| Abstract|| |
Background: Endodontically treated teeth with extensive loss of tooth structure lacks sufficient support for a permanent restoration. While restoring them with post and core it is important not to disrupt the apical seal.
Aim: Evaluation of apical leakage after immediate and delayed postspace preparation using two root canal sealers.
Materials and Methods: Sixty single-rooted teeth were decoronated and roots were biomechanically prepared and obturated with gutta-percha and 2 sealers: AH Plus (Group A, n = 30) and Sure-Seal root canal sealer (Group B, n = 30). Groups A and B were subdivided into A1, A2 and B1, B2. Postspace was prepared immediately for A1 and B1. For A2 and B2 post space was prepared after storage in physiologic saline for 1 week. The samples were kept in Rhodamine B dye for 72 h and then sectioned longitudinally to observe dye penetration along the root canal wall under Stereomicroscope. The dye penetration was measured linearly and the values were subjected for statistical analysis using one-way analysis of variance and t-test.
Results: Statistically significant difference between Group A (1.00 mm) and B (2.71 mm) was observed (P < 0.001). However, the subgroups for immediate and delayed post space preparation did not show statistically significant difference (A1 = 0.947; A2 = 1.043; B1 = 2.306 and B2 = 3.120, P < 0.001).
Conclusion: AH plus sealer showed lesser leakage compared to Sure-Seal Root canal sealer. The difference in leakage values was not statistically significant in delayed and immediate post space preparation groups, Time of postspace preparation has no influence on apical leakage.
Keywords: AH plus; immediate and delayed postspace preparation; microleakage; sure seal root
|How to cite this article:|
Gujarathi NN, Mandlik J, Singh S, Chaubey S. Evaluation of apical leakage after immediate and delayed postspace preparation using different root canal sealers: An in vitro study. J Conserv Dent 2021;24:174-8
|How to cite this URL:|
Gujarathi NN, Mandlik J, Singh S, Chaubey S. Evaluation of apical leakage after immediate and delayed postspace preparation using different root canal sealers: An in vitro study. J Conserv Dent [serial online] 2021 [cited 2021 Nov 30];24:174-8. Available from: https://www.jcd.org.in/text.asp?2021/24/2/174/327851
| Introduction|| |
The long-term success of an endodontic therapy depends upon the three-dimensional root canal filling and ability to maintain an apical seal. Failure to maintain the apical seal results in reinfection of the tooth requiring retreatment. Therefore, the sealing ability of the root canal filling material must be evaluated meticulously. A proper apical seal prevents the entry of microbes or any infective material and exudates from the periradicular areas into the root canal and vice versa from the root canal into the periradicular space. Hence, a fluid-tight apical seal is mandatory. Usually, the leakage occurs either at the gutta-percha/sealer interface or sealer/dentin interface. Hence it is clear that bonding of the sealer to the dentinal wall is important.
AH Plus (Dentsply DeTrey, Konstanz, Germany) is an epoxy resin-based sealer. It is hydrophobic and has an extremely low shrinkage making it a suitable choice for sealing the root canal. Because of its self-adhesive properties and dimensional stability, it achieves a tight seal. It exhibits moderate anti-microbial properties and is biocompatible. It is clearly visible on radiographs as it is extremely radiopaque. Due to these properties, it is considered to be a gold standard for comparisons with other endodontic sealers.,, Sure-seal root canal sealer (Sure Dent Corp., Gyeonggi-do, Korea) is a hydrophilic bioceramic sealer containing calcium silicate material. It has a unique property of chemical adhesion with no shrinkage thus providing superior sealing properties. It is biocompatible and has superior antibacterial properties (over pH 12).
The teeth with extensive loss of coronal tooth structure are more prone to fracture after endodontic treatment. In such teeth post and core restorations are often indicated to restore the functions. While preparing the postspace care should be taken to not to disturb the integrity of the apical seal. According to many studies, 4–5 mm of gutta-percha should be kept for maintaining an adequate apical seal.,, The method used for removing the root canal filling material, the amount of gutta-percha retained in the canal, post space preparation timing, sealer type, and technique for obturation used can affect the outcome of the endodontic therapy.
The aim of this study is to evaluate the effect of different time intervals of postspace preparation on maintaining the apical seal by using AH Plus sealer and Sure seal root canal sealer.
| Materials and Methods|| |
Single rooted non carious teeth with single canal extracted for orthodontic and periodontal reasons were selected. After extraction, the soft tissues, calculus, and stains were removed and the teeth were stored in normal saline till further use. Teeth with visible cracks or defects, curved roots, multiple/bifurcated canals, immature apex, and resorptive defects were excluded.
