An effective root canal treatment is based on the total elimination of the microorganisms from the root canal system and the creation of a lasting three-dimensional seal, which prevents reinfection.[1] Although instrumentation and irrigation methods have improved in endodontics, the complexity of the root canal system may allow for the survival of microorganisms in the root canal system, making the quality of obturation a vital factor in successful long-term outcomes.[2] Sealers are important for filling irregularities, accessory canals and gutta-percha-dentinal wall interface, limiting microleakage and enhancing the obturation integrity.[3] A perfect root canal sealer should have good sealing properties, be dimensionally stable, have a low solubility, be biocompatible, be easy to flow, have radiopacity and remain active against microorganisms over time.[4]

Apical and coronal microleakage are still one of the most prevalent causes of failure of endodontic treatments.[5] Epidemiological studies have reported that, after root canal treatment, about 14-16% of the treated teeth would show persistent apical periodontitis, and poor obturation and leakage of the coronal seal have been reported as the main contributing factors.[6, 7] Root canal treatment treats over one billion teeth worldwide and endodontics is responsible for millions of dental visits each year.[8] Root canal therapy has a reported long-term success rate of 86% to 95%, when the cleaning, shaping and obturation of the canal is done properly.[9] However, if the root canal system is not adequately sealed, the risk of bacterial penetration, reinfection and treatment failure is significantly increased, making root canal sealers with better physicochemical properties a paramount consideration.[10]

The bioceramic sealers are a significant development in endodontic obturation materials.[11] These sealers are composed mainly of calcium silicate-based compounds and are hydrophilic because they rely on moisture within dentinal tubules to set.[12] They possess bioactive properties, including the release of calcium ions, promotion of hydroxyapatite formation, and the formation of an interfacial chemical bonding zone with dentin.[13] Apart from their excellent biocompatibility, bioceramic sealers also exhibit antibacterial activity due to their alkaline pH and can promote the healing of periapical tissues.[14] This prompted interest in their use as next-generation sealers for root canals.[14]

Sealing ability and solubility are two of the most important physicochemical properties of endodontic sealers that can be used to predict the performance of a sealer in the clinical setting.[15] Good sealing properties will provide limited bacterial penetration at the sealer-dentin interface, and low solubility will help the material to remain intact after extended contact with tissue fluids.[16] Over-dissolution of a sealer can cause voids, more microleakage, re-colonization of bacteria, and poorer treatment results.[17]

In addition, little is known about the behavior of endodontic materials from laboratory environments under climatic conditions, storage conditions, and clinical practice that are different from those found in the United States. Development of locally relevant evidence is important to inform the choice of sealer that has the best long-term performance, is cost-effective, and is clinically suitable. A direct comparison of bioceramic and resin-based sealers, using the same laboratory protocols for sealing ability and solubility, will provide much-needed evidence and help evidence-based decision-making in contemporary endodontic literature. So, the present in-vitro study aims to compare the sealing ability and solubility of two root canal sealers, bioceramic and resin-based sealers, under standard experimental conditions.

