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This study evaluated the reliability of sealer penetration measurement methods used with confocal laser scanning microscopy in correlation with the percentage of residual root filling and examined the effect of residual root-filling material on dentine penetrability after retreatment. Extracted teeth were randomly divided into different groups according to the obturation sealer used (n = 6); BioRoot RCS; MTA Fillapex; Bio-C and AH Plus. Root-filling material was removed before the secondary chemo-mechanical preparation and obturation using fluorescein labelled AH Plus. Multiple micro-computed tomography scans were obtained followed by confocal laser scanning microscopy to measure the penetration of the labelled sealer into the dentinal tubules using four different methods. Measuring sealer penetration into radicular dentine using the penetration percentage method was found to be the most reliable. Dentine penetrability during retreatment did not seem to be affected by the type of residual root-filling material., (© 2024 Australian Society of Endodontology Inc.)

Background: Evaluating the effect of different obturation techniques on postoperative pain level and radiographic healing on non-surgical endodontic retreatment (NSER) applied in a single visit in teeth with a single root canal and apical periodontitis (AP)., Materials and Methods: Sixty-three teeth from 50 systemically healthy patients (mean age 34.19 ± 9.75 years; 27 women, 23 men) were included in the study. Residual root canal filling materials were removed. All teeth were randomly divided into three groups according to the obturation technique: cold lateral compaction (CLC), continuous wave compaction (CWC), and thermoplasticized gutta-core (TGC). Pain status was evaluated using the Numerical Pain Rating Scale (NRS) in all cases. Periapical index (PAI) scores were recorded in preoperative and postoperative 6-month on the periapical radiographs. Data were analyzed as statistically (IBM, Armonk, NY, USA). The significance level was determined as p < 0.05., Results: It was found that more postoperative pain occurred in the 3rd-hour interval after CLC and CWC compared to the 7th-day interval (p < 0.05). There was no difference in postoperative pain between obturation techniques in all evaluated time intervals (p > 0.05). There was no difference in the PAI scores recorded at six months between obturation techniques for all periods (p > 0.05). Similar radiographic improvement was observed in all obturation techniques at 6-months (p > 0.05)., Conclusion: CLC, CWC, and TGC root canal obturation techniques were found to have similar efficacy after NSER in a single visit in teeth with AP at six months., Trial Registration: The research was retrospectively registered on the website www., Clinicaltrials: gov with the registration number NCT06226740 on 26/01/2024., Competing Interests: Declarations. Ethics approval and consent to participate: Approval for this study was obtained from the Clinical Research Ethics Committee of Abant İzzet Baysal University (Ethics No: 2021/236). Informed consent was obtained from all individual participants included in the study and a sample of these consents was uploaded in the related files. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: This randomized clinical trial aimed to evaluate the effect of intracanal cryotherapy with 2-4 °C normal saline irrigation on post-operative pain after single-visit non-surgical root canal retreatment., Methods: Forty-six single-rooted, single-canal teeth requiring non-surgical root canal retreatment were randomly assigned to two groups (n = 23): a cryotherapy group and a control group. All the treatments were completed during a single visit. A combination of nickel-titanium and stainless-steel files was used for the removal of gutta-percha and root canal preparation, and irrigation was performed using 5.25% NaOCl and 17% EDTA. The cryotherapy group had a final irrigation temperature of 2-4 °C for 5 min before root canal obturation, whereas the control group received irrigation at room temperature. Post-operative pain levels were assessed via the Numerical Rating Scale at 6, 18, 24, 48, 72, and 168 h (up to 7 days). The number of analgesics consumed at the same intervals was also recorded. Statistical analysis was performed using the Chi-Square test, Mann-Whitney test, and Independent Samples test, with the significance level set at 0.05., Results: There was a statistically significant difference in post-operative pain between the cryotherapy group and the control group at 6 h after treatment (P < 0.05). However, post-operative pain levels were not significantly different at 18, 24, 48, 72, or 168 h after treatment (P > 0.05). Additionally, there was no statistically significant difference between the groups in terms of analgesic intake (P > 0.05)., Conclusion: Intracanal cryotherapy can effectively reduce short-term post-operative pain, but it has no effect on long-term pain or the need for analgesics., Competing Interests: Declarations. Ethics approval and consent to participate: This retrospective study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Research Ethics Committee of the School of Dentistry- Tehran University of Medical Sciences (IR.TUMS.DENTISTRY.REC.1401.072). This study is registered on the Iranian Registry of Clinical Trials website at www.irct.ir (IRCT20211231053574N1-19/12/2022) and informed consent to participate was obtained from all of the participants in the study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The root canal systems of maxillary first molar (MFM) and maxillary second molar (MSM) variations represent a clinical challenge for endodontists, especially the prevalence of fused C-shaped roots. Having a thorough knowledge of root canal configuration is an extremely important point for a successful root canal treatment to avoid missing extra canals. The aim of this article was to present 2 cases of maxillary molar with an unusual C-shaped configuration diagnosed during root canal retreatment/treatment and conduct a literature review of the MFM and MSM anatomy. Case 1 reports that three separate palatal root canals fused into a C-shaped configuration in the MFM, which with an enamel pearl in the furcation, was classified as Type D and first reported in MFM. Case 2 reflects the fusion of all three buccal canals of the MSM into a C-shaped configuration that finally formed an apical foramen with a supernumerary tooth, and the configuration was Type B. Evaluation at an 18-month and a 9-month recall revealed that two patients were symptom-free after the conduct of a non-surgical retreatment/treatment, and the X-ray revealed normal periapical tissue. In addition, the thickness of the Schneiderian membrane due to odontogenic maxillary sinusitis returns to normal after an effective retreatment in case 1. These reports serve to remind endodontists of the importance and complexity of anatomical variations, which should always be considered when formulating an effective root canal treatment plan. The combined use of cone-beam computerized tomography (CBCT) and a dental operating microscope (DOM) will be profitable to locate and identify extra canals when a periapical radiograph shows signs of an unusual canal morphology., Competing Interests: Declarations Ethics approval and consent to participate The clinical operation involved in this case was told to the patients and got the informed consent from the patients and totally approved by the Ethics Committee of Stomatological Hospital of Xiamen Medical College. All authors and patients have read and agreed to the published version of the manuscript. Consent for publication Written informed consent from patient has been taken. All authors and patients have read and agreed to the published version of the manuscript. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Background: Infected dentinal tubules are a possible source of bacteria that are responsible for the failure of root canal treatment. Therefore, disinfection of dentinal tubules by increasing the penetration of the irrigation solution is important for success in retreatment cases. This study utilized confocal laser scanning microscopy (CLSM) to assess and compare the impact of XPR, ultrasonic irrigation (UI) and sonic activation (SA) on NaOCl penetration into dentinal tubules following endodontic retreatment., Methods: A total of forty mandibular premolars were enrolled in this investigation. Following root canal preparation up to ProTaper X3 file (30/0.07), root canals were obturated with gutta-percha and bioceramic root canal sealer with single cone technique. The root canal filling materials were removed using ProTaper nickel-titanium rotary retreatment files until the working length was reached. The retreatment procedure was finalized using the ProTaper Next X4 (40/0.06). The teeth were divided into four groups based on the irrigation activation technique: control (conventional needle irrigation), SA, UI and XPR. During the final irrigation procedure, Rhodamine B dye was introduced to 5% NaOCl for visualization via CLSM. Subsequent to image acquisition, the maximum penetration, penetration percentage, and penetration area were calculated. Data were statistically analyzed using the Kruskal-Wallis, Friedman, and Bonferroni Dunn multiple comparison tests through R software (p < 0.05)., Results: In the middle third, UI yielded a significantly higher penetration percentage than the control group (p < 0.05). The UI and XPR groups showed increased penetration percentages in the coronal and middle thirds compared with the apical third (P < 0.05). Maximum penetration was notably reduced in the apical third than in comparison with the coronal and middle thirds in all groups (p < 0.05). In the control, SA and XP groups, the penetration area was ranked in descending order as coronal, middle and apical (p < 0.05). Conversely, in the ultrasonic group, the penetration area was significantly lower in the apical third than in the middle and coronal thirds (p < 0.05)., Conclusions: UI enhanced the penetration percentage in the middle third of the root compared with that in the control group. XPR and SA showed no significant effect on NaOCl penetration following retreatment., (© 2024. The Author(s).)

Introduction: Root canal retreatment is carried out in cases where previous endodontic therapies failed and involves the removal of root canal filling materials, followed by cleaning, shaping, and obturating of the canals., Aims: : The objective of this study was to collect information regarding attitudes, methods, and materials employed during the non-surgical endodontic retreatment (NSER) by general dentists working in Sousse Governorate, Tunisia., Materials and Methods: A descriptive cross-sectional survey was conducted among 147 general dentists working in the Sousse Governorate, Tunisia, from May to November 2021. Data were collected by sending a structured questionnaire to the dental practitioners through email. All the data were analyzed by using the SPSS 10 computer software., Results: A total of 96 dentists responded to this survey. The response rate was 63.5%, with a female predominance (53.2.3%). 81.2% of the respondents performed at least one non-surgical endodontic retreatment (NSER) weekly. Our study revealed that the mandibular first molar is the tooth that most often requires endodontic retreatment (83.5%). Half of the participants never used the rubber dam during this procedure. Moreover, the majority of respondents (61.9%) simultaneously used manual files and rotary nickel-titanium instruments for root canal desobturation. Most of the dentists (69.57%) systematically use solvents during root canal desobturation., Conclusion: Our survey highlights that the majority of general dentists have adequate knowledge about endodontic retreatment. Nevertheless, dentists are yet to start the application of these newer strategies towards the management of endodontic failures., Competing Interests: The authors declare there is no conflict of interest in this work., (© 2024 Kaliaperumal et al.)

