International endodontic journal最新文献

Aim: Pulpitis represents a prevalent clinical condition in dentistry. Macrophages play pivotal roles in pulpitis immunopathology, while dental pulp stem cells (DPSCs) serve as key effectors in pulp tissue repair and immune regulation. Although mesenchymal stem cells are known to regulate immunity through mitochondrial transfer, this mechanism remains unexplored in pulpitis. This study investigated how mitochondrial transfer influences pulpitis progression and resolution.

Methodology: To investigate DPSC-macrophage mitochondrial transfer and its role in polarisation of macrophages, Lipopolysaccharide-stimulated cocultures were established. Transfer dynamics were analysed by fluorescence microscopy and flow cytometry. Macrophage polarisation (assessed via quantitative real-time polymerase chain reaction (qRT-PCR)/flow cytometry) in the cocultures was detected after mitochondrial transfer agonist/inhibitor treatment. Macrophage polarisation (assessed via qRT-PCR/flow cytometry) and mitochondrial function (reactive oxygen species production, membrane potential) were compared between mitochondria-receiving (Mito⁺) and non-receiving (Mito^-) macrophages. Immunometabolic profiles (itaconate/succinate) were evaluated by qRT-PCR/immunofluorescence. Human dental pulp explants and experimental rat pulpitis models demonstrated the anti-inflammatory and reparative effects of mitochondrial transfer agonists. Data were analysed by one-way ANOVA and unpaired t-tests (α = 0.05).

Results: Mitochondrial transfer from DPSCs to macrophages reduced during inflammation. Pharmacological inhibition of mitochondrial transfer exacerbated M1 macrophage polarisation, whereas its enhancement promoted M2 polarisation. Mito⁺ macrophages exhibited stronger M2 polarisation, improved mitochondrial function, and reduced itaconate/succinate metabolism compared to Mito^- cells. Notably, using the inflamed dental pulp explant and the experimental rat pulpitis model, we demonstrated that augmenting mitochondrial transfer can effectively alleviate pulpitis and promote repair.

Conclusions: Mitochondrial transfer from dental pulp stem cells to macrophages via tunnelling nanotubes improved macrophage metabolic profiles. Enhanced mitochondrial transfer promoted M2 macrophage polarisation, thereby alleviating pulpal inflammation and promoting repair.

Aim: To evaluate the shaping ability, debris removal efficiency and morphological alterations induced by the SAF Infinitum system during progressive instrumentation of flat-shaped root canals of mandibular incisors.

Methodology: Twelve extracted mandibular incisors with flat-shaped canals were selected using micro-CT and instrumented with 1.5-mm Self-Adjusting File (SAF) Infinitum instruments under continuous NaOCl-HEDP irrigation for 2, 4 and 6 min. Micro-CT scans were performed before and after each step to evaluate changes in canal volume, surface area, debris removal, unprepared canal walls and dentine thickness. Following the preparation procedures, all instruments were examined under a microscope for defects. Data were analysed using GLM for repeated measures and the Related-Samples Friedman test (α = 0.05).

Results: Root canal preparation with the SAF Infinitum significantly increased canal volume and surface area (p = 0.000), while progressively reducing unprepared canal wall areas and hard tissue debris (p = 0.000). Unprepared surfaces decreased by 77.8% and debris volume by 77.2% from 2 to 6 min, with improved cleaning efficiency over time. Dentine thickness also declined significantly (p < 0.001), particularly on the lingual surface at the pericervical area and the mesial surface at midroot. Buccolingual walls consistently remained above 1.0 mm, whereas only two mesiodistal cross-sections at the midroot level exhibited dentine thickness below 0.5 mm. After 6 min, all instruments showed structural deformations, and one specimen exhibited a minor intracanal fragment.

