Long-term Outcomes and Prognostic Factors in Surgical Endodontic Retreatment: A Retrospective Cohort Study

Long-term Outcomes and Prognostic Factors in Surgical Endodontic Retreatment: A Retrospective Cohort Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Long-term Outcomes and Prognostic Factors in Surgical Endodontic Retreatment: A Retrospective Cohort Study Saeed Asgary, Maryam Hosseini, Alireza Akbarzadeh Baghban This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7501598/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 23 Feb, 2026 Read the published version in BMC Oral Health → Version 1 posted 12 You are reading this latest preprint version Abstract Background Persistent apical periodontitis following failed nonsurgical endodontic treatment presents significant clinical challenges. This study evaluated the long-term outcomes and prognostic factors associated with surgical retreatment using calcium-enriched mixture (CEM). Methods In this retrospective cohort study (STROBE-compliant), 197 teeth from 169 patients underwent surgical retreatment at a tertiary center between 2011 and 2024. Inclusion required documented persistent apical periodontitis unresponsive to prior orthograde endodontic therapy and a minimum radiographic follow-up of 6 months. A standardized microsurgical protocol was followed, including root-end resection, ultrasonic root-end preparation, and root-end filling with CEM cement by a single endodontist. Treatment outcomes were assessed using composite clinical and radiographic criteria. Kaplan–Meier analysis was used to estimate survival probabilities, and Cox proportional hazards regression was applied to evaluate associations between clinical variables and treatment outcomes. Results The mean follow-up duration was 45.2 ± 36.5 months. The overall success rate was 94.9% (187/197 teeth). Failure-free survivals were 96.4%, 92.7%, and 87.3% at 1, 3, and 5 years, respectively. Multivariate analysis identified systemic disease as the sole significant predictor of failure (HR = 5.87; 95% CI: 1.52–22.68; p = 0.010). Tooth-related factors (lesion size, crown-root ratio, and root-end preparation depth) and demographic variables showed no significant associations. Intra-observer agreement was excellent (κ = 1.00; ICC = 0.83). Conclusions CEM cement-based surgical retreatment achieved 94.9% long-term success. Patients with systemic diseases exhibited a 5.87-fold higher failure risk, highlighting the critical role of medical status in prognostic assessment. Apical periodontitis CEM cement Dental radiography Endodontics Calcium derivative Mineral trioxide aggregate Microsurgery Introduction Persistent apical periodontitis represents a significant clinical challenge in endodontics, often necessitating surgical intervention when nonsurgical endodontic retreatment is unfeasible or unsuccessful ( 1 ). Endodontic microsurgery has emerged as the definitive tooth-preserving approach for such cases, particularly when anatomical complexities, persistent cysts, or extraradicular infections preclude orthograde management ( 2 ). The evolution from traditional apicoectomy to contemporary endodontic microsurgery, driven by microsurgical instruments, ultrasonic retro-tips, and high-magnification optics, has markedly improved outcomes, with modern success rates exceeding 90% ( 3 , 4 ). The efficacy of endodontic microsurgery hinges critically on precise surgical technique and the biocompatibility of root-end filling materials. Calcium-enriched mixture (CEM) cement, a bioactive material with demonstrated sealing capacity and osteogenic potential, offers theoretical advantages over conventional options ( 5 ). Similar to other calcium silicate-based cements, such as mineral trioxide aggregate, it exhibits favorable biological properties. While short-term studies report favorable surgical outcomes with CEM ( 6 , 7 ), robust long-term evidence remains scarce, limiting evidence-based clinical adoption. Prognostic assessment in endodontic microsurgery is further complicated by heterogeneous methodologies across existing literature ( 8 , 9 ). Factors such as preoperative lesion size, tooth position, restorative status, and systemic health have been inconsistently examined, often within underpowered cohorts or studies lacking standardized protocols. Critically, most investigations suffer from methodological limitations: multi-operator variability, short follow-up durations prone to regression-to-mean bias, and inconsistent application of microsurgical materials/technologies ( 10 – 12 ). This knowledge gap underscores the need for longitudinal, technique-standardized analyses. We therefore designed this 13-year retrospective cohort study with dual objectives: 1) to quantify long-term success rates of CEM-based endodontic microsurgery using composite clinical-radiographic criteria, and 2) to identify prognostic factors among demographic, tooth-related, and systemic variables, including age, smoking status, medical history, lesion characteristics, crown-root ratio, and root-end preparation depth. The null hypothesis posited that no clinical or radiographic variables would significantly influence treatment outcomes. By addressing these aims through a single-operator, STROBE-compliant design with blinded outcome assessment, this study aims to establish evidence-based benchmarks for CEM cement in surgical endodontics while refining prognostic stratification in medically complex patients. Materials and Methods Study Design This retrospective cohort study was conducted at Mehr Dental Clinic, Tehran, Iran. The source population included all patients who underwent surgical endodontic retreatment at the clinic between January 2011 and January 2024. The study cohort comprised patients who received surgical endodontic retreatment due to persistent apical periodontitis following either unsuccessful nonsurgical endodontic retreatment or failed initial root canal therapy. This study was approved by the Research Institute for Dental Sciences (RIDS), Shahid Beheshti University of Medical Sciences (Grant No. IR.SBMU.RIDS.43014868). Ethical clearance was obtained from the RIDS Ethics Committee (Approval No. IR.SBMU.DRC.REC.1404.046). The protocol adhered to the Declaration of Helsinki. Written informed consent was obtained from all patients for clinical treatment, while the institutional ethics committee granted a waiver of consent for retrospective review of de-identified patient records. The study design and reporting followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines ( 13 ). Data Source and Collection A single qualified examiner (SMH), blinded to the study’s specific hypotheses, systematically extracted preoperative, intraoperative, and postoperative clinical and radiographic data for each eligible patient/tooth encounter from the clinic’s comprehensive electronic health record system (Dental Information System; Tarasheh Hooshmand Novin, Tehran, Iran). Data extraction was conducted according to a predefined protocol to ensure accuracy and consistency across all cases. Eligibility Criteria All surgical procedures were performed by a single board-certified endodontist (SA) to minimize operator-related variability. Inclusion Criteria- Teeth were eligible for inclusion if all of the following criteria were met: Diagnosis : Presence of persistent apical periodontitis of endodontic origin, confirmed both radiographically (e.g., Periapical Index [PAI] score ≥ 3) and clinically (e.g., presence of symptoms or sinus tract). Eligible cases included those in which: nonsurgical retreatment was deemed clinically unfeasible (e.g., presence of a post/core, complex canal anatomy precluding negotiation, separated instrument extending beyond the apex, or non-negotiable ledges), OR previous nonsurgical endodontic treatment (initial therapy or retreatment) had failed, as evidenced by persistent or progressive apical periodontitis. Data Completeness : Availability of comprehensive preoperative documentation, including diagnostic radiographs, clinical examination findings, and medical/dental history, as well as postoperative records comprising documented clinical assessments and at least one periapical radiograph obtained ≥ 6 months after the surgical procedure. When multiple follow-up radiographs were available, the most recent image meeting the minimum 6-month requirement was used for primary outcome assessment. Restorative and Periodontal Status : At the time of surgery, the treated tooth exhibited: an adequate and well-sealed coronal restoration (functionally intact and without clinical or radiographic evidence of marginal leakage), AND periodontal health, defined as probing depths ≤ 3 mm on all surfaces and absence of clinical signs of periodontitis (e.g., bleeding on probing, suppuration, or mobility greater than grade 1). Exclusion Criteria - Teeth were excluded if any of the following conditions were present: Surgical History : Prior surgical endodontic intervention on the same tooth (i.e., cases requiring re-surgery). Specific Pathologies : Evidence of cemental tears, root perforations (excluding iatrogenic perforations adequately managed during the index surgery), or cervical external root resorption identified either preoperatively or intraoperatively. Periodontal Disease : Clinical/radiographic diagnosis of chronic periodontitis affecting the involved tooth, or confirmed vertical root fracture. Systemic Conditions : Presence of uncontrolled systemic diseases known to impair healing (e.g., immunosuppressive therapy, prior head or neck radiotherapy). Insufficient Data : Incomplete preoperative/postoperative documentation, or follow-up radiographs obtained less than 6 months after the surgical procedure. Treatment Protocols All surgical endodontic retreatments were performed by a single board-certified endodontist (SA) following a standardized microsurgical protocol under strict aseptic conditions. Written informed