1.Mechanical effect of mechanical wear of abutment screws on the Morse taper connection implant system:a three-dimensional finite element analysis
Chinese Journal of Tissue Engineering Research 2026;30(6):1375-1383
BACKGROUND:Abutment screw loosening is one of the most common mechanical complications in implant restoration.Mechanical wear,as a potential cause of thread loosening,warrants attention due to its impact on mechanical performance and long-term stability.However,studies on the mechanical effects of thread wear in abutment screws remain limited,and no definitive conclusions have been reached.OBJECTIVE:To investigate the effect of different degrees of mechanical wear on the spatial stress distribution of the Morse taper connection implant system,with a view to providing a theoretical basis for the clinical assessment of the long-term stability of dental implants.METHODS:Three-dimensional finite element models of Morse taper implants with central screw thread wear levels of 0,0.1,1,10,and 100 μm were established using SolidWorks software,and simulation analysis with Ansys Workbench software was performed.The implant models were inserted into artificial bone blocks(simulating type Ⅱ bone,with a cortical bone thickness of 2 mm on the outer layer and cancellous bone inside).An alternating load of 300 N in the buccolingual direction was applied at the centroid of the abutment(forming an angle of 30° with the long axis of the implant).The von Mises stress,principal stress,displacement,and fatigue life of the abutment,central screw,implant,and bone tissue in the five groups of models were analyzed.RESULTS AND CONCLUSION:(1)As the degree of mechanical wear on the central screw thread increased,the von Mises stress,principal stress,and strain in the implant and abutment also increased.The stress in the model was concentrated at the top of the implant,at the shoulder level of the implant,at the neck of the abutment,and at the bottom edge of the abutment.(2)Under moderate wear conditions(≥ 10 μm),the fatigue life of the implant system decreased by 30%,and the maximum von Mises stress of the central screw decreased by 37%,with the stress still primarily concentrated at the transition area between the head and the body of the central screw.(3)Under significant wear conditions(≥ 100 μm),the von Mises stress of the central screw decreased by 98%,with the stress concentrated at the screw head,and the fatigue life of the implant system decreased by 63%.Therefore,when the wear level of the central screw thread reaches ≥ 10 μm,the risk of screw loosening is significantly increased,and the fatigue life of the implant system is markedly reduced,warranting clinical attention.
2.Mechanical effect of mechanical wear of abutment screws on the Morse taper connection implant system:a three-dimensional finite element analysis
Chinese Journal of Tissue Engineering Research 2026;30(6):1375-1383
BACKGROUND:Abutment screw loosening is one of the most common mechanical complications in implant restoration.Mechanical wear,as a potential cause of thread loosening,warrants attention due to its impact on mechanical performance and long-term stability.However,studies on the mechanical effects of thread wear in abutment screws remain limited,and no definitive conclusions have been reached.OBJECTIVE:To investigate the effect of different degrees of mechanical wear on the spatial stress distribution of the Morse taper connection implant system,with a view to providing a theoretical basis for the clinical assessment of the long-term stability of dental implants.METHODS:Three-dimensional finite element models of Morse taper implants with central screw thread wear levels of 0,0.1,1,10,and 100 μm were established using SolidWorks software,and simulation analysis with Ansys Workbench software was performed.The implant models were inserted into artificial bone blocks(simulating type Ⅱ bone,with a cortical bone thickness of 2 mm on the outer layer and cancellous bone inside).An alternating load of 300 N in the buccolingual direction was applied at the centroid of the abutment(forming an angle of 30° with the long axis of the implant).The von Mises stress,principal stress,displacement,and fatigue life of the abutment,central screw,implant,and bone tissue in the five groups of models were analyzed.RESULTS AND CONCLUSION:(1)As the degree of mechanical wear on the central screw thread increased,the von Mises stress,principal stress,and strain in the implant and abutment also increased.The stress in the model was concentrated at the top of the implant,at the shoulder level of the implant,at the neck of the abutment,and at the bottom edge of the abutment.(2)Under moderate wear conditions(≥ 10 μm),the fatigue life of the implant system decreased by 30%,and the maximum von Mises stress of the central screw decreased by 37%,with the stress still primarily concentrated at the transition area between the head and the body of the central screw.(3)Under significant wear conditions(≥ 100 μm),the von Mises stress of the central screw decreased by 98%,with the stress concentrated at the screw head,and the fatigue life of the implant system decreased by 63%.Therefore,when the wear level of the central screw thread reaches ≥ 10 μm,the risk of screw loosening is significantly increased,and the fatigue life of the implant system is markedly reduced,warranting clinical attention.
