ORIGINAL RESEARCH

https://doi.org/10.5005/jp-journals-10015-2566
World Journal of Dentistry
Volume 16 | Issue 1 | Year 2025

Comparative Evaluation of Retreatability of Two Bioceramic Sealers and Epoxy Resin Sealer with Two Different File Systems: An In Vitro Cone Beam Computed Tomography Volumetric Analysis

Riya Jain1, Rashmi Nair2, Neetu Maurya3, Neha D Singh4, Labdhi Maloo5, Shanu Khan6

1–6Department of Conservative Dentistry and Endodontics, Chhattisgarh Dental College and Research Institute (CDCRI), Rajnandgaon, Chhattisgarh, India

Corresponding Author: Rashmi Nair, Department of Conservative Dentistry and Endodontics, Chhattisgarh Dental College and Research Institute (CDCRI), Rajnandgaon, Chhattisgarh, India, Phone: +91 9630145664, e-mail: rashmi.a.nair@gmail.com

Received: 01 January 2025; Accepted: 06 February 2025; Published on: 13 March 2025

ABSTRACT

Aim: To compare and evaluate the removal of CeraSeal, Bioceramic Sealer, and AH Plus for retreatment using two rotary retreatment systems—R-Endo and GPR files.

Materials and methods: Depending on the sealer used for obturation, a total of 54 extracted mandibular permanent premolars were instrumented with ProTaper files up to F3. Samples were divided into three groups (n = 18 each): group I—CeraSeal group; group II—Bioceramic (Prashanti) group; group III—AH Plus group. The samples were then subjected to cone beam computed tomography (CBCT) imaging to calculate the volume of the filled material. The specimens in each group were then further divided into two subgroups (n = 9 each) based on the retreatment file system employed: (A) R-Endo files, (B) GPR files. All the samples were evaluated for remnants of filling material by CBCT imaging. The results were analyzed using one-way analysis of variance (ANOVA), followed by a post hoc Tukey test.

Results: When comparing the sealers’ retrievability, R-Endo demonstrated superior removal efficiency in all sealers, with a statistically significant difference. Group IIA showed the highest removal efficiency (96.35%), whereas group IIIB showed the lowest removal efficiency (67.80%).

Conclusion: CeraSeal and Bioceramic Sealer were removed more easily compared to AH Plus Sealer. When comparing the retreatment file system, R-Endo showed better removal efficiency than Mani GPR.

Clinical significance: The retrievability of Bioceramic Sealer can be difficult since it bonds with dentin via a mineral infiltration zone. This can present a potential challenge during retreatment procedures. Additionally, understanding the efficiency of R-Endo and the GPR file system in removing obturating material is essential for clinicians to effectively choose and respond to such challenging scenarios when encountered.

Keywords: Bioceramic sealer, Cone beam computed tomography, Epoxy resin sealer, Retreatment file systems, Retrievability

How to cite this article: Jain R, Nair R, Maurya N, et al. Comparative Evaluation of Retreatability of Two Bioceramic Sealer and Epoxy Resin Sealers with Two Different File Systems: An In Vitro Cone Beam Computed Tomography Volumetric Analysis. World J Dent 2025;16(1):56–61.

Source of support: Nil

Conflict of interest: None

INTRODUCTION

The main objective in a nonsurgical orthograde retreatment procedure is the removal of the root canal filling material along with thorough debridement and reshaping of the canal to gain access to the apical area,1 so that the persistent bacterial population can be eliminated, eventually inducing favorable conditions for periradicular healing.2

Calcium silicate-based sealers (CSBS) are known for their biocompatibility, biomineralization, superior bond strength, and sealing ability equivalent to epoxy resin–based sealers.1,3 However, there are limited studies available regarding the removal of CSBS during retreatment. There are concerns that CSBS may resist removal from the root canal dentin, as it interacts and creates intratubular dentinal tags along with an intermediate mineral interaction stratum termed the ”mineral infiltration zone.”4,5 Epoxy resin–based sealers are widely used for their superior physicochemical and antibacterial characteristics.6 Numerous investigators have evaluated the retrievability of epoxy resin-based sealers, but limited studies are available on the removal of Bioceramic Sealers.

