Search

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).)

Objectives: To find radiographic association of the root pulp visibility and periodontal ligament visibility stages of lower second molar teeth with chronological age., Methods: The prospective, analytical, cross-sectional study was conducted after approval from the ethics review committee of Ziauddin University, Karachi, and comprised digital orthopantomograms from 2020 to 2022. The orthopantomograms related to lower second molar teeth from the left side of the mandible of individuals of either gender aged 18-40 years. The orthopantomograms were subjected to stage classification to assess the radiographic root pulp visibility and periodontal ligament visibility of the lower second molar teeth. Data was analysed using SPSS 25., Results: Of the 260 orthopantomograms, 140(53.8%) belonged to female subjects and 120(46.2%) to male. The overall median age of the subjects was 24 years (interquartile range: 7 years). There were 164(63.1%) subjects aged 18-25 years, 70(26.9%) aged 26-33 years, and 26(10%) aged 34-40 years. A positive correlation was noted between age and stages of radiographic root pulp visibility and periodontal ligament visibility (p<0.05). The individuals found at stages 0 and 1 for root pulp visibility were aged at least 18 years, and for stage 2, the corresponding value was 21 years. For periodontal ligament visibility, the minimum age for stage 0 was 18 years, while for stages 1 and 2, the corresponding values were 21 and 25 years., Conclusions: Lower age was found to be associated more with stage 0 of root pulp visibility and periodontal ligament visibility.

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.)

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.)

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.)

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).)

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: 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.)

Objective The objective of this study was to measure and analyze the joint space, condylar morphology, and thickness of the roof of the glenoid fossa (RGF) in patients with unilateral second molar scissor bite using cone beam CT (CBCT). Methods A total of 80 patients were included in this study. Forty patients with a normal posterior occlusal relationship, who attended the Department of Orthodontics at the First Hospital of Shanxi Medical University from December 2021 to August 2023, were selected as the control group. The experimental group consisted of 40 patients with unilateral second molar scissor bite during the same period. All patients underwent CBCT scanning, and the resulting images were analyzed using the NNT viewer software in multiplanar reconstruction (MPR). Axial, coronal, and sagittal adjustments were made for each patient. Results In the control group, the right and left joint spaces (PS, SS, AS), the height of the upper part of the condyle, and the depth of the glenoid fossa did not show statistically significant differences (P > 0.05). When comparing bilateral condylar morphology and joint space in the experimental group, it was found that the posterior joint space on the scissor bite side was greater than that on the normal occlusion side, while the anterior joint space on the scissor bite side was smaller than that on the normal occlusal side. Additionally, the height of the upper condyle and the depth of the glenoid fossa on the scissor bite side were greater than that on the normal occlusal side, with statistically significant differences (P < 0.05). However, there were no statistically significant differences in SS, internal and external joint diameter, as well as anterior and posterior diameters (P > 0.05). The comparison of the minimum thickness of the roof of the glenoid fossa in both the sagittal and coronal directions between the patients in the experimental group and the control group showed no statistically significant difference (P > 0.05). Furthermore, the asymmetry index of the supracondylar height in the control group was significantly smaller than that in the experimental group, displaying a statistically significant difference (P < 0.05). The differences in the asymmetry indices of the anterior and posterior diameters of the condyle, as well as the inner and outer diameters, were not statistically significant (P > 0.05). When analyzing the position of the condyle in the sagittal direction of the glenoid fossa in the patients of the control group, it was observed that the majority were in the anterior and medial positions, with only 10% and 5% being in the posterior position. However, the analysis of the condyle position in the sagittal direction of the glenoid fossa in the experimental group revealed statistically significant differences (P < 0.05), with the condyle position on the scissor bite side being more anterior. Conclusion Unilateral second molar scissor bite can result in anterior displacement of the condyle, greater height of the condyle superiorly as well as the depth of the glenoid fossa., (© 2024. The Author(s).)

Objectives: The purpose of this multicenter retrospective study was to perform a two-dimensional analysis of upper airway changes in adolescent patients following molar distalization with the Pendulum appliance., Materials and Methods: The study involved the cephalometric analysis of 88 patients, retrospectively categorized into two groups: skeletal Class II with a dental Class II molar relationship (36 patients, mean age 12.6 ± 1.1 years) and skeletal Class I with a dental Class II molar relationship (54 patients, mean age 12.3 ± 1.2 years). Changes were observed using lateral radiographs before (T0) and after Pendulum appliance removal (T1); treatment time averaged 7 months. Upper airways were subsequently analyzed by tracing lateral radiographs. The Shapiro-Wilk test showed a normal distribution of the data, therefore parametric tests were used for statistical analysis. Intragroup changes between T0 and T1 were evaluated using paired t-tests, and intergroup differences were assessed using independent student t-tests; statistical significance was set at 0.05., Results: Statistically significant differences were observed in the skeletal measurements that characterized both groups, particularly in ANB and Wits appraisal, at T0 (P < 0.001). After molar distalization, Class I and Class II groups reported no statistically significant differences with changes almost equal to zero between timepoints (P > 0.05). Additionally, intergroup comparisons of airway changes at T1 did not show statistically significant differences (P > 0.05)., Conclusions: The Pendulum appliance does not significantly change the upper airway dimensions in Class I and Class II malocclusion patients, thereby minimizing potential respiratory risks., (© 2024. The Author(s).)

Purpose: The aim of this study was to investigate the accessory root canal morphology of maxillary first molars in a Black South African subpopulation., Methods: Micro-computed tomography was used to investigate 101 maxillary first molars (from 50 male and 51 female teeth, right 53 teeth, left 48 teeth). The prevalence of chamber canals, and the number, type and location (root third) of accessory canals were recorded. The relationships between arch side, sex and age were examined using chi-squared tests of association. Intra- and inter-observer reliability were assessed using Cohen's kappa test., Results: Intra- and inter-rater agreement was 96.9% and 98.1%, respectively. Variations in accessory root canal anatomy according to side, sex and age were evident. Chamber canals were identified in 10.9% of teeth. Accessory canals were found mainly in the apical third of most teeth in the sample, and distributed predominantly in the mesio-buccal root. Apical deltas were most prevalent in the mesio-buccal root, and their frequency decreased in the palatal and then finally the disto-buccal root., Conclusion: Accessory root canals were common in this population, and showed a diverse range of anatomy. The present findings will be of assistance to clinicians during endodontic treatment and will also be valuable for educational purposes.