3.The Effect of Fuzheng Huaji Formula (扶正化积方) for Chronic Hepatitis B on Reduction of the Incidence of Liver Cirrhosis and Hepatocellular Carcinoma:A Retrospective Cohort Study
Simiao YU ; Jiahui LI ; Jing JING ; Tingting HE ; Yongqiang SUN ; Liping WANG ; Aozhe ZHANG ; Xiaohe XIAO ; Xia DING ; Ruilin WANG
Journal of Traditional Chinese Medicine 2025;66(3):268-274
ObjectiveTo evaluate the clinical efficacy of Fuzheng Huaji Formula (扶正化积方) for chronic hepatitis B to reduce the incidence of liver cirrhosis and hepatocellular carcinoma. MethodsA retrospective cohort study was conducted, collecting medical records of 118 patients with chronic hepatitis B and 234 patients with hepatitis B-related cirrhosis who visited the hospital between January 1, 2014, and December 31, 2018. The use of Fuzheng Huaji Formula was designated as the exposure factor. Patients receiving antiviral treatment for hepatitis B without concurrent Fuzheng Huaji Formula therapy were included in the western medicine group, while those receiving antiviral treatment combined with Fuzheng Huaji Formula for a cumulative treatment lasting longer than 3 months were included in the combined treatment group. The follow-up observation period was five years. Kaplan-Meier survival analysis was used to assess the cumulative incidence of cirrhosis in patients with chronic hepatitis B and the cumulative incidence of hepatocellular carcinoma in patients with hepatitis B-related cirrhosis. Univariate and multivariate Cox regression analyses were employed to examine the factors influencing the occurrence of cirrhosis and hepatocellular carcinoma. ResultsAmong patients with chronic hepatitis B, there were 55 cases in the combined treatment group and 63 cases in the western medicine group; among patients with hepatitis B-related cirrhosis, there were 110 cases in the combined treatment group and 124 cases in the western medicine group. Five-year follow-up outcomes for chronic hepatitis B patients showed that the cumulative incidence of cirrhosis was 5.45% (3/55) in the combined treatment group and 17.46% (11/63) in the western medicine group, with a statistically significant difference between groups (Z = 2.003, P = 0.045). Five-year follow-up outcomes for hepatitis B-related cirrhosis patients showed that the cumulative incidence of hepatocellular carcinoma was 8.18% (9/110) in the combined treatment group and 22.58% (28/124) in the western medicine group, also showing a statistically significant difference (Z = 3.007, P = 0.003). Univariate and multivariate Cox regression analyses indicated that treatment with Fuzheng Huaji Formula is an independent protective factor in preventing the progression of chronic hepatitis B to cirrhosis and the progression of hepatitis B-related cirrhosis to hepatocellular carcinoma (P<0.05). ConclusionCombining Fuzheng Huaji Formula with antiviral therapy for hepatitis B can effectively intervene in the disease progression of chronic hepatitis B, reducing the incidence of cirrhosis and hepatocellular carcinoma.
