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

This study explored a novel digital design and fabrication method for a double constrained split orthodontic miniscrew guide to improve the accuracy and safety of clinical miniscrew implantation and reduce related complications. A patient requiring miniscrew implantation was selected, and data were acquired using cone beam computed tomography (CBCT) and intraoral optical scanning. For the construction of a double constrained split guide including a screw-hole guide and an insertion rod guide, different types of software such as Mimics 24.0, Geomagic wrap 2021, and Materialise magics 21.0 were utilized for 3D reconstruction, model integration, and guide design. The guide was then fabricated via laser metal 3D printing. Model and intraoral try-in results demonstrated that the guide fitted well and was stable. Postoperative CBCT verified that the final miniscrew implantation site was consistent with the preoperative design, and no related complications occurred. This double constrained split orthodontic miniscrew guide provides a precise and safe digital solution for clinical miniscrew implantation.
Humans ; Bone Screws ; Cone-Beam Computed Tomography ; Printing, Three-Dimensional ; Orthodontic Anchorage Procedures/instrumentation* ; Imaging, Three-Dimensional ; Computer-Aided Design

OBJECTIVES: This study aimed to investigate the influence of the dimensional stability of 3D printed resin master model on the replication accuracy of implant replicas. METHODS: Ten digital impressions of patients undergoing continuous crowns or fixed bridge restoration supported by two implants were obtained, and resin models with implant replicas were 3D printed. Scanning rods were fixed on the replicas 3, 7, and 14 days after printing. The 3D, linear, and angular deviations of the scanning rods at different times were analyzed through Geomagic Wrap 2021 software. RESULTS: The position of the replicas shifted mesiolingually, in the same direction as the shrinkage of the model. From day 7 onward, the 3D, distance linear, and angular deviations of the replicas (scanning rod) significantly increased compared with those on the 3rd day (P<0.05). On the 14th day, the changes were even more pronounced, with the above deviations showing statistical significance (P<0.05) compared with those for the 3-day and 7-day groups. No statistical difference in height linear deviation was observed among the groups. CONCLUSIONS The insufficient dimensional stability of 3D printed resin models can lead to changes in the relative position and angle of the replicas, thereby affecting the accuracy of the replicas in recreating the implant's position. Complete manufacturing of prosthesis is recommended within 7 days after the model is printed.
Printing, Three-Dimensional ; Humans ; Dental Implants ; Models, Dental ; Dental Impression Technique ; Crowns

OBJECTIVE To evaluate the palatability and chewability of chewable tablets， and provide reference for the quality evaluation of various types of chewable tablets. METHODS Using self-made Glucosamine hydrochloride chewable tablets as the model drug， the quality test was conducted. The in vitro simulation system for chewable tablets was established by using a texture analyzer and rheometer， and an oral simulation experiment was conducted on chewable tablets. The texture analyzer was used to measure the force required for chewing and simulate the static disintegration process of chewable tablets； the rheometer was adopted to measure the viscoelasticity， thixotropy， and deformability of chewable tablets during the chewing process. RESULTS The disintegration time limit， principal component content， and dissolution of self-made Glucosamine hydrochloride chewable tablets all met the limit requirements. The in vitro simulation results of the texture analyzer showed that self-made chewable tablets were easy to chew in both axial and radial directions， and the force required for chewing was within the range of the chewing force of the teeth； chewable tablets could disintegrate at an appropriate time without being chewed and only taken in the oral cavity. The in vitro simulation results of the rheometer showed that the chewable tablets in the oral cavity exhibited a behavior of elasticity as the main factor and viscosity as the secondary factor through the continuous stirring of the tongue， and the viscosity of the chewable tablets gradually decreased with tongue stirring or tooth chewing； when chewing with teeth， the internal force of the chewing tablets decreased， causing plastic deformation and crushing. After being crushed， the shape couldn’t be restored， making it easy to chew and swallow. CONCLUSIONS The combination of texture analyzer and rheometer can be used to simulate the oral chewing process and evaluate the palatability and chewability of self-made Glucosamine hydrochloride chewable tablets. This model can provide reference for the evaluation of various chewable tablets.

Objective:To develop an efficient and robust method based on three dimensional facial landmarks for evaluating chin region asymmetry at the soft tissue level and to compare it with the tradi-tional mirror-overlap analysis method in order to test its availability.Methods:Standard symmetrical face was used for mental tubercle coordinate transformation so as to filter soft tissue three dimensional spatial angle and construct corresponding three dimensional spatial angle wireframe template.Ten patients aged 12-32 years with clinical chin region asymmetry diagnosis at the Department of Orthodontics of Peking University Hospital of Stomatology from November 2020 to November 2021 were randomly selected.Three dimensional soft tissue face scan data of the patients were collected by three dimensional face scanner and the landmark points were automatically determined by the Meshmonk non-rigid registration algorithm pro-gram,and in this way,the asymmetric three dimensional spatial angle wireframe template and corre-sponding spatial angle parameters were generated.Mirror-overlap analysis of face scan data was also per-formed in Geomagic Studio 2015 software and deviation color maps were generated.This study took mirror-overlap analysis as the gold standard method,the response rate of chin region asymmetry was eva-luated by the outcomes of the mirror-overlap analysis and three dimensional spatial angle wireframe tem-plate analysis.Results:Nine three dimensional spatial angle indicators were selected through coordinate transformation,and the response rate was calculated using mirror-overlap analysis as the gold standard method.Among these ten selected patients,the response rate of the total chin region asymmetry was 90％(9/10).Using the deviation value of mirror-overlap analysis as a reference,the response rate of chin region asymmetry in the X dimension was 86％,the response rate of chin region asymmetry in the Y dimension was 89％,and the response rate of chin region asymmetry in the Z dimension was 100％.Conclusion:The three dimensional soft tissue spatial angle wireframe template proposed in this study has some feasibility in evaluating chin region asymmetry at the soft tissue level,and its ability to recognize asymmetry separately in the three dimensional direction is better than the mirror-overlap analysis method,and the indicators recognition rate still needs to be further improved.

