Personalized composite scaffolds for accelerated cell- and growth factor-free craniofacial bone regeneration.

Approaches to regenerating bone often rely on integrating biomaterials and biological signals in the form of cells or cytokines. However, from a translational point of view, these approaches are challenging due to the sourcing and quality of the biologic, unpredictable immune responses, complex regulatory paths, and high costs. We describe a simple manufacturing process and a material-centric 3D-printed composite scaffold system (CSS) that offers distinct advantages for clinical translation. The CSS comprises a 3D-printed porous polydiolcitrate-hydroxyapatite composite elastomer infused with a polydiolcitrate-graphene oxide hydrogel composite. Using a micro-continuous liquid interface production 3D printer, we fabricate a precise porous ceramic scaffold with 60 wt% hydroxyapatite resembling natural bone. The resulting scaffold integrates with a thermoresponsive hydrogel composite in situ to fit the defect, which is expected to enhance surface contact with surrounding tissue and facilitate biointegration. The antioxidative properties of citrate polymers prevent long-term inflammatory responses. The CSS stimulates osteogenesis in vitro and in vivo. Within 4 weeks in a calvarial critical-sized bone defect model, the CSS accelerated ECM deposition (8-fold) and mineralized osteoid (69-fold) compared to the untreated. Through spatial transcriptomics, we demonstrated the comprehensive biological processes of CSS for prompt osseointegration. Our material-centric approach delivers impressive osteogenic properties and streamlined manufacturing advantages, potentially expediting clinical application for bone reconstruction surgeries.

MOF-Derived Zn/N-Doped Porous Carbon Film on a Carbon Nanotube for High-Performance Supercapacitors.

Designing high-performance binder-free electrochemical electrodes is crucially important toward supercapacitors. In this paper, a Zn/N-doped porous carbon film coating on flexible carbon nanotubes (ZIF-8@CT-800) derived from the epitaxial Zn-MOF film growth on cotton textile was successfully fabricated via a combination of the liquid-phase epitaxial (LPE) method and calcination treatments. The ZIF-8@CT-800 serves directly as a self-supported electrode for supercapacitors and exhibits a high areal capacitance of 930 mF·cm-2 at a current density of 1 mA·cm-2 and a good recyclability of 86% after 2000 cycles. The excellent supercapacitor property is ascribed to the unique structural design of ZIF-8@CT-800, which provides appropriate channels for enhanced electronic and ionic transport as well as increased surface area for accessing more electrolyte ions. This work will provide significant guidance for designing MOF-derived porous carbon to construct flexible binder-free electrode materials with high electrochemical performance.

Accuracy of implant height and width measurement with triaxial rotation method based on cone-beam CT.

Objective: To investigate the accuracy of implant height and width measurement in the mandibular and maxillary first molar region based on cone-beam CT (CBCT) data, and to establish an accurate method for bone measurement in the implant region. Materials and methods: CBCT images of 122 patients with implant in mandibular or maxillary first molar region were retrospectively collected. Two methods were used to measure sagittal height (SH), coronal height (CH), sagittal width (SW), and coronal width (CW) of implants. Method 1 (general method): the images were analyzed using the built-in software NNT 9.0 software. SHl, CHl, SWl, and CWl were measured on the reconstructed sagittal and coronal based on the radiologist's own experience. Method 2 (triaxial rotation method): the raw data were demonstrated in Expert mode of NNT 9.0 software, in which the coronal axis and sagittal axis were rotated paralleling to the long axis of the implant for reconstruction, and then SH2, CH2, SW2, and CW2 were measured on the reconstructed sagittal and coronal images. The results of two methods were compared with the actual implant size (H0, W0). Paired T-test was performed for statistical analysis. Dahlberg formula was used to check the measurement error. Results: For method 1, there was no significant differences between SHl and H0 (P > 0.05), but significant differences between CHl and H0, SWl and W0, and CWl and W0 (P < 0.05). For method 2, there were no significant differences between all measurements and actual size (P > 0.05). The random error range measured using Dahlberg formula was 0.157-1.171 mm for general method and 0.017-0.05 mm for triaxial rotation method. Conclusion: The triaxial rotation method is accurate for implant height and width measurements on CBCT images and could be used in pre-operatively bone height and width measurement of potential implant sites.

