Assessment of Bacterial Sealing Ability of Two Different Bio-Ceramic Sealers in Single-Rooted Teeth Using Single Cone Obturation Technique: An In Vitro Study

Abstract

The long-term success of root canal treatment requires the prevention of bacterial leakage between canal walls and root canal obturation. In this study, we compared the leakage of Enterococcus faecalis in thirty single-rooted mandibular premolars divided into three groups. The roots in two experimental groups were obturated using a single-cone obturation technique with two different bio-ceramic sealers (MTA Fillapex and CeraSeal) while the roots in the conventional group were obturated using the lateral condensation technique with an epoxy resin sealer (AH Plus). A bacterial leakage test was carried out using a modified microbial leakage model. In the MTA Fillapex group, 30% of the specimens showed a positive sign for bacterial leakage, while 80% of samples in the CeraSeal group leaked. In the AH Plus group, 50% of specimens had bacterial leakage in the canals. The variation of the average number of days between the groups was not found to be significantly different. Taken together, bio-ceramic sealers with single-cone obturation demonstrated comparable results to the resin-based sealer with lateral condensation technique in terms of sealing efficiency against Enterococcus faecalis. Additionally, MTA Fillapex could provide a better sealing ability than CeraSeal bio-ceramic sealer.

1. Introduction

In endodontics, a successful treatment plan requires strict control to avoid bacterial leakage during root canal treatment (RCT). However, bacteria can still survive after chemo-mechanical procedures and root canal filling. The root canal system is considered a three-dimensional (3D) apparatus. It is composed of the main canal and many lateral canals with ramifications, isthmuses, loops, deltas, and dentinal tubules. Therefore, cleaning and shaping should be accomplished in a 3D manner to ensure the penetration of irrigants into all the pulp tissues and bacteria in the complex root anatomy [1]. In addition, endodontic infections are considered polymicrobial [2]. Recent studies revealed that the leading cause of endodontic treatment failure and persistent root canal infections is the presence of several bacterial species, prominently Enterococcus faecalis (E. faecalis) [3]. Infection may happen due to bacterial leakage through the gaps between the endodontic sealers and either the gutta-percha or the internal canal wall [4].

To tackle this issue, several types of sealers with multiple chemical compositions, such as calcium hydroxide, zinc oxide, glass ionomer, and resin sealers, are used nowadays in endodontics [5]. Resin-based sealers have been the most used sealers for many years due to their easy handling, good wettability, dentinal tubule-penetrating properties, and potential to form a monoblock between the filling material and dentinal wall. The monoblock phenomenon indicates the formation of a single cohesive bond between the core material, sealing agent, and root canal dentin [6]. However, if misused, they might have some shrinkage during setting and form voids, which might increase the possibility of microbial leakage [7,8].

Significant efforts were made to achieve successful RCT using the latest revolution in root canal-sealing materials. Bio-ceramic sealers were introduced and attracted many clinicians’ attention owing to their biocompatibility and alkaline pH. Bio-ceramic sealers are also considered bio-active and non-toxic [9]. An example of a bio-ceramic sealer is MTA Fillapex (Angelus, Londrina, Brazil). MTA Fillapex is characterized by a high flowability rate.

Moreover, MTA Fillapex permeates quickly through the lateral and accessory tooth canals as it has a minimal film thickness. Notably, MTA Fillapex includes salicylate resin in its chemical composition for its bio-compatible and antimicrobial properties [10]. Another clinical advantage of MTA Fillapex is its low solubility and expansion as well as its high radiopacity and cementum regeneration with good sealing [11]. The calcium ion (Ca²⁺)-releasing ability of MTA Fillapex is a useful tool that assists in tissue regeneration and healing processes. MTA Fillapex also has excellent antibacterial properties due to its high pH (9.5–10.4) [12]. Another example of a Ca²⁺ silicate bio-ceramic sealer is CeraSeal (META BIOMED, Cheongju, Korea). CeraSeal provides an antimicrobial effect and high bio-compatibility due to its high pH (12.73). In addition, it has an excellent radiopacity (8 mm Al), provides good sealing ability, and can be used with single cone obturation [13], which employs a single gutta-percha cone, while the sealer thickness inside the canal mainly depends on the adaptation of the single gutta-percha cone to the canal walls [14]. This technique has become more popular among practitioners owing to its ability to complete RCT in a short time and with good results [15].

Recent literature has reported on the sealing ability of the relatively new bio-ceramic sealers [16]. The main mechanism involves tricalcium silicate and dicalcium silicate particles which, when in contact with humidity, develop Ca²⁺ silicate and Ca²⁺ hydroxide needles in the hydrate phase, which slowly release Ca²⁺ and hydroxyl (OH⁻) ions in the presence of phosphate-containing fluids. This will allow the Ca²⁺-deficient apatite to precipitate via the establishment of an initial amorphous Ca²⁺ phosphate [16,17,18]. Additionally, Ca²⁺ silicate hydrates release OH⁻ and Ca²⁺ ions, when in contact with human fluids that contain phosphates, which results in the formation of hydroxyapatite [19].

The antimicrobial capabilities of sealers used in endodontics were examined in previous studies. Yet, little information was provided regarding the comparison of the MTA Fillapex and CeraSeal sealers and their sealing efficiency against E. faecalis. Consequently, the present study aimed to compare E. faecalis leakage in single-rooted teeth obturated with two different bio-ceramic sealers and single-cone techniques when compared to a resin-based sealer and lateral condensation technique.

