Purpose: The objective of this study is to investigate the distribution of complications arising during root canal treatments performed by undergraduate and postgraduate students, and to evaluate the impact of experience level on the occurrence of these complications.
Methods: The present retrospective study evaluated endodontic treatments performed by third-, fourth- and fifth-year dental students, as well as postgraduate students at the beginning of their specialty training and those in their first, second, and third years of training. A total of 1180 root canal treatments performed due to apical periodontitis were subjected to analysis. The complications were classified into the following categories: underfilling, overfilling, inadequate shaping, ledge formation, presence of fractured instruments, apical transportation, and perforation. The collected data were then subjected to analysis using IBM SPSS version 29, and differences between the groups were assessed through the implementation of the Chi-square test (p<0.05).
Results: A total of 1180 cases were examined, and the most prevalent complications were identified as underfilling (16.9%), overfilling (10.8%), and inadequate shaping (10.4%). A statistically significant discrepancy was identified in the distribution of complications among undergraduate and postgraduate students (p<0.001). Underfilling (22.8% vs. 10.9%), inadequate shaping (14.8% vs. 5.9%), and ledge formation (5.5% vs. 0.7%) were more frequently observed in undergraduate students, whereas the incidence of overfilling was higher among postgraduate students (12.9% vs. 8.7%, p=0.018).
Conclusion: The present study demonstrates that the level of experience significantly affects the incidence of complications in root canal treatment. Specifically, complications such as underfilling, inadequate shaping, and ledge formation were more frequently encountered in undergraduate students, whereas postgraduate students exhibited higher rates of overfilling. The present findings underscore the imperative for more comprehensive instruction in endodontic techniques.

Purpose: This study compared the effects of solvents (chloroform, orange oil, turpentine, eucalyptol, Endosolv R) and irrigants (5.25% sodium hypochlorite [NaOCl], distilled water) on the adhesion of glass fiber posts luted with dual-cure resin cement to root canal dentin, testing the hypothesis that solvents and NaOCl would impair bond strength.
Methods: In this in vitro study, 128 extracted human mandibular premolars were prepared, filled, and retreated using NiTi files with assigned solvents/irrigants. Post spaces were prepared, and glass fiber posts were cemented with dual-cure resin. Push-out bond strength (MPa) was measured on 1-mm-thick root slices using a universal testing machine. Data were analyzed via ANOVA and Tukey tests (p<0.05).
Results: Turpentine significantly reduced bond strength compared to control and other solvents (p<0.05). NaOCl also decreased bond strength (p<0.05), while Endosolv R, chloroform, eucalyptol, and orange oil showed values comparable to the control. The highest bond strength was observed with eucalyptol.
Conclusion: Turpentine and NaOCl adversely affected glass fiber post adhesion, likely due to solvent penetration or oxygen radical interference. Clinicians should avoid turpentine during retreatment and consider antioxidants with NaOCl. Further research on solvent-dentin interactions is warranted to optimize post-retreatment outcomes.

Purpose: This study aimed to assess the content, educational quality, and reliability of YouTube videos on endodontic retreatment to determine their usefulness for patients, students, and dental professionals.
Methods: On February 15, 2025, a YouTube search was performed using the terms “retreatment,” “repeat root canal treatment,” and their Turkish equivalents. Among 85 videos screened, 35 met the inclusion criteria. Two observers independently evaluated them using a 13-item content checklist, the Modified DISCERN (mDISCERN) tool, and the Global Score for Educational Value (GSEV). Descriptive statistics, normality tests, Spearman correlation, t-tests, and Kruskal-Wallis tests were used for analysis (p<0.05).
Results: The mean GSEV score was 5.07±3.21, suggesting moderate educational value. The average mDISCERN score was 2.44±0.95, indicating low reliability. Retreatment indications were the most commonly discussed topic (91.4%), while contraindications and intraoperative pain were rarely mentioned. Longer videos had higher GSEV scores. No link was found between video popularity and quality. Most videos were uploaded by independent dentists (57.1%).
Conclusion: YouTube videos on endodontic retreatment show inconsistent quality and limited reliability. They can offer visual support but should not replace scientific resources. Dental professionals should help direct audiences to accurate, evidence-based content.

