1.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.
2.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.
3.Healthcare institution resilience and the influencing factors during infectious disease outbreaks
Yaqun FU ; Jiawei ZHANG ; Bing HAN ; Quan WANG ; Zheng ZHU ; Zhijie NIE ; Yiyang TAN ; Qing LIU ; Xiaoguang LI ; Jing GUO ; Rongmeng JIANG ; Li YANG
Journal of Peking University(Health Sciences) 2025;57(3):529-536
Objective:To analyze the association between healthcare workers mental health,institu-tional supplies and facilities,inter-organizational coordination during infectious disease outbreaks,and the healthcare institution resilience.Methods:An online questionnaire survey was conducted among the healthcare workforce from 146 institutions in Beijing from January 13,2023 to February 9,2023,and a total of 1 434 eligible respondents were included.The sample comprised 408 responses from tertiary hos-pitals,117 from secondary hospitals,and 909 from primary care institutions.The resilience indicator for healthcare institutions was defined as the degree to which medical services met patient demands,with in-fluencing factors including physical factors,such as material shortages and facility space adaptation or ex-pansion,organizational factors such as information sharing and patient referral,and psychological factors were evaluated using job satisfaction(extrinsic satisfaction,intrinsic satisfaction),burnout(emotional exhaustion,depersonalization,reduced personal accomplishment),and depression status.Ordered mul-ticlassification Logistic regression was used to examine the impact of various factors on the degree to which healthcare services met patient needs;additionally,demographic factors that might influence institutional resilience were controlled.Results:During the emergency response phase,93%of hospitals maintained the capacity to meet patient needs,though tertiary hospitals demonstrated significantly higher rates of service inadequacy(21.05%).Material shortages were reported across all institutions,with tertiary hos-pitals experiencing more frequent multi-item shortages.Inter-institutional collaboration patterns revealed substantial variation:87.50%of primary care facilities,42.86%of secondary hospitals,and 31.58%of tertiary hospitals.Healthcare workers across all levels reported mild depressive symptoms and moderate-to-severe burnout levels.Regression analysis showed high satisfaction(overall satisfaction β=0.04,ex-trinsic satisfaction β=0.06,and intrinsic satisfaction β=0.08),low degree of job burnout(emotional exhaustion β=-0.04,depersonalization β=-0.07 and reduced personal accomplishment β=0.01),low degree of depression(β=-0.06)were significantly associated with higher healthcare institution re-silience.In addition,material shortages were significantly associated with lower resilience,and renova-tion and expansion of treatment spaces,and information sharing,were all associated with higher resilience.Demographic factors(age,gender,marital status,educational background,etc.)had no sig-nificant impact on resilience.Conclusion:Mental health status significantly influences healthcare institu-tion resilience.As human resources constitute the core asset of healthcare institutions,strategic optimiza-tion of workforce allocation and psychological support interventions can effectively strengthen resilience.Moreover,healthcare institution resilience is positively impacted by orderly material supply chains,timely resource distribution,and adaptive reconfiguration of clinical spaces.Finally,facilitating information sharing also enhances institutional resilience.
4.Primary intracranial germ cell tumors in children: a clinical retrospective analysis of 126 cases
Juanyu XU ; Yixuan HE ; Xiaoguang QIU ; Chunde LI ; Yajie WANG ; Yaxian DENG
Chinese Pediatric Emergency Medicine 2025;32(6):454-459
Objective:To summarized the clinical characteristics of intracranial germ cell tumors(iGCTs)in children, with the ultimate goal of facilitating early tumor identification and guiding the prompt selection of appropriate treatment strategies.Methods:A retrospective analysis was conducted on pediatric patients with primary iGCTs admitted to Beijing Tiantan Hospital Affiliated to Capital Medical University between March 2021 and June 2022. Patient age, gender, clinical manifestations, tumor marker levels in cerebrospinal fluid (CSF) and blood, imaging features, and histopathological examination results were meticulously collected and statistically analyzed.Results:A total of 126 pediatric patients with iGCTs were included in the study, of which 86 cases (68.3%) were male,and 40 cases (31.7%) were female.The average age was (10.0 ± 3.5) years old. The mean age of onset was found between 6~14 years old(80.1%), with a male-to-female ratio of 2.2:1.The tumors were predominantly located in the sellar region (30.2%), basal ganglia (23.8%), and pineal region (19.8%). Notably, there were distinct differences in