Background: Mandibular second molar (M2M) impaction is a clinically significant manifestation of eruption disturbance in dental development. The primary aim of this study was to investigate the impact of the three-dimensional (3D) characterization on clinical and therapeutic decisions for M2M impaction. The secondary aim was to introduce a validated 3D classification system incorporating both surgical and orthodontic parameters., Methods: Bidimensional (2D) and 3D radiological records of 15 impacted M2M were collected and deidentified. Ten experienced clinicians (5 oral surgeons;5 orthodontists) categorized each case, first based on 2D records and then with 3D scans. The degree of orthodontic and surgical difficulty in treating impacted M2M was evaluated using a novel classification system based on anatomical and radiological features. The primary outcome variable was the assessment of differences in diagnosis and decision-making protocol using 2D or 3D records, where clinical relevance ranged from 0 to 4. The secondary outcome variable was the validation analysis of the proposed 3D classification system to determine the concordance among the clinicians. Descriptive statistics and multivariable inferential analysis based on Akaike information criterion (AIC) were performed (α = 0.05)., Results: 3D examination allowed a better visualization of M2M impaction with higher clinical relevance for diagnosis of M2M root relationship to alveolar nerve and lingual plate, height to alveolar crest, depth, and inclination relative to the first molar and position relative to the third molar (range:2.69-3.43). The proposed 3D classification of M2M impaction changed clinical decisions regarding surgical-orthodontic approach, biomechanics, patient education, and treatment time estimate (range:2.59-3.33). In the validation analysis of the classification, no evidence of inter- or intra-group (surgeon/orthodontist) bias in score attribution occurred: the model with the minimum AIC was the null model (AIC = 718.04)., Conclusion: 3D evaluation of impacted M2Ms could enhance diagnostic accuracy, and a classification system was proposed and validated by a group of experienced surgeons and orthodontists with high concordance., (© 2024. The Author(s).)

Background: In clinical practice, the buccal approach is typically the primary choice for endodontic microsurgery. Owing to the thickness of the buccal bone plate, the distance between the buccal bone plate and palatal lesion location, and soft tissue traction, the palatal approach may be more suitable for microsurgery for apical periodontitis of the palatal roots of the maxillary molars. However, the length of the palatal root, location of the greater palatine artery (GPA) and foramen (GPF), and surgical field of observation make palatal surgery challenging., Case Presentation: With the aid of Cone-beam computed tomography imaging, the palatal approach was successfully applied in nine cases of endodontic microsurgery of the palatal root of a maxillary molar with a periapical lesion in Hangzhou Stomatology Hospital from January to December 2022., Conclusions: Complete healing was assessed based on clinical symptoms and radiographic images at the 3- and 24-month follow-up visits in all nine cases. Several tips have been proposed including surgical positioning, incision design, palate flap modification, bone removal, and root-end resection., (© 2024. The Author(s).)

Background: This study aimed to investigate the differences in the buccolingual inclination and transverse width of maxillary and mandibular first molars among different vertical facial types., Methods: In all, 78 samples were divided into three groups based on the GoGn-SN angle: the low-angle group (n = 26, mean age=24.21±5.11), average-angle group (n = 26, mean age=22.66±3.72), and high-angle group (n = 26, mean age=22.23±2.43). Cone beam computed tomography (CBCT) measurements were used to assess the buccolingual inclination of the axis of the maxillary and mandibular first molars, as well as the buccolingual inclination of the alveolar bone, the dental arch width, and the basal bone width. One-way ANOVA, the LSD test, and Pearson correlation analysis were performed., Results: The high-angle group showed significantly greater lingual inclination of the maxillary alveolar bone than the low-angle group and average-angle group (p < 0.001; p < 0.05). The difference in buccolingual inclination of the axis of the maxillary first molar and the alveolar bone was significantly greater in the high-angle group than in the low-angle group (p < 0.05). Both the maxillary and mandibular dental arch were significantly narrower in the high-angle group than in the other two groups. The mandibular basal bone was also significantly narrower in the high-angle group than in the low-angle group and average-angle group (p < 0.001; p < 0.01)., Conclusions: The alveolar bone of maxillary first molar in the high-angle group was more palatal inclined than that the low-angle group and the average-angle group, which suggests that orthodontists should pay more attention to the root-bone relationship in the high-angle group during expansion treatment to prevent bone fenestration and dehiscense., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Temporary anchorage devices (TADs) are frequently applied to different anatomic areas with different protocols to increase skeletal effects and anchorage in orthodontic treatment planning. It has been reported in many literatures that primary stability for orthodontic TADs is significant for long-term survival rate. For this reason, different areas of the palatal region, which has many indications, have been widely used in the studies. In this evaluation where bone quality and thickness are important, density, bone thickness, and fractal dimension (FD) on cone beam computed tomography (CBCT) will provide more predictable clinical results. The aim of this study was to evaluate bone thickness, density, and FD in the palatal region of the first, and second premolars, and first molars. There was a remarkable difference (p < 0.05) between the parameters of FD, thickness and density of bone in the identified areas in the palatal region. In terms of thickness and FD, the 1st premolar region had significantly higher values than the other regions (p < 0.05). In terms of density, the values in the right 1st molar and right 1st premolar regions were significantly higher (p < 0.05). The 1st premolar region is an ideal site for placement of palatal TADs. CBCT-assisted preliminary evaluation of FD value, bone density, and thickness may increase clinical success when selecting the location of TADs to be applied to the palatal bone., (© 2024. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

