Journal of Conservative Dentistry

ORIGINAL RESEARCH ARTICLE
Year
: 2018  |  Volume : 21  |  Issue : 2  |  Page : 216--220

Depth and percentage of resin-based sealer penetration inside the dentinal tubules using EndoVac, EndoActivator, Navi tip FX irrigation system: A confocal laser scanning microscope study


Ramesh Bharti1, Aseem Prakash Tikku1, Anil Chandra1, Vijay Kumar Shakya1, Simith Yadav2,  
1 Department of Conservative Dentistry and Endodontics, King George's Medical University, Lucknow, Uttar Pradesh, India
2 Department of Conservative Dentistry and Endodontics, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Correspondence Address:
Dr. Simith Yadav
Department of Conservative Dentistry and Endodontics, Postgraduate Institute of Medical Education and Research, Chandigarh
India

Abstract

Aim: This in vitro study was conducted to evaluate the effect of EndoVac, EndoActivator, and Navy Tip FX irrigation system on lateral depth and percentage of sealer penetration into the dentinal tubules using confocal laser scanning microscope. Materials and Methods: Forty recently extracted single-rooted mandibular premolars were taken and root canal treatment was performed using three different irrigation system, that is, EndoVac, EndoActivator, and Navi tip FX. The samples were divided into 4 groups according to the irrigation system used: Control or conventional needle (Group I), Navi Tip FX (Group II), EndoActivator (Group III), and EndoVac (Group IV). All teeth were obturated using AH Plus sealer labeled with fluorescent rhodamine B dye. The teeth were sectioned at coronal (5 mm), middle (3 mm), and apical 3rd (1 mm) from the apex. Total percentage and maximum depth of sealer penetration were measured using confocal laser scanning microscopy. The data were evaluated statistically using Kruskal–Wallis test with a 95% confidence level (P = 0.01). Results: EndoVac resulted in more sealer penetration then EndoActivator and Navi Tip FX irrigation system. Endoactivator resulted in more sealer penetration in comparison to Navi Tip FX. Conclusion: Percentage and depth of sealer penetration were more at apical and middle 3rd with Endovac system followed by Endoactivator and Navi tip FX system.



How to cite this article:
Bharti R, Tikku AP, Chandra A, Shakya VK, Yadav S. Depth and percentage of resin-based sealer penetration inside the dentinal tubules using EndoVac, EndoActivator, Navi tip FX irrigation system: A confocal laser scanning microscope study.J Conserv Dent 2018;21:216-220


How to cite this URL:
Bharti R, Tikku AP, Chandra A, Shakya VK, Yadav S. Depth and percentage of resin-based sealer penetration inside the dentinal tubules using EndoVac, EndoActivator, Navi tip FX irrigation system: A confocal laser scanning microscope study. J Conserv Dent [serial online] 2018 [cited 2019 Dec 7 ];21:216-220
Available from: http://www.jcd.org.in/text.asp?2018/21/2/216/228261


Full Text

 Introduction



Complete root canal disinfection is the mainstay of the endodontic treatment. Various options are available to endodontist as far as complete disinfection of root canal system is concerned. This includes biomechanical, chemomechanical techniques, and various irrigation devices which ensure complete removal of debris from the most complex part of root canal, especially apical third which includes many ramifications such as isthmuses, deltas, and lateral canals.[1] Sealer penetration inside the dentinal tubules might play a contributory role in preventing secondary infection. Degree and depth of sealer penetration depend on the extent of organic and inorganic debris being removed and this, in turn, depends on irrigation.[2] Studies done in the past have shown that by using conventional needle irrigation system, irrigant is not able to flow more than 1–2 mm beyond the needle tip.[3] Considering this as a major problem researchers came up with EndoActivator system. EndoActivator system is a mechanical agitation device that vibrates the fiber needle inside the root canal which creates acoustic streaming of the irrigant fluid and makes it flow to the deeper and inaccessible areas of the root canal. Effectiveness of EndoActivator in the apical third of the root canal is questionable because agitation does not significantly improve the flow of irrigant in the apical third area.[4] Excessive positive pressure with the conventional needle irrigation in the anticipation of reaching apical third again has a danger of periapical extrusion of the irrigant fluid, the consequences of which can be very dangerous. Hence, a new irrigation device based on negative pressure was introduced, namely, EndoVac system which has 3 components: (1) Master delivery tip, (2) macrocannula, and (3) microcannula. Microcannula reaches the apical third of the root canal, macrocannula removes debris from the middle third, and the major delivery tip constantly delivers irrigation solution into the pulp chamber and the negative pressure makes sure the debris and the force of action of the irrigant is always in the coronal direction and hence eliminating the chances of periapical extrusion.[5] Navi Tip FX is a 30-gauge brush-covered irrigation needle ((NaviTip FX; Ultradent Products Inc., South Jordan, UT, USA) having a flexible tip that can easily navigate the curved canals. The studies through scanning electron microscope (SEM) have shown cleaner coronal one-third of the instrumented root canal teeth following irrigation with Navi Tip FX.[6]