tumor location across different age groups: pineal region tumors were most prevalent in preschool children (71.4%), basal ganglia tumors were more common in school-age children (41.9%), and sellar region involvement was highest among adolescent patients(44.8%). Based on molecular marker analysis and biopsy diagnosis, 79 cases were classified as germinoma, 3 as teratoma, 2 as yolk sac tumor, 1 as choriocarcinoma, and 41 as mixed germinoma.All children underwent head CT and MRI examinations. Among them, 99 cases showed high-density lesions on CT,while 27 cases showed mixed density,including 39 cases of calcification and 35 cases of hydrocephalus.MRI revealed atrophy of the cerebral peduncle, caudate nucleus head, or cerebral cortex in 38 cases, involvement of the basal ganglia in 33 cases, and midbrain involvement in 5 cases.Blood β-human chorionic gonadotropin (β-HCG) and alpha-fetoprotein (AFP) levels were examined in all patients, while CSF tumor marker levels were analyzed in 103 cases. There were 76 cases with elevated β-HCG in blood and/or cerebrospinal fluid, and 24 cases with elevated AFP in blood and/or CSF.Additionally, all 86 male patients underwent genital ultrasound, revealed testicular microlithiasis in 12 cases and testicular cysts in 6 cases.Conclusion:The clinical presentation of iGCTs in pediatric patients exhibits significant heterogeneity in terms of epidemiology, classification, tumor location, and molecular markers. Notably, CSF β-HCG and AFP levels are equally crucial diagnostic indicators alongside blood tumor markers.Histological examination should be performed as early as possible in clinically suspected cases with negative tumor markers. Clinicians should remain vigilant for early imaging negative potential cases. In addition, male children with testicular microlithiasis or cysts should be closely followed up.
5.Application and outcome analysis of head-mounted display devices in endoscope-assisted breast augmentation surgery
Chinese Journal of Plastic Surgery 2025;41(8):833-839
Objective:To explore the application value of head-mounted display (HMD) devices in endoscope-assisted breast augmentation surgery.Methods:This prospective study enrolled female patients who underwent breast augmentation at the Department of Plastic Surgery, Tianjin Meilai Medical Cosmetology Hospital from March to December 2024. According to admission time, patients were divided into a control group and an observation group. The control group underwent endoscope-assisted breast augmentation, while the observation group received the same procedure with the addition of an HMD device. Six surgeons compared the two groups in terms of operative time, intraoperative blood loss, visual analogue scale (VAS) scores at different time points, general comfort questionnaire (GCQ) scores, surgeons’ subjective evaluation scale scores, incidence of postoperative complications, and overall postoperative satisfaction rate based on patients’ subjective evaluations. Measurement data were analyzed by independent-samples t-test, and count data were analyzed by chi-square ( χ2) test. A P-value <0.05 was considered statistically significant. Results:A total of 60 female patients were included, with 30 cases in each group. Operative time and intraoperative blood loss were lower in the observation group than in the control group [(68.2±11.0) min vs. (76.3 ±13.6) min; (40.1±7.3) ml vs. (49.3±8.6) ml; both P<0.05]. Preoperative VAS scores showed no significant difference between the two groups [(7.88 ±1.28) points vs. (7.85 ±1.23) points, P> 0.05]. At 12 h and 24 h postoperatively, VAS scores in the observation group were significantly lower than those in the control group [(5.7 ±1.1) points vs. (6.4 ±1.2) points; (4.5 ±1.0) points vs. (5.3±1.0) points; both P<0.05]. Preoperative GCQ scores showed no significant difference [(9.6±2.2) points vs. (9.6±2.2) points, P>0.05], while postoperative GCQ scores and surgeons’ subjective evaluation scores were higher in the observation group [(16.3±3.8) points vs. (13.2 ±2.7) points; (89.7 ±11.6) points vs. (82.7 ±10.6) points; (90.3±10.5) points vs. (83.0±12.0) points; all P<0.05]. Regarding postoperative complications, the incidence of postoperative bleeding was higher in the control group [13.3% (4/30) vs. 0 (0/30), P <0.05], while the differences in hematoma (6.7% vs. 3.3%), poor incision healing (10.0% vs. 6.7%), and implant displacement (10.0% vs. 6.7%) were not statistically significant (all P>0.05). The postoperative satisfaction rate was 96.7% (29/30) in the observation group and 76.7% (23/30) in the control group, with no statistically significant difference ( P>0.05). Conclusion:The introduction of HMD devices in endoscope-assisted breast augmentation surgery can effectively expand the visualization of the operative field, shorten operative time, reduce intraoperative blood loss, alleviate early postoperative pain, and improve the surgeon’s intraoperative convenience.