Objectives: This study aimed to assess the accuracy of ultra-low dose (ULD) cone-beam CT (CBCT) for detection of proximal caries., Methods: This in vitro study evaluated 104 molar and premolar teeth. The teeth were mounted in dry skulls and underwent CBCT with 4 protocols of high-resolution (HR), normal (NORM), ULD-HR, and ULD-NORM; 78 CBCT images were scored by 3 observers for the presence and penetration depth of caries twice with a 2-week interval using a 5-point Likert scale. The teeth were then sectioned and observed under a stereomicroscope (gold standard). The 4 protocols were compared with each other and with the gold standard. The receiver operating characteristic curve was drawn, and the area under the curve (AUC) was calculated and compared by the Chi-square test (alpha = .05)., Results: The interobserver agreement ranged from 0.5233 to 0.6034 for ULD-NORM, 0.5380 to 0.6279 for NORM, 0.5856 to 0.6300 for ULD-HR, and 0.6614 to 0.7707 for HR images. The intra-observer agreement ranged from 0.6027 to 0.8812 for ULD-HR, 0.7083 to 0.7556 for HR, 0.6076 to 0.9452 for ULD-NORM, and 0.7012 to 0.9221 for NORM images. Comparison of AUC revealed no significant difference between NORM and ULD-NORM (P > .05), or HR and ULD-HR (P > .05). The highest AUC belonged to HR (0.8529) and the lowest to NORM (0.7774)., Conclusions: Considering the significant reduction in radiation dose in ULD CBCT and its acceptable diagnostic accuracy for detection of proximal caries, this protocol may be used for detection of proximal carious lesions and assessment of their depth., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology and the International Association of Dentomaxillofacial Radiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Introduction: This prospective study evaluated the effect of immediate functional loading (IFL) of a full-coverage prosthesis on the clinical and radiographic outcome of nonsurgical endodontic therapy (NSET) performed on mandibular molar teeth with pulp necrosis and asymptomatic apical periodontitis., Methods: In 20 subjects, standardized 2-visit NSET was performed in bilateral mandibular first molar teeth (split-mouth model) with a diagnosis of pulp necrosis and asymptomatic apical periodontitis exhibiting a radiographic periapical index (PAI) score ≥3. In each subject, the nonvital bilateral mandibular first molar teeth were randomized to 1 of 2 groups: the IFL group or the functional loading after a time interval of 6 months group. Provisional full-coverage prostheses were provided within 7 days after the completion of endodontic therapy. The cases were followed up clinically and radiographically at 6 and 12 months. Radiographs were assessed for periapical healing based on PAI scores, which were dichotomized as healed (PAI score ≤2) or nonhealed (PAI score ≥3). The data were compared using chi-square and Fisher exact tests., Results: A recall rate of 100% was achieved at the end of 12 months. All teeth in the IFL group and the functional loading after a time interval of 6 months group were clinically asymptomatic. According to an intergroup comparison between the proportion of teeth healed and nonhealed (radiographic), there was a significant difference (P < .05)., Conclusions: IFL of a full-coverage prosthesis in endodontically treated mandibular molar teeth with pulp necrosis and asymptomatic apical periodontitis delayed periapical healing., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: This retrospective single-centre study aimed to compare the efficacy of maxillary second molar intrusion with two different approaches, miniscrew-assisted molar intrusion and traditional segmental archwire intrusion, and to compare orthodontically induced external apical root resorption (OIERR) during intrusion between two groups via cone beam computed tomography (CBCT)., Materials and Methods: A total of 40 adult patients (33.6 ± 10.3 years old) with supraerupted maxillary second molars due to the loss of antagonistic teeth were recruited, with 20 patients in each group. A segmental archwire with adjacent teeth as an anchorage was used in the control group, and 60-100 g of intrusive force was applied by using miniscrews in the experimental group to intrude the overerupted molars. Full-volume CBCT was performed before and after intrusion, and the amount of intrusion and extent of OIERR of the overerupted molars were compared between the two groups., Results: Supraerupted maxillary second molars could be successfully intruded in an average of 5 months. There was more intrusive movement of the buccal and palatal cusps in the mininscrew group than that in the segmental archwire group (P < .05). The intrusive amount of palatal cusp was 3.67 ± 1.13 mm in the miniscrew group and 2.38 ± 0.74 mm in the segmental archwire group. More palatal OIERR was observed in the miniscrew group (30.3 ± 11.6 mm 3 ) than in the segmental archwire group (21.0 ± 8.66 mm 3 ) (P = .0063). There was no significant difference in OIERR between the two groups for mesial and distal buccal roots (P > .05)., Conclusion: Miniscrews help effectively with supraerupted maxillary second molar intrusion, especially for palatal cusps. There was more OIERR in the palatal root when using miniscrews compared to the segmental archwire approach., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: To evaluate the trueness of dental arches digitised by two intraoral scanning (IOS) technologies from patients presenting crowding, diastema, and bilateral posterior edentulous space with tilted molar., Methods: Conventional impressions and dental stone models were generated from three patients presenting the aforementioned dental arch conditions. These models were digitised on a desktop scanner, and the resulting mesh was used as reference. Subsequently, the patients were scanned using confocal based (CF; iTero Element 2) and blue laser-multiscan (BLM; Virtuo Vivo) imaging IOS technology, totalling thirty scans. The meshes from the scans were exported in Standard Tessellation Language format and analysed using Geomagic Control X software. Root mean square (RMS) indicated deviation magnitude. Differences in IOS technologies were evaluated with paired t-tests, and dental arch conditions compared using ANOVA and post-hoc Tukey tests (α=0.05)., Results: Digital dental arch from blue laser-multiscan technology showed lower trueness compared to confocal based technology for crowding (p = 0.0084) and edentulous spaces (p = 0.0025) conditions. When the types of oral condition were compared, discrepancies were significantly different for both IOS technologies, featuring the arch with diastema showing the lowest trueness, followed by edentulous spaces and crowding., Conclusion: Dental arches presenting crowding and edentulous spaces digitised by blue laser-multiscan technology exhibited greater discrepancies compared to confocal based imaging technology. Furthermore, trueness varied among the dental arch conditions., Clinical Significance: The IOS technology and patient's dental arch condition can influence the trueness of dental arch digitisation. Being aware of these effects allows clinicians to take them into account during scanning procedures, digital planning and manufacturing., 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.)

