Preoperative and Postoperative Radiographic Quality Assesment of Root Canal Retreatments: A Retrospective Study

Preoperative and Postoperative Radiographic Quality Assesment of Root Canal Retreatments: A Retrospective 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 Preoperative and Postoperative Radiographic Quality Assesment of Root Canal Retreatments: A Retrospective Study Büşra SAÇAK, Özgür ER, Berdan AYDIN, Fatma AKKOCA, Günnur İLHAN This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7748378/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Mar, 2026 Read the published version in BMC Oral Health → Version 1 posted 11 You are reading this latest preprint version Abstract Background The aim of this study was to examine radiographic quality of root canal fillings in teeth undergoing retreatment compared with primary root canal treatment. Methods The radiographic quality of root canal fillings was retrospectively assessed in the preoperative and postoperative stages of retreatment. Seventy-six teeth were included in the study. The radiographic quality of the treatments was evaluated in terms of length, density, and taper, based on the criteria of the European Society of Endodontology (ESE). Results Across all teeth, 28.9% were classified as having acceptable root canal treatment quality in the preoperative phase, whereas 86.5% were classified as acceptable postoperatively. Moreover, when assessing acceptability for each parameter individually, as well as for all three parameters combined, the postoperative results were significantly more favourable. Conclusion Within the limitations of this retrospective study, the radiographic quality of root canal retreatments demonstrated a statistically significant improvement postoperatively compared with their preoperative state. Acceptability radiographic quality retreatment root canal filling. BACKGROUND Root canal treatment (RCT) is a fundamental component of high-quality and sustainable dental care. In the literature, the success rates of root canal treatments are reported to vary between 63% and 85% [ 1 , 2 ]. When endodontic treatment fails and a proper indication exists, it can be managed through non-surgical or surgical approaches. Currently, non-surgical retreatment procedures are commonly performed [ 3 ]. In the literature, the success rate of secondary root canal treatments appears to be between 61.6% and 69.3% [ 4 , 5 ]. In cases requiring retreatment, the causes of failure must be identified and addressed. One of the causes of failure is the technical quality of the root canal filling. Radiographic methods are typically used to evaluate the quality of root fillings. According to the European Society of Endodontology (ESE), radiographic adequacy of a root canal filling is defined by a tapered shape extending from the coronal third to the apex, no voids between the canal walls and the filling material, and a termination of the filling no more than 2 mm short of the apex [ 6 ]. Studies have reported that the proportion of root canal treatments that are considered acceptable is below 50% [ 7 , 8 ]. Assessing the failure rates and causes of periradicular diseases based on radiographic quality of root canal treatments is possible to some extent. Likewise, studies are required to assess the failure rates and causes of root canal retreatments based on radiographic quality. The aim of this study is to identify the technical failure reasons of primary root canal treatments (pRCTs) and to assess the healing progress radiographically following secondary root canal treatments (sRCTs). METHODS This study was conducted in accordance with the ethical standards of the institutional and national research committees and with the 1964 Helsinki Declaration and its amendments, and approved by Noninvasive Research Ethics Committee of Dokuz Eylül University, Faculty of Medicine (Approval Number: 8847-GOA). All data were anonymized prior to analysis to ensure patient confidentiality. Data were collected retrospectively by reviewing periapical diagnostic images, treatment radiographs, and routine clinical follow-up forms of all patients who had an indication for root canal retreatment and completed treatment at the Dokuz Eylul University Department of Endodontics, DEU Oral and Dental Health Application and Research Centre, between 01.01.2022 and 29.02.2024. In Turkey, the Social Security Institution mandates the acquisition of diagnostic and final radiographs for completed RCT procedures. In this study, these routinely obtained radiographs were used. Radiographic records without treatment forms, with incomplete RCTs, or with poor-quality radiographs were excluded. A total of 84 root canal retreatment cases were identified during the specified period; 8 of these were excluded due to missing or inadequate periapical radiographs. Radiographs were obtained using a Planmeca ProX™ (Planmeca®, Helsinki, Finland) periapical radiography unit + Periapical radiographs were taken with a phosphor plate system [VistaScan® (Dürr Dental, Bietigheim-Bissingen, Germany)] operating at 70 kVp and 8 mA, with an exposure time of 0.16 seconds. Ultimately, 76 teeth from 70 patients (27 males, 43 females; mean age approximately 38 years) were included in the study. Of these, 2 teeth were extracted before the completion of retreatment, and thus their postoperative radiographic quality could not be assessed — leaving 74 teeth for the postoperative analysis. In the mandibular anterior region, only one tooth met the inclusion criteria and, therefore, this mandibular incisor was excluded from intergroup statistical analysis but included in interarch comparison. Radiographic evaluations were performed by four investigators with a minimum of two years of experience; in cases of disagreement, a fifth investigator was consulted. The working length, density, and taper of each root canal were radiographically assessed according to the ESE criteria. Additionally, the presence or absence of separated instruments, periapical lesions, untreated canals, and the type of coronal restoration (e.g., filling, crown) were evaluated using both radiographs and clinical treatment forms to interpret the cases more clearly. Root canals that simultaneously met all three criteria of taper, density, and working length as indicated in the guideline recommended by the ESE were classified as "acceptable". Criteria recorded at the pRCT stage were defined as "preoperative", while those assessed after retreatment (sRCT) were defined as "postoperative". Teeth were evaluated based on their arch location (maxilla and mandible), or group (maxillary anterior, maxillary premolar, maxillary molar; mandibular premolar, mandibular molar). To determine the difference in radiographic quality between pRCT and sRCT and to evaluate the success of retreatment relative to tooth location, Chi-square, Fisher’s exact test, and McNemar’s test were used. Statistical analyses were performed using SPSS version 24.0 (Armonk, NY: IBM Corp., USA), and the significance level was set at p 0.05). When all teeth were evaluated, the proportion of teeth categorised as acceptable in the preoperative stage was 28.9%, while the postoperative acceptability rate was 86.5%. There was a statistically significant difference between preoperative and postoperative acceptability (p < 0.05), with postoperative root canal treatments found to be more radiographically acceptable. When all teeth were assessed in terms of working length, density, and taper preoperatively and postoperatively, all three parameters showed significant improvement in the postoperative stage (p < 0.05). Teeth with indications for retreatment were found more frequently in the maxillary arch than in the mandibular arch (p < 0.05). A significant difference was observed between maxillary and mandibular teeth in terms of preoperative working length adequacy (p < 0.05). Maxillary teeth were more adequate than mandibular teeth regarding preoperative working length. The percentages of preoperatively acceptable root canal treatments by arch were 36.7% in the maxilla and 14.8% in the mandible. Preoperative acceptability was significantly higher in maxillary teeth than in mandibular teeth (p 0.05) (Table 1 ). Table 1 Radiographic quality according to archs in preoperative/postoperative situations. ARCH WORKING LENGHT n (%) TAPER n (%) DENSITY n (%) ACCEPTABLE n (%) PRE ( n ) Adequate Inadequate Adequate Inadequate Adequate Inadequate Adequate Inadequate Maksilla (49) 27 (55,1) 22 (44,9) 33 (67,3) 16 (32,7) 21 (42,9) 28 (57,1) 18 (36,7) 31 (63,3) Mandibula (27) 4 (14,8) 23 (85,2) 14 (51,9) 13 (48,1) 6 (22,2) 21 (77,8) 4 (14,8) 23 (85,2) POST ( n ) Adequate Inadequate Adequate Inadequate Adequate Inadequate Adequate Inadequate Maksilla (49) 44 (89,8) 5 (10,2) 49 (100) 0 48 (98) 1 (2) 44 (89,8) 5 (10,2) Mandibula (25) 21 (84) 4 (16) 23 (92) 2 (8) 24 (96) 1 (4) 20 (80) 5 (20) No significant difference was observed between the maxillary and mandibular teeth in terms of postoperative working length, density, taper adequacy, presence of fractured instruments, or overall acceptability (p > 0.05). When both arches were evaluated individually, postoperative values were found to be significantly more favourable than preoperative values for working length, density, taper adequacy, and overall acceptability (p < 0.05) (Table 1 ). Among retreated teeth, there was a significant difference between tooth groups regarding preoperative working length adequacy (p < 0.05). Maxillary anterior teeth were more favourable in terms of preoperative working length adequacy compared to other groups. Regarding preoperative density adequacy, maxillary premolars were significantly more favourable than other groups (p 0.05). Postoperatively, there were no