Conclusions: This is the first study to evaluate the progressive, time-dependent effects of the SAF Infinitum system in challenging flat-shaped root canals. The system exhibited a time-dependent shaping effect, with most morphological changes occurring within the first 2 min, followed by continued, although more gradual, improvements up to 6 min. Cleaning efficacy increased steadily over time, while remaining dentine thickness generally stayed above critical safety thresholds. All instruments showed structural deformations after 6-min preparation.

Objective: Photon-counting computed tomography (PCCT) represents a major innovation in X-ray detection technology, offering improved signal efficiency and reduced electronic noise compared with cone-beam computed tomography (CBCT), which can enhance image quality. This study aimed to evaluate the diagnostic performance of PCCT in detecting vertical root fractures (VRF), in comparison with four CBCT devices.

Methodology: Eighteen single-rooted teeth were endodontically treated, and VRF was induced in eight of them. Each tooth was individually placed into the mandibular first premolar empty socket of an anthropomorphic phantom and scanned under three conditions: without a metal post, with a nickel-chromium metal post (Ni-Cr), and with a cobalt-chromium metal post (Co-Cr) in five CT devices: the NAEOTOM Alpha PCCT (Siemens Healthineers) device and four CBCT devices (3D Accuitomo 170-Morita, Veraview X800-Morita, NewTom VGi evo-NewTom, and Carestream 9600-Carestream). The highest-resolution protocol available on each device was used, resulting in a total of 270 scans. Five experienced dentomaxillofacial radiologists independently and blindly evaluated the scans using a five-point confidence scale. Diagnostic accuracy was assessed by calculating the area under the ROC curve (AUC), sensitivity, and specificity, with results compared by two-way ANOVA with post hoc Tukey's test (α = 0.05).

Results: NewTom VGi and PCCT devices showed significantly higher AUC values than the Veraview X800, regardless of the metal post material (p < 0.05). CS9600 and PCCT devices exhibited significantly higher sensitivity values in diagnosing with Ni-Cr posts than the Accuitomo 3D and Veraview X800 devices (p < 0.05). With the Co-Cr metal post, the NewTom VGi, CS9600, and PCCT devices showed significantly higher sensitivity values compared to the Veraview X800 device (p < 0.05). There were no statistically significant differences in specificity, regardless of the CT device or metal post material (p > 0.05).

Conclusions: The NEAOTOM Alpha PCCT showed high diagnostic accuracy for VRF detection in an ex vivo model, comparable to high-resolution CBCT devices, highlighting its diagnostic performance under controlled ex vivo conditions.

Introduction: Cone-beam computed tomography (CBCT) has become an integral part of endodontic diagnosis and treatment, with voxel size being a critical parameter affecting spatial resolution and diagnostic outcomes. This systematic review and meta-analysis examined the effect of voxel size on the diagnostic outcome of CBCT images for root canal anatomy assessment.

Methods: A search was conducted in PubMed, Web of Science, Embase, and Scopus databases without date restrictions. Studies comparing different CBCT voxel sizes for root canal anatomy evaluation using quantitative diagnostic outcomes were included. Two reviewers independently performed study selection, data extraction, and quality assessment using QUADAS-2. Meta-analysis was conducted using random-effects models with subgroup analysis by voxel size categories (≤ 125 μm and > 125 μm).

Results: Fifteen studies met the inclusion criteria, evaluating voxel sizes from 75 to 400 μm across various anatomical structures. Seven studies were included in the meta-analysis. Individual studies consistently demonstrated improved visualisation with smaller voxel sizes, particularly for larger structures such as second mesiobuccal canals in maxillary molars. Overall pooled diagnostic accuracy was 80% (95% CI: 75%-84%) with substantial heterogeneity (I² = 86.74%). Subgroup analysis showed diagnostic accuracy of 75% (95% CI: 68%-82%) for voxel sizes > 125 μm and 85% (95% CI: 80%-90%) for voxel sizes ≤ 125 μm. The difference between the two groups was statistically significant (p = 0.002). Moreover, meta-regression showed a statistically significant association between voxel size and diagnostic accuracy (p = 0.0086).