Introduction and Aims: Violations of the mandibular canal (MC) and mental foramen (MF) and subsequent injuries to their neurovascular bundle have been reported after surgical and nonsurgical dental procedures. Besides using advanced technologies such as cone-beam computed tomography (CBCT), clinicians should be aware of the anatomy and location of MC and MF in different populations. This study aims to describe the morphologic characteristics of the MF, MC, and its intrabony location in relation to the apices of mandibular posterior teeth in an Emirati subpopulation using CBCT., Methods: A total of 3700 CBCT scans were screened, and 154 scans that met the inclusion and exclusion criteria were randomly selected. The scans were assessed using 3-dimensional multiplanar imaging for the following structures: the location of MF and the MC course, its intrabony location, and its relationship to the apices of the mandibular posterior teeth. The data were analysed statistically using SPSS software., Results: The MC ran lingually and inferiorly at the posterior region and became more buccal and superior towards the MF. The distal root of the mandibular second molar was found to be the closest root to the MC (2.06 ± 1.83 mm). Moreover, the most common location of the MF was distal to the contact area between the 2 premolars (0.83 ± 1.84 mm) with a significant negative correlation to age (with and increase in age, the MF moves distally). The distance between the root apices and the MC was statistically significantly affected by age (positive correlation) and gender (male patients had a greater distance)., Conclusions: The common course of the MC is lingual and inferior posteriorly and becomes more buccal and superior towards the MF, which is located mostly between the mandibular first and second premolars. Furthermore, the distal root of the mandibular second molar is the closest to the MC and has a positive relationship with age., Competing Interests: Conflict of interest None disclosed., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: The aim of this study was to evaluate the volume of dentin removal and the volume of remnants of restorative material after the removal of an esthetic restorative coronal set and cervical barrier in endodontically treated mandibular molars with the aid of different magnification methods using 3-dimensional (3D) micro-computed tomographic (micro-CT) morphometric analysis., Methods: A sample of 30 mandibular first molars (N = 30) was used. All teeth were endodontically treated, and the specimens were initially scanned using micro-CT imaging and reconstructed. The molars were filled by a single-cone technique, and immediately the material at the initial 2-mm cervical level was removed. Cervical barriers were confected using ionomer glass cement with fluorescein 0.1%, filling the 2 mm at the cervical level of the canals and an additional 2 mm as the base. The coronal restoration set was performed using esthetic resin composites. A simulated tooth aging process was performed with 20,000 thermocycling cycles. The sample was distributed into the following 3 groups (n = 10) for the removal of the restoration set and cervical barrier with diamond burs based on the magnification aid: no magnification aid (naked eye), operative microscope aid, and REVEAL device (Design for Vision Inc, Bohemia, NY) aid. After removal, the final 3D micro-CT scanning and reconstruction were conducted with the same parameters as the initial scanning, and superposition of the final and initial scanning was performed. Morphometric analysis was conducted using CTAn software (Bruker microCT, Kontich, Belgium) to assess the volume of remnant restorative material (mm³), the volume of dentin removal (mm³), and the direction and site of dentin removal. Data were analyzed using 1-Way analysis of variance (P < .05)., Results: The REVEAL group showed better results regarding the volume of remnant material (3.17 ± 1.65) and the percentage of dentin removal (2.56 ± 1.34). The microscope group showed no statistical difference compared with the REVEAL group regarding dentin removal (3.30 ± 1.48) and was statistically similar to the naked eye group in the volume of remnant material (9.63 ± 4.33). The naked eye group showed the worst results for the volume of remnant material (7.60 ± 2.68) and the percentage of dentin removal (6.60 ± 3.70)., Conclusions: The use of fluorescence associated with magnification was the method that presented the best results, with lower percentages of dentin removal and smaller volumes of remaining restorative material. This is an innovative technology in endodontics that shows potential to overcome the challenge of reaccessing root canals in the context of endodontic retreatment., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Background: To investigate the anatomic features of the root furcation of permanent mandibular first molars., Methods: A total of 50 extracted mandibular first molars (25 two-rooted and 25 three-rooted) were collected and scanned using micro-computed tomography. The digital models of teeth and root canal systems were reconstructed three-dimensionally. The tooth models were displayed in parallel projection mode from buccal and distal views. Screenshots were captured and subsequently analyzed using Image-Pro Plus 6.0 software after calibration. The furcation angle, root trunk length, maximum depth and level of distal root concaves of mesial roots, and length of enamel projections were measured, and the furcation types (classified into type V, type U and type W) were detected. Statistical analysis was performed using the Shapiro-Wilk's test, one-way analysis of variance, Student's t-test and Chi-square test., Results: The mean furcation angle between the distobuccal (DB) and distolingual (DL) roots (in distal view) was the greatest (59.2°), whereas the furcation angle between the mesial and DL roots (in buccal view) was the smallest (25.4°) among the four furcation angles (all p < 0.05). Regarding the furcation types, bucco-lingual root trunk length, maximum depth and site of the distal root concavities, and enamel projection length, no significant differences were detected between the three- and two-rooted molar groups (all p > 0.05). The frequency of type V was the highest (54.0%), followed by type U (26.0%), and type W had the lowest occurrence rate (20.0%). The mean length of distal root trunk in the three-rooted mandibular molars was significantly greater than that of the buccal/lingual one (3.7 mm vs. 3.0 mm, p < 0.01). The maximum depth of the distal concavities of the mesial roots was on average 0.66 ± 0.19 mm, and the site was located at an average of 2.8 ± 1.3 mm below furcation. The mean length of buccal enamel projections was significantly longer than that of lingual ones (3.1 mm vs. 0.7 mm, p < 0.01)., Conclusions: The furcation anatomy of the mandibular first molar is complex, and the presence of the DL root may further complicate its topography. A thorough understanding of these anatomic features is essential for successful periodontal treatment., (© 2024. The Author(s).)

Background: This investigation compared the extent of external apical root resorption (EARR) in root-filled teeth (RFT) and their contralateral vital pulp teeth (VPT) counterparts during orthodontic treatment (OT) with clear aligner (CA) treatment or fixed appliance (FA) treatment., Methods: Sixty-six patients with similar baseline American Board of Orthodontics (ABO) discrepancy index scores were divided into two groups: 37 patients (21 females, 16 males; mean age 17.45 ± 2.67 years) in the FA group, and 29 patients (18 females, 11 males; mean age 18.33 ± 1.96 years) in the CA group. Digital panoramic radiographs captured pre- and post-OT were used to measure tooth lengths and root surface measurements in mandibular molars. EARR in both RFT and contralateral VPT was evaluated pre- and post-OT. Statistical analysis employed paired t-tests, independent t-tests, and analysis of covariance (ANCOVA) (p < .05)., Results: All teeth exhibited varying degrees of EARR following OT. FA treatment resulted in significantly longer treatment duration (p < .05) and greater EARR compared to CA treatment (p < .05). Moreover, statistically significant differences in EARR were observed within both groups between RFT and VPT (p < .05)., Conclusions: Comparison of pre- and post-OT radiographs revealed different degrees of EARR in all teeth. CA treatment resulted in less frequent and less severe EARR compared to FA treatment. RFT demonstrated greater resistance to EARR than VPT in both treatment groups., (© 2024. The Author(s).)

