Nonsurgical Endodontic Retreatment Research Articles

Nonsurgical Endodontic Retreatment of a Cystic Apical Lesion Associated with Root Resorption: A Promising Approach

This case report highlights the successful management of a cystic apical lesion associated with root resorption through nonsurgical endodontic retreatment, utilizing calcium-enriched mixture (CEM) cement as an obturating biomaterial. A 35-year-old woman presented with mild discomfort in the mandibular right first molar (#46), with radiographic evidence of a well-defined radiolucent lesion at the apex of the mesial root. The tooth had a history of previous failed endodontic treatment with poor root canal obturation, indicating internal root resorption. Nonsurgical endodontic retreatment was performed, and the canals were filled/sealed with CEM cement. Follow-up radiographs showed a gradual reduction in the size of the cystic lesion. At 54 months, complete bone healing of the cystic apical lesion was evident. This case report provides clinical evidence supporting the potential efficacy of nonsurgical endodontic retreatment using CEM cement in managing certain cystic apical lesions, offering a promising alternative to traditional surgical enucleation, even in cases with inflammatory root resorption. Further research is needed to validate the long-term efficacy of this approach in larger patient populations.

Nonsurgical endodontic retreatment: A series of four case reports

The primary objective of endodontic treatments or any pulp therapy is to maintain the integrity and health of oral tissues. Endodontic treatments aim to disinfect and shape the root canal system completely and obturate it in 3D to prevent reinfection. Although initial root canal therapy has high success rates, failures can occur. The term ‘retreatment’ denotes a new intervention to retain the tooth in the oral cavity. Nonsurgical endodontic retreatment can preserve previously treated teeth with persistent periapical lesion(s), if the tooth is restorable and periodontally sound, and patient wants to keep it. The clinician and patient should select the treatment with the best long-term outcome. This case series describes endodontically treated teeth that required nonsurgical endodontic retreatment due to inadequate obturation, persistent periradicular lesion and loss of coronal seal.

Effect of the filling technique on the filling removal from oval-shaped canals.

This ex vivo study aimed to evaluate the influence of different filling techniques on the filling removal from oval root canals filled with bioceramic sealer. Thirty-six mandibular incisors with single oval canals were filled with bioceramic sealer following the techniques (n = 12): single-cone, modified McSpadden, or continuous wave of condensation, and scanned by micro-computed tomography (micro-CT). The filling was removed using the Clearsonic ultrasound tip and Reciproc system up to the R40 instrument, and the working time was recorded. The teeth were scanned again by micro-CT. Percentage of remnant volume (mm³) of the filling material, dentin thickness, and root canal transportation were measured. The data was analyzed using parametric and non-parametric tests with a significance level of 5%. It took more time to remove the filling material using the continuous wave of condensation technique (p < 0.05), followed by the modified McSpadden and single-cone techniques. There was no difference (p > 0.05) when comparing the percentage of remaining filling material among the three groups, nor did it among the segments of each tooth. There was also no difference in the analysis of dentin thickness and transportation when comparing the groups (p > 0.05). The filling technique did not influence the amount of remaining filling material, dentin thickness, and transportation. The working time was longer with thermoplastic filling techniques. Endodontic retreatment in teeth filled with bioceramic sealers increases with their use. Several techniques are used to fill the root canals, thus, it is important to know whether the filling technique influences the non-surgical endodontic retreatment.

A 12-month randomized controlled trial to assess the efficacy of revitalization of retreated mature incisors with periapical radiolucency in adolescents

The use of regenrative endodontics is restoring the health status of the root canals of retreated mature teeth is a novel approach. Therefore, the current trial aimed to compare the effectiveness of regenerative endodontic procedures (REPs) to non-surgical root canal retreatment (NS-RCR) in reducing periapical radiolucency over one year for the retreatment of mature incisors with periapical periodontitis. The secondary purpose was to assess clinical success and regain pulp sensibility. A parallel randomized controlled trial, 66 mature incisors with periapical radiolucencies were randomly divided into two equal groups and retreated with either REPs or NS-RCR. At baseline and after 6 and 12 months, teeth were assessed clinically and radiographically using a periapical index (PAI). The Mann–Whitney test was used to analyze nonparametric PAI scores. The Electric pulp test readings were analyzed using the repeated measure analysis of variance (ANOVA). Over the follow-up intervals, there was no significant intergroup difference in the PAI medians, the majority of the teeth displayed a reduction in periapical radiolucency. At the end of the follow-up period, the clinical successes for the REP and NS-RCR groups were 93.9% and 97%, respectively (p = 0.555). Positive pulp sensibility was recorded in 54.54% of cases in the REPs after 12 months. Both approaches showed a comparable diminishing of periapical radiolucencies and equivalent clinical results. A conventional, non-surgical endodontic retreatment may not always be necessary.

