1.Mechanisms of Shenqi Wenfei Prescription in Intervening in Chronic Obstructive Pulmonary Disease in Rats Based on ROS/TXNIP/NLRP3 Signaling Pathway
Di WU ; Mengyao SHI ; Lu ZHANG ; Tong LIU ; Jiabing TONG ; Cheng YANG ; Zegeng LI
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(3):78-87
ObjectiveTo investigate the effects and underlying mechanisms of Shenqi Wenfei prescription (SQWF) on chronic obstructive pulmonary disease (COPD). MethodsA rat model of COPD with lung Qi deficiency was established using lipopolysaccharide (LPS) combined with cigarette smoke. Forty-eight SD rats were randomly divided into a blank group, a model group, low-, medium-, and high-dose SQWF groups (2.835, 5.67, 11.34 g·kg-1), and a Yupingfeng group (1.35 g·kg-1). Drug administration began on day 29 after modeling and continued for 2 weeks. The general condition of the rats was observed, and the lung function in each group was assessed. Hematoxylin-eosin (HE) staining was used to observe pathological changes in lung tissue. The proportion of inflammatory cells in bronchoalveolar lavage fluid (BALF) was measured. Apoptosis in lung tissue was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. The release level of lactate dehydrogenase (LDH) in BALF was detected by a microplate assay. Reactive oxygen species (ROS) levels in lung tissue were detected using fluorescent probes. The levels of malondialdehyde (MDA), total superoxide dismutase (SOD), and reduced glutathione (GSH) in BALF were measured by biochemical methods. Ultrastructural changes in lung cells were observed via transmission electron microscopy. Double immunofluorescence staining was performed to detect the expression of thioredoxin-interacting protein (TXNIP) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) in lung tissue. Western blot analysis was used to detect the protein expression of TXNIP, NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), cysteinyl aspartate-specific protease-1 (Caspase-1), Caspase-1 p20, gasdermin D (GSDMD), GSDMD N-terminal active fragment (GSDMD-N), interleukin-1β (IL-1β), and IL-18 in lung tissue. Serum IL-1β and IL-18 levels were measured by ELISA. ResultsCompared with the blank group, the model group showed lassitude, fatigue, tachypnea, and audible phlegm sounds, and lung function significantly declined (P0.01). Pulmonary emphysema and inflammatory cell infiltration were obvious. The level of inflammatory cells in BALF increased significantly (P0.05). The number of TUNEL-positive cells increased (P0.01). Levels of LDH, ROS, and MDA in BALF increased significantly (P0.01), while GSH and SOD activities decreased significantly (P0.01). Lung tissue cells showed irregular morphology, swollen mitochondria, disrupted cell membranes, and abundant vesicles, i.e., pyroptotic bodies. Protein levels of TXNIP, NLRP3, ASC, Caspase-1, Caspase-1 p20, GSDMD, GSDMD-N, IL-1β, and IL-18 in lung tissue were significantly elevated (P0.01), and serum IL-1β and IL-18 levels also increased significantly (P0.01). Compared with the model group, each medication group showed alleviation of qi deficiency symptoms and improved lung function (P0.01). Pulmonary emphysema and inflammatory cell infiltration were reduced. Inflammatory cell levels decreased (P0.05). The number of TUNEL-positive cells decreased significantly (P0.01). Levels of LDH, ROS, and MDA decreased significantly (P0.05), while GSH and SOD activities significantly increased (P0.01). Morphological and structural damage in lung tissue was improved to varying degrees. Protein levels of TXNIP, NLRP3, ASC, Caspase-1, Caspase-1 p20, GSDMD, GSDMD-N, IL-1β, and IL-18 in lung tissue significantly decreased (P0.01), and serum IL-1β and IL-18 levels also decreased significantly (P0.05). ConclusionSQWF can improve lung function and alleviate inflammatory responses in COPD rats. Its mechanism may be related to regulating the ROS/TXNIP/NLRP3 pathway and inhibiting pyroptosis.
