Purpose: This study aimed to evaluate the effect of different canal shaping and obturation techniques on retreatment efficacy by analyzing the weight of removed filling material, retreatment time, and surface area reduction.
Methods: Eighty standardized acrylic resin blocks were shaped using four endodontic file systems [Pro-Taper Next (PTN), ProTaper Ultimate (PTU), VDW Rotate (VR), and XP-endo Shaper (XPS)] and obturated with either single-cone (SC) or continuous wave compaction (CWC), forming eight experimental groups (n=10). All samples were retreated using a single-file system. The amount of removed material was measured with a precision balance, time was recorded in seconds, and surface cleanliness was assessed using ImageJ software. Data were analyzed using the Kruskal–Wallis test followed by Bonferroni-adjusted pairwise comparisons.
Results: Statistically significant differences were found among groups for all parameters. XPS/SC and PTN/SC removed significantly more filling material than PTU/CWC and XPS/CWC. Retreatment times were significantly longer in XPS/SC and PTN/SC, and significantly shorter in PTU/CWC and XPS/CWC. For surface area reduction, PTU/CWC and XPS/CWC achieved the highest values, with CWC groups generally outperforming SC groups in cleanliness. Weight reduction correlated positively with time, while time correlated negatively with surface area reduction.
Conclusion: Retreatment efficacy is significantly influenced by the initial shaping and obturation technique. CWC generally resulted in shorter retreatment times and greater surface cleanliness, whereas SC groups tended to have greater filling removal by weight.

Purpose: The present study aims to compare the radiographic technical quality of root canal fillings performed on 3D-printed resin and extracted natural teeth, and to examine the agreement between endodontist educator assessment and analysis performed by an artificial intelligence-based chatbot (ChatGPT-4o).
Methods: After theoretical training and practical demonstration, 3rd-year undergraduate students performed root canal treatment on 108 printed resin teeth and 108 extracted natural teeth. In the radio-graphic examination, parameters such as root canal filling length, filling continuity, apical transport, perforation, and instrument fracture were evaluated by both an experienced instructor and ChatGPT-4o. The technical quality of root canal filling and all procedural errors were compared between the printed teeth and extracted teeth groups using the chi-square test. Interexaminer reliability was measured between the instructor and ChatGPT-4o.
Results: Regarding overall root canal quality, 34% of extracted teeth were acceptable and 66% were unacceptable, while 45% of printed teeth were acceptable and 55% were unacceptable. There is no statistically significant difference between the acceptability rates of extracted teeth vs printed teeth (p>0.05). It was observed that the extracted teeth had more under-filled canals and fewer adequately filled canals than expected, whereas printed teeth were more likely to be adequately filled (p<0.05). There was no difference between sample types having adequate or inadequate filling continuity (p>0.05). Apical transportation, perforation, and instrument fracture rates did not differ significantly between extracted and printed teeth. Cohen’s kappa value is 0.210, and the inter-observer agreement was 62%. These results indicated low agreement between the instructor and ChtaGPT-4o significantly (p<0.05).
Conclusion: The overall quality of the canal filling applied by undergraduate students on 3D-printed resin and extracted teeth was similar. ChatGPT-4o evaluation did not demonstrate a high level of agreement with the endodontist instructor.

Purpose: The aim of this study was to compare the prevalence of apical periodontitis (AP) between postmenopausal women diagnosed with osteoporosis (OP) and systemically healthy postmenopausal women, representing a Mediterranean subpopulation.
Methods: The study included 71 postmenopausal women aged between 50 and 70 years. Based on dual-energy X-ray absorptiometry (DEXA) results, participants were classified into two groups: osteoporotic and healthy. Panoramic radiographs of each subject were evaluated for the presence of AP and scored using the periapical index (PAI). Additionally, the decayed, missing, and filled teeth (DMFT) index, the number of root canal-treated (RCT) teeth, and smoking status were recorded. Statistical analysis was performed using the independent samples t-test, Mann–Whitney U test, and Chi-square tests (p<0.05). Interobserver agreement was found to be high (κ=0.86).
Results: No statistically significant differences were observed between osteoporotic and systemically healthy postmenopausal women in terms of AP prevalence, PAI scores, DMFT index, or the number of RCT teeth (p>0.05).
Conclusion: The findings suggest that OP may not be an independent risk factor for the development of apical inflammation in postmenopausal women. From a clinical perspective, pharmacologically managed OP does not appear to negatively affect endodontic prognosis. Further comprehensive, multicenter studies are warranted to better understand the impact of systemic bone diseases on periapical inflammation.

