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Year : 2017  |  Volume : 29  |  Issue : 2  |  Page : 130-135

Evaluation of percentage and depth of smartpaste bio versus AH plus sealer penetration using three different activation techniques: A confocal laser scanning microscopic study

Department of Conservative Dentistry and Endodontics, Y. M. T. Dental College, Navi Mumbai, Maharashtra, India

Date of Web Publication6-Nov-2017

Correspondence Address:
Rama Pradeep Mhadgut
19-Sarini, C.H.S, Sector 16A, Vashi, Navi Mumbai - 400 703, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/endo.endo_26_17

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Aim: The aim of the following study was to evaluate the effects of three root canal sealer activation techniques on percentage and depth of penetration of SmartPaste Bio and AH Plus sealers using the confocal laser scanning microscopy (CLSM).
Materials and Methods: Root canals of sixty teeth prepared till rotary F3 ProTaper size were divided into two equal groups on the basis of type of sealer used: AH Plus (Dentsply–DeTrey, Konstanz, Germany) and SmartPaste Bio sealer (Endotechnologies, LLC, Shrewsbury, MA, USA). Sealers were mixed with Rhodamine B for visibility under CLSM. Each group was further divided into three equal subgroups on the basis of sealer activation technique: (i) Sonic, (ii) ultrasonic, and (iii) manual dynamic. The specimens were obturated with gutta-percha by cold lateral condensation. Horizontal sections at 3 mm from the apex were obtained, and the percentage and depth of penetration of sealers into dentinal tubules were measured using CLSM.
Results: Group 1 (ii) showed the highest mean depth of penetration (1260 μm) and maximum mean percentage of sealer penetration (90.004), whereas Group 2 (i) showed minimum mean depth of penetration (492 μm) and minimum mean percentage of sealer penetration (23.7). Statistical significant differences among all the groups were found at the 3 mm level (P < 0.001; analysis of variance - Tukey's tests) for the depth and percentage of sealer penetration.
Conclusion: Percentage and depth of sealer penetration are influenced by the type of sealer used and the sealer activation technique. SmartPaste Bio sealer and ultrasonic method of activation gave best results.

Keywords: Confocal laser scanning microscopy, sealer penetration, SmartPaste Bio, sonic, ultrasonic

How to cite this article:
Hegde V, Jain A, Mhadgut RP. Evaluation of percentage and depth of smartpaste bio versus AH plus sealer penetration using three different activation techniques: A confocal laser scanning microscopic study. Endodontology 2017;29:130-5

How to cite this URL:
Hegde V, Jain A, Mhadgut RP. Evaluation of percentage and depth of smartpaste bio versus AH plus sealer penetration using three different activation techniques: A confocal laser scanning microscopic study. Endodontology [serial online] 2017 [cited 2021 Apr 11];29:130-5. Available from: https://www.endodontologyonweb.org/text.asp?2017/29/2/130/217709

  Introduction Top

Successful endodontic therapy involves complete chemomechanical preparation which may be considered as a crucial step in root canal disinfection. However, it is challenging to achieve total elimination of bacteria from the root canal system.

It is the three-dimensional sealing off of the complex root canal system from the periodontal ligament and bone which ensures the health of the attachment apparatus against the microbes of endodontic origin.[1] Gutta-percha (GP) + AH Plus (Dentsply–DeTrey, Konstanz, Germany) sealer is considered to be a gold standard as an endodontic filling material against which all new sealers can be compared.[2],[3],[4],[5] However, GP has its own disadvantage of being nonadherent to the canal walls. A root canal sealer plays a vital role in enhancing the seal during compaction and to penetrate into small, normally remote areas, i.e., the dentinal tubules.

Ideally, the endodontic sealers used should be able to achieve a good and strong bond between the core filling material and the root dentin. An inadequate sealer coating may result in gaps and porosities at the sealer dentin interface and permit bacterial microleakage which leads to endodontic failure.[6] Therefore, it is important that the percentage of the sealer/dentin interface that is covered by the sealer and the degree of tubule penetration by the sealer is as great as possible in all cases, whether previously infected or not.[7]

From the evolution in the concept of sealers, the introduction of the new hydrophilic material is being employed for obturating the root canals. The recent advancement in endodontic sealers - SmartPaste Bio (Endotechnologies, LLC, Shrewsbury, MA, USA) is a resin-based sealer designed to swell through the addition of ground polymer. It is composed of zirconium oxide, calcium silicate, calcium phosphate monobasic, and calcium hydroxide.[8]

Placement and activation of a sealer into the root canal system should be predictable and should be done to completely cover the dentin walls. The various recognized modes of sealer placement include the use of endodontic files or reamers, lentulo spirals, GP cones, paper points, ultrasonic files, and counterclockwise motion of rotary systems.[9] Each technique may produce a different distribution of the sealer onto the canal walls, ultimately which may affect the sealing. At present, there is no evidence to suggest that one method is better and reliable than others.