Conclusions: The current study's findings suggest that there is an association between reducing the voxel size and enhancing the diagnostic outcome of CBCT images in assessing root canal anatomy. Although the meta-regression showed a statistically significant correlation, the results should be interpreted cautiously because of methodological heterogeneity, the complex interplay of imaging parameters beyond voxel size alone, and the lack of clinical studies. Future research should focus on standardised clinical studies to examine the impact of voxel size on the diagnostic outcome of CBCT images.

Aims: To evaluate the cleaning efficacy and biological effects of ultrasonic (US)-activated sodium hypochlorite (NaOCl) for root surface decontamination and decellularisation in delayed tooth replantation.

Methodology: Cementum discs prepared from extracted healthy single-rooted teeth were treated with varying NaOCl concentrations (1%-5.25%), with or without US activation. Necrotic periodontal ligament (PDL) tissue clearance, cementum integrity and elemental composition were inspected by scanning electron microscopy and energy dispersive X-ray spectroscopy. Biocompatibility of the treated cementum discs with human periodontal ligament cells (PDLCs) and rat bone marrow mesenchymal stem cells was assessed, alongside osteogenic differentiation, inflammatory cytokine expression, collagen type I (COL-I) and receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) signalling. A Sprague-Dawley rat maxillary incisor delayed replantation model was established to assess in vivo healing outcomes of US-activated NaOCl, evaluated by micro-computed tomography, haematoxylin and eosin staining and Masson's trichrome staining and tartrate-resistant acid phosphatase (TRAP) histochemistry.

Results: Increasing NaOCl concentration accelerated removal of necrotic PDL. US activation significantly shortened NaOCl treatment time (p < 0.05) and allowed effective necrotic PDL removal at 1% NaOCl without damaging cementum. Treated cementum surfaces showed higher calcium/phosphorus and lower carbon/nitrogen contents (p < 0.01). US-assisted 1% NaOCl enhanced cell adhesion, osteogenic differentiation and COL-I expression while reducing interleukin-6, tumour necrosis factor-α and the RANKL/OPG ratio. In vivo, NaOCl combined with US activation significantly reduced root resorption volume (p < 0.05), preserved periodontal architecture, and decreased TRAP-positive osteoclast counts compared with saline or untreated controls.

Conclusions: US-activated 1% NaOCl achieves rapid, selective removal of necrotic periodontal tissue while preserving cementum and producing a decellularised surface. This strategy attenuates inflammatory responses, suppresses osteoclastogenesis, mitigates inflammatory root resorption and may extend the therapeutic window for delayed tooth replantation.

Aim: This study aimed to detect the root number of maxillary premolars on panoramic radiographs using deep learning models.

Methodology: This retrospective study included 925 maxillary premolars from 350 patients with panoramic radiographs and CBCT scans, which served as the reference standard to determine root numbers. Panoramic images were cropped to isolate the premolar root region, preprocessed, resized, and used to train three convolutional neural network (CNN) models (AlexNet, DenseNet-121, EfficientNet-B0) equipped via transfer learning. Data augmentation was applied to address class imbalance. Five-fold cross-validation was performed, with each fold allocating 86% of the data (n = 797) for training, 7% (n = 64) for validation and 7% (n = 64) for testing, without patient-level overlap. An independent external validation set was also constructed to assess generalizability. An experienced endodontist evaluated the same external validation set for comparison. Accuracy, sensitivity, specificity, F1-score, and the area under the ROC curve (AUC) were calculated as mean ± standard deviation (SD) with 95% confidence intervals (CI). The ensemble model was used to improve robustness. Paired DeLong tests were performed to compare AUCs for both cross-validation predictions (n = 322) and external validation predictions (n = 148).