consent was obtained from all patients after a detailed explanation of the procedure, potential risks, benefits, and alternative treatment options. Per current clinical guidelines, all patients received preoperative medication consisting of ibuprofen 400 mg and a 0.2% chlorhexidine gluconate mouth rinse. Local anesthesia was achieved with 2% lidocaine containing 1:80,000 epinephrine (DarouPakhsh, Tehran, Iran) administered via appropriate nerve block and/or infiltration techniques. After anesthesia, a full-thickness mucoperiosteal flap was reflected to provide optimal surgical access. A flap design (submarginal, triangular, rectangular, or papilla-base-preserving) was selected based on tooth location, access requirements, and esthetic considerations, with meticulous care to minimize papillary trauma. An osteotomy was performed to create a conservative bony window (~ 3–5 mm) directly over the root apex using sterile high-speed surgical burs under copious irrigation. Bone removal was minimized to preserve structural integrity. Curettage of all pathological periradicular tissues, including granulomatous and cystic lesions, was performed with sharp curettes. Root-end resection involved the removal of approximately 2–3 mm of the root apex perpendicular to the long axis of the tooth, using a fine tapered fissure bur under continuous irrigation, with the bevel angle kept to a minimum. Root-end inspection under magnification ensured the identification of isthmuses, accessory canals, or missed canals. A class I root-end cavity (~ 3 mm deep) was prepared at the center of the resected surface using an ultrasonic retrotip (e.g., Joya Electronic, Tehran, Iran) operated at low power under constant irrigation. Root-end filling was performed with CEM cement (BioniqueDent, Tehran, Iran), prepared according to the manufacturer’s instructions and mixed to an appropriate consistency. The cement was incrementally placed into the cavity using micro-pluggers, condensed to achieve a dense, void-free fill, and any excess material was removed. A periapical radiograph confirmed complete resection, preparation, and filling/sealing. The surgical site was thoroughly irrigated with sterile saline, and meticulous hemostasis was maintained throughout. The flap was precisely repositioned and secured with non-resorbable 4 − 0 silk sutures, followed by gentle digital pressure with moist gauze for at least three minutes to improve adaptation and minimize coagulum thickness. Postoperative care included detailed written and verbal instructions on analgesic use, antimicrobial mouth rinse, soft diet recommendations, and oral hygiene precautions. Sutures were removed 5–7 days post-surgery. Radiographic Assessment and Technique Digital periapical radiographs were obtained preoperatively, immediately postoperatively to verify root-end filling placement, and at all subsequent follow-up visits using a standardized protocol to ensure consistency and optimal diagnostic quality. Radiographs were acquired employing a strict paralleling technique with a Rinn XCP beam-guiding device (FPS 3000, Dentsply Sirona, India). All exposures were performed using a single Soredex X-ray unit (Tuusula, Finland) operating at 60 kVp and 7.5 mA. Phosphor Storage Plates (PSPs; Digora Optime, Soredex, Tuusula, Finland) of appropriate size served as image receptors. Exposure times were standardized according to tooth type and anatomical region based on initial phantom calibrations to optimize image quality while minimizing radiation dose. PSPs were processed immediately after exposure using the Digora Optime scanner (Soredex) following the manufacturer’s instructions. Radiographic evaluations were conducted under strictly controlled viewing conditions. Images were displayed on a high-resolution, DICOM-calibrated 34-inch HP Envy curved monitor (resolution: 3440 × 1440 pixels; HP, Palo Alto, CA, USA) in a dedicated, dimly lit room. All radiographic assessments were performed by a single blinded evaluator (MH), unaware of clinical data, patient identifiers, and surgical details. Before the study assessment, the examiner underwent rigorous calibration using a separate set of 50 standardized periapical radiographs not included in the study sample. Inter- and intra-examiner agreement were quantified using Cohen’s Kappa (κ) statistic, with values ≥ 0.75 indicating substantial to excellent reliability. Results of the reliability assessment are presented in the Results section. Data Collection All data were extracted from electronic health records using a standardized case report form and entered into a Microsoft Excel database (Version 2016; Microsoft, Redmond, WA, USA). The following variables were systematically recorded: Patient-Related Factors : Age (years; continuous), sex (male/female), medical history categorized by ASA classification (ASA I: healthy; ASA II: mild systemic disease; ASA III and above: uncontrolled conditions), and smoking status (never, former, or current, with pack-years quantified for current smokers). Tooth-Related Factors : Tooth type (anterior, premolar, or molar), arch location (maxillary or mandibular), root morphology (single- or multi-rooted, noting curvatures > 10°), presence and type of intracanal post (absent or present; categorized as cast metal, prefabricated, or fiber posts), coronal restoration type (direct composite, indirect crown, or temporary), crown-root ratio (calculated as crown length to root length, categorized as ≤ 1 or > 1), and preoperative periodontal status including probing depths and mobility grade. Treatment-Related Factors : Preoperative lesion size measured in millimeters (mm) on digital radiographs using standardized software, root resection length (mm) measured intraoperatively, root-end preparation depth (mm) confirmed during surgery, and follow-up duration in months calculated from the date of surgery. Outcome-Related Factors : Clinical success or failure recorded as a binary variable, radiographic healing categorized according to both PAI and time-to-failure in months for survival analysis. Outcome Evaluation Success Treatment was considered successful when both clinical and radiographic parameters were within normal limits. Radiographic success was defined as PAI scores of 1, or stable/slightly widened periodontal ligament space (PAI 2–3) with evidence of healing and no clinical symptoms ( 14 ). Failure Clinical failure was defined by the presence of persistent postoperative pain, tenderness to percussion or palpation, swelling, sinus tract formation, or irreparable tooth fracture. Radiographic failure included PAI scores of 4 or 5 (indicating apical radiolucency), or unchanged radiolucent lesions. For multirooted teeth, the root with the poorest radiographic prognosis determined the overall radiographic outcome of the tooth. Follow-up duration was calculated from the time of surgical intervention. In cases of failure, the end of the observation period was defined as the date when failure was first documented clinically or radiographically, whichever occurred earlier. Sample Size calculation This retrospective cohort utilized a census sampling approach encompassing all eligible cases meeting inclusion criteria treated between January 2011 and January 2024. No formal a priori sample size calculation was performed due to the exhaustive sampling design. Post hoc power analysis confirmed > 85% power to detect clinically significant associations (HR ≥ 2.0) at α = 0.05 using observed event rates. Statistical Analysis Descriptive and inferential statistical methods were employed. In addition to calculating mean, standard deviation, and dispersion for quantitative variables and frequency distributions for qualitative ones, the Kaplan–Meier curves and the log-rank test were used to assess the univariate effects of predictor variables. The Cox proportional hazards model was applied to evaluate the simultaneous effects of multiple independent variables on treatment success. Additionally, multiple logistic regression was utilized. For quantitative data, an intraclass correlation coefficient (ICC) of 0.75 or higher was considered acceptable, based on Rosner and Cohen's criteria. For qualitative data, a kappa value of 0.6 or higher was deemed acceptable. Statistical analyses were performed using IBM SPSS Statistics for Windows, Version 21.0 (IBM Corp., Armonk, NY, USA). A p-value < 0.05 was considered statistically significant. Results A total of 197 teeth from 169 patients met the inclusion criteria for this retrospective cohort study. The mean duration of follow-up was 45.2 ± 36.5 months. The Median follow-up duration was 34.0 months (IQR: 58), ranging from 6 to 144 months. The mean patient age was 47.8 ± 11.8 years. The cohort included 55 males (32.5%) and 114 females (67.5%). In terms of tooth type, 82 anterior teeth (41.6%), 59 premolars (30.0%), and 56 molars (28.4%) were treated. Most treated teeth were located in the maxilla (92.4%, n = 182), with only 15 teeth (7.6%) located in the mandible. The overall treatment success rate was 94.9% (187 out of 197 cases), with a 5.1% failure rate (10 out of 197). However, these outcomes reflect the expertise of a single surgical specialist in a tertiary referral center and should not be generalized to non-specialized clinical settings. Reliability analysis showed excellent intra-observer agreement. For categorical variables related to healing status, Cohen’s Kappa was 1.00 (95% CI: 1.00–1.00). For continuous variables such as lesion size, the intraclass correlation coefficient (ICC) was 0.83 (95% CI: 0.72–0.90), indicating strong measurement reliability. Kaplan–Meier survival analysis revealed cumulative success probabilities of 96.4% at 1 year (95% CI: 93.1–98.2), 92.7% at 3 years (95% CI: 88.0–95.6), and 87.3% at 5 years (95% CI: 80.9–91.7). In the Cox proportional hazards regression model, adjusted for clinically relevant variables, only the patient's medical history demonstrated