Background: To evaluate the accuracy of the electronic apex locators (EALs), and Cone-Beam Computed Tomography (CBCT) scanning, both in working length (WL) determination and in the detection of root canal perforations in retreatment cases., Methods: Sixty human mandibular premolars were selected. After crown removal partially and canal access, root canals were instrumented and irrigated. The obturation process utilized gutta-percha and sealer with warm vertical compaction. Two groups were distinguished: one without perforation (Group 1) and the other with an apical third perforation (Group 2). Retreatment included filling removal, apical preparation, and irrigation. Actual working lengths (AWL) were determined using a stereomicroscope. CBCT images were used to measure CBCT working length (CWL), with adjustments for optimal views. Propex II and Dentaport ZX were used to measure electronic working length (EWL). Differences between EWL and AWL, as well as CWL, were analyzed to gauge accuracy. Data underwent Two-way ANOVA analysis. Measurements within ± 0.5 and ± 1 mm tolerance ranges were deemed successful for each device, followed by applying the Pearson Chi-square test., Results: The study reveals no significant inter-group variations in device performance (p > .05). Dentaport ZX missed detecting perforation in two Group 2 (apical perforation) cases. For ± 1 mm tolerance, Propex II displayed the highest success in Group 2 (apical perforation)., Conclusion: This study demonstrates the comparable performance of Propex II, Dentaport ZX, and CBCT in endodontic retreatment, providing insights into diagnostic reliability., (© 2024. The Author(s).)

The removal of fiber posts for the retreatment of root canals can be challenging. An autonomous robotic (ATR) system was used for accurate and minimally invasive endodontic retreatment in a patient who presented with symptomatic apical periodontitis and pain emanating from the mandibular left first molar, which had been previously restored with 3 fiber posts. Intraoral scanning data, radiographic data, and bur sizes were integrated into preoperative software program to design a treatment plan. The ATR system enabled precise and efficient post removal. The remnant filling material was removed before endodontic retreatment, and radiographs at 3 months after the procedure showed satisfactory healing. This treatment demonstrated the accuracy and efficiency of the ATR system for the removal of fiber posts from pretreated teeth, while minimizing the duration of the procedure and avoiding excessive tissue removal., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Introduction: Apical periodontitis is one of the common dental diseases. Microorganisms are the main reasons for these lesions; irrigations are used to remove them, but because of limited penetration, the rinsing agents may not always kill the microorganisms. Laser irradiation is effective in canal disinfection. The goal of this study was to compare the effect of calcium hydroxide (Ca(OH) 2 ) and diode laser on the improvement of apical periodontitis following root canal retreatment (RCR). Methods: Twenty-four teeth of 19 patients with periapical lesions which needed RCR were divided into two groups (Ca(OH) 2 and Ca(OH) 2 +laser irradiation [LI]). In the first session, after gutta-percha removal, cleaning, and shaping, Ca(OH) 2 was used for 10 days. In the second session, in the Ca(OH) 2 +LI group, the irradiation utilizing a diode laser (using non-initiated 200-µm fiber, continuous wave (CW), power output of 1W) was done. The periapical radiographic healing was assessed before the retreatment and after 3-month and 6-month follow-ups by periapical index (PAI) Qrstavik. The quantitative data were analyzed ( P <0.05). Results: The initial periapical lesion score was 3.75 and 3.88 in the Ca(OH) 2 and Ca(OH) 2 +LI groups, respectively. In the Ca(OH) 2 and Ca(OH) 2 +LI groups, 3 months after the RCR, the average periapical lesion score was 2.94 and 3.05, respectively. In the Ca(OH) 2 and CA(OH) 2 +LI groups, 6 months after the RCR, the average periapical lesion score was 1.80 and 1.75, respectively. No significant differences were found at the 3 and 6 months between the experimental groups. Conclusion: The diode laser can reduce the periapical lesion, but there was no significant difference between CA(OH) 2 +LI and Ca(OH) 2 at 3-month and 6-month follow-ups., Competing Interests: The authors deny any conflicts of interest., (Copyright © 2024 J Lasers Med Sci.)

Objective: The purpose of this in vitro investigation was to assess the effectiveness of various gutta-percha retrieval methods in endodontic retreatment., Methods: Five groups were randomly allocated to extract human teeth that had already had root canal therapy: manual files, rotary tools, heat, solvents, and ultrasonics. By evaluating the amount of filling material still present, gutta-percha clearance was quantitatively examined, and root canal cleanliness was qualitatively appraised. To compare the effectiveness of retrieval approaches, statistical analysis was done., Findings: Hand files, heat, and solvents were less effective than rotary devices and ultrasonics at removing gutta-percha ( P < 0.05). A quantitative investigation showed that the groups using rotary instruments (0.87 mm) and ultrasonics (0.68 mm) had much less gutta-percha left. The qualitative evaluation revealed that rotary instruments (2.12) and ultrasonics (2.45) had greater cleaning ratings compared to other methods., Conclusion: In conclusion, gutta-percha can be effectively removed during endodontic retreatment by using rotary tools and ultrasonics, which provide both quantitative efficiency and qualitative purity. The implementation of sophisticated retrieval procedures to maximize treatment results in clinical practice is supported by these findings., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Pharmacy and Bioallied Sciences.)

Background: Endodontic retreatment is crucial for preserving dental health but is influenced by various factors., Objective: This research aimed to assess factors affecting the success of endodontic retreatment procedures., Methods: A retrospective analysis was conducted on 250 cases of endodontic retreatment. Demographic and clinical data were collected, and treatment success was defined based on predetermined criteria. Statistical analysis was performed to evaluate associations between treatment factors and retreatment outcomes., Results: The overall success rate was 75%. Rotary instrumentation, gutta-percha obturation, and use of intracanal medication were significantly associated with higher retreatment success rates ( P < 0.05)., Conclusion: Factors such as instrumentation type, obturation material, and intracanal medication significantly influence endodontic retreatment success. Understanding and optimizing these factors are crucial for improving treatment outcomes and patient satisfaction., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Pharmacy and Bioallied Sciences.)

Objective: The purpose of this retrospective study was to assess the variables affecting endodontic retreatment technique success., Methods: A 5-year period of 500 patient records from a dental clinic were examined. Pre-operative factors, procedure specifics, post-operative results, and demographic information were all documented. The study employed statistical analysis to determine the important factors that influence retreatment success., Findings: The average age of the study group was 45.2 years, and 56% of the participants were female. Sixty-four percent of patients had multiple root canals, and the most frequent initial diagnosis (60%) was apical periodontitis. The results of the surgery varied: 50% of patients had full healing, 30% had partial healing, and 20% had no improvement at all. Significant indicators of retreatment success were found to include age, initial diagnosis, and root canal morphology ( P < 0.05)., Conclusion: The effectiveness of endodontic retreatment operations is mostly influenced by age, apical periodontitis, and root canal morphology. Optimizing treatment results requires individualized treatment techniques based on each patient's unique features. Clinicians can benefit greatly from these findings in terms of increasing endodontic retreatment success rates and enhancing patient care., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Pharmacy and Bioallied Sciences.)

Both root canal sealer-based and supplementary protocols may influence removal of filling material during endodontic retreatment. Mesial root canals of extracted mandibular molars were prepared using HyFlex EDM 25/.08, and filled with a calcium silicate sealer (Bio-C Sealer), or an epoxy resin (AH Plus), using the single cone technique (n = 12). Retreatment was performed using ProDesign Logic (PDL) RT and PDL 35/.05. The specimens were randomly divided into two experimental groups (n = 12), and the sealers were distributed similarly. A supplementary protocol was performed with PDL 50/.01 or XP-endo Finisher. Root canal transportation and volume, in addition to the remaining filling material percentage were evaluated using high-resolution (5 µm voxel size) micro-CT. Statistical analysis was performed using t-tests (α = 0.05). Root canals filled with AH Plus presented high residual filling material (p < 0.05). Both protocols decreased residual volume of filling material in the apical third (p < 0.05). PDL 50/.01 increased the apical root canal volume (p < 0.05). No difference was observed between the systems regarding canal transportation (p > 0.05). In conclusion, AH Plus is more difficult to remove from the apical third than Bio-C Sealer. PDL 50/.01 and XP-endo Finisher enabled greater removal of filling materials in the apical third, in the retreatment of curved root canals, without promoting apical transport.

