change, canal was flooded with 1 ml of 5.25% NaOCl using the needle type designated for each group. Irrigant was delivered at an average rate of 5 ml per root canal. At the end of instrumentation, each canal was flushed with 1 ml of 5.25% NaOCl.

Immediately after completion of root canal preparations, the samples were coded to allow for blinded evaluation of the samples. The canals were dried with paper points. Teeth were carefully grooved vertically with carborundum disk on the buccal and lingual surfaces without penetrating the root canal. The teeth were then cleaned and dried before splitting them into two halves with chisel and mallet. The root canal half with the most visible part of apex was used for the evaluation under scanning electron microscope (SEM). Each half of tooth was divided into three equal parts designated as coronal, middle and apical thirds. The samples were air-dried, sputter-coated with platinum using fine-coat ion sputter (Fine coat ion sputter JFC-1100, JEOL Ltd., Tokyo, Japan) and then observed under SEM with ×200 magnification.

The area to be examined was standardized for each sample. The central beam of the SEM was directed to the center of each third of the root canal by the SEM operator under ×30 magnifications, and then the magnification was increased to ×200 and the area of the canal wall captured on the screen of the SEM was used for scoring the sample.

Debris on the canal wall was evaluated using four-level scoring systems as described by Paque and his co-workers: [11]

Score 1: Clean root canal, only few small debris particles.

Score 2: Few small islets of debris covering less than 25% of the root canal wall.

Score 3: Many accumulations of debris covering more than 25%, but less than 50% of the root canal wall.

Score 4: More than 50% of the root canal wall covered by debris.

Two calibrated and blinded evaluators independently scored the samples. The scores were then compared and if a difference was found, the two evaluators jointly examined the sample with a different score. If they could not reach an agreement, a third evaluator helped in scoring. The code was then broken and each sample was assigned to its experimental group. The results were statistically analyzed using the Tukey multiple comparisons test at a significance level P<0.05.

To estimate intra-observer and inter-observer reproducibility, 20 micrographs were assessed three times in random order by two observers.


The mean scores and their comparison in apical, middle, and coronal thirds of Groups I, II and III are shown in [Table 1]. The representative SEM images (Groups I, II and III) of coronal, middle and apical thirds are shown in respective micrographs [Figure 1],[Figure 2],[Figure 3],[Figure 4],[Figure 5],[Figure 6],[Figure 7],[Figure 8] and [Figure 9].{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}{Figure 7}{Figure 8}{Figure 9}{Table 1}

The canals irrigated with brush-covered needle Navi Tip FX (Group I) showed lower average debris score in coronal third [Figure 1] when compared to middle [Figure 2] and apical thirds [Figure 3], whereas the canals irrigated with side-vented needle (Group II) exhibited greater removal of debris with lower average score in the middle third [Figure 5] than coronal [Figure 4] and apical thirds [Figure 6]. Root canals irrigated with single-beveled needle showed less removal of debris, with higher debris score in all the parts of root canal [Figure 7],[Figure 8] and [Figure 9]. All the three needle designs exhibited higher debris score in apical third of the root canal.

The debris removal in the coronal third of root canals irrigated with brush-covered needle (Group I) showed a statistically significant difference (P<0.05) when compared with debris removal by side-vented and single-beveled needles, and no statistically significant difference (P>0.05) in debris removal was observed in coronal third when canals were irrigated with side-vented and single-beveled needle designs.

However, the side-vented needle (Group II) showed statistically significant (P<0.05) removal of debris in middle third compared to brush-covered and single-beveled needles.

The single-beveled needle (Group III) showed more debris score in all the three parts of root canal compared to Groups I and II, indicating its inadequacy in removal of debris.

The difference in debris removal from apical third when compared between the groups was not statistically significant (P>0.05) as evident in Tukey multiple comparison test.


One of the most important objectives during root canal instrumentation is the removal of pulp tissue, elimination of microorganisms and their toxins from the root canal system. The ability to achieve this objective was evaluated in the present study by root canal irrigation using brush-covered, side-vented and single-beveled needles.

The cleaner coronal third of the root canal irrigated with brush-covered needle (Navi Tip FX) is correlated to the presence of brush with small nylon bristles attached to apical 5 mm of needle which worked similar to a bottle brush, removing the debris from coronal portion of root canal efficiently. [8] Better debris removal was observed in middle third of root canal irrigated with side-vented (RC Twents) needle compared to the coronal and apical thirds. As the side-vented (RC Twents) needles have closed end with lumen 2 mm from their end on lateral surface, turbulence is created around the end of the needle which enables better removal of debris in middle third. [10]

Significant amount of debris was left behind throughout the canal wall in coronal, middle and apical thirds in the root canal irrigated with single-beveled needle. The presence of single bevel has expressed fluid in one direction, preventing outward movement of debris. [12]

The amount of debris was evaluated utilizing ×200 magnification to view wider area of root canal wall on SEM. [8],[13]

The results obtained in this study might have been improved if the brush-covered needle was mechanically activated in an active scrubbing action during the irrigation process to increase the efficiency of the brush.

The complete debridement of root canal during endodontic therapy depends upon the diameter of the needle, position of the irrigating needle within root canal, final size of enlarged root canal, viscosity of irrigant, velocity of irrigant at the tip of needle and orientation of the bevel of the needle. [12]

In the present study, the 25-gauge needle was inserted within the root canal 3 mm short of the working length which is prepared to master apical preparation size 30. The presence of bristles on the brush-covered needle poses obstruction for insertion of needle to the working length and also there is increased risk of irrigant extrusion toward the periapical tissues. Apical preparation size 30 with taper of 0.06% was sufficient to allow sufficient flow of irrigant within the root canal. [14],[15]

Furthermore, studies should be motivated to address debridement efficacy of irrigant in apical third of root canal by varying the depth of insertion of the needle and taper within the root canal.


Within the limitations of this study, all the needle designs tested left the debris on the canal wall. The brush-covered needle was effective in coronal third, while side-vented needle in the middle third and single-beveled needle failed to remove debris from any part of root canal.


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