2.Mechanisms of Shenqi Wenfei Prescription in Intervening in Chronic Obstructive Pulmonary Disease in Rats Based on ROS/TXNIP/NLRP3 Signaling Pathway
Di WU ; Mengyao SHI ; Lu ZHANG ; Tong LIU ; Jiabing TONG ; Cheng YANG ; Zegeng LI
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(3):78-87
ObjectiveTo investigate the effects and underlying mechanisms of Shenqi Wenfei prescription (SQWF) on chronic obstructive pulmonary disease (COPD). MethodsA rat model of COPD with lung Qi deficiency was established using lipopolysaccharide (LPS) combined with cigarette smoke. Forty-eight SD rats were randomly divided into a blank group, a model group, low-, medium-, and high-dose SQWF groups (2.835, 5.67, 11.34 g·kg-1), and a Yupingfeng group (1.35 g·kg-1). Drug administration began on day 29 after modeling and continued for 2 weeks. The general condition of the rats was observed, and the lung function in each group was assessed. Hematoxylin-eosin (HE) staining was used to observe pathological changes in lung tissue. The proportion of inflammatory cells in bronchoalveolar lavage fluid (BALF) was measured. Apoptosis in lung tissue was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. The release level of lactate dehydrogenase (LDH) in BALF was detected by a microplate assay. Reactive oxygen species (ROS) levels in lung tissue were detected using fluorescent probes. The levels of malondialdehyde (MDA), total superoxide dismutase (SOD), and reduced glutathione (GSH) in BALF were measured by biochemical methods. Ultrastructural changes in lung cells were observed via transmission electron microscopy. Double immunofluorescence staining was performed to detect the expression of thioredoxin-interacting protein (TXNIP) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) in lung tissue. Western blot analysis was used to detect the protein expression of TXNIP, NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), cysteinyl aspartate-specific protease-1 (Caspase-1), Caspase-1 p20, gasdermin D (GSDMD), GSDMD N-terminal active fragment (GSDMD-N), interleukin-1β (IL-1β), and IL-18 in lung tissue. Serum IL-1β and IL-18 levels were measured by ELISA. ResultsCompared with the blank group, the model group showed lassitude, fatigue, tachypnea, and audible phlegm sounds, and lung function significantly declined (P0.01). Pulmonary emphysema and inflammatory cell infiltration were obvious. The level of inflammatory cells in BALF increased significantly (P0.05). The number of TUNEL-positive cells increased (P0.01). Levels of LDH, ROS, and MDA in BALF increased significantly (P0.01), while GSH and SOD activities decreased significantly (P0.01). Lung tissue cells showed irregular morphology, swollen mitochondria, disrupted cell membranes, and abundant vesicles, i.e., pyroptotic bodies. Protein levels of TXNIP, NLRP3, ASC, Caspase-1, Caspase-1 p20, GSDMD, GSDMD-N, IL-1β, and IL-18 in lung tissue were significantly elevated (P0.01), and serum IL-1β and IL-18 levels also increased significantly (P0.01). Compared with the model group, each medication group showed alleviation of qi deficiency symptoms and improved lung function (P0.01). Pulmonary emphysema and inflammatory cell infiltration were reduced. Inflammatory cell levels decreased (P0.05). The number of TUNEL-positive cells decreased significantly (P0.01). Levels of LDH, ROS, and MDA decreased significantly (P0.05), while GSH and SOD activities significantly increased (P0.01). Morphological and structural damage in lung tissue was improved to varying degrees. Protein levels of TXNIP, NLRP3, ASC, Caspase-1, Caspase-1 p20, GSDMD, GSDMD-N, IL-1β, and IL-18 in lung tissue significantly decreased (P0.01), and serum IL-1β and IL-18 levels also decreased significantly (P0.05). ConclusionSQWF can improve lung function and alleviate inflammatory responses in COPD rats. Its mechanism may be related to regulating the ROS/TXNIP/NLRP3 pathway and inhibiting pyroptosis.