6.Application of transnasal endoscopic approach for clipping the paraclival internal carotid artery in skull base surgery
Haiyan LI ; Pingping HU ; Minggang SHI ; Xu WANG ; Yanguo SHANG ; Xiaoguang TONG ; Gang LIU ; Guodong FENG ; Xiang ZHAI
Chinese Journal of Otorhinolaryngology Head and Neck Surgery 2025;60(10):1291-1297
Objective:To evaluate the feasibility and outcomes of transnasal endoscopic clipping of the paraclival internal carotid artery (ICA) in skull base surgery.Methods:The paraclival ICA was anatomically dissected in cadaveric head specimens. The clinical data of 15 patients with skull base lesions involving the ICA who admitted to the Department of Otorhinolaryngology Head and Neck Surgery at Tianjin Huanhu Hospital from January 2021 to December 2023 were retrospectively analyzed. Among them, 4 patients underwent transnasal endoscopic clipping of the paraclival ICA and concurrent lesion resection. The surgical methods were summarized, and the key points and indications of this technique were analyzed.Results:Intraoperative clipping of the ICA was successful and hemostatic in all 4 patients. Postoperatively, 3 patients had no complications, while 1 patient developed delayed ischemic cerebral infarction. Two patients were cured, 1 patient was maintained on immunotherapy, and 1 patient died. During follow-up, the clip was in situ in 1 patient, had detached in another, and was obscured by temporal muscle coverage in the remaining 2 patients.Conclusions:Transnasal endoscopic clipping of the paraclival ICA represents a potential option for managing the ICA in skull base surgery. However, it carries significant risks and limitations, mandating careful patient selection based on specific circumstances.
7.Research progresses in cryoablation of bladder cancer
Chinese Journal of Interventional Imaging and Therapy 2025;22(4):288-291
Interventional therapy promises a novel treatment for muscle invasive bladder cancer(MIBC),but the long-term effect is limited,and combination therapy is necessary for MIBC.Cryoablation kills tumors by freezing tissue with ultra-low temperature,but its safety and efficacy for MIBC remains unclear.The research progresses in cryoablation for bladder cancer animal models and human MIBC were reviewed in this article.
8.The therapeutic effect of modified lizhong decoction on gastric and duodenal ulcers of spleen and stomach cold deficiency type and its impact on gastric function and inflammatory mediators
Xiaoguang WEI ; Quan WANG ; Wenjuan SUN ; Ling CHENG ; Lei MA
The Journal of Practical Medicine 2025;41(23):3773-3779
Objective To investigate the therapeutic effects of modified Lizhong Decoction on gastric and duodenal ulcers(GDU)of the spleen-stomach cold deficiency type,as well as its influence on gastric function and inflammatory mediators.Methods From April 2023 to May 2025,patients diagnosed with gastric dyspepsia of the spleen and stomach cold deficiency type at Nanyang First People's Hospital were randomly assigned to either the Western medicine group(n=53)or the combined therapy group(n=53).The Western medicine group received oral rabeprazole sodium enteric-coated tablets and sucralfate suspension,while the combined therapy group received the same Western medication regimen plus modified Lizhong Decoction.Both groups underwent a 6-week treatment course.Outcomes including clinical efficacy after 6 weeks,gastric mucosal morphology scores,gastric function,levels of inflammatory mediators,mucosal repair-related factors,oxidative stress markers,quality of life before and after treatment,and treatment safety were compared between the two groups.Results The total effective rate in the combined group after 6 weeks of treatment was significantly higher than that in the Western medicine group(P<0.05).After 6 weeks of treatment,both groups showed reduced mucosal thickness,inflammatory cell infiltration,glandular density scores,and decreased serum levels of cholecystokinin(CCK),motilin(MTL),gastrin(GAS),interleukin-6(IL-6),tumor necrosis factor-α(TNF-α),nuclear factor-κB(NF-κB),and malondialdehyde(MDA)compared to baseline,with greater reductions observed in the combined group(P<0.05).Additionally,serum levels of calcitonin gene-related peptide(CGRP),trefoil factor 1(TFF1),epidermal growth factor(EGF),epidermal growth factor receptor(EGFR),and superoxide dismutase(SOD),as well as quality-of-life scores across multiple domains,were significantly increased from baseline in both groups,with the combined group showing superior improvements(P<0.05).During the treatment period,the incidence of adverse reactions was 11.32%in the combined group and 5.66%in the Western medicine group,with no statistically significant difference between the two groups(P>0.05).Conclusion Modified Lizhong Decoction demonstrated a definite therapeutic effect on GDU of the spleen and stomach cold deficiency type,effectively improving gastric mucosal morphology,enhancing gastric function,suppressing inflammatory responses and oxidative stress,promoting the secretion of mucosal repair-related factors,improving patients'quality of life,and exhibiting favorable safety.