Purpose: With the advancement of technology, both patients and healthcare professionals increasingly seek information. However, analysis of the data hosted by various platforms that allow rapid access to such information via the internet remains underexplored. This study aims to evaluate the content accuracy and educational quality of YouTube videos related to symptomatic irreversible pulpitis.
Methods: On April 5, 2024, a search was conducted on the YouTube platform using the keyword “Symptomatic irreversible pulpitis.” Initially, 610 videos were screened, but only 32 met the inclusion criteria. The videos were assessed according to five content parameters: Diagnosis, treatment, etiology, prognosis, and symptoms. Quality assessment was conducted using the Video Information and Quality Index (VIQI), which includes information flow, accuracy, technical quality, and title-content consistency. Kruskal-Wallis and Dunn’s tests were used for statistical evaluations. (significance level p<0.05).
Results: Among the 32 videos included in the study, 34.4% provided inadequate, 43.8% moderate, and 21.9% high-quality information. Videos providing moderate-quality information had a significantly higher number of likes compared to the other groups (p<0.05).
Conclusion: Most YouTube videos related to symptomatic irreversible pulpitis are academically insufficient. There is a growing need for more reliable and higher-quality digital content to be used in dental education.

Purpose: The aim of this study was to compare the effectiveness of the XP-Endo Finisher R (XPFR), sonic irrigation (EDDY) and manual dynamic activation (MDA) in enhancing the penetration of a contrast irrigation solution into the lateral canals of 3D printed teeth.
Methods: A total of 45 3D-printed teeth with lateral canals 3 mm from the root apex were used in this study. Root canals were prepared up to size #35.06. The specimens were then divided into three groups (n=15) according to the irrigation activation technique used: XPFR, EDDY and MDA. Each technique was applied using 1.5 mL of 1% methylene blue (MB) as the contrast dye. Penetration depth was assessed via images captured under a dental microscope, and scored on a four-point scale. Data analysis was performed using Kruskal-Wallis and Mann-Whitney U tests, with statistical significance set at p<0.05.
Results: Statistical analysis revealed significant differences among the groups (p=0.002). In the XPFR group, penetration of MB into the lateral canals was lower than in the EDDY (p=0.002) and MDA (p=0.008) groups.
Conclusion: EDDY and MDA techniques were more effective than XPFR in facilitating MB penetration into lateral canals of 3D-printed models.

Purpose: The aim of this retrospective study was to evaluate the degree of healing in the periapical region of teeth with chronic apical periodontitis (CAP) following initial root canal treatment (RCT) and retreatment using fractal analysis (FA) of panoramic radiographs after 2-year follow-up.
Methods: This study included a total of 136 mandibular molars, 71 initial RCTs and 65 retreatments. Teeth that were diagnosed with CAP and presented with a well-defined radiolucent periapical lesion were included in the study. Both preoperative and 2-year follow-up radiographs of ideal quality were chosen for the analysis. FA was performed using the box-counting method proposed by White and Rudolph using ImageJ 1.3 software (NIH, Bethesda, MD, USA). The data were analyzed using the Kolmogorov‒Smirnov, Wilcoxon, and Chi‒square tests and Spearman’s correlation coefficient.
Results: No statistically significant difference was found between the healing rates of the initial RCT and retreatment procedures (p>0.05). There was a statistically significant difference between the fractal dimension values measured before treatment and 2 years after treatment in patients who underwent initial RCT and retreatment procedures (p<0.05).
Conclusion: According to the FA results, the healing rate in the periapical region was similar between the initial RCT and retreatment procedures.