Various hand and rotary instruments have been proposed to remove filling materials, such as endodontic hand files, engine-driven rotary files, ultrasonic tips, and heat-carrying instruments. However, nickel-titanium instruments are more effective at removing gutta-percha from the root canal compared to hand instruments.7 Some systems are specially designed for retreatment, including Mtwo retreatment files, ProTaper universal retreatment files, WaveOne, and HyFlex NT. However, well-compacted obturation resists instrumentation. To enable easier penetration of instruments inside the obturated canal, chemical solvents are selected and used as adjuncts to remove endodontic filling materials. Current literature shows that only a few studies have compared the efficiency of R-Endo and GPR file systems in the removal of obturating material.

The efficacy of retreatment procedures can be assessed by the amount of residual gutta-percha and sealer on the root canal walls. Among different techniques employed to assess the quantity of remaining filling material, three-dimensional cone beam computed tomography (CBCT) is a noninvasive, high-resolution imaging method that provides accurate quantitative analysis.7,8

The need for this study arises from the limited research available on the retrievability of epoxy resin-based sealers and Bioceramic Sealers. Current literature shows that only a few studies have compared the efficiency of R-Endo and GPR file systems in the removal of obturating material.

The aim of this study is to compare and evaluate the removal of CeraSeal, Bioceramic Sealer, and AH Plus for retreatment using two rotary retreatment systems—R-Endo and GPR files.

In the present study, the null hypothesis claims that no significant difference exists in root canal filling residues across different sealers and retreatment file systems.

MATERIALS AND METHODS

The study was approved by the Institutional Ethics Committee (CDCRI/DEAN/EC/CONS-02/2022) and was undertaken in the Department of Conservative Dentistry and Endodontics, Chhattisgarh Dental College and Research Institute, Sundra, Chhattisgarh, India. The duration of the study was 6 months.

Fifty-four extracted human permanent teeth with a single root and a single canal, which were extracted for orthodontic reasons, were collected from the Department of Oral and Maxillofacial Surgery of the same institute. Digital radiographs (RVG, Nanopix) were taken from buccolingual and mesiodistal directions to ensure that they had single canals. The samples were then disinfected by immersion in 3% NaOCl for a week and subsequently stored in 0.9% normal saline until use.

Exclusion criteria included the presence of severe root curvature, canal blockage, teeth with multiple root canals, and open apices. The samples were standardized to an average length of 14 ± 1 mm using a diamond disk.

The patency of the apical foramen was verified with a #10 K-file placed just beyond the foramen, and the working length (WL) was measured as 1 mm short of it. To prepare the canals, a ProTaper rotary file (Dentsply-Maillefer, Ballaigues, Switzerland) was used up to F3 with a brushing motion.

Irrigation was performed with 2 mL of 5.25% NaOCl solution after using each instrument. A final rinse was done with 1 mL of 17% EDTA followed by 2 mL of 3% NaOCl for 30 seconds using a 30-gauge single-side vented irrigation needle, precisely kept 1 mm short of the apical foramen. The samples were then flushed with normal saline, and paper points were used to dry the canals.

Size F3 ProTaper gutta-percha cones (Dentsply-Maillefer, Ballaigues, Switzerland) were selected, ensuring adequate fitting, and confirmed with an apical tug-back.

On the basis of sealer used for obturating, the samples were then allocated into three groups (n = 18 each):

The intraoral tips of CeraSeal and Bioceramic Sealers were placed into the coronal third of the respective canals, and a small amount of sealer was dispensed. The canals were then obturated with GP and seared off using a heat source.

AH Plus was mixed using an automixing syringe. A Lentulo spiral (Dentsply-Maillefer, Ballaigues, Switzerland) was used to place the sealer into the canal. Thereafter, obturation was completed using a GP cone.

To allow complete setting of the sealer, all samples were temporarily sealed and incubated for 3 weeks at a temperature of 37°C with 100% humidity. The samples were then mounted using modeling wax for CBCT imaging and volume rendering to calculate the quantity of the filled root canal material in each sample using OnDemand3D dental software (CyberMed, Seoul, Korea) (Fig. 1).