significant differences between tooth groups for working length, taper, density, or overall acceptability (p > 0.05). When working length adequacy was assessed by tooth group, the preoperative rates were 62.5% for anterior, 35.7% for premolars, and 31.25% for molars, while the postoperative rates were 87.5%, 88.9%, and 87%, respectively. When preoperative and postoperative working length adequacy was evaluated within each group, all groups except maxillary anterior teeth showed statistically significant improvement (p < 0.05) (Table 2 ). Table 2 Radiographic quality according to tooth groups in preoperative/postoperative situations. WORKING LENGHT n (%) TAPER n (%) DENSITY n (%) ACCEPTABLE n (%) Anterior ( n ) Adequate Inadequate Adequate Inadequate Adequate Inadequate Adequate Inadequate Preoperatif (16) 10 (62,5) 6 (37,5) 8 (50) 8 (50) 5 (31,25) 11 (68,75) 4 (25) 12 (75) Postoperatif (16) 14 (87,5) 2 (12,5) 15 (93,75) 1 (6,25) 16 (100%) 16 (100) 13 (81,25) 3 (18,75) Premolar ( n ) Preoperatif (28) 10 (35,7) 18 (64,3) 18 (64,3) 10 (35,7) 13 (46,4) 15 (53,6) 9 (32,1) 19 (67,9) Postoperatif (27) 24 (88,9) 3 (11,1) 27 (100) 0 27 (100) 0 24 (88,9) 3 (11,1) Molar ( n ) Preoperatif (32) 10 (31,25) 22 (68,75) 21 (65,6) 11 (34,4) 9 (28,1) 23 (71,9) 8 (25) 24 (75) Postoperatif (31) 27 (87) 4 (13) 30 (96,8) 1 (3,2) 29 (93,5) 2 (6,5) 27 (87) 4 (13) Preoperative density adequacy rates were 31.25% for anterior, 46.4% for premolars, and 28.1% for molars, while postoperative rates were 100%, 100%, and 93.5%, respectively. Postoperative values were significantly more favourable in all groups (p < 0.05) (Table 2 ). Preoperative taper adequacy rates were 50% for anterior, 64.3% for premolars, and 65.6% for molars, while postoperative rates were 93.75%, 100%, and 96.8%, respectively. In all tooth groups except maxillary anterior teeth, a significantly more tapered root canal filling was observed postoperatively (p < 0.05) (Table 2 ). Preoperative overall acceptability rates were 25% for anterior, 32.1% for premolars, and 25% for molars. Postoperative acceptability rates were 81.25%, 88.9%, and 87%, respectively. In all groups, postoperative values were significantly more favourable (p 0.05), a significantly higher rate of missed canals was detected in maxillary molars compared to other tooth groups (p < 0.05). The preoperative rate of periapical lesion presence among all teeth was 51.31%. Among teeth that were radiographically acceptable, 23.8% still presented with periapical lesions. In terms of preoperative lesion presence, mandibular teeth exhibited significantly more lesions compared to maxillary teeth, and mandibular premolars showed significantly more lesions than other tooth groups (p < 0.05). Of the teeth that underwent retreatment, 61 (80.3%) had restorations in place before retreatment; however, 13 of these lacked restorations upon presentation to the clinic. Fifteen teeth (19.7%) had prosthetic crowns, but 3 of these had no visible coronal structure at the time of examination. DISCUSSION In the literature, numerous studies have evaluated the aetiology and prognosis of both primary (pRCT) and secondary (sRCT) root canal treatments, including assessments of success rates, survival outcomes, and causes of failure [ 9 , 10 ]. While various studies have focused on the radiographic quality of pRCTs ]11,12], no previous study has specifically examined the extent to which the radiographic quality of a pRCT can be improved following sRCT. Conventional periapical radiographs are preferred in quality assessments owing to their ability to provide more detailed imaging [ 13 ]. In the present study, the extent to which the quality of retreatment cases could be improved in comparison to the initial pRCT was evaluated using periapical radiographs. Several studies in the literature report radiographic evaluations conducted by two or three experts [ 14 , 15 ]. In this study, to ensure more reliable assessments, radiographs were evaluated by four investigators from Oral Diagnosis & Radiology and Endodontics departments, and in cases of disagreement, a fifth investigator, an experienced endodontist, was consulted. Evaluating the radiographic quality of sRCT is considered more challenging than that of pRCT. Retreated root canal fillings are expected to meet the same technical standards required for pRCT. However, there is currently no specific method proposed for evaluating the radiographic quality of sRCT. In this study, criteria used in the evaluation of pRCT complied with the guidelines published by the European Society of Endodontology (ESE) [ 6 ]. In addition to the evaluation criteria used, remaining root canal filling material prior to obturation in sRCTs is also important. Due to the retrospective design of the study and the insufficient number of interim radiographs, this criterion could not be assessed. The use of the paralleling cone technique could have provided more consistent and reliable results, particularly in the comparison of working length and other radiographic criteria between preoperative and postoperative images. However, due to the retrospective nature of the study, this method could not be implemented and should be considered a limitation of the study. In a previous study evaluating the radiographic acceptability of pRCTs was found to be 29.6% [ 16 ]. These findings are consistent with the 28.9% preoperative acceptability rate reported in the present study. Postoperatively, the rate of acceptable sRCTs showed a clear improvement, reaching 86.5%. This increase may be attributed to the fact that all retreatments in this study were performed by endodontic specialists or postgraduate students who employed a more experienced and meticulous approach in determining working length, taper, and density. According to the literature, the most common reasons for the failure of RCTs are related to the inability to achieve adequacy in these parameters [ 17 ]. In a previous study, radiographic homogeneity of pRCTs was found to be 48.9% and working length adequacy in 77.6% of cases [ 18 ]. In the present study, the radiographic homogeneity was observed to be 35.5% preoperatively and 97.3% postoperatively, and working length was 40.8% for preoperative cases and 87.8% for postoperative counterparts. No significant difference was found between the maxilla and mandible in terms of acceptable root canal treatments in pRCTs, with rates of 56% and 58%, respectively [ 19 ]. However, in the present study, when teeth with failed pRCT are considered, maxillary teeth showed significantly higher preoperative acceptability (36.7%) compared to mandibular teeth (14.8%). These findings suggest that even though RCTs that are considered acceptable radiographically may require retreatment for other reasons, causing maxillary teeth to undergo retreatment more frequently than mandibular teeth. Although teeth in both arches appear acceptable postoperatively (maxilla: 89.8%, mandible: 80%), improvement was observed across all tooth groups. Maxillary teeth demonstrated significantly better preoperative working length adequacy compared to mandibular teeth. Although no significant difference was observed postoperatively between arches, a higher proportion of maxillary teeth were considered adequate in terms of root filling quality. This difference was attributed to a relatively greater incidence of curved and narrow root canals in mandibular molars, which may reduce the accuracy of electronic apex locators [ 20 ]. Additionally, the proximity of canals and anatomical superimpositions in mandibular molars may present challenges in access and visibility for the clinician. In a study, the cases with primary root canal fillings of acceptable quality by group were 34.2% for anterior, 23.8% for premolars, and 16.2% for molars [ 21 ]. Similarly, in the present study, the preoperative acceptability rates were 25%, 32.1%, and 25%, respectively. Postoperatively, these rates increased to 81.25%, 88.9%, and 87%. This improvement may be attributed to better working length control and higher density of fillings in all tooth groups. In this study, working length adequacy significantly improved in all groups except maxillary anterior teeth, increasing from 62.5%, 35.7%, and 31.25% (preoperatively) to 87.5%, 88.9%, and 87% (postoperatively) in the anterior, premolar, and molar groups, respectively. In another study, adequacy rates for working length were reported to be 55.9%, 44.4%, and 27.9%, respectively [ 22 ]. These findings indicate that molars tend to have root canal fillings that do not fit the quality standards emphasised by the ESE criteria, likely due to their complex anatomy. When the taper of primary root canal fillings was evaluated in our study, it was 50% for anterior, 64.3% for premolars, and 65.6% for molars, increasing to 93.75%, 100%, and 96.8% postoperatively. Adequacy in density rates preoperatively were 31.25%, 46.4%, and 28.1%, increasing to 100%, 100%, and 93.5% postoperatively. A study evaluating root canal treatments performed by dental students found that mandibular molars had the most acceptable taper and density values [ 23 ]; however, in another study conducted more recently, adequacy in taper was found to be 80%, 78%, and 44%, and in density was 75%, 70%, and 40% for anterior, premolar, and molar teeth, respectively [ 24 ]. Greater quality that meets the ESE standards was detected postoperatively in the present study owing to the retreatments being performed by experienced clinicians, suggesting that treatment outcomes may improve when performed by specialists. However, further research is required to support this observation. Preoperatively, missed canals were most commonly observed in maxillary molars (58.3%), which is consistent with the literature 