Introduction: Endodontic retreatment is essential for periapical healing, involving the removal of inadequate fillings, thorough cleaning, and new filling application to prevent leakage. This study compares the dissolving abilities of Eucalyptus, Orange, and Castor oils in the re-treatment of resin-based endodontic fillings using conventional and rotary techniques., Methodology: Thirty single-rooted human teeth were prepared and filled with gutta-percha and AH Plus sealer. They were divided into three groups (n=10) based on the solvent used (Eucalyptus, Orange, or Castor oil) and further subdivided based on the techniques used (conventional and rotary). Standardised re-treatment procedures were performed, and the amount of residual material was measured., Results: A significant difference (p<0.001) was found among the groups, indicating that both the type of solvent and the technique significantly affected the amount of residual material. The rotary technique generally left less residual material compared to the conventional technique for all solvents. Eucalyptus oil with the rotary technique showed the least residual material (mean = 5.8), while Castor oil with the conventional technique showed the most (mean = 10.2)., Conclusion: Eucalyptus oil, especially when used with rotary techniques, is highly effective in removing resin-based endodontic fillings, providing a viable and safer alternative to traditional solvents. The study underscores the importance of selecting appropriate solvents and techniques for successful endodontic re-treatment., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. S. Nialingappa Institute of Dental Sciences and Research Institutional Ethics Committee issued approval HKES/SNIDSR/IEC/SS/10/22. S. Nialingappa Institute of Dental Sciences and Research Institutional Ethics Committee reviewed and discussed your application to conduct clinical research and approved the trial to be conducted in its present form. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Siraparapu et al.)

Objectives: To evaluate and compare the efficacy of XP-endo Finisher R (FKG Dentaire, Le Locle, Neuchatel, Switzerland), EDDY (VDW Dental, Munich, Germany), and passive ultrasonic irrigation (PUI) as supplementary steps following the D-RaCe retreatment file system (FKG Dentaire) in the removal of root canal obturation material using cone beam CT., Materials and Methods: A total of 45 two-rooted permanent maxillary first premolars were selected. Following access preparation, cleaning, and shaping with Hero Shaper (Micro Mega, Besançon, BFC, France) rotary file up to 25/04%, thermoplasticized obturation was performed with TotalFill BC sealer (FKG Dentaire) and gutta-percha. The specimens were subjected to routine retreatment using the D-RaCe retreatment file system. Cone beam computed tomography (CBCT) and volumetric analysis were performed before and after this procedure. The samples were divided into group A (XP-endo Finisher R: n=15), group B (EDDY: n=15), and group C (PUI: n=15). Finally, a third CBCT was taken and a volumetric analysis was done. Statistical analysis was done using SPSS Statistics version 26.0 (IBM Corp., Armonk, NY, USA)., Results: The lowest mean residual volume of obturation material was seen with XP-endo Finisher R (1.6 mm 3 ), followed by PUI (1.7 mm 3 ). The EDDY showed the least efficiency in complete debridement of the root canals (3.6 mm 3 ). This difference in values was statistically significant., Conclusion: The XP-endo Finisher R and PUI showed superior performance than EDDY in the removal of remaining obturation material from the root canal system after retreatment with the D-RaCe retreatment file system. However, none of the systems were able to completely remove the root canal obturation materials., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Ethics Committee of Malabar Dental College and Research Center issued approval IEC/04/CONS-B/MDC/2020. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, N et al.)

Introduction: This study aimed to evaluate and compare postoperative pain (PP) in single-visit nonsurgical endodontic retreatment (SV NSER) with 2% chlorhexidine (CHX), 0.1% octenidine (OCT) with or without ozone, and 5.25% sodium hypochlorite (NaOCl)., Materials and Methods: In this randomized, parallel, prospective, double-blind, clinical trial, 132 single-rooted, root-filled teeth with symptomatic apical periodontitis (AP) requiring NSER were allocated into six groups randomly (n = 22/group): 2% CHX with NaOCl (CHXH), 2% Ozonated CHX without NaOCl (OCHX), 2% Ozonated CHX with NaOCl (OCHXH), 0.1% OCT with NaOCl (OCTH), 0.1% Ozonated OCT without NaOCl (OOCT), and 0.1% Ozonated OCT with NaOCl (OOCTH). Standard NSER protocol was followed groups were irrigated with 15 ml of ozonated or nonozonated irrigant (CHX/OCT) for 3-5 min with ultrasonic agitation. PP at baseline, after 6, 12, 24, 48 h, and 7 days was recorded using the Visual Analog Scale (VAS). Logistic regression of predictor variables was compared using the Chi-square test. For group-wise and time-wise comparisons, a two-way analysis of variance followed by the post hoc Bonferroni test was carried out., Results: None of the patient-related variables in logistic regression obtained a statistically significant (P > 0.05) role in PP. The VAS score after 6 h was OCHX (4.72) > OOCT (4.42) > CHXH (4.23) > OCTH (3.95) > OCHXH (3.42) > OOCTH (3.21). OOCTH and OCHXH groups demonstrated statistically significant reductions in VAS scores at various time intervals (P < 0.05)., Conclusion: SV NSER with ozonated OCT, CHX irrigation, and NaOCl resulted in lesser PP at all time intervals, i.e., 6, 12, 24, 48 h, and 7 days in patients with symptomatic AP., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Conservative Dentistry and Endodontics.)

Aim: To evaluate cleaning efficacy and debris extrusion of supplementary file systems XP Endo Finisher (XPEF) and XP Endo Finisher R (XPEFR) in endodontic retreatment., Materials and Methods: Thirty single-rooted teeth with single canals were selected, canal preparation done till file #30 6% and obturation completed using lateral condensation technique with AH Plus sealer. The samples were stored at 37°C in a 100% humidity incubator for 7 days. The samples were distributed across the three groups according to the method of retreatment ( n = 10): Group I: Neo Endo retreatment (NER) files, Group II: NER files + XPEF, and Group III: NER files + XPEFR. Removal of gutta percha using each file system according to the distributed groups was performed. The extruded debris was collected in an Eppendorf tube, dried in a hot air oven, and weighed. Teeth were sliced longitudinally using carborundum discs. Coronal, middle, and apical thirds were assessed for cleaning efficacy under a stereomicroscope. Results were tabulated and subjected to the statistical analysis using the Kruskal-Wallis H -test followed by post hoc turkey HSD test. All statistical tests were carried out at significance level P < 0.05., Results: It was seen that Group II (NER files + XPEF) exhibited better cleaning efficacy than Group III (NER files + XPEFR), although the results were not statistically significant. Greater debris extrusion was seen with Group III when compared to Group II., Conclusion: Supplementary files XPEF/XPEFR enhance the cleaning efficacy in endodontic retreatment, but the debris extrusion of XPEFR is more than XPEF., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Conservative Dentistry and Endodontics.)

Introduction: Endodontic treatment failures often stem from the presence of microbial pathogens, particularly Enterococcus faecalis and Candida albicans . This study systematically assesses the prevalence of E. faecalis and C. albicans in endodontic retreatment cases, aiming to explore their impact on treatment outcomes., Methods: Employing a systematic sampling approach, 30 patients with a history of previous endodontic treatment were selected. Rigorous clinical and radiographic assessments were conducted, following standardized protocols for root canal sample collection. Microbiological analysis, utilizing selective culture media, was employed to identify and quantify E. faecalis and C. albicans. Statistical analyses, including chi-square and logistic regression tests, were performed., Results: The study involved 30 patients undergoing endodontic retreatment, with comprehensive clinical and radiographic evaluations for cases with and without periradicular lesions. Microbiological analysis unveiled a significant prevalence of E. faecalis and C. albicans, establishing a robust association between these pathogens and retreatment failure. These findings underscore the critical need for targeted antimicrobial interventions to enhance the overall success rates of endodontic retreatment procedures., Conclusion: This study highlights the substantial prevalence of E. faecalis and C. albicans in endodontic retreatment cases, emphasizing the importance of identifying and effectively managing these pathogens for successful treatment outcomes. The notable association between these microbial agents and retreatment failure underscores the imperative for tailored antimicrobial strategies to enhance the efficacy of endodontic retreatment procedures., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Background: During the course of a non-surgical orthograde endodontic retreatment, supplementary instrumentation is usually required for better removal of root canal filling material., Aim: The aim of this study was to assess the effectiveness of XP-Endo Finisher R in endodontic retreatment of oval root canals., Materials and Methods: The study was performed on extracted mandibular incisors preliminary cut at the cementoenamel junction. The root canals of 12 extracted lower central incisors were initially shaped with the rotary nickel-titanium system XP-Endo Shaper (30/.04) and filled with continuous waves of condensation. Root canal retreatment was performed with the МTwo Retreatment - R1 (15/.05) and R2 (25/.05) files, followed by the XP-Endo Finisher R (30/.00). Three micro-computed tomography scans were performed during the course of the experiment: 1) after the filling of the root canals, 2) after the first retreatment procedures, and 3) after the supplementary shaping. Kolmogorov-Smirnov test for normality and Friedman and Kruskal-Wallis tests for comparison of several independent samples., Results: There were no statistically significant differences in the percentage of removed obturation material in the different parts of the root canal after the use of Mtwo-R (P = 0.649) and XP-Endo Finisher R (P = 0.934). The additional instrumentation with XP-FR reduced the percentage of the remaining root canal filling insignificantly (P = 0.190)., Conclusions: The combined action of Mtwo-R retreatment files and XP-Endo Finisher R resulted in significant reduction of the amount of root canal filling material. Nevertheless, none of the examined rotary systems guaranteed its complete removal., (Copyright © 2023 Copyright: © 2023 Nigerian Journal of Clinical Practice.)

