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 investigate the value of ¹⁸F-FDG PET/CT metabolic parameters in the prognostic assessment of nasopharyngeal cancer patients. Methods The clinical data and PET/CT metabolic parameters of 185 nasopharyngeal cancer patients were retrospectively analyzed. The collected parameters were SUV_max, MTV, TLG, total metabolic tumor volume (TMTV) and whole-body total lesion glycolysis (WTLG). The ROC curve was used to determine the optimal cut-off values of PET/CT metabolic parameters. Univariate and multivariate Cox regression models were used to screen the independent prognostic factors. Kaplan–Meier curves were used to analyze the survival differences. Results The results of univariate Cox regression analysis showed that age, pathologic type, WTLG, TMTV, MTV, and TLG were closely associated with OS and PFS; and SUV_max was associated with PFS (P<0.05). Multivariate Cox regression analysis results showed that age, TMTV, and WTLG were the independent prognostic factors for OS and PFS (P<0.05). The combination of WTLG with T/N staging (AUC=0.781 and 0.781) and TMTV with T/N staging (AUC=0.800 and 0.790) yielded greater predictive accuracy than that of WTLG and TMTV alone (AUC=0.724 and 0.719) or T/N staging (AUC=0.593 and 0.575). Conclusion TMTV and WTLG are important prognostic predictors of nasopharyngeal carcinoma. TLG and MTV of primary lesions are prognostic factors for patients’ PFS and OS. SUV_max has limited prognostic value. Systemic metabolic indexes (TMTV and WTLG), when combined with T/N staging, can optimize prognostic stratification.

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.

The emerging and re-emerging arthropod-borne infectious diseases pose a serious threat to global public health security. Field and laboratory studies of arthropods of medical importance are essential and critical for the prevention and control of arthropod-borne infectious diseases. Various institutions or universities in China have been conducting research in the field or laboratory study of arthropods of medical importance, but up to 2023, it is still lacking detailed biosafety guidelines or recommendations that can guide the related work for arthropods of medical importance. In order to proactively address potential biosafety issues in the field or laboratory activities related to arthropods of medical importance, improve the standardization of arthropod biosafety classification, operations, and protection, and ensure the safety of practitioners, an expert consensus on the biosafety recommendation of arthropods of medical importance in field and laboratory has been developed, aiming to guide the future work of arthropods and ensure the national biosafety and biosecurity of China.

Objective:To systematically evaluate the correlation between chronic periodontitis and postmenopausal osteoporosis (PMOP).Methods:Electronic searches were conducted on Cochrane Library, Pubmed, Embase, Ovid, CNKI, CBM, VIP, and WF databases to collect research literature on the correlation between chronic periodontitis and PMOP. The Newcastle Ottawa Scale (NOS) criteria were used to evaluate the quality of the included literature, and RevMan 5.3 software was used for meta-analysis. The outcome measures were clinical attachment loss (CAL), probing depth (PD), plaque index (PI), calculus index (CI), bleeding on probing (BOP), and simplified oral hygiene index (OHI-S).Results:A total of 16 articles were included, with a total of 1587 patients. Compared with the postmenopausal non osteoporosis group, the osteoporosis group showed significant abnormalities in CAL [standardized mean difference (SMD)=1.09, 95% CI: 0.62-1.57, P<0.001], PD(SMD=0.71, 95% CI: 0.28-1.14, P<0.001), PI(SMD=0.43, 95% CI: 0.29-0.56, P<0.001), and OHI-S(SMD=0.28, 95% CI: 0.22-0.35, P<0.001) indicators, as well as in BOP(SMD=0.01, 95% CI: -0.48-0.49, P=0.97) and GI(SMD=0.01, 95% CI: -0.48-0.49, P=0.97). At the level of 0.24 and 95% CI: -0.34 to 0.81, P=0.42, there was no statistically significant difference. Conclusions:Women with PMOP exhibit more significant changes in indicators such as CAL, PD, PI, and OHI-S, suggesting that postmenopausal women with osteoporosis are more likely to suffer from periodontitis.

The establishment of a traceability system for the entire industry chain of Chinese medicinal materials can enhance regional brand building,raise the quality awareness of medicinal material producers,standardize the production processes of Chinese medicinal materials,and ensure the production of high-quality medicinal materials.Sichuan Province has successfully implemented a provincial-level Traditional Chinese Medicine(TCM)tracing system that is interconnected across provinces,cities,and counties.This system enables the complete tracking of the entire supply chain,starting from seed and seedling cultivation,through planting and breeding,harvesting and processing,and finally to the production and distribution of decoction pieces in trade and medical institutions.This research provides a comprehensive overview of the progress made in establishing the Chinese herbal medicine traceability system in Sichuan Province.It analyzes the existing challenges faced by participating enterprises,such as the hierarchy of involvement,information integrity,and the overall impact of the system.Moreover,the paper presents valuable insights and suggestions for the further development of the Chinese herbal medicine traceability system in Sichuan Province.These recommendations focus on enhancing the traceability scope,improving service capabilities,promoting data sharing,and establishing standardized norms and guidelines.

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.