Stereomicroscopy, scanning electron microscopy (SEM), transmission electron microscopy, and confocal laser scanning microscopy (CLSM) are the different microscopy techniques that are currently used to evaluate the sealer/dentin interface. However, the CLSM has the advantage of providing detailed information of the root canal walls at a relatively low magnification in comparison to conventional SEM.

Therefore, the purpose of this study was to evaluate percentage and the depth of dentinal tubule sealer penetration of SmartPaste Bio sealer when agitated with three different techniques and to compare it with AH Plus sealer using CLSM for evaluation. The null hypotheses to be tested were that the use of ultrasonic, sonic, and manual dynamic techniques have no statistically significant influence on the sealer penetration in the dentinal tubules.

  Materials and Methods Top

Sample preparation

Sixty freshly extracted single-rooted and single canal teeth were verified buccolingually and mesiodistally by radiovisiography (Kodak Carestream 5100) and stored in normal saline. Only teeth with intact and mature root apices were selected and samples exhibiting any visible root caries, fractures, cracks, and signs of defects were excluded from the study. Only root canals, in which the first file that has snug fit at the apex was size 20 were included in this study to maintain the uniformity in the apical width. The teeth were decoronated to achieve an approximate root length of 15 mm, using a low-speed diamond disc under water cooling.

Root canal preparation

A size #10 K-file (MANI) was inserted into the root canal until it was just visible at the apical foramen and the working length was established 1 mm short from the anatomic apex. The root canals were prepared 1 mm short of this length first by creating a glide path till #25 K-file followed by full sequence of ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) rotary instrumentation #SX-F3. After each instrument, the canals were irrigated with 2 ml 5.25% sodium hypochlorite (NaOCl) using a side venting needle kept 2 mm short of the apex, and ethylenediaminetetraacetic acid (EDTA) gel (RC Help, Prime Dental, India) was used as a lubricant throughout the procedure. After complete instrumentation, all samples were flushed with 5 ml 17% EDTA solution (Dent Wash, Prime Dental, India) (1 min) and then with 5 ml 5.25% NaOCl (1 min). This rinse was activated by the ultrasonic tips – IrriSafe tips (Satelec, Acteon group, Merignac, France) attached to the handpiece of an ultrasonic unit (Satelec) with power setting adjusted to level 5 (in a range of 1–10). The final rinse was done with 5 ml normal saline and samples dried with the absorbent paper points. The samples were then randomly divided into two groups (thirty samples each) according to the sealer used: Group 1: SmartPaste Bio sealer (Endotechnologies, LLC, Shrewsbury, MA, USA) and Group 2: AH Plus sealer (Dentsply–DeTrey, Konstanz, Germany). The groups were further subdivided (ten samples each) according to the sealer placement technique: (i) Sonic - Endoactivator (Dentsply Tulsa Dental Specialities), (ii) ultrasonic - IrriSafe tips (Satelec, Acteon group, Merignac, France) mounted on a Suprasson P5 Booster ultrasonic unit (Satelec), and (iii) manual dynamic-master GP cone (Meta – Biomed).

  • Group 1: SmartPaste Bio sealer + Rhodamine B dye (thirty samples)

    1. Sonic (ten samples)
    2. Ultrasonic (ten samples)
    3. Manual dynamic (ten samples).

  • Group 2: AH Plus sealer + Rhodamine B dye (thirty samples).

    1. Sonic (ten samples)
    2. Ultrasonic (ten samples)
    3. Manual dynamic (ten samples).

    Sealer placement

    SmartPaste Bio sealer and AH Plus sealer were mixed according to the manufacturer's instructions, and each sealer was labeled with Rhodamine B (Mayor Diagnostics, Mumbai, India) to an approximate concentration of 0.1% (by weight) to facilitate analysis under the CLSM. This mixture of fluorescent dye and sealers was placed along the entire length of the canals using the lentulospiral.

    After the placement of SmartPaste Bio sealer and AH Plus sealer, the sealer was activated according to the subgroups.