Objective: This research was aimed at assessing the effectiveness of manual H-files versus a combination of a Pro-Taper universal rotary canal preparation system and retreatment system in removing gutta-percha (GP) during endodontic retreatment, by using a digital radiography technique., Methods: This ex vivo study used a non-probability consecutive sampling technique. The study sample comprised 60 extracted anterior permanent teeth, each with one root with a straight root canal (RC). After preparation, RCs were obturated with GP and sealer. Subsequently, teeth were stored for 2 weeks in a humid environment at 37 °C. Thirty teeth each were randomly assigned to the control (group I), and experimental (group II) groups. GP removal was performed with H-files {group I) or a combination of a Pro-Taper universal rotary canal preparation system and retreatment system (group 2). Digital radiographs were acquired with Carestream digital radiovisiography software (Kodak; version-VER.6.10.8.3-A), and the presence of residual GP was analyzed. AutoCAD (2006) software was used to demarcate the RC and residual root filling. The residual GP in both groups was compared with independent sample t-tests., Results: The remaining root filling did not significantly differ when GP was removed with conventional Hedstrom files versus a combination of Pro-Taper Universal preparation and retreatment file systems. The residual GP was confined to the apical third of the canals in both groups., Conclusions: Pro-Taper Universal preparation and retreatment file systems have similar effectiveness to manual H-files in GP removal in straight canals., (© 2024 The Authors.)

Introduction Non-surgical retreatment is seen as a conservative choice for dealing with recurrent infections, instead of opting for periapical surgery. The retreatment processes should be promptly and efficiently carried out, utilizing a suitable armamentarium. The objective of this experiment is to evaluate the quantity of root dentin that remains following the removal of gutta-percha (GP) from the root canal employing two distinct retreatment files. Materials and methods Sixty single-rooted teeth were selected for the examination. The process of shaping and cleaning was performed using the step-back approach, with a master apical file size of 40. The smear layer was effectively eliminated by rinsing with a solution of 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Paper points were employed to desiccate the canals. The obturation process involved the utilization of the lateral compaction technique with the AH Plus sealer (Dentsply Sirona, NC, USA). The teeth were classified into two groups: Group I (n=30) underwent retreatment using HyFlex Remover (Coletene India, Pvt., Ltd.), whereas Group II (n=30) received therapy with Solite RS3 retreatment files (Solite Dental in Chennai, India). The remaining dentin thickness (RDT) was assessed by cone beam computed tomography at levels 3, 6, and 9 mm from the cemento enamel junction after the removal of GP. The acquired data underwent examination using an independent t-test to determine statistical significance. Results The findings demonstrate that the utilization of Solite RS3 files led to a higher level of dentin thickness remaining at 3 mm, 6 mm, and 9 mm on the mesial side in comparison to HyFlex Remover retreatment files. The observed difference was found to be statistically significant at a significance level of p<0.05 on the mesial side. Nevertheless, there was no notable disparity seen between the two file types at these three levels on the distal side (p>0.05). Conclusion Based on the obtained results of the study, it can be concluded that Solite RS3 files show promise in preserving the RDT. However, further studies encompassing diverse parameters are needed to establish a conclusive and definitive conclusion., Competing Interests: Patent application number 202241008949 for Solite RS3 endodontic retreatment rotary file., (Copyright © 2024, Sankar et al.)

Background: Root canal re-treatment (RCR) cases are considered some of the most challenging cases in the field of endodontics, as they are mostly associated with various iatrogenic errors such as ledge formation, incomplete biomechanical preparation, file separation, and incomplete obturation. These iatrogenic errors lead to defective niches within root canals that may act as reservoirs for various viable microorganisms. Such residual microbial niches may cause postoperative pain even after thorough debridement and reshaping the canals, ultimately leading to a poor prognosis for the tooth. Nowadays, prevention of postoperative pain in re-treatment cases and prognosis are effectively managed by photobiomodulation therapy (PBMT)., Method: Relevant studies in the English language published before November 2022 were identified using electronic databases like PubMed, SCOPUS, and EBSCO to conduct bibliographic research. This systematic review is based on 3 studies that were found eligible as per the inclusion and exclusion criteria. This systematic review is in accordance with PRISMA guidelines., Results: The systematic review indicated a positive impact by significantly decreasing postoperative pain in RCR cases when treated with PBMT. The variation was statistically significant at 24 hours (P = .0002), 48 hours (P = .03), and 72 hours (P = .02). The mean difference at 24 hours was 0.65 (95% CI, 0.32-0.99), at 48 hours was 0.46 (95% CI, 0.05-0.87), and at 72 hours was 0.40 (95% CI, 0.07-0.74). There was no statistical heterogenicity at 24 hours (P > .05), but a medium heterogenicity was observed at 48 hours and 72 hours., Practical Implication: PBMT or low-level laser therapy has shown superior results as compared to the conventional pharmacologic approach in postoperative pain management in RCR cases., Competing Interests: Conflict of interest None disclosed., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: No clinical studies have examined the effect of mineral trioxide aggregate (MTA) obturation levels on the outcome of endodontic retreatment. This retrospective study examined treatment outcomes in three cohorts that compared overfilling, flush filling, and underfilling after orthograde retreatment using MTA., Methods: Two hundred fifty patients with 264 teeth diagnosed with previously treated root canals and apical periodontitis retreated in a private endodontic practice were included. All teeth received MTA obturation and the extent of the final filling level was measured in relation to the major apical foramen. After 6-month follow-ups, all nonhealing cases were treated surgically. After 24- to 72-month reviews, the effect of preoperative lesion size and the degree of MTA obturation level were assessed. Multiple linear regression and time-to-event analysis using Stata 17 software (StataCorp LLC, College Station, TX) were used to evaluate the data., Results: Within the three cohorts, 99 out of 108 overfilled teeth (91.7%), 90 out of 103 flush fills (87.4%), and 10 out of 53 underfilled teeth (18.9%) healed and were successfully retreated without surgery at 48-months. When surgical outcomes were included, the combined healed proportion was 93.2%. Preoperative lesion size was found to be an important predictor for retreatment nonhealing. A 1-mm increase in lesion size at baseline resulted in an estimated 11% (95% CI 1.04, 1.18)-38% (95% CI 1.22, 1.58) increase in the risk of surgery. Compared to overfilling and flush filling, underfilling was associated with an approximately three-fold increase in requiring surgery and characterized by delayed healing., Conclusion: MTA obturation is a viable retreatment option for teeth with nonhealing endodontic treatment. MTA overfills or flush fillings do not adversely affect healing outcomes. However, MTA underfilling increases the chances for nonhealing and surgical intervention., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The success rates of NS-ReTx have varied across decades of prior research. Nonetheless, recent endodontic advances have substantially enhanced case management. This systematic review aimed to identify rigorous studies on contemporary NS-ReTx, investigating both periapical healing-evaluated strictly for complete resolution or loosely for size reduction of periapical radiolucency-and success, denoting clinical normalcy combined with periapical healing., Methods: We systematically searched MEDLINE, Embase, Web of Science, the Cochrane Library, and gray literature from January 1988 to December 2022. Article selection and data extraction were independently conducted by 3 reviewers. Selected studies underwent risk of bias assessment, and evidence quality using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Meta-analysis and meta-regression established pooled outcome rates, 95% confidence intervals (CIs), and significant clinical prognostic factors (P < .05)., Results: Twenty-nine articles were included. Pooled periapical healing rates using strict and loose criteria were 78.8% (95% CI: 75.2-82.4) and 87.5% (95% CI: 83.8-91.2), respectively. Pooled success rates using strict and loose criteria were 78.0% (95% CI: 74.9-81.2) and 86.4% (95% CI: 82.6-90.1), respectively. Meta-regression analyses revealed significant influences on NS-ReTx outcomes (P < .05), including periapical status, lesion size, apical root filling extent, and follow-up duration., Conclusions: Contemporary NS-ReTx shows encouraging outcomes, achieving periapical healing and success rates ranging from approximately 78% (strict criteria) to 87% (loose criteria). The absence of or smaller preoperative lesions, adequate root filling length, and extended follow-ups significantly improve NS-ReTx outcomes. Integrating these factors into treatment planning is pivotal for optimizing the outcome of NS-ReTx., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The present study aimed to evaluate the accuracy of four different Electronic Foraminal Locators (EFLs): Root ZX II (J. Morita, Tokyo, Japan), RomiApex A15 (Romidan, Kiryat-Ono, Israel), FinePex (Schuster, Porto Alegre, Brazil) and VDW Gold (VDW, Munich, Germany), in determining root length during endodontic retreatment steps. Twenty-seven human unirooted teeth had their crowns sectioned to standardize the teeth to 17 mm. The actual tooth length was visualized with an operating microscope and a #15 file juxtaposed to the apical foramen. Teeth were instrumented with files R25 and R40, and at the end of each instrumentation, measurements of root canal lengths were made with files #25 and #40. Then, the teeth had their root canals filled with standardized Gutta-Percha R40 cones and Endofill cement, and after seven days, they were uncovered with R25 and R40 files, respectively. New measurements were made with #25 and #40 files between the uncovering with each file. The data were statistically analyzed by ANOVA and Chi-square tests, considered significant when P <0.05. All devices tended to under-measurement when the obturating material was partially removed with the R25 file. When the canals were uncovered with the R40 instrument, the effectiveness of the appliances increased significantly ( P <0.05). At 0.40 mm diameter, the mean accuracy of the Romiapex A15 appliance was statistically lower than the other EFLs ( P <0.001), showing a tendency to over-measurement. In conclusion, all the tested appliances showed similar efficacy when acceptable limits were observed. The permanence of the remaining filling material in the apical third influenced the accuracy and efficacy of EFLs in endodontic retreatment cases. Key words: Endodontics, odontometry, apical foramen., Competing Interests: Conflicts of interest None declared., (Copyright: © 2024 Medicina Oral S.L.)

