|Year : 2016 | Volume
| Issue : 1 | Page : 2-6
Comparative evaluation of the efficacy of three different irrigation devices in removal of debris from isthmus: An in vitro study
Aparna Birajdar, Sucheta Sathe, Manisha Dixit, Srilatha Shanmugasundaram
Department of Conservative Dentistry and Endodontics, M.A. Rangoonwala College of Dental Sciences and Research Centre, Pune, Maharashtra, India
|Date of Web Publication||21-Jun-2016|
Department of Conservative Dentistry and Endodontics, M.A. Rangoonwala College of Dental Sciences and Research Centre, Azam Campus, Pune - 411 001, Maharashtra
Source of Support: None, Conflict of Interest: None
Aim: To evaluate the cleaning efficacy of endoactivator, EndoVac (EV), and self-adjusting file (SAF) as irrigant adjunct in the removal of debris from isthmus.
Materials and Methods: Forty extracted human mandibular molars were taken. Canals were prepared up to F4 protaper file. Irrigation after each file size was done by 1 ml normal saline. Final irrigation was done by 4 ml of 5% NaOCl and activated in each canal for 1 min with different activating systems. Teeth were divided randomly into 4 groups according to activation system as manual activation (control group, n = 10), Group 2 SAF system (n = 10), Group 3 endoactivator (n = 10), and Group 4 EV (n = 10). After activation final flush was done with 1 ml saline. The mesial root of each tooth was sectioned and checked for isthmus cleanliness by stereomicroscopic analysis. Images were analyzed by ImageJ software. Percentage of debris remaining in each group was calculated.
Results: There is no statistically significant difference in cleaning efficacy of endoactivator, EV, and SAF systems.
Conclusion: All three techniques remove debris from isthmus area more efficiently than manual dynamic activation.
Keywords: Endoactivator; EndoVac; isthmus; self-adjusting file.
|How to cite this article:|
Birajdar A, Sathe S, Dixit M, Shanmugasundaram S. Comparative evaluation of the efficacy of three different irrigation devices in removal of debris from isthmus: An in vitro study. Endodontology 2016;28:2-6
|How to cite this URL:|
Birajdar A, Sathe S, Dixit M, Shanmugasundaram S. Comparative evaluation of the efficacy of three different irrigation devices in removal of debris from isthmus: An in vitro study. Endodontology [serial online] 2016 [cited 2019 Mar 26];28:2-6. Available from: http://www.endodontologyonweb.org/text.asp?2016/28/1/2/184318
| Introduction|| |
Complete debridement of the root canal system is important for endodontic success. Smear layer produced due to shaping of root canals contains organic and inorganic substances, including fragments of odontoblastic processes, microorganisms, and necrotic materials.  If smear layer is not removed then it can harbor microorganisms and decrease the efficacy of the seal created by root filling materials, thus leading to treatment failure.  Therefore, irrigant agitation is a necessary adjunct to mechanical instrumentation as a method of chemical debridement to remove debris and bacteria from the entire canal system. 
It is difficult to flush debris effectively from the isthmi of roots containing multiple canals. Though isthmus area contains mainly soft tissue remnants and microbes associated with infected pulpal tissues since these areas remain uninstrumented. Eradication of this debris from isthmus area relies on the efficacy of irrigants. A hydraulic force produced by high flow rate of these irrigants can detach debris caught within the predentin collagen network of the uninstrumented isthmus canal walls. 
For efficient cleaning of root canal, irrigants should be in contact with the canal surface.  Traditional needle irrigation technique is insufficient for complete cleaning from complex anatomy of root canal system such as lateral canal, isthmuses, fins, and accessory canals. Because solutions delivered by these needle tips do not go beyond 0-1.1 mm. , To increase the flow and distribution of irrigating solutions at the apical third level of root canal, there are different devices available for irrigation delivery. 
Design of EndoActivator system is such that it safely and vigorously energize the hydrodynamic phenomenon. According to evidence-based endodontics, cavitation and acoustic streaming significantly improve debridement and the disruption of the smear layer and biofilm. Activation of irrigants promotes deep cleaning and disinfection into lateral canals, fins, webs, and anastomoses. This system consists of a portable handpiece and three types of disposable flexible polymer tips of different sizes that do not cut root dentin.
