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Background: To investigate the geometric characteristics of the danger zone in the mesial roots of mandibular molars using micro-computed tomography (micro-CT)., Methods: A total of 75 extracted mandibular first (50 were 2-rooted [2RM1] and 25 were 3-rooted [3RM1]) and 35 2-rooted mandibular second molars (2RM2) were collected and evaluated using micro-CT. The morphological aspects of the mesial roots associated with the danger zone (the canal curvature, minimum mesial [MWT] and distal canal wall thickness [DWT], depth and level of root concavities) were evaluated. One-way analysis of variance (ANOVA) was used for multiple group comparisons. Student's t-test or paired t-test was used to test the means between two groups., Results: All mesial roots curved severely (81.8%, 90/110) or moderately (18.2%, 20/110) towards the furcation side, and the mean angle was 25.3 ± 7.2 degrees. The presence of a distolingual root only had limited influence on the geometricgeometry of the mesial root. In the majority of cases, the mean DWT was less than the MWT, and statistical significance (all p < 0.05) was detected at 0-3 mm (MB and ML of 3RM1), 0-4 mm (MB of 2RM1, and MB and ML of 2RM2), 0-5 mm (single mesial canals of mandibular first and second molars), and 0-6 mm (ML of 2RM1) below furcation. The mean depth of distal concavities is always greater (all p < 0.05) than the mesial ones at each root level. Generally, the mean depth of distal concavities increased apically in the cervical portion, reaching the maximum value at 2 mm below furcation, and then declined gradually in the apical portion., Conclusions: The mesial roots of mandibular first and second molars often exhibit severe distal curvature, with a mean Schneider's angle of 25.3 degrees, and the thinnest dentin wall is typically on the distal side. Distal root concavities are significantly deeper than mesial ones, with the maximum depth generally located 2 mm below the furcation. When identifying the danger zone, factors such as DWT should not be considered in isolation. Canal curvature, distal root concavities, and the type of instrument used are also critical in affecting the likelihood and location of strip perforation, though their precise roles warrant further investigations., Competing Interests: Declarations. Ethics approval and consent to participate: The human mandibular first and second molars used in this study were obtained from the Department of Dentistry, Ninth People’s Hospital of Suzhou. All methods have been performed in accordance with the Declaration of Helsinki and have been approved by the Ethics Committee of Ninth People’s Hospital of Suzhou with the approval number # KY2022-089–01. Informed consent was obtained from all subjects and/or their legal guardian(s). Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Aim: To investigate the prevalence of various morphological variations in the roots and canals of lower mandibular molar teeth in the Saudi subpopulation and measure the distance from the root apices to the inferior alveolar canal (IAC)., Materials and Methods: A cross-sectional analysis was conducted on 149 CBCT scans from Taibah University the College of Dentistry (TUCD). Three evaluators independently reviewed scans for anatomical features such as the number of canals, the presence of radix molaris (RM), and root-to-IANC distances. Teeth observed from the medullary cavity to the root apical layers on the coronal, sagittal and cross-section views. Data was analyzed using SPSS 21.0 software. Statistically significant differences were defined at p < 0.05., Results: The prevalence of RM ranged between 0.7%-3.4% in lower first and second molars. The number of the canals in the apex ranged between 2-4 canals, with most molars showing three canals. The prevalence of 2 canals in lower first molars is around 2% and in lower second molars is 9.2%. A significant age-related correlation was noted in distances from the mesial and distal roots to the IAC, with values ranging from 0 to 14.7 mm., Conclusion: The study reveals diverse root and canal morphologies and varying distances to the IANC within the Saudi subpopulation, emphasizing the necessity for precise preoperative radiographic assessments to optimize endodontic outcomes and reduce procedural risks. Findings suggest the need for further research into these anatomical variations to refine diagnostic and treatment strategies in endodontics, particularly in diverse populations to improve patient outcomes., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2025 Aqili et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: To measure the actual moving direction and displacement of the root and crown of maxillary teeth before and after treatment in molar distalization cases using clear aligners(CAs)., Materials and Methods: This retrospective study included 28 adult patients who received maxillary distalization treatment with CAs. The pre- and post-treatment CBCT were superimposed and the crown and root of all maxillary teeth were marked. Achieved and predicted three-dimensional displacement of maxillary teeth were then compared using the paired t test. Mixed-effect model was used to explore the influence of different staging design (one-molar distalization vs. two-molar distalization) and anchorage (TAD vs. Class II elastic vs. no extra anchorage management)., Results: Labial displacement happened to the anterior teeth even the palatal displacement was prescribed. Body distalization of maxillary posterior teeth could not be fully achieved as predicted. The premolars and molars achieved greater distal tipping, buccal inclination, and less distal displacement than predicted. In buccal-palatal dimension, the greatest buccal tipping tendency happened to the 2nd premolar and decreased toward the distal portion of the aligner. In the mesial-distal dimension, the highest accuracy of molar distalization was found in the 2nd molars while the lowest in the 1st premolars. No significant difference was found between two molar distalization patterns. Extra anchorage management devices could not diminish the difference between the predicted and achieved displacement., Conclusions: The achieved molar distalization displacement and anterior teeth retraction is not as good as expected using CAs. The anterior and posterior anchorage loss cannot be completely avoided despite extra anchorage management devices are adopted. The potential reason for the correction of class II malocclusion needs further exploration., Competing Interests: Declarations. Ethics and consent to participate: This study was approved by the Ethics Committee of The Air Force Medical University (IRB-REV-2022101). Written informed consent was obtained from the participant. All methods were performed in accordance with the Declaration of Helsinki. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: Three-dimensional filling of root canals is important for the success of endodontic treatment. The complexity and differences in root canal anatomy in C-shaped canals lead to difficulties in endodontic procedures and make it difficult to compare root canal filling techniques reliably. This study aimed to evaluate the percentage of gap areas of different root canal filling techniques in 3D-printed C2 and C3-shaped root canals using micro-computed tomography (micro-CT)., Methods: Root canals of two human mandibular molars in C2 and C3 configurations were prepared and scanned with micro-CT. Forty replicas (80 in total) were produced from each configuration using a 3-dimensional (3D) printer. C2 and C3 groups were divided into 4 groups according to filling techniques (n = 10); core carrier (CC), cold lateral compaction (CLC), continuous wave obturation (CW) and single cone technique with calcium silicate-based sealer (SC-CSS). Root canals were filled and scanned with micro-CT. The gap areas in the apical, middle and coronal thirds were calculated as percentages. The one-way ANOVA test was used to evaluate the percentages of gap areas and Tukey's test for multiple comparisons., Results: In C2-shaped canals, SC-CSS group showed a statistically higher percentage of gap areas in the apical third (p <.05), there were no significant differences among other groups (p >.05). In the middle part, there were no significant differences among groups (p >.05). The CW group showed a significantly lower percentage of gap areas in the coronal third than other groups (p <.05). In C3-shaped canals, SC-CSS group showed statistically higher percentage of gap areas in apical third (p <.05), CC and SC-CSS groups showed lower percentage areas in the middle part compared to CLC and CW groups (p <.05) and there was no difference between among groups in the coronal third (p >.05)., Conclusions: The SC-CSS technique showed more gap areas in the apical region of C2 and C3-shaped canals. Considering any root canal filling technique in clinical practice, the compaction of filling material in the large volume canals of the C-shaped root canal system is necessary to reduce gap areas., Competing Interests: Declarations. Ethical approval: All procedures performed in the present study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Ethical permission was obtained from the Non-Interventional Research Ethics Committee of the Izmir Katip Çelebi University, Izmir, Turkey (Institutional Review Board #208–09/13/2017). Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

The presence of a supernumerary root is an uncommon dental condition in canine patients, referring to an extra root that forms in a tooth beyond the standard number of roots that are typically expected for that specific tooth. It is a developmental anomaly most commonly observed in large-breed dogs, often as an incidental finding. These supernumerary roots may result from a disruption of the Hertwig's epithelial root sheath, which is responsible for root formation. A 3-year-old Staffordshire terrier presented for a complete oral examination under general anesthesia. The initial intraoral radiographic examination revealed a suspected crown-root fracture of the right mandibular second molar tooth (410). A radiographic examination using the parallel technique, a supernumerary root was identified ruling out the suspected crown-root fracture of 410. The supernumerary root did not require treatment as it was not associated with any pathology or clinical signs. This case report highlights the importance of full-mouth intraoral radiography in the diagnosis of unusual dental conditions, such as supernumerary roots, whose presence may become clinically relevant especially if treatment of a particular tooth becomes necessary. Radiographic technique, positioning and interpretation are essential to avoid misdiagnosis and potential negative consequences for the patient as well as guiding the clinician in making appropriate treatment choices. To the best of the authors' knowledge, the presence of a supernumerary root in a mandibular second molar in a dog has not been previously reported in the veterinary dental literature., Competing Interests: Declarations. Animal ethics: The owner has provided consent for the necessary surgical intervention at the Veterinary Hospital Veterios and for the publication of his pet’s data. No approval of research ethics committees was required. Consent to participate: A written inform consent was signed by the owners of the patients. Consent to publish: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer Nature B.V.)

Objectives: Cone beam computed tomography (CBCT) is an imaging exam used increasingly in various fields of dentistry, and a greater number of endodontists are progressively gaining access to this technology. This study focused on applying an artifact suppression algorithm featured in CBCT software, and designed specifically to address artifacts related to root canal filling materials., Method: The sample consisted of eighty-four mandibular molars, with mesial root canals endodontically treated by using the lateral condensation technique. Four root canal sealers were applied: G1 - Sealapex®, G2 - AH Plus®, G3 - Endofill®, and G4 - Bio-C Sealer. CBCT scans were taken using PreXion 3D Elite®. Initially, the diameter of the root canal filling (in the mesiodistal and buccolingual directions) was measured using a digital micrometer (control). Next, these diameters were reevaluated in the CBCT images using the blooming artifact reduction (BAR) tool of the e-Vol DX software. The Van der Waerden nonparametric analysis of variance was performed, followed by applying the Tukey test to the normalized data. The significance level was set at α = 5%., Results: There were no statistically significant differences (p>0.05) in the measurement of original root canal filling materials obtained by the micrometer versus the e-Vol DX software in the mesiodistal and buccolingual directions., Conclusions: The tested software algorithm effectively suppressed artifacts resulting from obturation materials.