The teeth were decoronated at the cementoenamel junction with a slow-speed diamond disc under constant water cooling. Working length was determined by placing a size 15 K-file (Mani Inc. Japan) into the canal until the file tip was visible at the apical foramen. 1 mm was subtracted from this length to obtain the final working length. Instrumentation of canals was done using ProTaper instruments (Dentsply Maillefer) till F2. During instrumentation 17% EDTA gel (RC Help) was used as a lubricant. After the use of each instrument, the canals were irrigated with 5% sodium hypochlorite solution. The canals were finally rinsed with sterile saline to remove any dentin debris that remained in the canal after instrumentation. The experimental root-canal sealers were mixed as instructed by the manufacturers. Root canal obturation was done. The postobturation radiographs were taken to assess the quality of the obturation. The postspace preparation in all the samples was made according to the study protocol. Coronal 2–3 mm of the gutta-percha was removed and the coronal end of the canals were sealed with Cavit-G. The samples for the delayed postspace preparation were stored in normal saline for a week. The postspace in each sample was prepared with Peeso reamer. The size of the Peeso reamer was determined according to the original canal size (from size 1–4) to a depth that will leave a minimum of 5 mm of gutta-percha apically.
Samples were randomly assigned into two main groups (n = 30). Each of these groups was then divided into two subgroups to receive the treatment as follows:
- Group A1: Gutta-percha + AH plus sealer followed by immediate postspace preparation
- Group A2: Gutta-percha + AH plus sealer and the post space preparation was done 1 week after the obturation
- Group B1: Gutta-percha + sure seal root canal sealer followed by immediate post space preparation
- Group B2: Gutta-percha + sure seal root canal sealer and the postspace preparation was done 1 week after the obturation.
After postspace preparation, the access cavities were sealed with Cavit G. The samples were coated with two layers of nail varnish covering it entirely including the access restoration except apical 2 mm. The samples were then immersed in Rhodamine dye for 72 h. Finally, to remove any excess dye, the samples were washed in running tap water. Scalpel was used to remove the nail varnish. The samples were then ground longitudinally at high speed under constant water cooling with a cylindrical diamond disc until the root canal filling was reached on one side, whilst keeping a thin layer of apical dentin intact. This deeper layer of dentin was removed without the water cooling using a diamond disc at low speed.
Sections were examined under the stereomicroscope (Wuzhou New Found Instrument Co. Ltd., China Model: XTL 3400E) at ×10 magnification. The depth of dye penetration was measured linearly from the apical root end to the maximum extent of penetration of dye in the coronal direction with Image Analysis System (Chroma Systems Pvt., Ltd., India. Model: MVIG 2005). The measurements of dye leakage (in mm) were recorded and subjected to statistical analysis.
| Results|| |
Descriptive statistics were used to describe the data. Mean and standard deviation was used to describe the numerical data. The normality of data was checked by Shapiro-Wilk tests. Independent sample t-test was used to compare two independent numeric groups. One-way analysis of variance was used to compare more than two independent numeric groups. P <0.05 were considered as significant values.
[Table 1] shows the mean microleakage and standard deviation for Groups A and B. By using Independent t-test, it was observed that there was a statistically significant difference in the values of microleakage for both the groups. Group B (Sure Seal, 2.71 mm) showed higher microleakage than Group A (AH Plus 1.00 mm) (P < 0.001) [Graph 1]. [Table 2] shows statistically significant difference between Group A1, Group A2, Group B1, and Group B2 (P < 0.001). However, there were no significant differences in immediate and delayed postspace preparation for both groups (Group A: A1-0.94 and A2: 1.04 mm); (Group B: B1-2.30 and B2-3.12 mm). Microleakage value was higher in Group B2 compared to all the groups, it was followed by Group B1, A2, and A1, respectively [Graph 2].
|Table 1: Comparison of apical microleakage (mm) for the main groups using independent t-test|
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|Table 2: Comparison of apical microleakage (mm) for sub-groups using one-way analysis of variance|
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| Discussion|| |
This in vitro study was intended to compare the newly introduced Sure Seal root canal sealer with the commonly used AH Plus for its sealing ability. Results of this in vitro study showed apical dye leakage in all four groups. As far as the sealer was concerned, Sure Seal root canal sealer (Group B; 2.71 mm) had higher mean microleakage than the AH Plus sealer (Group A; 1.00 mm).