Purpose: This study aimed to evaluate patient satisfaction following root canal treatment performed by undergraduate and postgraduate dental students.
Methods: A total of 120 patients were included (n=60 per group). A validated questionnaire was used, consisting of socio-demographic questions and eight satisfaction items scored on a 5-point Likert scale. Statistical analyses were performed using non-parametric tests, with significance set at p<0.05.
Results: No significant differences were found between the groups regarding socio-demographic variables (p>0.05). However, overall satisfaction scores were significantly higher among patients treated by postgraduate students (p=0.001). In the undergraduate group, differences were observed according to age and marital status, with some results only marginally significant (p≈0.04). Patients with lower income reported greater satisfaction with treatment plan explanations (p=0.027).
Conclusion: Both groups received generally favorable satisfaction ratings; however, postgraduate students obtained significantly higher scores. In the undergraduate group, socio-demographic factors, particularly age and marital status, appeared to influence satisfaction levels. Overall, these findings suggest potential areas for improvement in dental education and clinical supervision, including strategies to enhance patient-centered care.

Purpose: The increasing development and clinical adoption of nickel-titanium (NiTi) rotary systems in Türkiye highlights the need for performance comparisons with widely used reference instruments. This study aimed to evaluate the shaping ability of locally manufactured files (EndoPlus Universal Gold-EPUG and EndoArt Action Gold-EAG vs. ProTaper Gold-PTG) in terms of canal transportation, weight loss, and changes in prepared canal area using standardized resin blocks with 30° curvature and 16 mm length.
Methods: Twenty-four blocks with known initial weights were photographed under a stereomicro-scope at 4× magnification, randomly divided into three groups, and prepared with rotary files up to size F2 following each system’s sequence. Irrigation with 2 mL saline was performed after each instrument. Post-instrumentation weights were recorded using a precision balance, while canal transportation at apical, middle, and coronal levels and canal area changes were calculated by superimposing pre- and post-instrumentation images with ImageJ software. Data were analyzed using one-way and two-way ANOVA with Bonferroni post-hoc testing at a 0.05 significance level.
Results: Instrument fractures occurred in one sample from PTG (S2), four from EPUG (three S2, one S1), and two from EAG (S2). No statistically significant differences were found among the groups regarding canal transportation and shaped area changes (p=0.43 and 0.06, respectively). The greatest transportation was observed coronally in all groups (p=0.001). Coronal transportation was significantly higher than apical transportation in the PTG and EAG systems (p=0.001 and p=0.048, respectively). Weight loss was significantly different among all groups (PTG: 3.16±0.45 mg; EPUG: 4.63±0.26 mg; EAG: 5.90±0.63 mg; p=0.001).
Conclusion: Within the limitations of this study, the shaping performance of locally manufactured systems appeared comparable, though further research in extracted human teeth is recommended.