40.1 % [ 25 ]; 71.8 % [ 26 ]. Among these teeth with missed canals, periapical lesions were present in 50% of cases in the present study. Missed canals are known to negatively affect periapical tissues and increase the prevalence of lesion development. In this study, 51.31% of the teeth requiring retreatment showed preoperative periapical lesions. Previous studies reported the prevalence of apical periodontitis in root-filled teeth ranging from 31.7% to 72.1% [ 27 , 28 ]. In our study, mandibular premolars showed the highest rate of preoperative periapical lesions; likewise, the literature has more commonly reported molars [ 22 ], likely due to the greater technical difficulty associated with their complex anatomy. Because the number of follow-up cases was insufficient, no postoperative periapical status could be reported for sRCTs in the present study. Among the cases with pRCTs that fit the ESE criteria in terms of radiographic root canal filling quality, periapical lesions were still detected in 23.8% of the cases. According to the literature, this rate ranges between 10.2% and 25.2% [ 27 , 29 ]. These findings suggest that high technical quality alone does not guarantee treatment success, which must be consolidated by managing canal anatomy complexity, disinfection, longevity and sealing of the coronal restoration, and other required clinical parameters that significantly influence treatment outcomes. CONCLUSION Within the limitations of this retrospective study, it was observed that root canal retreatment procedures led to a statistically significant improvement in the radiographic quality of root canal fillings compared to the preoperative condition. However, the fact that ideal technical standards were not achieved in all cases reveals the challenges and technical sensitivity required for retreatment procedures. The findings of this study highlight the critical importance of accurately determining the working length, followed by sufficient cleaning and shaping, and providing a three-dimensional root canal filling in retreatment cases. Additionally, factors such as undetected missed canals in primary root canal treatments and the presence of residual filling material during retreatment must be carefully considered for their impact on postoperative success. Although the findings suggest that performing root canal retreatments by experienced clinicians may improve radiographic quality, this must be further supported by prospective studies that include clinical examination and follow-up. Abbreviations ESE European Society of Endodontology RCT Root Canal Treatment pRCT Primary Root Canal Treatment sRCT Secondary Root Canal Treatment Declarations This study was approved by the Noninvasive Research Ethics Committee of Dokuz Eylül University, Faculty of Medicine (8847-GOA). Ethics approval and consent to participate Institutional consent was obtained from all patients treated at Dokuz Eylul University Department of Endodontics, DEU Oral and Dental Health Application and Research Centre (Noninvasive Research Ethics Committee of Dokuz Eylül University, Faculty of Medicine (8847-GOA)). Data were anonymized prior to analysis to ensure the protection of patient confidentiality. Consent for publication A written informed consent for publication was obtained from all patients treated at Dokuz Eylul University, Department of Endodontics, DEU Oral and Dental Health Application and Research Centre. Availability of data and materials The datasets used and/or analyzed during the current study are available in the institutional archive of Dokuz Eylul University, Department of Endodontics. Data can be obtained from the corresponding author upon reasonable request. Competing Interests We declare that the authors have no competing interests as defined by BMC, or other interests that might be perceived to influence the results and/or discussion reported in this paper. Funding The authors declare that this work was not supported or funded by any organization, agency, or institution. Authors' contributions B.S. has written the entire manuscript, performed the data collection, O.E. set the hypothesis, performed data collection and literature review. B.A. performed data collection and evaluation, and proof reading. F.A. performed data collection and evaluation, proof reading, and statistics. G.I. performed data collection and evaluation. Acknowledgements The authors declare no acknowledgements to be made for present study. References Patel S, Wilson R, Dawood A, Foschi F, Mannocci F. The detection of periapical pathosis using digital periapical radiography and cone beam computed tomography – part 2: a 1-year post-treatment follow-up. Int Endod J. 2012;45(8):711–23. Ng YL, Mann V, Rahbaran S, Lewsey J, Gulabivala K. Outcome of primary root canal treatment: systematic review of the literature – part 1. Effects of study characteristics on probability of success. Int Endod J. 2007;40(12):921–39. Ruddle CJ. Nonsurgical endodontic retreatment. J Calif Dent Assoc. 1997;25(11):769–96. Gorni FG, Gagliani MM. The outcome of endodontic retreatment: a 2-yr follow-up. J Endod. 2004;30(1):1–4. Çalışkan MK. Nonsurgical retreatment of teeth with periapical lesions previously managed by either endodontic or surgical intervention. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005;100(2):242–8. Wesselink PR. Consensus report of the European Society of Endodontology on quality guidelines for endodontic treatment. Int Endod J. 1994;27(3). Laukkanen E, Vehkalahti MM, Kotiranta AK. Radiographic outcome of root canal treatment in general dental practice: tooth type and quality of root filling as prognostic factors. Acta Odontol Scand. 2021;79(1):37–42. Boucher Y, Matossian L, Rilliard F, Machtou P. Radiographic evaluation of the prevalence and technical quality of root canal treatment in a French subpopulation. Int Endod J. 2002;35(3):229–38. Ng YL, Mann V, Gulabivala K. A prospective study of the factors affecting outcomes of non-surgical root canal treatment: part 1: periapical health. Int Endod J. 2011;44(7):583–609. Siqueira JF Jr. Aetiology of root canal treatment failure: why well-treated teeth can fail. Int Endod J. 2001;34(1):1–10. Ribeiro DM, Réus JC, Felippe WT, Pachêco-Pereira C, Dutra KL, Santos JN, et al. Technical quality of root canal treatment performed by undergraduate students using hand instrumentation: a meta-analysis. Int Endod J. 2018;51(3):269–83. Colombo M, Bassi C, Beltrami R, Vigorelli P, Spinelli A, Cavada A, et al. Radiographic technical quality of root canal treatment performed by a new rotary single-file system. Ann Stomatol. 2017;8(1):18. Patel S, Brown J, Semper M, Abella F, Mannocci F. European Society of Endodontology position statement: Use of CBCT in endodontics. Int Endod J. 2019;52(12):1675–77. Vukadinov T, Blažić L, Kantardžić I, Lainović T. Technical quality of root fillings performed by undergraduate students: a radiographic study. ScientificWorldJournal. 2014;2014:751274. Bierenkrant DE, Parashos P, Messer HH. The technical quality of nonsurgical root canal treatment performed by a selected cohort of Australian endodontists. Int Endod J. 2008;41(7):561–70. El Merini H, Amarir H, Lamzawaq A, Hamza M. Periapical status and quality of root canal fillings in a Moroccan subpopulation. Int J Dent. 2017;2017:1068982. Dugas NN, Lawrence HP, Teplitsky PE, Pharoah MJ, Friedman S. Periapical health and treatment quality assessment of root-filled teeth in two Canadian populations. Int Endod J. 2003;36(3):181–92. Lee AHC, Cheung GSP, Wong MCM. Long-term outcome of primary non-surgical root canal treatment. Clin Oral Investig. 2012;16:1607–17. Laukkanen E, Vehkalahti MM, Kotiranta AK. Radiographic outcome of root canal treatment in general dental practice: tooth type and quality of root filling as prognostic factors. Acta Odontol Scand. 2021;79(1):37–42. Shabahang S, Goon WW, Gluskin AH. An in vivo evaluation of Root ZX electronic apex locator. J Endod. 1996;22(11):616–18. Boucher Y, Matossian L, Rilliard F, Machtou P. Radiographic evaluation of the prevalence and technical quality of root canal treatment in a French subpopulation. Int Endod J. 2002;35(3):229–38. Meirinhos J, Martins JNR, Pereira B, Baruwa A, Gouveia J, Quaresma SA, et al. Prevalence of apical periodontitis and its association with previous root canal treatment, root canal filling length and type of coronal restoration – a cross-sectional study. Int Endod J. 2020;53(4):573–84. Habib AA, et al. Radiographic assessment of the quality of root canal fillings performed by senior dental students. Eur Endod J. 2018;3(2):101–6. Barış SD, Hançerlioğulları D, Şahbaz BS, Erdemir A. Lisans öğrencileri tarafından yapılan kök kanal tedavilerinin kalitesinin radyografik olarak değerlendirilmesi. J Kırıkkale Univ Fac Med. 2021;26(2):120–8. Karabucak B, Bunes A, Chehoud C, Kohli MR, Setzer F. Prevalence of apical periodontitis in endodontically treated premolars and molars with untreated canal: a cone-beam computed tomography study. J Endod. 2016;42(4):538–41. Rouhani A, Aboutorabzadeh SM, Reyhani M, Kheirabadi N, Mortazavi S, Navabi S. Prevalence of missed canals in endodontically treated teeth: a cone-beam computed tomography study. J Clin Exp Dent. 2023;15(8):e605. Hussain MA, Singh SK, Naz S, Haque M, Shah HK, Singh A. Predictors of apical periodontitis in root canal treated teeth from an adult Nepalese subpopulation: a cross-sectional study. BMC Oral Health. 2024;24(1):400. El Ouarti I, Chala S, Sakout M, Abdallaoui F. Prevalence and risk factors of apical periodontitis in endodontically treated teeth: cross-sectional study in an adult Moroccan subpopulation. BMC Oral Health. 2021;21:1–10. De Moor RJG, Hommez GMG, De Boever JG, Delme KIM, Martens GEI. Periapical health related to the quality of root canal treatment in a Belgian population. Int Endod J. 2000;33(2):113–20. