Dental pulp diseases are among the most common clinical conditions in dentistry. The core of their treatment lies in the complete removal of infectious sources and achieving lasting sealing of the root canal system (1, 2). As a key intervention for endodontic and periapical diseases, the long-term success of root canal treatment largely depends on the performance of root canal filling materials and the precision of clinical procedures (3, 4). For decades, traditional epoxy resin-based sealers (such as AH Plus) have been widely used due to their high mechanical strength and stable physicochemical properties (5, 6). However, these materials also have significant limitations: slight shrinkage may occur during polymerization, leading to microleakage; chemical components in their composition may cause tissue irritation; furthermore, their performance in terms of biocompatibility and promoting peripheral tissue regeneration is relatively limited (7–9).

In recent years, with advancements in biomaterials science, novel bioceramic-based root canal sealers have been gradually applied in clinical practice and have demonstrated significant advantages (5, 10). These materials primarily consist of calcium silicate, with representative products including internationally widely used iRoot SP and domestically produced C-Root SP, among others (11, 12). Upon contact with tissue fluids, they undergo a hydration reaction, generating nano-hydroxyapatite, which forms a chemical bond with the dentinal wall, greatly enhancing apical sealing ability (13, 14). Studies have shown that such materials not only exhibit excellent biocompatibility and antimicrobial activity but also promote osteogenic differentiation and cementum regeneration, demonstrating great potential in improving the healing environment of periapical tissues (15, 16).

With the evolution of obturation strategies, the hydraulic single-cone technique used with bioceramic sealers has gained popularity because of its procedural simplicity and reduced technique sensitivity, potentially improving efficiency in complex anatomies such as curved or C-shaped canal systems. Nevertheless, the relatively high flow and larger volume of sealer used in single-cone fillings may increase the risk of sealer extrusion/overfilling. In addition, the strong dentin bonding and mineral infiltration associated with premixed bioceramic sealers may compromise retreatability, making complete removal more challenging during non-surgical retreatment (17, 18).

Although several studies have explored the application effects of bioceramic sealers in root canal treatment, there is still a lack of systematic integration of large-sample, multicenter clinical data. Particularly regarding direct comparisons with traditional materials, key indicators such as postoperative pain control, microleakage performance, long-term sealing stability, and retreatability feasibility remain controversial or inadequately supported by evidence. Furthermore, previous literature has mostly focused on discussions of individual indicators, lacking a multidimensional analysis from the perspective of comprehensive clinical efficacy (19).

Therefore, this study aims to comprehensively compare multiple outcome indicators of novel bioceramic sealers versus traditional epoxy resin-based sealers in root canal treatment using the single-cone technique through systematic review and meta-analysis. These indicators include the incidence of postoperative pain, apical sealing ability, depth of dentinal tubule penetration, occurrence of overfilling, retreatment difficulty, and success rate, thereby providing evidence-based references for clinical material selection and operational standards.

This systematic review and meta-analysis comprehensively compared multiple key efficacy indicators between the single-cone technique with novel bioceramic sealers and traditional epoxy resin-based sealers (AH Plus) in root canal treatment. The results demonstrated that bioceramic sealers showed significant advantages in postoperative pain control (OR = 0.48) and apical sealing performance (SMD = −1.35). However, they were also associated with a higher risk of overfilling (OR = 1.85) and increased difficulty in retreatment (SMD = 0.88), while mid-term clinical success rates were comparable between the two groups (OR = 1.12). These findings are largely consistent with the current research consensus in the field. Through the inclusion of 15 studies and 1,528 teeth in this large-sample analysis, we were able to more comprehensively evaluate the benefits and challenges of their clinical application.