3.Epidemiological characteristics and influencing factors of severe fever with thrombocytopenia syndrome in Zhejiang Province
LÜ ; Jing ; XU Xinying ; QIAO Yingyi ; SHI Xinglong ; YUE Fang ; LIU Ying ; CHENG Chuanlong ; ZHANG Yuqi ; SUN Jimin ; LI Xiujun
Journal of Preventive Medicine 2026;38(1):10-14
Objective:
To analyze the epidemiological characteristics and influencing factors of severe fever with thrombocytopenia syndrome (SFTS) in Zhejiang Province from 2019 to 2023, so as to provide the reference for strengthening SFTS prevention and control.
Methods:
Data on laboratory-confirmed SFTS cases in Zhejiang Province from 2019 to 2023 were collected through the Infectious Disease Reporting Information System of Chinese Disease Prevention and Control Information System. Meteorological data, geographic environment and socioeconomic factors during the same period were collected from the fifth-generation European Centre for Medium-Range Weather Forecasts, Geospatial Data Cloud, and Zhejiang Statistical Yearbook, respectively. Descriptive epidemiological methods were used to analyze the epidemiological characteristics of SFTS from 2019 to 2023, and a Bayesian spatio-temporal model was constructed to analyze the influencing factors of SFTS incidence.
Results:
A total of 578 SFTS cases were reported in Zhejiang Province from 2019 to 2023, with an annual average incidence of 0.23/105. The peak period was from May to July, accounting for 52.60%. There were 309 males and 269 females, with a male-to-female ratio of 1.15∶1. The cases were mainly aged 50-<80 years, farmers, and in rural areas, accounting for 82.53%, 77.34%, and 75.43%, respectively. Taizhou City and Shaoxing City reported more SFTS cases, while Shaoxing City and Zhoushan City had higher annual average incidences of SFTS. The Bayesian spatio-temporal interaction model showed good goodness of fit. The results showed that mean temperature (RR=1.626, 95%CI: 1.111-2.378) and mean wind speed (RR=1.814, 95%CI: 1.321-2.492) were positively correlated with SFTS risk, while altitude (RR=0.432, 95%CI: 0.230-0.829) and population density (RR=0.443, 95%CI: 0.207-0.964) were negatively correlated with SFTS risk.
Conclusions
SFTS in Zhejiang Province peaks from May to July. Middle-aged and elderly people and farmers are high-risk populations. Taizhou City, Shaoxing City, and Zhoushan City are high-incidence areas. Mean temperature, mean wind speed, altitude, and population density can all affect the risk of SFTS incidence.
4.Analysis of the hydration status and related factors of boarding students in a rural primary school in Guangxi
ZHANG Yaning*, CHENG Shuai, XIA Yunting, ZHANG Na, LI Hongxing
Chinese Journal of School Health 2026;47(1):37-41
Objective:
To understand the hydration status and related factors of rural boarding primary school students, so as to provide a scientific basis for drinking water health intervention for primary school students.
Methods:
In November 2023, a convenience sampling approach was employed to conduct a hydration status survey among 144 boarding students in grades 5 and 6 of a rural primary school in Guangxi. The Duplicate meal method and weighing method were utilized to measure the food derived water intake over three consecutive days. Urine osmolarity of students was measured on site for three days, and a simple physical examination was also carried out. A self administered questionnaire was used to investigate students drinking water literacy, daily water intake, and physical activity levels. Meanwhile, a drinking water literacy survey was conducted among 21 substitute teachers and 144 parents of the boarding students in grades 5 and 6. Logistic regression was used to identify factors associated with students hydration status.