2. Materials and Methods

2.1. Sample Preparation

The preparation of samples was performed according to Celikten et al. with slight modifications [20]. In our study, the criteria of the included teeth were teeth with closed apices and without any evidence of resorption, fractures, caries, previous endodontic treatment, or abnormal anatomy. Hence, any tooth that did not fulfill these criteria was excluded from the study. The teeth were stored in a 10% formalin solution for approximately two weeks before the beginning of the study for teeth preservation. Then, digital periapical radiographs were taken in facial and proximal views for each tooth to confirm the presence of a single straight canal. Each tooth was decoronated with a diamond fissure bur (final length: 14 mm ± 1) below the level of the cemento-enamel junction. Canal patency was confirmed by fitting size 10 and 15 K-files (Dentsply Maillefer, Ballaigues, Switzerland) to the apical foramen, and all teeth were sterilized in an autoclave [20].

The root canals were shaped with a sequence of ProTaper Gold NiTi Rotary Files (Dentsply Maillefer, Switzerland) using an X-Smart Endodontic Rotary Motor (Dentsply Sirona, NC, USA). The motor was set at 300 rpm and had a torque of 3/Nm (according to the manufacturer’s instructions). Glyde gel (Dentsply Maillefer) was used during root canal preparation. A glide path was accomplished with the ProGlider file (Dentsply Maillefer; 0.16/0.02) along the working length. Root canals were instrumented tothe WL using the following file sequence: SX (0.19/0.04), S1 (0.18/0.02), S2 (0.20/0.04), F1 (0.20/0.07), and F2 (0.25/0.08), respectively, according to the manufacturer’s recommendations. A patency K-file size of 10 was used between each rotary file. Sodium hypochlorite (NaOCL, 2.5%) was used as an irrigant with a syringe and a 25-gauge needle. To maintain the apical patency, a size 10 K-file was passed through the apex, and to remove the smear layer, the canal was rinsed with 3 mL of ethylenediaminetetraacetic acid (EDTA, 17%) (Produits Dentaires, SA, Vevey, Switzerland) for 1 min, followed by a final rinse with normal saline for 30 s. Finally, sterile paper points of size F2 (0.25 mm tip) were used to dry the canals before the obturation procedure [20,21].

All teeth were randomly divided into 3 groups, 2 experimental groups and 1 conventional group (n = 10). Gutta-percha (size F2) master cones (TiaDent Inc., Houston, TX, USA) were disinfected by NaOCL (2.5%) for one minute followed by ethyl alcohol (70%). The obturation procedure was performed in aseptic conditions. Sealer placement was standardized using a 1 mL syringe to dispense 0.05 mL of sealer inside each canal without any additional sealer usage [22]. In group 1, MTA Fillapex bio-ceramic (MF) sealer was used for obturation of the root canal using a single gutta-percha cone. In group 2, CeraSeal bio-ceramic (CE) sealer was used for obturation of the root canal, similar to the previous group. Group 3 is the conventional (CO) group in which AH Plus (Dentsply Maillefer, Ballaigues, Switzerland) was used for obturation using a finger spreader by the lateral condensation technique. Excess gutta-percha was removed using a heated plugger. All specimens were stored in an incubator in 100% humidity at 37 °C for 7 days to allow the complete setting of the sealers.

2.2. Bacterial Leakage Testing

The bacterial leakage model preparation and leakage test were performed according to the protocol by Yanpiset et al. [23]. Briefly, root surfaces in all tested groups were sealed with two layers of varnish, except the apical 2 mm. A cut microcentrifuge tube was used for each obturated root, approximately 5 mm of the root obtruded through the cut end, while nearly 9 mm was in the tube. A cyanoacrylate adhesive (3m Super Glue Gel, 3m Company, Maplewood, MN, USA) varnish was used to seal the gaps between the tube and the root, and an autoclave was implemented for sterilization. Brain heart infusion (BHI) broth (Difco Laboratories, Detroit, MI, USA) was sterilized in a glass bottle. The microcentrifuge tube was then placed into the glass bottle. Approximately 2 mm of the root tip was immersed in BHI broth using aseptic techniques (Figure 1). One assembled model was incubated for 24 h at 37 °C to affirm the sterile condition.

A reference strain of E. faecalis (ATCC 29212) was cultured on BHI agar plates, and isolated colonies were suspended in 3 mL BHI broth media and incubated overnight at 37 °C. The broth was adjusted to 0.5 McFarland (corresponding to 1 × 10⁸ CFU). The upper chamber was filled with 400 μL of E. faecalis broth and incubated at 37 °C. The viability of E. faecalis was supported by changing the culture media every 48 h under aseptic conditions. The bacterial leakage was checked every 24 h by monitoring any sign of turbidity over a period of 60 days. Gram staining and bacterial culture were carried out from turbid media to identify E. faecalis, and the time-to-leakage (days) was recorded and verified for each sample.

2.3. Scanning Electron Microscopy (SEM)

Two samples from each group were randomly selected and evaluated using SEM. Samples were sectioned horizontally into three parts with double-face diamond discs (KG Sorensen, Ind. Com. Ltd.a.; Barueri, Sao Paolo, Brazil) into coronal, middle, and apical parts, no polish was applied. After an initial room temperature fixation process using glutaraldehyde solution in a concentration of 2.5%, the sections from each root were dehydrated using ethanol in ascending concentrations. Afterward, the sections were coated with gold using a sputter coater following the mounting step on metallic stubs (Quorum, Q150R ES, Lewes, UK). In this study, an SEM instrument (Emcrafts, Gyeonggi-do, Korea) was used for the inspection of the sections at ×500, ×1000, and ×2000 magnifications. Samples were inspected blindly in a qualitative manner.