Objective:To explore the current status of surgery for portal hypertension to grasp current status and future development of surgery in China.Methods:This study is jointly sponsored by China Hepatobiliary & Pancreatic Specialist Alliance & Portal Hypertension Alliance in China (CHESS).Comprehensive surveying is conducted for basic domestic situations of surgery for portal hypertension, including case load, surgical approaches, management of postoperative complications, primary effects, existing confusion and obstacles, liver transplantation(LT), laparoscopic procedures and transjugular intrahepatic portosystemic shunt(TIPS), etc.Results:A total of 8 512 cases of portal hypertension surgery are performed at 378 hospitals nationwide in 2021.Splenectomy plus devascularization predominated(53.0%)and laparoscopy accounted for 76.1%.Primary goal is preventing rebleeding(67.0%) and 72.8% of hospitals used preventive anticoagulants after conventional surgery.And 80.7% of teams believe that the formation of postoperative portal vein thrombosis is a surgical dilemma and 65.3% of hospitals practiced both laparoscopy and TIPS.The major reasons for patients with portal hypertension not receiving LT are due to a lack of qualifications for LT(69.3%)and economic factors(69.0%).Conclusions:Surgery is an integral part of management of portal hypertension in China.However, it is imperative to further standardize the grasp of surgical indications, the handling of surgical operation and the management of postoperative complications.Moreover, prospective, multi-center randomized controlled clinical studies should be performed.

Objective:To investigate the types, incidences, and clinical characteristics of shock in polytrauma patients at different stages after polytrauma.Methods:A retrospective study was conducted on polytrauma patients admitted to multiple trauma centers from June 2020 to December 2021. The inclusion criteria were patients >18 years old and treated due to polytrauma. Exclusion criteria included an admission time of more than 48 h after trauma, a history of malignancy, or metabolic, consumptive, and immunological diseases. The early stage was defined as the period of ≤48 h after polytrauma, and the middle stage was defined as the period between 48 h and 14 days. The patient’s medical history, clinical manifestations, laboratory tests, imaging examination, injury severity score (ISS), and Glasgow coma scale (GCS) were collected. The types, incidences, and clinical characteristics of shock in different stages after polytrauma were analyzed, according to the diagnostic criteria of each type of shock. The differences between the groups were compared by Student’s t test, χ2 test or Mann-Whitney U test. Results:The incidence of the early and middle stage shock after polytrauma were 73.1% and 36.4%, respectively, with statistically significant difference between stages ( P<0.01). There were significant differences in the incidence of hypovolemic shock (83.6% vs. 28.4%), distributed shock (13.7% vs. 80.9%) and cardiogenic shock (3.5% vs. 6.6%) between stages (all P<0.05). The incidence of obstructive shock (8.4% vs. 9.7%, P>0.05) was similar between stages. The incidence of undifferentiated shock was 1.6% and 1.2%, respectively. There were 9.5% patients with multifactorial shock in the early stage and 14.4% in the middle stage. Totally 7 combinations of multifactorial shock were found in different stages after polytrauma. In the early stage, the combination of HS and DS accounted the highest ratio (42.3%) and followed by HS and OS for 28.8%. In the middle stage, the combination of HS and DS was the most common (48.6%) and followed by DS and OS (24.3%). Conclusions:The incidence of shock in polytrauma patients is high. Different types of shock can occur simultaneously or sequentially. Therefore a comprehensive resuscitation strategy is significant to improve the success rate of treatment.

Objective:To explore the application and practice of "flipped classroom" in the teaching of general surgery interns.Methods:A total of 20 internship groups (3 to 5 people in each group) were randomly selected from the general surgery practice group in the Department of General Surgery of the Second Clinical Medical College of North Sichuan Medical College. They were randomly divided into the flipped group (45 people) and the traditional group (40 people), with 10 subgroups in each group. The flipped group adopted the flipped classroom teaching mode (students' self-study by handing out materials before class, students and teachers' discussion in class, and students and teachers' evaluation after class), while the control group adopted the current conventional teaching mode (students' preview before class, teachers' explanation in class, and teachers' question answering after class). At the end of the teaching, a questionnaire was used to evaluate the participation and completion of each student. The teaching effect was evaluated by medical history collection and case analysis. The participation, completion, and teaching effect between the two groups were compared and analyzed. SPSS 23.0 software was used for t-test and Chi-square test. Results:The participation of the flipped group was better than that of the traditional group [(17.45±1.83) vs. (15.57±1.52)], and the difference was statistically significant ( P < 0.05). There was no statistically significant difference between the flipped group and the traditional group. There was no significant difference in medical history collection scores between the two groups. The case analysis of the flipped group was better than that of the traditional group [(87.30±6.06) vs. (81.50±5.88), P < 0.05]. The questionnaire shows that about 90% of the students think that flipped classroom can improve their interest in learning [96% (43/45)], improve their autonomous learning ability [89% (40/45)], and have better learning effect. At the same time, 78% (35/45) of students think that learning time is too long. Conclusion:The flipped classroom teaching model can improve the teaching participation of general surgery students, improve students' interest in learning, improve their self-learning ability, and improve students' thinking ability of medical record analysis.