The exploration of a compound cone-beam CT contrast agent for diagnosis of human extracted cracked tooth.

Objectives: This study aims to investigate the use of sodium iodide (NaI), dimethyl sulfoxide (DMSO), ethyl alcohol, and ethyl acetate as cone-beam CT (CBCT) contrast agents for diagnosing cracked teeth. The optimal delay time for detecting the number of crack lines beyond the dentino-enamel junction (Nd), the number of cracks extending from the occlusal surface to the pulp cavity (Np), and the depth of the crack lines was explored. Methods: 14 human extracted cracked teeth were collected, 12 were used for enhanced scanning, and 2 were used for exploring the characteristic of crack lines. The teeth were scanned in 3 CBCT enhanced scanning (ES) modes: ES1 using meglumine diatrizoate (MD); ES2 using NaI and DMSO, ES3 using NaI, DMSO, ethyl alcohol and ethyl acetate. Three delay times (15mins, 30mins, and 60mins) were set for scanning. Nd, Np, and depth of crack lines were evaluated. Results: There were totally 24 crack lines on 12 cracked teeth. Nd was 10 in ES1 at 60mins, 24 in ES2 at 60mins and 24 in ES3 at 15mins. Np was 1 in ES1 at 60mins, 10 in ES2 at 60mins and 21 in ES3 at 60mins, and there were significantly different among them (p < 0.01). The average depth presented on ES3 was significantly deeper than ES1 and ES2 (p < 0.01). Conclusion: NaI, DMSO, ethyl alcohol and ethyl acetate show potential as contrast agents for enhanced CBCT scanning in diagnosis of cracked teeth and their depth in vivo. A delay time of 15 min is necessary to confirm the existence of crack lines, while a longer delay time is required to ascertain if these crack lines extend to the pulp cavity.

Design, Preparation, and Implementation of Axially Chiral Benzotetramisoles as Lewis Base Catalysts for Asymmetric Cycloadditions.

Developing novel catalysts with potent activity is of great importance in organocatalysis. In this study, we designed and prepared a new class of benzotetramisole Lewis base catalysts (AxBTM) that have both central and axial chirality. This unique feature of these catalysts results in a three-dimensional microenvironment with multi-layers of chirality. The performance of the developed catalysts was tested in a series of cycloaddition reactions. These included the AxBTM-catalyzed (2+2) cycloaddition between α-fluoro-α-aryl anhydride with imines or oxindoles, and the sequential gold/AxBTM-catalyzed (4+2) cycloaddition of enynamides with pentafluorophenyl esters. The interplay between axial and central chirality had a collaborative effect in regulating the stereochemistry in these cycloadditions, leading to high levels of stereoselectivity that would otherwise be challenging to achieve using conventional BTM catalysts. However, the (2+2) and (4+2) cycloadditions have different predilections for axial and central chirality combinations.

Exploring the potential of ChatGPT as an adjunct for generating diagnosis based on chief complaint and cone beam CT radiologic findings.

AIM: This study aimed to assess the performance of OpenAI's ChatGPT in generating diagnosis based on chief complaint and cone beam computed tomography (CBCT) radiologic findings. MATERIALS AND METHODS: 102 CBCT reports (48 with dental diseases (DD) and 54 with neoplastic/cystic diseases (N/CD)) were collected. ChatGPT was provided with chief complaint and CBCT radiologic findings. Diagnostic outputs from ChatGPT were scored based on five-point Likert scale. For diagnosis accuracy, the scoring was based on the accuracy of chief complaint related diagnosis and chief complaint unrelated diagnoses (1-5 points); for diagnosis completeness, the scoring was based on how many accurate diagnoses included in ChatGPT's output for one case (1-5 points); for text quality, the scoring was based on how many text errors included in ChatGPT's output for one case (1-5 points). For 54 N/CD cases, the consistence of the diagnosis generated by ChatGPT with pathological diagnosis was also calculated. The constitution of text errors in ChatGPT's outputs was evaluated. RESULTS: After subjective ratings by expert reviewers on a five-point Likert scale, the final score of diagnosis accuracy, diagnosis completeness and text quality of ChatGPT was 3.7, 4.5 and 4.6 for the 102 cases. For diagnostic accuracy, it performed significantly better on N/CD (3.8/5) compared to DD (3.6/5). For 54 N/CD cases, 21(38.9%) cases have first diagnosis completely consistent with pathological diagnosis. No text errors were observed in 88.7% of all the 390 text items. CONCLUSION: ChatGPT showed potential in generating radiographic diagnosis based on chief complaint and radiologic findings. However, the performance of ChatGPT varied with task complexity, necessitating professional oversight due to a certain error rate.