Objectives: Rats are used as animal models for basic and applied research related to orthodontic tooth movement (OTM). The magnitude of mechanical force in OTM rat models mainly depends on the supporting capability of the periodontal ligament (PDL), which is highly associated with the root surface area (RSA). But the size of rat RSA remains unknown, which is the reason why there are still debates on the magnitude of mechanical force in OTM rat models. This study aimed to explore a method for measuring the RSA in rat molars., Design: The maxillary and mandibular samples of rats were scanned by Micro-CT to generate three-dimensional (3D) images, followed by 3D reconstruction of every molar through Mimics Medical 21.0. Geomagic Wrap 2021 and Unigraphics NX 12.0 were utilized to smooth teeth surface and mark the cementoenamel junction (CEJ). Finally, the RSA in rat molars was measured., Results: The results showed that for the six-, eight-, or ten-week-old rats, the average RSA of maxillary first, second, and third molars was 25.90 ± 2.29 mm 2 , 15.92 ± 2.14 mm 2 , and 10.34 ± 1.94 mm 2 . The RSA of mandibular first, second, and third molars was 27.03 ± 2.63 mm 2 , 17.16 ± 1.61 mm 2 , and 11.39 ± 2.13 mm 2 ., Conclusions: Through 3D modelling, we provided data of rat RSA, and observed the trend of increasing RSA mean values with age. These data are pivotal for determining the magnitude of mechanical force required to move rat molars, especially when conducting research related to OTM using rat models., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: Sharing micro-computed tomographic (μCT) scans of teeth increases data accessibility and reduces the need for repeated scans of any given specimen. However, the use of the same TIFF stacks or DICOMs by multiple individuals has the potential to introduce new sources of error. Here, we explore whether use of the same μCT scans by different persons produces comparable results., Materials and Methods: Worn (N = 11) and unworn (N = 4) Cercocebus atys upper molars (UM1 N = 8, UM2 N = 7) were μCT scanned using a Bruker Skyscan 1172 High Resolution Ex Vivo Scanner at a resolution of 22 μm. Two individuals (K.N.G. and M.C.O.) created a 2D mesial slice for each TIFF stack (tooth). Worn teeth were reconstructed by K.N.G. and M.C.O. Three researchers (M.C.O., K.N.G., and J.R.) measured tooth shape, linear enamel thickness, average enamel thickness, and relative enamel thickness (AET and RET). Inter-observer percent error was calculated for each measurement. Univariate ANOVAs were calculated to evaluate variance due to slice maker, reconstructor, tooth, and measurer when percent error averaged > 5%., Results: For unworn teeth, error was generally low and largely due to the person doing the measurement. For worn teeth, wear reconstructor was a statistically significant source of variation for AET and RET., Discussion: We found that (1) inter-observer error was generally low, (2) linear measurements are prone to error, (3) worn teeth did not present an additional source of error as compared to unworn teeth, and (4) different people can use the same μCT scans to reliably reconstruct, slice, and measure teeth., (American Journal of Biological Anthropology© 2025 The Author(s). American Journal of Biological Anthropology published by Wiley Periodicals LLC.)

Background: The severity of furcation involvement (FI) directly affected tooth prognosis and influenced treatment approaches. However, assessing, diagnosing, and treating molars with FI was complicated by anatomical and morphological variations. Cone-beam computed tomography (CBCT) enhanced diagnostic accuracy for detecting FI and measuring furcation defects. Despite its advantages, the high cost and radiation dose associated with CBCT equipment limited its widespread use. The aim of this study was to evaluate the performance of the Vision Transformer (ViT) in comparison with several commonly used traditional deep learning (DL) models for classifying molars with or without FI on panoramic radiographs., Methods: A total of 1,568 tooth images obtained from 506 panoramic radiographs were used to construct the database and evaluate the models. This study developed and assessed a ViT model for classifying FI from panoramic radiographs, and compared its performance with traditional models, including Multi-Layer Perceptron (MLP), Visual Geometry Group (VGG)Net, and GoogLeNet., Results: Among the evaluated models, the ViT model outperformed all others, achieving the highest precision (0.98), recall (0.92), and F1 score (0.95), along with the lowest cross-entropy loss (0.27) and the highest accuracy (92%). ViT also recorded the highest area under the curve (AUC) (98%), outperforming the other models with statistically significant differences (p < 0.05), confirming its enhanced classification capability. The gradient-weighted class activation mapping (Grad-CAM) analysis on the ViT model revealed the key areas of the images that the model focused on during predictions., Conclusion: DL algorithms can automatically classify FI using readily accessible panoramic images. These findings demonstrate that ViT outperforms the tested traditional models, highlighting the potential of transformer-based approaches to significantly advance image classification. This approach is also expected to reduce both the radiation dose and the financial burden on patients while simultaneously improving diagnostic precision., Competing Interests: Declarations. Ethics approval and consent to participate: The study was performed in accordance with the Declaration of Helsinki and approved by the Ethical Review Board at Nanjing University. Ethics committee approval number: NJSH-2022NL-069. All respondents were informed comprehensively and provided written informed consent. For children under the age of 16, the written informed consent was obtained from their parents/ guardians. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: This study aims to investigate the prevalence and morphology of middle mesial canal (MMC) in mandibular first molar (M1M) among a Northwestern Chinese population, and to analyze their relationship with anatomical aspects of the mesial root., Methods: Cone beam computed tomography (CBCT) was utilized to evaluate 898 M1Ms and assess the incidence and morphology of MMC. The following parameters for M1M with or without MMC were obtained: the vertical distance between the first appearance of MMC and canal orifices (D), the distance between mesiobuccal (MB) and mesiolingual (ML) canals (D1), the buccolingual width(L1) and mesiodistal width (L2) of mesial roots, and the flatness degree(L1/L2) of mesial roots. The results were statistically analyzed., Results: The prevalence of MMC was 9.6% when considering the number of teeth and 7.2% when considering individuals. The presence of MMC was not significantly associated with sex (p = 0.993) or age (p = 0.211). Type 1-3-2 emerged as the most prevalent root canal morphology. MMC primarily manifested within 4 mm below the canal orifices. In cases where MMC was present, the MB-ML distance was significantly greater (p = 0.017). Conversely, no significant correlation was found between the presence of MMC and the length, width, or flatness degree of the mesial roots., Conclusions: The morphology of MMCs is complex, and most of them exhibit confluent canals. In instances where MMCs are present, the MB-ML distance is significantly larger. For effective detection of MMC, a thorough examination of the area within 4 mm beneath the canal orifice is recommended., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Medical Ethics Committee of Shaanxi Provincial People’s Hospital (No. SPPH-LLBG-17-3.2). All patients have provided informed consent for the CBCT scan. Informed consent was obtained from all individual participants included in the study. All experiments were performed in accordance with relevant guidelines and regulations. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Objective: The purpose of this study was to evaluate the effect of different preparation depths (0, 2 and 4 mm) of different restoration designs (classic endocrown design versus overlay design) on marginal adaptation of restorations fabricated of two different restorative materials (lithium disilicate and PEEK)., Materials and Methods: Sixty mandibular natural molars were collected as abutments for the restorations of this study, and grouped in three main groups of different cavity depths (0, 2 and 4). Each group was divided into two subgroups according to material of fabrication to (L) for lithium disilicate (IPS emax CAD, Ivoclar vivadent, Switzarland) and (P) for PEEK (Bio-hpp, Bredent, Germany). CAD/CAM milling technology was used for fabrication of restorations. After cementation of restorations over abutments, hydrothermal aging was performed, and then marginal adaptation was evaluated via micro CT technology., Results: Regarding cavity depths, there was a significant difference between different groups (p < 0.001). The highest value was found in samples with 4 mm extension (84.35 ± 18.16), followed by samples with 2 mm extension (66.52 ± 21.86), while the lowest value was found in samples without pulpal extension (59.41 ± 22.16). Post hoc pairwise comparisons showed samples with 4 mm extension to have a significantly higher value than samples without extension (p < 0.001). Regarding materials of fabrication, PEEK (85.32 ± 12.37) had a significantly higher value than Emax (54.86 ± 20.86) (p < 0.001)., Conclusions: Increasing intrapulpal cavity depths increases vertical marginal gap of lithium disilicate or PEEK restorations. Endocrowns fabricated of lithium disilicate show less marginal discrepancies than that of endocrowns fabricated of PEEK., Competing Interests: Declarations. Ethics approval and consent to participate: The Research Ethics committee, Faculty of dentistry, Ain Shams University approved all experimental methods and the study was performed in accordance with its regulations, licensing requirements and relevant guidelines. Because this study did not contain any intervention with human participants or animals and it only utilized archival teeth whose owners cannot be identified, it was exempt from ethical assessment. The approval of the ethics committee is Fdasu-RecD031819. The need for informed consent was waived by the ethical committee of the Ain Shams University, Cairo, Egypt. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: The purpose of this study was to evaluate the validity of near-infrared light reflection for detecting different depths of proximal caries in posterior teeth and to compare it with commonly used clinical oral examinations and bitewing radiography images., Methods: Twenty-six patients with a total of 516 proximal surfaces were included in this study. The ground truth of the proximal caries was determined through a consensus reached by two experienced dentists after an intraoral examination assisted by bitewing radiographs. Two general dentists assessed the condition of proximal caries on posterior teeth on near-infrared light reflection images. Accuracy, sensitivity, and specificity were evaluated to determine the diagnostic efficacy of near-infrared light reflection for detecting proximal caries in posterior teeth., Results: For posterior teeth, the accuracy of near-infrared light reflection was 0.78, with a sensitivity of 0.44 and a specificity of 0.83. Cohen's kappa showed poor consistency between the two diagnostic methods, near-infrared light reflection and bitewing radiography., Conclusion: Near-infrared light reflection is an effective clinical tool for detecting proximal caries in posterior teeth, yet this method does not demonstrate superiority over traditional methods such as bitewing radiography., Trial Registration: The clinical trial was registered with the China Clinical Trial Registry ( https://www.chictr.org.cn/ ) on 18 August 2023 under the trial number ChiCTR2300074877., Competing Interests: Declarations. Ethics approval and consent to participate: Ethics approval: This study protocol was reviewed and approved by [Ethics Committee of Zhejiang Provincial People’s Hospital, China], approval number [QT2023172]. Consent for publication: Not applicable. Consent to participate: All data collection and recordings were performed anonymously, and written informed consent was obtained from all patients before they underwent the examination. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