Fig. 1: Reconstructed 3D CBCT images of selected specimens before retreatment

According to the retreatment file system employed, the samples were subsequently segregated into two subgroups (n = 9 each):

Retreatment with R-Endo Files

In the samples of group A, the R-Endo system (Micro-Mega, Besançon, France) was used for retreatment. The file system consists of Rm, R1, R2, and R3 files, which operated with a moderate back-and-forth movement on the canal walls, rotating at a 350-rpm speed and applying 1.5 N·cm² of torque. First, the Rm file was used to create a pilot hole, and then 2–3 mm of obturation material was removed using the other files.

Retreatment with Mani GPR Files

In the samples of group B, retreatment was performed using the Mani GPR file system (Mani Inc., Utsunomiya, Japan). The procedure was carried out using the 2S (50/0.04) file at a speed of 1,000 rpm and 2 Ncm² of torque, followed by the 3N (40/0.04) instrument placed 2 mm short of WL. Then, the 4N instrument was used up to 1 mm short of the minor diameter.

Finally, a ProTaper rotary file (Dentsply-Maillefer, Ballaigues, Switzerland) up to F3 was used for apical preparation to reestablish the working length, following the same irrigation protocol previously applied. The retreatment procedure was considered complete when no filling remnants were observed on the file, and a smooth canal wall was achieved.

CBCT imaging was performed using the identical parameters and settings as in the previous scan to evaluate the remaining obturating material, and measurements were standardized in cubic millimeters. Volumetric analysis of the remnant filling material in each specimen was conducted using OnDemand3D software (CyberMed Inc., Korea) (Fig. 2).

Fig. 2: Reconstructed 3D CBCT images of selected specimens after retreatment with remaining filling material

Outcome Assessment

The removal efficacy was calculated as [(a – b) × 100/a], where a denotes the volume of obturating material and b denotes the remnant volume after retreatment.

Statistical analysis was carried out using SPSS (Statistical Package for the Social Sciences, IBM, version 25). All quantitative variables were estimated using measures of central location (mean) and measures of dispersion (standard deviation). Mean values were compared using one-way analysis of variance (ANOVA). The data evaluated were nonnormally distributed; thus, a post hoc Tukey test was performed for post hoc measurements and inferential statistics. The results were expressed in terms of mean and standard deviation. Statistical significance was considered at 0.05, that is, p < 0.05.

RESULTS

The result illustrated that none of the studied groups showed thorough removal of obturating material after the retreatment procedure. The removal efficiency was seen as maximum in group IIA (96.35 ± 2.09), followed by group IA (91.95 ± 4.31), group IIB (83.91 ± 5.81), group IB (82.49 ± 5.29), group IIIA (82.39 ± 3.50), and the minimum was in group IIIB (67.80 ± 8.22).

On comparing the retrievability of sealers, it was observed that group IIA exhibited the highest removal efficiency (96.35%), while group IIIB demonstrated the least removal efficiency (67.80%) (Tables 1 and 2).

Table 1: Mean and standard deviation obtained from various groups
N Mean Std. deviation Std. error 95% confidence interval for mean
Lower bound Upper bound
Group IA 9 91.95 4.31 1.436 88.6468 95.2728
Group IB 9 82.49 5.29 1.763 78.4312 86.5666
Group IIA 9 96.35 2.09 0.697 94.7491 97.9672
Group IIB 9 83.91 5.81 1.937 79.4462 88.3832
Group IIIA 9 82.39 3.50 1.168 79.7022 85.0899
Group IIIB 9 67.80 8.22 2.741 61.4881 74.1300
Table 2: Post hoc Tukey for multiple comparison between the groups
Groups Mean difference Sig. (p < 0.05)
Group IA–group IIA –4.39 0.487
Group IA–group IIIA 9.56* 0.004
Group IIA–group IIIA 13.96* 0.000
Group IB–group IIB –1.41 0.992
Group IB–group IIIB 14.68* 0.000
Group IIB–group IIIB 16.10* 0.000
Group IA–group IB 9.46* 0.005
Group IIA–group IIB 12.44* 0.000
Group IIIA–group IIIB 14.58* 0.000

*p > 0.0001 (Highly significant)

Irrespective of the retreatment file used, the retrievability of the sealer for groups I and II was significantly better compared to group III, with a significant difference (p < 0.05). However, on comparing the retrievability between group I and group II, it was found that there wasn’t any significant (p > 0.05) difference. On comparing the retrievability of sealers using different file systems, it was observed that R-Endo had better removal efficiency than Mani GPR, with a statistically significant difference between them (p < 0.05).