a statistically significant association with treatment failure (Table 1 ). Table 1 Success rates analyzed for potential prognostic factors Variable Success Failure p Value n % n % Age N/A N/A N/A N/A .056 Lesion size N/A N/A N/A N/A .413 CCRR N/A N/A N/A N/A .920 Root-end preparation depth N/A N/A N/A N/A .230 Gender Male 52 94.5% 3 5.5% .751 Female 107 93.8% 7 6.2% Smoker yes 6 85.7% 1 14.3% .300 No 181 95.3% 9 4.7% Tooth type Anterior 80 97.6% 2 2.4% .412 Premolar 55 93.2% 4 6.8% Molar 52 92.9% 4 7.1% Jaw Maxilla 172 94.5% 10 5.5% .496 Mandible 15 100% 0 0 Tooth number 1 37 97.4% 1 2.6% .946 2 38 97.4% 1 2.6% 3 5 100% 0 0 4 15 93.8% 1 6.3% 5 39 92.9% 3 7.1% 6 51 92.7% 4 7.3% 7 2 100% 0 0 Post None 87 94.6% 5 5.4% .503 Pre-fabrication 51 98.1% 1 1.9% Casting 31 88.6% 4 11.4% Amalgam-post 18 100% 0 0 Restoration Amalgam 20 95.2% 1 4.8% .865 Composite resin 74 96.1% 3 3.9% Crown 86 93.5% 6 6.5% Bridge 6 100% 0 0 Restorative Surfaces One 29 93.5% 2 6.5% .899 Two 32 97% 1 3% Three 6 100% 0 0 Build up 27 96.4% 1 3.6% Medical history ASA I 147 97.4% 4 2.6% .010 ASA II and above 37 86% 6 14% CCRR, clinical crown-to-root ratio Tooth number : FDI groups Discussion This 13-year retrospective cohort study demonstrated a remarkably high long-term success rate (94.9%) for surgical endodontic retreatment using CEM cement. This outcome exceeds historical success rates associated with conventional root-end filling materials, such as amalgam or IRM ( 15 ), and aligns with more recent data on bioceramics, including a 91.6% four-year success rate for MTA reported by Kim et al. ( 16 ). The superior performance of CEM cement is likely attributable to its unique bioactive properties. Upon hydration, CEM forms hydroxyapatite and continuously releases calcium and phosphate ions, which stimulate osteoblastic differentiation and cementogenesis ( 5 , 17 ). These mechanisms promote a biologically favorable periapical environment and contribute to consistent healing. Importantly, systemic disease emerged as the sole significant predictor of treatment failure, with affected patients demonstrating a nearly six-fold increased risk compared to systemically healthy individuals (HR = 5.87), and a failure rate of 14% versus 2.6%. This is consistent with the findings of Segura-Egea et al. ( 18 ), who reported a higher prevalence of periapical radiolucencies in root-filled teeth among diabetic patients. The biological plausibility of this association is well established. Hyperglycemia reduces osteoblast activity through the accumulation of advanced glycation end-products (AGEs)( 19 ), while chronic systemic inflammation alters matrix metalloproteinase/tissue inhibitor balance (MMP/TIMP), delaying bone remodeling ( 20 ). Moreover, immunosuppressive states impair host bacterial clearance, especially in areas of residual microleakage. These mechanisms underscore the importance of comprehensive medical evaluation in treatment planning, particularly for medically compromised individuals undergoing endodontic surgery. The exceptional treatment outcomes observed in this study likely reflect the synergistic influence of advanced microsurgical techniques, careful case selection, and the use of modern bioactive materials. All procedures were performed using ultrasonic root-end preparation, which has been shown to enhance biofilm removal and create well-adapted root-end cavities with superior sealing geometry. The consistent use of CEM cement, characterized by hydrophilic expansion and bioactive sealing capacity, further contributed to apical seal integrity and periapical tissue regeneration ( 5 , 21 ). Additionally, the inclusion criteria ensured that only structurally and periodontally favorable teeth (e.g., crown-root ratio ≤ 1, intact periodontal attachment) were treated, which likely eliminated confounding anatomical risk factors. Interestingly, lesion size was not significantly associated with treatment failure in this cohort, contrasting with prior findings such as those of Weissman et al., who reported poorer outcomes for large periapical lesions ( 22 ). This discrepancy may be explained by the exclusion of teeth with compromised periodontal support and poor crown-root ratios in the present study, suggesting that lesion size alone may not be a reliable predictor of failure when favorable anatomic conditions are preserved. Moreover, the 100% success rate observed in mandibular teeth, despite their known anatomical and surgical challenges, highlights the role of surgical expertise and meticulous flap design in optimizing access and healing in these complex cases. In our study, root-end preparation depth did not show a statistically significant association with treatment failure. However, this contrasts with previous literature emphasizing its importance for achieving a hermetic apical seal ( 1 ). Notably, all cases in our cohort received a minimum of 3 mm root-end preparation ( 23 ), often exceeding this threshold, in line with contemporary microsurgical protocols. This consistent application of adequate root-end preparation depth likely minimized variability and ensured optimal sealing, contributing to the overall high success rate observed. Several methodological strengths support the reliability of these findings. All procedures were performed by a single endodontic microsurgeon with 15 + years of dedicated microsurgical experience in a tertiary referral center, eliminating inter-operator variability and ensuring technical consistency. Radiographic healing was independently evaluated by a blinded examiner using the Periapical Index, demonstrating strong intra-observer agreement (κ = 1.00, 95% CI: 1.00–1.00). The extended mean follow-up period of 3.8 years allowed for the detection of delayed failures, enhancing outcome validity. However, the single-surgeon design, while minimizing variability, introduces expertise bias; these outcomes reflect the proficiency of a highly specialized surgeon and are not generalizable to non-specialist settings, where results may differ due to training, equipment, and case-selection factors. Future multicenter studies involving operators with varying expertise are essential to validate broader applicability. Additional limitations include the retrospective design, limiting control over confounding variables; aggregation of systemic diseases, precluding condition-specific prognostic analysis; and reliance on 2D radiography, which likely underestimated true healing by missing buccal/lingual defects and volumetric changes ( 24 , 25 ). In clinical terms, these findings reaffirm the importance of thorough preoperative medical evaluation, particularly for identifying patients with systemic conditions that may impair healing and increase failure risk. Lesion size should not be considered a contraindication to surgical retreatment when periodontal integrity and structural support are adequate. Most importantly, this study reinforces the role of CEM cement as an effective bioceramic root-end filling material, supporting its continued use as a viable/efficacious option in endodontic microsurgery. Conclusions Surgical endodontic retreatment with CEM cement demonstrated a 94.9% success rate over a mean follow-up of 45 months, reflecting favorable outcomes in a specialized microsurgical setting. Systemic health status emerged as the sole significant predictor of treatment failure, underscoring the necessity for preoperative risk stratification and individualized follow-up protocols. Neither lesion size nor other traditional prognostic factors correlated with failure within this cohort, suggesting that stringent case selection and microsurgical standards may mitigate these risks. While CEM cement showed clinical effectiveness as a root-end biomaterial in this context, these outcomes reflect expertise-specific conditions and warrant validation through multicenter studies encompassing diverse operator experience levels. Declarations Funding: This study was supported by the Research Institute for Dental sciences (RIDS), Shahid Beheshti University of Medical Sciences (Grant No. IR.SBMU.RIDS.43014868). Clinical trial number: Not applicable Human Ethics and consent to participate declaration: Ethical clearance was obtained from the RIDS Ethics Committee (Approval No. IR.SBMU.DRC.REC.1404.046). The protocol adhered to the Declaration of Helsinki. Written informed consent was obtained from all patients for clinical treatment, while the institutional ethics committee granted a waiver of consent for retrospective review of de-identified patient records. Consent to Publish declaration: Not applicable References Setzer F, Harley M, Cheung J, Karabucak B. 