As photobiomodulation is growing in the dental field the aim of this prospective, two-arm clinical trial was to assess the radiographic changes for chronic periapical bone lesions related to mandibular molars after primary root canal therapy with or without applying Diode laser on soft tissue. The samples were randomly divided into a Laser group and a mock laser (ML) group. Preoperative CBCT images were compared 12 months later with postoperative CBCT to gauge the changes in the volume of the bony lesion by two observers. The kappa coefficient was calculated to assess the intra-observer agreement. Data were presented as median, mean, and standard deviation (SD) values. For parametric data (age), a Student's t-test was used. Qualitative data (Gender) was presented as frequencies and percentages and then analyzed by Chi-square test. The Wilcoxon signed-rank test was used to compare CBCT measurements pre- and post-treatment. The significance level was set at P ≤ 0.05. The collected data in this study showed that there was no statistically significant difference between median volumes of the periapical lesion in the Laser and ML groups (P-value = 0.564, Effect size = 0.237) and (P-value = 0.452, Effect size = 0.310), respectively while, there was a statistically significant decrease in the volume of periapical lesion post-treatment within each group (P-value < 0.001). The size of the periapical bony lesion decreased significantly after conventional endodontic treatment whether Laser was applied or not. The study protocol was enrolled as NCT04311905 at www.clinicaltrials.gov database on (17/03/2020) after the approval of the Ethics Committee, Faculty of Dentistry, Ain Shams University (FDASURecID091703)., Competing Interests: Declarations. Ethical approval: This study was designed and reported by adhering to the Consolidated Standards of Reporting Trials statement CONSORT. It was assessed and then approved by the Ethics Committee, Faculty of Dentistry, Ain Shams University (Approval code: FDASURecID091703). The study was performed per the Declaration of Helsinki. Consent to participate: Informed consent was obtained from all subjects and/or their legal guardian(s).Consent to publish The authors affirm that participants provided informed consent for the publication of the images in Figure(s) 2 and 3. All patients signed informed consent regarding publishing their data. Consent to participate: The authors have stated explicitly that there are no conflicts of interest in connection with this article., (© 2024. The Author(s).)

The preservation of the original configurations of root canals during endodontic preparation is crucial for treatment success. Nickel-titanium (NiTi) rotary systems have been refined to optimize canal shaping while minimizing iatrogenic errors. This study aimed to evaluate and compare the shaping efficacy of the novel R-Motion (RM) and the established WaveOne Gold (WG) systems using micro-computed tomography (micro-CT). Twenty-four mesial canals of 12 double-rooted extracted mandibular first molars were randomly assigned to either the RM or WG groups, with the mesiobuccal (MB) and mesiolingual (ML) canals allocated accordingly. Root canals were prepared following the manufacturer's protocols. In the RM group, crown-down technique up to a 25/0.06 taper was employed. For the WG group, the preparation was completed with a WG primary file (25/0.07 taper). Specimens were scanned using micro-CT scans before and after instrumentation to establish baseline and post-instrumentation datasets. The following parameters were evaluated, and values were calculated to compare the shaping ability of the two files: percentage of untouched canal walls, changes in surface area, canal volume, dentin thickness, canal angulation, structure model index, canal transportation, and centering ability ratio. Data were analyzed using IBM SPSS Statistics for Windows, Version 23.0 (IBM Corp., Armonk, NY), with a statistical significance set at P ≤ 0.05. Micro-CT analysis demonstrated comparable untouched canal surface areas and changes in surface area and volume between both RM and WG systems. Both systems effectively straightened canal curvature without significant differences in canal angulation. The RM files exhibited a statistically lower reduction in dentin thickness, indicating better preservation of structural integrity. Both RM and WG files displayed similar effective shaping abilities. However, RM caused less dentin removal and canal transportation. Thus, RM is recommended for its ability to balance effective canal shaping with structural preservation in a conservative manner., Competing Interests: Declarations. Ethics approval and consent to participate: All methods were carried out in accordance with relevant guidelines and regulations. All experimental protocols were approved by the Research Ethics Committee of the Faculty of Dentistry, King Abdulaziz University (approval number: 37-02-24). Informed consent was obtained from all subjects and/or their legal guardian(s). Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: The surgical complexity associated with the palatal roots of maxillary molars was considerably elevated. Previous studies on the relationships between maxillary molar roots and the maxillary sinus or cortical plates have focused on individual root observation without considering the positional relationship between buccal and palatal roots or analysing the surgical pathway of maxillary molar palatal roots. This study aimed to investigate the relationship between maxillary molar palatal roots and adjacent anatomical structures to provide a reference for performing palatal roots endodontic microsurgery., Methods: Anatomical characteristics of the maxillary molar roots were determined using cone-beam computed tomography (CBCT) imaging data from 250 patients. The relationship between the root apex plane (RAP) and the maxillary sinus floor (MSF) was categorized into two types (Type I and Type II) based on whether the RAP was higher than the MSF or not. There were also two subclasses for Type I and Type II, which included Type I-a (RAP was lower than MSF), Type I-b (RAP and MSF were on the same plane), Type II-a (root apex protruded into the maxillary sinus) and Type II-b (root apex did not protrude into the maxillary sinus, but the RAP was higher than the MSF). Distances from the root apexes to the MSF and the cortical bone surface were measured., Results: Of 500 teeth, 1352 roots were evaluated. Buccal roots obstruction 3 mm from the palatal root apex were present in almost all maxillary molars. The proportion of Type II-b cases in the palatal roots of three-rooted maxillary molars was significantly higher than that in the mesiobuccal (MB) and distalbuccal (DB) roots (P < 0.01). The distance from the root apex to the MSF increased with age and was significantly longer in females than in males (P < 0.05). The average distance from the apexes of palatal roots to the buccal cortical plate was 10.12 mm for first molars and 10.53 mm for the second molars. When measured through the MB roots, the distance to the buccal cortical plate was significantly shorter than that through the DB roots in the first molars (P < 0.05); however, the opposite was observed in the second molars (P < 0.05)., Conclusions: For determining the relationship between maxillary molar palatal roots and adjacent structures, CBCT provides reliable information, which acts as the basis for performing endodontic microsurgery of the palatal roots. Understanding the relationship between the roots of the maxillary molar and neighbouring anatomical structures helps surgeons evaluate potential difficulties, select optimal strategies, and reduce complications., Clinical Trial Number: Not applicable., Competing Interests: Declarations. Ethics approval and consent to participate: The Medical Ethics Committee of Beijing Stomatological Hospital, Capital Medical University, approved this study (approval number: CMUSH-IRB-KJ-PJ-2023-11). The study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments. Written informed consent was obtained from all participants prior to the study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: To evaluate the prevalence and characteristics of taurodontism in northern China by using cone-beam computed tomography (CBCT) and assisting the treatment., Methods: The study involved CBCT scans of 8112 teeth from 507 participants of northern China, comprising 217 males and 290 females aged 18 to 60. Analysis was conducted using Shifman and Chanannel's criteria to assess the prevalence and attributes of taurodontism, examining differences based on tooth position (maxilla and mandible) as well as gender (P < 0.05). Specific morphology including C-shaped canal was recorded. The curvature of the canals was measured using a modified Schneider method. Moreover, we reported two failure cases with taurodontism referred to a retreatment., Results: Taurodontism was observed in 113 participants, affecting 23.50% of the males and 21.38% of the females in at least one tooth (P > 0.05). The prevalence was significant higher in maxilla (P < 0.05). The highest incidence of taurodontism was detected in premolars, 9.86% in the maxillary first premolars, and in molars, with 3.94% in the maxillary first molars. Regarding canal curvature, a higher incidence of curved canal could be found in maxillary and mandibular molars of taurodontism (47.50-66.67%), alongside an elevated prevalence of C-shaped taurodontism in mandibular second molars (71.43%). After follow-up, the healing response was satisfactory in both cases., Conclusion: The study highlighted a higher incidence of taurodontism in maxilla, indicating a significant association between taurodontism, C-shaped characteristics, and canal curvature. Dentists are advised to carefully consider the presence of special morphologies during taurodontism treatment., Competing Interests: Declarations. Ethics approval and consent to participate: The CBCT images used in this study were obtained from Beijing stomatological hospital, Capital medical university. All methods have been approved by Institutional Review Board of Beijing Stomatological Hospital, Capital Medical University with the approval number CMUSH-IRB-KJ-PJ-2024-08). Informed consent was obtained from all subjects and/or their legal guardian(s). Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: This retrospective study aims to characterise the root canal morphology of maxillary and mandibular second molars using cone-beam computed tomography (CBCT). The number of roots and canal configurations were evaluated using both the Vertucci and Benjamı´n Brisen˜ o Marroquı´n classification systems., Methods: A total of 1084 second molar images (523 maxillary; 266 right and 257 left side and 561 mandibular; 285 right and 276 left side) were evaluated from 320 CBCT scans analyzed for the Turkish subpopulation. CBCT imaging provided superior visualisation of root canal anatomy compared to periapical radiography. The findings revealed diverse root canal configurations, with variations observed even within the same population. Statistical analyses, including the chi-squared test, were used to assess correlations between root number and demographic variables such as age and sex., Results: According to Benjamı´n Brisen˜ o Marroquı´n classification system, the most common configuration for upper right three-rooted teeth mesial root was 3 URM 2-1 (n:66, 35.7%), for distal root was 3 URM 1 (n:169, 91.4%), and for palatal root was 3 URM 1 (n:165, 89.2%). Additionally, the most common configuration for upper left three-rooted teeth mesial root was 3 27 1 (n:50, 28.4%), for distal root was 3 ULM 1 (n:160, 90.9%), and for palatal root was 3 ULM 1 (n:158, 89.8%). In lower left molars, the most common configuration in the two-rooted teeth mesial root was 2 LLM 2 (n:114, 49.4%), and for the distal root was 2 LLM 1 (n:170, 73.6%). For lower right the most common configuration for two-rooted teeth mesial root was 2 LRM 2 (n:125, 52.5%), and for distal root was 2 LRM 1 (n:173, 72.7%)(p < 0.05)., Conclusion: The primary outcome was observed that the root canal anatomy of upper and lower second molars may differ in both classifications of Turkish subpopulation. While Vertucci's classification was inadequate in some cases, Briseno-Marroquin classification was able to classify all upper and lower second molars with a single code. This new classification is a more useful system for classifying all second molars. There is a statistically significant difference exists among the new configuration according to the distribution of the teeth analyzed., Competing Interests: Declarations. Ethics approval and consent to participate: Non-Interventional Clinical Research Ethics Committee of Istanbul Medipol University approved the study and informed consent to participate was waived (E-10840098–202.3.02–2246). This study was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants and images were anonymised. Consent for publication: NA. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Objectives: To determine and compare pulp volume, dentin mineral density, presence of microcracks, pulp stones, and accessory canals, as well as their localizations in root regions for hypomineralized and healthy teeth., Design: This study included 60 extracted permanent molar teeth, categorized into hypomineralized and healthy groups (n = 30 each). The hypomineralized group comprised molar teeth with limited white, yellow, or brown opacities, post-eruptive breakdown, or extensive restoration or crown damage. The healthy group included caries-free molar teeth without these characteristics. Using 3D micro-computed tomography images pulp volume, dentin mineral density, and the presence and locations of microcracks, pulp stones, and accessory canals were determined for each group. Statistical analyses were conducted using Independent T-test and Chi-square test, with significance set at p < 0.05., Results: There was no statistically significant difference between the groups regarding pulp volume and microcracks (p ≥ 0.05). The number of accessory canals was significantly greater in the cervical (p = 0.011; p < 0.05) and middle (p = 0.010; p < 0.05) regions of the hypomineralized teeth than healthy teeth. Dentin mineral density was statistically higher in the apical, middle, and cervical root regions (p < 0.001; p < 0.05); however, the number of pulp stones was found to be greater in the cervical regions of healthy teeth compared with those with hypomineralization (p = 0.026; p < 0.05)., Conclusion: There were lower dentin mineral density measurements, a decreased number of pulp stones in the cervical region, and a greater number of accessory canals in the middle and cervical regions of hypomineralized teeth compared with healthy teeth., Competing Interests: Declaration of Competing Interest 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., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Changes in healthy and inflamed pulp on periapical radiographs are traditionally so subtle that they may be imperceptible to human experts, limiting its potential use as an adjunct clinical diagnostic feature., Aim: This study aimed to investigate the feasibility of an image-analysis technique based on the convolutional neural network (CNN) to detect irreversible pulpitis in primary molars on periapical radiographs (PRs)., Design: This retrospective study was performed in two health centres. Patients who received indirect pulp therapy at Peking University Hospital for Stomatology were retrospectively identified and randomly divided into training and validation sets (8:2). Using PRs as input to an EfficientNet CNN, the model was trained to categorise cases into either the success or failure group and externally tested on patients who presented to our affiliate institution. Model performance was evaluated using sensitivity, specificity, accuracy and F1 score., Results: A total of 348 PRs with deep caries were enrolled from the two centres. The deep learning model achieved the highest accuracy of 0.90 (95% confidence interval: 0.79-0.96) in the internal validation set, with an overall accuracy of 0.85 in the external test set. The mean greyscale value was higher in the failure group than in the success group (p = .013)., Conclusion: The deep learning-based model could detect irreversible pulpitis in primary molars with deep caries on PRs. Moreover, this study provides a convenient and complementary method for assessing pulp status., (© 2024 BSPD, IAPD and John Wiley & Sons Ltd.)

