Effect of rotary and reciprocating instrumentation kinematics on postoperative pain following endodontic retreatment: a systematic review

Abstract

This review aimed to systematically evaluate whether rotary or reciprocating nickel–titanium instrumentation systems influence postoperative pain after nonsurgical endodontic retreatment. This systematic review was conducted according to PRISMA 2020 guidelines and prospectively registered in PROSPERO (CRD420261325110). A comprehensive electronic search was conducted in the PubMed, Scopus, Web of Science, and Embase databases. Randomized clinical trials comparing rotary and reciprocating systems for nonsurgical endodontic retreatment and reporting postoperative pain outcomes were included. Risk of bias was assessed using the Modified Cochrane RoB-2 tool. Due to clinical and methodological heterogeneity, a qualitative synthesis was performed. A total of 194 records were identified through a database search, and five randomized clinical trials fulfilled the inclusion criteria. Most studies reported no statistically significant differences in the incidence or intensity of postoperative pain between the rotary and reciprocating retreatment systems at 24, 48, and 72 h. However, one randomized clinical trial reported significantly higher early postoperative pain associated with the reciprocating system than with the rotary system during the initial postoperative period, whereas no significant difference was observed at longer follow-up intervals. Furthermore, no statistically significant differences were observed between the rotary and reciprocating kinematics regarding analgesic intake following the retreatment procedures. Based on available randomized evidence, rotary and reciprocating instrumentation systems appear to produce comparable postoperative pain following nonsurgical endodontic retreatment. Postoperative discomfort is generally mild, decreases over time, and does not demonstrate a consistent dependence on instrumentation kinematics.

INTRODUCTION

Root canal therapy seeks to substantially reduce the intracanal microbial load through the effective removal of pulp tissue, infected dentin, necrotic debris, and organic remnants [1]. Despite advances in endodontic therapy, postoperative pain and/or swelling following root canal procedures continue to pose a clinical challenge for both patients and clinicians. Despite the high success rates associated with primary orthograde endodontic therapy, post treatment diseases remain prevalent [2]. The evidence presented by Ricucci indicates that primary and post treatment periapical lesions are consistently associated with the presence of intraradicular and/or extraradicular bacteria [3]. The most common causes of post treatment disease are incomplete chemomechanical debridement, persistence of bacteria in the canals, poor obturation quality, over- and under-extension of root canal filling, and coronal leakage [4]. For patients exhibiting persistent pathosis after root canal treatment, nonsurgical endodontic retreatment is strongly recommended as a first-line therapeutic option [5]. Previous meta-analyses have indicated that nonsurgical endodontic retreatment achieves a pooled success rate ranging from 76.7% to 77.8%, with variability attributed to factors such as preoperative periapical status, lesion size, and coronal restoration quality [6,7].

Postoperative pain may occur following retreatment of teeth previously treated with a root canal. The patient’s response to pain varies according to clinical circumstances, and pain perception is not always continuous. Although endodontic instruments do not extend into the periradicular tissues during nonsurgical root canal retreatment, debris, residual root canal filling materials, irrigants, remaining pulp tissue, and microorganisms may be inadvertently extruded beyond the apical foramen [8]. The extrusion of microorganisms during chemomechanical preparation may transiently disturb the equilibrium between apically displaced irritants and host immune defenses, thereby triggering an acute inflammatory response aimed at reestablishing homeostasis [9]. Accordingly, apical extrusion has been shown to be associated with periradicular inflammation, postoperative pain, flare-ups, and delayed periapical healing [10,11]. Operator-related factors, including clinical skill and experience, may also play a role in apical debris extrusion and subsequent pain perception [12].

The instrument performance during canal preparation is governed by differences in file geometry, material properties, and resistance to deformation. Consequently, the extent of apical debris extrusion varies depending on the instrumentation system used [13]. Nickel–titanium instruments operate using different kinematic patterns, such as continuous rotation, reciprocation, or hybrid movements. Continuous rotation is characterized by uninterrupted 360° rotation in a single direction, whereas reciprocation consists of alternating clockwise and counterclockwise motions repeated in a cyclical manner [14]. A systematic review and meta-analysis conducted by Martins et al. reported that reciprocating instrumentation is associated with a reduced frequency of postoperative pain compared with rotary motion [15]. In contrast to previous findings, da Silveira et al. reported that the rotary system was associated with lower severity of postoperative pain after endodontic procedures [16]. However, some studies have indicated that postoperative responses do not differ significantly between the rotational and reciprocating file systems [17,18].