2.4. Statistical Analysis

Data were assembled, organized, and statistically analyzed using GraphPad Prism 5 software (GraphPad Software, Inc., La Jolla, CA, USA). In this study, the numerical values were displayed as arithmetic means ± the standard deviations (SDs). The normality of the data was checked using a Shapiro–Wilk test and significant results showed that the data were not normally distributed in MF and CO groups. Hence, the inferential analysis of the data by a non-parametric test was selected. To compare the variation of means between the groups, a Kruskal–Wallis test was utilized followed by Dunn’s post hoc test. All p-values less than 0.05 were considered statistically significant.

3. Results

The three tested groups showed different results of bacterial leakage, however, none of the groups prevented bacterial leakage completely. Table 1 shows the results of bacterial leakage for each group after exposure to E. faecalis over a period of 60 days and the average duration (days) until bacterial leakage. The lowest number of leaked samples was detected in the MTA Fillapex (MF) group (30%), while the highest numbers of leaked samples were detected in the CeraSeal bio-ceramic sealer (CE) group (80%) and the AH Plus (CO) group (50%). No significant difference was detected among the study groups (p = 0.0609).

The results of the average number of days until bacterial leakage are demonstrated in the survival curves of the three tested groups (Figure 2). The MTA Fillapex (MF) group had an average of 47 days (SD = 20.9) and showed the longest time until bacterial leakage. The CeraSeal bio-ceramic sealer (CE) group showed the fewest number of days until bacterial leakage among all groups with an average of 25.3 days (SD = 20.3). The AH Plus (CO) group had an average score of 45 days (SD = 20.9).

The SEM micrographs revealed the sealer gaps among the tested groups from a qualitative analysis of the bacterial leakage after 60 days. The MTA Fillapex bio-ceramic sealer (MF) with the single-cone technique had a better adaptation to the root canal wall as shown in Figure 3A–C. This was followed by the AH Plus sealer (CO) with the lateral condensation techniques shown in Figure 3G–I. Finally, the CeraSeal bio-ceramic sealer (CE) with the single-cone technique showed the least adaptation to the root canal wall at the sealer–dentin interface, as shown in Figure 3D–F.

4. Discussion

One of the most common causes of endodontic therapy failures is bacterial leakage and ineffective eradication of microorganisms from the root canal system. Many variables could affect the leakage, such as the obturation techniques, the properties of the sealer, and the presence of a smear layer [24]. However, complete bacterial removal is not always feasible. Complete sealing is necessary to avoid the entrance of microorganisms from the oral cavity into the root canal system. During obturation, sealers are used to fill the spaces between the core material and the dentin wall. Moreover, they fill lateral canals and/or any canal irregularities [25]. Bio-ceramic sealers have potential importance in clinical practice due to their sealing ability, biocompatibility, hydrophilic nature, antibacterial property, bio-activity, and easy delivery which enhance their promising characteristics in the endodontic field.

The bacterial leakage model method was used in this study to evaluate and compare the sealability of two bio-ceramic sealers: MTA Fillapex and CeraSeal, using the single-cone technique and comparing them with the conventional resin sealer AH Plus while using the lateral condensation technique as a benchmark. The results showed that there were several differences in the percentage of samples with no leakage. Within the limitations of this technique [26], our study reported that the CeraSeal group had the highest number of leaked samples (80%) followed by the AH Plus group (50%), and the MTA Fillapex group had the least amount of non-leaked samples (30%). However, no significant difference was detected among the tested groups.

The better sealing ability of MTA Fillapex sealer may be due to its high flow rate (27 mm) and low film thickness, so it easily penetrated the lateral and accessory canals, regardless of the obturation technique or obturation temperature. Moreover, MTA Fillapex has excellent antibacterial properties due to the high pH (9.5–10.4) for extended antibacterial action and the tendency toward keeping the Ca²⁺ release relatively constant for up to 14 days. Moreover, MTA Fillapex has an extremely low solubility (0.1%) that prevents its erosion with time unlike the other sealers [27]. MTA Fillapex can expand and boost its sealing performance over time, especially if 17% EDTA was used as a final irrigant, as it helps the smear layer fuse to the MTA Fillapex sealer mass and adds volume to the sealer that will penetrate the dentinal tubules [28]. In addition, during the setting reaction of MTA Fillapex, it hydrates inorganic oxide components, which creates Ca²⁺ hydroxide and Ca²⁺ hydrate phases, forming a covalent bond with the amino group, which results in the expansion of the sealer and improves the overall sealing ability [29,30,31].

Furthermore, previous studies showed that bio-ceramic sealers do not shrink during the setting process since they do not contain any monomers, providing a good seal between the sealer and the canal walls [32]. These findings worked with Asawaworarit et al. [33], who concluded that MTA Fillapex showed fewer leaked samples when compared with AH Plus over a period of 60 days, although there is no significant difference among the groups. This was confirmed by SEM photographs, which found more adaptation of MTA Fillapex to the root canal wall under all magnifications.

AH Plus is an epoxy resin sealer with proper flowability and viscosity, which may help provide a higher degree of penetration. It etches the dentinal surface, exposes collagens, and results in a more efficient attachment to the dentinal walls [34]. Remy et al. [35] compared the marginal matching of MTA Fillapex, AH Plus, and Endofill. They showed that the greatest marginal matching capacity was shown with AH Plus, followed by Endofill and MTA Fillapex. The lowest microleakage of the AH Plus sealer may be due to its better marginal matching, better tubular penetration, and weak acidity [36,37].