Results:
The median daily total water intake of students was 2 043.55 mL, and 54.86% of the students did not reach the recommended Adequate Intake (AI). The median food derived water intake was 1 149.24 mL, accounting for 53.94% of the total water intake. Univariate analysis revealed that the daily drinking frequency, daily water intake, and food derived water intake of students were related factors of hydration status ( β =-1.60, -1.01, -0.00, all P <0.05). Multivariate Logistic regression analysis showed that primary school students with a daily drinking frequency of ≥7 times were more likely to maintain an adequate hydration status ( OR =0.28, 95% CI =0.09-0.93, P <0.05).
Conclusions
The water intake from food is the main source of water in the body for boarding primary school students in a certain rural school in Guangxi. Primary school students should increase their water intake frequency appropriately to maintain an adequate hydration status.
5.Qualitative and Quantitative Analysis of Chemical Constituents in Gualou Niubangtang by UPLC-Q-TOF-MS/MS and HPLC
Yiyi ZHANG ; Jing YANG ; Yuqing CHENG ; Huimin GAO ; Jin QIN ; Li YAO ; Xiyang DU ; Raorao LI
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(6):179-187
ObjectiveThis paper aims to clarify the material basis of Gualou Niubangtang and establish a quantitative analysis method for its main constituents, providing a reference for the overall quality control of this preparation. MethodsThe constituents in the formula were systematically characterized based on ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS). Identification was performed by matching with the UNIFI 9.6 software and utilizing database platforms such as PubChem, ChemicalBook, and ChemSpider, combined with relevant literature reports. A quantitative analysis method for the seven main constituents in Gualou Niubangtang was established by using high performance liquid chromatography (HPLC). ResultsUPLC-Q-TOF-MS/MS analysis identified 155 constituents, including 69 flavonoids, 36 terpenoids, 23 phenylpropanoids, 8 phenylethanoid glycosides, and 19 other types of constituents. In the established quantitative analysis method, the seven main constituents showed good linearity within their respective linear ranges. The precision, repeatability, stability, and spike recovery all met the required standards. The results showed that the content ranges of geniposide, liquiritin, hesperidin, arctiin, baicalin, oroxylin A-7-O-β-D-glucuronide, and wogonoside in 15 batches of Gualou Niubangtang were 13.67-21.25, 1.20-7.64, 5.45-7.45, 22.97-33.51, 29.95-39.07, 2.58-4.80, and 6.56-9.31 mg·g-1, respectively. ConclusionThis study successfully characterizes and attributes multi-category constituents in Gualou Niubangtang, clarifying that its material basis is primarily composed of flavonoids, terpenoids, phenylethanoid glycosides, and phenylpropanoids. Furthermore, it enables the quantification of seven constituents within the formula. This work lays a foundation for research on the quality control, action mechanism, and clinical application of this formula.
6.Serological characteristics of individuals with hepatitis C virus/hepatitis B virus overlapping infection
Yanfei CUI ; Xia HUANG ; Chao ZHANG ; Yingjie JI ; Song QING ; Yuanjie FU ; Jing ZHANG ; Li LIU ; Yongqian CHENG
Journal of Clinical Hepatology 2026;42(1):74-79
ObjectiveTo investigate the status of overlapping hepatitis B virus (HBV) infection in patients with chronic hepatitis C virus (HCV) infection and the serological characteristics of such patients. MethodsA total of 8 637 patients with HCV infection who were hospitalized from January 1, 2010 to December 31, 2020 and had complete data of HBV serological markers were enrolled, and the composition ratio of patients with overlapping HBV serological markers was analyzed among the patients with HCV infection. The patients were divided into groups based on age and year of birth, and serological characteristics were analyzed, and the distribution of HBV-related serological characteristics were analyzed across different HCV genotypes. ResultsThe patients with HCV/HBV overlapping infection accounted for 5.85%, and the patients with previous HBV infection accounted for 48.10%; the patients with protective immunity against HBV accounted for 14.67%, while the patients with a lack of protective immunity against HBV accounted for 31.39%. The patients were divided into groups based on age: in the 0 — 17 years group, the patients with protective immunity against HBV accounted for 61.41% (304 patients); the 18 — 44 years group was mainly composed of patients with previous HBV infection (698 patients, 37.31%), the 45 — 59 years group was predominantly composed of patients