9.Ethical considerations in embryo disposition cases
Xiaoguang SHAO ; Hang DU ; Xiuxia WANG
Chinese Journal of Reproduction and Contraception 2025;45(4):346-348
One of the important goals of assisted reproductive technology management is the safety of offspring. When the needs of patients conflict with the management of assisted reproductive technology, reproductive ethical problems arise. The storage and use of frozen embryos is a part of the management of assisted reproductive technology. When the patient has a conflict in the storage and use of frozen embryos, a small number of court decisions are consistent with the national management measures, but the vast majority of court decisions give the patient the right to ownership of frozen embryos, ruling that the patient has the right to custody and disposal, and the hospital will be difficult to implement embryo cryopreservation and management by national laws and regulations. In this paper, we review the ethical considerations in embryos, in order to provide beneficial references for embryo management in assisted reproductive technology.
10.Primary intracranial germ cell tumors in children: a clinical retrospective analysis of 126 cases
Juanyu XU ; Yixuan HE ; Xiaoguang QIU ; Chunde LI ; Yajie WANG ; Yaxian DENG
Chinese Pediatric Emergency Medicine 2025;32(6):454-459
Objective:To summarized the clinical characteristics of intracranial germ cell tumors(iGCTs)in children, with the ultimate goal of facilitating early tumor identification and guiding the prompt selection of appropriate treatment strategies.Methods:A retrospective analysis was conducted on pediatric patients with primary iGCTs admitted to Beijing Tiantan Hospital Affiliated to Capital Medical University between March 2021 and June 2022. Patient age, gender, clinical manifestations, tumor marker levels in cerebrospinal fluid (CSF) and blood, imaging features, and histopathological examination results were meticulously collected and statistically analyzed.Results:A total of 126 pediatric patients with iGCTs were included in the study, of which 86 cases (68.3%) were male,and 40 cases (31.7%) were female.The average age was (10.0 ± 3.5) years old. The mean age of onset was found between 6~14 years old(80.1%), with a male-to-female ratio of 2.2:1.The tumors were predominantly located in the sellar region (30.2%), basal ganglia (23.8%), and pineal region (19.8%). Notably, there were distinct differences in tumor location across different age groups: pineal region tumors were most prevalent in preschool children (71.4%), basal ganglia tumors were more common in school-age children (41.9%), and sellar region involvement was highest among adolescent patients(44.8%). Based on molecular marker analysis and biopsy diagnosis, 79 cases were classified as germinoma, 3 as teratoma, 2 as yolk sac tumor, 1 as choriocarcinoma, and 41 as mixed germinoma.All children underwent head CT and MRI examinations. Among them, 99 cases showed high-density lesions on CT,while 27 cases showed mixed density,including 39 cases of calcification and 35 cases of hydrocephalus.MRI revealed atrophy of the cerebral peduncle, caudate nucleus head, or cerebral cortex in 38 cases, involvement of the basal ganglia in 33 cases, and midbrain involvement in 5 cases.Blood β-human chorionic gonadotropin (β-HCG) and alpha-fetoprotein (AFP) levels were examined in all patients, while CSF tumor marker levels were analyzed in 103 cases. There were 76 cases with elevated β-HCG in blood and/or cerebrospinal fluid, and 24 cases with elevated AFP in blood and/or CSF.Additionally, all 86 male patients underwent genital ultrasound, revealed testicular microlithiasis in 12 cases and testicular cysts in 6 cases.Conclusion:The clinical presentation of iGCTs in pediatric patients exhibits significant heterogeneity in terms of epidemiology, classification, tumor location, and molecular markers. Notably, CSF β-HCG and AFP levels are equally crucial diagnostic indicators alongside blood tumor markers.Histological examination should be performed as early as possible in clinically suspected cases with negative tumor markers. Clinicians should remain vigilant for early imaging negative potential cases. In addition, male children with testicular microlithiasis or cysts should be closely followed up.

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