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 10 Mar, 2026 Read the published version in BMC Oral Health → Version 1 posted Editorial decision: Revision requested 25 Dec, 2025 Reviews received at journal 23 Dec, 2025 Reviewers agreed at journal 20 Dec, 2025 Reviews received at journal 14 Nov, 2025 Reviewers agreed at journal 23 Oct, 2025 Reviewers agreed at journal 23 Oct, 2025 Reviewers invited by journal 21 Oct, 2025 Editor assigned by journal 21 Oct, 2025 Editor invited by journal 21 Oct, 2025 Submission checks completed at journal 20 Oct, 2025 First submitted to journal 20 Oct, 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7748378","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":534161237,"identity":"f49431af-20c6-4c13-a63b-89cf1ea8c531","order_by":0,"name":"Büşra SAÇAK","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7klEQVRIie3RsQqCQBjA8U8OdPkewKHoFQ6EShB7FSXQxSZBGg8CJ6G1HqOl2ThobHYKQmhycHQISsOihtPGhvsvdxz8uO84AJnsD6PtihoDSEv167CH4BHgsHkTp59AQwj+Qia6fy0rsAc4Wl24FVku01Z7XanOQmJuAmObwBxRVSkPTp7L8Bjp4ITiwbKAAEKKMxWBL2LuMj0Y10Q8Gc38XLnVBBtixneXjYo+4hgEX0SJ0/oW7CZmUhhkQJu3ePSQnOZGjF44dTwxmWj1YMXSniHheVlF9nCt8V1WWmLSjvexf35NH5DJZDJZdw8WJkjQxt81BgAAAABJRU5ErkJggg==","orcid":"","institution":"Dokuz Eylül University","correspondingAuthor":true,"prefix":"","firstName":"Büşra","middleName":"","lastName":"SAÇAK","suffix":""},{"id":534161238,"identity":"afc1841d-fc89-4fc5-9e41-2387de5f4d9c","order_by":1,"name":"Özgür ER","email":"","orcid":"","institution":"Dokuz Eylül University","correspondingAuthor":false,"prefix":"","firstName":"Özgür","middleName":"","lastName":"ER","suffix":""},{"id":534161239,"identity":"dcccbc0d-f044-45db-853e-3d39b2cb9ce0","order_by":2,"name":"Berdan AYDIN","email":"","orcid":"","institution":"Dokuz Eylül University","correspondingAuthor":false,"prefix":"","firstName":"Berdan","middleName":"","lastName":"AYDIN","suffix":""},{"id":534161240,"identity":"55f554a4-2534-4f7b-a64d-a448dd806655","order_by":3,"name":"Fatma AKKOCA","email":"","orcid":"","institution":"Dokuz Eylül University","correspondingAuthor":false,"prefix":"","firstName":"Fatma","middleName":"","lastName":"AKKOCA","suffix":""},{"id":534161241,"identity":"e2d83806-47fc-4a5b-8aaf-8b63cc6e9d93","order_by":4,"name":"Günnur İLHAN","email":"","orcid":"","institution":"Dokuz Eylül University","correspondingAuthor":false,"prefix":"","firstName":"Günnur","middleName":"","lastName":"İLHAN","suffix":""}],"badges":[],"createdAt":"2025-09-30 07:23:31","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7748378/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7748378/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12903-026-08051-w","type":"published","date":"2026-03-10T16:00:19+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":94986095,"identity":"983f9b7f-8b3e-48cd-9224-9145a048c0b0","added_by":"auto","created_at":"2025-11-03 06:59:47","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":32283,"visible":true,"origin":"","legend":"","description":"","filename":"BMCORALHEALTHSUBMISSION20OCT2025.docx","url":"https://assets-eu.researchsquare.com/files/rs-7748378/v1/83050482bfa7bc9d5d0e06a0.docx"},{"id":94874037,"identity":"4e8c7ccf-36b2-4aaf-a5fc-8b62c0e9b1d4","added_by":"auto","created_at":"2025-10-31 15:26:27","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":6379,"visible":true,"origin":"","legend":"","description":"","filename":"a341741b342c4f74901f6df34edc2214.json","url":"https://assets-eu.researchsquare.com/files/rs-7748378/v1/4380e54747e033e94df18ea6.json"},{"id":94874039,"identity":"ab8dd5d3-0698-453f-9cf0-aa5607a3a3c1","added_by":"auto","created_at":"2025-10-31 15:26:27","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":87573,"visible":true,"origin":"","legend":"","description":"","filename":"a341741b342c4f74901f6df34edc22141enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7748378/v1/ac866721f906347431e5efa9.xml"},{"id":94874040,"identity":"0599bd3d-c39d-4937-a846-c3c097b7f50a","added_by":"auto","created_at":"2025-10-31 15:26:27","extension":"xml","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":84460,"visible":true,"origin":"","legend":"","description":"","filename":"a341741b342c4f74901f6df34edc22141structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7748378/v1/4de07f2653f5bca3cd00a075.xml"},{"id":94985579,"identity":"22e388d5-73f3-4fb2-b4f7-0c2ba77362db","added_by":"auto","created_at":"2025-11-03 06:58:27","extension":"html","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":93862,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7748378/v1/697030793f3eb77176fb501b.html"},{"id":104739639,"identity":"207d7ddd-74f7-4c8d-b5ec-fc76993836a3","added_by":"auto","created_at":"2026-03-16 16:11:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":651969,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7748378/v1/19b202ab-de72-48eb-b419-5a8a1201e7b0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003ePreoperative and Postoperative Radiographic Quality Assesment of Root Canal Retreatments: A Retrospective Study\u003c/p\u003e","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eRoot canal treatment (RCT) is a fundamental component of high-quality and sustainable dental care. In the literature, the success rates of root canal treatments are reported to vary between 63% and 85% [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eWhen endodontic treatment fails and a proper indication exists, it can be managed through non-surgical or surgical approaches. Currently, non-surgical retreatment procedures are commonly performed [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. In the literature, the success rate of secondary root canal treatments appears to be between 61.6% and 69.3% [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In cases requiring retreatment, the causes of failure must be identified and addressed. One of the causes of failure is the technical quality of the root canal filling. Radiographic methods are typically used to evaluate the quality of root fillings. According to the European Society of Endodontology (ESE), radiographic adequacy of a root canal filling is defined by a tapered shape extending from the coronal third to the apex, no voids between the canal walls and the filling material, and a termination of the filling no more than 2 mm short of the apex [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Studies have reported that the proportion of root canal treatments that are considered acceptable is below 50% [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAssessing the failure rates and causes of periradicular diseases based on radiographic quality of root canal treatments is possible to some extent. Likewise, studies are required to assess the failure rates and causes of root canal retreatments based on radiographic quality.\u003c/p\u003e\u003cp\u003eThe aim of this study is to identify the technical failure reasons of primary root canal treatments (pRCTs) and to assess the healing progress radiographically following secondary root canal treatments (sRCTs).\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003e This study was conducted in accordance with the ethical standards of the institutional and national research committees and with the 1964 Helsinki Declaration and its amendments, and approved by Noninvasive Research Ethics Committee of Dokuz Eyl\u0026uuml;l University, Faculty of Medicine (Approval Number: 8847-GOA). All data were anonymized prior to analysis to ensure patient confidentiality. Data were collected retrospectively by reviewing periapical diagnostic images, treatment radiographs, and routine clinical follow-up forms of all patients who had an indication for root canal retreatment and completed treatment at the Dokuz Eylul University Department of Endodontics, DEU Oral and Dental Health Application and Research Centre, between 01.01.2022 and 29.02.2024.\u003c/p\u003e\u003cp\u003eIn Turkey, the Social Security Institution mandates the acquisition of diagnostic and final radiographs for completed RCT procedures. In this study, these routinely obtained radiographs were used. Radiographic records without treatment forms, with incomplete RCTs, or with poor-quality radiographs were excluded. A total of 84 root canal retreatment cases were identified during the specified period; 8 of these were excluded due to missing or inadequate periapical radiographs.\u003c/p\u003e\u003cp\u003eRadiographs were obtained using a Planmeca ProX\u0026trade; (Planmeca\u0026reg;, Helsinki, Finland) periapical radiography unit\u0026thinsp;+\u0026thinsp;Periapical radiographs were taken with a phosphor plate system [VistaScan\u0026reg; (D\u0026uuml;rr Dental, Bietigheim-Bissingen, Germany)] operating at 70 kVp and 8 mA, with an exposure time of 0.16 seconds. Ultimately, 76 teeth from 70 patients (27 males, 43 females; mean age approximately 38 years) were included in the study. Of these, 2 teeth were extracted before the completion of retreatment, and thus their postoperative radiographic quality could not be assessed \u0026mdash; leaving 74 teeth for the postoperative analysis. In the mandibular anterior region, only one tooth met the inclusion criteria and, therefore, this mandibular incisor was excluded from intergroup statistical analysis but included in interarch comparison.\u003c/p\u003e\u003cp\u003eRadiographic evaluations were performed by four investigators with a minimum of two years of experience; in cases of disagreement, a fifth investigator was consulted. The working length, density, and taper of each root canal were radiographically assessed according to the ESE criteria. Additionally, the presence or absence of separated instruments, periapical lesions, untreated canals, and the type of coronal restoration (e.g., filling, crown) were evaluated using both radiographs and clinical treatment forms to interpret the cases more clearly.