Comparative in vitro laboratory research was performed to assess and compare the sealing ability and solubility of bioceramic and resin-based root canal sealers under standard conditions. The study was carried out in Dental Materials Department. The study was conducted over a period of six months, from July to December, 2025 The sample size was determined from OpenEpi Version 3.01 based on the previous study by Silva et al., which compared the sealing performance of the bioceramic and epoxy resin-based sealers and showed a mean dye penetration of 1.21 ± 0.42 mm for the bioceramic sealer and 1.62 ± 0.51 mm for the resin-based sealer.[18] For a 95% confidence level, 80% study power, and an equal allocation ratio (1:1), the minimum sample size per group is 30 specimens with a total sample size of 60. A non-probability consecutive sampling technique was employed. The study involved freshly extracted human permanent single-rooted teeth with mature apices, straight root canals, intact root structure, and fully formed root structure. Eligible teeth were those removed for orthodontic, periodontal, or prosthodontic reasons. There were no previous endodontic treatments, root resorption, calcifications, developmental anomalies, fractures, cracks, or carious lesions reaching the root surface. To ensure standardization of specimens, teeth with multiple canals, curved roots with angles exceeding 20°, immature apices, external or internal resorption, previous restorations that involved the root, or microscopic structural defects were excluded from the study. All soft tissues and calculus that adhered to the teeth were removed with ultrasonic scalers and the teeth were disinfected by immersion in 0.1% thymol solution for 24 hours before they were stored in distilled water at room temperature until use. Standardized root lengths of 15 mm were obtained by decoronating the teeth at the cementoenamel junction using a water-cooled diamond disc. The size 10 K-file was used to establish canal patency, and the working length was determined by the point at which the file tip was seen at the apical foramen, minus 1 mm. Rotate the Nickel-Titanium file to prepare the biomechanics up to ProTaper Universal F3 as per the manufacturer's instructions. Irrigation was performed with 2.5% sodium hypochlorite after every file application, and a final irrigation with 17% EDTA for 1 minute was performed to remove the smear layer and a final irrigation with distilled water. The canals were then dried using sterile paper points. Prepped teeth were randomly divided into two groups, equal in size. Group A was obturated with gutta-percha and calcium silicate-based bioceramic sealer, while Group B was obturated with gutta-percha and an epoxy resin-based sealer (AH Plus) using a single-cone obturation technique. Temporary sealing of coronal access cavities was done with a heated instrument to remove excess gutta-percha. All specimens were stored at 100% RH and 37°C for 7 days to ensure complete setting of the sealers. The dye penetration method was used to assess sealing ability. Specimens were placed in the methylene blue dye solution for 72 hours, washed, and cut longitudinally with a diamond disc to expose the external surfaces of the roots except for the apical 2 mm. Two independent blinded examiners used a stereomicroscope at ×20 magnification to measure the linear dye penetration down the apex to the coronal aspect in millimeters. Two readings were taken and averaged for analysis. The solubility testing was carried out in ‘accordance with ISO 6876:2012’.[19] The standardized sealer disc was produced using a stainless steel mold, having a diameter of 20 mm ± 1 mm and a thickness of 1.5 mm ± 0.1 mm. Once set, the mass of each specimen was measured with an analytical balance capable of 0.0001g to determine the initial mass. The specimens were then placed in distilled water at 37°C for 24 hours. The data collected were entered and analyzed with IBM Statistical Package for Social Sciences (SPSS) version 26.0. The continuous variables (including dye penetration and percentage of solubility) were presented as mean ± SD values, and the categorical variables as frequencies and percentages where applicable. The normality of continuous variables was tested with the Shapiro–Wilk test. The data were assumed to be normally distributed; therefore, the independent samples t-test was used for comparisons among the two independent groups. Intraclass correlation coefficient (ICC) was used to determine the inter-observer agreement in the measurement of dye penetration. A p-value of ≤0.05 was considered statistically significant for all analyses.

A total of 60 extracted human permanent single-rooted teeth were included in the study and equally allocated into the bioceramic sealer group (n = 30) and the resin-based sealer group (n = 30). All specimens were subjected to the same preparation, including the same root length, working length, instrumentation of the canals, irrigation protocol, obturation technique, and storage conditions before being tested in the laboratory. There were no specimens dropped out of the experimental process and all of the samples were available for the final process. (Table 1).

The continuous outcome variables were found to be normally distributed, and hence parametric statistical tests were used. The samples obturated with the bioceramic sealer showed significantly less dye penetration than the resin-based sealer, which indicates greater sealer ability. In contrast, the percentage solubility of the resin-based sealer (less than 1%) was significantly lower compared to that of the bioceramic sealer, indicating greater dimensional stability after immersion. Independent samples t-tests determined that there were statistically significant differences between the two groups for both sealing ability and solubility. (Table 2).

Inter-observer reliability was determined and was found to be excellent between the two blinded examiners for the measurements of dye penetration. The intraclass correlation coefficient (ICC) showed very good consistency, indicating the reliability and repeatability of the measurement technique. The findings suggest there was low observer variability and that this was not likely to have affected the results of this study. (Table 3).

Table 1. Baseline Characteristics and Standardization of Experimental Specimens (n = 60)

Table 2. Comparative Evaluation of Sealing Ability and Solubility Between Bioceramic and Resin-Based Sealers (n = 60)

Table 3. Reliability Analysis of Dye Penetration Measurements

The aim of the present laboratory study was to compare the sealing ability and solubility of bioceramic and resin-based root canal sealers. The results showed that the bioceramic sealer had significantly better sealing properties (dye penetration) and the resin-based sealer had significantly lower solubility than the bioceramic sealer. This indicates that after immersion, epoxy resin based sealers still have superior dimensional stability, but bioceramic sealers are more effective in sealing against microleakage. The results obtained indicate that the behavior of both calcium silicate-based and epoxy resin-based materials is very different and that it is not possible to find one material that has all of the ideal properties.