Objectives: To identify if supplemental preoperative cone beam CT (CBCT) imaging could improve outcomes related to endodontic access cavity preparation, using 3D-printed maxillary first molars (M1Ms) in a rigorously simulated, controlled human analogue study., Methods: Eighteen operators with 3 experience-levels took part in 2 simulated clinical sessions, 1 with and 1 without the availability of CBCT imaging, in a randomized order and with an intervening 8-week washout period. Operators attempted the location of all 4 root canals in each of 3 custom-made M1Ms (2 non-complex and 1 complex mesiobuccal [MB] canal anatomy). The primary outcome was tooth volume removed. Secondary outcomes were linear cavity dimensions, canals located, and procedural time. Operator confidence and "helpfulness" of available imaging were recorded. Statistical analysis of data included: paired t-tests, Fisher's exact test, linear mixed-effect modelling, and Mann-Whitney U test, with an alpha level of .05 for all., Results: When supplemental preoperative CBCT was available, there were significant reductions in volume of the access cavity and procedural times, with significantly increased MB2 canal location, but only for teeth with non-complex anatomies and for more experienced operators. Linear mixed-effect modelling identified image type and operator experience as significant predictors of tooth volume removed and procedural time. There was significantly lower confidence in canal location and perceived "helpfulness" (all Experience Groups) when conventional imaging only was used compared with when CBCT was available., Conclusions: Supplemental preoperative CBCT had several beneficial impacts on access cavity preparation, although this only applied to teeth with non-complex anatomy and for more experienced operators., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology and the International Association of Dentomaxillofacial Radiology.)

Objective: proximal enamel caries lesions (PEC) are believed to initiate and progress to cavitation below the proximal contact area (PCA), but no evidence exists on the location of initial carious cavitation on the proximal surface with functional PCA. This study aimed to test the association of anatomical areas of the proximal surface with the severity of PEC and the frequency of cavitation in PEC in primary molars DESIGN: laboratory, observational, transversal study. Exfoliated primary molars (n = 33) with functional PCA (biofilm-free PCA surrounded by biofilm) had their proximal surfaces (one/tooth) divided anatomically into up to nine areas: 3 areas based on the occlusal/cervical PCA boundaries (areas I, II, and III; occluso-cervically) and 3 areas based on the bucco/lingual PCA boundaries (A, B, and C), with area IIB representing the PCA and area IIIB as the sub-PCA (below the PCA). PEC (ICDAS scores 1 and 2-3) and cavitation in PEC were quantified in all areas using stereomicroscopy and microCT. PEC volume was quantified in areas IIB and IIIB under microCT RESULTS: PEC severity increased occluso-cervically. PCA and sub-PCA presented different PEC severities (higher in sub-PCA) and similar PCE volumes, but the odds of carious cavitation were much higher (Odds ratio = 197.4; 95 % CI: 8.7/4480.7) in the PCA than in the sub-PCA (no cavitation)., Conclusion: PCA presented lower PEC severity and similar PEC volume compared to sub-PCA, but PCA concentrated all cavitations in PEC, supporting a new model for the pathogenesis of PEC., Competing Interests: Declaration of Competing Interest 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., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: The conicity of the root canals of primary teeth is an important measure for endodontic therapies. However, determining this conicity depends on the methods employed, which requires further investigation., Aim: The aim of this study was to determine the conicity of the root canals of the upper and lower primary second molars using nanotomography (nCT)., Design: An in vitro study was performed using nine primary second molars, both upper and lower, subjected to nCT. Comparisons between the diameters of root canals were performed between the thirds (cervical-D0, middle-D5, and apical-D7). The conicity (%) was determined for each root canal from cervical to apical. Data were statistically analyzed with a significance level of 5%., Results: The conicity ranged from 2% to 8% for the upper primary second molars. Significant differences in root canal diameter between the thirds (D0, D5, and D7 points) were observed in the mesio- and distobuccal roots (p < .05), but not in the palatal roots (p > .05). For the lower primary second molars, the conicity ranged from 2% to 17%, as well as significant differences in root canal diameter between the thirds (D0, D5, and D7 points) were observed in all roots (distal, mesiobuccal, and mesiolingual; p < .05)., Conclusion: The conicity of the upper primary second molars was different from that of the lower ones, which showed a greater variability., (© 2024 BSPD, IAPD and John Wiley & Sons Ltd.)

Objective: The primary focus of this investigation was to evaluate the biomechanical effects of high trimline design aligners on the distalization of mandibular molars, employing three-dimensional finite element analysis (3D-FEA). The study concentrated on aspects such as tooth movement, stress distribution, and anchorage control., Methods: Utilizing Cone-beam computed tomography (CBCT) data, a detailed 3D geometrical model was constructed for finite element analysis. This model was used to assess four variations of aligner trimlines, alongside the employment of Class III traction. Analyses were conducted to examine stress distributions and tooth displacements in these different scenarios., Results: Aligners with a high trimline design were found to be more effective in facilitating the distal movement of mandibular molars than those with scalloped trimlines, providing improved management over tooth movement and stress distribution. In specific configurations where Class III traction was applied, a reduction in the deformation of anterior teeth was observed, which enhanced anchorage stability. Nevertheless, the anterior teeth in all configurations were subjected to compressive stresses that surpassed thresholds likely to induce external root resorption, underlining the importance of vigilant monitoring., Conclusions: The research verified the biomechanical advantages of high trimline aligners in the distal movement of mandibular molars and underscored the critical role of aligner design and traction application in optimizing orthodontic treatment outcomes. Additionally, it raised concerns regarding the potential for root resorption due to significant stress in the periodontal ligament, necessitating thorough observation of patients, particularly those fitted with high trimline aligners. Despite these insights, the study's findings are derived from the data of a single patient, suggesting a need for further investigations involving broader samples and extended clinical assessments., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Ethics Committee of Beijing Stomatological Hospital, Capital Medical University (No. CMUSH-IRB-KJ-PJ-2024-26). All methods were performed in accordance with the Declaration of Helsinki. Consent for publication: Written informed consent was obtained from participants for the publication of any potentially identifiable data included in this study. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Objective: To investigate the prevalence and characteristics of taurodontism in patients with cleft lip and palate (CLP) and clarify the relationship between CLP and the frequency and severity of taurodontism., Methods: CBCT scans of 30 patients with bilateral CLP (BCLP), 70 with unilateral CLP (UCLP) and 70 healthy individuals were taken for investigation. In each group, the first and second molars were assessed for the presence of taurodontism. In taurodontic teeth, the severity of taurodontism was measured and classified based on the taurodontic index (TI). The frequency and severity of taurodontism were compared between the three groups., Results: Taurodontism was significantly higher in patients with CLP (P < 0.001), and its prevalence was significantly higher in patients with BCLP than those with UCLP (P = 0.003) and the control group (P < 0.001). There was no difference among the three groups regarding the severity of taurodontism. Additionally, the frequency of taurodontism in the second molars was significantly higher than that in the first molars in the control group (P = 0.019)., Conclusion: Based on this investigation, clinicians should be aware of the possible complications that may occur when performing dental procedures on patients with BCLP and UCLP due to the higher incidence of taurodontism in these patients.