Postoperative Pain of Endodontic Re-treatment in Single and Multiple Visits: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Abstract Aim: This systematic review aimed to evaluate the influence of single-visit and multi-visit non-surgical endodontic re-treatments on the incidence, intensity, and duration of postoperative pain and adverse effects. Materials and Methods: A search of the literature was conducted after registration of the study protocols in PROSPERO to find randomized clinical studies assessing postoperative pain in non-surgical endodontic re-treatment conducted during one or more visits in PubMed, Cochrane library, and Scopus databases and EBSCO using a definitive search strategy based on inclusion and exclusion criteria. Using the Cochrane risk of bias method, two independent reviewers determined the studies that were eligible for inclusion, extracted data, and evaluated the quality. Meta-analysis was carried out at wherever appropriate. Results: A total of 827 citations were found by the database search and 16 citations from other sources. Eleven full-text articles were obtained after duplicates were eliminated. Three clinical trials were deemed eligible for inclusion; on qualitative evaluation, two studies showed an unclear risk and one was graded as having a significant high risk of bias. The sample size was significant in only one study, and the other two studies had a smaller sample size. Meta-analysis was performed at 24 h, 48 h, and 7 days. The random-effects model at 24 and 48 h and fixed-effects model after 7 days indicated that there is no significant difference in pain intensity between single-visit and multi-visit re-treatments. Conclusion: The significance of the number of visits on the subsequent pain following the re-treatment procedure was underlined by this current systematic review and meta-analysis. The single visit re-treatment caused less postoperative pain and can be considered based on the clinical scenario.

The incidence and intensity of postoperative pain and Flare-up following the use of three different intracanal medicaments in teeth with posttreatment apical periodontitis: a randomized clinical trial

ObjectivesThis randomized clinical trial aimed to compare the effect of intracanal medicaments on the incidence of postoperative pain and flare-up with posttreatment apical periodontitis (PTAP) of retreatment cases.Materials and methodsOne hundred twenty patients diagnosed with PTAP with single-rooted teeth with single-canal without spontaneous pain or swellings were included and randomly divided into three groups according to the intracanal medicament used. Intracanal medicaments were placed into the root canals following the removal of previous root canal fillings and re-instrumentation. Calcium hydroxide (Ca (OH)2), chlorhexidine gel (CHX), calcium hydroxide and chlorhexidine gel combinations were used as intracanal medicaments. Postoperative pain scores were recorded at 6 and 12 h and 1, 2, 3, 4, 5, 6, and 7 days using a visual analog scale (VAS). Sensitivity on percussion, spontaneous pain, swelling, antibiotic and analgesic requirements of the patients were evaluated during clinical examinations performed postoperatively after 2 and 7 days.ResultsThere were no statistically significant differences between groups in terms of VAS scores following the intracanal medicament application (p > 0.05). However, compared to the patients of 20–34 and 50–65 age groups, greater VAS scores were observed in patients of 35–49 age groups at 12 h, and 3, 4, 7 days (p < 0.05). Flare-up was observed in only one patient in the CHX gel group, and no flare-up was observed in other groups.ConclusionsSimilar postoperative pain incidence in all experimental groups indicates that all three medicaments are clinically acceptable in inter-appointment management of retreatment cases in terms of post-endodontic pain and flare-up.Clinical relevanceIn this randomized clinical trial, three different intracanal medicaments were utilized in nonsurgical endodontic retreatment and their effect on postoperative pain and flare-up incidence was examined. Thus, this study will be a significant contribution in the decision-making during clinical practice; since there are a limited number of prospective clinical trials in the literature about the severity of pain following retreatment procedures including intracanal medicament use.

Evaluation of postoperative pain in endodontic retreatment with apical periodontitis using ozonated 2% chlorhexidine and 0.1% octenidine application: A randomized clinical trial.