Context: Safe and efficient removal of all root filling materials from the root canal system without compromising radicular dentin structure is essential for optimal nonsurgical retreatment., Aims: The aim of this study was to evaluate and compare the incidence of dentinal defects caused during root canal filling removal using conventional, rotary, and reciprocating retreatment file systems., Settings and Design: A detailed protocol explaining purpose and procedures of the study was submitted to the Institutional Ethics Committee and ethical clearance obtained., Subjects and Methods: Sixty human maxillary permanent central incisors were collected and decoronated to 12-mm standardized length. The canals prepared up to a master apical file size F3 with Protaper hand files, obturated using AH plus sealer, examined under the stereomicroscope (×40 magnification): Group I: Control ( n = 15), Group II: Conventional ( n = 15), Group III: Protaper Universal Retreatment Files ( n = 15), and Group IV: Reciproc Blue ( n = 15). After instrumentation, teeth were sectioned at 3, 6, and 9 mm from the apex to evaluate the presence of dentinal defects under the stereomicroscope., Statistical Analysis Used: Statistics were performed using the SPSS, version, 25 (SPSS Inc., Chicago, IL, USA). Initially, normality test was done using the Shapiro-Wilk test and data were not normally distributed followed by Kruskal-Wallis test. P < 0.05 is considered statistically significant., Results: Maximum percentage increase in dentinal defects was observed in Protaper Universal Retreatment Files followed by Conventional method and Reciproc Blue., Conclusions: Significantly Reciproc Blue reduced the incidence of dentinal defects after root canal preparation., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Conservative Dentistry and Endodontics.)

Context: Complementary procedures have been proposed to improve the endodontic retreatments., Aim: The aim of this study was to evaluate, by microcomputed tomography (micro-CT), the dentin wear caused by passive ultrasonic irrigation (PUI) and easy clean (EC) instruments, when used for the final removal of filling material during endodontic retreatment., Methods: Thirty-six mesial roots of the lower first molars were divided into four groups ( n = 9), according to the final irrigation and sealer: PUI/AH Plus, EC/AH Plus, PUI/Total Fill (TF), and EC/TF. Canal volume was evaluated, both before and after the final irrigation, by micro-CT analysis. The Kruskal-Wallis test was used to compare the volumes among groups and the paired Wilcoxon test was used to compare the volume values before and after the final irrigation within each group., Results: Both complementary cleaning procedures promoted dentin wear that was observed only when the volume was analyzed for each third of the root canal. In the apical third, both instruments showed significant wear, where the use of the EC instrument resulted in greater wear than the PUI, in teeth filled with both AH Plus and TF BC Sealers ( P < 0.05)., Conclusion: Both complementary cleaning procedures promoted dentin wear and must be used cautiously., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Conservative Dentistry and Endodontics.)

Aim: Root canal treatment procedures are considered "the bread and butter" for routine clinical practice. Although retreatments have been primarily performed by endodontists (ENs), many senior practitioners and dentists who are root canal enthusiasts do opt for undertaking endodontic retreatment procedures. This survey helps us understand the practice trends and attitude of dentists undertaking endodontic retreatment procedures in and around Mumbai city., Materials and Methods: Questionnaires pertaining to endodontic retreatment were randomly distributed (hard copy/soft copy) to 1000 practicing dentists in and around Mumbai city. The questionnaire survey was divided into Part A: involving basic details such as name, demographic information, and clinical experience of the dentist and Part B: a set of questions based on assessing the trends, techniques, materials, and opinions of dentists regarding endodontic retreatment. Only those dentists who treated endodontic retreatment patients were asked to fill the Part B form. A response rate of 60.2% was achieved., Results: Out of total 602 participants, 49% of dentists (295) reported to undertake endodontic retreatment cases. Among the 295 respondents, 46.11% were Endodontists (ENs) while 53.8% were BDS or MDS of other specialties (ODs). Most dentists preferred multi-visit retreatment and prescribed antibiotics only in specific cases. Radiovisiography was the most preferred imaging aid. Calcium hydroxide and 3% sodium hypochlorite were favored choices for intracanal medicament and irrigant, respectively. Cold lateral compaction obturation technique was most common. Advanced equipment such as microscopes, loupes, ultrasonics, retreatment files, and thermoplastic obturations were more prevalent among ENs as compared to ODs., Conclusion: This study found some differences in endodontic retreatment practice trends among ENs and other dentists. But overall, most clinicians followed the international norms and are updated in recent advances in materials and techniques used in endodontic retreatment., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Journal of Conservative Dentistry and Endodontics.)

Root canal retreatment in mandibular second molars with C-shaped root canal configurations presents notable challenges. This article presents a case of successful root canal retreatment in a mandibular second molar exhibiting this complex configuration. Achieving a successful endodontic outcome in such cases necessitates a comprehensive understanding of the unique root canal anatomy. Moreover, the employment of advanced instruments and techniques is crucial to effectively address the intricacies of the C-shaped root canal system., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Liu et al.)

Introduction: Ultrasonic vibration for metallic post removal seems to be a unanimous choice between endodontists and general practitioners for providing the best results and having the highest safety. This study compared the time required by ultrasonic vibration for removing metallic post (MP) when 1 or 2 ultrasonics devices are used., Materials and Methods: One hundred and fifteen teeth with MPs from 105 patients, indicated for nonsurgical endodontic retreatment were divided into 2 groups according to the number of ultrasonic devices used (G1-1 device) and (G2-2 devices). In G1, the MP was worn with a transmetal bur, alongside the wear of the cement line (around 2 mm deep). Then, an ultrasonic tip attached to an ultrasonic unit, with a power of 100% was activated at the level of the post, with constant water spray at a level of 1 mm above the axial surface of the tooth. The position of the tip was changed between buccal and lingual surfaces every 10 seconds until the MP was removed. In G2 the same procedures were performed as described in G1, but two ultrasonic tips were activated simultaneously at buccal and lingual surfaces until the MP was removed. The vibration time necessary for removing each MP was recorded using a chronometer., Results: The mean time was 131.10±29.68 seconds (mean±standard error of the mean) for MP removal using one ultrasonic device, and 24.86±6.88 seconds for two devices. The time required for MP removal using two ultrasonic devices was significantly less than when using one ultrasonic device ( P <0.001)., Conclusion: The technique with 2 ultrasonic devices proved to be more efficient than the one using only 1 ultrasonic device., Competing Interests: None.

The persistence of apical periodontitis after endodontic therapy can be attributed to biological causes or when the treatment approaches have proven insufficient in completely eradicating the intra-radicular infection. This case report describes the endodontic retreatment of a maxillary molar in which file separation occurred during the cleaning and shaping procedure. The separated file was successfully retrieved utilizing a combination of ultrasonic and braiding techniques. The field of ultrasonics has undergone a thorough investigation and has been demonstrated to be a conservative technique with minimal radicular dentin trephination. The braiding technique is also a conservative method that involves the use of several braided H-files to apply a gripping force, facilitating the extraction of foreign bodies. The utilization of this methodology has been documented in the endodontic academic literature., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Zarekar et al.)

Statement of the Problem: Recent microbiological studies have expressed ever-increasing concerns about Candida albicans as a causal factor in the failure of endodontic treatments. Real-time quantitative polymerase chain reaction (qPCR), including the SYBR Green I system, is a technique in which a fluorescent dye is incorporated into the double-stranded DNA that is produced during DNA polymerase activity., Purpose: This study aimed to determine the relative prevalence of Candida albicans in root canals of retreatment cases and its association with endodontic symptoms., Materials and Method: In the present cross-sectional/analytical study fifty subjects were selected. Clinical features and radiographic status of the teeth were also evaluated. After access cavity preparation, the retrieved material and dentinal chips removed from the root canal were transferred into 1.5-mL microtubes, followed by storage at -20ºC until used for DNA extraction. A DNeasy Tissue Kit was used to extract DNA using the DNeasy protocol for animal tissues. Master Plus SYBR Green I (Jena Bioscience, Germany) was used in a Rotor-gene Real-time PCR System for real-time PCR. The relationship between the presence of Candida albicans and the clinical and radiographic features were analyzed using McNemar's test., Results: There was a significant relationship between the radiographic findings in endodontically treated teeth and the presence of Candida albicans . However, there was no significant relationship between the presence of Candida albicans and any of the clinical symptoms., Conclusion: In spite of the limitations of this study, we concluded that Candida albicans was associated with root canal infections in endodontic retreatment cases, but there was no relationship between root canal infections and the clinical symptoms., Competing Interests: The authors declare that they have no conflict of interest., (Copyright: © Journal of Dentistry.)