The role of blood metabolites in oral cancer: insights from a Mendelian randomization approach.

Aim: This research aimed to explore the causal impact of blood metabolites on oral cancer using a two-sample Mendelian randomization (MR) analysis. The study endeavored to identify potential biomarkers for oral cancer's clinical management. Materials and methods: Based on the large individual-level datasets from UK Biobank as well as GWAS summary datasets, we first constructed genetic risk scores (GRSs) of 486 human blood metabolites and evaluated the effect on oral cancer. Various statistical methods, including inverse variance weighted (IVW), MR-Egger, and weighted median, among others, were employed to analyze the potential causal relationship between blood metabolites and oral cancer. The sensitivity analyses were conducted using Cochran's Q tests, funnel plots, leave-one-out analyses, and MR-Egger intercept tests. Results: 29 metabolites met the stringent selection criteria. Out of these, 14 metabolites demonstrated a positive association with oral cancer risk, while 15 metabolites indicated a protective effect against oral cancer. The IVW-derived estimates were significant, and the results were consistent across different statistical methodologies. Both the Cochran Q test and the MR-Egger intercept test indicated no heterogeneity and pleiotropy. Conclusion: This MR study offers evidence of the role specific blood metabolites play in oral cancer, pinpointing several with potential risk or protective effects. These findings could be helpful for new diagnostic tools and treatments for oral cancer. While the results are promising, additional research is necessary to fully validate and refine these conclusions. This study serves as a foundational step towards more comprehensive understandings in the future.

[An analysis of the wall width before and after root canal therapy in mandibular second molars with C-shaped canals].

PURPOSE: To measure the wall width in mandibular second molars with C-shaped canals before and after root canal therapy using cone-beam CT(CBCT). METHODS: A total of 55 mandibular second molars from 38 patients which met the criteria for inclusion at Nanjing Stomatological Hospital, Affiliated Stomatological Hospital of Medical School of Nanjing University from January 2020 to July 2021 were analyzed．From this sample, ten teeth had been treated, while another 45 of them not. CT images of the teeth were reestablished by Mimics software 20.0. Then we made a section every 1mm perpendicular to the long axis of the teeth from apex to pulp floor. The first slice from apex to pulp chamber was named the slice 1. Along the slice 1 to crown 1 mm was called slice 1, and so forth. The wall thickness at different locations of all the slices was measured. The data was entered into SPSS 20.0 software package for analysis. RESULTS: Regardless of whether the teeth were treated or not, both the mesial and distal canal walls' average width were thicker than 1mm in all slices. At the same time, the mesial and distal canal walls' width were thicker than the width of buccal and lingual canal walls in all the slices from C-shaped root canal, except slices which were near pulp chamber(P＜0.05). As for the C-shaped root canals without root canal therapy, the width of lingual wall in the slice 1 to 4, as well as apex third root, was thinner than 1 mm. The width of buccal canal wall was thicker than the width of lingual canal wall in all slices except slice 11 and 12. As for the C-shaped root canals with root canal therapy, the width of buccal canal wall in slice 1 to 5, equivalent of apex half root, and the width of lingual wall in the slice 1 to 7, amount to apex two-thirds of root, was thinner than 1 mm. The width of buccal canal wall was thicker than the width of lingual wall in all slices except slice 1 and 9. There was no significant difference between the distal canal walls' width of C-shaped canals with and without root canal therapy(P＞0.05) . There was significant difference between the buccal canal walls' width of C-shaped canals with and without root canal therapy, as same as the mesial canal walls' width and the width of lingual canal wall (P＜0.05). CONCLUSIONS: The lingual canal walls' width in apex third root of C-shaped root canal were thin before canal preparation. The buccal walls' width in apex half root and the lingual canal walls' in apex two-thirds of root of C-shaped root canal were thin after canal preparation.