This study employed e-Vol DXS cone beam computed tomography (CBCT) software to assess dentin remnants in the furcation area of mesial canals in mandibular molars during root canal retreatment (RCR). Four groups (Reciproc®, ProTaper Next®, Race Evo®, Protaper Gold®) were subjected to RCR, and CBCT images were captured before (T1) and after (T2) treatment. Measurements of remaining dentin thickness at 1 mm and 3 mm below the furcation were scrutinized. Results revealed no significant differences in mean thicknesses of mesiobuccal (MB) and mesiolingual (ML) canals at 1 mm and 3 mm from the furcation pre-treatment (T1). Post-treatment (T2) showed analogous findings, with no significant differences in mean thicknesses. However, disparities were found between MB and ML canals at both distances, both before and after retreatment. In essence, the evaluated instruments exhibited safety in RCR, implying that they are appropriate for use in critical areas of mandibular molars without inducing excessive wear. This study underscores the reliability of these instruments in navigating danger zones during RCR, and contributes valuable insights for dental practitioners who handle complex root canal scenarios in mandibular molars.

Aim: To investigate the root number and morphology of the maxillary second molars in the Syrian population besides bilateral symmetry, and the effect of gender., Methods: 250 Cone Beam Computed Tomography (CBCT) images (140 females, 110 males) were examined by two endodontists. The detailed analysis included the number of roots, the number of canals and their configurations, bilateral symmetry, and relation to gender. The evaluation was made according to Vertucci classification by analyzing the CBCT images at all levels (Axial, Coronal, Sagittal, Oblique, and 3D). The Chi-square statistical analysis was performed to compare the canals' morphologies and bilateral symmetry in both genders via SPSS., Result: The most common shape of the upper second molars is three roots (90.4%). There were significant differences between males and females regarding the symmetry of the number of roots (P < 0.05). The root canal configuration was mainly Vertucci type I classification in the Distobuccally (93.4%) and palatal root (99.6%). The most common type in the mesial root was type I (29.5%), showing all varieties of Vertucci classifications (except VII, and VIII) percentage of MB2 of 70.5%. The ratio of symmetry was (59.6%) with no significant statistical difference between the genders (P = 0.708)., Conclusion: Most maxillary second molars in the examined Syrian population were types (II) (associated with MB2 cases with three roots and four canals). In terms of symmetry, the number of roots surpassed the canal configuration. Males had a greater symmetrical tendency in the number of roots than females., (© 2024. The Author(s).)

The accomplishment of a successful pulpectomy depends on multiple factors that involve targeted removal of the causative irritants and soft and hard tissue debris by mechanical and chemical means. Compare and evaluate the efficacy of canal preparation and volumetric filling using conventional files and two rotary file systems using cone beam computed tomography (CBCT). Thirty freshly extracted human primary second molars were randomly divided into three groups of 10 teeth each. After access opening and working length determination, pre-operative volume analysis was done using CBCT. The canals were then instrumented by either hand K-files, ProTaper rotary files or Kedo-SG Blue rotary files. Post-operative volume analysis was performed using CBCT. All the canals were obturated using Metapex and scanned again using CBCT. Mean values of the pre- and post-operative canal volumes were analyzed using one-way Analysis of Variance (ANOVA). Inter- and intra-group volumetric changes were analyzed statistically using a post hoc test. The mean difference in volume after canal preparation and obturation was the highest in the Kedo-SG Blue group, followed by the ProTaper group and the least in the hand K group ( p = 0.001). Inter-group comparison showed statistically significant differences between the hand K group and ProTaper group ( p = 0.001), the ProTaper group and Kedo-SG Blue group ( p = 0.001), and the hand-K group and Kedo-SG Blue group ( p = 0.02). The volume of preparation and obturation was the highest using Kedo-SG Blue, followed by the ProTaper file systems., Competing Interests: The author declares no conflict of interest., (©2024 The Author(s). Published by MRE Press.)