This study aimed to evaluate and compare postoperative pain (PP) in single-visit nonsurgical endodontic retreatment (SV NSER) with 2% chlorhexidine (CHX), 0.1% octenidine (OCT) with or without ozone, and 5.25% sodium hypochlorite (NaOCl). In this randomized, parallel, prospective, double-blind, clinical trial, 132 single-rooted, root-filled teeth with symptomatic apical periodontitis (AP) requiring NSER were allocated into six groups randomly (n = 22/group): 2% CHX with NaOCl (CHXH), 2% Ozonated CHX without NaOCl (OCHX), 2% Ozonated CHX with NaOCl (OCHXH), 0.1% OCT with NaOCl (OCTH), 0.1% Ozonated OCT without NaOCl (OOCT), and 0.1% Ozonated OCT with NaOCl (OOCTH). Standard NSER protocol was followed groups were irrigated with 15 ml of ozonated or nonozonated irrigant (CHX/OCT) for 3-5 min with ultrasonic agitation. PP at baseline, after 6, 12, 24, 48 h, and 7 days was recorded using the Visual Analog Scale (VAS). Logistic regression of predictor variables was compared using the Chi-square test. For group-wise and time-wise comparisons, a two-way analysis of variance followed by the post hoc Bonferroni test was carried out. None of the patient-related variables in logistic regression obtained a statistically significant (P > 0.05) role in PP. The VAS score after 6 h was OCHX (4.72) > OOCT (4.42) > CHXH (4.23) > OCTH (3.95) > OCHXH (3.42) > OOCTH (3.21). OOCTH and OCHXH groups demonstrated statistically significant reductions in VAS scores at various time intervals (P < 0.05). SV NSER with ozonated OCT, CHX irrigation, and NaOCl resulted in lesser PP at all time intervals, i.e., 6, 12, 24, 48 h, and 7 days in patients with symptomatic AP.

Nonsurgical Endodontic Retreatment After Failed Apical Surgery

Nonsurgical Endodontic Retreatment After Failed Apical Surgery

Optimizing Non-surgical Endodontic Retreatment: A 3D CBCT Quantification of Root Canal Bioceramic Filling Material Removal

Optimizing Non-surgical Endodontic Retreatment: A 3D CBCT Quantification of Root Canal Bioceramic Filling Material Removal

Do Continuous Rotating Endodontic Instruments Extrude Fewer Apical Debris Than Reciprocating Instruments in Non-Surgical Endodontic Retreatments? A Systematic Review

Background: All endodontic treatment techniques are associated with the extrusion of debris into periradicular tissues through the apex. The extrusion of apical debris can lead to delayed healing or even therapy failure. It is possible to reduce the extrusion into periapical tissues through various approaches. The objective of this systematic review is to evaluate whether, in cases of non-surgical endodontic retreatment, reciprocating instruments cause greater extrusion of debris compared to instruments with continuous rotation. Methods: A search was conducted on PubMed, Ovid MEDLINE, and the Web of Science. The inclusion criterion was in vitro studies comparing apical extrusion in endodontically treated elements using continuously rotating and reciprocating files. Results: The search on scientific databases yielded 164 results, out of which only 16 were eligible for evaluation after screening. Conclusions: The authors of the research included in this review do not agree on the results obtained. Based on the articles analyzed in this systematic review, it remains unclear whether continuous rotation or reciprocating movement of the endodontic instrument can lead to significant differences in apical debris extrusion; it is not possible to provide a clear clinical recommendation regarding the choice of instrument movement for endodontic procedures.

Cone-beam computed tomographic evaluation and fracture resistance of endodontically retreated teeth using hyflex remover, Mtwo, and ProTaper retreatment file systems: An in vitro study

Introduction: One of the important factors contributing to the success of nonsurgical endodontic retreatment is the efficient removal of the obturating material from the root canal space. However, the fracture resistance of the tooth is likely to be affected by this procedure. Therefore, the study envisages assessing residual filling material in the root canals and the tooth’s resistance to fracture postretreatment using different retreatment files. Materials and Methods: Ninety extracted mandibular premolars with one root and a single canal were decoronated, followed by chemo-mechanical preparation, and thereafter, using the lateral compaction method, root canals were obturated. The samples were divided into three groups (n = 30) in accordance with retreatment file systems, namely Hyflex Remover, Mtwo, and ProTaper. All three groups were subjected to the cone-beam computed tomography evaluation to assess remnants of obturating material inside the canals postretreatment, and the same samples were further assessed for fracture resistance, respectively. The collected data were evaluated using the statistical analysis using the Kruskal–Wallis and post hoc Bonferroni tests. Results: There were significant differences in the volume of residual filling among the tested groups in the cervical thirds (P &lt; 0.05). The HyFlex remover file showed the highest fracture resistance (427.30 ± 33.53 N), followed by the Mtwo R (396.90 ± 27.17 N) and ProTaper R (378.50 ± 36.82 N). Conclusion: All the tested nickel-titanium retreatment files performed satisfactorily. Hyflex remover left the least amount of filling material in the cervical third and displayed the highest fracture resistance among the respective groups.