The difference between our study and that of Remy et al. [35] may be due to the results provided by Rifaat et al. [28], who stated that the best bond strength can be achieved by using 7% maleic acid as the final irrigant for the best bonding results with AH Plus sealer, while the final irrigant in our study was EDTA, which was proven by Rifaat et al. [28] to give the best bonding results with MTA-based sealers. AH Plus has superior penetration into the micro irregularities that increases the mechanical interlocking between the dentin and the sealer because of its great capacity to creep and the long setting time unlike other bio-ceramic sealers which creates a chemo-mechanical bond with the root dentin [35,36,37,38]. That may be because of the hydrophobicity and the likelihood of shrinkage for AH Plus. The gutta-percha/AH Plus sealer interface is highly hydrophobic [39,40], and while the dentin is hydrophilic, the dentin/sealer interface is rather hydrophilic, creating gaps that act as major pathways of leakage. This was confirmed by SEM photographs which showed the adaptation of AH Plus sealer to the root canal wall under all magnifications when used with the lateral condensation technique.

Previous studies showed that the dentin–sealer gaps with bio-ceramic sealers are smaller than those with epoxy resin-based sealers. Properties such as shrinkage resistance, insolubility in the oral fluids, and hydrophilicity can help in gap formation reduction with bio-ceramic sealers. Attributable to the features and composition of bio-ceramic sealers, they can also produce Ca²⁺ hydroxide and hydroxyapatite, which can ensure an excellent bond to both the dentinal walls and the obturating core material [41,42]. Therefore, voids act as a reservoir for the bacteria and microorganisms, resulting in microleakage and jeopardizing the long-term success rate of root canal treatment.

CeraSeal is a premixed Ca²⁺ silicate-based sealer. According to the manufacturer, this sealer consists of Ca²⁺ silicates, zirconium oxide, and thickening agent and has a superior antimicrobial effect and high volumetric stability. It is claimed that it can be used with single-cone obturation due to expansion and hermetic sealing [43]. Surprisingly, although CeraSeal is a Ca²⁺ silicate-based bio-ceramic sealer, in the present study, 80% of the samples leaked over a period of 60 days. However, although this group had the most leaked samples, we must keep in mind that only two samples leaked within the first 7 days. This result may be due to the washout effect of the sealer. The washout effect is a phenomenon in which the resistance to the outflow decreases with the volume flowing through it [44]. This was confirmed by SEM photographs, which showed the least adaptation of CeraSeal sealer to the root canal wall under all magnifications when used with the single-cone technique.

Portland cement is the major component of MTA. It is used as a binder in concrete. Ca²⁺ silicate-based cements (the main component of the Portland cement in MTA) exhibit an increase in washout resistance after adding carboxymethyl chitosan or gelatin to their components [40]. The manufacturer added a thickening agent to the CeraSeal sealer to improve the washout effect of the sealer. Moreover, the Ca²⁺ silicate produces Ca²⁺ silicate hydrate gel and Ca²⁺ aluminate hydrate gel by absorbing the moisture from all the surrounding tissues in the root canal system and some crystallization of Ca²⁺ hydroxide according to the manufacturer. All these factors may contribute to CeraSeal sealer’s increased viscosity and decreased flowability. Currently, it is well understood that the differences in the format, filler content, and/or thickening agents may cause differences in physical and chemical properties as well [45]. Hence, its samples showed the highest number of leakages in our study.

Several factors, including the physical properties of the materials (such as film thickness, wettability, and flowability), the anatomical variations of the root canal system, and the obturation technique, might affect the degree of microleakage [46,47]. The obturation techniques used in this study were the single-cone technique with the bio-ceramic sealers and the lateral condensation technique with the AH Plus sealer. Bio-ceramic sealers are advised to be used with a heat-free obturation technique to avoid them hardening quickly. This was tested by Abdellatif et al. who used a modified obturation technique with bio-ceramic sealers and revealed that a greater penetration into the dentinal tubules is associated with the non-heating of the apical area using this new technique [48].

Neither technique can provide obturation free of voids [49]. Elshinawy et al. [50] recommended the usage of bio-ceramic sealers with a single-cone technique due to the slow setting time of the bio-ceramic sealers, which may allow more time for expansion, hence pushing the sealer toward the dentinal walls of the root. That may accentuate the single cone obturation technique’s superior sealability. This was confirmed by SEM results of the adaptation of AH Plus sealer to the root canal wall.

More studies [51,52] found that bio-ceramic sealers ended up with smaller gaps than epoxy resin-based sealers. Hydrophilicity, insolubility, and unshrinkable nature in oral fluids can help in producing fewer and smaller gaps with bio-ceramic sealers. The inherent compositional properties of bio-ceramic sealers produce Ca²⁺ hydroxide and hydroxyapatite, guaranteeing an outstanding bond between the sealer and both the dentin walls and the filling material. The AH Plus sealer, however, achieved the highest bonding strength results with cold lateral compaction compared with the single-cone technique [53]. This may be explained by the pressure provided by the spreaders over the master and accessory cones. It can create lateral and apical forces and can help the sealer interlock with the dentinal tubules and/or irregularities. On the other hand, the single-cone technique generates mainly apical forces. This was confirmed by SEM results with the least adaptation of CeraSeal sealer to the root canal wall.