    • EndoActivator (Dentsply Tulsa Dental Specialties) tip – medium tip (25/04) was set to reach within 1 mm of working length, and EndoActivator was slowly rotated for 20 s for both the sealers
    • Ultrasonic activation was performed using a stainless steel, noncutting, ultrasonic IrriSafe #20/25 mm tips (Satelec, Acteon group, Merignac, France) mounted on a Suprasson P5 Booster ultrasonic unit (Satelec) at a power setting of five. The file was inserted passively 1 mm short of the working length and was activated for a period of 20 s for each sealer
    • For manual dynamic activation of the sealer, F3 master GP cone was selected with proper tug-back. The cone was kept 1 mm short of the working length, and the sealers were manually activated. The frequency of activation used was 100 push-pull strokes per minute. Four GP cones per root were used.

    In each group after sealer placement, the master cone was placed in the canal to the length and laterally condensed with the finger spreader, and accessory GP cones were added as needed. Two millimeters of GP was seared off from the orifice with a heated plugger and was filled with Cavit. The excess sealer was wiped off from the apex by a moist cotton. The samples were stored at 37°C and 100% humidity for 7 days to ensure adequate setting of the sealers.

    Sectioning and image evaluation

    The roots were sectioned at 90° to their long axis with a diamond disk removing one section, 3 mm from the apex. Sandpaper was used to polish the coronal surface of each section. Each section was then examined under the CLSM (Leica SP5 X) under the ×10 lens. The respective absorption and emission wavelengths for the Rhodamine B were 540 nm and 590 nm. Each image was imported into the Image J software (Wayne Raspand) 2010 to calculate the percentage of sealer penetration around the root canal, and the circumference of root canal was measured using its ruler tool. The same method was used to outline and measure the areas along the canal walls, in which the sealer penetrated into the dentinal tubules. Subsequently, the percentage of root canal sealer penetration in that section was established. To determine the maximum depth of penetration, the point of deepest penetration was measured from the canal wall to the maximum depth of penetration. The effects of sealer agitation techniques and type of sealer on depth and percentage using two-way analysis of variance followed by Tukey's test were analyzed; the level of significance was set at P < 0.001.

      Results Top

    From all the sixty sections scanned, a consistent fluorescent sealer ring was seen around the canal in all ×10 sections [Figure 1]a. Sealer penetration in the dentinal tubules was seen in all the sections [Figure 1] and [Figure 2]. The mean and standard deviation of depth of sealer penetration and percentage of sealer penetration are presented in [Table 1] and [Graph 1], and intergroup comparison is summarized in [Table 2]. The result shows that ultrasonic when used for agitation showed highest mean percentage and depth of sealer penetration of SmartPaste Bio and AH Plus sealers and statistically significant (P< 0.001) than sonic and manual dynamic techniques. Irrespective of method used for agitation, the percentage and depth of sealer penetration for SmartPaste Bio were significantly greater (P< 0.001) than AH Plus.
    Figure 1: Sealer tags penetrating into dentinal tubules at 3-mm level. (a) SmartPaste – Bio; ultrasonic (Group 1 [i]), (b) SmartPaste – Bio; sonic (Group 1 [ii]), (c) SmartPaste – Bio; manual dynamic (Group 1 [iii])

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    Figure 2: Sealer tags penetrating into dentinal tubules at 3-mm level. (a) AH Plus; ultrasonic (Group 2 [i]), (b) AH Plus; sonic (Group 2 [ii]), (c) AH Plus; manual dynamic (Group 2 [iii])

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    Table 1: Mean and standard deviation of depth of sealer penetration and percentage of sealer penetration of the various groups at 3 mm level

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    Table 2: Intergroup comparison of depth and percentage of sealer penetration at 3 mm level

    Click here to view

      Discussion Top

    The prime purpose of the endodontic therapy is to provide a fluid tight seal of the root canal space and prevent reinfection of the root canal. This seal is achieved by a combination of the core material and an endodontic sealer. However, the core material by itself is unable to achieve this seal which can lead to the undesirable communication between the canal space and the periradicular tissues.

    Thus, the sealer plays a pivotal role to seal this communication leading to a good prognosis for tooth. It provides an impervious seal, fills the irregularities and minor discrepancies between the root canal wall and core filling material, and assists in microbial control if microorganisms were left on the root canal walls or in the tubules.[6] There are studies which confirm the fact that teeth obturated with just the core material without a sealer results in an increased leakage.[10],[11]

    Therefore, the penetration of sealer into dentinal tubules is considered to be a desirable outcome for a number of reasons: It will increase the interface between material and dentin, thus improving the sealing ability and retention of the material may be improved by mechanical locking and also enhances the reinforcement of the tooth. Sealer within dentinal tubules may also entomb any residual bacteria within the tubules, and the chemical components of sealer may exert an antibacterial effect that will be enhanced by closer approximation to the bacteria. Thus, both percentage and depth of sealer penetration might influence the outcome or success rate of endodontic therapy.[7]

    Apical third of the root canal is considered to be the most critical area and varies due to the presence of the apical deltas, lateral canals, anastomosis, fins, and isthmi from the early work of Hess and Zurcher.[12] Thorough sealing of this region is a crucial task with the routine obturation procedure. If failed to seal accurately, the communication can lead to periodontal–endodontic pathway leading to bacterial infection. Hence, the apical 3 mm of the section was chosen to evaluate the sealer penetration.