The aim of the study was to evaluate the impact of kinematics and irrigation protocols on the extrusion of apical debris during removal of different obturation techniques. A total of 144 single-rooted teeth were instrumented and obturated with Thermafil+AH Plus, Thermafil+AH Plus Bioceramic and single gutta-percha cone+AH Plus Bioceramic. Samples were divided according to the retreatment kinematics: continuous rotation or Jeni motion. Each sub-group was subjected to conventional irrigation or irrigation activated by EDDY. Extruded debris was collected in Eppendorf tubes, weighted and retreatment time was digitally recorded. Data were analysed with two-way ANOVA (p < 0.05). Debris extrusion was not significantly different between all groups. EDDY activation system and CanalPro Jeni required significantly longer time compared with other groups to remove Thermafil+AH Plus and single cone+AH Plus Bioceramic. Within current limitations, obturation technique, irrigation protocol and kinematics tested had no influence on apical extrusion debris, while they significantly impacted the retreatment time., (© 2023 The Authors. Australian Endodontic Journal published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Endodontology Inc.)

Introduction: This systematic review investigates the crucial need for solvent use in root canal retreatment, as it effectively removes filling materials, reduces apical debris extrusion, and alleviates postoperative pain, ultimately enhancing treatment success. The review aims to assess the success rates, compare outcomes, explore benefits and drawbacks, and identify subgroups where solvent use may be more effective during root canal retreatment., Materials and Methods: The search was performed in PubMed Central, Scopus, Cochrane, LILAC, ScienceDirect, Google Search, Web of Science, and manually using the search items alone and in combination by means of PUBMED search builder. The studies were assessed for eligibility according to the eligibility criteria by two independent reviewers. Groups containing solvent with nonsolvent groups and randomized control trials were included and in vitro studies, retrospective studies, and animal studies were excluded from the study. Quality assessment was performed using the risk of bias (RoB) 2.0 tool., Results: Out of the 596 articles obtained, 14 were shortlisted for full-text reading and finally two articles were included in the study. The studies were assessed for quality, and data were extracted in a tabulated form. Overall RoB is low, but due to the lack of homogeneity, meta-analysis could not be conducted., Conclusion: The use of solvent does not cause any significant difference in the postoperative pain levels or analgesic intake for retrieval of gutta-percha in cases of root canal retreatment. Due to the limited number of studies available and the lack of clinician-related outcomes such as time taken to retrieve the gutta-percha, these results should be taken into consideration with caution., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Journal of Conservative Dentistry and Endodontics.)

Aim: The purpose of the present study was to compare the efficacy of three different file systems in removing gutta-percha during endodontic retreatment with or without solvents., Materials and Methods: The current study used 120 freshly extracted, single-rooted human mandibular premolars extracted for orthodontic procedures. The canal was prepared utilizing the step-back technique and obturation was done. The samples were allocated into three experimental groups at random, group I: Hedstrom Files, group II: D-RaCe rotary system, and group III: Mtwo retreatment files system. The three groups were again split into two subgroups of 20 samples each, i.e., with solvent and without solvent. Then, a stereomicroscope with a magnification of × 20 was used to examine the samples. The amount of GP and sealer left was measured in three sections: At apical third (1 mm above the apex), middle third (8 mm from the apex), and coronal third (2 mm below the cementoenamel junction). The obtained data were analyzed using parametric Analysis of Variance (ANOVA). p -values less than 0.05 were considered significant., Results: The overall least debris on the dentinal surface was found in the middle third with/without solvent. The D-RaCe rotary system was 1.24 ± 0.11 and 1.44 ± 0.14, Mtwo retreatment files system was 1.38 ± 0.17 and 1.72 ± 0.09 and Hedstrom files was 2.08 ± 0.21 and 2.18 ± 0.16 respectively and A significant difference was found between the three different file system groups ( p < 0.001)., Conclusion: The current study concluded that, when combined with a solvent, the D-RaCe rotary retreatment system is more effective than the Mtwo rotary retreatment system and Hedstrom Files in removing gutta-percha and sealant from root canal walls., Clinical Significance: When it comes to treating chronic infections, non-surgical retreatment is a more cautious method than periapical surgery. Retreatment should be performed efficiently and with appropriate instruments to ensure effective treatment.

Aims: To evaluate and compare the treatment outcome of root filled teeth with apical periodontitis treated either non-surgically or by endodontic microsurgery, and to assess the influence of an intra-radicular post, clinical and demographic factors., Methodology: Clinical and radiological data from 1157 patients with apical periodontitis in previously root filled teeth treated by postgraduate students at the Department of Endodontics, University of Oslo, between September 2010 and January 2020 with recall data at least 11 months from completion were studied. Surgical cases were scored using the Rud/Molven criteria and grouped into success, uncertain or failure at control. Non-surgical cases were scored with the periapical index (PAI) and similarly grouped into success, uncertain or failure at control. Chi-square analyses were used for comparison of subgroups of teeth treated and logistic regression analyses for assessment of the influence of clinical variables., Results: Non-surgical retreatment was performed on 351 teeth and 107 teeth were treated with endodontic microsurgery, with overall success rates of 65.5% and 77.6%, respectively. The difference was statistically significant. Teeth with an intra-radicular post treated non-surgically (n = 30) were successful in 73.3% of cases, whereas teeth with intra-radicular post treated with endodontic microsurgery (n = 30) had a lower, 66.7% success rate. The distribution of tooth groups (anterior, premolar and molar) differed significantly between surgical and non-surgical cases, with maxillary anterior and premolar teeth more often treated surgically. Non-surgical retreatment cases were significantly influenced by patients' age (older patients had poorer outcome) and pre-operative PAI score (negatively correlated with outcome). Surgical cases were not significantly influenced by the factors studied here., Conclusions: The tooth type differed significantly for teeth treated by surgical versus non-surgical methods. Microsurgical treatment with apicectomy and retrograde filling showed significantly better treatment results than non-surgical retreatment of teeth with apical periodontitis, whereas treatment outcome in teeth with posts after non-surgical treatment tended to be better than after surgical treatment. Outcome of non-surgical retreatment was negatively influenced by older age and higher pre-operative PAI score., (© 2023 British Endodontic Society. Published by John Wiley & Sons Ltd.)

Objective: The objective of this study was to evaluate the microbiological profile of root canals indicated for endodontic retreatment due to secondary endodontic infections evidenced by the presence of chronic apical periodontitis (G1) or for prosthetic reasons, without clinical and radiographic signs of endodontic reinfection (G2)., Methods: Microbiological samples were collected from thirty teeth (N=30) out of which 15 were indicated for retreatment due to the presence of chronic apical periodontitis (G1) and 15 were indicated exclusively for prosthetic reasons (G2). Samples were collected from root canals before (S1), after chemomechanical preparation (S2), and after 30 days of intracanal medication composed of calcium hydroxide and 2% chlorhexidine gel (S3). The molecular analysis was performed using Nested-PCR for the detection of 17 bacterial species. The efficacy of each stage of the retreatment in reducing the microbial load was verified by counting colony-forming units (CFU). The statistical analysis considered a significance level of 5%., Results: The results showed that bacteria were detected in 100% of the cases in S1, in both groups, by Nested PCR. The most frequently found species in S1 in both groups were Enterococcus faecalis, Fusobacterium nucleatum, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Parvimonas micra. The microbial load of G1 was higher than G2 in the initial samples (S1). Endodontic retreatment was effective in reducing the microbial load in G1 and G2. Statistically significant associations were found between specific bacteria and clinical signs and symptoms., Conclusion: It was concluded that the microbial community present in the root canal of teeth indicated for endodontic retreatment is mixed and heterogeneous. G1 and G2 differ in the number of species per case and microbial load., Clinical Relevance: Endodontic retreatment was effective in reducing the microbial load. Statistically significant associations were found between specific bacteria and clinical signs and symptoms., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Paresthesia is a potential consequence of unsuccessful root canal treatment. Persistent infection resulting in apical periodontitis may enlarge sufficiently to involve the mental neurovascular bundle. The case presented in this report was referred for endodontic evaluation with a chief complaint of discomfort on mastication and persistent numbness of the lower left lip. Clinical and radiographic evaluation revealed incomplete primary endodontic treatment of the left mandibular second premolar with complex internal anatomy. The untreated root canal system resulted in the progression of apical periodontitis involving the left mental neurovascular bundle as confirmed by cone-beam computed tomography imaging. Nonsurgical root canal retreatment was performed over 2 visits. At the 3-year follow-up visit, the paresthesia had resolved with return of normal sensation. Nonsurgical endodontic retreatment may be sufficient to allow healing of large periapical lesions and resolve complications including paresthesia without the need for surgical intervention., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Aim: Orthograde retreatment after failed apicectomy maybe a treatment alternative to endodontic resurgery. The purpose of this study was to examine the clinical outcome of orthograde endodontic retreatment after failed apicectomy., Methodology: Success was rated radiographically in 191 cases of orthograde retreatment after failed apicectomy that were treated in a private practice with a documented recall of at least 12 months. The radiographs were rated individually by two observers, in cases of disagreement a consensus was reached by joint discussion with a third observer. Success or failure were evaluated according to previously described criteria. The success rate and the median survival were calculated using the Kaplan-Meier survival analysis. The log rank test was used to evaluate the effect of prognostic factors/predictors. Hazard ratios of predictors were analysed using Univariate Cox Proportional Hazard regression analysis., Results: The mean follow-up of the included 191 patients (124 females, 67 males) was 32.13 (±23.68) months and the median was 25 months. The overall recall rate was 54%. Cohen Kappa analysis revealed nearly perfect agreement between both observers (k = 0.81; p = 1.0). The overall percentage of success was 84.82% (complete healing 79.06%, incomplete healing 5.76%). The median survival was 86 months (95% CI: 56-86). None of the selected predictors had an influence on the treatment outcome (p > .05)., Conclusions: Orthograde retreatment should be considered a valuable treatment option after failed apicectomy. A surgical endodontic retreatment can still be a treatment option after orthograde retreatment to obtain outcome for the patient., (© 2023 British Endodontic Society. Published by John Wiley & Sons Ltd.)