Purpose: This study assessed the efficacy of various irrigation solutions (EDTA, EDTA with benzalkonium chloride [BAC], ethanol, and glycolic acid) and techniques (conventional needle irrigation, sonic, and ultrasonic systems) for removing calcium hydroxide Ca(OH)2 and double antibiotic paste (DAP) medicaments.
Methods: Ca(OH)2 and double DAP were placed in the canals of extracted single rooted human mandibular premolars. The specimens were divided into groups based on the irrigation solutions and techniques (conventional needle irrigation, sonic and ultrasonic activation) used. After removal of the medicaments, residues were evaluated using stereomicroscope. The Mann-Whitney U, the Kruskal-Wallis and by Dunn-Bonferroni post hoc tests were used to analyze the data.the study results at a 95% confidence level.
Results: The lowest residue scores were observed with 17% EDTA and 17% EDTA with BAC, regardless of irrigation techniques for Ca(OH)2, and with 17% EDTA, 17% EDTA with BAC, and ethanol for DAP (p<0.05). The highest scores were obtained with 10% glycolic acid. The methods of irrigation showed similar effectiveness in each solution group.
Conclusion: EDTA and EDTA + BAC solutions provided the lowest residue scores, confirming EDTA’s effectiveness regardless of the irrigation method. While BAC or ethanol may enhance intracanal medication removal, glycolic acid likely caused precipitation, leading to higher scores.

Purpose: This study investigated the effect of different nickel–titanium file systems and irrigation protocols on the accuracy of working length measurements during root canal preparation.
Methods: A total of 72 extracted mandibular central incisors were decoronated at 18 mm. Actual lengths (AL) were determined using a hand file and digital caliper under a microscope. Teeth were divided into four main groups based on irrigation solution, and then into two subgroups by file system: 2.5% or 5% NaOCl with/without 9% HEDP, combined with either WaveOne Gold(WOG) or WaveOne(WO). Root canals were shaped using WOG or WO files with a VDW Gold Reciproc motor in an alginate model simulating the oral environment, following the respective irrigation protocol. Electronic lengths (EL) were determined using an integrated electronic apex locator. EL–AL differences were calculated and analyzed using Kruskal-Wallis and Mann-Whitney U tests (p<0.05).
Results: No significant differences in EL–AL values were observed among the main irrigation solution groups or between files with different heat treatments (p>0.05). All tested conditions showed clinically acceptable accuracy.
Conclusion: These findings suggest that the type of file system and irrigation solution, including continuous chelation, do not compromise the reliability of EL determination during endodontic treatment.

Purpose: This laboratory study aimed to evaluate age-related differences in root canal curvature of human mandibular first molars using high-resolution micro-computed tomography (micro-CT).
Methods: Mesial roots of extracted human mandibular first molars (n=93) were collected and classified into three age groups: ≤30 Years, 31−59 years, and ≥60 years. The root canal curvature was evaluated in both the mesiodistal and buccolingual planes using micro-CT reconstructions analyzed in AutoCAD according to Pruett’s method.
Results: Curvature values were consistently greater in the buccolingual than in the mesiodistal plane across all age groups. Mesiobuccal and mesiolingual canals exhibited similar patterns, and no significant differences were observed among the age groups (p>0.05).
Conclusion: Mandibular first molars exhibited consistent canal curvature across age groups. Although age did not significantly affect this parameter, careful preparation and appropriate instrument selection remain essential for mesial canals in all patients.

Purpose: The present study aimed to compare and evaluate the extent of structural loss during selective endodontic retreatment of mandibular incisors using conventional burs versus customized retreatment burs.
Methods: Twenty-six extracted mandibular anterior teeth exhibiting two canals, confirmed through intraoral periapical radiographs in the mesiodistal dimension, were selected for the study. Access cavity preparation was selectively performed for buccal canal and lingual canal was intentionally missed. Bio-mechanical instrumentation and obturation was completed for buccal canal following copious irrigation with 5.25% sodium hypochlorite, 0.9% saline, and 17% EDTA. The lingual canals were intentionally left untreated. Access cavity was restored using composite resin. Preoperative cone-beam computed tomography (CBCT) scans were acquired for all samples. The specimens were then randomly allocated into two groups:
• Group A: Selective retreatment performed using a customized long-shank parallel round bur guided by a static 3D-printed template to locate the missed lingual canal.
• Group B: Selective retreatment carried out using a conventional small round bur (#1) under 10× magnification.
Following the retreatment procedures, postoperative CBCT scans were obtained. Volumetric substance loss was calculated using image analysis software by comparing pre- and postoperative scans.
Results: Group A exhibited significantly lower volumetric structural loss than Group B. The use of a customized guided bur enabled precise localization of the untreated canal with minimal removal of dentinal tissue.
Conclusion: Selective endodontic retreatment of mandibular anterior teeth with two canals, when performed using a guided endodontic approach with a customized bur, results in significantly reduced structural loss compared to the conventional technique. This method enhances accuracy and preserves tooth structure, offering a clinical advantage in retreatment cases.

