Even though endodontics achieved a lot of innovation in both technology and methods, post-operative pain continues to be one of the most prevalent and most difficult complications of root canal treatment (1). The use of rotary and reciprocating instruments, activated irrigation and thermoplastic obturation greatly improved the clinical outcomes; still, many patients complain of pain during the initial healing phase. The reported occurrence of post-operative pain following non-surgical root canal treatment (NSRCT) is known to vary from 2.5% to 60%; reported estimates suggest that almost 40% of patients will experience some pain within the first 24 h of treatment, and nearly 10% will remain symptomatic after one week (2, 3). Persistent post-operative discomfort represents both a clinical challenge and a patient-related issue, affecting satisfaction, acceptance of treatment, and overall perceived quality of care.

There are multifactorial reasons for post-operative pain encompassing mechanical, microbial, and chemical events. The biological interaction of root canal sealers with periapical tissue has received particular attention in the literature, and sealer extrusion and/or irritation may elicit a short-lived inflammatory response, establishing pain and irritation to periradicular tissue (4, 5). Chemical irritants, cytotoxicity, ion release, and interactions of the cement with dentin are important contributors to the extent and duration of post-treatment inflammation (6).

Historically, epoxy resin–based sealers such as AH Plus and ADseal have been considered the gold standard due to their favorable sealing capacity, low solubility, and dimensional stability (7). However, their composition—based on bisphenol-A epoxy resins and amine hardeners—has raised biocompatibility concerns. The release of unpolymerized monomers and trace formaldehyde during polymerization may provoke periapical cytotoxic effects and local inflammatory reactions (8). To overcome these limitations, calcium silicate–based or hydraulic bioceramic sealers were introduced as bioactive alternatives. Bioceramic sealers like EndoSequence BC and iRoot SP have a high biocompatibility due to their alkaline pH and continuous release of calcium and silicate ions, and they promote the formation of hydroxyapatite (9–11). Recently, scientists have been studying these bioceramic sealers at a cellular and tissue level. Inada et al. (12), performed a dentin-tube experiment and showed that a ready-made bioceramic sealer exhibited better bioactivity, porosity, and interfacial adaptation compared to epoxy resin-based sealers, all while showing excellent biocompatibility. Similarly, Shokrzadeh et al. (6), showed the bioceramic sealer had improved mineralization potential and less cytotoxicity to gingival fibroblasts compared to AH Plus. While laboratory studies have consistently shown bioceramic sealers showing superior bioactivity than AH Plus, but it is important to note that clinical evidence has not consistently shown that this translates into reduced postoperative pain or periapical inflammation.

Numerous randomized controlled trials and systematic reviews have compared bioceramic and resin-based sealers in terms of postoperative pain, but the conclusions were contradictory. Some clinical trials noted temporary reduction in early pain after using bioceramic sealers, however, most meta-analyses found there were no clinically meaningful differences (13–17). Even when there are statistically significant differences, the standardized mean differences (SMDs) reported for pain response in these reviews (approximately −0.15 to −0.25) were not of clinically meaningful superiority (18). These differences in findings could have arisen due to several methodological differences such as pulp status, study treatment protocols (single vs. multiple visits), irrigation and obturation techniques and methods of pain response assessment. Further, previous meta-analyses have employed different inclusion criteria and statistics, often from overlapping studies, adding to the complexity in the interpretation of these trials.

Due to this variability, there has been an emerging emphasis on higher order evidence synthesis to improve understanding. Umbrella reviews, a systematic review of systematic reviews, provide a broad approach that accounts for overlapping meta-analytic data, quantifies redundancy and assesses quality using tools like AMSTAR-2 (19). Umbrella reviews are specifically useful in endodontics where multiple reviews repeatedly examine the same questions or sub-questions but have minor inconsistencies in eligibility criteria or statistics.