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Cite Share Download PDF Status: Published Journal Publication published 23 Feb, 2026 Read the published version in BMC Oral Health → Version 1 posted Editorial decision: Revision requested 22 Oct, 2025 Reviews received at journal 21 Oct, 2025 Reviewers agreed at journal 11 Oct, 2025 Reviews received at journal 10 Oct, 2025 Reviewers agreed at journal 10 Oct, 2025 Reviews received at journal 23 Sep, 2025 Reviewers agreed at journal 20 Sep, 2025 Reviewers invited by journal 14 Sep, 2025 Editor invited by journal 12 Sep, 2025 Editor assigned by journal 11 Sep, 2025 Submission checks completed at journal 11 Sep, 2025 First submitted to journal 31 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7501598","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":518032595,"identity":"4ccd614f-9253-453c-98e6-9b30b99cc915","order_by":0,"name":"Saeed Asgary","email":"","orcid":"","institution":"Shahid Beheshti University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Saeed","middleName":"","lastName":"Asgary","suffix":""},{"id":518032596,"identity":"4936c38e-3ace-4bbd-9b28-692c69ab6a89","order_by":1,"name":"Maryam Hosseini","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9UlEQVRIiWNgGAWjYBCDBAYG5oMPPgBZbOzEa2FLNpwB0sJMvBYeM2EeEJOQFt32s88kfuYw5DGw95gx2/zaJs/HzMD44WMObi1mZ9LNJHu3MRQz8Bwre5zbd9uwjZmBWXLmNjxaDqSxSfBuY0hskEjebpzbc5sRqIWNmReflvPP2CT/grTIPzCTtuy5bU9Yy400NmmILSxm0gw/bicSoeUZs7XsNonENp60ZMPehtvJbcyMzfj9cj6N8ebbbTaJ/eyHDz748ee27fz25oMfPuLRAgQsEgwMEgxsICZjG5hswKseCJg/INh/CCkeBaNgFIyCkQgA1ZBNAtqEhqgAAAAASUVORK5CYII=","orcid":"","institution":"Shahid Beheshti University of Medical Sciences","correspondingAuthor":true,"prefix":"","firstName":"Maryam","middleName":"","lastName":"Hosseini","suffix":""},{"id":518032597,"identity":"c99ce637-e9ef-45bb-98e4-69fb0cf31a2a","order_by":2,"name":"Alireza Akbarzadeh Baghban","email":"","orcid":"","institution":"Shahid Beheshti University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Alireza","middleName":"Akbarzadeh","lastName":"Baghban","suffix":""}],"badges":[],"createdAt":"2025-08-31 15:38:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7501598/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7501598/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12903-026-07945-z","type":"published","date":"2026-02-23T15:57:04+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":91825848,"identity":"6312f606-eb23-47bc-8a09-135949b9a8f7","added_by":"auto","created_at":"2025-09-22 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08:37:22","extension":"xml","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":108692,"visible":true,"origin":"","legend":"","description":"","filename":"e0d88e40231647de8e1e10f356bcea351structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7501598/v1/6f73066165a60b0b9a907628.xml"},{"id":91827055,"identity":"c29ec325-e5ad-4ab5-a8c4-ed0b913c0f05","added_by":"auto","created_at":"2025-09-22 08:45:22","extension":"html","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":118421,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7501598/v1/fbe2db6ea1f7c0de33bd14f5.html"},{"id":103765444,"identity":"e9457492-77fb-48b2-b6bd-ac78e453ce2a","added_by":"auto","created_at":"2026-03-02 16:01:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":867990,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7501598/v1/39756f10-a6a1-473d-912e-000c107debe5.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Long-term Outcomes and Prognostic Factors in Surgical Endodontic Retreatment: A Retrospective Cohort Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePersistent apical periodontitis represents a significant clinical challenge in endodontics, often necessitating surgical intervention when nonsurgical endodontic retreatment is unfeasible or unsuccessful (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Endodontic microsurgery has emerged as the definitive tooth-preserving approach for such cases, particularly when anatomical complexities, persistent cysts, or extraradicular infections preclude orthograde management (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). The evolution from traditional apicoectomy to contemporary endodontic microsurgery, driven by microsurgical instruments, ultrasonic retro-tips, and high-magnification optics, has markedly improved outcomes, with modern success rates exceeding 90% (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe efficacy of endodontic microsurgery hinges critically on precise surgical technique and the biocompatibility of root-end filling materials. Calcium-enriched mixture (CEM) cement, a bioactive material with demonstrated sealing capacity and osteogenic potential, offers theoretical advantages over conventional options (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). Similar to other calcium silicate-based cements, such as mineral trioxide aggregate, it exhibits favorable biological properties. While short-term studies report favorable surgical outcomes with CEM (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e), robust long-term evidence remains scarce, limiting evidence-based clinical adoption.\u003c/p\u003e\u003cp\u003ePrognostic assessment in endodontic microsurgery is further complicated by heterogeneous methodologies across existing literature (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). Factors such as preoperative lesion size, tooth position, restorative status, and systemic health have been inconsistently examined, often within underpowered cohorts or studies lacking standardized protocols. Critically, most investigations suffer from methodological limitations: multi-operator variability, short follow-up durations prone to regression-to-mean bias, and inconsistent application of microsurgical materials/technologies (\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThis knowledge gap underscores the need for longitudinal, technique-standardized analyses. We therefore designed this 13-year retrospective cohort study with dual objectives: 1) to quantify long-term success rates of CEM-based endodontic microsurgery using composite clinical-radiographic criteria, and 2) to identify prognostic factors among demographic, tooth-related, and systemic variables, including age, smoking status, medical history, lesion characteristics, crown-root ratio, and root-end preparation depth.\u003c/p\u003e\u003cp\u003eThe null hypothesis posited that no clinical or radiographic variables would significantly influence treatment outcomes. By addressing these aims through a single-operator, STROBE-compliant design with blinded outcome assessment, this study aims to establish evidence-based benchmarks for CEM cement in surgical endodontics while refining prognostic stratification in medically complex patients.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy Design\u003c/h2\u003e\u003cp\u003eThis retrospective cohort study was conducted at Mehr Dental Clinic, Tehran, Iran. The source population included all patients who underwent surgical endodontic retreatment at the clinic between January 2011 and January 2024. The study cohort comprised patients who received surgical endodontic retreatment due to persistent apical periodontitis following either unsuccessful nonsurgical endodontic retreatment or failed initial root canal therapy.\u003c/p\u003e\u003cp\u003eThis study was approved by the Research Institute for Dental Sciences (RIDS), Shahid Beheshti University of Medical Sciences (Grant No. IR.SBMU.RIDS.43014868). Ethical clearance was obtained from the RIDS Ethics Committee (Approval No. IR.SBMU.DRC.REC.1404.046). The protocol adhered to the Declaration of Helsinki. Written informed consent was obtained from all patients for clinical treatment, while the institutional ethics committee granted a waiver of consent for retrospective review of de-identified patient records. The study design and reporting followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eData Source and Collection\u003c/h3\u003e\n\u003cp\u003eA single qualified examiner (SMH), blinded to the study\u0026rsquo;s specific hypotheses, systematically extracted preoperative, intraoperative, and postoperative clinical and radiographic data for each eligible patient/tooth encounter from the clinic\u0026rsquo;s comprehensive electronic health record system (Dental Information System; Tarasheh Hooshmand Novin, Tehran, Iran). Data extraction was conducted according to a predefined protocol to ensure accuracy and consistency across all cases.\u003c/p\u003e\n\u003ch3\u003eEligibility Criteria\u003c/h3\u003e\n\u003cp\u003eAll surgical procedures were performed by a single board-certified endodontist (SA) to minimize operator-related variability.\u003c/p\u003e\u003cp\u003e\u003cem\u003eInclusion Criteria-\u003c/em\u003e Teeth were eligible for inclusion if all of the following criteria were met:\u003c/p\u003e\u003cp\u003e\u003col\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eDiagnosis\u003c/b\u003e: Presence of persistent apical periodontitis of endodontic origin, confirmed both radiographically (e.g., Periapical Index [PAI] score\u0026thinsp;\u0026ge;\u0026thinsp;3) and clinically (e.g., presence of symptoms or sinus tract). Eligible cases included those in which: nonsurgical retreatment was deemed clinically unfeasible (e.g., presence of a post/core, complex canal anatomy precluding negotiation, separated instrument extending beyond the apex, or non-negotiable ledges), \u003cb\u003eOR\u003c/b\u003e previous nonsurgical endodontic treatment (initial therapy or retreatment) had failed, as evidenced by persistent or progressive apical periodontitis.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eData Completeness\u003c/b\u003e: Availability of comprehensive preoperative documentation, including diagnostic radiographs, clinical examination findings, and medical/dental history, as well as postoperative records comprising documented clinical assessments and at least one periapical radiograph obtained\u0026thinsp;\u0026ge;\u0026thinsp;6 months after the surgical procedure. When multiple follow-up radiographs were available, the most recent image meeting the minimum 6-month requirement was used for primary outcome assessment.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eRestorative and Periodontal Status\u003c/b\u003e: At the time of surgery, the treated tooth exhibited: an adequate and well-sealed coronal restoration (functionally intact and without clinical or radiographic evidence of marginal leakage), \u003cb\u003eAND\u003c/b\u003e periodontal health, defined as probing depths\u0026thinsp;\u0026le;\u0026thinsp;3 mm on all surfaces and absence of clinical signs of periodontitis (e.g., bleeding on probing, suppuration, or mobility greater than grade 1).\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eExclusion Criteria\u003c/em\u003e- Teeth were excluded if any of the following conditions were present:\u003c/p\u003e\u003cp\u003e\u003col\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eSurgical History\u003c/b\u003e: Prior surgical endodontic intervention on the same tooth (i.e., cases requiring re-surgery).