The superior sealing property seen with bioceramic sealer is in line with the study performed by Ismail et al. (2026) which compared hydraulic bioceramic sealers with resin-based sealers with the use of micro-computed tomography (micro-CT). The higher numbers of voids and the lower sealing quality where resin-based ADSeal was used compared with bioceramic sealers were related to the hydrophilic property of calcium silicate materials and their bonding to dentin, they reported. In their study, they found that, similar to the present study, bioceramic sealers seal the root canal system in three dimensions better.[20]

The recent BMC Oral Health (2026) study in vitro compared four bioceramic sealers to AH Plus, and we found their results supported our findings. While investigating the physicochemical properties, the authors also noted that some of the bioceramic materials exhibited excellent adaptation to the canal walls and clinically acceptable physicochemical properties. The adaptation was improved because hydroxyapatite was formed at the sealer/dentin interface, thus improving marginal sealing and reducing the gap of the interface.[21]

Similarly, an earlier experimental study that used fluid filtration and scanning electron microscopy showed significantly improved apical sealing of the bioceramic sealer at all evaluation times compared to AH Plus. The authors noticed that the bioceramic penetrates deeper into the dentinal tubules, which led to better adaptation and leakage. Such observations are entirely similar with the appreciably less dye penetration obtained in the present investigation.[22]

In 2022, a systematic review and meta-analysis found slightly different results. The authors were able to draw conclusions from data obtained from 24 studies conducted in vitro, and found no statistically significant difference in most experimental conditions between the overall sealing ability of the bioceramic and epoxy resin-based sealers. The results of the present study differ from those reported in the other studies included in the review and this may be attributed to the methodological differences between the studies, such as the obturation techniques, the method of leakage assessment, the preparation of the canals, and the type of bioceramic sealer tested.[23]

This study showed that the bioceramic sealer is more soluble than the resin-based sealer. This is similar to the findings of the systematic review and meta-analysis by Silva et al. (2021) which compared the twenty-two laboratory based studies and found that AH Plus had lower solubility than all of the other calcium silicate-based sealers compared, including BioRoot RCS, Bio-C Sealer, EndoSequence BC Sealer, MTA Fillapex, and other calcium silicate-based sealers. The authors propose that, the more these materials release calcium ions, the more mass is lost after immersion.[24]

A similar study conducted in vitro found that both static and dynamic stress affected endodontic sealers. AH Plus was the least soluble throughout the period of observation, while Bio-C Sealer had significantly more dissolution when immersed for an extended period or after thermocycling. Despite the biological benefits of bioceramic sealers, the authors found that epoxy resin-based sealers are still the most dimensionally stable materials. The above observations corroborate the present findings.[25]

A recent comparison study from 2025 compared the solubility and calcium ion release of bioceramic and resin based sealers. The investigators saw significantly higher calcium ion release associated with higher solubility of the bioceramic sealers than of AH Plus. They proposed that this is due to the bioactive mechanism of calcium silicate material and not a defect in the material, as long as the solubility is within the recommended limit by ISO. The higher percentage mass loss found in the present study is in line with these findings.[26]

Another 2026 study to assess the physical characteristics of various bioceramic sealers under thermal cycling conditions confirms the results. The tested bioceramic sealers had the highest solubility values, while AH Plus consistently had the lowest solubility value and the highest and most stable dimensional stability. However, several bioceramic materials had good physicochemical properties, suggesting that material formulation plays a significant role in clinical behavior.[27]

In conclusion, the available evidence indicates that the sealers with hydrophilic characteristics, biomineralization properties, and chemical bonding capacity exhibit better sealing performance, whereas the highly cross-linked polymer matrix of epoxy-resin-based sealers offers superior resistance to dissolution and dimensional change. However, with the primary concern of long-term physicochemical stability, resin-based sealers are still preferred, although bioceramic sealers may be beneficial to reduce microleakage and encourage biological healing. Further laboratory studies using micro-computed tomography, bacterial leakage models, artificial aging, thermocycling, and storage conditions under different conditions are warranted in order to better define the clinical relevance of these physicochemical differences.

There were some limitations in the present study. Being an in vitro laboratory investigation, it could not completely simulate the complex biological and mechanical conditions of the oral environment. The masticatory forces, thermal cycling, salivary enzymes, blood contamination, and periapical tissue responses were not simulated. Findings from the evaluation of just one bioceramic sealer and one epoxy resin-based sealer are not necessarily applicable to all commercially available sealers. The sealing ability was evaluated using a dye penetration method; although widely accepted, this test may not fully simulate bacterial microleakage in the clinical situation. Further, the study had a relatively short observation period and failed to examine aging, bond strength, calcium ion release and clinical success beyond that observation period. These findings should be further validated by using advanced imaging techniques, bacterial leakage models, thermocycling and long-term clinical trials.

The bioceramic sealer showed significantly better sealing ability than the resin-based sealer, as shown by the less dye penetration within the limits of this laboratory-based study. In contrast, the resin-based sealer had much lower solubility, and hence higher dimensional stability, after immersion. The results indicate that the bioceramic sealers have the ability to create a better seal by interacting with dentin, while epoxy resin-based sealers may be more advantageous in terms of dissolution resistance. The choice of an endodontic sealer should therefore be guided by the clinical needs of individual cases, as well as by the long-term physicochemical stability of the sealer. Long-term laboratory and clinical trials are needed to see if these differences mean better clinical results.