Despite several systematic reviews on postoperative pain after primary endodontic therapy, evidence specifically addressing retreatment remains limited. To the best of our knowledge, no systematic review has exclusively evaluated the influence of instrumentation kinematics on postoperative pain in patients undergoing retreatment. Given the distinct clinical challenges associated with retreatment, including the removal of existing filling materials and the increased risk of debris extrusion, findings from the primary treatment cannot be directly extrapolated. Additionally, the existing literature reports conflicting findings regarding postoperative pain associated with the rotary and reciprocating systems. Therefore, this systematic review aimed to evaluate and compare postoperative pain after nonsurgical endodontic retreatment using rotary and reciprocating instrumentation systems, thereby providing clinically relevant evidence for retreatment scenarios. The secondary objective was to assess pain intensity at different postoperative time intervals.

METHODS

1. Study design and research question

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines [19] and was registered in the PROSPERO International Prospective Register of Systematic Reviews (CRD420261325110). This review aimed to address the following research question: In patients undergoing nonsurgical endodontic retreatment, does the use of reciprocating nickel–titanium instrumentation systems, compared with rotary nickel–titanium instrumentation systems, influence the incidence and severity of postoperative pain?

The research question was structured using the PICO framework as follows: population (P), patients undergoing nonsurgical endodontic retreatment; intervention (I), retreatment performed using reciprocating nickel–titanium instrumentation systems; comparison (C), retreatment performed using rotary nickel–titanium instrumentation systems; and outcome (O), incidence and intensity of postoperative pain.

2. Eligibility criteria

Randomized controlled trials conducted on human participants were included if they compared reciprocating and rotary nickel–titanium instrumentation systems during nonsurgical endodontic retreatment of permanent teeth, and clearly described the methods used for postoperative pain assessment. Studies were excluded if they were not published in English, had a follow-up period of less than 48 h, were unavailable in full-text form, or were laboratory-based studies, animal experiments, case reports, or review articles.

1) Search Strategy

Two reviewers (P.S and A.B) independently performed a systematic literature search. To ensure accuracy and completeness of the strategy, a third reviewer further evaluated the search strategy (S.A). The search approach incorporated both relevant keywords and their corresponding Medical Subject Headings (MeSH) to maximize the retrieval of potentially eligible studies.

Electronic databases, including PubMed/MEDLINE, Scopus, Embase, and Web of Science, were systematically searched for articles published between February 25, 2016, and February 25, 2026. The search strategy combined terms associated with endodontic retreatment procedures, nickel–titanium instrumentation systems, and postoperative pain outcomes. The detailed search strategy used for each database is presented below.

2) PubMed/MEDLINE

((endodontics[MeSH] AND postoperative pain [MeSH]) OR (endodontic retreatment OR root canal retreatment) AND (pain OR postoperative pain OR post-endodontic pain OR post-treatment pain) AND (continuous rotation OR rotary OR nickel-titanium OR nickel-titanium instrumentation OR reciprocating OR Reciprocation))

3) Scopus

TITLE-ABS-KEY((endodontics AND "postoperativepain") OR ("endodontic retreatment" OR "root canal retreatment") AND ("pain" OR "postoperative pain" OR "post-endodontic pain" OR "post-treatment pain") AND ("continuous rotation" OR "rotary" OR "nickel-titanium" OR "nickel-titanium instrumentation" OR "reciprocating" OR "reciprocation"))

4) Web of Science

TS=((endodontics AND "postoperative pain") OR ("endodontic retreatment" OR "root canal retreatment") AND ("pain" OR "postoperative pain" OR "post-endodontic pain" OR "post-treatment pain") AND ("continuous rotation" OR "rotary" OR "nickel-titanium" OR "nickel-titanium instrumentation" OR "reciprocating" OR "reciprocation"))

5) Embase

((endodontics AND "postoperative pain")OR ("endodontic retreatment" OR "root canal retreatment") AND ("pain" OR "postoperative pain" OR "post-endodontic pain" OR "post-treatment pain") AND ("continuous rotation" OR "rotary" OR "nickel-titanium" OR "nickel-titanium instrumentation" OR "reciprocating" OR "reciprocation"))

3. Study selection and data extraction

The study selection process was independently performed by two reviewers (P.S. and A.B.). Titles and abstracts identified through an electronic database search were screened to determine their relevance. Full-text articles of potentially eligible studies were retrieved and evaluated according to the predefined inclusion and exclusion criteria. Any differences in opinion between the reviewers were resolved by discussion until a consensus was reached.