Purpose: The aim of this study was to investigate the effects of preheating on the degree of conversion (DC), flexural strength (FS) and flexural modulus (FM) of bulk-fill resin composites with varying viscosities and filler contents.
Methods: Four bulk-fill resin composites - EverX Posterior (EXP), EverX Flow Bulk (EXF), Filtek One Bulk Fill (ONE), SDR Plus Flow (SDR) - and a conventional composite - Filtek Z250 (Z250) - as a control group were evaluated. Each composite was divided into three subgroups: [1] Room temperature (20±1°C), [2] preheated to 39°C, and [3] preheated to 55°C. DC, FS and FM results of the specimens were evaluated. Statistical analysis included one-way ANOVA and post hoc Tukey tests (p<0.05).
Results: At room temperature, Z250 exhibited the lowest DC (41.32%), significantly lower than EXP (52.11%) and other bulk fill composites. FS values for Z250 (145.68 MPa), EXF (152.19 MPa) and EXP (157.24 MPa) at room temperature were comparable but higher than for ONE (100.70 MPa) and SDR (114.95 MPa). Preheating increased the DC and FS of Z250 and EXP but not of EXF, ONE or SDR.
Conclusion: Preheating is recommended to enhance the properties of viscous, fiber-reinforced (EXP) and conventional hybrid (Z250) composites for stress-bearing restorations. In contrast, it offers no significant mechanical advantage for the flowable bulk-fill composites tested (EXF, SDR, ONE), underscoring that the benefit of preheating is highly material-dependent.

Purpose: The aim of this study was to compare the effectiveness of different root canal filling solvents in removing filling material with AH Plus or MTA-Fillapex from premolar teeth with artificially created lateral canals.
Methods: One hundred twenty extracted single-rooted premolar teeth with standardized artificial lateral canals were prepared and obturated using AH Plus or MTA-Fillapex with a warm vertical compaction technique. Retreatment was performed using ProTaper Universal Retreatment instruments with four different conditions: No solvent (control), chloroform, endosolv, and eucalyptol solvent. Residual filling material in the main canals was evaluated under a stereomicroscope using pixel-based image analysis, while residual filling material in the lateral canals was assessed radiographically. Main canal data were analyzed using two-way ANOVA and post-hoc tests, whereas lateral canal data were reported descriptively.
Results: The type of sealer did not significantly affect the amount of residual filling material in the main canal. In contrast, the solvent type had a significant effect. Endosolv resulted in significantly less residual filling material compared with chloroform, eucaliptol, and the control group. In the lateral canals, no method provided measurable and consistent removal, and therefore only descriptive analysis was performed.
Conclusion: Endosolv was the most effective solvent for removing root canal filling materials from the main canal. However, the anatomical complexity of lateral canals limits the effectiveness of all retreatment procedures.