\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eSpecific Pathologies\u003c/b\u003e: Evidence of cemental tears, root perforations (excluding iatrogenic perforations adequately managed during the index surgery), or cervical external root resorption identified either preoperatively or intraoperatively.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003ePeriodontal Disease\u003c/b\u003e: Clinical/radiographic diagnosis of chronic periodontitis affecting the involved tooth, or confirmed vertical root fracture.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eSystemic Conditions\u003c/b\u003e: Presence of uncontrolled systemic diseases known to impair healing (e.g., immunosuppressive therapy, prior head or neck radiotherapy).\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eInsufficient Data\u003c/b\u003e: Incomplete preoperative/postoperative documentation, or follow-up radiographs obtained less than 6 months after the surgical procedure.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\n\u003ch3\u003eTreatment Protocols\u003c/h3\u003e\n\u003cp\u003eAll surgical endodontic retreatments were performed by a single board-certified endodontist (SA) following a standardized microsurgical protocol under strict aseptic conditions. Written informed consent was obtained from all patients after a detailed explanation of the procedure, potential risks, benefits, and alternative treatment options. Per current clinical guidelines, all patients received preoperative medication consisting of ibuprofen 400 mg and a 0.2% chlorhexidine gluconate mouth rinse. Local anesthesia was achieved with 2% lidocaine containing 1:80,000 epinephrine (DarouPakhsh, Tehran, Iran) administered via appropriate nerve block and/or infiltration techniques.\u003c/p\u003e\u003cp\u003eAfter anesthesia, a full-thickness mucoperiosteal flap was reflected to provide optimal surgical access. A flap design (submarginal, triangular, rectangular, or papilla-base-preserving) was selected based on tooth location, access requirements, and esthetic considerations, with meticulous care to minimize papillary trauma. An osteotomy was performed to create a conservative bony window (~\u0026thinsp;3\u0026ndash;5 mm) directly over the root apex using sterile high-speed surgical burs under copious irrigation. Bone removal was minimized to preserve structural integrity. Curettage of all pathological periradicular tissues, including granulomatous and cystic lesions, was performed with sharp curettes.\u003c/p\u003e\u003cp\u003eRoot-end resection involved the removal of approximately 2\u0026ndash;3 mm of the root apex perpendicular to the long axis of the tooth, using a fine tapered fissure bur under continuous irrigation, with the bevel angle kept to a minimum. Root-end inspection under magnification ensured the identification of isthmuses, accessory canals, or missed canals. A class I root-end cavity (~\u0026thinsp;3 mm deep) was prepared at the center of the resected surface using an ultrasonic retrotip (e.g., Joya Electronic, Tehran, Iran) operated at low power under constant irrigation.\u003c/p\u003e\u003cp\u003eRoot-end filling was performed with CEM cement (BioniqueDent, Tehran, Iran), prepared according to the manufacturer\u0026rsquo;s instructions and mixed to an appropriate consistency. The cement was incrementally placed into the cavity using micro-pluggers, condensed to achieve a dense, void-free fill, and any excess material was removed. A periapical radiograph confirmed complete resection, preparation, and filling/sealing.\u003c/p\u003e\u003cp\u003eThe surgical site was thoroughly irrigated with sterile saline, and meticulous hemostasis was maintained throughout. The flap was precisely repositioned and secured with non-resorbable 4\u0026thinsp;\u0026minus;\u0026thinsp;0 silk sutures, followed by gentle digital pressure with moist gauze for at least three minutes to improve adaptation and minimize coagulum thickness.\u003c/p\u003e\u003cp\u003e Postoperative care included detailed written and verbal instructions on analgesic use, antimicrobial mouth rinse, soft diet recommendations, and oral hygiene precautions. Sutures were removed 5\u0026ndash;7 days post-surgery.\u003c/p\u003e\n\u003ch3\u003eRadiographic Assessment and Technique\u003c/h3\u003e\n\u003cp\u003eDigital periapical radiographs were obtained preoperatively, immediately postoperatively to verify root-end filling placement, and at all subsequent follow-up visits using a standardized protocol to ensure consistency and optimal diagnostic quality. Radiographs were acquired employing a strict paralleling technique with a Rinn XCP beam-guiding device (FPS 3000, Dentsply Sirona, India). All exposures were performed using a single Soredex X-ray unit (Tuusula, Finland) operating at 60 kVp and 7.5 mA. Phosphor Storage Plates (PSPs; Digora Optime, Soredex, Tuusula, Finland) of appropriate size served as image receptors. Exposure times were standardized according to tooth type and anatomical region based on initial phantom calibrations to optimize image quality while minimizing radiation dose. PSPs were processed immediately after exposure using the Digora Optime scanner (Soredex) following the manufacturer\u0026rsquo;s instructions.\u003c/p\u003e\u003cp\u003eRadiographic evaluations were conducted under strictly controlled viewing conditions. Images were displayed on a high-resolution, DICOM-calibrated 34-inch HP Envy curved monitor (resolution: 3440 \u0026times; 1440 pixels; HP, Palo Alto, CA, USA) in a dedicated, dimly lit room. All radiographic assessments were performed by a single blinded evaluator (MH), unaware of clinical data, patient identifiers, and surgical details. Before the study assessment, the examiner underwent rigorous calibration using a separate set of 50 standardized periapical radiographs not included in the study sample. Inter- and intra-examiner agreement were quantified using Cohen\u0026rsquo;s Kappa (κ) statistic, with values\u0026thinsp;\u0026ge;\u0026thinsp;0.75 indicating substantial to excellent reliability. Results of the reliability assessment are presented in the Results section.\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eData Collection\u003c/h2\u003e\u003cp\u003eAll data were extracted from electronic health records using a standardized case report form and entered into a Microsoft Excel database (Version 2016; Microsoft, Redmond, WA, USA). The following variables were systematically recorded:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003ePatient-Related Factors\u003c/b\u003e: Age (years; continuous), sex (male/female), medical history categorized by ASA classification (ASA I: healthy; ASA II: mild systemic disease; ASA III and above: uncontrolled conditions), and smoking status (never, former, or current, with pack-years quantified for current smokers).\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eTooth-Related Factors\u003c/b\u003e: Tooth type (anterior, premolar, or molar), arch location (maxillary or mandibular), root morphology (single- or multi-rooted, noting curvatures\u0026thinsp;\u0026gt;\u0026thinsp;10\u0026deg;), presence and type of intracanal post (absent or present; categorized as cast metal, prefabricated, or fiber posts), coronal restoration type (direct composite, indirect crown, or temporary), crown-root ratio (calculated as crown length to root length, categorized as \u0026le;\u0026thinsp;1 or \u0026gt;\u0026thinsp;1), and preoperative periodontal status including probing depths and mobility grade.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eTreatment-Related Factors\u003c/b\u003e: Preoperative lesion size measured in millimeters (mm) on digital radiographs using standardized software, root resection length (mm) measured intraoperatively, root-end preparation depth (mm) confirmed during surgery, and follow-up duration in months calculated from the date of surgery.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eOutcome-Related Factors\u003c/b\u003e: Clinical success or failure recorded as a binary variable, radiographic healing categorized according to both PAI and time-to-failure in months for survival analysis.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eOutcome Evaluation\u003c/h3\u003e\n\u003cp\u003e\u003cstrong\u003eSuccess\u003c/strong\u003e\u003cp\u003eTreatment was considered successful when \u003cem\u003eboth\u003c/em\u003e clinical and radiographic parameters were within normal limits. Radiographic success was defined as PAI scores of 1, or stable/slightly widened periodontal ligament space (PAI 2\u0026ndash;3) with evidence of healing and no clinical symptoms (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eFailure\u003c/strong\u003e\u003cp\u003eClinical failure was defined by the presence of persistent postoperative pain, tenderness to percussion or palpation, swelling, sinus tract formation, or irreparable tooth fracture. Radiographic failure included PAI scores of 4 or 5 (indicating apical radiolucency), or unchanged radiolucent lesions.\u003c/p\u003e\u003c/p\u003e\u003cp\u003eFor multirooted teeth, the root with the poorest radiographic prognosis determined the overall radiographic outcome of the tooth. Follow-up duration was calculated from the time of surgical intervention. In cases of failure, the end of the observation period was defined as the date when failure was first documented clinically or radiographically, whichever occurred earlier.\u003c/p\u003e\n\u003ch3\u003eSample Size calculation\u003c/h3\u003e\n\u003cp\u003eThis retrospective cohort utilized a census sampling approach encompassing all eligible cases meeting inclusion criteria treated between January 2011 and January 2024. No formal a priori sample size calculation was performed due to the exhaustive sampling design. Post hoc power analysis confirmed\u0026thinsp;\u0026gt;\u0026thinsp;85% power to detect clinically significant associations (HR\u0026thinsp;\u0026ge;\u0026thinsp;2.0) at α\u0026thinsp;=\u0026thinsp;0.05 using observed event rates.