BACKGROUND:Socket-shield technique can effectively maintain labial soft and hard tissues,but the incidence of postoperative complications such as exposure and displacement of root shield is relatively high.It is speculated that the root shield may be exposed and displaced due to excessive load after long-term function of dental implants. OBJECTIVE:Through three-dimensional finite element analysis,we aim to study the influence of varying root shield thicknesses on the stress distribution,equivalent stress peaks,and displacement in the root shield,periodontal ligaments,implant,and surrounding alveolar bone under normal occlusal loading.We also attempt to analyze the correlation between the thickness of the root shield and occurrence of mechanical events such as root shield exposure,displacement,and fracture. METHODS:Cone-beam CT data of a patient who met the indication standard of socket-shield technique for maxillary central incisor were retrieved from database.Reverse engineering techniques were used to build models of the maxillary bone and root shield,while forward engineering was used to create models for the implant components based on their parameters.Models depicting various root shield thicknesses(0.5,1.0,1.5,and 2.0 mm)were created using Solidworks 2022 software.ANSYS Workbench 2021 software was then used to simulate and analyze the effects of varying root shield thicknesses on stress distribution,equivalent stress peaks,and displacement of the root shields,periodontal ligaments,implants,and surrounding alveolar bone under normal occlusion. RESULTS AND CONCLUSION:(1)In all root shield models,the stress was concentrated on the palatal cervical side,both sides of the edges and the lower edge of the labial side.As the thickness of the root shield increased,the equivalent stress peak and displacement showed a decreasing trend.The 0.5 mm thickness model produced a stress concentration of 176.20 MPa,which exceeded the yield strength(150 MPa)of tooth tissue.(2)The periodontal ligament stress in each group was concentrated in the neck margin and upper region.With the increase of root shield thickness,the equivalent stress peak and displacement of periodontal ligament showed a decreasing trend.(3)Implant stress in all models was concentrated in the neck of the implant and the joint of the implant-repair abutment,and the labial side was more concentrated than the palatal side.With the increase of root shield thickness,the equivalent stress peak of the implant in the model showed an increasing trend.(4)In each group of models,stress of cortical bone concentrated around the neck of the implant and the periphery of the root shield,and the labial side was more concentrated than the palatal side.With the increase of the thickness of the root shield,the equivalent stress peak around the root shield decreased;the peak value of the equivalent stress of the bone around the neck of the implant showed an increasing trend.In the model,the stress of cancellous bone was mainly concentrated around the neck of the lip of the implant,the top of the thread,the root tip and the lower margin of the root shield,and the labial side was more concentrated than the palatal side.With the increase of the thickness of the root shield,the peak value of the equivalent stress of the bone around the root shield in the model showed a decreasing trend.The minimum principal stress of cortical bone in each group of models was concentrated around the neck of the implant,exhibiting a fan-shaped distribution.As the thickness of the root shield increased,the minimum principal stress of cortical bone showed an increasing trend.(5)These results indicate that different thicknesses of the root shield have different biomechanical effects.The root shield with a thickness of 0.5 mm is easy to fracture.For patients with sufficient bone width,the root shield with a thickness of 2.0 mm is an option to reduce the risk of complications such as root shield exposure,fracture,and displacement.Meanwhile,it should be taken into account to protect the periodontal ligament in the preparation process,and rounding treatments ought to be carried out on both sides and the lower edge of the root shield.

Objective:To establish and validate a gallstones classification method based on deep learning.Methods:A total of 618 gallstones samples were collected from East Hospital Affiliated to Tongji University, and 1 023 high-definition cross-sectional gallstones profile images were captured to construct a cross-sectional gallstones profile image dataset. Based on the traditional eight-category gallstones classification method, a lightweight network model, MobileNet V3, was trained using deep learning and transfer learning methods. The classification performance of MobileNet was evaluated using a confusion matrix with metrics such as accuracy rate, precision rate, F1 score, and recall rate. The MobileNet V3 was improved and further validated using accuracy and loss values.Results:The accuracy rate (94.17%), precision rate (94.03%), F1 score (92.96%) and recall rate (92.99%) of the improved MobileNet V3 model were better than other networks. The improved MobileNet V3 model achieved the highest accuracy rate (94.17%) in gallstones profile classification and was validated by the test set. The confusion matrix showed a weighted average of accuracy rate (92.0%), precision rate (92.6%), and F1 score (92.2%) for each category of gallstones.Conclusions:Based on deep learning, a high-accuracy gallstones classification method is proposed, which provides a new idea for the intelligent identification of gallstones.