Purpose: The aim of this study was to evaluate the fracture resistance of endodontically treated teeth restored by direct and indirect techniques using different concentrations of NaOCl.
Methods: Seventy extracted maxillary premolars were used. Ten teeth were not treated (control group). The remaining 60 teeth were divided into two main groups, according to the type of restoration applied: composite and computer-aided design/computer-aided manufacturing (CAD/CAM) (N=30). Standard MOD cavities and access cavities were prepared, according to the groups. Teeth in each main group were divided into three subgroups according to the irrigation used (distilled water, 2.5% sodium hypochlorite (NaOCl) and 5.25% NaOCl) (n=10). During root canal preparation, each subgroup of composite and CAD/CAM was irrigated with distilled water, NaOCl with 2.5% NaOCl concentration and NaOCl with 5.25% NaOCl concentration. After root canal filling, the specimens were restored with nanohybrid composite resin and CAD/CAM technique using nanohybrid composite block. All teeth were subjected to fracture testing using a universal testing machine.
Results: No significant difference was obtained in terms of fracture strength when irrigation solutions were compared in both composite groups and CAD/CAM groups (p>0.05). The fracture strength of the teeth restored with composite resin was statistically significantly higher than the teeth restored with CAD/CAM in each distilled water, 2.5% NaOCl, 5.25% NaOCl solutions (p<0.05).
Conclusion: NaOCl irrigation solution used in root canals did not affect the fracture strength of the teeth. The fracture strength of direct composite restorations used in coronal restorations was higher than that of CAD/CAM restorations.

Purpose: To assess the effects of exposure to sodium perborate, carbamide peroxide, and hydrogen peroxide on the surface microhardness and surface morphology of ProRoot MTA and Biodentine.
Methods: A total of 50 specimens of each cement, ProRoot MTA and Biodentine, were prepared. The specimens were assigned into 5 groups based on the bleaching agent applied (n=10): A mixture of sodium perborate and distilled water (SP-DW), a mixture of sodium perborate and 3% hydrogen peroxide (SP-HP), carbamide peroxide (CP), hydrogen peroxide (HP), and control group. Bleaching agents were changed four times on every fourth day. Surface microhardness and surface morphology were assessed using a microhardness tester and scanning electron microscope, respectively. Data were analysed using two-way ANOVA and Tukey’s test.
Results: All bleaching agents caused morphological differences on the surfaces of the both cements. All bleaching agents, except SP-DW, caused a decrease in the microhardness of both cements, with HP causing the greatest decrease, followed by CP and SP-HP, respectively. Biodentine showed higher surface microhardness values than ProRoot MTA in all groups.
Conclusion: Biodentine may be recommended as a cervical barrier and a mixture of sodium perborate and distilled water may be the safest bleaching agent to preserve the surface properties of CSCs.

Purpose: This study aims to investigate the push-out bond strength of fiber-reinforced posts following passive ultrasonic activation of the post space using EDTA, MTAD, Dual Rinse, and SmearOFF as final irrigation solutions, and to classify the associated modes of bond failure.
Methods: A total of 60 human mandibular premolar teeth were instrumented and obturated using a bioceramic-based root canal sealer. Post spaces were prepared using a fiber post drill set, maintaining 5 mm of the apical canal filling remained, and the samples were randomly divided into four groups (EDTA; MTAD; Dual Rinse; SmearOFF) (n=15). Intermittent passive ultrasonic activation protocols were applied to the final rinsing solutions. Fiber-reinforced posts were cemented into the post spaces using the self-adhesive resin cement Panavia SA Cement Universal.
Results: No statistically significant differences were found among the different final irrigation protocols applied. Although there was no statistical difference in the main effect, the main effect strength was highest in the EDTA group and lowest in the Dual Rinse group. Adhesive failure was the most frequently observed failure mode, while cohesive failures were observed at the lowest level.
Conclusion: EDTA, Dual Rinse, MTAD, and SmearOFF solutions have demonstrated comparable effects for post-space irrigation.

