OBJECTIVE: To develop an original-mirror alignment associated deep learning algorithm for intelligent registration of three-dimensional maxillofacial point cloud data, by utilizing a dynamic graph-based registration network model (maxillofacial dynamic graph registration network, MDGR-Net), and to provide a valuable reference for digital design and analysis in clinical dental applications. METHODS: Four hundred clinical patients without significant deformities were recruited from Peking University School of Stomatology from October 2018 to October 2022. Through data augmentation, a total of 2 000 three-dimensional maxillofacial datasets were generated for training and testing the MDGR-Net algorithm. These were divided into a training set (1 400 cases), a validation set (200 cases), and an internal test set (200 cases). The MDGR-Net model constructed feature vectors for key points in both original and mirror point clouds (X, Y), established correspondences between key points in the X and Y point clouds based on these feature vectors, and calculated rotation and translation matrices using singular value decomposition (SVD). Utilizing the MDGR-Net model, intelligent registration of the original and mirror point clouds were achieved, resulting in a combined point cloud. The principal component analysis (PCA) algorithm was applied to this combined point cloud to obtain the symmetry reference plane associated with the MDGR-Net methodology. Model evaluation for the translation and rotation matrices on the test set was performed using the coefficient of determination (R²). Angle error evaluations for the three-dimensional maxillofacial symmetry reference planes were constructed using the MDGR-Net-associated method and the "ground truth" iterative closest point (ICP)-associated method were conducted on 200 cases in the internal test set and 40 cases in an external test set. RESULTS: Based on testing with the three-dimensional maxillofacial data from the 200-case internal test set, the MDGR-Net model achieved an R² value of 0.91 for the rotation matrix and 0.98 for the translation matrix. The average angle error on the internal and external test sets were 0.84°±0.55° and 0.58°±0.43°, respectively. The construction of the three-dimensional maxillofacial symmetry reference plane for 40 clinical cases took only 3 seconds, with the model performing optimally in the patients with skeletal Class Ⅲ malocclusion, high angle cases, and Angle Class Ⅲ orthodontic patients. CONCLUSION This study proposed the MDGR-Net association method based on intelligent point cloud registration as a novel solution for constructing three-dimensional maxillofacial symmetry reference planes in clinical dental applications, which can significantly enhance diagnostic and therapeutic efficiency and outcomes, while reduce expert dependence.
Humans ; Deep Learning ; Algorithms ; Imaging, Three-Dimensional/methods* ; Male ; Female ; Maxilla/diagnostic imaging* ; Adult

OBJECTIVES: This study aimed to evaluate the repeatability and reliability of a self-developed domestic wireless surface electromyography (sEMG) system (Oralmetry) in assessing the activity of the temporalis and masseter muscles to provide theoretical support for its clinical application. METHODS: Twenty-two volunteers were recruited. Through multiple repeated measurements, the sEMG signals of bilateral anterior temporalis and masseter muscles during maximum voluntary clenching were collected using the self-developed sEMG device, Oralmetry, and two commercial sEMG devices (Zebris and Teethan), filtered, screened, and standardized. Seven sEMG indicators for assessing masticatory muscle function were calculated. The intraclass correlation coefficient (ICC) was used to evaluate the repeatability of the measurements from the three sEMG devices, and statistical analysis was conducted to compare the consistency of the seven sEMG indicators obtained from the devices. RESULTS: Among the 22 participants, the ICC values of the repeated measurements from the three sEMG devices ranged from 0.88 to 0.99. The measurements of three sEMG indicators (antero-posterior coeffificient, percentage overlapping coeffificient_MM, and percentage overlapping coeffificient_TA) obtained by Zebris were significantly different from those obtained by Oralmetry and Teethan (P<0.05). No significant differences in the measurements of the seven sEMG indicators were found between Oralmetry and Teethan. CONCLUSIONS Oralmetry and the two commercial sEMG devices demonstrated good repeatability in capturing sEMG indicators for evaluating masticatory muscle function. In particular, Oralmetry showed the highest ICC values. All three devices also exhibited good consistency in measuring sEMG indicators, and a high agreement was observed between the two wireless sEMG devices (Oralmetry and Teethan). These findings provide theoretical support for the clinical application of Oralmetry.
Humans ; Electromyography/methods* ; Masseter Muscle/physiology* ; Masticatory Muscles/physiology* ; Wireless Technology ; Reproducibility of Results ; Temporal Muscle/physiology* ; Male ; Adult ; Female ; Young Adult