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.

Objective : To explore the characteristics of impaired attention network function in chronic insomnia pa- tients． Methods : Polysomnography ( PSG) ，sleep scale ，attention network test ( ANT) and neuropsychological cognitive scale were used to evaluate the sleep quality，attention network function and cognitive function of 73 pa- tients with chronic insomnia and 65 healthy subjects. Results : Compared with normal control group，the scores of pittsburgh sleep quality index(PSQI) and insomnia severity index (ISI) in the chronic insomnia group increased， total sleep time reduced，sleep latency prolonged，sleep efficiency decreased，wake after sleep onset and arousal index increased，the proportion of non-rapid eye movement sleep stage 1 increased，the proportion of non-rapid eye movement sleep 3 and the proportion of rapid eye movement sleep decreased，and differences were statistically sig- nificant (all P＜0．05) ．In the attention network test，the efficiency of executive control network decreased in the chronic insomnia group，and the difference was statistically significant (all P＜0. 05) ．In neuropsychological tests， patients in the chronic insomnia group had spent more time on the Stroop color word test-word and trail making test- B．Correlation analysis showed that executive control function was associated with decreased non-rapid eye move- ment sleep stage 3 andincreased PSQI scores in chronic insomnia group． Conclusion Chronic insomnia patients have a certain degree of cognitive impairment，mainly executive control network impairment，which is associated with slow-wave sleep reduction.

Objective:To explore the risk factors of postpartum sepsis and provide references for clinical prevention of postpartum sepsis.Methods:The clinical data of postpartum patients who were treated and delivered in the maternity ward of Shengjing Hospital Affiliated of China Medical University from January 2016 to December 2018 were analyzed retrospectively. Among them, 99 patients with postpartum sepsis were assigned to the case group and 212 patients without postpartum sepsis in the same period were selected with a simple random method and as the control group. The clinical data of the two groups were collected by consulting the hospital electronic medical record system. Single factor and multivariate Logistic regression were applied to analyze the risk factors of postpartum sepsis.Results:The infection sites of 99 postpartum sepsis patients were mainly genital tract and respiratory system, accounting for 28.28% (28/99) and 26.26% (26/99), respectively. In blood culture of 99 cases of postpartum sepsis patients, 58.59% (58/99) pathogens of Gram-positive bacteria were detected with the highest proportion, among which Streptococcus was mainly, accounting for 23.23%(23/99). The proportion of Gram-negative bacteria was 38.38%(38/99), and Escherichia coli was mainly, accounting for 31.31% (31/99). Multivariate Logistic analysis showed that gestational diabetes ( OR = 2.643, 95% CI 1.123 - 6.276), genital tract infection ( OR = 7.542, 95% CI 3.571-15.959), vaginal trial (switch to cesarean section) ( OR = 1.218, 95% CI 1.008-1.493), premature rupture of membranes ( OR = 1.152, 95% CI 1.019 - 1.449), postpartum hemorrhage ( OR = 1.562, 95% CI 1.263 -1.881) and cesarean delivery ( OR = 2.074, 95% CI 1.442 - 2.993) were the risk factors of postpartum sepsis. Conclusions:The main risk factors affecting postpartum sepsis includes gestational diabetes, genital tract infection, vaginal trial (switch to cesarean section), premature rupture of membranes, postpartum hemorrhage and cesarean delivery. It is necessary to take corresponding intervention measures to strengthen prevention of these risk factors, which is of great significance for prevention and treatment of postpartum sepsis.

Objective To evaluate the therapeutic effect of NeuroD protein on radiation-induced intestinal injuries.Methods The expression and purification of NeuroD-enhanced green fluorescent protein (EGFP) fusion protein was performed in prokaryotic expression system.The efficiency of the fusion protein transduction into cells was monitored under fluorescence microscope.C57BL/6J mice were randomly divided into four groups with 10 mice in each group:normal control group,PBS group,EGFP group,and NeuroD-EGFP group.Besides the normal control group,the other three groups of mice received 9 Gy γ-ray total body irradiation.Intestinal tissues were collected,frozen sections were prepared to monitor the distribution of NeuroD in mice intestinal tract under fluorescence microscope,and pathological sections were prepared for H&E staining to evaluate the therapeutic effect of NeuroD protein.Results The NeuroD-EGFP fusion protein was purified by Ni-NTA column and verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).Visible green fluorescence gathered within the cells after NeuroD-EGFP fusion protein was added in the culture medium,suggesting that NeuroD-EGFP could penetrate the cell membrane into the cells.Five hours after intraperitoneal injection of NeuroD-EGFP,visible green fluorescence gathered within the intestinal epithelial cells in villi.At 3.5 d after irradiation,NeuroD-EGFP treated mice showed significantly higher villus (F =49.49,P ＜ 0.01) and crypt depth (F =16.72,P ＜ 0.01) and more crypts per circumference (F =10.32,P ＜ 0.01) compared with PBS and EGFP groups.Conclusion NeuroD protein can accelerate the post-irradiation recovery of injured villi and crypt of intestinal tract and could be used to treat radiation-induced intestinal injuries.