The EndoVac (EV) system (Discus Dental, Culver City, CA, USA) is based on apical negative pressure mechanism where it drains irrigants at the apical third level of the canal system and removes debris from it. When compared with needle irrigation, EV introduces higher flow of irrigant and produce better debridement at 1 mm from working length.  Moreover, it extrudes less irrigant so less risk of NaOCl incident.
The Self-Adjusting File system ([SAF]; ReDent-Nova, Ra'anana, Israel) has the ability to adapt to cross-section of the root canal and adapts itself three-dimensionally (3D) to the shape of the root canal. It is a hollow and flexible file which vibrates when operated and removes a uniform dentin layer from the root canal walls even in oval, flat root canals.  Besides shaping this, file allows for continuous irrigation of the root canal throughout the procedure, and additional irrigation activation due to vibrating motion.
At present, there are few studies available comparing the ability of the EV and endoactivator system to remove debris in complex canal systems with isthmus connections. Therefore, the purpose of this study was to compare the effectiveness of debris removal from isthmus between the SAF system, endoactivator, and EV system in the mesial root of mandibular molars.
| Materials and Methods|| |
Forty extracted human mandibular molars were selected. Patency of the root canals was obtained using a 10 K-file. Mesial roots of each molar were prepared till size F4 protaper. After each instrumentation, 1 mL of normal saline was used as irrigant. Then, teeth were randomly divided into four groups as per different activating systems where each group contains ten samples each. About 5.2% sodium hypochlorite was used for irrigation activation.
Hence, Group 1 was for manual dynamic activation which is a control group. In this group, irrigant was activated with the help of master cone gutta-percha (GP) point. Irrigant is introduced in the canal with 27 gauge needle. The GP cone is used for short, gentle strokes to hydrodynamically displace and agitate an irrigant. The irrigant was activated in the canal for 1 min.
In Group 2, irrigant was introduced in the canal with 27 gauge needle and then activated in the canal with the help of endoactivator. Endoactivator was set at 10,000 cpm with a 35/0.04 (blue) tip, inserted 2 mm short of the working length, and activated for 1 min.
In Group 3, activation of irrigation was done with EV system. The macro-cannulus used to irrigate canal for 30 s with 5.25% NaOCl, then micro-cannulus inserted to full working length. After all, instrumentation is complete; the MacroCannula is used to remove coarse debris inside the canal.
Group 4 is SAF system (ReDent-Nova), where SAF itself is used for irrigation activation. It is a hollow file which allows continuous irrigation used with in-and-out vibrating motion. A silicone tube was attached at the shaft of the file through which irrigation was performed. The irrigant flows through the lattice wall of the canal and backflow coronally. There was no positive pressure generated in the root canal. The irrigation was performed continuously during the procedure using a special irrigation apparatus (VATEA irrigation device). This apparatus contained two separate irrigation fluid reservoirs which were attached to the hollow SAF file via a dual silicone tube that allowed each irrigant to be separated from the other until the delivery point.
After activation with different techniques, final rinse was done with 1 ml of normal saline. Distal roots were then separated; mesial roots were sectioned longitudinally 4 mm from apex. Isthmus cleanliness was checked with stereomicroscope (XTL 3400E, Magnification, Wuzhou New Found Instrument Co. Ltd., China). Images were obtained with stereomicroscope at ×25 magnification. These images were analyzed under ImageJ software NIH (National Institutes of Health, Bethesda, Maryland, U.S.).
Statistical analysis was done with one-way ANOVA followed by Tukey's post hoc test.
| Results|| |
Stereomicroscopic images obtained are shown in [Figure 1],[Figure 2],[Figure 3]a nd [Figure 4] and [Table 1].
|Table 1: Mean percentage comparison of efficacy of three different irrigation devices with control group in removal of debris from isthmus|
Click here to view
The mean percentages of debris removal in isthmus area were highest in case of Group 4; i.e., SAF (4.46 ± 1.47) followed by Group 2; endoactivator (4.49 ± 2.94), Group 3; and EV (4.51 ± 1.66) as compared to control group (Group 1) i.e. 15.19 ± 3.89. There was statistically significant difference seen between all the groups using one-way ANOVA (P < 0.001).