Data were independently extracted by the same two reviewers using a standardized data collection form. The following information was obtained from each included study: author and year of publication, country of origin, study design, sample size, type of tooth, preoperative condition, instrumentation systems used, irrigation protocol, obturation technique, method used for pain assessment, postoperative pain evaluation time points, reported incidence and intensity of postoperative pain, use of analgesics, and the principal findings of the study.

To ensure the reliability of the extracted information, all collected data were cross-checked by the reviewers, and a third reviewer (S.A.) performed the final verification. When important details were missing or unclear, the corresponding authors were contacted to obtain additional information whenever possible.

This structured screening and data collection process aligned with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA, 2020).

4. Risk of bias assessment

The risk of bias of the included randomized controlled trials was assessed using the modified Cochrane Risk of Bias -2 (RoB-2) tool [20]. The domains evaluated were randomization process, deviations from intended interventions, missing outcome data, measurement of the outcome, and selection of reported results. Each study was categorized as having a low risk of bias, some concerns, or a high risk of bias. Assessments were performed independently by two reviewers, and discrepancies were resolved by discussion until an agreement was reached.

5. Data synthesis and analysis

Considerable clinical and methodological variability was identified in the included studies. Differences were noted in the methods used for pain evaluation, including the visual analog scale (VAS), numeric rating scale, and verbal rating scale, as well as in the timing of postoperative assessments and the manner in which outcomes were reported. Due to this heterogeneity, conducting a quantitative meta-analysis was not considered appropriate.

Instead, the findings were summarized through a narrative qualitative synthesis. The reported statistical outcomes from the included trials, such as p-values and confidence intervals when available, were extracted and presented as described in the original studies. In addition, changes in the outcomes within each study over different follow-up periods were documented. Descriptive comparison was performed to identify general patterns related to postoperative pain intensity and analgesic medication use across the included studies.

RESULTS

1. Search results

The database search identified 194 records (PubMed = 66; Scopus = 81, Embase = 12, and Web of Science = 35). After removing 78 duplicates, 116 articles were screened based on their titles and abstracts. A total of 108 studies were excluded during title and abstract screening. The full texts of eight articles were assessed for eligibility, and three studies were excluded because of ineligible study designs or different comparator groups. Ultimately, five randomized clinical trials were included in the qualitative synthesis [21,22,23,24,25] (Fig. 1).

Fig. 1. PRISMA flow diagram (2020) for the systematic review. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-analyses.

2. Population

Five randomized clinical trials involving 554 participants were included in this review [21,22,23,24,25]. One study was conducted in Brazil [21], while the remaining studies were conducted in Türkiye [22,23,24,25]. Patients with different tooth types, including single-rooted anterior teeth [22,25], mandibular premolars [24], and a combination of maxillary and mandibular teeth requiring retreatment [21,23]. All included trials evaluated teeth requiring nonsurgical endodontic retreatment because of the development of post treatment endodontic disease [21,22,23,24,25].

Radiographic inclusion criteria varied among the studies. Some trials specifically included teeth diagnosed with chronic apical periodontitis [25], whereas others included teeth presenting with radiographic evidence of periapical lesions associated with a previously treated tooth periapical index (PAI > 4) [21,22,26]. One study included previously treated, asymptomatic teeth with periapical lesions (PAI > 2) [23].

Among the five included trials, three enrolled patients who were asymptomatic before treatment [22,23,25], while the remaining two studies included patients with and without preoperative pain [21,24]. Most studies excluded patients with systemic diseases, recent analgesic intake, or other clinical conditions that could influence postoperative pain outcomes [21,22,23,24,25] (Table 1) (Supplementary Table 1).

Table 1. Characteristics of Included studies.