The biological clock(also known as the circadian rhythm)is the fundamental reliance for all organisms on Earth to adapt and survive in the Earth's rotation environment.Circadian rhythm is the most basic regulatory mechanism of life activities,and plays a key role in maintaining normal physiological and biochemical homeostasis,disease occurrence and treatment.Recent studies have shown that the biologi-cal clock plays an important role in the development of oral tissues and in the occurrence and treatment of oral diseases.Since there is cur-rently no guiding literature on the research methods of biological clock in stomatology,researchers mainly conduct research based on pub-lished references,which has led to controversy about the research methods of biological clock in stomatology,and there are many confusions about how to rationally apply the research methods of circadia rhythms.In view of this,this expert consensus summarizes the characteristics of the biological clock and analyzes the shortcomings of the current biological clock research in stomatology,and organizes relevant experts to summarize and recommend 10 principles as a reference for the rational implementation of the biological clock in stomatology research.

The Internet has become an important carrier of medical information.Good electronic health literacy can enhance the public’s ability to obtain correct medical and health information with the help of electronic resources,which is helpful for the public to use health information to prevent diseases,avoid drug abuse,reduce the waste of medical resources and strengthen the self-management of chronic diseases.The improvement of electronic health literacy is of great value to the healthy development of citizens’ health literacy and healthy behavior.In view of the late start and slow development in the field of electronic health literacy in China,by combing the theoretical and practical research experience of electronic health literacy outside the region and combining with the COVID-19,this paper put forward new thinking on electronic health literacy in China,in order to provide useful reference for improving electronic health literacy of Chinese citizens,realizing self-care,self-management and disease prevention.

Objective To develop and validate a deep learning model for automatic identification of liver CT contrast-enhanced phases.Methods A total of 766 patients with liver CT contrast-enhanced images were retrospectively collected.A three-phase classification model and an arterial phase(AP)classification model were developed,so as to automatically identify liver CT contrast-enhanced phases as early arterial phase(EAP)or late arterial phase(LAP),portal venous phase(PVP),and equilibrium phase(EP).In addition,221 patients with liver CT contrast-enhanced images in 5 different hospitals were used for external validation.The annotation results of radiologists were used as a reference standard to evaluate the model performances.Results In the external validation datasets,the accuracy in identifying each enhanced phase reached to 90.50%-99.70%.Conclusion The automatic identification model of liver CT contrast-enhanced phases based on residual network may provide an efficient,objective,and unified image quality control tool.

BACKGROUND:Bone tissue remodeling is closely related to stress loading.Currently,there are few studies or guidelines on the relationship between bone and occlusal adjustment of implant prostheses and there is also a lack of scientific evidence. OBJECTIVE:To investigate the effects of different implant occlusal gaps on stress distribution,stress peak and displacement at the implant-bone interface under Ⅰ-Ⅳ bone conditions by a finite element method. METHODS:After scanning the equal-scale tooth model with an optical scanner,equal-scale models of the upper right first molar Straumann 4.8×8 mm BL RC implant and its related components was constructed using Solidworks 2022.Then,using Mimics,Geomagic,and Solidworks software,the maxillary and mandibular bone models of class Ⅰ-Ⅳ bones were established based on the bone classification proposed by ZARB and LEKHOLM in the literature,and the NORTON and TRISI bone density classification method.The models were assembled with the occlusal gaps of 0,20,40,60,80,and 100 μm for the restorations,and an additional set of homogeneous models without density ratio settings was constructed for comparison.After the above models were imported into Hypermesh for meshing,the material assignment,boundary constraints and parameter setting were performed for the finite element analysis.Finally,250 N was used as the loading force to simulate the maxillary and mandibular stress conditions.Stress distribution,peak stress and displacement of the implant-bone interface in each group of models were analyzed and compared. RESULTS AND CONCLUSION:Under the same loading conditions,the stresses in the implant restorations were evenly distributed with the occlusal contact points.When the occlusal gap reached 80 and 100 μm,stress interruptions occurred in the implant crowns under class Ⅰ bone and class Ⅱ,Ⅲ and Ⅳ bones,respectively.The displacement of the implant-bone interface was mainly concentrated in the cortical bone region around the implant and transmitted down the long axis of the implant to the cancellous bone region at the bottom.With the changes of class Ⅰ-Ⅳ jaw bones,the displacement and Von Mises stress in the cortical bone region increased in all groups,and were greater than those in the cancellous bone region.The Von Mises stress in the cancellous bone region was similar to that in the cortical bone region except that it showed a downward trend from class Ⅱ bone.However,when the occlusal gap increased,the stress and displacement peak values in the cortical bone and the cancellous bone showed a decreasing trend.The stress of the implant-bone interface was between 20 MPa and 60 MPa when the occlusal gap was 0-40 μm for class Ⅱ-Ⅳ bones and 60 μm for class Ⅳ bone,and the stress of the other groups was less than 20 MPa.The Von Mises stress was mainly concentrated in the neck of the implant,and the peak value of von Mises stress in class Ⅱ-Ⅳ bones with the occlusal gap of 20 μm was higher than that(144.10 MPa)in class Ⅰ bone with the occlusal gap of 0 μm.In the homogeneous model with different elastic moduli,the distribution of stress and displacement was more uniform than that in the heterogeneous model and the occlusal space should increase with the decrease of jaw bone density in clinical practice.To conclude,from the perspective of biomechanics,the alveolar bone should be taken into account in the occlusal adjustment of implant denture.An occlusal gap of 20-40 μm between a single dental implant and a natural tooth in the opposite jaw is a relatively suitable solution for occlusal adjustment under different bone conditions.However,due to the particularity of finite element analysis method,it needs to be further studied in combination with clinical practice.