Results: In cross-validation, the ensemble achieved the strongest performance (accuracy 0.90, F1-score 0.90, sensitivity 0.89, specificity 0.91, AUC 0.94). Among individual models, EfficientNet-B0 and AlexNet performed similarly (accuracy 0.85), while DenseNet-121 performed lower (0.81). DeLong analyses confirmed significantly higher AUCs for the ensemble compared with all individual models (p < 0.05). On the external validation set, the ensemble again performed best (accuracy 0.87), followed by AlexNet (0.85), EfficientNet-B0 (0.84) and DenseNet-121 (0.84). The expert clinician achieved an accuracy of 0.82. DeLong comparisons on external validation predictions revealed no significant AUC differences among models (all p > 0.05), except for AlexNet vs. the ensemble. Confidence interval plots confirmed the ensemble's reduced variability and narrowest CIs.

Conclusions: Deep learning models showed reliable performance in predicting root numbers of maxillary premolars from panoramic radiographs, with the ensemble model achieving the most stable and accurate results. These findings indicate that deep learning systems may serve as a supportive tool in clinical decision-making.

Introduction: Diagnosing cemental tears remains challenging, and treatment outcomes can be unpredictable; recommendations for their diagnosis and management are primarily based on case reports and anecdotal experience. Although a classification has been developed for cemental tears, its clinical applicability and importance have yet to be investigated and validated.

Aims and objectives: This study aims to deepen our understanding of cemental tears through a comprehensive examination of a patient cohort, focusing on: (i) evaluating the cases based on the classification for cemental tears; (ii) assessing clinical presentations, radiographic features, and histopathological characteristics; and (iii) identifying factors that influence diagnosis, treatment approaches, and clinical outcomes.

Materials and methods: This retrospective cohort study evaluated teeth diagnosed with cemental tears at the university's endodontic clinic from September 2019 to June 2024. The review included case histories, clinical, radiographic and histopathological findings, as well as the treatments performed and their outcomes. Descriptive statistics were used.

Results: Thirty-seven patients with 45 teeth diagnosed with cemental tears were included. Majority of affected teeth (68.9%) had received previous treatment or undergone previously initiated therapy. Among those root treated, most (84.6%) exhibited adequate obturation. Pain, swelling and/or sinus tracts, as well as significant crestal bone loss, were detected in approximately half of the cases. Cone-beam computed tomography (CBCT) scans and direct inspection successfully identified all affected teeth, whereas periapical radiographs (PR) only detected 60.0%. Histopathological analysis revealed cementum in all 37 cases comprising 45 teeth, bone in 11 cases, and cystic lesions in 5 cases. Unfavourable treatment outcomes were observed in 78.9% of teeth classified as Class 4-6. Across all classes, regenerative approaches using enamel matrix derivatives (EMD) achieved favourable outcomes in 44.4% of teeth treated, xenografts in 38.1%, and collagen membranes in 55.6%. Notably, none of the teeth in Classes 4-6 treated with EMD or xenografts demonstrated favourable outcomes.

Conclusion: CBCT scans, direct inspection, and histopathological examination demonstrated a higher detection rate compared to PR. Classification is a critical prognostic factor, with Classes 4-6 exhibiting poorer outcomes than others. The impacts of regenerative approaches on periradicular healing appear questionable.

Aim: This study aimed to evaluate the dental pulp response to different 38% silver diamine fluoride (SDF) products in Wistar rats with deep cavities.

Methods: Sixty-four maxillary first molars from Wistar rats were randomly assigned to eight groups (n = 8 per group) for 7-28 days treatments: Group 1- a locally produced 38% SDF (T-SDF), Group 2-Saforide (Toyo Seiyaku Kasei Co. Ltd., Japan), Group 3-Topamine (Dentalife Australia Pty. Ltd., Thailand), and Group 4-deionised water (DI) as control. After a deep cavity preparation, treatments were applied. Rats were euthanized at days 7 and 28 post-treatment, and molars were subjected to histopathological examination to evaluate inflammation, soft tissue organisation, reactionary dentine formation and silver penetration depth. Data were analysed using the Kruskal-Wallis; penetration depth was analysed using one-way ANOVA (p < 0.05).