    SmartPaste Bio, a newly introduced sealer based on bioceramic technology, is showing promising results. Studies based on the physical properties reported significantly greater flow of SmartPaste Bio than AH Plus.[2] Therefore, this comparative study was conducted to evaluate and compare the quality of seal of AH Plus and SmartPaste Bio sealer.

    According to this study, SmartPaste Bio showed significantly better (P< 0.001) percentage and depth of sealer penetration than AH Plus with all the techniques of sealer activation. This could be attributed to its properties such as remarkable flowability due to its nanoparticle size and hydrophilicity, slight expansion on setting, and low contact angle.

    Clinically, rapid insertion or activation of a pseudoplastic sealer into the canal would decrease viscosity and increase the flow of sealer. Very few studies [6],[9],[13],[14] have been conducted on the effect of sealer activation/placement and activation on sealing ability of root canal sealers. Therefore, in the present study, three activation techniques (ultrasonic, sonic, and manual dynamic) were chosen, and the sealer distribution was analyzed. The amount of sealer, extent of activating instrument, and time for activation were standardized to minimize the errors.

    Various studies have advocated the use of ultrasonic for sealer placement.[7],[10],[15],[16] Like Ultrasonic, for activation of the irrigants, the EndoActivator System is also utilized.[7],[13] The results of this study demonstrate that overall, the ultrasonic group showed better depth and percentage of sealer penetration than sonic group followed by the manual dynamic group, substantiating the findings of previous studies. Ultrasonic energy is based on the principle that it causes acoustic microstreaming of the sealer when activated. The oscillations running throughout the length of the ultrasonic tip caused rapid movement of the sealer and drove it deeper into the dentinal tubules. The EndoActivator System (Dentsply Tulsa Dental Specialities, Tulsa, OK, USA) which was introduced is a sonically driven canal irrigation system, and its hydrodynamic activation is used for sealer placement in the canal.[17] Sonic energy produces - just one single node and antinode over the entire length of vibrated instrument. Hence, its streaming velocity is less than the ultrasonic devices. A minimum oscillation of the amplitude might be considered a node, whereas a maximum oscillation of the amplitude represents an antinode. They have one node near the attachment of the file and one antinode at the tip of the file. Contact between the tip and dentin results in diminished amplitude and undesirable decrease in streaming velocity. Ultrasonic energy has the ability to set up characteristic pattern of several nodes and antinodes along their length. The ultrasonic tip in the ultrasonic system is made of metal alloys, whereas EndoActivator has polymer-based tips.[18] The difference in their materials might have also influenced the displacement of sealer. All these might have contributed to better penetration of the sealer by the ultrasonic system. The ultrasonic and sonic energy apparently propels the relatively viscous sealer along the length of file to appropriate depth, whereas master cone pushes the sealer laterally.

    Among the different tools available for evaluation, CLSM provides detailed information about the presence and distribution of sealers inside dentinal tubules. This is in the total circumference of the root canal walls at relative low magnification through the use of fluorescent Rhodamine-marked sealers.[19],[20] In addition, it uses nondecalcified or hard tissue samples that do not require a specific section technique (sputter coating).

    In the present study, depth and percentage of sealer penetration were addressed in the apical third of teeth with single straight canal. It is important to emphasize that the results of thisin vitro study cannot be directly extrapolated to all clinical conditions where the root canal morphology variation, the different obturating techniques, sealer extrusion, and various such factors may result in a different outcome.

      Conclusion Top

    Under the limitations of the present study, it can be concluded that type of sealer placement techniques influences and enhances both the depth and the percentage of sealer penetration. SmartPaste Bio sealer presented better depth and percentage of sealer penetration in the radicular dentinal tubules than AH Plus sealer. Ultrasonic activation of sealer significantly increased the depth and percentage of the sealer. Further studies are required to conclude and analyze the depth and percentage of sealer along the entire length of the canal for successful nonsurgical endodontic results.

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    Conflicts of interest

    There are no conflicts of interest.

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      [Figure 1], [Figure 2]

      [Table 1], [Table 2]


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