Epidemiological and CBCT characterizations of odontomas: A retrospective study of 87,590 subjects.

OBJECTIVES: This study aimed to assess the epidemiological and three-dimensional (3D) radiological characterizations of odontomas, as well as the spatial relationship between odontomas and gubernaculum tracts (GT). MATERIALS AND METHODS: We retrieved the cone-beam computed tomography (CBCT) data of 87,590 patients. Dentition, location, type, diameter of the odontomas, width of the dental follicle (DF), the spatial relationship between the odontoma and GT, and the influence on adjacent teeth were evaluated. RESULTS: Significant differences were found in age, dentition, location, Max/Min diameter, width of DF, impaction, retention, and root bending of adjacent teeth among different spatial relationships between the odontoma and GT (all p < 0.05), as well as in age, type and size, absence, impaction, malposition, and retention of adjacent teeth among different locations of odontomas (all p < 0.05). Compared to the odontomas without impaction, those with impaction had larger diameter (p < 0.05 in all directions). This statistically significant association was consistent for odontomas with malposition, while no similar result was observed in the maximum diameter. CONCLUSION: Our findings provide the preliminary data for clinicians to comprehensively understand the incidence, radiographic characterizations and symptoms of odontoma in Chinese population.

Patterns of stress distribution of endodontically treated molar under different types of loading using finite element models-the exploring of mechanism of vertical root fracture.

INTRODUCTION: The purpose of this study was to explore the mechanism of vertical root fracture (VRF) using three-dimensional finite element models (FEMs). METHODS: An endodontically treated mandibular first molar with a subtle VRF was collected and scanned with cone beam CT (CBCT). Three finite element analysis models were created: Model 1 had the actual endodontically treated root canal size; Model 2 had the same root canal size as the contralateral homonymous tooth; and Model 3 had the root canal size expanded by 1 mm based on Model 1. Different types of loading were performed on these 3 FEMs. The stress distribution on the cervical, middle, and apical planes was analyzed, and the maximum stress on the root canal wall was calculated and compared. RESULTS: In Model 1, the maximum stress around the root canal wall occurred in the cervical part of the mesial root under vertical masticatory force and in the middle part of the mesial root under buccal and lingual lateral masticatory forces. Additionally, there was a stress change zone in a bucco-lingual direction that corresponded with the actual fracture line. In Model 2, the maximum stress around the root canal was in the cervical part of the mesial root under both vertical and buccal lateral masticatory forces. For Model 3, the stress distribution was similar to that of Model 1, but greater under buccal lateral masticatory force and occlusal trauma force. In all three models, the maximum stress around the root canal wall was in the middle part of the distal root under occlusal trauma force. CONCLUSIONS: The uneven stress around the root canal in the middle part (presented as a stress change zone in a bucco-lingual direction) may be the cause of VRFs.

Clinical and imaging features of eight cases of Ewing sarcoma of the jaw.

OBJECTIVES: This study investigate the clinical and imaging features of Ewing sarcoma (ES) of the jaw. METHODS: Eight cases of pathologically diagnosed ES of the jaw from January 2010 to June 2022 were included in the study. Clinical and radiological features were retrospectively analyzed. RESULTS: Among the eight cases, the mean age at onset was 29.4 years, and the male to female ratio was 7∶1. The predilecting site was the posterior part of mandible, accounting for 75% of the cases. The lesions often exhibited early numbness of the lower lip and lymphadenopathy. The main radiographic manifestation of mandibular lesions was ill-defined radiolucency, mixed with fibrous or brush-like tumor matrix, and soft tissue mass. The maxillary ES lesions mainly presented as lytic bone destruction accompanied by adjacent soft tissue mass. Periosteal ossification was rarely seen. CONCLUSIONS: The clinical and imaging characteristics of ES in the jaw are helpful for its diagnosis.

Stereodivergent Construction of Csp3 -Csp3 Bonds Bearing Vicinal Stereocenters by Synergistic Palladium and Phase-Transfer Catalysis.