The 52% significant reduction in postoperative pain incidence in the bioceramic group can be reasonably explained by the material’s biological properties and by existing clinical evidence comparing bioceramic and epoxy resin-based sealers. Traditional epoxy resin–based sealers may induce periapical irritation mainly through setting-related released byproducts/unpolymerized residues with cytotoxic potential, which can contribute to inflammatory responses, particularly when the material contacts periradicular tissues (20). In contrast, calcium silicate–based bioceramic sealers undergo hydration, generating calcium silicate hydrate and calcium hydroxide, thereby maintaining an alkaline pH and continuously releasing Ca²⁺ and OH⁻ ions during/after setting (21). This sustained alkaline environment is associated with antibacterial/antibiofilm activity, which may help suppress residual infection and modulate the local inflammatory microenvironment (22). Moreover, because these sealers set via a hydraulic reaction and do not require external heat, they avoid heat-related concerns that are mainly discussed in the context of warm obturation procedures (23). Subgroup analysis indicated a numerically superior trend in pain control at 24 and 48 h postoperatively; these early time points are commonly used for postoperative pain assessment in endodontic trials, and early pain control is clinically relevant because dental anxiety and related psychological factors are associated with postoperative pain perception and the overall treatment experience (24).

In terms of apical sealing ability, bioceramic sealers showed significantly better performance than conventional sealers in our synthesis, which is directionally consistent with multiple laboratory studies reporting reduced apical leakage for calcium silicate-based sealers compared with epoxy resin–based sealers under specific test conditions (25). For epoxy resin–based sealers such as AH Plus, adhesion to dentin is generally attributed to a combination of micromechanical retention (tubular tags) and chemical interaction, including covalent bonding between epoxy groups and exposed amino groups within the dentin collagen network (20). As polymerizing resin sealers set within the unfavorable geometry of the root canal, polymerization-related stresses and dimensional changes can contribute to interfacial gap formation, thereby increasing the risk of microleakage over time (5). In contrast, calcium silicate–based bioceramic sealers are “hydraulic” materials that require moisture for a hydration reaction, producing calcium silicate hydrate (a gel-like hydrated phase) and calcium hydroxide, with subsequent calcium and hydroxyl ion release (14). In a moist canal environment and in the presence of tissue-fluid phosphate, these sealers can promote hydroxyapatite deposition at the sealer–dentin interface, creating a bioactive mineral interfacial layer that enhances bonding and sealing (14). Evidence syntheses further report favorable dentinal tubule penetration and interfacial adaptation for premixed bioceramic sealers, supporting a mechanism where mineralization and micromechanical interlocking jointly improve the quality of the seal (26). Although considerable heterogeneity was observed (I² = 71%), this is plausibly explained by methodological differences across studies (e.g., different leakage outcomes, imaging modalities, and test setups), which is a recognized driver of heterogeneity in microleakage meta-analyses (27). From a clinical perspective, because the fundamental objective of obturation is to achieve a durable hermetic seal that limits reinfection, a bioactive sealing mechanism that reduces pathways for microbial leakage is mechanistically relevant to long-term endodontic success (27). Nevertheless, apical microleakage and dentinal tubule penetration are surrogate or laboratory-based endpoints and should be viewed as complementary mechanistic evidence rather than being equated directly with hard clinical outcomes such as tooth survival or radiographic healing.

However, excellent flowability and bioactivity also come with a higher risk of overfilling (OR = 1.85). From a mechanistic standpoint, sealers with higher flow are more likely to be extruded beyond the apical foramen, and ISO-based discussions explicitly note that excessive flow increases the risk of extrusion beyond the apex (28). In single-cone obturation, the technique is inherently “sealer-dependent” (i.e., a relatively larger volume of sealer is involved compared with warm gutta-percha techniques), which can further increase the likelihood of apical sealer extrusion when the material is highly flowable (29). A recent review of periapically extruded calcium silicate cements similarly reported that periapical healing is common even when extrusion occurs, supporting the concept that limited extrusion may not invariably translate into adverse long-term outcomes (30). Nevertheless, extrusion can still be clinically relevant because trials have specifically evaluated the relationship between sealer extrusion and early postoperative pain/discomfort, indicating that extrusion may contribute to short-term symptoms in some patients (31). Therefore, corresponding clinical strategies must be adopted to control this risk, such as creating a well-defined apical “stop,” selecting gutta-percha cones that match the master apical file, and avoiding excessive vertical condensation force.

