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.

Objective:To evaluate the effectiveness of surgical methods for correcting pollybeak deformity in Chinese rhinoplasty.Methods:A retrospective chart review was conducted for patients who underwent pollybeak correction between January 2021 and December 2022 at the Department of Plastic and Aesthetic (Burn) Surgery, the Second Xiangya Hospital of Central South University. Individualized correction was tailored based on the etiology and severity of the nasal deformity of each patient, involving techniques such as resection of the anterior part of the nasal septum, reconstruction of nasal tip support, reconstruction of the middle part of the nasal vault, and excision of skin in the upper region of the nasal tip. A modified classification system for pollybeak deformity, the supratip fullness rating scale (SFRS), was developed to evaluate supratip fullness (0-3 points, with higher scores indicating more apparent deformity). The patients aesthetic outcomes were assessed by surgeons using the visual analogue scale (VAS) (0-10 points, with higher scores indicating more apparent deformity), and patient self-assessed using the rhinoplasty outcome evaluation (ROE) questionnaire (0-100 points, with higher scores indicating higher satisfaction). The measurement data of normal distribution was expressed as Mean±SD and analyzed by paired t-test; the measurement data of non-normal distribution was expressed as M( Q1, Q3) and analyzed by Wilcoxon signed rank test. Results:In a cohort study of 53 rhinoplasty patients (7 male, 46 female; age range 19-45 years, mean 29 years), comprising 15 primary and 38 secondary surgeries, nasal tip deformities were evaluated. Deformities were classified as mild (5 cases), moderate (25 cases), and severe (23 cases). Over a follow-up period of 6-17 months (mean 9.5 months), significant aesthetic improvements in the nasal tip region were observed. The SFRS scores decreased from 2(2, 3) preoperatively to 0(0, 0) postoperatively ( Z = -6.58, P < 0.001), and VAS scores decreased from 7.47±1.73 to 1.79±1.67 ( t = -25.61, P < 0.001). High patient satisfaction was indicated by a mean ROE score of 82.45±11.55. No significant complications, such as nasal tip ptosis, skin necrosis, or scar hyperplasia, were reported. Conclusion:Selecting an appropriate surgical method based on the severity and cause of pollybeak deformity can achieve satisfactory outcomes. Post-operative patients exhibit significant aesthetic improvement in the upper nasal tip area, resulting in high patient satisfaction.

Objective:To explore the clinical efficacy of modified superomedial pedicle technique using an inverted T-shaped incision for reduction mammaplasty and mastopexy.Methods:A retrospective analysis was conducted on clinical data of patients who underwent modified superomedial pedicle technique for breast reduction surgery with inverted T-shaped incision between March 2021 and March 2023 at the Department of Plastic and Aesthetic (Burn) Surgery, Second Xiangya Hospital of Central South University. Preoperatively, a handheld Doppler ultrasound blood flow detector was used to detect and mark the exit points of the 2nd to 4th perforating vessels of the internal thoracic artery, and a superomedial pedicle containing at least two perforators was designed based on the perforator locations, with a pedicle width generally about 6 cm. Intraoperatively, the pedicle was rotated superolaterally, moving the nipple-areola complex (NAC) upwards to construct a fuller upper pole of the breast and removing excess skin in the lower fold to form a inverted T-shaped incision. Postoperatively, the blood supply of the NAC, breast morphology, and incidence of complications were observed and followed up. Canfield Mirror 7.1.1 software was utilized to measure pre- and post-operative breast morphology data from lateral photographs at 6 months, including total breast area, maximum breast protrusion, upper pole protrusion, lower pole height, and nipple elevation height. The BREAST-Q questionnaire was used to survey patient satisfaction with breast appearance, psychosocial well-being, sexual well-being, and physical health before surgery and 6-12 months after surgery, with each dimension scoring 0-100 points, where higher scores indicate greater satisfaction and health. SPSS 28.0 software was used for data analysis, with normally distributed measurement data expressed as Mean±SD, and paired t-test was applied for comparisons of pre- and post-operative breast morphology data (the first 4 indicators) and BREAST-Q scores, with P<0.05 considered statistically significant. Results:A total of 56 female patients were included, with an age of (32.0±6.7) years and a body mass index of (29.1±5.7) kg/m 2. Preoperative Doppler ultrasound blood flow detection showed that none of the patients had missing or significantly variant perforators of the superomedial pedicle. The volume of breast tissue removed ranged from 890 to 1 800 ml, averaging 1 250 ml, with an average pedicle width of 5.4 cm (4.0-7.0 cm). The follow-up period was (13.3±2.5) months, during which all patients exhibited good blood supply to the NAC and favorable breast morphology, with universal high satisfaction with surgical outcomes. Postoperatively, one case developed incisional seroma, which resolved naturally within 3 months; two cases experienced minor incision dehiscence, which healed well after dressing changes; all other patients recovered well without any complications such as flap necrosis or hematoma. Comparison of breast morphology data showed significant reductions in postoperative left and right total breast area ( P<0.05 for both), and increases in maximum breast protrusion and lower pole height postoperatively ( P<0.05 for both), while the difference in upper pole protrusion was not statistically significant ( P>0.05 for both); postoperative left and right nipple elevation heights were (6.30±1.84) cm and (6.52±1.66) cm, respectively. Among the 44 patients who completed the BREAST-Q survey both before and after surgery, scores showed significant improvements in postoperative breast satisfaction [(50.30±10.30) points vs. (83.20±6.02) points] ( t=5.17, P=0.008) and psychosocial well-being [(56.20±17.20) points vs. (89.70±2.70) points] ( t=5.09, P=0.010), while sexual well-being and physical health scores did not differ significantly from preoperative scores ( P>0.05 for both). Conclusion:Preoperative identification of perforator locations using a handheld Doppler blood vessel detector, followed by the design of a modified superomedial pedicle technique for reduction mammaplasty with inverted T-shaped incision, can not only ensure NAC blood supply, avoiding ischemic necrosis due to vascular anomalies, but also maximally reduce pedicle width and increase pedicle rotation flexibility, achieving desirable breast shaping effects.