\u003c/p\u003e\u003cp\u003e Root canals that simultaneously met all three criteria of taper, density, and working length as indicated in the guideline recommended by the ESE were classified as \"acceptable\". Criteria recorded at the pRCT stage were defined as \"preoperative\", while those assessed after retreatment (sRCT) were defined as \"postoperative\".\u003c/p\u003e\u003cp\u003eTeeth were evaluated based on their arch location (maxilla and mandible), or group (maxillary anterior, maxillary premolar, maxillary molar; mandibular premolar, mandibular molar). To determine the difference in radiographic quality between pRCT and sRCT and to evaluate the success of retreatment relative to tooth location, Chi-square, Fisher\u0026rsquo;s exact test, and McNemar\u0026rsquo;s test were used. Statistical analyses were performed using SPSS version 24.0 (Armonk, NY: IBM Corp., USA), and the significance level was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eAmong the 76 teeth that underwent root canal retreatment, no statistically significant difference was found between the arches or tooth groups in terms of gender (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). When all teeth were evaluated, the proportion of teeth categorised as acceptable in the preoperative stage was 28.9%, while the postoperative acceptability rate was 86.5%. There was a statistically significant difference between preoperative and postoperative acceptability (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), with postoperative root canal treatments found to be more radiographically acceptable. When all teeth were assessed in terms of working length, density, and taper preoperatively and postoperatively, all three parameters showed significant improvement in the postoperative stage (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003cp\u003eTeeth with indications for retreatment were found more frequently in the maxillary arch than in the mandibular arch (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003cp\u003eA significant difference was observed between maxillary and mandibular teeth in terms of preoperative working length adequacy (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Maxillary teeth were more adequate than mandibular teeth regarding preoperative working length. The percentages of preoperatively acceptable root canal treatments by arch were 36.7% in the maxilla and 14.8% in the mandible. Preoperative acceptability was significantly higher in maxillary teeth than in mandibular teeth (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). No significant difference was found between the arches regarding other preoperative criteria (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (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\u003eRadiographic quality according to archs in preoperative/postoperative situations.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eARCH\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eWORKING LENGHT \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eTAPER \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003eDENSITY \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e\u003cp\u003eACCEPTABLE \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePRE (\u003cem\u003en\u003c/em\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAdequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInadequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAdequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInadequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAdequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInadequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eAdequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eInadequate\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMaksilla (49)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e27 (55,1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22 (44,9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e33 (67,3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e16 (32,7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e21 (42,9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e28 (57,1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e18 (36,7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e31 (63,3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMandibula (27)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4 (14,8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e23 (85,2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e14 (51,9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13 (48,1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6 (22,2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e21 (77,8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e4 (14,8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e23 (85,2)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePOST (\u003c/b\u003e\u003cb\u003en\u003c/b\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eAdequate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eInadequate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003eAdequate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003eInadequate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003eAdequate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u003cb\u003eInadequate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u003cb\u003eAdequate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e\u003cb\u003eInadequate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMaksilla (49)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e44 (89,8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5 (10,2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e49 (100)\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\u003e48 (98)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1 (2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e44 (89,8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e5 (10,2)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMandibula (25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21 (84)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (16)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e23 (92)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2 (8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e24 (96)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1 (4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e20 (80)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e5 (20)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eNo significant difference was observed between the maxillary and mandibular teeth in terms of postoperative working length, density, taper adequacy, presence of fractured instruments, or overall acceptability (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). When both arches were evaluated individually, postoperative values were found to be significantly more favourable than preoperative values for working length, density, taper adequacy, and overall acceptability (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAmong retreated teeth, there was a significant difference between tooth groups regarding preoperative working length adequacy (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Maxillary anterior teeth were more favourable in terms of preoperative working length adequacy compared to other groups. Regarding preoperative density adequacy, maxillary premolars were significantly more favourable than other groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). No significant differences were observed between tooth groups in terms of preoperative taper adequacy or preoperative acceptability (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Postoperatively, there were no significant differences between tooth groups for working length, taper, density, or overall acceptability (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\u003cp\u003eWhen working length adequacy was assessed by tooth group, the preoperative rates were 62.5% for anterior, 35.7% for premolars, and 31.25% for molars, while the postoperative rates were 87.5%, 88.9%, and 87%, respectively. When preoperative and postoperative working length adequacy was evaluated within each group, all groups except maxillary anterior teeth showed statistically significant improvement (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eRadiographic quality according to tooth groups in preoperative/postoperative situations.