On the other hand, the excellent sealing and chemical adhesion of bioceramic materials are a “double-edged sword,” significantly increasing the difficulty of retreatment (SMD = 0.88). This reduced retreatability is commonly attributed to their strong dentin interaction/mineral infiltration and deep tubular penetration, which often requires longer working time and adjunctive approaches during removal (32). Accordingly, studies evaluating removal protocols frequently incorporate supplementary passive ultrasonic irrigation and combinations of retreatment NiTi systems and/or solvents to improve the removal of bioceramic sealer remnants (33). The observed heterogeneity in retreatment outcomes (I² = 45%) is plausibly related to differences in retreatment protocols and evaluation metrics (e.g., micro-CT residual volume vs. other endpoints, solvent use, file systems, and adjunct activation), underscoring the need for a more standardized retreatment evaluation framework (34). Clinically, given this trade-off, case selection at the initial treatment stage should consider prognostic uncertainty, balancing the long-term sealing advantages of bioceramic sealers against potential future retreatment challenges (32).

It is noteworthy that although bioceramic materials perform excellently in short-term outcomes, their mid-term (6–24 months) clinical success rate showed no significant difference from traditional materials (OR = 1.12). This indicates that both materials are equally effective in achieving the ultimate treatment goal of periapical tissue healing, with the advantages of bioceramic materials being more reflected in the biological responses and sealing performance during the treatment process.

This study also has several notable strengths. First, to our knowledge, it is one of the few systematic reviews and meta-analyses focusing specifically on calcium silicate–based bioceramic sealers used with the single-cone technique, synthesizing data from 15 clinical studies and 1,528 teeth. Second, we included both randomized controlled trials and prospective or retrospective cohort studies and applied contemporary risk-of-bias tools (RoB 2.0 and the NOS), which enhances the methodological transparency of this review, and we synthesized these studies in pooled analyses because they addressed similar populations, interventions, comparators, and outcomes. Third, our search strategy followed PRISMA recommendations and covered both major international databases and Chinese databases over the past decade, which helps to reduce language and publication bias and to improve the generalizability of the findings across different clinical settings. Nevertheless, this study has several limitations. First, the follow-up periods of the included studies were generally short, and all reported success rates were limited to 6–24 months, lacking data on long-term efficacy (e.g., success rates beyond 5 years). As a result, the pooled success rates in this review should be interpreted as reflecting only short- to mid-term outcomes. Second, differences in root canal preparation procedures, obturation technical details, and postoperative pain assessment criteria among studies may have introduced clinical heterogeneity. Additionally, there is a lack of standardized metrics for evaluating retreatment difficulty. In the available studies, retreatability was assessed mainly by retreatment time in a small number of cases, with limited information on residual filling material, re-establishment of apical patency, or patient-centred outcomes, which restricts the generalizability of this endpoint. Third, although the majority of included studies were randomized controlled trials, we also pooled a smaller number of prospective or retrospective cohort studies in the same meta-analyses. Different study designs inherently carry different risks of bias and residual confounding; therefore, the pooled estimates—especially for outcomes relying heavily on non-randomized data—should be interpreted with appropriate caution. Finally, we did not perform a formal GRADE assessment of the overall certainty of evidence; consequently, the strength of our conclusions is expressed qualitatively and should be viewed in the context of the observed heterogeneity and mixed study designs. Future research should establish more unified assessment systems for operation time, efficiency, and safety and incorporate formal certainty-of-evidence grading.

In conclusion, this meta-analysis indicates that the use of the single-cone technique with novel bioceramic sealers (such as iRoot SP, Bio-C Sealer, and C-Root SP) offers significant advantages over traditional epoxy resin-based sealers (e.g., AH Plus) in reducing postoperative pain and improving apical sealing ability in root canal treatment, demonstrating favorable bioactivity and antibacterial properties. However, these materials are also associated with a higher risk of overfilling and may increase the difficulty of retreatment, while mid-term clinical success rates are comparable between the two groups. Therefore, when adopting this technique, clinicians should strictly master its indications. Bioceramic materials may be prioritized for cases where postoperative comfort and excellent sealing are pursued, but meticulous apical preparation and pressure control during operation are essential to maximize benefits and minimize risks. Future well-designed studies with longer follow-up periods are still needed to further validate their long-term efficacy and optimize clinical protocols.