Comparing the Efficiency of Single versus Dual Ultrasonic Devices for Metallic Post Removal in Endodontic Retreatment: A Clinical Study.

Ultrasonic vibration for metallic post removal seems to be a unanimous choice between endodontists and general practitioners for providing the best results and having the highest safety. This study compared the time required by ultrasonic vibration for removing metallic post (MP) when 1 or 2 ultrasonics devices are used. One hundred and fifteen teeth with MPs from 105 patients, indicated for nonsurgical endodontic retreatment were divided into 2 groups according to the number of ultrasonic devices used (G1-1 device) and (G2-2 devices). In G1, the MP was worn with a transmetal bur, alongside the wear of the cement line (around 2 mm deep). Then, an ultrasonic tip attached to an ultrasonic unit, with a power of 100% was activated at the level of the post, with constant water spray at a level of 1 mm above the axial surface of the tooth. The position of the tip was changed between buccal and lingual surfaces every 10 seconds until the MP was removed. In G2 the same procedures were performed as described in G1, but two ultrasonic tips were activated simultaneously at buccal and lingual surfaces until the MP was removed. The vibration time necessary for removing each MP was recorded using a chronometer. The mean time was 131.10±29.68 seconds (mean±standard error of the mean) for MP removal using one ultrasonic device, and 24.86±6.88 seconds for two devices. The time required for MP removal using two ultrasonic devices was significantly less than when using one ultrasonic device (P<0.001). The technique with 2 ultrasonic devices proved to be more efficient than the one using only 1 ultrasonic device.

Comparing the softening effect of three gutta-percha solvents on different types of gutta-percha with different application durations

IntroductionDuring non-surgical endodontic retreatment, gutta-percha (GP) solvents are indispensable in difficult cases when used with mechanical removal, however studies comparing their efficacy against different types of GP are limited. The purpose of this study was to investigate the softening effect of three solvents on the conventional (CGP), cross-linked carrier-based (CLGP), and thermoplasticized (TGP) and compare the effect of time on the softening effect of the solvents. MethodsTested GP were embedded in cuboidal blocks of stone with their upper surfaces exposed (1 mm diameter). Three commercial GP solvents based on D-Limonene (DL), Eucalyptol oil (EO), and orange oil (OO) were added to the exposed GP before an indenter (weight = 1Kg) was applied. Using a digital camera, the indentation depth was measured (mm) directly after applying the solvent and indenter (T = 0), and after 1, 2, and 3 min of application (T = 1,2,3). The means of indentation depth were calculated and compared using a two-way analysis of variance and Tukey’s post-hoc test to assess the effect of the types of solvent, GP for each application duration, and Friedman’s test to evaluate the effect of application duration on the softening effect of solvents. ResultsThe type of GP (F = 261.43, p < 0.001), type of solvent (F = 3.57, p = 0.015), and application duration (F = 53.088, p < 0.001) were all found to significantly affect GP softening. DL exhibited the highest and only significant effect on CGP after 1 min (p < 0.05), while OO had the only significant effect against CLGP when applied for at least 2 min (p < 0.05). Both OO and EO had significant softening effects on TGP instantly or after 1 min of application, respectively. ConclusionsThe results of this study revealed that the softening effect of GP solvents varies depending on their type, their application duration, and the type of GP.

Influence of sealer type on treatment outcome of teeth with apical periodontitis: a systematic review.