Completely dense obturation consisting of fluid-tight seal will eventually close all avenues of reentry of the microbes. Sometimes, even after a good biomechanical and chemomechanical preparation, the degree and depth of sealer penetration remain compromised, it is mainly because of the smear layer.

For complete removal of the smear layer, especially from the lateral canals and other ramifications present in the apical third, a good irrigation system is required.[7],[8] Role of irrigants is very important in removal of smear layer, as they can act on the organic and inorganic component of the smear layer and cause its disintegration accordingly.[9] For optimum irrigant action, irrigant delivery method is also equally important as the apical one-third is the main area that is not reached by conventional irrigation techniques.[3] Confocal laser scanning microscope (CLSM) used in the present study provided the advantage of observations being made in near normal conditions, and no special processing technique was required. Studies have shown that in comparison to SEM, CLSM has a less chances of producing artifacts.[10] It also allowed visualization of the resin–dentin adhesive interface using fluorescence, and the interpretation of CLSM data was directly related to the penetration of the fluorescently labeled AH Plus sealer. Hence, the aim of this study was to check the depth and percentage of resin-based sealer penetration into the dentinal tubules using EndoVac, EndoActivator, and Navy Tip FX irrigation system by CLSM.

 Materials and Methods



Sample selection and specimen preparation

Forty single-rooted mandibular premolars extracted for the orthodontic therapeutic purpose were randomly selected. Inclusion criteria for the present study included:

Teeth having single canal and without apical curvature more than 5° as determined by Schneider's method.[11]

Exclusion criteria

Teeth having more than one canal or dilacerations, radicular resorption, fracture, or an endodontic filling were excluded from the study.

Selected teeth were cleansed of extraneous debris and calculus using an ultrasonic scaler. After cleansing, specimen was rinsed under running tap water and stored in 0.2% sodium azide solution until use at 37°C.

They were decoronated at the cementoenamel junction and sectioned to a standardized length of 14 mm. Access opening was made with Endoaccess bur (Dentsply, Ballaigues, Switzerland) and pulp extirpated with barbed broach. The canals were accessed, and working length was determined by inserting a 21-mm, #10 K-file, until just visible at the apical foramen. After this, 1 mm was subtracted, and the resulting length became the working length. Instrumentation was performed using crown-down technique with ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) rotary nickel-titanium instruments. The canals were prepared following sequence from X1 (size 17, 0.04 taper), X2 (size 25, 0.06 taper), X3 (size 30, 0.07 taper) to apical size X4 (size 40, 0.06 taper) to working length. Between each instrument, the canal was irrigated with 5 mL 3% sodium hypochlorite (NaOCl) (Septodont Healthcare India Pvt., Ltd., batch number 17054) solution with a 27-gauge syringe. Apical patency was maintained by passing #15 K-file through the apical foramen between files. To eliminate smear layer to simulate clinical setting conditions, all canals were irrigated with 3 mL of 17% ethylenediaminetetracetic acid (EDTA) (Prevest Denpro Limited, Jammu, India, lot number 20) for 1 min, followed by 3 mL of 3% NaOCl. Finally, 3% NaOCl at 37°C was activated/delivered with different methods [Table 1]. A final rinse was performed using 5 mL of distilled water using 27-gauge side-vented needle to remove any remaining irrigating solution. The canals were dried with sterile absorbent paper points, and the apical foramen was sealed with wax to cover the apical 2 mm. The samples were randomly divided into 4 groups (n = 10), control group (Group I), and three experimental groups, that is, Navi Tip FX (Group II), EndoActivator (Group III), and EndoVac (Group IV). Each group composed of 10 teeth.{Table 1}