Objective:To investigate the predictive value of preoperative D-dimer level for futile recanalization (FR) after mechanical thrombectomy (MT) in patients with acute ischemic stroke (AIS).Methods:It was a nested case-control study. A total of 116 patients with large vessel occlusion (LVO) stroke, who underwent successful recanalization (modified Thrombolysis in Cerebral Infarction, mTICI≥2b) after MT at the Stroke Unit of Beijing Hospital from August 2018 to January 2022,were consecutively enrolled, including 72 males (62.1%) with the age of (72.8±13.1) years. According to the 3-month modified Rankin Scale (mRS) score after MT, patients were divided into the meaningful recanalization group (mRS 0-2, n=41) and the futile recanalization group (mRS 3-6, n=75). The baseline clinical data of enrolled patients was collected. Logistic regression analysis was used to identify the independent risk factors for FR after MT in patients with AIS. Receiver operating characteristic (ROC) curve was used to evaluate the predictive value of D-dimer for FR. Results:Multivariate logistic regression analysis showed that high baseline systolic blood pressure (SBP) ( OR=1.038, 95% CI: 1.012-1.065, P=0.004), baseline National Institutes of Health Stroke Scale (NIHSS) score≥12 ( OR=10.157, 95% CI: 3.624-28.470, P<0.001) and high preoperative D-dimer level ( OR=4.536, 95% CI: 1.379-14.922, P=0.013) were independent predictors of FR after MT in AIS patients with LVO. ROC curve analysis indicated a good predictive value of preoperative D-dimer for the occurrence of FR ( AUC=0.733, 95% CI: 0.638-0.829, P<0.05), the optimal cut-off value of D-dimer was 2.65 μg/L(Lg), with the Youden index, sensitivity, specificity and accuracy of 0.435, 53.3%, 90.2% and 66.4%, respectively. Conclusion:High preoperative D-dimer level is an independent predictor of futile recanalization after MT in AIS patients with LVO, which shows good predictive ability for futile recanalization.

Objective:To analyze risk factors for unfavorable outcomes after recanalization of large vessel occlusion (LVO) in patients with acute ischemic stroke (AIS).Methods:Patients with AIS-LVO who underwent recanalization treatment (including intravenous thrombolysis and endovascular intervention) at the Stroke Unit of Beijing Hospital from August 2018 to January 2022 were consecutively enrolled. According to the modified Rankin Scale (mRS) at 90-day follow-up after recanalization treatment, participants were classified as unfavorable outcomes (mRS>2) and favorable outcomes (mRS≤2). Baseline clinical data of enrolled patients was collected, and step-wise multivariate logistic regression analysis was used to identify independent risk factors for unfavorable outcomes after recanalization in AIS-LVO patients.Results:A total of 212 AIS-LVO patients were enrolled, including 86 females (41.35%), with an average age of 72.9 years. There were 75 patients in the favorable outcome group and 137 patients in the unfavorable outcome group. Compared with the favorable outcome group, the unfavorable outcome group had a higher average age, a higher proportion of females and patients with atrial fibrillation, higher baseline NIHSS, higher systolic blood pressure, and higher blood creatinine and D-dimer levels (all P<0.05). After adjusting for age and atrial fibrillation as confounding factors, multivariate logistic regression analysis showed that female ( OR=2.859, 95% CI: 1.202-6.799, P=0.018), higher baseline NIHSS ( OR=14.417, 95% CI: 6.269-33.158, P<0.001), higher pre-treatment systolic blood pressure ( OR=1.034, 95% CI: 1.015-1.054, P=0.001), higher emergency blood creatinine level ( OR=1.378, 95% CI: 1.105-1.719, P=0.005), and higher D-dimer level ( OR=3.594, 95% CI: 1.290-10.014, P=0.014) were independent risk factors for unfavorable outcomes after recanalization treatment in patients with AIS-LVO. Conclusion:Female, higher NIHSS, higher systolic blood pressure, higher blood creatinine level and D-dimer level are independent risk factors for unfavorable functional outcomes at 90 days after recanalization treatment of large vessel occlusion in patients with acute ischemic stroke.