Purpose: The aim was to evaluate the effectiveness of different irrigation activation methods in removing calcium hydroxide (Ca(OH)2) from two different root canal isthmuses (apical and middle levels) created using three-dimensional (3D) modelling.
Methods: In this in vitro study, 150 acrylic blocks were divided into 10 groups (n=15). Models fabricated and filled with pure injectable Ca(OH)2 paste (UltraCal XS, Ultradent, South Jordan, UT). Five irrigation activation groups were established (conventional needle irrigation (CNI), EDDY activation, passive ultrasonic activation, XP Endo Finisher activation and Er,Cr: YSGG laser activation). The amount of residual Ca(OH)2 in the root canal isthmus was evaluated with a stereomicroscope at ×10 magnification. All procedures were performed by a single operator. The area containing Ca(OH)2 was subtracted from the total area measurement and the cleaning percentage and area calculation were made using the Image J program. The obtained data were recorded in the Microsoft Excel program, and IBM SPSS v29 package program was used for analysis and visualization of the data.
Results: Er,Cr: YSGG laser showed significantly lower amount of Ca(OH)2 remnants compared to other methods (p<0.001). In the apical isthmus region, EDDY was the least effective method, while in the middle isthmus region, the CNI method was the least effective.
Conclusion: Er,Cr: YSGG laser-activated irrigation technique demonstrated superior efficacy in the removal of Ca(OH)2 from root canal isthmus regions than other activation methods. 3D modelling enabled the comparison of irrigation activation methods in a standardized manner.

Purpose: The aim of this in vitro study was to compare the effects of root canal irrigation agents—Dual Rinse HEDP, Propolis, and EDTA—on root dentin microhardness.
Methods: Forty human maxillary central incisors were sectioned buccolingually to yield 80 specimens. The samples were embedded in acrylic blocks; their surfaces were sanded and polished. Thereafter they were randomly assigned to four groups (n=20 each): Saline, EDTA, DR HEDP, and Propolis. Vickers microhardness measurements were performed before and after irrigation using a 100-gf load and a 10 s dwell time. Data were analyzed by one-way ANOVA followed by Student–Newman–Keuls multiple comparison test.
Results: All irrigation solutions except Saline produced a significant decrease in microhardness (p<0.05). The greatest percentage of hardness loss was observed in the Propolis group (24.24%), followed by DR HEDP (20.61%) and EDTA (19.56%). The Saline group showed no significant change (0.81%). No statistically significant differences were found among the EDTA, DR HEDP, and Propolis groups (p>0.05).
Conclusion: Although not statistically significant, Dual Rinse HEDP caused a greater decrease in root dentin microhardness than EDTA.

Purpose: This study aimed to investigate the association between individuals’ circadian typology and oral health status, as measured by the Decayed, Missing, and Filled Teeth (DMFT) index, as well as the prevalence of endodontic treatment.
Methods: Chronotypes were determined using the Morningness-Eveningness Questionnaire, which was administered through face-to-face interviews. The questionnaire comprised 26 items and was completed by 349 participants. In addition, each participant’s oral health status was evaluated by recording their DMFT index and the presence of endodontically treated teeth through clinical examination and dental records. Statistical analyses of continuous variables, including means and standard deviations, were conducted using chi-square and analysis of variance tests. A p-value of <0.05 was considered to indicate statistical significance.
Results: No statistically significant differences were observed among the three chronotype groups (morning-, intermediate-, and evening-types) regarding the mean number of endodontically treated teeth (p>0.05). However, a significant difference in DMFT scores was found across the chronotype groups (p<0.05), with the lowest values observed in morning-types (4.14±1.952) and the highest in evening-types (5.48±2.686).
Conclusion: The results suggested that circadian rhythm may influence oral health status. Specifically, individuals with an evening-types appear to exhibit a greater predisposition to dental caries, which may increase their risk of requiring endodontic treatment if caries remain untreated.