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eWORKING LENGHT \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eTAPER \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003eDENSITY \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e\u003cp\u003eACCEPTABLE \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnterior (\u003cem\u003en\u003c/em\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAdequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInadequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAdequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInadequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAdequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInadequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eAdequate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eInadequate\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePreoperatif (16)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (62,5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6 (37,5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e8 (50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8 (50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e5 (31,25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e11 (68,75)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e4 (25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e12 (75)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePostoperatif (16)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14 (87,5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (12,5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15 (93,75)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (6,25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e16 (100%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e16 (100)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e13 (81,25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e3 (18,75)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePremolar (\u003c/b\u003e\u003cb\u003en\u003c/b\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePreoperatif (28)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (35,7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18 (64,3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e18 (64,3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10 (35,7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e13 (46,4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e15 (53,6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e9 (32,1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e19 (67,9)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePostoperatif (27)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e24 (88,9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (11,1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e27 (100)\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\u003e27 (100)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e24 (88,9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e3 (11,1)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMolar (\u003c/b\u003e\u003cb\u003en\u003c/b\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePreoperatif (32)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (31,25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22 (68,75)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e21 (65,6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e11 (34,4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9 (28,1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e23 (71,9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e8 (25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e24 (75)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePostoperatif (31)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e27 (87)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (13)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e30 (96,8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (3,2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e29 (93,5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2 (6,5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e27 (87)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e4 (13)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePreoperative density adequacy rates were 31.25% for anterior, 46.4% for premolars, and 28.1% for molars, while postoperative rates were 100%, 100%, and 93.5%, respectively. Postoperative values were significantly more favourable in all groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003ePreoperative taper adequacy rates were 50% for anterior, 64.3% for premolars, and 65.6% for molars, while postoperative rates were 93.75%, 100%, and 96.8%, respectively. In all tooth groups except maxillary anterior teeth, a significantly more tapered root canal filling was observed postoperatively (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003ePreoperative overall acceptability rates were 25% for anterior, 32.1% for premolars, and 25% for molars. Postoperative acceptability rates were 81.25%, 88.9%, and 87%, respectively. In all groups, postoperative values were significantly more favourable (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAlthough there was no significant difference between the arches in terms of missed canals preoperatively (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05), a significantly higher rate of missed canals was detected in maxillary molars compared to other tooth groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003cp\u003eThe preoperative rate of periapical lesion presence among all teeth was 51.31%. Among teeth that were radiographically acceptable, 23.8% still presented with periapical lesions. In terms of preoperative lesion presence, mandibular teeth exhibited significantly more lesions compared to maxillary teeth, and mandibular premolars showed significantly more lesions than other tooth groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003cp\u003eOf the teeth that underwent retreatment, 61 (80.3%) had restorations in place before retreatment; however, 13 of these lacked restorations upon presentation to the clinic. Fifteen teeth (19.7%) had prosthetic crowns, but 3 of these had no visible coronal structure at the time of examination.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eIn the literature, numerous studies have evaluated the aetiology and prognosis of both primary (pRCT) and secondary (sRCT) root canal treatments, including assessments of success rates, survival outcomes, and causes of failure [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. While various studies have focused on the radiographic quality of pRCTs ]11,12], no previous study has specifically examined the extent to which the radiographic quality of a pRCT can be improved following sRCT.\u003c/p\u003e\u003cp\u003eConventional periapical radiographs are preferred in quality assessments owing to their ability to provide more detailed imaging [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In the present study, the extent to which the quality of retreatment cases could be improved in comparison to the initial pRCT was evaluated using periapical radiographs.\u003c/p\u003e\u003cp\u003eSeveral studies in the literature report radiographic evaluations conducted by two or three experts [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In this study, to ensure more reliable assessments, radiographs were evaluated by four investigators from Oral Diagnosis \u0026amp; Radiology and Endodontics departments, and in cases of disagreement, a fifth investigator, an experienced endodontist, was consulted. Evaluating the radiographic quality of sRCT is considered more challenging than that of pRCT. Retreated root canal fillings are expected to meet the same technical standards required for pRCT. However, there is currently no specific method proposed for evaluating the radiographic quality of sRCT. In this study, criteria used in the evaluation of pRCT complied with the guidelines published by the European Society of Endodontology (ESE) [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn addition to the evaluation criteria used, remaining root canal filling material prior to obturation in sRCTs is also important. Due to the retrospective design of the study and the insufficient number of interim radiographs, this criterion could not be assessed.\u003c/p\u003e\u003cp\u003eThe use of the paralleling cone technique could have provided more consistent and reliable results, particularly in the comparison of working length and other radiographic criteria between preoperative and postoperative images. However, due to the retrospective nature of the study, this method could not be implemented and should be considered a limitation of the study.\u003c/p\u003e\u003cp\u003eIn a previous study evaluating the radiographic acceptability of pRCTs was found to be 29.6% [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. These findings are consistent with the 28.9% preoperative acceptability rate reported in the present study. Postoperatively, the rate of acceptable sRCTs showed a clear improvement, reaching 86.5%. This increase may be attributed to the fact that all retreatments in this study were performed by endodontic specialists or postgraduate students who employed a more experienced and meticulous approach in determining working length, taper, and density. According to the literature, the most common reasons for the failure of RCTs are related to the inability to achieve adequacy in these parameters [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn a previous study, radiographic homogeneity of pRCTs was found to be 48.9% and working length adequacy in 77.6% of cases [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In the present study, the radiographic homogeneity was observed to be 35.5% preoperatively and 97.3% postoperatively, and working length was 40.8% for preoperative cases and 87.8% for postoperative counterparts.\u003c/p\u003e\u003cp\u003eNo significant difference was found between the maxilla and mandible in terms of acceptable root canal treatments in pRCTs, with rates of 56% and 58%, respectively [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. However, in the present study, when teeth with failed pRCT are considered, maxillary teeth showed significantly higher preoperative acceptability (36.7%) compared to mandibular teeth (14.8%). These findings suggest that even though RCTs that are considered acceptable radiographically may require retreatment for other reasons, causing maxillary teeth to undergo retreatment more frequently than mandibular teeth.