The present ambiguity surrounding the effect of sealer type on postoperative pain does not result from a dearth of research (20, 21). Rather, the literature is inconsistent, conflicting, and fragmented. Although we have several systematic reviews on the topic, differences in confidence levels and methods for conducting analyses have not resulted in a conclusion (22–24). Therefore, clinicians are faced with a large body of literature that is ambiguous and does not offer clear clinical advice about advantageous postoperative outcomes of bioceramic over resin-based sealers in primary NSRCT.

Accordingly, the purpose of this umbrella review is to critically appraise and synthesize the best available evidence comparing bioceramic and resin-based sealers in primary NSRCT. By considering overlap, methodological quality, and whether there is a certainty of findings in systematic reviews and meta-analyses, this umbrella review aims to clarify the ambiguity that exists and provide clinicians with sound, reliable evidence for sealer selection in endodontics with respect to patient-centered postoperative pain.

Even with advances in instrumentation, irrigation, and obturation technologies, pain after surgery remains a pressing clinical issue in endodontic practice. After all procedures are done in optimal conditions, a good number of patients report pain in the first 24–48 h after root canal treatment (25).Given that pain intensity directly shapes patients' satisfaction and perception of treatment success, identifying and understanding the factors influencing postoperative pain holds both clinical and psychosocial importance (24).

This umbrella review represents the first comprehensive synthesis of systematic reviews and meta-analyses comparing bioceramic (BC) and epoxy resin–based (ER) sealers in primary non-surgical root canal therapy. By examining the findings from seven systematic reviews (five involving quantitative analyses) and conducting a de novo meta-analysis, this study brings together overlapping information to develop a more comprehensive evidence base compared to any single review. The primary conclusion is that even though BC sealers may provide a small, short-term benefit, there is a small reduction in postoperative pain during the first 48 h, which is fleeting, small, and unlikely to be clinically meaningful beyond 48 h.

The current synthesis is consistent with the emerging perspective in recent literature that pain outcomes do not differ significantly between BC and ER sealers. Specifically, Sponchiado Junior et al. (15), reviewed nine RCTs assessing pain incidence or intensity and concluded that there was no difference in either pain incidence or intensity, which they rated as moderate-quality evidence. In addition, Mekhdieva et al. (18), noted lower pain scores at 24 h when treating with BC sealers (SMD = –0.20), but concluded that the degree of reduction was not a clinically meaningful difference. The recent systematic review by Supare et al. (16), supported these findings by concluding other than pain intensity, there were no significant differences with BC sealers related to analgesic use or flare-up rates, thus reinforcing the concept that even if BC sealers do exhibit a benefit early on, its impact is minimal and short-lived.

From a biological perspective, any potential benefit of bioceramic (BC) sealers in the short term could be explained by their chemistry based on calcium silicate. When they hydrate, BC sealers release calcium and hydroxyl ions and create an alkaline environment that could potentially (but temporarily) alter or modulate inflammatory processes around the apex of the tooth, neutralize bacterial by-products, and stimulate surface hydroxyapatite deposition over the sealer-dentin interface (26). These biological effects could be responsible for the small reductions in pain reported in the first 24–48 h. On the other hand, epoxy resin (ER) sealers such as AH Plus could release small quantities of unpolymerized monomers or trace amounts of formaldehyde during the setting process, which may irritate the periapical tissue for a short period of time (27). Importantly, these biological mechanisms do not appear to provide long-term clinical benefit. After they have set, both types of sealer become relatively inert and the extruded material is generally supported/contained by fibrous tissue, resulting in a resolution of inflammation and convergence of pain within a few days. This trend is similar to that reported by Graunaite et al. (13), and Fonseca et al. (14) with regard to postoperative pain that usually diminishes within one week, regardless of the sealer used.

Other umbrella-level syntheses examining alternative factors of postoperative discomfort in endodontics have reported similar results. For example, Abraham et al. (19), noted that changing file kinematics (rotary vs. reciprocating) did not alter postoperative discomfort indicating other procedural factors such as obturation materials or the chemistry of sealers may impact biological processes, but there is infrequently any significant difference in pain experience. Collectively this analysis reinforces the notion that postoperative pain is a multi-factorial event and no one single factor, of which sealer type is just one consideration, will have a significant perceptual truth.