Author (year)	Study design	Sample size (n) and tooth type	Preoperative pain	Rotary system	Reciprocation system
Güneç et al. (2025) [24]	Single-center, prospective randomized clinical trial	80 Mandibular premolars (single-rooted)	Both present and absent	One Curve Mini	One RECI
Çanakçi et al. (2021) [22]	Prospective randomized clinical trial	175 Single-rooted incisor teeth with single canals	Absent	ProTaper Universal; HyFlex EDM	Reciproc Blue; WaveOne Gold
Eyuboglu & Özcan (2019) [23]	Single-center, single-blind, prospective randomized clinical trial	99 Mixed tooth types (maxillary/mandibular; anterior/premolar/molar)	Absent	One Shape; Revo-S	WaveOne
Comparin et al. (2017) [21]	Single-center, single-blind, prospective randomized clinical trial	65 Mixed tooth types (maxillary/mandibular; anterior/premolar/molar)	Present/Absent	Mtwo (VDW)	Reciproc R25 file
Topçuoğlu et al. (2017) [25]	Single-center randomized clinical trial	135 Single rooted maxillary incisors	Absent	ProTaper Universal Retreatment (PTUR)	Reciproc system (VDW)

3. Intervention

Four studies compared postoperative pain following endodontic retreatment using rotary and reciprocating nickel–titanium instrumentation systems [21,22,23,24], while one study compared these techniques with hand-file instrumentation [25].

Continuous rotary instrumentation systems such as Mtwo retreatment files [21], ProTaper Universal Retreatment files [22,25] and Hyflex EDM [22], One Shape, Revo-S [23], and One Curve Mini [24] were used across the included studies. Reciprocating instrumentation systems including Reciproc [21,25], ReciprocBlue and WaveOne Gold [22], WaveOne [23], and One RECI [24] were evaluated for the removal of root canal filling material during retreatment procedures. In addition, one study included hand file instrumentation using stainless-steel files as a comparison group during retreatment [25].

All studies used electronic apex locators in combination with radiographic verification to determine the working length [21,22,23,24,25]. Sodium hypochlorite (NaOCl) was used as the primary irrigating solution in all studies, although its concentration varied. The most frequently used concentration was 2.5% NaOCl [21,22,23,25], whereas one study used 5.25% NaOCl during retreatment procedures [24]. The final irrigation protocol used 17% EDTA to remove the smear layer.

In most studies, the treatment procedures were performed in a single visit [21,22,23,24]. However, one study employed a two-visit protocol using calcium hydroxide as an intracanal medication between appointments [25] (Table 1) (Supplementary Table 1).

4. Outcome assessment

Postoperative pain was the primary outcome evaluated in all the included studies [21,22,23,24,25]. Pain intensity was assessed using different validated pain assessment tools across trials. One study assessed postoperative pain using the visual analog scale (VAS), with scores ranging from 0 to 10 [24]. One study used a numerical rating scale (NRS) ranging from 0 to 10 for pain assessment [22]. One study used verbal rating scales to categorize pain intensity into different levels, which were reported as categorical data [21]. Two studies used a four-point verbal pain scale ranging from no pain to severe pain [23,25]. Pain was evaluated at multiple postoperative time intervals across studies. The most common assessment periods were 24, 48, and 72 h after the retreatment procedures [21,22]. Some studies recorded pain at earlier and later intervals, including 6 and 12 hours, as well as follow-up periods of up to 7–14 days after treatment [23,24,25].

In addition to postoperative pain intensity, several studies recorded analgesic consumption as a secondary outcome, typically prescribing ibuprofen or other nonsteroidal anti-inflammatory drugs for pain control [21,22,23,24,25]. A summary of the outcome measures and reporting methods is presented in Table 2 and Supplementary Table 2. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework, which considers domains such as risk of bias, inconsistency, indirectness, imprecision, and publication bias [27] (Table 3).

Table 2. Outcomes from the studies.

Author (year)	Pain assessment method	Time interval	Pain outcome (rotary)	Pain outcome (reciprocation)	Analgesic intake reported	Conclusion
Güneç et al. (2025) [24]	VAS	24 h; 48 h; 72 h; 7 d; 14 d	AT: 2.1→0.55; ST: 2.6→0.3	AT: 2.25→0.05; ST: 3.0→0	Yes – Ibuprofen 600 mg	No significant difference
Çanakçi et al. (2021) [22]	NRS	24 h; 48 h; 72 h	PTUR: 3.7→0.5; HyFlex: 2.9→0.8	Reciproc Blue: 3.2→0.8; WOG: 3.2→0.6	Yes – Ibuprofen 400 mg	No significant difference
Eyuboglu & Özcan (2019) [23]	4-level VRS	6 h; 12 h; 18 h; 24 h; 48 h; 72 h; 7 d; 1 month	One Shape: 0.67→0; Revo-S: 1.52→0	WaveOne: 2.45→0	Yes – Naproxen sodium 550 mg	Reciprocating system showed higher early pain; no difference at 1 month.
Comparin et al. (2017) [27]	VRS	24 h; 48 h; 72 h	None 60→93%	None 65→97%	Yes – Ibuprofen 400 mg.	No significant difference
Topçuoğlu et al. (2017) [25]	4-point VPS	6 h; 12 h; 24 h; 48 h; 72 h; 7 d; 10 d	PTUR: 0.9→0	Reciproc: 1.0→0	Yes – Ibuprofen	Hand files produced significantly higher postoperative pain (p=0.02); no difference between rotary and reciprocating systems