Wang et al. [54] stated that regardless of the kinds of sealer or obturation techniques used, the penetration of dentinal tubules of the root canal increased in the apico-coronal direction due to the increased removal of the smear layer in the upper-middle part of the root canal. In fact, the degree of sealer adhesion to the dentinal walls depends on the dentin surface energy, surface tension and wettability of the sealer, and the cleanliness of the dentin surface.

Hence, the different results in our study may be due to the different materials, different obturation techniques, or the anatomical variations of the root samples used. Future studies should include larger samples and reproducible methodologies to ensure the same results.

5. Conclusions

Within the limitations of this study, bio-ceramic sealers with single-cone obturation showed comparable results to the resin-based sealer with the lateral condensation technique in terms of sealing efficiency against E. faecalis. In addition, MTA Fillapex bio-ceramic sealer could provide a better sealing ability than CeraSeal bio-ceramic sealer.

Author Contributions

Conceptualization, A.A. (Abbas AlHamali), A.A. (Abdullh AlQasser) and D.M.A.; methodology, A.M.R., A.A. (Abbas AlHamali), H.M.A. (Hussain M. AlHussain) and A.A. (Abdullh AlQasser); validation, H.M.A. (Hatem M. Abuohashish) and S.R.; resources, Z.A., H.M.A. (Hussain M. AlShoalah), A.A. (Abbas AlHamali) and A.A. (Abdullh AlQasser); data curation, H.M.A. (Hussain M. AlShoalah), A.K., H.M.A. (Hussain M. AlHussain) and Z.A.; supervision, D.M.A. and A.M.R.; writing—original draft preparation, A.K. and H.M.A. (Hussain M. AlHussain); writing—review and editing, D.M.A., A.M.R., H.M.A. (Hatem M. Abuohashish) and S.R. All authors have read and agreed to the published version of the manuscript.

Institutional Review Board Statement

The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board at Imam Abdulrahman bin Faisal University (IRB-2022-02-210, date of approval 29 May 2022).

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

Data and materials have been provided in the main manuscript and, where necessary, additional information of the study can be made available by the corresponding author upon reasonable request.

Acknowledgments

The authors would like to thank Soban Qadir Khan for his valuable support.

Conflicts of Interest

The authors declare no conflict of interest.

Footnotes

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Figures and Table

Figure 1. Modified bacterial leakage test model.

Figure 2. (A) The survival curves of the 3 tested groups expressed in the number of incubation days before bacterial leakage. (B) A scattered dot plot for the average days till the bacterial leakage in each sample in all groups. The dotted line represents the mean of each group and error bars represent the SD (MF: MTA Fillapex, CE: CeraSeal bio-ceramic sealer, CO: AH Plus).

Figure 3. Scanning electron microscope micrographs after 60 days showing the sealer/dentin interface at magnifications of ×500, ×1000, and ×2000, respectively, for the tested groups. (A–C) Different magnifications of the MF group showing MTA Fillapex with the best adaptation at the root canal dentin-sealer interface (blue arrows). (D–F) Different magnifications of the CE group showing CeraSeal bio-ceramic sealer with marked interfacial gaps at the root canal dentinal wall/sealer interface (blue arrows). (G–I) Different magnifications of the CO group showing AH Plus with good adaptation with minor interfacial gaps at the root canal dentinal wall/sealer interface (blue arrows).

Table 1

The results of bacterial leakage over a period of 60 days and the average duration (days) until bacterial leakage.

Group	Percentage of Leaked Samples (%)	Average Days (SD)	p-Value
MTA Fillapex (MF)	30%	47.0 (20.9)	0.0609
CeraSeal sealer (CE)	80%	25.9 (20.3)
AH Plus (CO)	50%	45.2 (20.9)

References

1. Iandolo, A.; Dagna, A.; Poggio, C.; Capar, I.; Amato, A.; Abdellatif, D. Evaluation of the actual chlorine concentration and the required time for pulp dissolution using different sodium hypochlorite irrigating solutions. J. Conserv. Dent.; 2019; 22, 108. [DOI: https://dx.doi.org/10.4103/JCD.JCD_165_19] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/31142977]

2. Mattigatti, S.; Ratnakar, P.; Moturi, S.; Varma, S.; Rairam, S. Antimicrobial effect of conventional root canal medicaments vs propolis against Enterococcus faecalis, Staphylococcus aureus and Candida albicans. J. Contemp. Dent. Pract.; 2012; 13, pp. 305-309. [DOI: https://dx.doi.org/10.5005/jp-journals-10024-1142] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/22918001]

3. Alghamdi, F.; Shakir, M. The influence of Enterococcus faecalis as a dental root canal pathogen on endodontic treatment: A systematic review. Cureus; 2020; 12, e7257. [DOI: https://dx.doi.org/10.7759/cureus.7257] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/32292671]

4. Hovland, E.J.; Dumsha, T.C. Leakage evaluation in vitro of the root canal sealer cement Sealapex. Int. Endod. J.; 1985; 18, pp. 179-182. [DOI: https://dx.doi.org/10.1111/j.1365-2591.1985.tb00437.x]

5. Mangat, P.; Dhingra, A.; Muni, S.; Bhullar, H.K. To compare and evaluate the antimicrobial activity of three different root canal sealers: An In Vitro Study. J. Conserv. Dent. JCD; 2020; 23, 571. [DOI: https://dx.doi.org/10.4103/JCD.JCD_610_20]