Objective:To compare and discuss the mid-to-long-term outcomes of mitral valve repair (MVP) versus biological mitral valve replacement (bMVR) in patients aged 60 years and above with rheumatic mitral valve disease.Methods:This is a retrospective cohort study. A total of 765 patients aged 60 years and older, diagnosed with rheumatic mitral valve disease and who underwent MVP or bMVR at Beijing Anzhen Hospital from January 2010 to January 2023, were retrospectively included. Among them, 186 were male and 579 were female, with an age of (66.1±4.5) years (range: 60 to 82 years). Patients were divided into two groups based on the surgical method: the mitral valve repair group (MVP group, n=256) and the bioprosthetic mitral valve replacement group (bMVR group, n=509). A 1∶1 propensity score matching was performed using a caliper value of 0.2 based on preoperative data. Paired sample t-tests, χ2 tests, or Fisher′s exact tests were used for intergroup comparisons. Kaplan-Meier method was employed to plot survival curves and valve-related reoperation rate curves for both groups before and after matching, and Log-rank tests were used to compare the mid-to long-term survival rates and valve-related reoperation rates between the two groups. Results:A total of 765 patients who completed follow-up were ultimately included, with a follow-up period ( M(IQR)) of 5.1(5.0) years (range: 1.0 to 12.9 years). After matching, each group consisted of 256 patients. The incidence of early postoperative atrial fibrillation (39.1% vs. 49.2%, χ2=4.95, P=0.026) and early mortality rates (2.0% vs. 6.2%, χ2=4.97, P=0.026) were lower in the MVP group. Unadjusted Kaplan-Meier analysis showed significantly higher 5-year and 10-year survival rates for the MVP group (92.54% vs. 83.02%, 86.22% vs. 70.19%, Log-rank: P=0.001). After adjustment with propensity scores, the Kaplan-Meier analysis still indicated higher 5-year and 10-year survival rates in the MVP group compared to the bMVR group (92.54% vs. 85.89%, 86.22% vs. 74.83%, Log-rank: P=0.024). There were no significant differences in the rates of valve-related reoperation between the two groups before and after matching (5-year and 10-year reoperation rates pre-matching: 1.75% vs. 0.57%, 5.39% vs. 7.54%, Log-rank: P=0.207; post-matching: 1.75% vs. 0, 5.39% vs. 9.27%, Log-rank: P=0.157). Conclusion:For patients aged 60 years and above with rheumatic mitral valve disease, mitral valve repair offers better mid-to-long-term survival compared to biological valve replacement.