\u003c/p\u003e\u003cp\u003eAlthough teeth in both arches appear acceptable postoperatively (maxilla: 89.8%, mandible: 80%), improvement was observed across all tooth groups.\u003c/p\u003e\u003cp\u003eMaxillary teeth demonstrated significantly better preoperative working length adequacy compared to mandibular teeth. Although no significant difference was observed postoperatively between arches, a higher proportion of maxillary teeth were considered adequate in terms of root filling quality. This difference was attributed to a relatively greater incidence of curved and narrow root canals in mandibular molars, which may reduce the accuracy of electronic apex locators [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Additionally, the proximity of canals and anatomical superimpositions in mandibular molars may present challenges in access and visibility for the clinician.\u003c/p\u003e\u003cp\u003eIn a study, the cases with primary root canal fillings of acceptable quality by group were 34.2% for anterior, 23.8% for premolars, and 16.2% for molars [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Similarly, in the present study, the preoperative acceptability rates were 25%, 32.1%, and 25%, respectively. Postoperatively, these rates increased to 81.25%, 88.9%, and 87%. This improvement may be attributed to better working length control and higher density of fillings in all tooth groups.\u003c/p\u003e\u003cp\u003eIn this study, working length adequacy significantly improved in all groups except maxillary anterior teeth, increasing from 62.5%, 35.7%, and 31.25% (preoperatively) to 87.5%, 88.9%, and 87% (postoperatively) in the anterior, premolar, and molar groups, respectively. In another study, adequacy rates for working length were reported to be 55.9%, 44.4%, and 27.9%, respectively [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. These findings indicate that molars tend to have root canal fillings that do not fit the quality standards emphasised by the ESE criteria, likely due to their complex anatomy.\u003c/p\u003e\u003cp\u003eWhen the taper of primary root canal fillings was evaluated in our study, it was 50% for anterior, 64.3% for premolars, and 65.6% for molars, increasing to 93.75%, 100%, and 96.8% postoperatively. Adequacy in density rates preoperatively were 31.25%, 46.4%, and 28.1%, increasing to 100%, 100%, and 93.5% postoperatively. A study evaluating root canal treatments performed by dental students found that mandibular molars had the most acceptable taper and density values [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]; however, in another study conducted more recently, adequacy in taper was found to be 80%, 78%, and 44%, and in density was 75%, 70%, and 40% for anterior, premolar, and molar teeth, respectively [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Greater quality that meets the ESE standards was detected postoperatively in the present study owing to the retreatments being performed by experienced clinicians, suggesting that treatment outcomes may improve when performed by specialists. However, further research is required to support this observation.\u003c/p\u003e\u003cp\u003ePreoperatively, missed canals were most commonly observed in maxillary molars (58.3%), which is consistent with the literature 40.1\u003cb\u003e%\u003c/b\u003e [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]; 71.8\u003cb\u003e%\u003c/b\u003e [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Among these teeth with missed canals, periapical lesions were present in 50% of cases in the present study. Missed canals are known to negatively affect periapical tissues and increase the prevalence of lesion development.\u003c/p\u003e\u003cp\u003eIn this study, 51.31% of the teeth requiring retreatment showed preoperative periapical lesions. Previous studies reported the prevalence of apical periodontitis in root-filled teeth ranging from 31.7% to 72.1% [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. In our study, mandibular premolars showed the highest rate of preoperative periapical lesions; likewise, the literature has more commonly reported molars [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], likely due to the greater technical difficulty associated with their complex anatomy. Because the number of follow-up cases was insufficient, no postoperative periapical status could be reported for sRCTs in the present study. Among the cases with pRCTs that fit the ESE criteria in terms of radiographic root canal filling quality, periapical lesions were still detected in 23.8% of the cases. According to the literature, this rate ranges between 10.2% and 25.2% [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. These findings suggest that high technical quality alone does not guarantee treatment success, which must be consolidated by managing canal anatomy complexity, disinfection, longevity and sealing of the coronal restoration, and other required clinical parameters that significantly influence treatment outcomes.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eWithin the limitations of this retrospective study, it was observed that root canal retreatment procedures led to a statistically significant improvement in the radiographic quality of root canal fillings compared to the preoperative condition. However, the fact that ideal technical standards were not achieved in all cases reveals the challenges and technical sensitivity required for retreatment procedures.\u003c/p\u003e\u003cp\u003eThe findings of this study highlight the critical importance of accurately determining the working length, followed by sufficient cleaning and shaping, and providing a three-dimensional root canal filling in retreatment cases. Additionally, factors such as undetected missed canals in primary root canal treatments and the presence of residual filling material during retreatment must be carefully considered for their impact on postoperative success.\u003c/p\u003e\u003cp\u003eAlthough the findings suggest that performing root canal retreatments by experienced clinicians may improve radiographic quality, this must be further supported by prospective studies that include clinical examination and follow-up.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eESE\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eEuropean Society of Endodontology\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eRCT\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRoot Canal Treatment\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003epRCT\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePrimary Root Canal Treatment\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003esRCT\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eSecondary Root Canal Treatment\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003eThis study was approved by the Noninvasive Research Ethics Committee of Dokuz Eylül University, Faculty of Medicine (8847-GOA).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInstitutional consent was obtained from all patients treated at Dokuz Eylul University Department of Endodontics, DEU Oral and Dental Health Application and Research\u0026nbsp;Centre\u0026nbsp;(Noninvasive Research Ethics Committee of Dokuz Eylül University, Faculty of Medicine (8847-GOA)). Data were anonymized prior to analysis to ensure the protection of patient confidentiality.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003c/strong\u003eA written informed consent for publication was obtained from all patients treated at Dokuz Eylul University, Department of Endodontics, DEU Oral and Dental Health Application and Research Centre.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;The datasets used and/or analyzed during the current study are available in the institutional archive of Dokuz Eylul University, Department of Endodontics. Data can be obtained from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003cbr\u003e\u0026nbsp;\u003c/strong\u003eWe declare that the authors have no competing interests as defined by BMC, or other interests that might be perceived to influence the results and/or discussion reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that this work was not supported or funded by any organization, agency, or institution.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;B.S. has written the entire manuscript, performed the data collection,\u003c/p\u003e\n\u003cp\u003eO.E. set the hypothesis, performed data collection and literature review.\u003c/p\u003e\n\u003cp\u003eB.A. \u0026nbsp;performed data collection and evaluation, and proof reading.\u003c/p\u003e\n\u003cp\u003eF.A. performed data collection and evaluation, proof reading, and statistics.\u003c/p\u003e\n\u003cp\u003eG.I. performed data collection and evaluation.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u0026nbsp;The authors declare no acknowledgements to be made for present study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePatel S, Wilson R, Dawood A, Foschi F, Mannocci F. The detection of periapical pathosis using digital periapical radiography and cone beam computed tomography \u0026ndash; part 2: a 1-year post-treatment follow-up. Int Endod J. 2012;45(8):711\u0026ndash;23.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNg YL, Mann V, Rahbaran S, Lewsey J, Gulabivala K. Outcome of primary root canal treatment: systematic review of the literature \u0026ndash; part 1. Effects of study characteristics on probability of success. Int Endod J. 2007;40(12):921\u0026ndash;39.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRuddle CJ. Nonsurgical endodontic retreatment. J Calif Dent Assoc. 1997;25(11):769\u0026ndash;96.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGorni FG, Gagliani MM. The outcome of endodontic retreatment: a 2-yr follow-up. J Endod. 