Synergistic catalysis has emerged as one of the most powerful tools for stereodivergent formation of Csp3 -Csp3 bonds bearing vicinal stereocenters. Despite the many successes that have been achieved in this field, stereodivergent Csp3 -Csp3 coupling reactions involving stabilized nucleophiles remain challenging because of the competing single-catalysis pathway. Herein, we report a synergistic palladium/phase-transfer catalyst system that enables diastereodivergent Csp3 -Csp3 coupling reactions of 1,3-dienes with stabilized nucleophile oxindoles. Both the syn and anti coupling products, bearing quaternary and tertiary vicinal stereocenters, could be selectively produced in good yields with high enantio- and diastereoselectivities. Non-covalent activation of the stabilized nucleophile via chiral ion pair in a biphasic system is a crucial success factor in achieving diastereodivergence.

Copper-Catalyzed Enantioselective C1,N-Dipolar (3+2) Cycloadditions of 2-Aminoallyl Cations with Indoles.

2-Aminoallyl cations are versatile 1,3-dipoles that could potentially be used for diverse (3+n) cycloaddition reactions. Despite some preliminary studies, the asymmetric catalytic transformation of these species is still underdeveloped. We herein report a binuclear copper-catalyzed generation of 2-aminoallyl cations from ethynyl methylene cyclic carbamates and their enantioselective (3+2) cycloaddition reaction with indoles to construct chiral pyrroloindolines. This transformation features a novel C1,N-dipolar reactivity for 2-aminoallyl cations.

Development of a predictive model for identifying previously undetected vertical root fractures.

This study aimed to develop a predictive model to screen for undetected vertical root fractures (VRFs) in root canal treated teeth. We included 95 root canal treated teeth with suspected VRFs; 77 for training and 18 for validation. Following clinical and cone-beam CT parameters were recorded: sex, tooth type, coronal restoration, time interval from completion of endodontic treatment to definitive diagnosis (TI), type of bone loss (BL), apical extent of root filling (AR) and the ratio of root filling diameter to the actual diameter in the coronal (1/3TA) and middle (2/3TA) root thirds. A predictive model p = 1/(1 - e-x ) was generated, where x = -7.433 + 1.977BL + 1.479 (2/3TA) + 1.102 AR; the sensitivity and specificity were 0.852 and 0.875 for training and 0.917 and 0.833 for validation. VRF teeth were more likely to have vertical bone loss and overfilled root canals. This model had a high diagnostic efficacy for VRFs.

Classification of furcation involvement of endodontically treated mandibular first permanent molars based on cone beam CT / 口腔疾病防治

Objective @#To classify the furcation involvement (FI) of endodontically treated mandibular first permanent molars based on cone beam computed tomography (CBCT), provide reference for individualized treatment of FI. @*Methods@#CBCT images of the FI of 164 endodontically treated mandibular first permanent molars from 163 patients in Nanjing Stomatological Hospital, Medical School of Nanjing University were collected retrospectively. On the CBCT images, the shape and extent of periapical and periodontitis bone resorption, the thickness of residual dentin in the pulp floor and root canal wall, and the periodontal bone resorption of the complete dentition were evaluated. The FI was classified into periodontal, periapical, perforated and mixed types.@* Results@#Among the 164 FIs of endodontically treated mandibular first permanent molars, the periapical type was the most common (41.5%), followed by the mixed type (26.2%), perforated type (18.3%), and periodontal type (14.0%). Among the 68 periapical-type FIs of endodontically treated mandibular first permanent molars, 48.5% were proper root canal filling, 44.1% were insufficient filling and 7.4% were overfilling. Among the 43 mixed-type FIs, the periodontal mixed periapical type was the most common (72.1%).@*Conclusion @#Detailed evaluation and classification of furcation involvement could be performed using CBCT images; therefore, the study has guiding significance for clinical treatment.

Effect of different acupuncture and moxibustion methods on functional dyspepsia caused by sequelae of COVID-19: A protocol for systematic review and meta-analysis.