This study aimed to develop a deep learning system for the detection of three-rooted mandibular first molars (MFMs) on panoramic radiographs and to assess its diagnostic performance. Panoramic radiographs, together with cone beam computed tomographic (CBCT) images of the same subjects, were retrospectively collected from 730 patients, encompassing a total of 1444 MFMs (367 teeth were three-rooted and the remaining 1077 teeth were two-rooted). Five convolutional neural network (CNN) models (ResNet-101 and - 50, DenseNet-201, MobileNet-v3 and Inception-v3) were employed to classify three- and two-rooted MFMs on the panoramic radiographs. The diagnostic performance of each model was evaluated using standard metrics, including accuracy, sensitivity, specificity, precision, negative predictive value, and F1 score. Receiver operating characteristic (ROC) curve analyses were performed, with the CBCT examination taken as the gold standard.Among the five CNN models evaluated, ResNet-101 demonstrated superior diagnostic performance, and the AUC value attained was 0.907, significantly higher than that of all other models (all P < 0.01). The accuracy, sensitivity, and specificity were 87.5%, 83.6%, and 88.9%, respectively. DenseNet-201, however, showed the lowest diagnostic performance among the five models (all P < 0.01), with an AUC value of 0.701 and an accuracy of 73.2%. Overall, the performance of the CNNs diminished when using image patches containing only the distal half of MFMs, with AUC values ranging between 0.680 and 0.800. In contrast, the diagnostic performance of the two clinicians was poorer, with AUC values of only 0.680 and 0.632, respectively. In conclusion, the CNN-based deep learning system exhibited a high level of accuracy in the detection of three-rooted MFMs on panoramic radiographs., Competing Interests: Competing interests: The authors declare no competing interests. Ethical approval: Approval for this study was obtained from the Institutional Ethics Committee (IEC) for Human Research (Issuing Number: KY2022-089-01). Due to the retrospective nature of the study, the IEC of Suzhou Ninth People’s Hospital waived the need of obtaining informed consent. The study was performed in accordance with the Declaration of Helsinki., (© 2024. The Author(s).)

Background: Radiographs play a key role in diagnosis of periodontal diseases. Deep learning models have been explored for image analysis in periodontal diseases. However, there is lacuna of research in the deep learning model-based detection of furcation involvements [FI]. The objective of this study was to determine the accuracy of deep learning model in the detection of FI in axial CBCT images., Methodology: We obtained initial dataset 285 axial CBCT images among which 143 were normal (without FI) and 142 were abnormal (with FI). Data augmentation technique was used to create 600(300 normal and 300 abnormal) images by using 200 images from the training dataset. Remaining 85(43 normal and 42 abnormal) images were kept for testing of model. ResNet101V2 with transfer learning was used employed for the analysis of images., Results: Training accuracy of model is 98%, valid accuracy is 97% and test accuracy is 91%. The precision and F1 score were 0.98 and 0.98 respectively. The Area under curve (AUC) was reported at 0.98. The test loss was reported at 0.2170., Conclusion: The deep learning model (ResNet101V2) can accurately detect the FI in axial CBCT images. However, since our study was preliminary in nature and carried out with relatively smaller dataset, a study with larger dataset will further confirm the accuracy of deep learning models., Competing Interests: Declarations. Ethics approval and consent to participate: All methods were carried out in accordance with relevant guidelines and regulations. All experimental protocols were approved by the Research ethics committee. Ref. no. REC-23-10-12-01-F (University of Sharjah). Informed written consent was obtained from all subjects involved in the study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests. Clinical trial number: Not applicable. Competing interests: The authors have no competing interests to declare., (© 2024. The Author(s).)

Aim: To evaluate the agreement between six currently available periapical radiography-based methods for measuring the root canal curvatures in mesial roots of mandibular first molars, assessed by two examiners with different proficiency levels., Methodology: Non-endodontically treated mesial roots of 41 human mandibular first molars were radiographed using the parallelling technique. Two independent observers (a specialist in endodontics and radiology and a final-year dental student) assessed their root canal curvature using the methodologies described by Schneider (1971, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 32, 271), Weine (1982, Endodontic therapy), Berbert and Nishiyama (1994, Revista Gaúcha de Odontología, 356), Luiten et al. (1995, Journal of Endodontics, 21, 26), Hankins and ElDeeb (1996, Journal of Endodontics, 22, 123) and Pettiette et al. (1999, Journal of Endodontics, 25, 230). Intra- and inter-examiner reliability was assessed using the intraclass correlation coefficient. The differences in curvature angle measured by the different methods were compared using the one-way anova for repeated measures test, followed by Tukey's post hoc analysis. The effect was calculated using the Cohen's d method. To determine the agreement between methods, the Bland-Altman analysis was used. The significance level was set at 5%., Results: Agreement for the observers was excellent (>0.81) for the six methods considered. For the angle comparisons between methods, the maximum differences were for Schneider versus Weine (35.77°) and Luiten versus Hankins (35.14°), whilst the highest percentage of angles with a difference >10° were Weine versus Luiten and Berbert versus Pettiette (90%) and the comparison Weine versus Hankins presented with the lowest frequency (15%). Excellent agreement was found for five comparisons: Weine versus Luiten (0.940), Berbert versus Pettiette (0.917), Weine versus Pettiette (0.907), Luiten versus Pettiette (0.904) and Berbert versus Luiten (0.812). Compared to Schneider's method, the other methods showed a tendency of increasing difference as the angles became more acute. The other methods exhibited linear differences, remaining constant for smaller and larger angles., Conclusions: Reliability was excellent for all methods assessed separately. Maximum differences in curvature angles were found when comparing Schneider versus Weine and Luiten versus Hankins. Excellent agreement was found for Weine versus Luiten, Berbert versus Pettiette, Weine versus Pettiette, Luiten versus Pettiette and Berbert versus Luiten. In the presence of dilacerations, the method by Schneider was less sensitive., (© 2024 The Author(s). International Endodontic Journal published by John Wiley & Sons Ltd on behalf of British Endodontic Society.)

Bifid mandibular canals are common anatomical findings with variations based on direction and location of branching, which carry significant clinical implications for endodontic and surgical dental procedures. This case report describes a previously unreported ectopic dental canal that branches off the superior border of the mandibular canal, enters the apex of a mandibular second molar, traverses through the root, anastomoses with the root canal system, and subsequently exits through the lingual aspect of the root. The anastomosis of this ectopic dental canal with the mesial lingual canal led to significant bleeding during rotary instrumentation. This unique anatomical variation demonstrates the importance of a thorough cone-beam computed tomography analysis to identify critical structures prior to undertaking dental procedures involving the root apices of mandibular posterior teeth and adjacent areas., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Background: This study evaluated the accuracy of the CBCT reconstruction model compared to the natural tooth and the accuracy of the replica tooth compared to the natural tooth., Objective: The hypothesis was that a replica tooth could be used as a surgical guide in autotransplantation., Methods: Three teeth were chosen and a CBCT reconstruction model was formed from each tooth. STL-data was transferred to a milling machine and replica teeth were milled from PEEK. A digitized surface model was prepared from the natural and the replica teeth by a stereophotogrammetry scanner. The surface model from the optical scan of the natural tooth was compared to the CBCT reconstruction model and the surface model of the replica tooth. The models were matched on each other, and surface-based rigid registration was performed between the surface models. Distances were calculated and visualized by MATLAB., Results: The CBCT reconstruction model and the natural tooth were compared. The largest euclidean distance was found at the root tip in the premolar (0.93 mm) and at the furcation area in the molar (2.3 mm). When the natural tooth and the replica tooth were compared, the largest euclidean distance was found at the root tip in the premolar (1.5 mm) and at the furcation area in the molar (1.9 mm)., Conclusion: A CBCT scan maintains sufficient image quality for tooth autotransplantation planning. The replica tooth corresponded in size and shape to the natural tooth in terms of clinically expected need of precision., (© 2024 The Author(s). Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