The purpose of this article was to Evaluate the influence of sealer on the outcome of non-surgical endodontic treatment or retreatment of permanent teeth with apical periodontitis (PROSPERO registration: CRD42020205951). A systematic review of original clinical studies was carried out following PRISMA guidelines to answer whether the type of sealer used in endodontic treatment or retreatment influences the repair of apical periodontitis determined by clinical and radiographic parameters. Electronic searches were performed in PubMed, Embase, Web of Science, Scopus, and the Cochrane Library database, until May 2023. Gray literature and a hand search of reference lists were also performed. The risk of bias was assessed using Cochrane RoB2 for randomized trials and the Newcastle-Ottawa Scale (NOS) for prospective and retrospective cohort and case-control studies. Among 1046 studies, a total of 819 were selected by title and abstract, resulting in 23 for full-text review. In total, 11 studies met the inclusion criteria (1467 patients/teeth with apical periodontitis). The quality assessment using RoB2 included five randomized control trials, of which four had medium risk and one had a low risk of bias. According to the NOS scale, five studies were classified as low risk and one study was considered as medium risk of bias. The sealer type and obturation techniques varied, and the mean follow-up time was 3.7 years. Most studies used two-dimensional radiographic criteria to assess the treatment outcome sealers and not cements. Eight studies did not find significant differences when comparing cements. The healing rates ranged from 56.7% to 90%. The results of this review support that the current endodontic sealers do not seem to influence the treatment outcome of permanent teeth with apical periodontitis. Although the studies had medium and low risk of bias, the results should be interpreted with caution. More randomized studies of long-term outcomes comparing filling materials are needed to strengthen this claim and allow for a meta-analysis.

Resolution of Apical Periodontitis-induced Mental Nerve Paresthesia Through Nonsurgical Endodontic Retreatment: A Case Report

Paresthesia is a potential consequence of unsuccessful root canal treatment. Persistent infection resulting in apical periodontitis may enlarge sufficiently to involve the mental neurovascular bundle. The case presented in this report was referred for endodontic evaluation with a chief complaint of discomfort on mastication and persistent numbness of the lower left lip. Clinical and radiographic evaluation revealed incomplete primary endodontic treatment of the left mandibular second premolar with complex internal anatomy. The untreated root canal system resulted in the progression of apical periodontitis involving the left mental neurovascular bundle as confirmed by cone-beam computed tomography imaging. Nonsurgical root canal retreatment was performed over 2 visits. At the 3-year follow-up visit, the paresthesia had resolved with return of normal sensation. Nonsurgical endodontic retreatment may be sufficient to allow healing of large periapical lesions and resolve complications including paresthesia without the need for surgical intervention.

Combined Effect of Mineral Trioxide Aggregate and Customized Glass Fiber Post in Nonsurgical Endodontic Retreatment Teeth at Esthetic Zone: A Case Report

Combined Effect of Mineral Trioxide Aggregate and Customized Glass Fiber Post in Nonsurgical Endodontic Retreatment Teeth at Esthetic Zone: A Case Report

Rotary Systems for Root Canal Gutta-percha Removal: A Review

Gaining a predictable outcome in endodontics is complicated by handling an endodontically treated. Compared to primary root canal therapy, non-surgical endodontic retreatment typically entails the removal of previous root filling materials. This process may be necessary to enable access to contaminated canal space for recleaning and to remove obturation materials that may have been contaminated by marginal penetration of microorganisms and microbial toxins. The achievement of patency at the canal terminus and the extension of cleaning as close as possible to the apical terminus have been identified as healing prognostic criteria. Gutta-percha (GP) is the current mainstay material utilised as an endodontic filling material, capable of performing comprehensive, three-dimensional sealing of the treated root canal system in a highly effective manner with considerable physical durability. Interestingly, since its initial discovery in the 17th century, GP remains to this day the ideal obturation material used across, in essence, all dental clinics globally due to its material properties and versatility for use in conjunction with sealer compounds. The development of GP removal systems that can manage to remove GP in its entirety from root canals during non-surgical retreatment procedures is currently highly desirable for dental practices. This literature review investigated this current research niche and scrutinised two prevalently utilised rotary systems – Edgefile-XR and the XP-Endo shaper systems.

The Effect of Number of Visits, Use of Solvent and Gutta-percha Removal Technique on Postoperative Pain following Nonsurgical Endodontic Retreatment; A Systematic Review and Meta-analysis.