OBJECTIVES: To evaluate the accuracy of a self-developed extraoral scanning system based on four-camera stereophotogrammetric technology in the acquisition of three-dimensional positional information on dental implants and conduct a comparative study involving an intraoral scanning system. METHODS: With the use of an in vitro edentulous jaw model with implants, extraoral (experimental group) and intraoral (control group) scanning systems were employed to obtain STL (Standard Tessellation Language) datasets containing three-dimensional morphological and positional information on scan bodies. In addition, a dental model scanner was used to obtain reference data. The three-dimensional morphological, linear, and angular deviations between groups and reference data were analyzed using Geomagic Wrap 2021 software to compare trueness and precision. RESULTS: The extraoral scanning system demonstrated superior trueness in three-dimensional morphological, linear, and angular deviations compared with the intraoral scanning system, with statistically significant differences (P<0.001). The extraoral scanning system also showed a higher precision in three-dimensional morphological deviation (P<0.001). As the number of implants increased, the extraoral scanning system exhibited increased three-dimensional morphological and linear deviations (P<0.001) but maintained a stable angular deviation. The intraoral scanning system displayed significant increases in three-dimensional morphological, linear, and angular deviations with the increase in the number of implants (P<0.05). CONCLUSIONS The stereophotogrammetry-based extraoral scanning system outperforms intraoral scanning system in terms of the accuracy for multi-unit implant positioning and provides a novel approach for attaining a fully digital workflow for implant rehabilitation in edentulous jaws.
Jaw, Edentulous ; Humans ; Dental Impression Technique ; Dental Implants ; Imaging, Three-Dimensional/methods* ; Photogrammetry/methods* ; Models, Dental

Objective:To explore the method of obtaining the key parameters of the average value articulator in healthy people based on mandibular movement trajectory data, with a view to providing a reference for the clinical application of the average value articulator.Methods:One hundred healthy volunteers (42 males and 58 females) with individual normal occlusion, aged 18-55 years old, who met the inclusion criteria were recruited from Beijing, and their mandibular movement trajectory data were collected. The left and right sagittal condylar inclination(SCI) and transversal condylar inclination(TCI) were obtained from the values of the articulator parameters which were generated in the mandibular movement analysis system.The SCI and TCI were grouped by gender and calculated separately for the two groups and the overall sample; the gender differences in the two parameters and the differences between the mean values of the two parameters and the average value articulator empirical values (35° for SCI and 15° for TCI) for the overall sample were compared.Results:The differences between SCI (35.8°±7.4°) and TCI [11.2° (11.3°)] in males and the corresponding parameters [35.6°±8.3° and 10.8° (9.5°), respectively] in females were not statistically significant ( t=0.10, P=0.922; Z=-0.60, P=0.552); the overall sample SCI (35.7°±7.9°) did not differ statistically from the average value articulator empirical value ( t=1.23, P=0.221), and the overall sample TCI [10.9° (10.3°)] was significantly smaller than the average value articulator empirical value ( W=5 825.00, P<0.001). Conclusions:The mandibular movement trajectory data of 100 adults with individual normal occlusion in this study shows that the gender factor does not affect the setting of the key parameters of the average value articulator, the SCI of the average value articulator empirical values is appropriate, and the TCI has the possibility of being on the large side. In the clinical use of the articulator to assist in the design of restorations, the parameter values should be rationally adjusted according to the actual situation of the patient′s dentition and mandibular movement.