Sealing ability of the sealer can be related to different factors such as micromechanical bonding, chemical bonding. Sure-Seal (Sure Dent Corp., Gyeonggi-do, Korea) is a recently introduced premixed, injectable bioceramic sealer containing calcium silicate material. It is osteogenic, biocompatible, highly antibacterial (pH = 12), and hydrophilic. The manufacturers claim that it has excellent physical properties with no shrinkage during setting. It has good dentinal bond strength. As per these claims, the Sure-Seal root canal sealer is expected to show minimum apical leakage, however, in our study, it showed more leakage than AH Plus sealer. AH Plus produces rigid and strong cross-linked polymer with dentin collagens, hence it must have showed less microleakage.
Very few studies are conducted on Sure Seal root canal sealer but they evaluated dentinal tubule penetration, anti-bacterial properties and ability to be removed from root canals during retreatment. Recently, Pramudita et al. evaluated sealing ability of Sure-Seal Root canal sealer and compared it with mineral trioxide aggregate. Sure-Seal root canal sealer showed better results in this study. Our results are contradictory to this study. The reason for more microleakage with Sure-Seal might be due to its hardening in moist environment from the root canal. When working in vitro, it is difficult to condition the teeth with 100% humidity to match in vivo conditions, which might affect the time and level of hardness of the root canal sealer in the teeth.
AH Plus sealer is epoxy resin-based and has various advantages such as high radiopacity, good tissue compatibility, low solubility, and little shrinkage. When compared in an in vitro adhesion test with other types of cements, epoxy resin sealers have shown to have strong adhesion to both dentin and gutta-percha. This was attributed to the ability of the resin to react with any exposed amino groups in collagen to form covalent bonds with dentin when the epoxide ring opens whereas stronger adhesion between sealer and gutta-percha was ascribed to the light acidic pH and a potential chemical bonding because of ring-opening.
There are a number of tests used to determine the sealing ability of the root canal filling materials; i.e., dye penetration method, radioactive isotope penetration method, fluid filtration method, and scanning electron microscopic analysis., Dye penetration test is most commonly used as it is a simple, inexpensive, and oldest method to study microleakage. It is a passive method which depends on capillary fluid movement. In this study, we used the dye penetration technique.
According to the study protocol, postspace preparation was done after 1 week in Groups A2 and B2 (delayed). For the delayed group, the samples were stored in normal saline at 37°C for a week. This was to allow sealers to set completely and avoid any evaporative loss of water during measurements.
Although the apical leakage values of immediate and delayed postspace preparation groups were not statistically significant, lesser leakage was observed when post preparation was done immediately. The reason for this may be that when a postspace was prepared immediately after filling, the sealer was still within its working time, allowing the sealer to set without introducing microcracks whereas in delayed postspace preparation sealer had set completely and it was possible that the rotational effect of Peeso reamers may have caused movement of gutta-percha and developing microcracks within set sealer, thus breaking the bond at the sealer dentine interface resulting in more leakage.
There are enough studies done on the effect of immediate and delayed postspace preparation on apical leakage. In an ex vivo study by Lyons et al., there was no significant difference between immediate and delayed postspace preparation using Resilon/Epiphany. Similar results were obtained by Saunders et al., Rybicki and Zillich et al., Madison and Zakariasen. Our results were in accordance with these studies.
This being an in vitro study, effects of other factors in the oral environment like oral fluids, tissue fluids, or periapical fluids on the sealing ability of sealers could not be evaluated. These in vitro results cannot be extrapolated to in vivo situations, but they do permit reasonable comparison. Hence, further investigations are required to validate the choice of sealer during obturation and timing of postspace preparation.
| Conclusion|| |
Within the limitations of this in vitro study, it can be concluded that:
- Apical leakage was observed in all the groups irrespective of the sealers irrespective of the sealers used and time of postspace preparation
- AH Plus sealer showed lesser apical leakage than Sure-Seal Root canal sealer in both the sub-groups (immediate and delayed postspace preparation groups)
- Apical leakage in the immediate postspace preparation group was lesser than delayed postspace preparation group for both the sealers, however, the difference was not statistically significant.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Dr. Nirmitee Narendra Gujarathi
12, Vijay Housing Society, Vidyapeeth Road, Pune - 411 016, Maharashtra
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2]