Objectives: To investigate the alveolar bone morphology of the mandibular second and third molars in skeletal Class III patients from a buccolingual direction., Methods: Sixty skeletal Class III patients were recruited. The alveolar bone width, buccal cortical bone thickness and lingual cortical bone thickness were measured in five planes from mesial to distal and at five depths from gingival to root. The effects of the gender of the patients, the second molar lingual inclination and the third molar on alveolar bone width and cortical bone thickness were evaluated. To explore the effect of third molar extraction on alveolar bone morphology, the measurements before and after third molar extraction were compared., Results: The impacted third molar had significantly greater alveolar bone width and thicker buccal cortical bone at the cervical third of the molar, while the erupted third molar had greater alveolar bone width at the apical third. Three weeks after third molar extraction, these advantages would weaken owing to the reconstruction of the alveolar bone. Patients with lingually inclined molar were observed to own thicker lingual cortical bone. Males tended to have greater alveolar bone width, but no significant differences were shown in this study., Conclusions: The growth of the third molar and the second molar lingual inclination affect the alveolar bone morphology of the mandibular second and third molars significantly, but gender has trivial effects on the morphology. The alveolar bone morphology of the mandibular second and third molars would change 3 weeks after third molar extraction., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The aim of this study was to evaluate the gingival vascular response to mechanical compression during inflammation using ultrasonography. Four female and 4 male Sinclair mini pigs 18 mo of age were included in the study. Pathogenic bacteria-impregnated silk ligatures were placed around the third premolars (PM3), fourth premolars (PM4), and first molars (M1). Ligatures were placed per quadrant at 2-wk intervals in random order. Ultrasonographic study was performed at 2-wk intervals following baseline until the 10th week. Brightness mode (B-mode) images and color flow cine loops were captured at 2 different conditions: 1 with only coupling gel between the ultrasound transducer and the mucosal surface and 1 with the transducer compressing the mucosal surface. The compression was visually adjusted until minimal to no blood flow was detected in color-flow mode. Compression was facilitated using a solid gel pad attached to the transducer. Strain values were obtained from B-mode images of the gel pad and plotted versus study weeks. The t test comparisons were obtained to the baseline (week 0). Data from female and male pigs were plotted and analyzed separately for comparison. Gel pad strain increased with peak around week 4 and gradually decreased in both sexes. In male pigs, the increase in strain was statistically significant in weeks 2, 4, and 6 of all teeth regions and week 8 of PM4 and M1 regions. In female pigs, the increase in strain was significant in only week 4 of PM4. Higher strain required for stoppage of blood flow implies increased gingival blood flow with inflammation, which corresponds with previous studies. Considerably smaller changes in gel pad strain were noted from female pigs, indicating a smaller increase in gingival blood flow compared with males. This study demonstrated a possible application of intraoral ultrasonography for assessment of gingival inflammation., Competing Interests: Declaration of Conflicting InterestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The authors declare no perceived or actual conflicts of interest. The corresponding author confirms that all coauthors have reported any potential conflicts.

This study aimed to evaluate and compare the shaping abilities and minimum dentin thickness of minimally invasive rotary instruments via micro-computed tomography. Twelve 3D-printed C-shaped canal models from a mandibular molar were divided into two groups, and root canals were prepared with either XP-endo Rise (XR) or TruNatomy (TN) systems. Pre- and post-preparation evaluations included canal volume, prepared area and minimum dentin thickness. No significant differences were found in canal volume change (XR: 22.66 ± 4.28%, TN: 23.02 ± 5.10%), prepared canal area (XR: 31.86 ± 10.72%, TN: 30.26 ± 11.59%) and minimum dentin thickness (XR: 0.30 ± 0.05 mm, TN: 0.28 ± 0.05 mm) between groups (p > 0.05). The canal volume change in the middle third was significantly higher than that in the coronal and apical thirds (p < 0.05) in both groups. In conclusion, XR demonstrated comparable shaping abilities and minimum dentin thickness to TN in preparing 3D-printed C-shaped canals., (© 2024 Australian Society of Endodontology Inc.)

Objectives: The aim of this retrospective study is to evaluate the effect of age and gender on the alveolar bone destruction pattern with cone beam computed tomography (CBCT) in the posterior region of the maxilla., Materials and Methods: The study group included CBCT image records of 361 consecutive patients (180 males and 181 females) aged 20 years and older. Alveolar crest morphology in the maxillary right and left first and second molar teeth on retrospective images was classified as a horizontal or vertical defect (one-walled, two-walled, three-walled, and combined bone defect) on four surfaces (mesial, distal, buccal, and palatinal). Bone crater defects were defined, and furcation involvements and combined periodontal-endodontic lesions (CPELs) were placed in another category., Results: In 361 patients, 1444 teeth were evaluated from adults between 20 and 63 years of age; 49.9% of the patients were male and 50.1% were female. Female patients had a considerably greater rate of one-walled horizontal damage in the right molar teeth than male patients (p = 0.002; p < 0.05). Patients with combined horizontal destruction in the right and left molar teeth, horizontal destruction in the palatinal, and horizontal three-walled destruction had a significantly higher mean age than patients without these periodontal destructions (p = 0.000; p < 0.05). Males were shown to have statistically higher frequencies of horizontal defects when defects were combined or distally and palatally located., Conclusions: Age and gender affect the alveolar bone loss pattern. Except for single-walled destructions, it has been found that the frequency of horizontal destruction increases with age. Horizontal destruction in the palatinal along with horizontal three-walled destruction increased with age., (© 2024 The Author(s). Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

The present study aimed to compare the clinical and radiographic success rates of Formocresol (FC), Portland Cement (PC), and NeoMTA Plus in primary molar pulpotomy. Ninety-six primary molars in ninety-six children aged 3‒9 years were randomly assigned to FC, PC, and NeoMTA Plus groups. Radiographic and clinical follow-up evaluations were performed at six and twelve months. After six and twelve months, clinical success rates were 100% in the three groups. The radiographic success rates in the 6-month follow-up were 96.7 and 96.7% in the FC and PC groups and 100% in the NeoMTA Plus group. At 12 months, radiographic success rate was 93.8, and 93.8% in the FC and PC groups and 96.9% in the NeoMTA Plus group. There were no significant differences between the three groups at all follow-up evaluations. NeoMTA Plus showed highest success rate, clinically and radiographically. PC and NeoMTA Plus can be considered as an alternative to FC., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Objective: To develop and validate an artificial intelligence (AI)-driven tool for automated segmentation of the pulp cavity system of mandibular molars on cone-beam computed tomography (CBCT) images., Materials and Methods: After ethical approval, 66 CBCT scans were retrieved from a hospital database and divided into training (n = 26, 86 molars), validation (n = 7, 20 molars), and testing (n = 33, 60 molars) sets. After automated segmentation, an expert evaluated the quality of the AI-driven segmentations. The expert then refined any under- or over-segmentation to produce refined-AI (R-AI) segmentations. The AI and R-AI 3D models were compared to assess the accuracy. 30% of the testing sample was randomly selected to assess accuracy metrics and conduct time analysis., Results: The AI-driven tool achieved high accuracy, with a Dice similarity coefficient (DSC) of 88% ± 7% for first molars and 90% ± 6% for second molars (p > .05). The 95% Hausdorff distance (HD) was lower for AI-driven segmentation (0.13 ± 0.07) compared to manual segmentation (0.21 ± 0.08) (p < .05). Regarding time efficiency, AI-driven (4.3 ± 2 s) and R-AI segmentation (139 ± 93 s) methods were the fastest, compared to manual segmentation (2349 ± 444 s) (p < .05)., Conclusion: The AI-driven segmentation proved to be accurate and time-efficient in segmenting the pulp cavity system in mandibular molars., Clinical Relevance: Automated segmentation of the pulp cavity system may result in a fast and accurate 3D model, facilitating minimal-invasive endodontics and leading to higher efficiency of the endodontic workflow, enabling anticipation of complications., Competing Interests: Declarations. Ethical approval: This study was conducted following local ethics committee approval (protocol number S67798) and in compliance with the World Medical Association Declaration of Helsinki on medical research. All patient data were anonymized. Informed consent: For this study type, formal consent is not required. Competing interests: The authors declare no competing interests. Conflict of interest: The authors declare that they have no conflict of interest., (© 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).)

Objectives: The C-shaped mandibular second molars (MSMs) may pose an endodontic challenge. The aim of this study was to develop a convolutional neural network (CNN)-based deep learning system for the diagnosis of C-shaped MSMs on panoramic radiographs., Materials and Methods: Panoramic radiographs and cone beam computed tomographic (CBCT) images were collected from a hospital in China and subsequently divided into two groups. In Group A, conventional panoramic images and CBCT images were derived from the same patients (n = 730 individuals), and the dataset consisted of conventional panoramic image patches of 1453 MSMs. In Group B (n = 610 individuals), the patients underwent CBCT examinations in the absence of available panoramic images; CBCT images were acquired and utilized to generate simulated panoramic images, and the dataset consisted of image patches of 1211 MSMs. Five pretrained CNN networks (ResNet-101 and - 50, DenseNet-121 and - 161, and Inception-V3) were utilized for the classification of C-shaped and non-C-shaped MSMs. Finally, the networks trained on the Group B dataset were tested on the Group A dataset. The diagnostic performance of each model was evaluated using receiver operating characteristic (ROC) curve analysis, and the CBCT images were taken as the gold standard. The results were compared with those achieved by three dental professionals., Results: In Group A, all five networks exhibited satisfactory diagnostic performance, with AUC values ranging from 0.875 to 0.916 and accuracies ranging from 81.8 to 86.7%. No statistical differences were detected among the five CNNs. Notably, the models trained with Group B dataset (CBCT-generated panoramic images) achieved enhanced performance as tested on Group A dataset. The AUC values reached 0.984-0.996, and the accuracies ranged between 94.5% and 98.1%. CNNs outperformed dental professionals in classification performance, and the AUC values achieved by dental specialist, novice dentist, and dental graduate student were only 0.806, 0.767 and 0.730, respectively., Conclusion: CNN-based deep learning system demonstrated higher accuracy in the detection of C-shaped MSMs on panoramic radiographs compared to dental professionals. CBCT-generated panoramic images can serve as a substitute for conventional panoramic images in the training of CNN models when the quantity and quality of conventional panoramic image dataset is insufficient., Clinical Relevance: CNN-based deep learning models have demonstrated significant potential in assisting dentists with the identification of C-shaped MSMs on panoramic radiographs, which facilitating more effective, efficient and safer dental treatment., Competing Interests: Declarations Ethics approval This study was conducted in accordance with the code of ethics of the World Medical Association (Declaration of Helsinki). The approval of this study was granted by the Institutional Review Board of Suzhou Ninth People’s Hospital and informed consent were not required as all image data were anonymized and de-identified prior to analysis (KY2022-089-01). Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The occurrence of morphological deviations in root canal anatomy is challenging and can influence treatment outcomes. While mandibular second molars typically have 2 roots and 3 canals, a unique case emerged in a 23-year-old Indian male with a symptomatic permanent left mandibular second molar showing three distal, two mesial canals, and two roots. The tooth presented as non-mobile but tender on percussion. The patient was diagnosed with symptomatic irreversible pulpitis with symptomatic apical periodontitis. The presence of mid distal canal was radiographically and visually confirmed with the aid of limited FOV cone-beam computed tomography and the dental operating microscope. Successful nonsurgical root canal treatment with 6-month follow-up has been documented in this case report., Competing Interests: Declarations Ethics approval and consent Ethical approval was granted by the Ethical Review Committee of Manipal College of Dental Sciences, Mangalore Manipal Academy of Higher Education, Manipal. Written and informed consent was obtained from the patient. Consent for publication The patient provided written informed consent for the publication of identifiable information in an open-access journal. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Accurately identifying periodontal landmarks via acoustic imaging is increasingly important. Here, we evaluated the accuracy of cementoenamel junction (CEJ) identification using ultrasound by comparing it to clinical methods in 153 extracted human teeth. The distance between the CEJ to a reference point was measured using two clinical methods (visual examination and tactile sensation) as well as ultrasound imaging. Statistical analyses were performed across all teeth and sub-groups, including tooth types (incisors, cuspids, and molars/premolars), and two classifications: A- vs. B- (visually detectable or undetectable CEJ, respectively); and CL-S vs. CL-D (shallow or deep cervical lesions). In A- or CL-S teeth, ultrasound measurements highly agreed with clinical measurements, showing a 1.72-mm 95% CI for A- and 1.99-mm 95% CI for CL-S compared to visual examination, and a 1.77-mm 95% CI for A- and a 2.10-mm 95% CI for CL-S compared to tactile sensation, respectively. For 80% of A- and 76% of CL-S teeth, the difference between ultrasound and visual examination was within ± 20%. For 81% of A- and 80% of CL-S teeth, the difference between ultrasound and tactile sensation was within ± 20%. The variance of ultrasound versus clinical CEJ identifications showed a significant correlation (r = 0.6607) to the cervical lesion depth. The errors between ultrasound and clinical measurements show no significant bias across different tooth types., Competing Interests: Competing interests J.V.J. serves as a co-founder of StyloSonic, LLC., (© 2024. The Author(s).)