Based on the domestic and foreign research on the application of self-disclosure in gynecological cancer patients, the relevant concepts, main modes of self-disclosure, measuring tools, research status and influencing factors of self-disclosure in gynecological cancer patients are reviewed. In order to provide a reference for the research on self-disclosure of gynecological cancer population, and promote the development of self-disclosure.

OBJECTIVE To explore how to shorten the time from approval to start-up of drug clinical trial project. METHODS Twenty-two phase Ⅱ-Ⅲ multi-center drug clinical trial projects start up in The First People's Hospital of Nanning from 2020 to 2021 were selected. The time-consuming of each link before the launch was analyzed, and the time- consuming of project approval, ethical review and contract review between the sponsor and research institution was compared, as well as the influence of using the contract template of each party on the time-consuming of contract review was compared. RESULTS Contract review took the longest time. There was no significant difference in the time-consuming between the sponsor and the research institutions in the three links of project approval, ethical review and contract review. Used the contract template of the research institutions, the time spent by the sponsor and the research institution in the review process, as well as the contract signing time of the project were shorter. CONCLUSION Using the clinical trial management system, conduct differentiated ethical review methods, advance drug delivery and commitment letter submission, use the contract template of research institutions or sign a framework contracts, establish a effective communication methods are all effective ways to reduce the time taken before start-up.

Cadmium sulfide nanoparticles are a new type of semiconductor nanomaterials used in many applications. Studies have shown that cadmium sulfide nanoparticles have toxic effects on the reproductive system， liver， and kidney of the body， and the toxicities are affected by various factors. This paper summarized the current research on the toxicity of cadmium sulfide nanoparticles at home and abroad， and reviewed the latest research progress on the mechanisms of its toxic effects and influencing factors.

Objective:To explore the existing issues in radiation protection during the treatment of 131I by means of measuring the ambient dose equivalent rate to patients with thyroid cancer and the dose equivalent to the surface of chest of patients during hospitalization. Methods:The ambient dose equivalent rate (peer) was measured by using gamma ray detector for selected 78 patients who received 131I treatment in a hospital 10 min, 1 d, 2 d, 3 d and 5 d after administration with 131I. The measurements were made at distances of 5 cm, 0.5 m and 1 m from the body surface in front, rear, left and right directions. The photoluminescence dosimeter on the chest of the patients was used to measure the effective dose during hospitalization period (6 d). Results:The ambient dose equivalent rate on the surface of chest of patients was up to 4.81 mSv/h 10 min after administration of medicine. The dose equivalent on the surface of chest of patients before discharge ranged 2.6-64.1 μSv/h. The cumulative dose on chest surface during hospitalization was 15.9-58.8 mGy. There was a significant difference in the dose rate at 5 cm from the body surface between 3.7 GBq group and 5.55 GBq group 10 min after medication ( t=-6.11, P<0.05). There was a significant difference in the dose rate at 5 cm from the body surface between male and female groups 10 min after medication ( t=4.52, P < 0.05). There was no significant difference in other groups ( P > 0.05). Conclusions:During the 131I treatment, patients had high level of radiation around them, so it is necessary to strengthen the protection and management of patients and reduce unnecessary exposure to the public.