Purpose: The aim of this study was to examine the quality and reliability of Turkish videos shared on the YouTube video sharing site regarding root canal treatment.
Methods: A total of 360 videos were listed using three different keywords, and 99 of these were included in this study. The quality and reliability of the videos were assessed using the Quality Criteria for Consumer Health (DISCERN) and the Global Quality Scale (GQS).
Results: Quality assessment results demonstrated that the mean DISCERN score was 27.95±6.93, and the mean GQS score was 1.83±0.77. According to the DISCERN scores, the quality and reliability of the videos were mostly ‘inadequate,’ while the GQS score categorized the average video quality as ‘poor.’ A positive correlation was found between DISCERN and GQS scores (p<0.001; r=0.917).
Conclusion: There is a growing need for high-quality video content that delivers comprehensive and accurate information regarding the indications, clinical procedures, and postoperative prognosis of root canal treatment, ideally developed by endodontic specialists. After assessing the quality of these videos using internationally accepted criteria, it is believed that sharing only high-quality videos will provide more informative content for patients.

Purpose: This study evaluated the effect of different minimally invasive access cavity designs on the discoloration of maxillary and mandibular first molars using spectrophotometric analysis.
Methods: Eighty first molars (maxillary n=40; mandibular n=40), free of caries and restorations, were randomly allocated—stratified by arch—to eight groups (n=10 per group) according to access cavity design (traditional, conservative, ultraconservative, truss; four groups per arch). Using a dental operating microscope, access cavities were prepared, working lengths determined, and canals instrumented with Reciproc R25. Irrigation activation was performed with a #20 Irrisafe ultrasonic tip, followed by single-cone obturation with R25 gutta-percha and A2 composite restorations. Color measurements were recorded using a Vita Easyshade V spectrophotometer at baseline, immediately after treatment, and at 1, 7, 30, and 60 d. L*a*b values were converted to Commission International de I’Eclairage (CIELAB) ΔE values. Data were analyzed with appropriate statistical tests.
Results: Clinically perceptible discoloration (ΔE≥3.3) was observed in all groups at various time points. In the maxillary molars, traditional access cavities showed significantly greater discoloration at one month compared at baseline (p<0.05). No significant differences were found among the other groups (p>0.05).
Conclusion: Traditional access cavities in maxillary molars produced greater discoloration than minimally invasive access cavities. Minimally invasive access cavity designs may help maintain tooth color by preserving dentin and reducing restorative material volume.

Purpose: To evaluate the torsional fatigue resistance of One Curve Mini (OCM), HyFlex EDM (HEDM), WaveOne Gold Primary (WOG), and Reciproc Blue R25 (RPB) rotary and reciprocating nickel-titanium (NiTi) single-file systems.
Methods: Eighty NiTi instruments were tested: OCM (25/.06), HEDM (25/.08), WOG (25/.07), and RPB (25/.08) (n=20 per group). The instruments were fixed at apical 3 mm along their long axis and constant rotation of 2 rpm were applied until fracture occured. Ultimate strength at maximum torque and distortional angle for each file were measured using torsiometer. Statistical analysis was performed with one-way analysis of variance followed by Tukey’s post-hoc test, using a 5% significance level (p<0.05). All the fractured instruments were scanned using scanning electron microscope to confirm that the instruments were fractured due to torsional fatigue.
Results: Maximum torque values were observed in HEDM and RPB (p<0.05) and the minimum values were in OCM (p<0.05) files. The torque values of WOG were not statistically different from the other three files (p>0.05). The distortion angle was highest in OCM and HEDM and the lowest values were in WOG files (p<0.05). RPB files have a similar distortion angle with the other three files (p>0.05).
Conclusion: HEDM and RPB were highest and OCM was the least resistant to torsional stress among the tested NiTi file systems.

In this case report, the treatment procedure and follow-up of a left maxillary central incisor that previously underwent a regenerative endodontic procedure is presented. After a thorough anamnesis, clinical and radiographical examination, a non-surgical endodontic retreatment was applied. Apexification treatment included intensive irrigation, Ca(OH)2 administration and finally, creating an apical plug with MTA. Follow-up radiographic and clinical examination showed healing of the periapical area and reduction of initial symptoms, keeping the tooth in function. As regenerative endodontic procedures can be recognized as the best option for permanent teeth with immature apices, there are always alternatives that can be implemented following failure.