International endodontic journal最新文献

Aim: To describe an unusual case of post-traumatic trigeminal neuropathy affecting an accessory canal of the canalis sinuosus related to a maxillary central incisor.

Summary: This case report presents a 48-year-old female patient who suffered from neuropathic pain following the crown placement and endodontic treatment of a left maxillary central incisor (tooth 21). A cone beam computed tomographic (CBCT) scan of the anterior maxilla revealed an accessory canal apical to tooth 21, with extruded sealer within the bony channel. A sustained resolution of the patient's symptoms was achieved following apicectomy of the tooth and surgical resection of the accessory canal. The tooth remained asymptomatic at the 5-year follow-up.

Aim: Despite significant advances in dental pulp stem cell (DPSC)-based regeneration of the pulp-dentine complex, regulating the directed differentiation of these cells remains a key challenge. The present study investigated the role and underlying mechanism of the KDM4D-RPS5 complex in modulating the odontogenic differentiation of DPSCs, with the goal of providing insights to inform strategies for tooth tissue regeneration and repair.

Methodology: To assess the osteo/dentinogenic differentiation capacity of DPSCs, multiple techniques were employed, including alkaline phosphatase (ALP) activity assays, Alizarin Red S staining, quantitative calcium analysis, and detection of osteo/dentinogenic marker expression. Gene expression levels were quantified using quantitative real-time polymerase chain reaction and Western blot. Chromatin immunoprecipitation and co-immunoprecipitation (Co-IP) assays were performed to investigate the underlying molecular mechanisms. Mitochondrial morphology in DPSCs was observed via transmission electron microscopy (TEM), while the oxygen consumption rate was measured using a Seahorse XF Analyser, and mitochondrial membrane potential was assessed with a JC-10 assay. Finally, the in vivo efficacy of odontogenic differentiation was validated through a subcutaneous transplantation assay in nude mice.

Results: We first demonstrated that KDM4D significantly promoted the osteo/dentinogenic differentiation of DPSCs. Furthermore, KDM4D bound directly to RPS5 via a specific structural domain to form a functional complex; disruption of this binding site abolished its capacity to drive differentiation. Mechanistically, ChIP assays revealed that the KDM4D-RPS5 complex epigenetically activated the downstream gene CNR1 by demethylating H3K9me2 at its promoter, thereby facilitating DPSC differentiation. Additionally, mitochondrial functional analysis showed that overexpression of KDM4D, RPS5, or CNR1 enhanced mitochondrial membrane potential and augmented energy metabolism, further supporting the differentiation process.

Conclusions: KDM4D bound to RPS5 to form a protein complex, which regulated the demethylation of CNR1 H3K9me2 and further influenced the osteo/dentinogenic differentiation of DPSCs by promoting mitochondrial energy metabolism. These findings identify the KDM4D-RPS5-CNR1 axis as a promising therapeutic target for enhancing DPSC-based dental tissue regeneration.

Introduction: This feasibility study presents the diagnostic accuracy of a novel dental-dedicated magnetic resonance imaging (ddMRI) system for assessing pulp vitality and diagnosing apical periodontitis (AP), as an adjunct to clinical assessment and cone beam CT (CBCT) imaging.

Methods: Ten consecutive patients with possible endodontic problems were screened, and ultimately 18 teeth in nine patients (10 healthy teeth, five necrotic teeth with suspected AP and three necrotic or root canal treated teeth with no suspicion of AP) with a recent CBCT were included. The teeth were tested for vitality and clinical signs of AP. The CBCT volumes were assessed by three trained observers for signs of AP. The teeth were scanned using the Magnetom Free.Max Dental Edition ddMRI system (Siemens Healthineers, Forchheim, Germany), operating at 0.55 T with a seven-channel dental-dedicated surface coil. Six pulse sequences optimised for periapical diagnostics were applied, with a total scanning time of approximately 18 min per tooth. Images were assessed by three trained observers for anatomical structure conspicuity (root tip, periapical bone and lamina dura), pulp vitality determined by presence of signal and presence of AP determined by accumulation of fluid in the periapical area. The assessed pulp vitality status and presence of AP on ddMRI were compared to the clinical and radiological findings. Inter-modality agreement was calculated using kappa statistics, and diagnostic accuracy was evaluated with consensus between clinical findings and CBCT imaging as the reference standard.

Results: All anatomical structures were visible in all cases. ddMRI showed high diagnostic accuracy. For pulp vitality, the inter-modality agreement kappa was 0.77 and accuracy was 0.88. For AP, the inter-modality agreement kappa was 0.87 and accuracy was 0.94.

Conclusions: ddMRI show promising results as a non-ionising imaging modality for assessment of pulp vitality and diagnosis of AP. This feasibility study demonstrates the potential of ddMRI to provide accurate diagnostic support, laying a foundation for larger-scale validation studies and clinical applications.

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.