DISCUSSION

Nonsurgical retreatment aims to eradicate the persistent bacterial biofilms that cause periapical inflammation, thus creating an environment helpful for healing. To achieve comprehensive disinfection, complete removal of the present filling material along with meticulous chemical irrigation is imperative.9 Gutta-percha, when paired with a sealer, is considered an ideal material for obturation of the root canal because of its excellent biocompatibility, lack of toxicity, and easy retrievability.10 However, during retreatment, these root-filling materials act as a physical obstruction, preventing the irrigation solutions and instruments from effectively contacting the walls of the root canal, thereby opposing the removal of dead tissues and leftover bacteria. Completely removing the existing intracanal filling material is a complex but essential task, as it is necessary to address existing deficiencies or iatrogenic defects, if present,11 while simultaneously ensuring adequate disinfection before sealing all access points.12

In the current study, the null hypothesis was rejected as it showed a significant difference in the retrievability of CeraSeal, Bioceramic Sealer, and AH Plus when retrieved with two varying retreatment file systems, namely R-Endo and GPR.

Numerous techniques have been employed to assess the efficacy of different methods and instruments in cleaning and removing the obturating materials from the root canal system. In this study, CBCT imaging was used as it is a nondestructive technique for analyzing the geometry of the canal and the effectiveness of shaping methods by overlaying preinstrumentation and postinstrumentation images. It generates very thin sections and provides a true three-dimensional reconstruction of the object with isotropic resolution and cubic voxels.13

The results of the current study demonstrated that it was impossible to completely remove the root filling materials from the canal system. This is consistent with previous studies done by Baranwal et al.,7 Oltra et al.,14,15 and Hess et al.16 In this study, CSBS showed significantly better retrievability in comparison to epoxy resin-based sealers. This observation also corroborates the clinically oriented findings by Neelakantan et al.1 and Donnermeyer et al.4 This may be attributed to the creep capacity and extended polymerization time of AH Plus Sealer, which enables it to effectively penetrate micro-irregularities, forming a strong adhesive bond to dentin.17 Donnermeyer et al.4 explained in their study that the micromechanical interaction forms tag-like structures between the root canal wall and the CSBS, and along with the chemical reaction within the “mineral infiltration zone,” it creates a weaker bond to the dentin compared to the covalent bonds formed between the amino groups of dentinal collagen and the epoxy resin sealer. The frequency of voids between the gutta-percha cone and CSBS was higher in comparison to the gutta-percha cone and AH Plus Sealer. This may be due to the hydrophobic nature of gutta-percha repelling the hydrophilic nature of CSBS, making it easier to retrieve.18

In contrast to the present study, Baranwal et al.7 and Oltra et al.14 demonstrated that the retrievability of CSBS was challenging due to its ability to interact with phosphate-containing fluid, producing a structure that has chemical and crystalline characteristics similar to those of both the tooth and bone apatite. This phenomenon is claimed to enhance its bond strength to dentin.

Among the two CSBS, there was no significant difference in their retrievability. This could be due to the similar composition and setting mechanism of the sealers. Although CeraSeal showed better resistance to dislodgment than Bioceramic Sealer, as it contains smaller round-shaped particles ranging in size from 0.3 to 68 µm, it provides a regular surface to probe into the dentinal tubules, further enhancing the sealing efficacy and strength of the material.19

When comparing the retrievability of sealers using different file systems, R-Endo demonstrated significantly better removal efficiency than GPR (p < 0.05). This is in accordance with the study done by Ashraf et al.20,21 and Mollo et al.22 The superior performance of R-Endo can be attributed to its design features, including three equally spaced cutting edges with a lesser core structure and its circumferential filling action.20,21 The R-Endo file system has an active cutting tip design, which facilitates the progression of the instrument through the gutta-percha and ensures thorough shaping with a crown-down approach.15,22,23 In contrast, GPR files feature a broad radial land and a neutral cutting angle, which diminishes their cutting efficiency and screw effect while enhancing abrasion.24

The strength of the current study lies in its focus on the usage of cone beam computed tomography (CBCT) as a diagnostic method, emphasizing its diagnostic value in the retreatability of two Bioceramic Sealers and Epoxy Resin Sealer with different file systems.