Introduction: No clinical studies have examined the effect of mineral trioxide aggregate (MTA) obturation levels on the outcome of endodontic retreatment. This retrospective study examined treatment outcomes in three cohorts that compared overfilling, flush filling, and underfilling after orthograde retreatment using MTA., Methods: Two hundred fifty patients with 264 teeth diagnosed with previously treated root canals and apical periodontitis retreated in a private endodontic practice were included. All teeth received MTA obturation and the extent of the final filling level was measured in relation to the major apical foramen. After 6-month follow-ups, all nonhealing cases were treated surgically. After 24- to 72-month reviews, the effect of preoperative lesion size and the degree of MTA obturation level were assessed. Multiple linear regression and time-to-event analysis using Stata 17 software (StataCorp LLC, College Station, TX) were used to evaluate the data., Results: Within the three cohorts, 99 out of 108 overfilled teeth (91.7%), 90 out of 103 flush fills (87.4%), and 10 out of 53 underfilled teeth (18.9%) healed and were successfully retreated without surgery at 48-months. When surgical outcomes were included, the combined healed proportion was 93.2%. Preoperative lesion size was found to be an important predictor for retreatment nonhealing. A 1-mm increase in lesion size at baseline resulted in an estimated 11% (95% CI 1.04, 1.18)-38% (95% CI 1.22, 1.58) increase in the risk of surgery. Compared to overfilling and flush filling, underfilling was associated with an approximately three-fold increase in requiring surgery and characterized by delayed healing., Conclusion: MTA obturation is a viable retreatment option for teeth with nonhealing endodontic treatment. MTA overfills or flush fillings do not adversely affect healing outcomes. However, MTA underfilling increases the chances for nonhealing and surgical intervention., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to explore the influence of a framing effect in retreatment decision-making of a root-filled tooth with asymptomatic apical periodontitis (AP)., Method: Two variants of a questionnaire were created in which the factual information about a root filled with AP was identical. The options in the first variant were framed in favor to wait and see (FW) and those in the other variant were framed in favor of retreatment (FR) Two hundred and forty-eight volunteers were by chance given one of the two versions and were asked to choose between having retreatment or to wait and see., Results: Of the 125 participants given the FW version, 69 (55.2%) chose to wait and see while out of the 123 participants who were given the FR version, 38 (30.9%) made the alike choice (p = .0002)., Conclusion: A framing effect is likely to play an essential role in endodontic retreatment decision-making of root-filled teeth with asymptomatic apical periodontitis., (© 2023 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

Introduction: The nonsurgical endodontic retreatment (NERT) is the first choice of dental ministration when primary/initial endodontic treatment fails. The present study aimed to investigate the presence of postoperative pain (POP) after NERT in permanent asymptomatic teeth as well as possible factors associated with POP., Materials and Methods: A comprehensive search of literature was performed in Pubmed/MEDLINE, Embase, Scopus and Web of Science databases, up to January 2023; including randomized clinical trials and prospective studies. The risk of bias was assessed with RoB 2.0 and ROBINS-I tools. Subgroups analyses were conducted to evaluate the differences in the incidence or level of POP between the number of visits, the use/not use of solvent, the removal technique of gutta-percha, and the period of POP analysis. Mean differences and confidence intervals (CI) of 95% were used as measures of effect, and meta-regression was used along with subgroup analysis. The certainty of evidence was assessed using GRADE, and the probability value of <0.05 was considered significant ., Results: Twenty-four studies were selected, with thirteen included in the meta-analysis. There was a statistical difference between the incidence of POP after 24 h (95% CI, 0.28 to 0.52) and one week (95% CI, 0.02 to 0.13) from the endodontic retreatment ( P <0.01). However, there was no statistical difference between different techniques, number of visits and use of solvent ( P >0.05) in the same period. In addition, the certainty of evidence was very low., Conclusions: Post-operative pain is a common response to NERT, independent of the retreatment technique(s) applied, number of visits and use of solvent(s); with very low certainty of evidence as well as low risk of bias. Moreover, the current analysis showed a (very) serious risk of inconsistency and imprecision. However, POP was significantly reduced within 1 week of the NERT., Competing Interests: ‘None declared’.

Objective: Confocal laser scanning microscopy (CLSM) was used to investigate the penetration of endodontic sealers into the dentinal tubules after retreatment using two different obturation techniques., Materials and Methods: Thirty mandibular premolars were prepared up to instrument F3 (ProTaper Universal, Dentsply) and filled with Endofill using the single cone technique. The canals were retreated using Mtwo instruments. Reobturation was performed with the Bio-C sealer mixed with a fluorophore dye (Fluo-3) using either the lateral condensation technique (group LC) or the single cone technique (group SC) (n = 15). Teeth were sectioned 2, 4, and 6 mm from the apex and analyzed with CLSM to assess the penetration of the sealer into the canal perimeter and the maximum depth of penetration of the sealer into the dentinal tubules. Data were analyzed using ANOVA and the Student-t and Holm-Sidak tests., Results: In the apical segment, the penetrated perimeter was significantly higher in the LC group than in the SC group (p < 0.05); no significant difference was found in the middle and cervical segments (p > 0.05). In terms of penetration depth, no significant differences were found for any of the segments studied (p > 0.05)., Conclusion: The LC technique promoted a higher percentage of canal circumference penetrated by the sealer than the SC technique in the apical segment after endodontic retreatment., Clinical Relevance: CLSM demonstrated that the LC technique promoted a higher percentage of canal perimeter penetrated by the Bio-C sealer than the SC technique in the apical segment of mandibular premolars after retreatment., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: This study evaluated the efficiency of WaveOne Primary files (Dentsply Sirona) for removing root canal fillings with 2 types of movement: reciprocating (RCP) and continuous counterclockwise rotation (CCR)., Materials and Methods: Twenty mandibular incisors were prepared with a RCP instrument (25.08) and filled using the Tagger hybrid obturation technique. The teeth were retreated with a WaveOne Primary file and randomly allocated to 2 experimental retreatment groups ( n = 10) according to movement type: RCP and CCR. The root canals were emptied of filling material in the first 3 steps of insertion, until reaching the working length. The timing of retreatment and procedure errors were recorded for all samples. The specimens were scanned before and after the retreatment procedure with micro-computed tomography to calculate the percentage and volume (mm 3 ) of the residual filling material. The results were statistically evaluated using paired and independent t -tests, with a significance level set at 5%., Results: No significant difference was found in the timing of filling removal between the groups, with a mean of 322 seconds (RCP) and 327 seconds (CCR) ( p < 0.05). There were 6 instrument fractures: 1 in a RCP motion file and 5 in continuous rotation files. The volumes of residual filling material were similar (9.94% for RCP and 15.94% for CCR; p > 0.05)., Conclusions: The WaveOne Primary files used in retreatment performed similarly in both RCP and CCR movements. Neither movement type completely removed the obturation material, but the RCP movement provided greater safety., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported., (Copyright © 2023. The Korean Academy of Conservative Dentistry.)

Background: This systematic review investigated the effectiveness, efficiency and apical extrusion of the debris of two rotary and two reciprocating single-file systems used for the removal of filling material from straight root canals., Material and Methods: A literature search was performed in the Medline, ISI Web of Science, and Scopus databases for relevant articles matching the keyword search strategy. Effectiveness was determined with studies dealing with the ability of the instruments to remove filling material from root canals. Efficiency was assessed with studies dealing with the time needed to completely remove the root canal filling, and apical extrusion was determined with studies that measured the amount of filling material extruded through the apex., Results: From the 424 articles initially found, 406 were excluded for being non-relevant or not fulfilling the selection criteria. Another 9 articles were excluded after methodology evaluation. Finally, 9 studies were included in the systematic review., Conclusions: None of the reviewed systems is effective to completely remove the filling materials from straight root canals, and all systems appear to be equally time-efficient, although this variable shows different results. In terms of apical extrusion, the analyzed reciprocating systems extrude more material toward the periapical tissues than the continuous rotation systems. Key words: Systematic review, rotary files, reciprocating files, apical extrusion, endodontic retreatment., Competing Interests: Conflicts of interest None declared., (Copyright: © 2023 Medicina Oral S.L.)