Objectives: To assess skeletal and dental effects and evaluate possible side effects of maxillary expansion with two different appliances, directly after expansion and 1 year postexpansion., Materials and Methods: Forty-two patients with unilateral posterior crossbite (mean 9.5 ± 0.9 years) were randomized to either rapid maxillary expansion (RME) banded on the deciduous second molars and bonded to the primary canines or slow expansion with quad helix (QH) on the permanent first molars. Cone-beam computed tomography records were taken at baseline, directly after correction of the posterior crossbite and at follow-up 1 year after expansion., Results: All patients were analyzed. RME opened the midpalatal suture more anteriorly and inferiorly (mean 4.1 mm) and less posteriorly and superiorly (mean 1.0 mm). No effect on midpalatal suture could be shown in the QH group after expansion, P < .001. Buccal bone width had significantly decreased (P < .001) in the QH group compared with the RME group. Buccal fenestrations and root resorption on the left first molar had a higher prevalence directly after expansion finished in the QH group (P = .0086, P = .013) but were not significant at 1-year follow-up (P = .11, P = .22)., Conclusions: Opening of the suture with RME was more anterior and inferior, and the QH did not open the midpalatal suture at all. More buccal bone loss and fenestrations were seen on the permanent first molar in patients treated with conventional QH than RME anchored to deciduous teeth., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Introduction: To evaluate the prevalence of single root with a single root canal and four-root configurations in the maxillary first and second molars, and analyze how geographic region, ethnicity, sex, and age impact these outcomes., Methods: Researchers from 44 nations examined 26,400 maxillary molars using cone-beam computed tomography scans to gather data on the proportions of single roots with single canals and four-root configurations. All observers underwent prior calibration regarding the step-by-step assessment protocol and anatomical concepts to ensure consistent evaluations across all assessed locations. Tests were conducted to evaluate the intraobserver and interobserver reliability. Demographic data including ethnicity, gender, and age were collected for each participant. The potential impact of imaging voxel size and field-of-view on bias was also assessed. The primary results were depicted as odds ratios and untransformed proportion forest plots with 95% confidence intervals. Additionally, a meta-analysis was performed to compare various subgroups and identify sources of variation among them. Statistical significance was set at 5%., Results: The prevalence of single-rooted with a single canal and four-rooted configurations in the maxillary first molar was 0.16% and 0.28%, respectively, while in the maxillary second molar, it was 2.56% and 0.83%. Males tended to exhibit lower percentages of single roots with a single canal (P < .05) and higher percentages of four-rooted configurations (P > .05) in the second molar, whereas the African subgroup displayed lower proportions for both configurations. Additionally, in both teeth, single roots with a single canal were more prevalent among older patients. Voxel size and field-of-view did not significantly influence the results (P > .05)., Conclusions: The proportions of single-rooted with a single canal and four-rooted configurations were low, and demographic factors such as geographic region, ethnicity, sex, and age may have influenced the outcomes for the maxillary second molar., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: In dental clinical practice, cone-beam computed tomography (CBCT) is commonly used to assist practitioners to recognize the complex morphology of root canal systems; however, because of its resolution limitations, certain small anatomical structures still cannot be accurately recognized on CBCT. The purpose of this study was to perform image super-resolution (SR) processing on CBCT images of extracted human teeth with the help of a deep learning model, and to compare the differences among CBCT, super-resolution computed tomography (SRCT), and micro-computed tomography (Micro-CT) images through three-dimensional reconstruction., Methods: The deep learning model (Basicvsr++) was selected and modified. The dataset consisted of 171 extracted teeth that met inclusion criteria, with 40 maxillary first molars as the training set and 40 maxillary first molars as well as 91 teeth from other tooth positions as the external test set. The corresponding CBCT, SRCT, and Micro-CT images of each tooth in test sets were reconstructed using Mimics Research 17.0, and the root canal recognition rates in the 3 groups were recorded. The following parameters were measured: volume of hard tissue (V1), volume of pulp chamber and root canal system (V2), length of visible root canals under orifice (VL-X, where X represents the specific root canal), and intersection angle between coronal axis of canal and long axis of tooth (∠X, where X represents the specific root canal). Data were statistically analyzed between CBCT and SRCT images using paired sample t-test and Wilcoxon test analysis, with the measurement from Micro-CT images as the gold standard., Results: Images from all tested teeth were successfully processed with the SR program. In 4-canal maxillary first molar, identification of MB2 was 72% (18/25) in CBCT group, 92% (23/25) in SRCT group, and 100% (25/25) in Micro-CT group. The difference of hard tissue volume between SRCT and Micro-CT was significantly smaller than that between CBCT and Micro-CT in all tested teeth except 4-canal mandibular first molar (P < .05). Similar results were obtained in volume of pulp chamber and root canal system in all tested teeth (P < .05). As for length of visible root canals under orifice, the difference between SRCT and Micro-CT was significantly smaller than that between CBCT and Micro-CT (P < .05) in most root canals., Conclusions: The deep learning model developed in this study helps to optimize the root canal morphology of extracted teeth in CBCT. And it may be helpful for the identification of MB2 in the maxillary first molar., (Copyright © 2024. Published by Elsevier Inc.)

Introduction: Curved mesial roots can be challenging for different stages of endodontic treatment. Preparation aims to enlarge, clean, and shape the root canal system, and hundreds of systems are available to carry it out. Aiming to maintain pericervical dentin, minimally invasive preparation was proposed, and with it, instruments with lower tapers emerged. This study aimed to evaluate the increase in canal volume, the centering ability of the instruments, and root canal transportation of two different rotary systems with lower tapers., Methods: Eighteen curved mesial roots of extracted mandibular molars were scanned by micro-CT at 3 moments: initial and after the 2 stages of endodontic preparation. The canals were prepared using TruNatomy (TN) and ProDesign Logic 2 (PDL2) instruments up to sizes 25.04 and 26.04, respectively, and after 36.03 and 35.05, respectively. The data were analyzed using parametric and nonparametric tests with a significance level of 5%., Results: TN and PDL2 systems showed no difference regarding the increase in the volume of the canals with the first instruments, but after preparation with a diameter size of 35 or 36, there was a difference (P < .01) between the systems in the cervical and middle thirds., Conclusion: Both systems shaped the mesial canals of mandibular molars while keeping low transportation and good centering ability in enlargements up to diameter size 35 or 36 with tapers of 3 or 5%., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: Maintaining effective and efficient occlusal morphology presents adaptive challenges for mammals, particularly because mastication produces interactions with foods and other materials that alters the geometry of occlusal surfaces through macrowear and/or catastrophic failure (i.e. "chipping"). Altered occlusal morphologies are often less effective for masticating materials of given diet-but not always-some species exhibit dental sculpting, meaning their dentitions are set up to harness macrowear to hone their occlusal surfaces into more effective morphologies (i.e. secondary morphologies). Here we show that dental sculpting is present in the folivorous Presbytis rubicunda of Borneo., Methods: Thirty-one undamaged lower second molars of P. rubicunda exhibiting various stages of macroscopic wear were micro-CT scanned and processed into digital surfaces. The surfaces were measured for convex Dirichlet normal energy (vDNE, a measure of surface sharpness), and degree of surface wear. Regression analyses compared surface sharpness with several measures of wear to test for the presence and magnitude of dental sculpting., Results: Positive correlations between the wear proxies and vDNE reveal that P. rubicunda wear in such a way as to become sharper, and therefore more effective chewing surfaces by exposing enamel-dentine junctions on their occlusal surfaces and then honing these junctions into sharpened edges. Compared to another primate folivore in which increasing surface sharpness with macrowear has been demonstrated (i.e., Alouatta palliata), the worn surfaces are similarly sharp, but the dental sculpting process appears to be different., Discussion: The results presented here suggest that not only do some primates exhibit dental sculpting and the attendant secondary morphology, but that there appear to be multiple different morphological configurations that can achieve this result. P. rubicunda has thicker enamel and a more stereotyped wear pattern than A. palliata, although both show positive correlations of occlusal surface sharpness (vDNE) with various wear proxies. These findings shed light on the varied approaches for the maintenance of effective and efficient occlusal surfaces in primates., (© 2024 Wiley Periodicals LLC.)