Objective:To investigate the pathogenesis of pulmonary alveolar proteinosis in rats induced by nano-indium-tin oxide exposure, and to provide a basis for further determining the limit of occupational exposure to indium and developing related protection measures.Methods:In August 2018, a total of 40 specific pathogen-free Sprague-Dawley rats, with an age of 6-8 weeks and a body weight of (200±10) g, were randomly divided into control group, low-dose group (1.2 mg/kg) , middle-dose group (3 mg/kg) , and high-dose group (6 mg/kg) , with 10 rats in each group. After 1 week of routine feeding, the rats were given non-exposed intratracheal instillation twice every week, with an interval of 3 days, for 12 consecutive weeks. Body weight was measured every week during exposure to observe the change in body weight; The rats were anesthetized and sacrificed by chloral hydrate after the exposure ended, and lung tissue and serum were collected; Hematoxylin-eosin staining and periodic acid-Schiff (PAS) staining were performed for lung tissue to observe pathological results; Inductively coupled plasma mass spectrometry was used to measure the serum level of indium; ELISA was used to measure the levels of surfactant protein A (SP-A) , surfactant protein D (SP-D) , and the type II alveolar cell surface antigen Krebs von den Lungen-6 (KL-6) in lung tissue and the serum level of granulocyte-macrophage colony-stimulating factor (GM-CSF) .Results:The pathological results showed that the rats in the control group had basically complete alveolar structure, and after intratracheal instillation of nano indium-tin oxide, uniform, eosinophilic, and unstructured granular substances were observed in the alveolar space of the low-, middle-, and high-dose exposure groups, with macrophage proliferation and an increase in macrophages, especially in the high-dose group. Negative PAS staining was observed in the control group, while substances with positive PAS staining were observed in lung tissue in each exposure group. The three exposure groups had a significantly higher serum level of indium than the control group ( P<0.05) . Compared with the control group, the three exposure groups had significant increases in SP-A, SP-D, and KL-6 in lung tissue and a significant reduction in GM-CSF in serum ( P<0.05) . Conclusion:Pulmonary alveolar proteinosis in rats may be associated with the destruction of alveolar macrophages caused by nano-indium-tin oxide and the aggregation of pulmonary surfactants due to disorders in the metabolism and clearance of pulmonary surfactants by macrophages.

Objective:To investigate the pathogenesis of pulmonary alveolar proteinosis in rats induced by nano-indium-tin oxide exposure, and to provide a basis for further determining the limit of occupational exposure to indium and developing related protection measures.Methods:In August 2018, a total of 40 specific pathogen-free Sprague-Dawley rats, with an age of 6-8 weeks and a body weight of (200±10) g, were randomly divided into control group, low-dose group (1.2 mg/kg) , middle-dose group (3 mg/kg) , and high-dose group (6 mg/kg) , with 10 rats in each group. After 1 week of routine feeding, the rats were given non-exposed intratracheal instillation twice every week, with an interval of 3 days, for 12 consecutive weeks. Body weight was measured every week during exposure to observe the change in body weight; The rats were anesthetized and sacrificed by chloral hydrate after the exposure ended, and lung tissue and serum were collected; Hematoxylin-eosin staining and periodic acid-Schiff (PAS) staining were performed for lung tissue to observe pathological results; Inductively coupled plasma mass spectrometry was used to measure the serum level of indium; ELISA was used to measure the levels of surfactant protein A (SP-A) , surfactant protein D (SP-D) , and the type II alveolar cell surface antigen Krebs von den Lungen-6 (KL-6) in lung tissue and the serum level of granulocyte-macrophage colony-stimulating factor (GM-CSF) .Results:The pathological results showed that the rats in the control group had basically complete alveolar structure, and after intratracheal instillation of nano indium-tin oxide, uniform, eosinophilic, and unstructured granular substances were observed in the alveolar space of the low-, middle-, and high-dose exposure groups, with macrophage proliferation and an increase in macrophages, especially in the high-dose group. Negative PAS staining was observed in the control group, while substances with positive PAS staining were observed in lung tissue in each exposure group. The three exposure groups had a significantly higher serum level of indium than the control group ( P<0.05) . Compared with the control group, the three exposure groups had significant increases in SP-A, SP-D, and KL-6 in lung tissue and a significant reduction in GM-CSF in serum ( P<0.05) . Conclusion:Pulmonary alveolar proteinosis in rats may be associated with the destruction of alveolar macrophages caused by nano-indium-tin oxide and the aggregation of pulmonary surfactants due to disorders in the metabolism and clearance of pulmonary surfactants by macrophages.