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: To detect prfA and hly toxin genes of Listeria monocytogenes using polymerase chain reaction (PCR) and colloidal gold technology. METHODS: L. monocytogenes DNA was extracted by boiling method. With prfA and hly of L. monocytogenes as the target genes, the 5' ends of upstream and downstream primers of prfA gene were labeled with 6-FAM and biotin, and the 5' ends of upstream and downstream primers of hly gene were labeled with digoxin and biotin, respectively, to establish the toxin gene detection method. Using cloning transformation, sequencing analysis, cloning of positive control products, the detection kid was developed and its specificity, sensitivity, reproducibility and stability were tested, followed by verification with sample testing. RESULTS: The concentration of L. monocytogenes DNA extracted by boiling method was 148.81±0.97 ng/μL, and the A₂₆₀/A₂₈₀ ratio ranged from 1.8 to 2.0. The PCR products showed a 100% homology with the gene sequences in GenBank database after cloning, transformation and sequencing. The colloidal gold strip yielded positive results only for L. monocytogenes samples without cross-reactions with Staphylococcus aureus, Escherichia coli or Bacillus cereus, and its minimum detection limit was 10^-2 ng/μL, demonstrating a 10-fold greater sensitivity of the test than agarose gel electrophoresis. The test also showed good reproducibility of the results when performed by different operators with good stability of the test strips after storage for 6 to 12 months. The test results showed that this kit could accurately and quickly detect L.monocytogenes in the test samples. CONCLUSIONS The detection kit developed in this study can simultaneously detect prfA and hly toxin genes of L. monocytogenes with good specificity, sensitivity, reproducibility and stability for use in food safety inspection.
Listeria monocytogenes/isolation & purification* ; Gold Colloid ; Bacterial Toxins/genetics* ; Polymerase Chain Reaction/methods* ; Hemolysin Proteins/genetics* ; Bacterial Proteins/genetics* ; DNA, Bacterial/genetics* ; Food Microbiology ; Heat-Shock Proteins

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 operational accuracy and operative time of oral surgery robot-assisted endodontic microsurgery on a head-simulator for clinical reference.Methods:Three pairs of surgical simulation models were set up on head-simulator. Each model included 10 positions anteriorly and posteriorly, 20 teeth for each technique, for a total of 60 teeth. An attending physician with more than 3 years clinical experience in endodontic microsurgery completed fixed-point osteotomy and apicoectomy in three groups of endodontic microsurgery under freehand (FH), static navigation (SN), and surgery robot (SR). The duration of each operation was recorded. Cone-beam CT was taken before the operation and the surgical path was planned in the software; after surgery, a plug gauge (precision gauge for measuring hole dimensions) was inserted into the surgical path for intraoral scanning. Surgical accuracy (starting point, end point, and angular deviation) was assessed in all 3 groups, and surgery time was compared.Results:The deviation at the starting point and the end point, and angular deviation was (0.37±0.11), (0.37±0.10) mm, and 0.71°±0.17°in the SR group. The deviations in the SR group were significantly lower than those in the SN group [(0.59±0.14), (0.65±0.18) mm, and 2.64°±0.75°] ( P<0.05), and both groups were significantly lower than the FH group [(1.37±0.31), (1.10±0.21) mm, and 9.84°±3.15°] ( P<0.05). The operative time in the SN group [(1.20±0.03) min] was significantly less than that in the SR group [(2.18±0.03) min] ( P<0.05), and both groups were significantly less than that in the FH group [(8.70±3.15) min] ( P<0.05). Starting point deviation, end point deviation, and angular deviation [(1.09±0.10), (0.90±0.07) mm, 7.22°±1.13°] in anterior teeth using the FH was significantly lower than the starting deviation, endpoint deviation, and angular deviation [(1.65±0.14), (1.30±0.06) mm, 12.46°±2.10°] in the posterior teeth using FH ( P<0.05), and the operative time in the anterior teeth using the FH [(5.75±0.57) min] was significantly less than that in the posterior teeth using [(11.65±1.14) min] ( P<0.05). The difference in accuracy and operative time between using SN and SR on anterior and posterior teeth was not statistically significant ( P>0.05). Conclusions:Oral surgery robot-assisted endodontic microsurgery helps improving the accuracy of clinicians′ operations and shorten the operation time.

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 theory of “manifestation-body and spirit-qi”， it is considered that the pathogenesis of tic disorders （TD） involves three manifestations of “wind， phlegm and fire”， with wind as the leading factor and phlegm and fire as the accompanying factors. It is advocated to identify the abnormality of body and spirit， summarize the evolution of manifestation， and prescribe flexibly based on qi movement of zang-fu organs. Among them， the common symptoms related to tics are mostly belong to wind symptoms， which originated from lung qi failing to purify and liver qi over-ascent. The method of soothing liver wood and purifying lung gold is adopted， and modified Xiaochaihu Decoction （小柴胡汤） and Cangerzi Powder （苍耳子散） are recommended； Patients with prolonged illness and strange symptoms are often mixed with phlegm， which stemmed from the fact that spleen failing to rise clear and stomach failing to downward turbid. The method of raising spleen-earth and lowering stomach-earth is adopted， and modified Yigong Powder （异功散） and Erchen Decoction （二陈汤） are recommended； Patients with severe symptoms are often mixed with fire symptoms， which originated from discordance of water and fire and hyperactivity of heart fire. The method of interacting heart and kidney and coordinating water and fire is adopted， and modified Xiegan Pill （泻肝丸） and Liuwei Dihuang Pill （六味地黄丸） are recommended， in order to regulate qi movement， harmonize body and spirit， and improve the symptoms.