Purpose: This systematic review and meta-analysis aimed to determine the prevalence of root canal dilaceration in Türkiye and the world. Additionally, the difference in the prevalence of root dilaceration between Türkiye and the world population has also been examined.
Methods: This systematic review and meta-analysis was registered with the Open Science Framework (OSF) to ensure transparency and reproducibility of the research process (Registration DOI: https: //doi. org/10.17605/OSF.IO/5UBKA). Our study was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statements. The MeSH terms and keywords were used to search articles published in three electronic databases PubMed, Web of Science, and Scopus. The search strategy was limited to English and Turkish articles published before 12 December 2024. In addition, the bibliographic references of the qualifying papers were manually searched. Data were collected according to the inclusion and exclusion criteria. The included studies were assessed by two independent reviewers using the Joanna Briggs Institute’s critical appraisal checklist for prevalence studies.
Results: Forty-four observational studies are included in this meta-analysis. 35435 patients and 103948 teeth were examined in these studies. The overall prevalence of root dilaceration was 9.1% (95% CI=0.065-0.125) in patients and 2.3 % (95% CI=0.016-0.035) in teeth. We found the prevalence of root dilaceration to be 5.2% (95% CI=0.029-0.09) in Türkiye. There was no statistically significant difference between the prevalence in Türkiye and the world when comparing studies that assessed the number of patients with dilaceration (P=0.0545). However, there was a statistically significant difference when comparing studies that focused on the number of dilacerations of teeth (P=0.03).
Conclusion: Within the limitations of this meta-analysis, root dilaceration was observed in 9.3% of individuals and 3.1% of teeth globally, with a lower prevalence (5.2%) identified in Türkiye. Due to the diagnostic and therapeutic challenges posed by such teeth, accurate diagnosis and well-structured treatment approaches are essential. Further research utilizing standardized diagnostic criteria and including diverse population samples is needed to clarify the underlying causes and enhance clinical management strategies.

Regenerative endodontic treatment is a biologically based procedure primarily indicated for the management of necrotic immature permanent teeth. Beyond achieving the resolution of periapical radiolucencies and the elimination of clinical symptoms, RET aims to promote continued root development, including the thickening of dentinal walls and apical closure, and ideally, the re-establishment of pulp vitality. This case report presents two clinical cases treated with regenerative endodontic protocols, with follow-up periods of 30 months and 12 months, respectively. The first case involves a maxillary lateral incisor that underwent a repeated regenerative procedure, while the second case pertains to a maxillary central incisor with a history of dental trauma and prior conventional root canal treatment. The irrigation protocol consisted of 1.5% sodium hypochlorite, followed by distilled water and 17% ethylenediaminetetraacetic acid. Calcium hydroxide was employed as the intracanal medicament. Biodentine (Septodont, France) was used as a coronal barrier, and definitive restorations were completed with composite resin. During the follow-up period, a secondary regenerative procedure was performed for Case 1 at the 18-month recall. At the 30-month follow-up for Case 1 and the 12-month follow-up for Case 2, both cases exhibited radiographic evidence of periapical healing and remained asymptomatic. However, both teeth yielded negative responses to pulp vitality testing and cold stimuli. Regenerative endodontic treatment is considered a promising alternative to apexification therapy for immature and necrotic teeth.

The mandibular molars are often conferred with varied anatomies and are more prone to be subject to an endodontic intervention. Therefore, familiarity with these varying aberrant morphologies is of utmost importance to an endodontist. The complex anatomy of permanent mandibular molars, particularly the existence of the middle mesial canals (MMCs), presents significant challenges in endodontic treatment. MMCs can be classified into one of the three types: Fin, confluent, and independent, with the last being the rarest. Inadequacy to identify and treat these canals can precipitate persistent infection and subsequent endodontic failure. This article presents three clinical cases elucidating the detection and management of MMCs in permanent mandibular molars. Advanced diagnostic techniques, including magnification, ultrasonic troughing, and cone-beam computed tomography, can be diligently used to locate and negotiate these canals. All cases involved meticulous cleaning, shaping, and obturation, resulting in successful outcomes. The discussion emphasizes the importance of a systematic approach to canal exploration, the use of modern imaging modalities, and conservative instrumentation to preserve root integrity. The identification and treatment of MMCs are critical for predictable endodontic outcomes. This article underscores the significance of MMCs in endodontics and provides practical in-sights for their management.