4.Dispersion effect of bone cement after vertebroplasty using individualized unilateral external pedicle approach and bilateral pedicle approach
Lichuang ZHANG ; Wen YANG ; Guangjiang DING ; Peikun LI ; Zhongyu XIAO ; Ying CHEN ; Xue FANG ; Teng ZHANG
Chinese Journal of Tissue Engineering Research 2025;29(4):800-808
BACKGROUND:According to existing clinical studies,vertebroplasty treatment with both the external pedicle approach and the pedicle approach can improve the pain and quality of life of patients with spinal compression fractures.Compared with the pedicle approach,the external pedicle approach has a freer puncture angle,and good bone cement dispersion effect can be obtained by adjusting the puncture angle. OBJECTIVE:To compare the impact of vertebroplasty through individualized unilateral external pedicle approach and bilateral pedicle approach on the treatment of spinal compression fractures by quantifying the dispersion effect of bone cement. METHODS:A total of 80 patients with thoracolumbar compression fracture were divided into two groups by random number table method.The bilateral pedicle group(n=40)underwent vertebroplasty through a bilateral pedicle approach,while the unilateral external pedicle group(n=40)underwent individualized vertebroplasty through a unilateral external pedicle approach.Anteroposterior and lateral X-rays of the affected vertebrae from two groups of patients were photographed to assess effect and type of bone cement dispersion within 3 days after surgery.Visual analog scale score,tenderness threshold around fracture,and Oswestry dysfunction index were assessed before,1,7 days,and 1 month after surgery. RESULTS AND CONCLUSION:(1)Dispersion effect of bone cement in unilateral external pedicle group was better than that in bilateral pedicle group(P<0.001),and the amount of bone cement perfusion was higher than that in bilateral pedicle group(P<0.001).In the bilateral pedicle group,the bone cement dispersion types were mainly concentrated in type Ⅰ and type Ⅲ,while in the unilateral external pedicle group,the bone cement dispersion types were mainly concentrated in type I and type Ⅱ,and there was a significant difference in bone cement dispersion types between the two groups(P<0.001).(2)Postoperative visual analog scale scores and Oswestry disability index of both groups were lower than those before surgery(P<0.001),and postoperative tenderness threshold around fracture showed a trend of decreasing first and then increasing.At the same time point after treatment,there were no significant differences in visual analog scale score,Oswestry disability index,and tenderness threshold around fracture between the two groups(P>0.05).(3)The results indicate that individualized vertebroplasty via unilateral external pedicle approach can achieve better bone cement dispersion,and the treatment effect is consistent with the vertebroplasty via classical bilateral pedicle approach.
5.Five new triterpenoid saponins from the kernels of Momordica cochinchinensis
Ru DING ; Jia-qi WANG ; Yi-yang LUO ; Yong-long HAN ; Xiao-bo LI ; Meng-yue WANG
Acta Pharmaceutica Sinica 2025;60(2):442-448
Five saponins were isolated from the kernels of
6.Portal-venous phase CT peritumoral radiomics for predicting lymphovascular invasion of gastric adenocarcinoma
Xiao SUN ; Rui DING ; Li MA ; Wenling LI ; Huairong ZHANG ; Li ZHU
Chinese Journal of Medical Imaging Technology 2025;41(6):928-932
Objective To explore value of peritumoral radiomics models for predicting lymphovascular invasion(LVI)of gastric adenocarcinoma based on portal-venous phase enhanced CT images.Methods Totally 351 patients with gastric adenocarcinoma were collected and randomly divided into training set(n=246)and test set(n=105)at a ratio of 7∶3.ROI of tumors were manually delineated on portal-venous phase enhanced CT images,then radiomics features of tumoral areas and peritumoral areas(1,3 and 5 mm expanded from lesions)were extracted,respectively.Clinical-CT,tumoral and peritumoral(1 mm,3 mm,5 mm)radiomics and comprehensive model nomograms were established,and their predictive performances for LVI were compared.Calibration curve was used to evaluate the consistency between the predicted and actual LVI of gastric adenocarcinoma,while decision curve analysis(DCA)was used to assess the net clinical benefit of each model.Results The area under the curve of clinical-CT,tumoral,peritumoral(1 mm,3 mm,5 mm)radiomics models and the comprehensive model for predicting LVI in training set was 0.741,0.732,0.713,0.728,0.708 and 0.755,respectively,which in test set was 0.748,0.725,0.759,0.724,0.704 and 0.764,respectively.The comprehensive model demonstrated the highest prediction efficiency,also good calibration and clinical practicability.Conclusion Portal-venous phase CT peritumoral radiomics models could be used to predict LVI of gastric adenocarcinoma.Combining with CT features,tumoral and optimal peritumoral radiomics features could further improve predictive efficiency.