Aim: Aim of this case report is to present an unfamiliar case of mandibular first molar with a C-shaped root having four canals., Background: Root canal system (RCS) is generally very complex, and it is always important for every practitioner who perform root canal treatment to have a knowledge of unusual variations in the root anatomy and root canal configuration, such as the C-shaped configuration. The frequency of C-shaped root canals is more common in mandibular second molars but very rare in mandibular first molars., Case Description: A 28-year-old male patient presented with a history of spontaneous pain, intermittent in nature, in the right mandibular first molar region, for about 2 months. On clinical inspection, a large, carious lesion was noted distally in the mandibular first molar and was nonresponsive to percussion. A preoperative orthopantomograph (OPG) confirmed the involvement of pulp with widening of PDL space, and hence was diagnosed as symptomatic irreversible pulpitis with asymptomatic apical periodontitis. A nonsurgical endodontic treatment was planned. During access cavity preparation, four distinct orifices were located in the pulp chamber, which was not uncommon and hence, proceeded with obturation by the cold lateral compaction method and access cavity restoration with resin composite. Though the initial preoperative OPG or clinical examination of the access cavity did not reveal any significant morphological variation, on contrary, master-cone check radiograph had a different view from the common variation of the mandibular molar. Hence, postoperative cone beam computed tomography was conducted to verify the same, which revealed a C-shaped root with four canals, a rare morphological and unfamiliar variation of the mandibular first molar., Conclusion: An awareness and understanding of this unusual root and its root canal morphology can contribute to the successful outcome of root canal treatment., Clinical Significance: Knowledge of root morphology and the configuration of the pulpal space play an important role in ensuring thorough debridement and the outcome of root canal treatment. How to cite this article: Ravi SV, Honwad S. C-shaped Root Morphology with Four Canals in Mandibular First Molar: A Rare Case Report. J Contemp Dent Pract 2024;25(11):1077-1080.

Introduction: Periodontitis is a chronic multifactorial inflammatory disease which eventually lead to tooth loss (TL). Therefore, a retrospective study was conducted to evaluate the status of tooth survival within 11 years after non-surgical periodontal treatment (NSPT) and to analyze the risk factors especially crown-root ratio (CRR) that affected TL in Chinese with advanced periodontitis., Methods: 3481 teeth of 131 subjects who underwent NSPT were examined retrospectively within a mean follow-up period of 11.6 years. The association of risk factors including clinical and radiographic parameters with TL was assessed using univariate and multivariate Cox regression analyses. Smooth curve fitting and segmented regression model were conducted to show the nonlinear relationship and the threshold effect between CRR and the risk of TL., Results: 347 teeth were lost in 97 patients in this study. Male, diabetes mellitus, heavy-smoker, molar, probing depth (PD), attachment loss (AL), bleeding on probing (BOP), tooth mobility, and radiographic bone loss were significantly associated with tooth loss (P < 0.05). A nonlinear relationship between CRR and the risk of TL was found, with different turning point values between molars and non-molars (1.9 vs. 2.76)., Conclusions: The findings based on practice-based clinical and radiographic data do suggest a nonlinear relationship between CRR and the survival of teeth, and provide evidence to help clinicians to determine the prognosis of teeth for patients with advanced periodontitis., Clinical Significance: Based on clinical and radiographic data, this study provides an individualized basis for clinicians to judge the dental prognosis of patients with advanced periodontitis according to the different tooth sites., Competing Interests: Declaration of competing interest 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., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: This in vitro study was formulated to clarify how mandibular partial edentulous distal extension involving three missing teeth affects the virtual occlusal record (VOR) accuracy, in terms of both trueness and precision, when using two different intraoral scanners (IOSs) - the Primescan (PS) and Trios 4 (TR) scanners., Methods: A typodont model missing the left mandibular second premolar, first molar, and second molar as well as the right mandibular first molar was mounted on a semi-adjustable articulator. Four implants were placed at the sites of the missing mandibular teeth. Six pairs of stainless steel markers (diameter: 0.5 mm) were affixed to the maxillary and mandibular casts in the buccal gingiva adjacent to the implants and on the facial surfaces of teeth as reference positions for measurements. The model was digitized with an inEox X5 laboratory scanner to create a reference dataset. Intraoral scans were performed with the PS and TR scanners, with each scan duplicated 10 times to generate 20 paired IOS files. Automatic VOR generation followed the bilateral buccal scan protocol, divided into PS and TR groups (n = 10). Six subgroups of linear distances between interarch markers were assessed with Geomagic Control software, comparing deviations from the reference scan. Data normality was confirmed with the Shapiro-Wilk test. Trueness was evaluated with two-way ANOVAs and pairwise comparisons performed with Tukey's test, whereas precision was assessed with the Levene test (α=0.05)., Results: The mean linear deviation (Δd) and standard deviation (SD) of VOR were both significantly affected by marker position (P < 0.001), and a significant position × scanner interaction was detected (P < 0.001). Negative mean deviations were observed for the distally extended edentulous areas in both groups. PS scans exhibited trueness that was significantly better than that for TR scans in the D16-46, D13-43, D23-33, and D27-37 subgroups (P < 0.05), whereas there were no significant differences in the D25-35 or D26-36 subgroups. PS scanning was associated with significantly better precision than TR scanning (P < 0.001), and worse precision was observed at D27-37 for both tested IOSs., Conclusions: Mandibular partial edentulous distal extension can significantly affect VOR accuracy. The type of IOS could also affect VOR accuracy depending on the area being scanned, with better overall performance observed for the Primescan device as compared to the Trios 4 scanner. Both of these IOSs tended to underestimate VOR occlusal dimensions in mandibular distally extended edentulous areas., Clinical Significance: Mandibular distal edentulous areas can contribute to occlusal dimensions that are underestimated in digital workflows, which may result in infraocclusal discrepancies that arise when performing restorations. IOSs and VOR scanning protocols should thus be carefully considered in order to minimize these risks., Competing Interests: Declaration of competing interest 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., (Copyright © 2024. Published by Elsevier Ltd.)

Diagnosing congenitally missing second premolars (SPs) in early childhood is challenging due to variations in their calcification ages. In this study, we investigated the correlation between calcification grades of SPs and other permanent posterior teeth to aid clinicians in the early diagnosis of congenitally missing SPs. This cohort study retrospectively evaluated 6813 images from 9261 panoramic image records of children aged 42-78 months. The Nolla method was used to score calcification grades of first and SP and first and second permanent molars. Images were divided into 6 subgroups based on age with six-month intervals, and average calcification grades of teeth were analyzed by gender and categorized. The calcification grades of these relevant teeth were separately analyzed, specifically for Grade 0 and Grade 1 for SPs. Gender-based analysis revealed statistically significant differences in the calcification grades of 4 first premolars, 4 permanent first molars, and 2 permanent second molars. However, these differences were not significant for all 4 SPs and teeth numbered 17 and 27 between genders. Generally, Nolla grades were higher in girls compared to boys, except for all 4 SPs and tooth numbered 46. Furthermore, higher Nolla grades were observed in older age groups, which was consistent with expectations. The variability in calcification grades of SPs highlights the importance of understanding the calcification grades of other permanent teeth, which are more clearly visible on radiological images of young children. This knowledge could help clinicians in assessing the dental maturity of pediatric patients and facilitate early diagnosis of congenitally missing teeth., Competing Interests: The authors declare no conflict of interest., (©2024 The Author(s). Published by MRE Press.)