\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eDescriptive and inferential statistical methods were employed. In addition to calculating mean, standard deviation, and dispersion for quantitative variables and frequency distributions for qualitative ones, the Kaplan\u0026ndash;Meier curves and the log-rank test were used to assess the univariate effects of predictor variables. The Cox proportional hazards model was applied to evaluate the simultaneous effects of multiple independent variables on treatment success.\u003c/p\u003e\u003cp\u003eAdditionally, multiple logistic regression was utilized. For quantitative data, an intraclass correlation coefficient (ICC) of 0.75 or higher was considered acceptable, based on Rosner and Cohen's criteria. For qualitative data, a kappa value of 0.6 or higher was deemed acceptable. Statistical analyses were performed using IBM SPSS Statistics for Windows, Version 21.0 (IBM Corp., Armonk, NY, USA). A p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 197 teeth from 169 patients met the inclusion criteria for this retrospective cohort study. The mean duration of follow-up was 45.2\u0026thinsp;\u0026plusmn;\u0026thinsp;36.5 months. The Median follow-up duration was 34.0 months (IQR: 58), ranging from 6 to 144 months. The mean patient age was 47.8\u0026thinsp;\u0026plusmn;\u0026thinsp;11.8 years. The cohort included 55 males (32.5%) and 114 females (67.5%). In terms of tooth type, 82 anterior teeth (41.6%), 59 premolars (30.0%), and 56 molars (28.4%) were treated. Most treated teeth were located in the maxilla (92.4%, n\u0026thinsp;=\u0026thinsp;182), with only 15 teeth (7.6%) located in the mandible.\u003c/p\u003e\u003cp\u003eThe overall treatment success rate was 94.9% (187 out of 197 cases), with a 5.1% failure rate (10 out of 197). However, these outcomes reflect the expertise of a single surgical specialist in a tertiary referral center and should not be generalized to non-specialized clinical settings.\u003c/p\u003e\u003cp\u003e Reliability analysis showed excellent intra-observer agreement. For categorical variables related to healing status, Cohen\u0026rsquo;s Kappa was 1.00 (95% CI: 1.00\u0026ndash;1.00). For continuous variables such as lesion size, the intraclass correlation coefficient (ICC) was 0.83 (95% CI: 0.72\u0026ndash;0.90), indicating strong measurement reliability.\u003c/p\u003e\u003cp\u003eKaplan\u0026ndash;Meier survival analysis revealed cumulative success probabilities of 96.4% at 1 year (95% CI: 93.1\u0026ndash;98.2), 92.7% at 3 years (95% CI: 88.0\u0026ndash;95.6), and 87.3% at 5 years (95% CI: 80.9\u0026ndash;91.7).\u003c/p\u003e\u003cp\u003eIn the Cox proportional hazards regression model, adjusted for clinically relevant variables, only the patient's medical history demonstrated a statistically significant association with treatment failure (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eSuccess rates analyzed for potential prognostic factors\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" morerows=\"1\" nameend=\"c2\" namest=\"c1\" rowspan=\"2\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eSuccess\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003eFailure\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003ep Value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003en\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e%\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003en\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e%\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e.056\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003e\u003cb\u003eLesion size\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e.413\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003e\u003cb\u003eCCRR\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e.920\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003e\u003cb\u003eRoot-end preparation depth\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e.230\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eGender\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eMale\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e94.5%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e5.5%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e.751\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eFemale\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e107\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e93.8%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.2%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eSmoker\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eyes\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e85.7%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e14.3%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e.300\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eNo\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e181\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e95.3%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.7%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u003cb\u003eTooth type\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eAnterior\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e97.6%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e.412\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003ePremolar\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e93.2%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.8%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eMolar\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e92.9%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.1%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eJaw\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eMaxilla\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e172\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e94.5%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e5.5%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e.496\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eMandible\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e100%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"6\" rowspan=\"7\"\u003e\u003cp\u003e\u003cb\u003eTooth number\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e1\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e97.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.6%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"6\" rowspan=\"7\"\u003e\u003cp\u003e.946\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e2\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e97.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.6%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e3\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e100%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e4\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e93.8%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.3%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e5\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e39\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e92.9%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.1%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e6\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e92.7%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.3%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e7\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e100%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e\u003cb\u003ePost\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eNone\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e87\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e94.6%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e5.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e.503\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003ePre-fabrication\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e98.1%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.9%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eCasting\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e88.6%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e11.4%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eAmalgam-post\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e100%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e\u003cb\u003eRestoration\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eAmalgam\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e95.2%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.8%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e.865\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eComposite resin\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e74\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e96.1%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.9%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eCrown\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e93.5%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.5%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eBridge\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e100%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e\u003cb\u003eRestorative Surfaces\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eOne\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e93.5%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.5%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e.899\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eTwo\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e97%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eThree\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e100%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eBuild up\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e96.