with previous HBV infection (1 945 patients, 50.38%), and the ≥60 years group was also predominantly composed of patients with previous HBV infection (1 486 patients, 61.66%). The patients were divided into groups based on the year of birth: in the pre-1992 group, the patients with previous HBV infection accounted for 51.63% (4 112 patients); in the 1992 — 2005 group, the patients with protective immunity against HBV accounted for 54.72% (168 patients); in the post-2005 group, the patients with protective immunity against HBV accounted for 64.38% (235 patients). In this study, 6 301 patients underwent HCV genotype testing: the patients with genotype 1b accounted for the highest proportion of 51.71% (3 258 patients), followed by those with genotype 2a (1 769 patients, 28.07%), genotype 3b (63 patients, 1.00%), genotype 3a (10 patients, 0.16%), genotype 4 (21 patients, 0.33%), and genotype 6a (5 patients, 0.08%). ConclusionWith the implementation of hepatitis B planned vaccination program in China, there has been a significant reduction in the proportion of patients with previous HBV infection among the patients with HCV/HBV overlapping infection, but there is still a relatively high proportion of patients with a lack of protective immunity against HBV.
7.Regulatory Mechanisms of miRNA in Hepatocellular Carcinoma and Current Status of Traditional Chinese Medicine Intervention: A Review
Shiyi LI ; Hao CHENG ; Chunyan JI ; Jun SUN ; Juan XUE
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(11):323-332
Hepatocellular carcinoma(HCC), as one of the common malignant tumours, has seen a continuous rise in incidence and mortality worldwide, posing a serious threat to human health. However, traditional treatments have certain limitations, therefore, the exploration of new therapeutic strategies is particularly urgent. In recent years, with in-depth research on the regulatory mechanisms of microRNA(miRNA) in tumour occurrence and development, it has become new targets for HCC diagnosis and treatment. As a traditional treatment method, Chinese medicine, due to its multi-component, multi-pathway, and multi-target overall regulatory characteristics, shows broad prospects in treating HCC by regulating miRNAs. Accordingly, this paper reviews recent studies on the role of miRNAs in HCC and research advances in traditional Chinese medicine interventions, finding that various miRNAs play key roles in HCC cell cycle regulation, proliferation and apoptosis, invasion and metastasis, immune microenvironment, and drug resistance. It summarises how active ingredients, extracts, medicinal pairs, and formulas of Chinese medicine act on specific miRNAs to regulate their downstream target gene expression, affecting the malignant behaviour of HCC cells and exerting anti-cancer effects. This study aims to provide a theoretical basis for miRNAs as potential biomarkers and therapeutic targets for HCC, as well as to offer new ideas for developing miRNA-based targeted Chinese medicine therapies.
8.Dilemmas and challenges for parasitology teachers at shortage of clinicalmedical sciences knowledge background in medical colleges and universities
Su HAN ; Yang CHENG ; Chao DENG ; Youyi LIU ; Yuhong LI
Chinese Journal of Schistosomiasis Control 2026;38(1):69-73
Medical parasitology, as a course bridging basic medical sciences and clinical medicine, has an important disciplinary value in the medical education system. This study investigated the composition of parasitology teachers from multiple medical colleges and universities across China. The results showed that there was a significant difference in the proportion of teachers with clinical medicine background knowledge, and there was common dilemma that there were insufficient clinical medicine knowledge reserves among teachers in some medical colleges and universities, who encountered severe teaching challenges. Based on this issue, this study constructed a basic-clinical medicine collaborative problem-based learning (PBL) teaching model. This model integrated theoretical teaching, case analyses, and experimental operations, and combined transdisciplinary team building and multidimensional teacher training, which significantly improved the clinical teaching capability among parasitology teachers, and effectively compensated the impact of insufficient clinical medicine knowledge reserves on teaching. Following teaching reform, students' scores significantly improved, and their case analysis capability enhanced. This study provides a practical path to address the shortage of clinical medicine background knowledge among parasitology teachers, which facilitates the progress of educational reform of medical parasitology and improvement of teaching quality.