Introduction: Understanding the intricate anatomical morphology of fused-rooted mandibular second molars (MSMs) is essential for root canal treatment. The present study utilized a deep learning approach to identify the three-dimensional root canal morphology of MSMs from two-dimensional X-ray images., Methods: A total of 271 fused-rooted MSMs were included in the study. Micro-computed tomography reconstruction images and two-dimensional X-ray projection images were obtained. The ground truth of three-dimensional root canal morphology was determined through micro-computed tomography images, which were classified into merging, symmetrical, and asymmetrical types. To amplify the X-ray image dataset, traditional augmentation techniques from the python package Augmentor and a multiangle projection method were employed. Identification of root canal morphology was conducted using the pretrained VGG19, ResNet18, ResNet50, and EfficientNet-b5 on X-ray images. The classification results from convolutional neural networks (CNNs) were then compared with those performed by endodontic residents., Results: The multiangle projection augmentation method outperformed the traditional approach in all CNNs except for EfficientNet-b5. ResNet18 combined with the multiangle projection method outperformed all other combinations, with an overall accuracy of 79.25%. In specific classifications, accuracies of 81.13%, 86.79%, and 90.57% were achieved for merging, symmetrical, and asymmetrical types, respectively. Notably, CNNs surpassed endodontic residents in classification performance; the average accuracy for endodontic residents was only 60.38% (P < .05)., Conclusions: CNNs were more effective than endodontic residents in identifying the three-dimensional root canal morphology of MSMs. The result indicates that CNNs possess the capacity to employ two-dimensional images effectively in aiding three-dimensional diagnoses., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: To determine the influence of the presence/absence of third molars and intact/loss of cortical plate of the maxillary tuberosity on the amount of distal movement of the maxillary first permanent molar during distal movement of the maxillary dentition with mini-implants., Materials and Methods: Thirty six maxillary tuberosity sites were evaluated in eighteen young adult patients. The distal movement of the entire maxillary dentition was performed with mini-implants with 200 g of distalising force applied from the mini-implant placed in the maxillary posterior buccal region to attachments placed on the arch wire between the maxillary lateral incisor and canine bilaterally. The distal movement of the maxillary first permanent molars was measured on lateral cephalograms. The maxillary tuberosity sites with intact cortical plate due to congenitally missing third molars or atraumatic extraction of third molars (G1), partial loss of cortical plate due to surgical removal of third molars (G2), fully erupted third molars (G4), third molars located at (G3), and below the cementoenamel junction (G5) were evaluated with cone beam computed tomography. One way Anova and Fisher LSD test was done., Results: The order of greater to lesser amount of distal movement of the maxillary first permanent molar depending on the integrity of maxillary of tuberosity was partial loss of cortical plate, third molars at the cementoenamel junction, third molars below the cementoenamel junction, intact cortical plate and fully erupted third molars., Conclusion: The integrity of the cortical plate and the relative position of the maxillary third molar to the second molar influence the amount of distal movement of the maxillary first permanent molar during distal movement of the maxillary teeth with TADS., Clinical Relevance: The amount of distal movement of the maxillary dentition appears to depend on the presence or absence of the third molars and the condition of the cortical plate in the region of the maxillary tuberosity and thereby greatly influence the outcome of treatment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: The purpose of the study was to evaluate the proximity between the root apices of maxillary molars and maxillary sinus floor using cone-beam computed tomography (CBCT) in the southern Turkish subpopulation., Design: For the study, 246 CBCT images were analyzed. The absence of antagonist teeth was excluded. Kwak's types III and V were detailed with three divisions. Division M; the penetration of the mesial root only, Division D; the penetration of the distal root only, and Division MD; the penetration of both buccal roots. The distance between the maxillary sinus and the root apices was measured. Student's t-test, one-way ANOVA, and chi-square were used for statistical analysis., Results: The penetration of maxillary molars was 24.40%. The highest prevalence belonging to Type I. Division MD was 44.35% for Type III and 40.42% for Type V. Division M was higher than Division D. The distances between the sinus and root apices were 1.35-2.41 mm in Type I. The distance decreased with age (p < 0.05)., Conclusion: Both buccal root penetration into the sinus was higher than the single root penetration. The distance of the second molar root apices to the sinus was closer than the first molar. One-quarter of the first and second molars were inside the sinus. A greater likelihood of penetration of the root apices into the sinus with increased age., 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.)

Aim: To describe the management of the palato-mesiobuccal (PMB) canal in maxillary second molars with fused roots using conventional techniques., Summary: Root canal treatment success hinges upon effectively addressing the intricate and variable anatomy of molar teeth. Failure to do so can lead to persistent infections and treatment failure. Recent advancements in imaging technologies have provided unparalleled insights into dental anatomy, especially in molars. Among these discoveries is the PMB canal, a unique anatomical variant recently reported for the first time in Endodontic literature. This canal, found in maxillary second molars with fused roots and originating from the coronal third of the palatal canal while traversing towards the mesiobuccal root presents challenges in clinical management due to its location. This article is the first to showcase the management of the PMB canal using conventional techniques. In the first case, a 38-year-old male patient presented with asymptomatic irreversible pulpitis in the maxillary second right molar. Following thorough instrumentation and irrigation, the presence of the PMB canal was discovered during root canal preparation. The canal was managed using rotary instruments and obturated successfully, resulting in a symptom-free tooth at an 8-year follow-up. The second case illustrates a similar scenario in a 23-year-old female patient presenting with symptomatic irreversible pulpitis in tooth 17. The PMB canal was identified during treatment and managed using rotary nickel-titanium instruments, leading to a favourable outcome at a 9-year follow-up., Key Learning Points: In fused roots of maxillary second molars, a PMB canal might be expected. Exploration of the buccal wall of the palatal canal under magnification after shaping procedures can reveal the PMB canal orifice in fused roots. Small tapers are suggested for the enlargement of the PMB canal. Continuous bleeding spots in the palatal canal might indicate a possible PMB canal orifice in vital cases. The use of an apex locator is suggested for the differential diagnosis of the PMB canal orifice from a perforation site., (© 2024 British Endodontic Society. Published by John Wiley & Sons Ltd.)

The aim of this study was to evaluate the stress induced by clamps made of different materials on mandibular first molar teeth using finite element analysis. The tooth model to be used in the study was created using micro-CT scanner and the rubber dam clamp model was created in three dimensions (3D) using Solidworks and applied to a finite element tooth model of an intact mandibular first molar. The size of the clamp opening and the force to be applied were calculated according to the buccolingual distances of the tooth. The contact areas of the clamps on the tooth were determined and subjected to force. The stress distribution patterns and maximum von Mises stresses were calculated and compared against these forces. The most stress against these forces occurred in the enamel tissue on the distal side where the clamp was in contact with the tooth. The stress value in the stainless steel clamp (191.63 MPa) was approximately 85% higher than the clamp made of polyethylene ketone (103.85 MPa). The stress in the dentin and pulp tissue of the tooth was negligible. Clinicians should examine the enamel tissue below the equatorial line of the tooth in detail before clamp application. The forces exerted by stainless steel clamps can cause damage to the enamel tissue of the tooth or progression of an existing enamel crack.