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.6%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eMedical history\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eASA\u003c/b\u003e I\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e147\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e97.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.6%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e.010\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eASA II and above\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e86%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e14%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e\u003cp\u003e\u003cb\u003eCCRR, clinical crown-to-root ratio\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eTooth number\u003c/b\u003e: FDI groups\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis 13-year retrospective cohort study demonstrated a remarkably high long-term success rate (94.9%) for surgical endodontic retreatment using CEM cement. This outcome exceeds historical success rates associated with conventional root-end filling materials, such as amalgam or IRM (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e), and aligns with more recent data on bioceramics, including a 91.6% four-year success rate for MTA reported by Kim et al. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). The superior performance of CEM cement is likely attributable to its unique bioactive properties. Upon hydration, CEM forms hydroxyapatite and continuously releases calcium and phosphate ions, which stimulate osteoblastic differentiation and cementogenesis (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). These mechanisms promote a biologically favorable periapical environment and contribute to consistent healing.\u003c/p\u003e\u003cp\u003eImportantly, systemic disease emerged as the sole significant predictor of treatment failure, with affected patients demonstrating a nearly six-fold increased risk compared to systemically healthy individuals (HR\u0026thinsp;=\u0026thinsp;5.87), and a failure rate of 14% versus 2.6%. This is consistent with the findings of Segura-Egea et al. (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e), who reported a higher prevalence of periapical radiolucencies in root-filled teeth among diabetic patients. The biological plausibility of this association is well established. Hyperglycemia reduces osteoblast activity through the accumulation of advanced glycation end-products (AGEs)(\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e), while chronic systemic inflammation alters matrix metalloproteinase/tissue inhibitor balance (MMP/TIMP), delaying bone remodeling (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e). Moreover, immunosuppressive states impair host bacterial clearance, especially in areas of residual microleakage. These mechanisms underscore the importance of comprehensive medical evaluation in treatment planning, particularly for medically compromised individuals undergoing endodontic surgery.\u003c/p\u003e\u003cp\u003e The exceptional treatment outcomes observed in this study likely reflect the synergistic influence of advanced microsurgical techniques, careful case selection, and the use of modern bioactive materials. All procedures were performed using ultrasonic root-end preparation, which has been shown to enhance biofilm removal and create well-adapted root-end cavities with superior sealing geometry. The consistent use of CEM cement, characterized by hydrophilic expansion and bioactive sealing capacity, further contributed to apical seal integrity and periapical tissue regeneration (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). Additionally, the inclusion criteria ensured that only structurally and periodontally favorable teeth (e.g., crown-root ratio\u0026thinsp;\u0026le;\u0026thinsp;1, intact periodontal attachment) were treated, which likely eliminated confounding anatomical risk factors.\u003c/p\u003e\u003cp\u003eInterestingly, lesion size was not significantly associated with treatment failure in this cohort, contrasting with prior findings such as those of Weissman et al., who reported poorer outcomes for large periapical lesions (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). This discrepancy may be explained by the exclusion of teeth with compromised periodontal support and poor crown-root ratios in the present study, suggesting that lesion size alone may not be a reliable predictor of failure when favorable anatomic conditions are preserved. Moreover, the 100% success rate observed in mandibular teeth, despite their known anatomical and surgical challenges, highlights the role of surgical expertise and meticulous flap design in optimizing access and healing in these complex cases.\u003c/p\u003e\u003cp\u003eIn our study, root-end preparation depth did not show a statistically significant association with treatment failure. However, this contrasts with previous literature emphasizing its importance for achieving a hermetic apical seal (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Notably, all cases in our cohort received a minimum of 3 mm root-end preparation (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e), often exceeding this threshold, in line with contemporary microsurgical protocols. This consistent application of adequate root-end preparation depth likely minimized variability and ensured optimal sealing, contributing to the overall high success rate observed.\u003c/p\u003e\u003cp\u003eSeveral methodological strengths support the reliability of these findings. All procedures were performed by a single endodontic microsurgeon with 15\u0026thinsp;+\u0026thinsp;years of dedicated microsurgical experience in a tertiary referral center, eliminating inter-operator variability and ensuring technical consistency. Radiographic healing was independently evaluated by a blinded examiner using the Periapical Index, demonstrating strong intra-observer agreement (κ\u0026thinsp;=\u0026thinsp;1.00, 95% CI: 1.00\u0026ndash;1.00). The extended mean follow-up period of 3.8 years allowed for the detection of delayed failures, enhancing outcome validity. However, the single-surgeon design, while minimizing variability, introduces expertise bias; these outcomes reflect the proficiency of a highly specialized surgeon and are not generalizable to non-specialist settings, where results may differ due to training, equipment, and case-selection factors. Future multicenter studies involving operators with varying expertise are essential to validate broader applicability. Additional limitations include the retrospective design, limiting control over confounding variables; aggregation of systemic diseases, precluding condition-specific prognostic analysis; and reliance on 2D radiography, which likely underestimated true healing by missing buccal/lingual defects and volumetric changes (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn clinical terms, these findings reaffirm the importance of thorough preoperative medical evaluation, particularly for identifying patients with systemic conditions that may impair healing and increase failure risk. Lesion size should not be considered a contraindication to surgical retreatment when periodontal integrity and structural support are adequate. Most importantly, this study reinforces the role of CEM cement as an effective bioceramic root-end filling material, supporting its continued use as a viable/efficacious option in endodontic microsurgery.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eSurgical endodontic retreatment with CEM cement demonstrated a 94.9% success rate over a mean follow-up of 45 months, reflecting favorable outcomes in a specialized microsurgical setting. Systemic health status emerged as the sole significant predictor of treatment failure, underscoring the necessity for preoperative risk stratification and individualized follow-up protocols. Neither lesion size nor other traditional prognostic factors correlated with failure within this cohort, suggesting that stringent case selection and microsurgical standards may mitigate these risks. While CEM cement showed clinical effectiveness as a root-end biomaterial in this context, these outcomes reflect expertise-specific conditions and warrant validation through multicenter studies encompassing diverse operator experience levels.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eFunding: This study was supported by the Research Institute for Dental sciences (RIDS), Shahid Beheshti University of Medical Sciences (Grant No. IR.SBMU.RIDS.43014868).\u003c/p\u003e\n\u003cp\u003eClinical trial number: Not applicable\u003c/p\u003e\n\u003cp\u003eHuman Ethics and consent to participate declaration: Ethical clearance was obtained from the RIDS Ethics Committee (Approval No. IR.SBMU.DRC.REC.1404.046). The protocol adhered to the Declaration of Helsinki. Written informed consent was obtained from all patients for clinical treatment, while the institutional ethics committee granted a waiver of consent for retrospective review of de-identified patient records.\u003c/p\u003e\n\u003cp\u003eConsent to Publish declaration: Not applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSetzer F, Harley M, Cheung J, Karabucak B. Possible causes for failure of endodontic surgery\u0026ndash;A retrospective series of 20 resurgery cases. European Endodontic Journal. 2021;6(2):235.\u003c/li\u003e\n\u003cli\u003eYoo Y-J, Kim D-W, Perinpanayagam H, Baek S-H, Zhu Q, Safavi K, et al. Prognostic factors of long-term outcomes in endodontic microsurgery: a retrospective cohort study over five years. Journal of Clinical Medicine. 2020;9(7):2210.\u003c/li\u003e\n\u003cli\u003eAlKhuwaitir S, Patel S, Bakhsh A, Rhodes JS, Ferr\u0026aacute;ndez LM, Mannocci F. Prognostic Factors Affecting the Outcome of Surgical Root Canal Treatment\u0026mdash;A Retrospective Cone-Beam Computed Tomography Cohort Study. Journal of Clinical Medicine. 2024;13(6):1692.