All specimens were obturated with gutta-percha coated with AH Plus sealer (Dentsply, Ballaigues, Switzerland). Sealer was mixed as per the manufacturer's recommendation on a mixing pad using a metal spatula. To view under CLSM, sealer was mixed with few grains of Rhodamine B dye. The maximum absorption of the dye is 540 nm, and the maximum emission is 625 nm. The rhodamine B dye–sealer mixture was placed along the entire length of the root canal with size 30 lentulo spirals, keeping the instrument 3 mm from the canal apices with the handpiece running at 300 rpm attached to a micromotor. Gutta-percha size 40, 0.06 taper cones were lightly coated with the Rhodamine B mixed sealer and placed to the entire working length as the master cone. The canals were obturated with cold lateral compaction technique using size 25 nickel-titanium finger spreaders (Dentsply Maillefer, Ballaigues, Switzerland) and size 20, 0.02 taper gutta-percha accessory cones. The teeth were sealed with an interim restorative material at coronal end and stored in an incubator at 37°C, 91% relative humidity for 48 h to allow complete setting of sealer material.

Each specimen was marked at coronal, middle, and apical third, that is, at 2, 4, and 8 mm from the apex and sectioned using a silicon carbide disc. Each section was then grinded to a uniform thickness of 3 mm using the same disc coronally and apically.

Sample evaluation using a confocal microscope

All specimens were mounted onto glass slides and examined with a Leica TCS-SPE confocal laser scanning microscopy (Leica, Mannheim, Germany). The method used by Gharib et al. was applied to evaluate the images.[12] First, each sample image was imported into Photoshop (Adobe Systems, Inc., San Jose, CA, USA). In each sample image, the circumference of the root canal wall was outlined and measured with a Photoshop measuring tool. Next, areas along the canal walls in which the sealer penetrated into dentinal tubules were outlined and measured using the same method. The outlined lengths where sealer had penetrated were divided by the canal circumferences to calculate the percentage of sealer penetration into the canal wall. To determine the percentage of sealer penetration, the circumference of the root canal wall was outlined and measured with the software measuring tool. Next, areas along the canal walls into which the sealer penetrated the dentinal tubules with any distance were outlined and measured. The outlined distances were divided by the canal circumference to calculate the percentage of sealer penetration. To determine the maximum depth of penetration, the point of deepest penetration was measured from the canal wall to the point of maximum sealer penetration.

 Results



The maximum depth of penetration in the experimental groups is reported in [Figure 1]. Representative pictures from each group are shown in [Figure 2].{Figure 1}{Figure 2}

Percentage of sealer penetration

Kruskal–Wallis analysis of results showed significantly more percentage of sealer penetration in EndoVac group at apical, middle, and coronal one-third with respect to the other experimental groups (P < 0.05) as shown in [Table 2]. However, no significant difference was found between Navi Tip FX and EndoActivator in terms of percentage of sealer penetration at coronal one-third. The Wilcoxon signed-rank tests showed significantly different sealer penetration at apical, middle, and coronal one-third within each experimental group.

Depth of sealer penetration

Kruskal–Wallis detected significant difference among all groups in terms of depth of sealer penetration at apical, middle, and coronal level (P < 0.05) as shown in [Table 3]. Wilcoxon signed-rank test showed that there was no significant difference among EndoActivator and NaviTip FX group at coronal one-third. EndoVac showed significantly greater depth of sealer penetration at all the levels with respect to other groups.