2004;30(1):1\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e\u0026Ccedil;alışkan MK. Nonsurgical retreatment of teeth with periapical lesions previously managed by either endodontic or surgical intervention. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005;100(2):242\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWesselink PR. Consensus report of the European Society of Endodontology on quality guidelines for endodontic treatment. Int Endod J. 1994;27(3).\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLaukkanen E, Vehkalahti MM, Kotiranta AK. Radiographic outcome of root canal treatment in general dental practice: tooth type and quality of root filling as prognostic factors. Acta Odontol Scand. 2021;79(1):37\u0026ndash;42.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBoucher Y, Matossian L, Rilliard F, Machtou P. Radiographic evaluation of the prevalence and technical quality of root canal treatment in a French subpopulation. Int Endod J. 2002;35(3):229\u0026ndash;38.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNg YL, Mann V, Gulabivala K. A prospective study of the factors affecting outcomes of non-surgical root canal treatment: part 1: periapical health. Int Endod J. 2011;44(7):583\u0026ndash;609.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSiqueira JF Jr. Aetiology of root canal treatment failure: why well-treated teeth can fail. Int Endod J. 2001;34(1):1\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRibeiro DM, R\u0026eacute;us JC, Felippe WT, Pach\u0026ecirc;co-Pereira C, Dutra KL, Santos JN, et al. Technical quality of root canal treatment performed by undergraduate students using hand instrumentation: a meta-analysis. Int Endod J. 2018;51(3):269\u0026ndash;83.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eColombo M, Bassi C, Beltrami R, Vigorelli P, Spinelli A, Cavada A, et al. Radiographic technical quality of root canal treatment performed by a new rotary single-file system. Ann Stomatol. 2017;8(1):18.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePatel S, Brown J, Semper M, Abella F, Mannocci F. European Society of Endodontology position statement: Use of CBCT in endodontics. Int Endod J. 2019;52(12):1675\u0026ndash;77.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVukadinov T, Blažić L, Kantardžić I, Lainović T. Technical quality of root fillings performed by undergraduate students: a radiographic study. ScientificWorldJournal. 2014;2014:751274.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBierenkrant DE, Parashos P, Messer HH. The technical quality of nonsurgical root canal treatment performed by a selected cohort of Australian endodontists. Int Endod J. 2008;41(7):561\u0026ndash;70.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEl Merini H, Amarir H, Lamzawaq A, Hamza M. Periapical status and quality of root canal fillings in a Moroccan subpopulation. Int J Dent. 2017;2017:1068982.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDugas NN, Lawrence HP, Teplitsky PE, Pharoah MJ, Friedman S. Periapical health and treatment quality assessment of root-filled teeth in two Canadian populations. Int Endod J. 2003;36(3):181\u0026ndash;92.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLee AHC, Cheung GSP, Wong MCM. Long-term outcome of primary non-surgical root canal treatment. Clin Oral Investig. 2012;16:1607\u0026ndash;17.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLaukkanen E, Vehkalahti MM, Kotiranta AK. Radiographic outcome of root canal treatment in general dental practice: tooth type and quality of root filling as prognostic factors. Acta Odontol Scand. 2021;79(1):37\u0026ndash;42.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShabahang S, Goon WW, Gluskin AH. An in vivo evaluation of Root ZX electronic apex locator. J Endod. 1996;22(11):616\u0026ndash;18.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBoucher Y, Matossian L, Rilliard F, Machtou P. Radiographic evaluation of the prevalence and technical quality of root canal treatment in a French subpopulation. Int Endod J. 2002;35(3):229\u0026ndash;38.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMeirinhos J, Martins JNR, Pereira B, Baruwa A, Gouveia J, Quaresma SA, et al. Prevalence of apical periodontitis and its association with previous root canal treatment, root canal filling length and type of coronal restoration \u0026ndash; a cross-sectional study. Int Endod J. 2020;53(4):573\u0026ndash;84.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHabib AA, et al. Radiographic assessment of the quality of root canal fillings performed by senior dental students. Eur Endod J. 2018;3(2):101\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBarış SD, Han\u0026ccedil;erlioğulları D, Şahbaz BS, Erdemir A. Lisans \u0026ouml;ğrencileri tarafından yapılan k\u0026ouml;k kanal tedavilerinin kalitesinin radyografik olarak değerlendirilmesi. J Kırıkkale Univ Fac Med. 2021;26(2):120\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKarabucak B, Bunes A, Chehoud C, Kohli MR, Setzer F. Prevalence of apical periodontitis in endodontically treated premolars and molars with untreated canal: a cone-beam computed tomography study. J Endod. 2016;42(4):538\u0026ndash;41.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRouhani A, Aboutorabzadeh SM, Reyhani M, Kheirabadi N, Mortazavi S, Navabi S. Prevalence of missed canals in endodontically treated teeth: a cone-beam computed tomography study. J Clin Exp Dent. 2023;15(8):e605.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHussain MA, Singh SK, Naz S, Haque M, Shah HK, Singh A. Predictors of apical periodontitis in root canal treated teeth from an adult Nepalese subpopulation: a cross-sectional study. BMC Oral Health. 2024;24(1):400.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEl Ouarti I, Chala S, Sakout M, Abdallaoui F. Prevalence and risk factors of apical periodontitis in endodontically treated teeth: cross-sectional study in an adult Moroccan subpopulation. BMC Oral Health. 2021;21:1\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDe Moor RJG, Hommez GMG, De Boever JG, Delme KIM, Martens GEI. Periapical health related to the quality of root canal treatment in a Belgian population. Int Endod J. 2000;33(2):113\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e\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":"Acceptability, radiographic quality, retreatment, root canal filling.","lastPublishedDoi":"10.21203/rs.3.rs-7748378/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7748378/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe aim of this study was to examine radiographic quality of root canal fillings in teeth undergoing retreatment compared with primary root canal treatment.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe radiographic quality of root canal fillings was retrospectively assessed in the preoperative and postoperative stages of retreatment. Seventy-six teeth were included in the study. The radiographic quality of the treatments was evaluated in terms of length, density, and taper, based on the criteria of the European Society of Endodontology (ESE).\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAcross all teeth, 28.9% were classified as having acceptable root canal treatment quality in the preoperative phase, whereas 86.5% were classified as acceptable postoperatively. Moreover, when assessing acceptability for each parameter individually, as well as for all three parameters combined, the postoperative results were significantly more favourable.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWithin the limitations of this retrospective study, the radiographic quality of root canal retreatments demonstrated a statistically significant improvement postoperatively compared with their preoperative state.\u003c/p\u003e","manuscriptTitle":"Preoperative and Postoperative Radiographic Quality Assesment of Root Canal Retreatments: A Retrospective Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-31 15:26:22","doi":"10.21203/rs.3.rs-7748378/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-25T12:05:02+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-23T21:44:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"191277197476619676321011374501796588204","date":"2025-12-20T14:00:10+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-14T21:59:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"251701409205051850356854482225529784195","date":"2025-10-23T21:08:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"333143546643177196987067997246578223617","date":"2025-10-23T11:48:21+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-21T11:23:41+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-21T11:15:51+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-10-21T07:04:50+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-20T09:28:23+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-10-20T08:24:32+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":"057c68af-b0ae-4802-a57a-cb25aaa5984a","owner":[],"postedDate":"October 31st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-16T16:06:25+00:00","versionOfRecord":{"articleIdentity":"rs-7748378","link":"https://doi.org/10.1186/s12903-026-08051-w","journal":{"identity":"bmc-oral-health","isVorOnly":false,"title":"BMC Oral Health"},"publishedOn":"2026-03-10 16:00:19","publishedOnDateReadable":"March 10th, 2026"},"versionCreatedAt":"2025-10-31 15:26:22","video":"","vorDoi":"10.1186/s12903-026-08051-w","vorDoiUrl":"https://doi.org/10.1186/s12903-026-08051-w","workflowStages":[]},"version":"v1","identity":"rs-7748378","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7748378","identity":"rs-7748378","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}