A limitation of this study is that, from a clinical perspective, the volume of root filling material retrieved may be less critical than the surface area cleaned from the canal walls, where intracanal microbes could persist. Consequently, further research using three-dimensional imaging methods is necessary to measure the surface area of the curved root canal walls.25 While laboratory-based studies focus on the technical aspects of root filling removal, their clinical significance remains unclear. Thus, future research is required to establish the connection between technical factors and clinical outcomes of the techniques employed.

CONCLUSION

Regardless of the file system used, none of the sealers tested were completely removed from the root canals. AH Plus showed a statistically significant difference compared to CeraSeal and Prashanti Bioceramic Sealer. Group I showed no significant difference from group II. The removal efficacy of root canal filling material varied statistically substantially between Prashanti R-Endo and Mani GPR, as well as AH Plus R-Endo and Mani GPR. In contrast, CeraSeal R-Endo showed no significant difference from Mani GPR.

REFERENCES

1. Neelakantan P, Grotra D, Sharma S. Retreatability of 2 mineral trioxide aggregate–based root canal sealers: a cone-beam computed tomography analysis. J Endod 2013;39:893. DOI: 10.1016/j.joen.2013.04.022

2. Al-Azzawi AKJ. The efficiency of ProTaper rotary retreatment files in the removal of two different root filling materials. Mustansiria Dent J 2018;8:237. DOI: 10.32828/mdj.v8i3.334

3. Kirthiga M, Thomas G, Jose S, et al. Antimicrobial efficacy of calcium silicate-based bioceramic sealers against Enterococcus faecalis and Staphylococcus aureus – an in vitro study. J Conserv Dent Endod 2024;27:737. DOI: 10.4103/JCDE.JCDE_215_24

4. Donnermeyer D, Dornseifer P, Schäfer E, et al. The push-out bond strength of calcium silicate-based endodontic sealers. Head Face Med 2018;14:13. DOI: 10.1186/s13005-018-0170-8

5. Donnermeyer D, Bunne C, Schäfer E, et al. Retreatability of three calcium silicate-containing sealers and one epoxy resin-based root canal sealer with four different root canal instruments. Clin Oral Investig 2018;22:811. DOI: 10.1007/s00784-017-2156-5

6. Alsubait S, Alhathlol N, Alqedairi A, et al. A micro-computed tomographic evaluation of retreatability of BioRoot RCS in comparison with AH Plus. Aust Endod J 2021;47:222. DOI: 10.1111/aej.12456

7. Baranwal HC, Mittal N, Garg R, et al. Comparative evaluation of retreatability of bioceramic sealer (BioRoot RCS) and epoxy resin (AH Plus) sealer with two different retreatment files: an in vitro study. J Conserv Dent JCD 2021;24:88–93. DOI: 10.4103/jcd.jcd_657_20

8. Khandeparkar ANS, de Ataide IN, Fernandes M. A cone-beam computed tomographic analysis of total dentin removed, canal transportation, and canal-centering ability following instrumentation with three different file systems: an in vitro study. J Conserv Dent Endod 2023;26:574. DOI: 10.4103/JCDE.JCDE_19_23

9. Agarwal D, Raghavendra SS. Cleaning efficacy and debris extrusion of supplementary file systems XP-endo Finisher and XP-endo Finisher R in endodontic retreatment. J Conserv Dent Endod 2024;27:498–502. DOI: 10.4103/JCDE.JCDE_90_24