9.Association of mixed exposure to lithium, vanadium, uranium, and bismuth in early pregnancy with gestational weight gain
Jiao LI ; Qi LI ; Shuang CHENG ; Jiayi SONG ; Xiaohui GUO ; Xiang WANG ; Di CHENG ; Kefeng FAN ; Ju WANG
Journal of Environmental and Occupational Medicine 2026;43(4):475-484
Background Gestational weight gain is closely related to maternal and infant health outcomes. Pregnant women are simultaneously exposed to four metals—lithium (Li), vanadium (V), uranium (U), and bismuth (Bi)—through inhalation of fine particulate matter and consumption of contaminated food and water. Existing studies suggest that exposure to these metals may be associated with gestational weight gain. However, no study has yet explored the complex relationships between exposure to mixtures of these four metals and weight gain at different stages of pregnancy. Objective To investigate the associations between mixed exposure to Li, V, U, and Bi in early pregnancy and the average weekly gestational weight gain during both early pregnancy and mid-to-late pregnancy. Methods This prospective study recruited eligible women in early pregnancy from an obstetrics clinic of a tertiary hospital in Jinan, China, between September 2021 and July 2023. Pre-pregnancy weight, current weight (at 11+0 to 13+6 weeks of gestation), and spot urine samples (≥5.0 mL) were collected at enrollment. Urinary concentrations of Li, V, Bi, and U were determined using inductively coupled plasma mass spectrometry. Participants were followed up in late pregnancy (≥28 weeks of gestation) to collect information on physical activity via questionnaire; weight measurements at the last antenatal visit (35+0 to 37+6 weeks of gestation) were obtained from the hospital information system. After adjusting for covariates, multiple linear regression and generalized additive models were used to assess the associations of individual metals with weekly weight gain in early pregnancy and in mid-to-late pregnancy. Bayesian kernel machine regression (BKMR) and quantile-based g-computation (Qgcomp) were applied to evaluate the joint effects of the metal mixture exposure on weekly weight gain at the two gestational stages. Results A total of 313 pregnant women were included. The geometric means of urinary Li, V, U, and Bi concentrations were 37.07, 0.20, 0.06, and 0.04 μg·L−1, respectively; after creatinine adjustment, the corresponding values were 46.82, 0.25, 0.07, and 0.05 μg·g−1 (Cr). The mean weekly gestational weight gain was (0.19±0.25) kg in early pregnancy and (0.53 ± 0.18) kg in mid-to-late pregnancy. Both multiple linear regression and generalized additive models showed that urinary V concentration was positively associated with average weekly gestational weight gain in early pregnancy, while no significant associations were found for other metals or for gestational weight gain in mid-to-late pregnancy. In the BKMR model with early-pregnancy weight gain as the outcome, V had the strongest association [posterior inclusion probability (PIP)=0.773]. When other metals were fixed at their medians, V showed a positive non-linear association with the outcome. A significant single-metal effect of V and its interaction with Li were observed. Compared with the 50th percentile of the metal mixture, the average weekly weight gain in early pregnancy increased by 0.016 (95%CI: 0.003, 0.029) and 0.018 (95%CI: 0.001, 0.036) at the 60th and 65th percentiles, respectively; conversely, at the 25th percentile, it decreased by 0.026 (95%CI: 0.002, 0.050). Overall, the joint effect of the metal mixture on early- pregnancy weight gain showed an upward trend. In the BKMR model for mid-to-late pregnancy gestational weight gain, all PIPs were<0.5, and no significant single-metal effects, interactions, or joint effects were identified. Qgcomp results confirmed a positive association between the metal mixture and early-pregnancy weight gain (b=0.031, 95%CI: 0.010, 0.051; P<0.01), with V contributing the highest positive weight (0.71). No significant association was found for weight gain in mid-to-late pregnancy (b=0.007, P=0.339). Conclusion Higher levels of co-exposure to the Li, V, Bi, and U metal mixture during early pregnancy may be associated with increased average weekly weight gain in early pregnancy. Among these metals, V exhibits a predominant role and appears to interact with Li. No association is observed between early-pregnancy metal mixture exposure and average weekly gestational weight gain in mid-to-late pregnancy. These findings suggest that monitoring and managing metal exposure during early pregnancy may be crucial for the rational regulation of gestational weight gain.