BACKGROUND: Functional dyspepsia (FD) is a group of diseases that cannot be explained after routine clinical examination, and is characterized by postprandial fullness, early satiety, and upper abdominal pain or burning. According to the statistics, FD continues to become one of the high-risk sequelae of coronavirus disease 2019 (COVID-19), affecting patients' quality of life, increasing psychological burden and increasing economic costs. However, its optimal treatment is still an urgent problem. A large number of studies have shown that acupuncture and moxibustion is effective and safe in the treatment of FD caused by sequelae of COVID-19, which is of research value. Therefore, based on the current literatures, the effectiveness and safety of different acupuncture and moxibustion methods were systematically evaluated to provide possible alternative therapy on FD. METHODS: Studies search for eligible randomized controlled trials that use different acupuncture and moxibustion methods as the sole treatment on FD and their data extraction will be done by 2 researchers. In case of disagreement, a third researcher will be introduced for arbitration. Mean difference or relative risk with fixed or random effect model in terms of 95% confidence interval will be adopted for the data synthesis. To evaluate the risk of bias, the Cochrane risk of bias assessment tool will be utilized. The sensitivity or subgroup analysis will also be conducted when meeting high heterogeneity (I2 > 50%). RESULTS: This meta-analysis will provide an authentic synthesis of different acupuncture and moxibustion methods on FD caused by sequelae of COVID-19. CONCLUSION: This meta-analysis will evaluate the effect of acupuncture and moxibustion on FD caused by sequelae of COVID-19, providing evidence as to the treatment in these patients.

Diagnosis of in vivo vertical root fracture using deep learning on cone-beam CT images.

OBJECTIVES: Evaluating the diagnostic efficiency of deep learning models to diagnose vertical root fracture in vivo on cone-beam CT (CBCT) images. MATERIALS AND METHODS: The CBCT images of 276 teeth (138 VRF teeth and 138 non-VRF teeth) were enrolled and analyzed retrospectively. The diagnostic results of these teeth were confirmed by two chief radiologists. There were two experimental groups: auto-selection group and manual selection group. A total of 552 regions of interest of teeth were cropped in manual selection group and 1118 regions of interest of teeth were cropped in auto-selection group. Three deep learning networks (ResNet50, VGG19 and DenseNet169) were used for diagnosis (3:1 for training and testing). The diagnostic efficiencies (accuracy, sensitivity, specificity, and area under the curve (AUC)) of three networks were calculated in two experiment groups. Meanwhile, 552 teeth images in manual selection group were diagnosed by a radiologist. The diagnostic efficiencies of the three deep learning network models in two experiment groups and the radiologist were calculated. RESULTS: In manual selection group, ResNet50 presented highest accuracy and sensitivity for diagnosing VRF teeth. The accuracy, sensitivity, specificity and AUC was 97.8%, 97.0%, 98.5%, and 0.99, the radiologist presented accuracy, sensitivity, and specificity as 95.3%, 96.4 and 94.2%. In auto-selection group, ResNet50 presented highest accuracy and sensitivity for diagnosing VRF teeth, the accuracy, sensitivity, specificity and AUC was 91.4%, 92.1%, 90.7% and 0.96. CONCLUSION: In manual selection group, ResNet50 presented higher diagnostic efficiency in diagnosis of in vivo VRF teeth than VGG19, DensenNet169 and radiologist with 2 years of experience. In auto-selection group, Resnet50 also presented higher diagnostic efficiency in diagnosis of in vivo VRF teeth than VGG19 and DensenNet169. This makes it a promising auxiliary diagnostic technique to screen for VRF teeth.

Establishment of Narrow Root Fracture Models Using Modified Temperature Cycling Method and Diagnosis Using Different Cone-Beam CT Units.

Aim: Using a modified thermal cycling method to establish narrow root fracture models and evaluate the diagnosis efficiency of them using four different cone-beam CT (CBCT) units. Methodology. Fifty-six intact teeth were selected, and the crowns of the teeth were embedded using general purpose acrylic resin. 50 root fracture models were established by soaking these teeth in liquid nitrogen and hot water cyclically; 6 teeth were used as the negative control. All the 56 teeth were scanned with the smallest voxel size of four different CBCT units (NewTom VGi, Planmeca Promax 3D Max, Kavo 3D eXam, and Soredex Scanora3D). 10 teeth were randomly selected, and the roots were sliced using slow-speed saw to obtain horizontal root sections. Scanning electron microscope (SEM) was used to measure the width of the fracture lines (FLs). The CBCT images were evaluated for the presence or absence of fracture lines. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the diagnosis of FLs using the four CBCT units. Results: Fifty narrow root fracture models were successfully established, and 25 root sections with 45 FLs were acquired. The width of FLs was from 3.43 µm to 143 µm; 32.2% of the points had width under 25 µm, while only 9.6% of them had width over 75 µm. The accuracy was 0.41, 0.54, 0.41, and 0.30 for NewTom VGi, Planmeca Promax 3D Max, Kavo 3D eXam, and Soredex Scanora3D, respectively. Conclusions: The modified temperature cycling method is a simple and effective method to establish narrow root fracture models, and the diagnosis efficiency for these narrow fracture lines was quite poor using all the four different CBCT units.