6. Fisher, M.A.; Berzins, D.W.; Bahcall, J.K. An In Vitro Comparison of Bond Strength of Various Obturation Materials to Root Canal Dentin Using a Push-Out Test Design. J. Endod.; 2007; 33, pp. 856-858. [DOI: https://dx.doi.org/10.1016/j.joen.2007.02.011]

7. Phukan, A.H.; Mathur, S.; Sandhu, M.; Sachdev, V. The effect of different root canal sealers on the fracture resistance of endodontically treated teeth-in vitro study. Dent. Res. J.; 2017; 14, 382. [DOI: https://dx.doi.org/10.4103/1735-3327.218558]

8. Munitić, M.Š.; Budimir, A.; Jakovljević, S.; Anić, I.; Bago, I. Short-term antibacterial efficacy of three bioceramic root canal sealers against Enterococcus faecalis biofilms. Acta Stomatol. Croat.; 2020; 54, 3. [DOI: https://dx.doi.org/10.15644/asc54/1/1]

9. Mutal, L.; Gani, O. Presence of pores and vacuoles in set endodontic sealers. Int. Endod. J.; 2005; 38, pp. 690-696. [DOI: https://dx.doi.org/10.1111/j.1365-2591.2005.00988.x]

10. Angelus^® MTA Fillapex Bioceramic Root Canal Sealer. Clinical Research Dental, 2021. Available online: https://www.clinicalresearchdental.com/products/angelus-mta-fillapex-bioceramic-root-canal-sealer?variant=30038573219904 (accessed on 25 August 2021).

11. Sagsen, B.; Ustün, Y.; Demirbuga, S.; Pala, K. Push-out bond strength of two new calcium silicate-based endodontic sealers to root canal dentine. Int. Endod. J.; 2011; 44, pp. 1088-1091. [DOI: https://dx.doi.org/10.1111/j.1365-2591.2011.01925.x]

12. MTA Fillapex—Endodontic Sealer. Scientific Profile. Available online: https://www.clinicalresearchdental.com/marketing/mta%20fillapex%20-%20scientific%20profile_medium.pdf (accessed on 25 August 2021).

13. CeraSeal BioCeramic Sealer. Available online: https://www.meta-europe.com/en/produkt/ceraseal/l (accessed on 25 August 2021).

14. Economides, N.; Kokorikos, I.; Kolokouris, I.; Panagiotis, B.; Gogos, C. Comparative study of apical sealing ability of a new resin-based root canal sealer. J. Endod.; 2004; 30, pp. 403-405. [DOI: https://dx.doi.org/10.1097/00004770-200406000-00006] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/15167466]

15. Pereira, A.C.; Nishiyama, C.K.; de Castro Pinto, L. Single-cone obturation technique: A literature review. RSBO Rev. Sul-Bras. Odontol.; 2012; 9, pp. 442-447.

16. Pontoriero, D.I.; Cagidiaco, E.F.; Cardinali, F.; Fornara, R.; Amato, M.; Grandini, S.; Ferrari, M. Sealing ability of two bioceramic sealers used in combination with three obturation techniques. J. Osseointegr.; 2022; 14, pp. 143-148.

17. Prati, C.; Gandolfi, M.G. Calcium silicate bioactive cements: Biological perspectives and clinical applications. Dent. Mater.; 2015; 31, pp. 351-370. [DOI: https://dx.doi.org/10.1016/j.dental.2015.01.004]

18. Tay, F.R.; Pashley, D.H. Guided tissue remineralisation of partially demineralised human dentine. Biomaterials; 2008; 29, pp. 1127-1137. [DOI: https://dx.doi.org/10.1016/j.biomaterials.2007.11.001]

19. Yamamoto, S.; Han, L.; Noiri, Y.; Okiji, T. Evaluation of the Ca ion release, pH and surface apatite formation of a prototype tricalcium silicate cement. Int. Endod. J.; 2017; 50, pp. e73-e82. [DOI: https://dx.doi.org/10.1111/iej.12737]

20. Celikten, B.; Uzuntas, C.F.; Orhan, A.I.; Orhan, K.; Tufenkci, P.; Kursun, S.; Demiralp, K.Ö. Evaluation of root canal sealer filling quality using a single-cone technique in oval shaped canals: An In vitro Micro-CT study. Scanning; 2016; 38, pp. 133-410. [DOI: https://dx.doi.org/10.1002/sca.21249]

21. Mohamed El Sayed, M.A.A.; Al Husseini, H. Apical dye leakage of two single-cone root canal core materials (hydrophilic core material and gutta-percha) sealed by different types of endodontic sealers: An in vitro study. J. Conserv. Dent.; 2018; 21, pp. 147-152. [DOI: https://dx.doi.org/10.4103/JCD.JCD_154_17]

22. Dash, A.K.; Dash, A.; Bendre, A.; Farista, S.; Farista, S. Comparison of Three Different Sealer Placement Techniques: An In vitro Confocal Laser Microscopic Study. Contemp. Clin. Dent.; 2017; 8, 310. [DOI: https://dx.doi.org/10.4103/CCD.CCD_1109_16]

23. Yanpiset, K.; Banomyong, D.; Chotvorrarak, K.; Srisatjaluk, R.L. Bacterial leakage and micro-computed tomography evaluation in round-shaped canals obturated with bioceramic cone and sealer using matched single cone technique. Restor. Dent. Endod.; 2018; 43, e30. [DOI: https://dx.doi.org/10.5395/rde.2018.43.e30]