The study aims to evaluate the reliability of the novel dentin thickness model based on root parameters when applied to panoramic radiography images of mandibular first molar in the southern Turkish subpopulation. A total of 946 panoramic images were analyzed for the study. The samples were allocated into four age groups: Group 1(between 10 and 18), Group 2(between 19 and 30), Group 3(between 31 and 50), Group 4(between 51 and 78). The dentin thickness model measurements consisted of root dentin thickness of the mesial aspect of the distal root and distal canal width. Regression, intraclass correlation coefficient, and Durbin-Watson analyses were used for statistics. A medium correlation was detected in the dentin thickness model (R = 0.398). Root dentin thickness and canal width had a significant effect (p < 0.05), but gender did not (p > 0.05). Group 3 showed the highest accuracy (p < 0.001). Group 4 presented the lowest correlation with chronological age compared to other age groups (p < 0.001). The dentin thickness model showed a promising result for the dental age estimation with a medium correlation. The dentin thickness model included root measurements of the mesial aspect of the mandibular first molar without any crown parameters in the southern Turkish subpopulation. Gender did not affect the dentin thickness model., (Copyright © 2024 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

Introduction: This study aimed to investigate radicular dentin thicknesses in mandibular second molars (MSMs), considering variations in root configuration and the morphology of the pulp chamber floor (PCF). The types of radicular grooves and potential danger zones were also identified., Methods: A total of 149 MSMs were scanned with micro-computed tomographic imaging and classified into 4 groups according to root fusion and PCF morphology as follows: (1) 45 with fused roots and C-shaped PCFs, (2) 45 with fused roots and non-C-shaped PCFs, (3) 14 with a single canal, and (4) 45 with separated roots. The first 2 groups were subdivided into Ω-shaped, U-shaped, and V-shaped radicular groove subgroups. Measurements included minimum and mean dentin thickness from the start of the radicular groove or root bifurcation extending 5 mm apically, the ratio of outer to inner dentin thickness, and the distribution of dentin thickness., Results: Ω-shaped and U-shaped subgroups showed significant thinner minimum inner wall thickness than V-shaped subgroups at 2-5 mm from the starting point of the radicular groove in both C-shaped and non-C-shaped pulp floor categories (P < .05). The mesial roots of separated rooted MSMs showed significant thinner dentin than a non-C-shaped floor regarding minimum and mean inner thickness and mean outer thickness (P < .05). Teeth with a single canal had significantly thicker walls compared with the other 3 groups., Conclusions: In MSMs, caution must be exercised, especially in the presence of Ω-shaped and U-shaped grooves in C-shaped roots and around the root furcation of separated roots., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

This study explores the reliability of four established legal age threshold estimation approaches in a Croatian sample. We applied Haavikko stages, Demirjian stages, Olze's third molar eruption stages, and second and third molar maturity indices measurement in 593 orthopantomograms of Croatian children and adolescents aged 11.00-20.99 years old. The left mandibular second and third molar were assessed. Logistic regression analysis was conducted to test the significance of predictive variables. Logistic Receiver operating characteristic (ROC) curves were performed to evaluate the classification ability of variables for estimating 14- and 16-year-old thresholds. The areas under the ROC curve (AUC), accuracy (Acc), sensitivity (Se), specificity (Sp), Positive Likelihood Ratio (LR +), Negative Likelihood Ratio (LR-), and Bayes post-test probability (Bayes PTP) were calculated to evaluate classification performance. Results suggest that the combination of I 2M &I 3M is the best classifier for the 14-year-old threshold (AUC = 0.879); for males alone, I 2M is an even better classifier (AUC = 0.881). The highest Acc 80.1% (95%CI, 75.9%-83.9%), Bayes PTP 86.5% (95%CI, 82.8%-89.7%) and Sp 88.9% (95%CI, 83.0%-93.3%) were by I 3M  < 0.81 & I 2M  < 0.03 in total samples; the highest Acc 86.1% (80.6%- 90.6%), Bayes PTP 87.2% (95%CI, 81.7%- 91.4%) and Sp 87.8% (95%CI, 78.2%- 94.3%) were by I 2M  < 0.01 in males, Acc of Haavikko Ac and Demirjian H stage in second molar is very close with slightly lower Bayes PTP and Sp. I 3M is a good classifier for 16-year-old threshold (AUC = 0.889). The cut-off value I 3M  < 0.34 can be used to classify the 16-year-old threshold with Acc of 80.6% (95%CI, 77.2%-83.7%), Sp of 83.4% (95%CI, 79.0%-87.3%), and 81.7% (95%CI, 78.4%-84.8%) Bayes PTP. In conclusion, to classify the 14-year-old threshold, a pair of cut-off values I 3M  < 0.81 & I 2M  < 0.03 can be used in Croatian females; I 2M  < 0.01, Demirjian H stage, Haavikko Ac stage in second molar, and the pair I 3M  < 0.81 & I 2M  < 0.03 can all be used in Croatian males. I 3M  < 0.34 can classify the 16-year-old threshold in Croatian populations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Dental age assessment based on evaluating dental mineralization status is one of the most common methods used in forensic practice. The aim of this study is to enhance the accuracy of age diagnostics and provide reference data from the Syrian population for forensic application. After several selection steps, a total of 280 orthopantomograms (OPGs) from 140 males and 140 females from the Syrian population divided into 14 age groups between 12 and 25 years were analysed. Based on Demirjian's classification system, the mineralization stages of third molars (18, 28, 38 and 48) as well as lower second molars (37 and 47) were evaluated. Statistical investigations and evaluations were carried out to estimate the marginal probabilities of the subjects having attained ages 14 and 18 by generalized estimating equation models. Our results show that no significant differences can be revealed in the mineralization status with respect to jaw side and sex. In the Syrian population, third molars showing mineralization stage G provide evidence of reaching the age of 14 years with the highest standard of proof ("beyond reasonable doubt"). A completed mineralization in lower second molars (stage H) provides very high marginal probabilities (more than 90%) of the subjects having attained age 14 years. Nevertheless, this cannot exclude an age under 14 years. For the age threshold of 18 years, third molars showing incomplete root development (G dental stage or lower) are associated with a low probability (less than 40%) of the subject having reached 18 years of age. A person's probability of having attained 18 years of age is very high (82- 95%) when the roots of third molars are fully developed (stage H). Nevertheless, third molars at stage H do not conclusively exclude an age under 18 years., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: Molar crown configuration plays an important role in systematics, and functional and comparative morphology. In particular, the number of cusps on primate molars is often used to identify fossil species and infer their phylogenetic relationships. However, this variability deserves renewed consideration as a number of studies now highlight important developmental mechanisms that may be responsible for the presence of molar cusps in some mammalian taxa. Experimental studies of rodent molars suggest that cusps form under a morphodynamic, patterning cascade model of development (PCM) that involve the iterative formation of enamel knots. This model posits that the size, shape and location of the first-forming cusps determines the presence and positioning of later-forming cusps., Design: Here we test whether variation in accessory cusp presence in 13 Macaca fascicularis mandibular second molars (M2s) is consistent with predictions of the PCM. Using micro-CT, we imaged these M2s and employed geometric morphometrics to examine whether shape variation in the enamel-dentine junction (EDJ) correlates with accessory cusp presence., Results: We find that accessory cusp patterning in macaque M2s is broadly consistent with the PCM. Molars with accessory cusps were larger in size and possessed shorter relative cusp heights compared to molars without accessory cusps. Peripheral cusp formation was also associated with more centrally positioned primary cusps, as predicted by the PCM., Conclusions: While these results demonstrate that a patterning cascade model is broadly appropriate for interpreting cusp variation in Macaca fascicularis molars, it does not explain all manifestations of accessory cusp expression in this sample., Competing Interests: Declaration of Competing Interest The authors have no competing interest to disclose., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: To compare the mandibular posterior space available before treatment and the distance of molar distalization achieved after mandibular dentition distalization with microimplants., Materials and Methods: A total of 66 Class I or III adult patients (mean age = 24.46 ± 4.89 years) who underwent molar distalization using microimplants were retrospectively included. The posterior space available distal to the second molar before treatment and the distance of distalization achieved after treatment were measured using axial cone-beam computed tomography images (0, 2, 4, and 6 mm apical to the second molar root furcation). Changes in lingual cortical thickness and molar root length after treatment were examined. Paired t-test or Wilcoxon signed-rank test was performed to compare measurements before and after treatment. Spearman correlation analysis was performed to assess the relationship between thinning of the cortical plate and root resorption., Results: Achieved distalization distance was significantly greater than pretreatment posterior space available by 0.8 mm at all root levels (P < .001). The difference was greater toward the root apex level and greater in the Class III group than the Class I group. Lingual cortical thickness was significantly decreased after treatment along with resorption of the second molar distal root (P < .001). In addition, a positive correlation was found between thinning of the cortical plate and distal root resorption of the molar (P < .001)., Conclusions: Achieved distalization distance of the mandibular molar using microimplants was greater than the pretreatment posterior space available. Thinning of the lingual cortex and root resorption were observed after distalization., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Pursuing a proficient age estimation methodology introducing novel radiographic methods remains an ongoing and demanding aspect of forensic and medicolegal research. In 2017, Roberts GJ et al. (J Forensic Sci 62(2):351-4, 2017) described a new radiographic method, i.e., root canal width (RCW) patterns to assign a subject to above 18-year-age threshold. Since then, few researchers have investigated the validity of this radiographic method in other populations. The present study aimed to test the usefulness of these RCW patterns in predicting 18 years in a sample of South Indian juveniles and sub-adults aged between 16 and 23. Descriptive analysis revealed that pattern-A was initially observed at a minimum age of 16.08 and 16.22 years in males and females. Pattern-B at 16.31 years in males and 16.22 years in females, while pattern-C was initially recorded at 18.73 years in males and 19.01 years in females, respectively. In summary, if an individual, regardless of sex, exhibits a fully-formed (apex closed) mandibular first, second, and third molars and concurrently displays RCW-C, there is a strong likelihood that the person has exceeded the legally relevant age of 18 years. However, due to higher rate of technically unacceptable errors (adults wrongly identified as individuals below 18 years), reliance on this method alone should be restricted, and it is advisable to combine it with other methods., (© 2024. The Author(s).)