\u003c/li\u003e\n\u003cli\u003eTaschieri S, Morandi B, Giovarruscio M, Francetti L, Russillo A, Corbella S. Microsurgical endodontic treatment of the upper molar teeth and their relationship with the maxillary sinus: a retrospective multicentric clinical study. BMC Oral Health. 2021;21(1):252.\u003c/li\u003e\n\u003cli\u003eAsgary S, Aram M, Fazlyab M. Comprehensive review of composition, properties, clinical applications, and future perspectives of calcium-enriched mixture (CEM) cement: a systematic analysis. Biomed Eng Online. 2024;23(1):96.\u003c/li\u003e\n\u003cli\u003eAsgary S, Ehsani S. Periradicular surgery of human permanent teeth with calcium-enriched mixture cement. Iran Endod J. 2013;8(3):140-4.\u003c/li\u003e\n\u003cli\u003eAsgary S, Alim Marvasti L, Kolahdouzan A. Indications and case series of intentional replantation of teeth. Iran Endod J. 2014;9(1):71-8.\u003c/li\u003e\n\u003cli\u003ePallar\u0026eacute;s-Serrano A, Glera-Suarez P, Tarazona-Alvarez B, Pe\u0026ntilde;arrocha-Diago M, Pe\u0026ntilde;arrocha-Diago M, Pe\u0026ntilde;arrocha-Oltra D. Prognostic factors after endodontic microsurgery: a retrospective study of 111 cases with 5 to 9 years of follow-up. Journal of endodontics. 2021;47(3):397-403.\u003c/li\u003e\n\u003cli\u003eYoo Y-J, Cho E-B, Perinpanayagam H, Gu Y, Zhu Q, Noblett WC, et al. Endodontic microsurgery outcomes over 10 years and associated prognostic factors: a retrospective cohort study. Journal of Endodontics. 2024;50(7):934-43.\u003c/li\u003e\n\u003cli\u003eAbou ElReash A, Hamama H, Comisi JC, Zaeneldin A, Xiaoli X. The effect of retrograde material type and surgical techniques on the success rate of surgical endodontic retreatment: systematic review of prospective randomized clinical trials. BMC Oral Health. 2021;21(1):375.\u003c/li\u003e\n\u003cli\u003evon Arx T, H\u0026auml;nni S, Jensen SS. Clinical results with two different methods of root-end preparation and filling in apical surgery: mineral trioxide aggregate and adhesive resin composite. J Endod. 2010;36(7):1122-9.\u003c/li\u003e\n\u003cli\u003eKohli MR, Berenji H, Setzer FC, Lee SM, Karabucak B. Outcome of Endodontic Surgery: A Meta-analysis of the Literature-Part 3: Comparison of Endodontic Microsurgical Techniques with 2 Different Root-end Filling Materials. J Endod. 2018;44(6):923-31.\u003c/li\u003e\n\u003cli\u003eVon Elm E, Altman DG, Egger M, Pocock SJ, G\u0026oslash;tzsche PC, Vandenbroucke JP. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. The lancet. 2007;370(9596):1453-7.\u003c/li\u003e\n\u003cli\u003e\u0026Oslash;rstavik D, Kerekes K, Eriksen HM. The periapical index: a scoring system for radiographic assessment of apical periodontitis. Dental Traumatology. 1986;2(1):20-34.\u003c/li\u003e\n\u003cli\u003eFern\u0026aacute;ndez-Y\u0026aacute;\u0026ntilde;ez S\u0026aacute;nchez A, Leco-Berrocal MI, Mart\u0026iacute;nez-Gonz\u0026aacute;lez JM. Metaanalysis of filler materials in periapical surgery. Med Oral Patol Oral Cir Bucal. 2008;13(3):E180-5.\u003c/li\u003e\n\u003cli\u003eKim S, Song M, Shin SJ, Kim E. A Randomized Controlled Study of Mineral Trioxide Aggregate and Super Ethoxybenzoic Acid as Root-end Filling Materials in Endodontic Microsurgery: Long-term Outcomes. J Endod. 2016;42(7):997-1002.\u003c/li\u003e\n\u003cli\u003eRahimi S, Mokhtari H, Shahi S, Kazemi A, Asgary S, Eghbal MJ, et al. Osseous reaction to implantation of two endodontic cements: Mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM). Med Oral Patol Oral Cir Bucal. 2012;17(5):e907-11.\u003c/li\u003e\n\u003cli\u003eSegura-Egea JJ, Mart\u0026iacute;n-Gonz\u0026aacute;lez J, Cabanillas-Balsera D, Fouad AF, Velasco-Ortega E, L\u0026oacute;pez-L\u0026oacute;pez J. Association between diabetes and the prevalence of radiolucent periapical lesions in root-filled teeth: systematic review and meta-analysis. Clin Oral Investig. 2016;20(6):1133-41.\u003c/li\u003e\n\u003cli\u003eHwang K-C, Choi JJE, Hussaini HM, Cooper PR, Friedlander LT. Effect of diabetes and hyperglycaemia on the physical and mechanical properties of dentine: a systematic review. Clinical oral investigations. 2025;29(1):55.\u003c/li\u003e\n\u003cli\u003eMao W, Zheng Y, Zhang W, Yin J, Liu Z, He P, et al. Enocyanin promotes osteogenesis and bone regeneration by inhibiting MMP9. International Journal of Molecular Medicine. 2024;55(1):9.\u003c/li\u003e\n\u003cli\u003eOmar N, Abdelraouf RM, Hamdy TM. Effect of different root canal irrigants on push-out bond strength of two novel root-end filling materials. BMC Oral Health. 2023;23(1):193.\u003c/li\u003e\n\u003cli\u003eWeissman A, Wigler R, Blau‐Venezia N, Goldberger T, Kfir A. Healing after surgical retreatment at four time points: A retrospective study. International Endodontic Journal. 2022;55(2):145-51.\u003c/li\u003e\n\u003cli\u003eRahimi S, Asgary S, Samiei M, Bahari M, Vahid Pakdel SM, Mahmoudi R. The Effect of Thickness on the Sealing Ability of CEM Cement as a Root-end Filling Material. J Dent Res Dent Clin Dent Prospects. 2015;9(1):6-10.\u003c/li\u003e\n\u003cli\u003eEskandar RF, Al-Habib MA, Barayan MA, Edrees HY. Outcomes of endodontic microsurgery using different calcium silicate\u0026ndash;based retrograde filling materials: a cohort retrospective cone-beam computed tomographic analysis. BMC Oral Health. 2023;23(1):70.\u003c/li\u003e\n\u003cli\u003eHuang X, Xu J, Hou B, Wang Y. Proximity of maxillary molar palatal roots to adjacent structures for endodontic microsurgery: a cone-beam computed tomography study. BMC Oral Health. 2025;25(1):21.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Apical periodontitis, CEM cement, Dental radiography, Endodontics, Calcium derivative, Mineral trioxide aggregate, Microsurgery","lastPublishedDoi":"10.21203/rs.3.rs-7501598/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7501598/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003ePersistent apical periodontitis following failed nonsurgical endodontic treatment presents significant clinical challenges. This study evaluated the long-term outcomes and prognostic factors associated with surgical retreatment using calcium-enriched mixture (CEM).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eIn this retrospective cohort study (STROBE-compliant), 197 teeth from 169 patients underwent surgical retreatment at a tertiary center between 2011 and 2024. Inclusion required documented persistent apical periodontitis unresponsive to prior orthograde endodontic therapy and a minimum radiographic follow-up of 6 months. A standardized microsurgical protocol was followed, including root-end resection, ultrasonic root-end preparation, and root-end filling with CEM cement by a single endodontist. Treatment outcomes were assessed using composite clinical and radiographic criteria. Kaplan\u0026ndash;Meier analysis was used to estimate survival probabilities, and Cox proportional hazards regression was applied to evaluate associations between clinical variables and treatment outcomes.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe mean follow-up duration was 45.2\u0026thinsp;\u0026plusmn;\u0026thinsp;36.5 months. The overall success rate was 94.9% (187/197 teeth). Failure-free survivals were 96.4%, 92.7%, and 87.3% at 1, 3, and 5 years, respectively. Multivariate analysis identified systemic disease as the sole significant predictor of failure (HR\u0026thinsp;=\u0026thinsp;5.87; 95% CI: 1.52\u0026ndash;22.68; p\u0026thinsp;=\u0026thinsp;0.010). Tooth-related factors (lesion size, crown-root ratio, and root-end preparation depth) and demographic variables showed no significant associations. Intra-observer agreement was excellent (κ\u0026thinsp;=\u0026thinsp;1.00; ICC\u0026thinsp;=\u0026thinsp;0.83).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eCEM cement-based surgical retreatment achieved 94.9% long-term success. Patients with systemic diseases exhibited a 5.87-fold higher failure risk, highlighting the critical role of medical status in prognostic assessment.\u003c/p\u003e","manuscriptTitle":"Long-term Outcomes and Prognostic Factors in Surgical Endodontic Retreatment: A Retrospective Cohort Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-22 08:37:17","doi":"10.21203/rs.3.rs-7501598/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-22T12:05:21+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-21T09:36:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"30672653712677594829182871629531979257","date":"2025-10-11T11:52:53+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-10T10:30:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"150380397609857939469724233886100398544","date":"2025-10-10T07:29:19+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-23T06:22:04+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"320967759246342885946928210475161063379","date":"2025-09-20T12:44:06+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-15T00:44:57+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-12T14:46:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-12T03:55:55+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-12T03:55:52+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-08-31T15:23:01+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9c488db6-ebbc-4b83-adef-13c87acc63ca","owner":[],"postedDate":"September 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-02T16:00:37+00:00","versionOfRecord":{"articleIdentity":"rs-7501598","link":"https://doi.org/10.1186/s12903-026-07945-z","journal":{"identity":"bmc-oral-health","isVorOnly":false,"title":"BMC Oral Health"},"publishedOn":"2026-02-23 15:57:04","publishedOnDateReadable":"February 23rd, 2026"},"versionCreatedAt":"2025-09-22 08:37:17","video":"","vorDoi":"10.1186/s12903-026-07945-z","vorDoiUrl":"https://doi.org/10.1186/s12903-026-07945-z","workflowStages":[]},"version":"v1","identity":"rs-7501598","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7501598","identity":"rs-7501598","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}