【Objective】 To investigate the differences in efficacy and long-term prognosis between locally progressive low and intermediate rectal cancer patients receiving fluorouracil-based neoadjuvant chemotherapy alone (mFOLFOX6/CapeOX) and neoadjuvant radiotherapy, and to compare the therapeutic efficacy in the two groups. 【Methods】 We retrospectively analyzed the clinicopathological data of 118 patients with locally progressive low and intermediate rectal cancer who received neoadjuvant therapy from January 2019 to December 2021 at The First Affiliated Hospital of Xi’an Jiaotong University, including gender, age, body mass index (BMI), and other clinicopathological parameters. The t-test, Mann Whitney test, chi-square test or Fisher’s exact test were used to compare the differences between the two groups of patients who received neoadjuvant chemotherapy alone or neoadjuvant radiochemotherapy in terms of short-term efficacy, lymph node manifestations and long-term prognosis, respectively. Survival rates were calculated and survival curves were plotted using the Kaplan-Meier method. 【Results】 In terms of efficacy, patients in the neoadjuvant radiotherapy group achieved better tumor regression (Z=-2.05, P=0.04) and solid tumor efficacy (Z=-2.42, P=0.015), but the difference between the two groups in terms of downstaging effect of clinical stage was not statistically significant. The number of lymph nodes detected was significantly lower in the neoadjuvant radiotherapy group (neoadjuvant chemotherapy vs. neoadjuvant radiochemotherapy, 13.19±3.83 vs. 9.55±4.00, t=5.02, P<0.001), but the two groups did not differ significantly in the number of lymph node positives and lymph node positive ratio. In terms of long-term prognosis, there was no statistically significant difference in the overall survival rate or disease-free survival rate of the two groups. 【Conclusion】 Compared with neoadjuvant chemotherapy alone, neoadjuvant radiotherapy showed better short-term efficacy in patients with locally progressive low and intermediate rectal cancer, but there was no statistically significant difference between the two treatment regimens in terms of long-term prognosis.

BACKGROUND:The threaded conical implant has a good ability to control micro movements and is conducive to immediate loading.However,the effects of double-threaded conical cylindrical implants and conical cylindrical implants on stress distribution and initial stability of implant-bone interface after immediate loading have not been reported. OBJECTIVE:To investigate the impact of double-threaded conical cylindrical implants and conical cylindrical implants on the biological distribution of the implant and the surrounding bone interface during immediate loading in the mandibular molar region. METHODS:(1)Three-dimensional finite element analysis:Conical beam CT scans of the mandible and first molar of a volunteer were used to develop a basal model of the mandible.The double-threaded conical cylindrical implants and conical cylindrical implants were assembled with the mandibular models,and an immediate-load(or delayed implantation)implant model(a total of four models)for the first mandibular molar was established.Loads in four directions(100 N):axial,lingual and buccal 45°,mesial and distal,and buccal and lingual,were applied to the central fossa of each model's crown.Three-dimensional finite element method was used to analyze the implant displacement and the stress distribution at the implant-bone interface.(2)In vitro experiment:With the assistance of the oral implant robot,the double-threaded conical cylindrical implants and conical cylindrical implants were implanted on the same artificial bone pieces,separately,and the immediate load model of immediate implant implantation(or delayed implantation)was established in vitro(a total of four groups of models).Osstell resonance frequency analyzer and SmartPeg sensor were used to measure the implant stability coefficient in four vertical directions:front,rear,left,and right measurements,evaluate the initial stability,and verify the finite element analysis results. RESULTS AND CONCLUSION:(1)The displacement difference between double-threaded conical cylindrical implants and conical cylindrical implants was small when the immediate loading of delayed implantation was applied,but the maximum stress value of conical cylindrical implant-bone interface was greater than that of double-threaded conical cylindrical implant-bone interface.When the immediate loading of immediate implantation was applied,the maximum stress value and the maximum displacement of bone around the implant appeared when the load was applied in mesiodistal direction.The stress value of the conical cylindrical implant reached 298.84 MPa and the maximum displacement was 0.31 mm,both of which were larger than that of the double-threaded conical cylindrical implant.(2)The results of in vitro experiments showed that the stability coefficient of the double-threaded conical cylindrical implant was greater than that of the conical cylindrical implant.(3)Compared with the conical cylindrical implant,the double-threaded conical cylindrical implant has higher initial stability under immediate loading,suggesting that the use of double-threaded conical cylindrical implant should be given priority in clinical immediate loading.