Background: In the root canal, the tenacity of microbial infection in either or both the periradicular area is the utmost communal source of endodontic failure. The majority of the gutta percha is removed using hand and rotational equipment., Aim of Study: To determine gutta percha removal by effectively utilizing three rotary instrumentation devices all through the endodontic retreatment., Objective of Study: To determine amongst the three Nickle-Titanium systems which one is significantly effective in retreatment along with comparison of retreatment efficiency using or avoiding the utilization of solvent., Materials and Methods: On 60 newly extracted, single-rooted mandibular premolars, every root canal was sealed using gutta percha and AH Plus sealer utilizing lateral compaction. After that, the samplings were separated into three investigational groups, each with 20 specimens. After that, individual groups were separated into ten specimens. After that, the groups were withdrawn with or without solvent. ProTaper retreatment files, Mtwo retreatment files, and R-Endo files were utilized to eradicate the gutta percha after two weeks. The extent of root canal filling material left in the coronal, middle, and apical thirds was recorded utilizing a stereomicroscope and a computer image processing program. The data was statistically examined using analysis of variance., Result: The ProTaper group exhibited a smaller amount of remnant filling material than the supplementary groups in the coronal and middle thirds; however a significant difference amid ProTaper and Mtwo, and Mtwo and R-Endo in the nonsolvent groups ( P = 0.05) was concluded. In the nonsolvent group, the Mtwo group showed less leftover filling material., Conclusion: The elimination of root canal filling material was found to be equally effective in all systems. However, not a single experimental group could entirely eradicate gutta percha from the root canal., Competing Interests: There are no conflicts of interest., (Copyright: © 2022 Journal of Pharmacy and Bioallied Sciences.)

Objective: The present study was conducted to evaluate the presence of aerobic bacteria, anaerobic bacteria, E. faecalis, F. nucleatum, Propionibacteria sp., Actinomyces sp., and their reduction at various stages of endodontic retreatment with the use of conventional protocol (5.25 % Sodium Hypochlorite (NaOCl) as the irrigant along with Calcium Hydroxide (Ca (OH)2) as intracanal medicament and advocated protocol (SmearOFF as the irrigant along with 2% Chlorhexidine (CHX) gel as intracanal medicament)., Methods: Twenty eight patients fulfilling the eligibility criteria were selected for root canal retreatment and randomly allocated into two groups. Group 1: Final irrigant as SmearOFF+Chlorhexidine 2% gelas intracanal medicament (n=14). Group 2: Final irrigant as 5.25% NaOCl+Ca(OH)2 as intracanal medicament (n=14). With aseptic environment, access opening was performed followed by Gutta Percha (GP) removal and sample S1 was collected for bacterial analysis. The biomechanical preparation was done by using Reciproc system with additional finishing with XP-Endo Finisher R. Sample S2 was then collected for bacterial analysis after the final irrigation protocol in the respective groups. Intracanal medicaments were placed for one week and sample S3 was collected. All the samples were subjected to qualitative analysis using PCR and quantification was done by Colony Forming Unit (CFU) analysis., Results: Aerobic [28/28], Anaerobic [28/28], Propionibacterium sp. [20/28] and F. nucleatum [24/28] were the most frequently isolated in S1 sample followed by Actinomyces sp. [16/28] and E. faecalis sp. [19/28]. Chemico-mechanical preparation followed by irrigation (S2 sample) resulted in significant reduction of all types of bacteria in both groups. Group-1 (SmearOFF as the final irrigant) had significantly superior efficacy against aerobic bacteria, E. faecalis and F. nucleatum (P<0.05) as compared to Group-2 (NaOCl). After medicament placement, significant differences between the groups were noted only for the E. Faecalis group. For the S3 samples, the mean bacterial reduction was significant in Aerobic and F. nucleatum in S3 samples for Group 1 and Group 2., Conclusion: Chemico-mechanical preparation followed by irrigation resulted in significant reduction in bacterial load irrespective of the final irrigant. SmearOFF was significantly better than NaOCl in minimizing bacterial load of E. faecalis and F. nucleatum. 2% Chlorhexidine gel has superior antimicrobial efficacy against E. faecalis and may be recommended in secondary endodontic treatment.

Introduction: The aim of this study was to evaluate the effect of previous root canal treatment on dentinal tubule penetration of calcium silicate-based sealers during endodontic retreatment and to compare 2 different (commonly used and modified) tubule penetration depth measurement techniques., Methods: The crowns of mandibular premolar teeth were removed, and root canals were prepared (ProTaper Universal; Dentsply Sirona, York, PA) and obturated using AH Plus (AH; Dentsply DeTrey, Konstanz, Germany), MTA Fillapex (MTAF; Angelus, Londrina, Brazil), and WellRoot ST (WRST; Vericom, Gyeonggi-do, South Korea); 0.1% red Rhod-2 dye (Chemodex, St Gallen, Switzerland) was added to the sealers. After storage for 3 weeks (37°C, 100% humid), the following sealer combination subgroups were created (the sealer used during the primary root canal treatment/the sealer used during the retreatment, n = 8): AH/AH, AH/MTAF, and AH/WRST; MTAF/AH, MTAF/MTAF, and MTAF/WRST; and WRST/AH, WRST/MTAF, and WRST/WRST. Green Fluo-3 dye (0.1%) was added to the sealers during retreatment. Sealer penetration depths were measured at 8 points and averaged, and the ratio of the retreatment sealer to the initial sealer was recorded as the mean tubule penetration depth ratio in the first technique, whereas the percentage of the circumferential penetration area ratios of the retreatment and initial sealers was calculated in the second technique. Statistical analyses were performed using Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests., Results: The mean penetration depth of AH and MTFA was found to be higher at the coronal third region in the control groups (P < .05). Both methods showed a significant difference among the groups at the coronal and median regions (P < .05). The AH/WRST, MTAH/AH, MTAF/MTAF, MTAF/WRSTS, and WRST/WRST groups showed deeper tubule penetration (first technique, P = .01). Both techniques showed that the penetration depth of the sealers was the same at the apical region (P > .05), whereas a difference was found among the techniques at the coronal and median regions. The sealers used in the previous root canal treatment limited the penetration depth of the sealers used during the retreatment process (P < .05). When MTAF was used as the initial sealer, the penetration depth of the second sealer did not change, whereas if WRST was the initial sealer, the penetration depth of the sealers at the median and apical regions is negatively affected during the retreatment process (P < .05)., Conclusions: Previous root canal treatment affects the penetration depth of calcium silicate-based sealers. The use of AH Plus and MTA Fillapex during the retreatment process showed an advantage. Both measurement techniques showed similar performances at the apical region, whereas the results varied at the coronal and midcoronal regions; therefore, a more stable sealer penetration measurement technique is still necessary., (Copyright © 2022 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Statement of the Problem: The success of root canal therapy depends on root canal irrigation, disinfection, and sealing of root canal. Wettability and roughness of root dentine surface are important factors in root canal disinfection and sealing., Purpose: This study aimed to assess the effect of chloroform application on roughness and wettability of the root canal walls in endodontic retreatment., Materials and Method: This in vitro experimental study evaluated 70 sound extracted human anterior teeth. The specimens were then randomly assigned to 7 groups as follows: Chloroform (group 1), 1g gutta percha+chloroform (group 2), 2g gutta percha+ chloroform (group 3), 1g gutta percha+ 1g sealer+ chloroform (group 4), 2g gutta perch+ 2g sealer+chloroform (group 5), 1g sealer + chloroform (group 6) and 2g sealer + chloroform (group 7). One drop of distilled water was placed on each tooth to measure the contact angle and wettability. Photographs were obtained of an area measuring 50×50 µm 2 in three directions under an atomic force microscope to measure the roughness. The tooth blocks were exposed to the abovementioned mixtures for 10 min, and then rinsed with saline. The roughness and wettability of each sample were measured before and after treatment. Data was analyzed using one-way ANOVA and Tukey's test., Results: The roughness of all groups significantly decreased following treatment, except for groups 1 and 4. The contact angle increased in all groups after treatment (except for the chloroform group), which indicated decreased wettability. The roughness and the contact angle have shown no correlation., Conclusion: Application of chloroform for removal of gutta-percha and sealer in endodontic retreatment decreases the roughness and wettability of dentine., Competing Interests: The authors declare that they have no conflict of interest., (Copyright: © Journal of Dentistry.)

Objectives: The aim of retrospective study was to evaluate the changes to the periapical bone sites after non-surgical endodontic retreatment by using fractal analysis on periapical radiographs., Materials and Methods: Thirty patients whose teeth had periapical lesions and underwent primary endodontic treatment were selected for nonsurgical single-visit endodontic retreatment. Two radiographs were taken, the first immediately after retreatment and the second at the 1-year follow-up. An identical region of interest close to the infected root apex was selected from each radiograph. FD was measured using the box-counting method. Periapical status was evaluated using the periapical index (PAI). Treatment outcomes were categorized into healed (PAI < 3), or not healed (PAI ≥ 3) based on radiographic criteria., Results: The mean FD value significantly increased at the 1-year follow-up compared to baseline. No significant sex biases were apparent. According to the PAI, retreatment after 1 year resulted in a 63.3% healed., Conclusion: The extent of periapical trabecular bone evident radiographically increased, as revealed by FD data, 1 year after endodontic retreatment. Clinical relevance The use of fractal analysis as a quantitative method to evaluate changes in periapical trabecular bone (such as healing and inflammation) after endodontic retreatment can be an important marker in determining the prognosis of endodontic retreatment., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)