AT, Asymptomatic; NRS, Numeric Rating Scale; PTUR, ProTaper Universal; ST, Symptomatic; VAS, Visual Analogue Scale; VPS, Verbal pain scale; VRS, Verbal rating scale.

Table 3. Assessment of the certainty of evidence using the GRADES approach.

Outcome	No. of studies	Participants	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Publication bias	Certainty of evidence
Postoperative pain (24 h)	5	554	RCTs	Some concerns (blinding unclear in some trials)	Moderate heterogeneity in pain scales	Not serious	Sample sizes relatively small	Undetected	Moderate
Postoperative pain (48 h)	5	554	RCTs	Some concerns	Moderate heterogeneity	Not serious	Moderate imprecision	Undetected	Moderate
Postoperative pain (72 h)	5	554	RCTs	Some concerns	Moderate heterogeneity	Not serious	Moderate imprecision	Undetected	Moderate
Analgesic intake	4	554	RCTs	Some concerns	Low heterogeneity	Not serious	Moderate imprecision	Undetected	Moderate

5. Risk of bias

The methodological quality of the included studies was assessed using the modified Cochrane Risk of Bias 2 (RoB-2) tool for randomized clinical trials. Overall, the included studies demonstrated a low-to-moderate risk of bias. Two studies were judged to have an overall low risk of bias, as they adequately described the randomization process, reported minimal or no missing outcome data, and clearly measured postoperative pain using validated scales [22,23]. The remaining three studies were assessed as having some concerns, primarily because of insufficient information regarding the blinding of participants and operators [21,24,25].

Across the included trials, the domains related to missing outcome data and measurement of outcomes were generally considered to be at low risk of bias, as postoperative pain was assessed using standardized pain scales and follow-up was adequately reported. However, operator blinding was not feasible in most studies because of the nature of the instrumentation procedures, which contributed to the classification of some studies as having concerns in the domain of deviations from intended interventions, as shown in Figures 2a and 2b.

Fig. 2. (A) Traffic light plots of the risk of bias assessment of the studies according to the modified Rob-2 tool. (B) Domain-wise summary of the risk of bias assessment.

6. Data synthesis

Postoperative pain was assessed at multiple time intervals across the included studies, most commonly at 24, 48, and 72 hours following endodontic retreatment. Overall, postoperative pain tended to be highest within the first 24 hours and gradually decreased over time, irrespective of the instrumentation technique used.

Across the included trials, no statistically significant difference was observed between rotary and reciprocating instrumentation systems in terms of postoperative pain intensity at 24, 48, and 72 hours [21,22]. Similarly, another study reported comparable postoperative pain levels between rotary and reciprocating systems, with pain scores decreasing over time [24]. Eyüboğlu andÖzcan reported higher early postoperative pain scores associated with reciprocating instrumentation [23], although the difference was not significant (P > 0.05) at later follow-up periods. In addition, a randomized clinical trial comparing hand files and rotary and reciprocating techniques demonstrated that hand instrumentation produced significantly higher postoperative pain during the first 48 hours (P < 0.05), whereas no statistically significant difference was observed between the rotary and reciprocating groups (P > 0.05) [25].

Across all included studies, postoperative pain progressively declined with time, and by the later follow-up periods (7–14 days), pain levels were generally minimal regardless of the instrumentation technique used [23,24,25]. Analgesic intake was also reported in several studies and was generally low and comparable across instrumentation techniques, with nonsteroidal anti-inflammatory drugs such as ibuprofen being the most prescribed medication [21,22,23].

Due to clinical and methodological heterogeneity among the included trials, including differences in pain assessment scales, study designs, and outcome reporting methods, a quantitative meta-analysis was not performed, and the results were summarized using a qualitative synthesis approach.