24. Guerisoli, D.M.; Marchesan, M.A.; Walmsley, A.D.; Lumley, P.J.; Pecora, J.D. Evaluation of smear layer removal by EDTAC and sodium hypochlorite with ultrasonic agitation. Int. Endod. J.; 2002; 35, pp. 418-421. [DOI: https://dx.doi.org/10.1046/j.1365-2591.2002.00488.x]

25. Schwartzer, E.; Genari, B.; Collares, F.M.; Leitune, V.C.; Ogliari, F.A.; Samuel, S.M. Bismuth subsalicylate as filler particle for an experimental epoxy-based root canal sealer. Braz. J. Oral Sci.; 2013; 12, pp. 173-177. [DOI: https://dx.doi.org/10.1590/S1677-32252013000300005]

26. Rechenberg, D.K.; De-Deus, G.; Zehnder, M. Potential systematic error in laboratory experiments on microbial leakage through filled root canals: Review of published articles. Int. Endod. J.; 2011; 44, pp. 183-194. [DOI: https://dx.doi.org/10.1111/j.1365-2591.2010.01821.x] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/21219357]

27. Rawtiya, M.; Verma, K.; Singh, S.; Munuga, S.; Khan, S. MTA-based root canal sealers. J. Orofac. Res.; 2013; 3, pp. 16-21. [DOI: https://dx.doi.org/10.5005/jp-journals-10026-1057]

28. Rifaat, S.; Rahoma, A.; Alkhalifa, F.; AlQuraini, G.; Alsalman, Z.; Alwesaibi, Z.; Taymour, N. Push-Out Bond Strength of EndoSeal Mineral Trioxide Aggregate and AH Plus Sealers after Using Three Different Irrigation Protocols. Eur. J. Dent.; 2023; 17, pp. 76-81. [DOI: https://dx.doi.org/10.1055/s-0041-1742128] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/35196723]

29. Jafari, F.; Sobhani, E.; Samadi-Kafil, H.; Pirzadeh, A.; Jafari, S. In vitro evaluation of the sealing ability of three newly developed root canal sealers: A bacterial microleakage study. J. Clin. Exp. Dent.; 2016; 8, pp. e561-e565. [DOI: https://dx.doi.org/10.4317/jced.52992]

30. Camilleri, J. Hydration mechanisms of mineral trioxide aggregate. Int. Endod. J.; 2007; 40, pp. 462-470. [DOI: https://dx.doi.org/10.1111/j.1365-2591.2007.01248.x] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/17459120]

31. Storm, B.; Eichmiller, F.C.; Tordik, P.A.; Goodell, G.G. Setting expansion of gray and white mineral trioxide aggregate and Portland cement. J. Endod.; 2008; 34, pp. 80-82. [DOI: https://dx.doi.org/10.1016/j.joen.2007.10.006] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/18155499]

32. Trope, M.; Bunes, A.; Debelian, G. Root filling materials and techniques: Bioceramics a new hope?. Endod. Top.; 2015; 32, pp. 86-96. [DOI: https://dx.doi.org/10.1111/etp.12074]

33. Asawaworarit, W.; Yachor, P.; Kijsamanmith, K.; Vongsavan, N. Comparison of the Apical Sealing Ability of Calcium Silicate-Based Sealer and Resin-Based Sealer Using the Fluid-Filtration Technique. Med. Princ. Pract.; 2016; 25, pp. 561-565. [DOI: https://dx.doi.org/10.1159/000450577]

34. Nunes, V.H.; Silva, R.G.; Alfredo, E.; Sousa-Neto, M.D.; Silva-Sousa, Y.T. Adhesion of Epiphany and AH Plus sealers to human root dentin treated with different solutions. Braz. Dent. J.; 2008; 19, pp. 46-50. [DOI: https://dx.doi.org/10.1590/S0103-64402008000100008] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/18438559]

35. Remy, V.; Krishnan, V.; Job, T.V.; Ravisankar, M.S.; Raj, C.V.R.; John, S. Assessment of Marginal Adaptation and Sealing Ability of Root Canal Sealers: An in vitro Study. J. Contemp. Dent. Pract.; 2017; 18, pp. 1130-1134. [DOI: https://dx.doi.org/10.5005/jp-journals-10024-2188] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/29208787]

36. Matloff, I.R.; Jensen, J.R.; Singer, L.; Tabibi, A. A comparison of methods used in root canal sealability studies. Oral Surg. Oral Med. Oral Pathol.; 1982; 53, pp. 203-208. [DOI: https://dx.doi.org/10.1016/0030-4220(82)90288-2]

37. Moradi, S.; Naghavi, N.; Rohani, E.; Javidi, M. Evaluation of microleakage following application of a dentin bonding agent as root canal sealer in the presence or absence of smear layer. J. Oral Sci.; 2009; 51, pp. 207-213. [DOI: https://dx.doi.org/10.2334/josnusd.51.207] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/19550088]

38. Inan, U.; Aydin, C.; Tunca, Y.M.; Basak, F. In vitro evaluation of matched-taper single-cone obturation with a fluid filtration method. J. Can. Dent. Assoc.; 2009; 75, 123. [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/19267963]

39. Gandolfi, M.G.; Siboni, F.; Prati, C. Properties of a novel polysiloxane-guttapercha calcium silicate-bioglass-containing root canal sealer. Dent. Mater.; 2016; 32, pp. e113-e126. [DOI: https://dx.doi.org/10.1016/j.dental.2016.03.001]