What this means in practical terms for the dentist is simple: the decision to use a certain sealer should not rest with the anticipation of discomfort. Although BC sealers may have a slight short term advantage, their choice should be based generally on material attributes such as handling properties, sealing properties, flowability, biocompatibility, radiopacity, and retreatability (28). In biologically demanding situations—such as vital pulp therapy, cases with immature apices, or single-visit treatments—BC sealers may be advantageous due to their favourable tissue compatibility and alkaline environment (29). However, ER sealers remain dependable and easier to manipulate in routine practice, especially in retreatment cases where retrievability and dimensional stability are paramount (30).

Clinicians who are concerned about postoperative pain should focus on procedural aspects that have a greater influence on pain intensity, such as keeping the apex patent, not over-instrumenting, irrigation protocols, confirming working length, and having a well-sealed coronal restoration (31). Collectively, all of these aspects had a greater influence on patient comfort/postoperative experience compared to the type of sealer used.

A central strength of this umbrella review is the methodological rigor used. The overlap quantification (i.e., Corrected Covered Area, CCA ≈ 12%) minimized the potential for bias from duplicating information across the reviews while the AMSTAR-2 and GRADE frameworks provided transparency in evaluations of methodological quality and certainty of evidence. Overall, the evidence certainty was moderate for short-term pain outcomes, and low for pain outcomes 48 h or longer, with uncertainty due to imprecision and differences in pain assessment instruments. Most of the heterogeneity observed in some of the reviews was methodological (as opposed to statistical) because of participant inclusion criteria (i.e., single vs. multiple visits, pulpal status) and pain assessment intervals, rather than true clinical variability.

Nevertheless, several limitations must be acknowledged. Restricting inclusion to English-language studies may have introduced language bias. The reliability of the present findings depends on the methodological integrity of the included reviews, and any biases within them may have propagated upward. There were numerous variations in pain assessment methods with regard to scale, timing, and reporting of analgesics making direct comparison difficult. Additionally, retreatment and multi-visit cases were underrepresented in the primary studies limiting generalisability, and the majority of primary RCTs had relatively short follow-up durations (≤7 days), thereby preventing assessment of long-term outcomes (e.g., periapical healing, or persisting inflammation). Despite these limitations, research across independent reviews consistently came to similar conclusions that sealer type has only a weak and short-term influence on post-operative pain.

For future research, it should be emphasized that standardizing the investigated protocol, as well as focusing on outcomes that have triaged clinical meaningfulness, should be prioritized or emphasized. Pain should be assessed using a validated and time-restricted method of assessment (e.g., 100-mm VAS), at 6 h, 24 h, 48 h, and 7 days postoperatively, and baseline pain and analgesic use should be accounted for. To reduce variability, multicenter RCTs that are properly powered and employ uniform obturation and irrigation protocols are needed. Compliance with PRISMA 2020 in systematic reviews, preregistered protocols in PROSPERO, accounting for publication bias (which may be modest given the small number of trials per outcome), and systematic review funding considerations around completeness should be considered. Patient-reported outcome measures (PROMs) and quality-of-life indices would increase clinical relevance by moving emphasis away from numerical score to patients' experiences. Mechanistic studies that consider inflammatory biomarkers, including IL-6, TNF-α and substance P may help elucidate the biological nature of postoperative pain. Well-designed clinical trials which assess periapical healing, radiographic bone density, and re-treatability of BC and ER sealers longer after clinical or procedure, will determine if there is an advantage of clinical meaningfulness beyond decreasing transient pain, to some other form of clinical improvement.

This thorough analysis indicates that while bioceramic sealers are slightly less likely than resin-based sealers to result in postoperative pain in the first 48 h, the differences are slight, short-lived, and only somewhat certain. At the end of this time frame, there are no meaningful differences in flare-up rates, analgesics required or pain. It is important to have realistic expectations for the role of sealer type because sealer type is just one of several factors that influence postoperative pain. Altogether, these findings suggest the importance of subtle clinical judgement.