10. Nouroloyouni A, Samadi V, Salem Milani A, et al. Single cone obturation versus cold lateral compaction techniques with bioceramic and resin sealers: quality of obturation and push-out bond strength. Int J Dent 2023;2023:e3427151. DOI: 10.1155/2023/3427151

11. Friedman S, Stabholz A, Tamse A. Endodontic retreatment case selection and technique. Part 3. Retreatment techniques. J Endod 1990;16:543. DOI: 10.1016/s0099-2399(07)80219-6

12. Azim AA, Wang HH, Tarrosh M, et al. Comparison between Single-file Rotary Systems: Part 1—Efficiency, Effectiveness, and Adverse Effects in Endodontic Retreatment. J Endod 2018;44:1720. DOI: 10.1016/j.joen.2018.07.022

13. Ali A, Saraf P, Kamatagi L, et al. Comparative assessment of canal transportation, dentin loss, and remaining root filling material by different retreatment files an in vitro cross-sectional study. Contemp Clin Dent 2021;12:14–20. DOI: 10.4103/ccd.ccd_31_20

14. Oltra E, Cox TC, LaCourse MR, et al. Retreatability of two endodontic sealers, EndoSequence BC Sealer and AH Plus: a micro-computed tomographic comparison. Restor Dent Endod 2017;42:19. DOI: 10.5395/rde.2017.42.1.19

15. Hassan HY, Hadhoud FM, Mandorah A. Retreatment of XP-endo Shaper and R-Endo files in curved root canals. BMC Oral Health 2023;23:38. DOI: 10.5395/rde.2017.42.1.19

16. Hess D, Solomon E, Spears R, et al. Retreatability of a Bioceramic Root Canal Sealing Material. J Endod 2011;37:1547. DOI: 10.1016/j.joen.2011.08.016

17. Verma A, Arora A, Taneja S. Comparative evaluation of dentinal tubule penetration and push-out bond strength of new injectable hydraulic calcium disilicate based root canal sealer: a single blinded in vitro study. J Oral Biol Craniofacial Res 2024;14:143. DOI: 10.1016/j.jobcr.2024.01.009

18. Al Akam H, Kim HC, Jeong JW. Retreatment strategies for cases containing calcium silicate-based root canal sealers: a comprehensive review. Dent J 2024;12:41. DOI: 10.3390/dj12020041

19. Assiry AA, Karobari MI, Lin GSS, et al. Microstructural and elemental characterization of root canal sealers using FTIR, SEM, and EDS analysis. Appl Sci 2023;13:4517. DOI: 10.3390/app13074517

20. Ashraf K, Noushad MC, Sebastian A, et al. Evaluation of efficacy of three different rotary systems in removal of gutta-percha from root canal during retreatment: an in vitro study. Int J Recent Sci Res 2019;10:25. DOI: 10.24327/ijrsr.2019.1006.3568

21. Gogulnath D, Rajan RM, Arathy G, et al. A comparative evaluation of the canal centering ability of three rotary nickel-titanium retreatment systems in the mesio-buccal canals of mandibular first molars using computed tomography. J Conserv Dent JCD 2015;18:310. DOI: 10.4103/0972-0707.159735

22. Mollo A, Botti G, Prinicipi Goldoni N, et al. Efficacy of two Ni-Ti systems and hand files for removing gutta-percha from root canals: retreatment X-ray evaluation. Int Endod J 2012;45:1–6. DOI: 10.1111/j.1365-2591.2011.01932.x

23. Garg A, Nagpal A, Shetty S, et al. Comparison of time required by D-RaCe, R-Endo and Mtwo instruments for retreatment: an in vitro study. J Clin Diagn Res 2015;9:ZC47. DOI: 10.7860/JCDR/2015/11100.5596

24. Alberto Rubino G, de Miranda Candeiro GT, Gonzales Freire L, et al. Micro-CT evaluation of gutta-percha removal by two retreatment systems. Iran Endod J 2018;13:221. DOI: 10.22037/iej.v13i2.18599

25. Ajina MA, Shah PK, Chong BS. Critical analysis of research methods and experimental models to study removal of root filling materials. Int Endod J 2022;55:119–152. DOI: 10.1111/iej.13650

________________________
© The Author(s). 2025 Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and non-commercial reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.