10.Three-dimensional finite element analysis of molar distalization with clear aligners with different thicknesses and edges
Yanan CHENG ; Jiazhi YU ; Yinchang LIU ; Jie WU ; Tong YU ; Lu WANG ; Xiaoguang LI
Chinese Journal of Tissue Engineering Research 2026;30(2):310-318
BACKGROUND:One of the advantages of clear aligner treatment is molar distalization.However,tooth tilting movement and loss of anterior anchorage may occur during treatment.There are few studies on whether these problems can be improved by selecting clear aligners with different thicknesses and edges to improve the clinical treatment effect.OBJECTIVE:To analyze the control ability of clear aligners with different thickness and edges on the central incisor,lateral incisor,and second molar when pushing the maxillary second molar distally by three-dimensional finite element analysis.METHODS:Three-dimensional finite element analysis models of bilateral maxillary second molar distalization with clear aligner,maxillary dentition,periodontal ligament,and alveolar bone with different thicknesses and margins were established by Mimics,Geomagic Wrap,3-matic and SolidWorks software,respectively.There were 16 combinations of four thicknesses(0.4,0.5,0.625,and 0.75 mm)and four margins(scallop,straight,straight extension 2 mm and straight extension 4 mm).The data were imported into Ansys Workbench software for design and solution.The mean value,peak value and distribution of the periodontal ligament equivalent stress of the second molar,the equivalent stress and the maximum initial displacement of the second molar,and the control ability of each appliance on the second molar,central incisor,and lateral incisor were analyzed.RESULTS AND CONCLUSION:(1)The mean equivalent stress of periodontal ligament of the second molar,the equivalent stress of the second molar and the maximum initial displacement of the second molar increased with the extension of the appliance edge and the increase of the thickness of the appliance in the 16 groups of models.(2)When the thickness of appliances was the same,the maximum equivalent stress of the second molar in the linear appliance group was the highest,and the maximum equivalent stress of the second molar in the linear extended appliance group was greater than that in the scallop appliance group.When the edge of the appliance was the same,the periodontal ligament equivalent stress peak of the second molar increased with the increase of the thickness of the appliance.The equivalent stress distribution in the periodontal ligament of the second molar in the linear extendable appliance group was more uniform than that in the scallop appliance group and the linear appliance group.(3)When the thickness of the appliance was the same,the scallop-shaped appliance had the worst control on the second molar.When the edge of the appliance was the same,with the increase of the thickness of the appliance,the control of the second molar by the linear extender appliance was gradually stronger than that by the linear appliance.The control of the central incisor was stronger and more stable with the linear extended 2 mm appliance,while the control of the lateral incisor was stronger and more stable with the linear appliance.(4)The results showed that when using clear aligners to push molars distally,extending the edge of the appliance could improve the control of the molars and reduce the tilting movement of the teeth.The design of a straight extension margin of 2 mm for the central incisor and a straight edge for the lateral incisor can enhance the control of the anchorage incisor and reduce the labial inclination of the anterior teeth.


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