DISCUSSION

This systematic review evaluated postoperative pain following nonsurgical endodontic retreatment using rotary and reciprocating nickel–titanium systems. Based on the included studies, the evidence did not indicate the uniform superiority of either kinematic approach. Taken together, these studies show that the relationship between kinematics and postoperative pain is complex. While one trial favored rotary motion, others found no significant differences or reported broadly similar pain patterns over time [21,22,23,24,25]. A plausible explanation for these discrepancies is that post-operative pain after retreatment is multifactorial. Previous studies have shown that postoperative pain may be affected by the preoperative status, extrusion of infected debris, apical tissue irritation, operator technique, working length control, irrigation regimen, and tooth-related variables such as anatomy and periapical condition [8,28,29]. Arias et al. identified preoperative and treatment-related factors as important predictors of post-treatment pain [28], whereas Siqueira and Rôças emphasized the role of microbial and inflammatory factors in persistent endodontic disease [8]. These observations support the view that instrumentation motion is only one component of a broad range of biological and mechanical processes.

Another relevant finding was the possible association between postoperative pain and apical debris extrusion. Experimental studies have reported conflicting results regarding whether rotary or reciprocating systems extrude more material apically during retreatment [30,31]. Some authors have suggested that reciprocating motion may increase extrusion because of its filling dynamics [32], whereas others have shown no meaningful difference or even less extrusion than rotary systems [31]. This inconsistency in laboratory evidence is mirrored by the inconsistent clinical findings in the present review. The fact that clinical pain outcomes do not consistently parallel in vitro extrusion results suggests that postoperative pain is not determined by debris extrusion alone, but rather by the interaction between extruded irritants and the host response [8,28,29].

The trials included differed in several respects. Comparin et al. included mixed-tooth groups and found that preoperative pain and sex influenced postoperative pain more than the retreatment technique itself [21]. Eyüboğlu and Özcan used three shaping systems with different design features, apical preparation approaches, and a broader range of tooth types, which may partly explain why WaveOne produced higher pain scores [23].Çanakçi et al. restricted the sample to asymptomatic single-rooted incisor teeth and standardized treatment more tightly, which may have reduced clinical variability and contributed to the absence of significant differences [22].

Analgesic intake across the included studies was generally low, and no consistent differences were observed between kinematics. Comparin et al. andÇanakçi et al. found no significant difference in ibuprofen consumption between groups, with only a few patients requiring analgesics [21,22]. This supports the interpretation that, although transient pain may occur after retreatment, its overall clinical burden is usually limited and tends to decrease within the first few postoperative days.

The certainty of the evidence assessed using the GRADE approach was low to very low primarily because of the limited number of randomized clinical trials, heterogeneity in study designs, and variations in outcome assessment methods. This finding suggests that the current evidence provides only limited confidence in the observed findings, and further high-quality studies may substantially influence these estimates.

Limitations

The methodological quality of the included studies was generally acceptable; however, some limitations should be acknowledged. Differences in pain assessment methods, follow-up intervals, sample characteristics, and treatment protocols have reduced the comparability between studies. In addition, some studies used categorical scales, whereas others used continuous pain scales, limiting direct comparisons and preventing meaningful quantitative pooling. These variations weaken the certainty of any conclusion regarding the effect of instrumentation motion on postoperative pain.

Clinical implications

From a clinical perspective, the present findings suggest that neither the rotary nor reciprocating systems can be considered definitively superior in terms of postoperative pain after retreatment. Rotary systems may offer advantages in the early postoperative context, as suggested by Eyüboğlu and Özcan, but this was not consistently reproduced in the other included trials. Therefore, instrument selection in retreatment should likely depend not only on expected pain outcomes but also on factors such as canal anatomy, efficiency of filling removal, operator familiarity, and overall treatment objectives.

Conclusion

Within the limitations of the available evidence, no consistent difference in postoperative pain was observed between the rotary and reciprocating instrumentation systems following nonsurgical endodontic retreatment. However, the limited number of studies and heterogeneity in study design and outcome assessment reduce the certainty of these findings. Therefore, the results should be interpreted with caution, and further well-designed randomized clinical trials are required to provide more definitive conclusions.

SUPPLEMENTARY MATERIALS

Supplementary Table 1

Characteristics of the included randomized clinical trials

Supplementary Table 2

Outcomes of the included randomized clinical trials