Results: At day 7, all groups showed no to mild inflammation beneath the axial wall, with no significant differences in inflammation scores (p > 0.05). Normal odontoblastic organisation was observed in the T-SDF and Saforide groups. Partial loss of soft tissue organisation occurred in 28.57% of the Topamine group and 16.66% of the DI group, though central pulp remained normal. Mean soft tissue organisation scores were 1.29 ± 0.488 for Topamine and 1.17 ± 0.408 for DI (p = 0.203). Reactionary dentine formation was noted across most teeth, with no significant differences among groups (p = 0.548). By day 28, no significant differences in inflammation or soft tissue organisation were observed (p > 0.05). Reactionary dentine formation ranged from none to over four times the predentine thickness, with no significant group differences (p = 0.932). The remaining dentine thickness of prepared cavities ranged from 71.70-594.76 μm. Silver precipitation was observed in all SDF-treated specimens, absent in controls. Silver penetration into dentinal tubules toward the pulp showed no statistically significant differences among groups at both days 7 and 28 (p = 0.741 and 0.607, respectively).

Conclusion: When applied in deep cavities, SDF products elicited a dental pulp response comparable to that of the control, indicating their biocompatibility and safety for use in deep dentine carious lesions.

Aim: To investigate how the application of dual heat treatment during the manufacturing process influences the mechanical performance (flexibility, cyclic fatigue resistance, torsional strength, bending, buckling and cutting efficiency) of rotary nickel-titanium endodontic instruments.

Methodology: Rainbow One (n = 58) and Rainbow Ultra (n = 58) instruments (size 25/0.06, 25 mm length) were evaluated. Geometric analysis was performed using optical 3D scanning and SEM to assess cutting edges, tip design and surface features. Metallurgical characterisation included EDS for elemental composition and DSC for phase transformation temperatures, with segments obtained from the tip, middle and coronal blade regions. Mechanical testing comprised cyclic fatigue, torsional strength (torque to failure, maximum angle of rotation), bending resistance, buckling strength and cutting efficiency. Standardised testing protocols were applied, including ASTM and ISO guidelines for mechanical assessments. Statistical analyses were conducted using Shapiro-Wilk and Levene tests to assess assumptions, followed by independent Student's t-tests, with significance set at 5%.

Results: Both instruments shared equivalent geometries, with deviations below 100 μm, and similar tip designs and surface characteristics. EDS confirmed near-equiatomic NiTi composition for both systems. DSC revealed R-phase crystallographic structure at room temperature for both instruments; however, Rainbow Ultra exhibited higher phase transformation temperatures (Rs 35°C vs. 25°C; Rf 45°C vs. 31°C; As 30°C vs. 24°C; Af 50°C vs. 38°C) and a double austenitic transformation peak, compared with a single peak for Rainbow One. Mechanically, Rainbow Ultra demonstrated greater cyclic fatigue resistance (95.5° ± 7 vs. 79.1 ± 6 s), higher maximum rotation angle (485° ± 49° vs. 402° ± 50°), and improved cutting efficiency (p < 0.05). Rainbow One exhibited higher torque to failure (1.8° ± 0.2 vs. 1.4° ± 0.1 N·cm), greater bending load (369 ± 34 vs. 336 ± 14 gf), and higher buckling resistance (339 ± 32 vs. 273 ± 24 gf), indicating stiffer behaviour.

Conclusions: The application of dual heat treatment during manufacturing significantly influenced the mechanical performance of the tested rotary NiTi instruments. Rainbow Ultra, subjected to sequential heat treatments, exhibited higher flexibility, cyclic fatigue resistance and cutting efficiency, whereas Rainbow One demonstrated greater torsional strength and buckling resistance.