Objectives: This ex vivo diagnostic study aimed to externally validate an open-access artificial intelligence (AI)-based model for the detection, classification, localisation and segmentation of enamel/molar incisor hypomineralisation (EH/MIH)., Methods: An independent sample of web images showing teeth with (n = 277) and without (n = 178) EH/MIH was evaluated by a workgroup of dentists whose consensus served as the reference standard. Then, an AI-based model was used for the detection of EH/MIH, followed by automated classification and segmentation of the findings (test method). The accuracy (ACC), sensitivity (SE), specificity (SP) and area under the curve (AUC) were determined. Furthermore, the correctness of EH/MIH lesion localisation and segmentation was evaluated., Results: An overall ACC of 94.3 % was achieved for image-based detection of EH/MIH. Cross-classification of the AI-based class prediction and the reference standard resulted in an agreement of 89.2 % for all diagnostic decisions (n = 594), with an ACC between 91.4 % and 97.8 %. The corresponding SE and SP values ranged from 81.7 % to 92.8 % and 91.9 % to 98.7 %, respectively. The AUC varied between 0.894 and 0.945. Image size had only a limited impact on diagnostic performance. The AI-based model correctly predicted EH/MIH localisation in 97.3 % of cases. For the detected lesions, segmentation was fully correct in 63.4 % of all cases and partially correct in 33.9 %., Conclusions: This study documented the promising diagnostic performance of an open-access AI tool in the detection and classification of EH/MIH in external images., Clinical Significance: Externally validated AI-based diagnostic methods could facilitate the detection of EH/MIH lesions in dental photographs., 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.)

Introduction: The aim of this study was to evaluate changes in geometry following root canal preparation using R-Motion instruments with different apical sizes and tapers., Methods: Fifty-four mesial canals of mandibular molars with single curvature of angles ranging between 20° and 30° were stratified into 3 groups according to their internal anatomy (R-Motion 25/.06, 30/.04, Reciproc Blue) (n = 18 per group). Micro-computed tomography was used to standardize the samples before instrumentation and, after instrumentation, to assess canal transportation, changes in canal volume and centering ability. Canals were irrigated with 17% EDTA and sodium hypochlorite, and the final rinse included subsonic agitation of these solutions. Measurements were analyzed automatically using the Dragonfly software (Come, Montreal, Canada) and were confirmed by a technician and an endodontist, based on a previously validated methodology. The results were analyzed using the Kruskal-Wallis's and Mann-Whitney's tests. The level of statistical significance was set at 5%., Results: Significant differences were found in the coronal third for canal transportation, with Reciproc Blue R25 having greater values compared with both R-Motion instruments (P < .05) and greater changes in volume when compared with R-Motion 30/.04 (P < .05)., Conclusions: R-Motion of apical size and taper 25/.06 and 30/.04 were associated with similar changes in geometry following root canal preparation in curved mesial canals of mandibular molars, whereas Reciproc Blue was associated with greater canal transportation in the coronal root third., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Taurodontism is a dental morphological anomaly characterized by enlarged pulp cavities repositioned towards the apical region of the tooth, coupled with shortened root structures. Molars are commonly affected by this alteration. Certain populations exhibit up to 48% prevalences for this dental alteration, underscoring its significance in dental age estimation (DAE). In the field of DAE, an individual's chronological age is inferred from specific dental features, frequently employed within the forensic context. The effect of taurodontism on the features of DAE is an unanswered issue. The influence of taurodontism on eruption, mineralization, radiographic visibility of root canals, and radiographic visibility of the periodontal ligament space in mandibular third molars- some of the established criteria for DAE as examples-is currently not systematically examined. Some common staging scales for the dental features of DAE cannot technically be applied to taurodontic teeth. Additionally, given the association of taurodontism with syndromes affecting tooth development, caution is warranted in age assessment procedures. Notably, taurodontic teeth may serve as indicators of syndromes influencing skeletal development, further emphasizing the relevance of taurodontism in forensic age assessment. Presumably taurodontic teeth were included in reference data to some extent due to their partially high prevalence in the past, whereby the influence of taurodontism has been statistically absorbed within the overall spread of the features. Future studies should compare the temporal course of these tooth characteristics in affected and unaffected teeth. Subsequent initiatives should focus on raising awareness among forensic dentists regarding taurodontism, necessitating in-depth exploration of the subject., 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 The Author(s). Published by Elsevier B.V. All rights reserved.)

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.)

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.)

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.)

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.)

Preeruptive intracoronal radiolucency (PEIR) is a rare dental anomaly often incidentally detected during routine radiographic examinations. This condition manifests as a radiolucent lesion beneath the enamel-dentin junction of unerupted teeth, particularly in mandibular molars, posing diagnostic and management challenges due to its asymptomatic nature. The treatment of PEIR depends on the extent of the lesion and the degree of pulp involvement. Case series: This case series reports on four patients with progressive PEIR. In Cases 1 and 2, lesions were incidentally discovered in panoramic radiographs during orthodontic planning (mandibular permanent second molars), and additional surgical exposure to access the lesion was required as teeth were only partially erupted. Interestingly, in Case 3, the PEIR was not visible in earlier radiographs though the crown of the tooth was already mineralized (mandibular permanent second molar). For Case 4, the tooth presented with symptoms of reversible pulpitis (mandibular permanent first molar). All lesions were treated with indirect pulp capping using biocompat-ible material. The patients were followed up for a period of up to 8 years to evaluate treatment success. Indirect pulp capping and restorations were found to be successful in all four cases in the last follow-up: 1 year (Case 2), 1.4 years (Case 4), 1.5 years (Case 1), and 8 years (Case 3). Conclusion: This case series demonstrates the effectiveness of early intervention via surgical exposure and indirect pulp capping and restoration for managing severe cases of PEIR. However, further research with larger samples and long follow-up is necessary.