 Discussion



Sealer penetration both in terms of depth and the percentage are important for a successful root canal treatment.[12],[13],[14],[15],[16],[17] Different techniques are available to analyze the sealer penetration such as SEM, light microscope, and CLSM.[16],[17] In the present study, CLSM was used because of its noted advantages over SEM such as no special specimen processing and the observations can be made in near normal conditions.[17]

Apical preparation size in the present study was confined to No. 40/0.06 so that maximum amount of irrigant exchange can occur at the apex. Although no definite guidelines are there for minimum apical preparation for adequate volume of irrigation, in a study by de Gregorio et al.,[18] size 40.04 was found to increase irrigant flow at the apex by 44% so corresponding to that in our study also apical preparation was confined to size 40 and 6% taper. Although the present study focused on sealer penetration inside the dentinal tubules that is inversely proportional to the presence of smear layer and smear layer removal which in turn depends on volume irrigant flow at the apex, apical preparation becomes very critical for the irrigant flow.

The results obtained with the present study were in agreement with the other studies done in the past, that is, higher depth and percentage of sealer penetration was seen at the apical and middle-third with EndoVac followed by EndoActivator and NaviTip with brush irrigation system.[15],[16],[18],[19] At coronal third, not much of difference was seen among the groups. The possible reason of higher sealer penetration at middle and apical third can be attributed to greater smear layer removal and more irrigant reach at these inaccessible areas by using EndoVac, EndoActivator, and NaviTip with brush as compared to conventional irrigation system, that is, 30-gauge NaviTip without brush.[20]

Many factors may influence the percentage and maximum depth of sealer penetration. These factors include the effectiveness of the removal of the smear layer, the obturation technique, the physical and chemical properties of the sealer, and the anatomy of the root canal system.[21] Taking all these factors into considerations, apart from the first factor, that is, effectiveness of removal of smear layer which depended greatly on the irrigation technique being used although the irrigants used in all the groups were same, that is, 3% NaOCl and 17% EDTA, all other factors were at same comparable level in all the groups, that is, cold lateral obturation technique being used in all the groups, AH Plus sealer, and single-rooted mandibular teeth.

The present study was focused on the effectiveness of different irrigation techniques on sealer penetration. The results obtained were significantly in favor of EndoVac system when talking about sealer penetration in the apical and middle third of the root canal system. Possible reason for this can be negative pressure system which is the mainstay of EndoVac system.[5],[20] It has three components, that is, macrocannula, microcannula, and master delivery tip. Master delivery tip constantly delivers the irrigant solution into the root canal, keeping the canals full of irrigants all the time. Macrocannula reaches till the middle third of the root canal and removes the debris attached to the wall simultaneously by moving in up and down motion. Microcannula reaches the apical third of the root canal till the working length and removes the vapor lock effect if any created by the macrocannula.[21]

EndoActivator is an agitating device that agitates the irrigant into the root canal. It was not able to show better results in terms of sealer penetration at apical, middle-third probably because of the complexity and tortuosity of the root canal at these levels which the simple agitation is not able to overcome when compared to apical negative pressure technique that is provided by the EndoVac.[21] This is in agreement with the studies done in the past where EndoVac scores ahead of EndoActivator in terms of sealer penetration and smear layer removal.[22],[23],[24]

Possible reason as to why EndoVac resulted in better sealer penetration in apical third than EndoActivator and Navi Tip with brush is that the tip of the EndoActivator was placed 2 mm from the apex, whereas the microcannula of EndoVac was placed at the working length, thereby eliminating vapor lock effect if any and resulting in greater smear layer removal. Studies have shown that irrigant does not flow beyond 1–1.2 mm from the deliver tip of the conventional 30-gauge needle irrigation technique and same was seen in this study as well.[3]

Within the limitation of this study, we observed that EndoVac system because of it apical negative pressure system was better and superior in terms of depth and percentage of sealer penetration in comparison to EndoActivator, NaviTip with brush, and conventional needle irrigation system at apical and middle thirds of the root canal.In vivo trials on larger scale are recommended for validating the results of this study.

 Conclusion



Within the limitation of the study, we conclude that the percentage and depth of sealer penetration using Endovac irrigation system was significantly better then the other experimental groups at 1mm and 3mm short of the working length. Further studies are needed to evaluate the effect of the EndoVac irrigation system on sealer penetration in complex, narrow, and curved root canals and with bigger sample size.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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