However, when the comparison was done within groups using Tukey's post hoc test, only control group was found to be statistically significant with all other groups (P < 0.001), whereas no significant differences were found with all other group comparisons [Figure 5].
|Figure 5: Comparison of efficacy of three different irrigation devices with control group in removal of debris from isthmus|
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| Discussion|| |
In this study, four different irrigation/agitation techniques were selected for comparison of their isthmus debridement efficacy in the mesial root of mandibular molars. Endoactivator is sonic activation system while EV is based on apical negative pressure theory where the agitation/negative suction components are inserted to the working length of the instrumented canals. SAF uses vibratory motions to activate irrigant in the canal and it allows irrigant till the working length. Manual dynamic activation, which is a control group, where gentle strokes are used to hydrodynamically displace and agitate an irrigant.
For manual dynamic activation of irrigants, a well-fitting GP master cone is gently moved up and down in short 2- to 3-mm strokes within an instrumented canal. This process can produce an effective hydrodynamic effect and significantly improve the displacement and exchange of any given reagent. During pushing movements, there might be higher intracanal pressure generation which leads to more effective delivery of irrigant to the "untouched" canal surfaces. Other theory says that push-pull motion of GP point probably acts by physically displacing, folding and cutting of fluid under "viscously-dominated flow" in the root canal system. 
Endoactivator system has safe, noncutting polymer tips and easy-to-use subsonic handpiece to agitate irrigants in the canal. A cloud of debris can be observed within fluid-filled pulp chamber when endoacvtivator tip is used. The vibration of tip with up and down motion in short vertical strokes produces a powerful hydrodynamic phenomenon. For optimum debridement and disruption of smear layer and biofilm, 10,000 cpm can be used. 
EV is a true apical negative pressure system. It uses suction to PULL irrigant down the root canal, and then up and away into Hi-Vac suction unit. Hence, there is less apical extrusion of irrigant. EV applies suction instead of forceful injection so known as "negative apical pressure" and therefore apical extrusion is less. EV master delivery tip (MDT), i.e. MDT delivers irrigant, at same time MacroCannula removes coarse debris from the canal. MicroCannula is 28 gauge needle (0.32 mm) with 12 laser-drilled microscopic evacuation holes; each hole is <100 microns in size. These holes are placed at the end of the needle. This MicroCannula helps to draw fluid to apical termination through its holes thus creating a vortex-like cleaning of the apical third. Aspiration pressure is around −20 kPa. The irrigant is flows from coronal to apical third and then finally suctioned. 
Debris removal was much more difficult in the narrow isthmus regions than in the instrumented canals.  Since MicroCannula is of size 0.32 mm, canals were prepared till F4 protaper size. The previous study showed better debridement 1 mm from working length using EV system compared with needle irrigation.  Susin et al. in their study concluded that both techniques involve the placement of the agitation component directly to working length, the use of the ANP technique resulted in considerably cleaner isthmi when compared with manual dynamic irrigation. 
In this study, SAF proved not to be statistically different from the other systems in isthmus cleanliness. SAF is a new file system which adapts to canal 3D.  However, in this study, it was used postinstrumentaion only for irrigation agitation, which might have altered the expected results of the system.
The incidence of isthmus in mesial roots of mandibular first molar at 3-4 mm from apex is 80%, while for maxillary premolar at 1 mm from apex it is 16%. For the mesiobuccal root of maxillary first molar at 2-4 mm from apex incidence of isthmus is around 30-50%.  Hence, the high incidence of Type IV isthmus was found in the apical 5 mm of mesial roots of mandibular first molars. This may affect surgical as well as nonsurgical endodontic procedures.  Therefore, mandibular molars were selected for this study.
Gutarts in his study opined that it was difficult to use scanning electron microscopy for examining the apical 0.5-1 mm of the canal walls and suggested using light microscopy for critically examining the canal cleanliness (i.e., debris retention) at the different canal levels in the critical zone in which the apical lock phenomenon appeared to exist inside a closed canal (i.e. 0-2 mm from the apical seat).  Thus, stereomicroscope was employed in the study to examine the isthmus area at apical third. Light microscopy does not have the resolution of scanning electron microscopy to identify smear layer remnants from the instrumented canal walls. As smear layer is not present in the noninstrumented isthmus regions, no attempt was made in this study to examine the efficacy of smear layer removal.
| Conclusions|| |
Within the limitations of the study, it is concluded that there is no significant difference in cleaning efficacy of endoactivator, endovac, and SAF systems. These three techniques remove debris from isthmus more efficiently than manual dynamic activation.
I would like to thank Dr. Vivek Hegde for his guidance and help with endoactivator and also I'm greatful to Dr. Shail Jaggi for helping with endovac system.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]