The nonsurgical endodontic retreatment (NERT) is the first choice of dental ministration when primary/initial endodontic treatment fails. The present study aimed to investigate the presence of postoperative pain (POP) after NERT in permanent asymptomatic teeth as well as possible factors associated with POP. A comprehensive search of literature was performed in Pubmed/MEDLINE, Embase, Scopus and Web of Science databases, up to January 2023; including randomized clinical trials and prospective studies. The risk of bias was assessed with RoB 2.0 and ROBINS-I tools. Subgroups analyses were conducted to evaluate the differences in the incidence or level of POP between the number of visits, the use/not use of solvent, the removal technique of gutta-percha, and the period of POP analysis. Mean differences and confidence intervals (CI) of 95% were used as measures of effect, and meta-regression was used along with subgroup analysis. The certainty of evidence was assessed using GRADE, and the probability value of <0.05 was considered significant. Twenty-four studies were selected, with thirteen included in the meta-analysis. There was a statistical difference between the incidence of POP after 24 h (95% CI, 0.28 to 0.52) and one week (95% CI, 0.02 to 0.13) from the endodontic retreatment (P<0.01). However, there was no statistical difference between different techniques, number of visits and use of solvent (P>0.05) in the same period. In addition, the certainty of evidence was very low. Post-operative pain is a common response to NERT, independent of the retreatment technique(s) applied, number of visits and use of solvent(s); with very low certainty of evidence as well as low risk of bias. Moreover, the current analysis showed a (very) serious risk of inconsistency and imprecision. However, POP was significantly reduced within 1 week of the NERT.

The Effect of Reciprocating Instrument and Root Canal Filling Techniques on Post-operative Pain in Retreatment: A Prospective Clinical Study.

The aim of this prospective clinical study was to assess the effect of different instruments and root canal filling techniques on post-operative pain in single visit of endodontic retreatment. Forty five patients (18-65 yrs old) who needed non-surgical endodontic retreatment in mandibular premolar or molar teeth without any symptoms were included in this study. The teeth were randomly assigned into 3 groups of 15 teeth, according to the instrumentation and filling techniques: hand files with lateral compaction (group 1), Reciproc with lateral compaction (group 2), Reciproc with continuous wave compaction technique (group 3). Retreatments were performed in a single visit and post operative pain was assesed at 4 intervals; 24, 48,72 hours and 7 days. All data were analyzed using One way Anova, Chi-square and Fisher's Exact test and the significance level was set to (p≤0,05). No statistically significant difference was found among the groups in relation to post-operative pain (p>0.05). Although the intensity of post-operative pain was decreased over the time in all groups, significant difference was found only in Reciproc groups (p<0.05). However, no pain was found in any patient at the end of 7 day. Also, statistically significant difference was found between pain intense and periapical index in 24 and 72 hours (p<0.05). In the present study, the intensity of post-operative pain was not found to be related to instrumentation or filling techniques in retreatment cases. The intensity of pain could be related to periapical index of the tooth. (EEJ-2022-09-117).

Comparison of Endodontic Failures between Nonsurgical Retreatment and Endodontic Surgery: Systematic Review and Meta-Analysis with Trial Sequential Analysis.

Background and Objectives: In the presence of a persistent endodontic lesion or endodontic failure, the alternative for the recovery of the dental element is endodontic retreatment or endodontic surgery, which consists in the surgical removal of the root apices with retrograde closure of the endodontium. The objective of this systematic review and meta-analysis was to provide an updated value of the Risk Ratio between the two types of treatment in order to offer to clinicians who propose a non-surgical endodontic retreatment or an endodontic surgery a direct comparison. Materials and Methods: The revision was performed according to PRISMA indications: three databases (PubMed, Scopus and Cochrane register) were consulted through the use of keywords relevant to the revision topic: surgical endodontic retreatment, endodontic retreatment, apicoectomy. This search produced 7568 records which, after eliminating duplicates and applying the inclusion and exclusion criteria, resulted in a total of seven included articles. The meta-analyses were conducted by applying fixed-effects models, given the low percentage of heterogeneity. In addition, trial sequency analysis (TSA) was performed for the analysis of the statistical power of the results and GRADE for the quality of the evidence. Results: The results of the meta-analyses’ data report an aggregate risk ratio (RR) between non-surgical endodontic retreatment and surgical endodontic retreatment of: 1.05 [0.74, 1.47] at one year of follow-up; RR 2.22 [1.45, 3.41] at two years of follow-up; an RR 1.08 [0.73 1.62] for a follow-up period of 3–4 years; and an RR 0.92 [0.53, 1.61] for a follow-up period of 8–10 years. Conclusions: The results of the present meta-analysis show that in the long term, the risk of failure is identical for the two groups, and there is only a slightly higher risk of failure for non-surgical endodontic retreatments, when only two years of follow-up are considered.