ObjectiveTo assess the curative effects of Fangji Huangqi detumescence prescription （FHDP） on synovitis and polarization of synovial macrophages of knee osteoarthritis （KOA） model in rats induced by Hulth method. MethodThirty-six rats were randomly divided into sham operation group， model group， high-dose， medium-dose， and low-dose （29.16， 14.58， and 7.29 g·kg^-1） FHDP groups， and loxoprofen sodium （16.2 mg·kg^-1） group. KOA model in rats was induced by modified Hulth method. Six weeks after the operation， rats were given high， medium， and low concentrations of FHDP， normal saline （NS）， and loxoprofen sodium according to the group to intervene， and sacrificed after 2-week administration. Synovium and cartilage histopathological changes were observed after hematoxylin-eosin （HE） staining. Flow cytometry （FCM） and immunofluorescence （IF） test were used to evaluate the polarization of M1/M2 macrophages. Immunohistochemistry （IMC） and enzyme-linked immunosorbent assay （ELISA） were used to detect the related protein expression levels of macrophage polarization， such as interleukin-1β （IL-1β）， tumor necrosis factor-α （TNF-α）， interleukin-10 （IL-10）， and matrix metalloproteinase-13 （MMP-13） in joint tissues and serum. ResultCompared with the sham operation group， Krenn and Mankin scores in the model group were significantly increased （P<0.01）. Compared with the model group， Krenn score was decreased in all administration groups （P<0.05， P<0.01）， but there was no significant difference in Mankin score in any administration groups. Compared with the sham operation group， M1/mø （CD38⁺） ratio in the model group was significantly increased （P<0.01）， and M2/mø （CD206⁺） ratio in the model group was decreased （P<0.05）. Compared with the model group， M1/mø ratio in the high， medium， and low-dose FHDP groups was decreased （P<0.05， P<0.01）， but M2/mø ratio was increased in all administration groups （the difference had no statistical significance）. Compared with the sham operation group， M1/M2 ratio in the model group was significantly increased （P<0.01）. Compared with the model group， M1/M2 ratio in all FHDP groups was significantly decreased （P<0.01）， and M1/M2 ratio in the high and medium-dose FHDP groups was lower than that in the loxoprofen sodium group （P<0.05）. Compared with the sham operation group， the levels of TNF-α， IL-1β， and MMP-13 in synovium and cartilage of the model group were significantly increased （P<0.01）， the level of IL-10 was significantly decreased （P<0.01）. Compared with the model group， the levels of TNF-α and IL-1β in synovium were decreased in all administration groups （P<0.05）， but the difference of the levels of MMP-13 and IL-10 in synovium had no statistical significance. The level of inflammatory mediators in cartilage was not affected in all administration groups. Compared with the sham operation group， the levels of TNF-α and IL-β in serum of the model group were significantly increased （P<0.01）， the level of IL-10 was decreased （P<0.05）. Compared with the model group， the level of TNF-α in the high-dose FHDP group was decreased （P<0.05）， and the level of IL-10 was increased in all administration groups （P<0.05， P<0.01）. The difference of the level of IL-β in all administration groups had no statistical significance. ConclusionFHDP attenuated the synovitis of KOA rats. FHDP exert the effect on the releasing of proinflammatory cytokines and MMP by inhibiting the polarization of M1 macrophages in synovium， and had no significant effect on the polarization of M2 macrophages. Modulating the imbalanced polarization of synovial macrophages was a possible mechanism of FHDP on attenuating synovitis and treating KOA.

Objective:To explore the application effect of a new type of simulated dermatologic surgical mold based on 3D printing in standardized residency training of dermatology.Methods:In this study, 35 residents in Department of Dermatology, The Second Affiliated Hospital of Guangzhou Medical University from January 2018 to May 2019 were randomly divided into two groups: a new mold group based on 3D printing ( n=18) and a traditional mold group ( n=17). Two groups of residents were examined by dermatologic biopsy on the mold, and the effect of teaching was evaluated by questionnaire survey. SPSS 22.0 was used for data analysis, and the measurement data was expressed by (means ± standard deviation). The comparison between the new mold group and the traditional mold group was made by two independent samples t test. Results:The scores of dermatologic biopsy examination of residents in the new mold group were higher than those in the traditional mold group, and the differences were statistically significant ( P<0.01); and the scores of the questionnaires for the teaching effect of the new mold group were higher than those of the traditional mold group, and the differences were statistically significant ( P<0.01). Conclusion:The new type of simulated dermatologic surgical mold based on 3D printing, which has been successfully applied in the practical training of residents, lays a solid foundation for the actual clinical operation and significantly improves the teaching effect, providing a broad application prospect.