Using deep learning to distinguish malignant from benign parotid tumors on plain computed tomography images.

Objectives: Evaluating the diagnostic efficiency of deep-learning models to distinguish malignant from benign parotid tumors on plain computed tomography (CT) images. Materials and methods: The CT images of 283 patients with parotid tumors were enrolled and analyzed retrospectively. Of them, 150 were benign and 133 were malignant according to pathology results. A total of 917 regions of interest of parotid tumors were cropped (456 benign and 461 malignant). Three deep-learning networks (ResNet50, VGG16_bn, and DenseNet169) were used for diagnosis (approximately 3:1 for training and testing). The diagnostic efficiencies (accuracy, sensitivity, specificity, and area under the curve [AUC]) of three networks were calculated and compared based on the 917 images. To simulate the process of human diagnosis, a voting model was developed at the end of the networks and the 283 tumors were classified as benign or malignant. Meanwhile, 917 tumor images were classified by two radiologists (A and B) and original CT images were classified by radiologist B. The diagnostic efficiencies of the three deep-learning network models (after voting) and the two radiologists were calculated. Results: For the 917 CT images, ResNet50 presented high accuracy and sensitivity for diagnosing malignant parotid tumors; the accuracy, sensitivity, specificity, and AUC were 90.8%, 91.3%, 90.4%, and 0.96, respectively. For the 283 tumors, the accuracy, sensitivity, and specificity of ResNet50 (after voting) were 92.3%, 93.5% and 91.2%, respectively. Conclusion: ResNet50 presented high sensitivity in distinguishing malignant from benign parotid tumors on plain CT images; this made it a promising auxiliary diagnostic method to screen malignant parotid tumors.

Oral and maxillofacial pain as the first sign of metastasis of an occult primary tumour: A fifteen-year retrospective study.

BACKGROUND: Metastatic adenocarcinoma of the jaw (MAJ) is a rare disease that accounts for 1%-3% of all oral and maxillofacial malignant tumours. Oral and maxillofacial pain may be the first symptom of metastatic spread of an occult primary tumour. Therefore, early identification of oral and maxillofacial pain by dental professionals is critical. AIM: To explore the clinical and computerized tomography (CT) features of MAJ with oral and maxillofacial pain as the first symptom. METHODS: The medical records of all patients who were treated in our hospital between January 2006 and February 2020, and diagnosed with MAJ with oral and maxillofacial pain as the first symptom, were reviewed retrospectively. Clinical data were collected on age, sex, medical history, clinical manifestations, site of metastasis, and site of the primary lesion. CT features were analysed in detail, and a radiological classification scheme comprising five types: Osteolytic, osteoblastic, mixed, cystic, and alveolar bone resorption was proposed. RESULTS: The primary sites of MAJ were the lungs (n = 6), liver (n = 4), kidneys (n = 2), prostate (n = 1), and gastric cardia (n = 1). Five tumours were classified as the osteolytic type, all with a permeative margin (100%, P < 0.05), and three were classified as the mixed type, mostly with a moth-eaten margin (80%, P < 0.05). The cystic (n = 3) and alveolar bone resorption (n = 1) types had geographic margins, and the osteoblastic type (n = 1) had sclerotic margins. Moreover, nine tumours showed periosteal reaction and five showed a localised soft tissue mass, while the occurrence of jaw expansion was relatively rare. CONCLUSION: MAJ has complex clinical and CT features. Oral and maxillofacial pain may be the first sign of a primary tumour affecting other sites.