40. Hegde, V.; Arora, S. Sealing ability of a novel hydrophilic vs. conventional hydrophobic obturation systems: A bacterial leakage study. J. Conserv. Dent.; 2015; 18, pp. 62-65. [DOI: https://dx.doi.org/10.4103/0972-0707.148898]

41. Rekha, R.; Kavitha, R.; Venkitachalam, R.; Prabath, S.V.; Deepthy, S.; Krishnan, V. Comparison of the sealing ability of bioceramic sealer against epoxy resin based sealer: A systematic review & meta-analysis. J. Oral Biol. Craniofac. Res.; 2023; 13, pp. 28-35. [DOI: https://dx.doi.org/10.1016/j.jobcr.2022.10.006]

42. Mohammadian, F.; Farahanimastary, F.; Dibaji, F.; Kharazifard, M.J. Scanning Electron Microscopic Evaluation of the Sealer-Dentine Interface of Three Sealers. Iran. Endod. J.; 2017; 12, pp. 38-42. [DOI: https://dx.doi.org/10.22037/iej.2017.08]

43. Kharouf, N.; Arntz, Y.; Eid, A.; Zghal, J.; Sauro, S.; Haikel, Y.; Mancino, D. Physicochemical and Antibacterial Properties of Novel, Premixed Calcium Silicate-Based Sealer Compared to Powder-Liquid Bioceramic Sealer. J. Clin. Med.; 2020; 9, 3096. [DOI: https://dx.doi.org/10.3390/jcm9103096]

44. Formosa, L.M.; Mallia, B.; Camilleri, J. Mineral trioxide aggregate with anti-washout gel-properties and microstructure. Dent. Mater.; 2013; 29, pp. 294-306. [DOI: https://dx.doi.org/10.1016/j.dental.2012.11.009] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/23253552]

45. Muedra, P.; Forner, L.; Lozano, A.; Sanz, J.L.; Rodríguez-Lozano, F.J.; Guerrero-Gironés, J.; Riccitiello, F.; Spagnuolo, G.; Llena, C. Could the Calcium Silicate-Based Sealer Presentation Form Influence Dentinal Sealing? An In Vitro Confocal Laser Study on Tubular Penetration. Materials; 2021; 14, 659. [DOI: https://dx.doi.org/10.3390/ma14030659] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/33572611]

46. Parirokh, M.; Torabinejad, M. Mineral trioxide aggregate: A comprehensive literature review--Part III: Clinical applications, drawbacks, and mechanism of action. J. Endod.; 2010; 36, pp. 400-413. [DOI: https://dx.doi.org/10.1016/j.joen.2009.09.009]

47. Sfeir, G.; Zogheib, C.; Patel, S.; Giraud, T.; Nagendrababu, V.; Bukiet, F. Calcium Silicate-Based Root Canal Sealers: A Narrative Review and Clinical Perspectives. Materials; 2021; 14, 3965. [DOI: https://dx.doi.org/10.3390/ma14143965] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/34300886]

48. Abdellatif, D.; Amato, A.; Calapaj, M.; Pisano, M.; Iandolo, A. A novel modified obturation technique using biosealers: An ex vivo study. J. Conserv. Dent.; 2021; 24, 369. [DOI: https://dx.doi.org/10.4103/JCD.JCD_142_21] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/35282581]

49. Bhandi, S.; Mashyakhy, M.; Abumelha, A.; Alkahtany, M.; Jamal, M.; Chohan, H.; Raj, A.; Testarelli, L.; Reda, R.; Patil, S. Complete Obturation-Cold Lateral Condensation vs. Thermoplastic Techniques: A Systematic Review of Micro-CT Studies. Materials; 2021; 14, 4013. [DOI: https://dx.doi.org/10.3390/ma14144013]

50. Elshinawy, M.I.; Abdelaziz, K.M.; Khawshhal, A.A.; Alqisi, A.Y.; Al-Shari, H.H.; Alsalhi, I.Y. Sealing ability of two adhesive sealers in root canals prepared with different rotary file systems. Tanta Dent. J.; 2019; 16, 21.

51. Hegde, V.R.; Arora, N.J. Dentinal element incorporation, interfacial adaptation, and pH change induced by bioceramic sealer, mineral trioxide aggregate-based sealer, and epoxy resin-based sealer–An in vitro, scanning electron microscopy electron probe X-ray microanalysis study. Endodontology; 2020; 32, 76.

52. Gyulbenkiyan, E.; Gusiyska, A.; Vassileva, R.; Dyulgerova, E. Scanning electron microscopic evaluation of the sealer/dentine interface of two sealers using two protocols of irrigation. J. IMAB–Annu. Proceeding Sci. Pap.; 2020; 26, pp. 2887-2891. [DOI: https://dx.doi.org/10.5272/jimab.2020261.2887]

53. Rached-Junior, F.J.A.; Souza, A.M.; de Macedo, L.M.D.; Raucci-Neto, W.; Baratto-Filho, F.; Silva, B.M.; Silva-Sousa, Y.T.C. Effect of root canal filling techniques on the bond strength of epoxy resin-based sealers. Braz. Oral Res.; 2016; 30, S1806-83242016000100217. [DOI: https://dx.doi.org/10.1590/1807-3107BOR-2016.vol30.0024]

54. Wang, Y.; Liu, S.; Dong, Y. In vitro study of dentinal tubule penetration and filling quality of bioceramic sealer. PLoS ONE; 2018; 13, e0192248. [DOI: https://dx.doi.org/10.1371/journal.pone.0192248]