7.Guideline for the prevention of intraoperative acquired pressure injury in paraplegic patients with spinal cord injury (version 2025)
Aijun XU ; Shuixia LI ; Bo CHEN ; Mengyuan YE ; Lejiao LANG ; Ning NING ; Lin ZHANG ; Changqing LIU ; Zhonglan CHEN ; Weihu MA ; Weishi LI ; Xiaoning WANG ; Dongmei BIAN ; Jiancheng ZENG ; Xin WANG ; Yuan GAO ; Yaping CHEN ; Jiali CHEN ; Yun HAN ; Xiuting LI ; Yang ZHOU ; Xiaojing SU ; Qiong ZHANG ; Tianwen HUANG ; Ping ZHANG ; Hua LIN ; Xingling XIAO ; Ruifeng XU ; Fanghui DONG ; Bing HAN ; Luo FAN ; Yanling PEI ; Suyun LI ; Xiaoju TAN ; Rongchen GUO ; Yefang ZOU ; Xiaoyun HAN ; Junqin DING ; Yi WANG ; Shuhua DENG ; Jinli GUO ; Yinhua LIANG ; Yuan CEN ; Xiaoqin LIU ; Junru CHEN ; Haiyang YU ; Lunlan LI ; Ying REN ; Yunxia LI ; Jianli LU ; Ying YING ; Lan WEI ; Yin WANG ; Qinhong XU ; Yanqin ZHANG ; Yang LYU ; Shijun ZHANG ; Sui WENJIE ; Sanlian HU ; Shuhong YANG ; Guoqing LI ; Jingjing AN ; Baorong HE ; Leling FENG
Chinese Journal of Trauma 2025;41(6):530-541
Paraplegia caused by spinal cord injury is a serious neurological complication, for which surgery is currently the main treatment method. Due to different surgical approaches, patients are usually expected to maintain a passive prone position for a long time or switch between the supine and prone positions. Affected by multiple factors such as neurogenic sensory disorders, pathological changes in muscle tone and operative duration, the risk of intraoperative acquired pressure injury (IAPI) is significantly increased. Current clinical prevention strategies for IAPI in these patients predominantly focus on localized pressure relief during positioning, lacking systematic, standardized comprehensive prevention protocols or evidence-based guidelines. To address it, Department of Nursing, Orthopedics Branch, China International Exchange and Promotive Association for Medical and Health Care, Spinal Trauma Professional Committee, Orthopedics Branch, Chinese Medical Doctor Association, Nursing Group of Spine and Spinal Cord Professional Committee of Chinese Association of Rehabilitation Medicine organized experts in relevant fields to formulate Guideline for the prevention of intraoperative acquired pressure injury in paraplegic patients with spinal cord injury ( version 2025), based on evidence-based medical evidence and latest research results and clinical practice at home and abroad. Eleven recommendations were put forward from the aspects of preoperative risk assessment, intraoperative prevention strategies, postoperative handover and monitoring, and supportive mechanisms for IAPI prevention, aiming to standardize the prevention measures and management strategies of IAPI in paraplegic patients with spinal cord injury and accelerate the recovery of patients and improve the therapeutic effect.
8.Construction of a prediction model for muscular invasion in upper urinary tract urothelial carcinoma based on preoperative MRI features
Haonan CHEN ; Lingkai CAI ; Hongyuan DING ; Hao JI ; Tianxiao HONG ; Hao YU ; Qikai WU ; Chaoran ZHAO ; Xiao YANG ; Qiang CAO ; Xiancheng ZHAO ; Pengchao LI ; Qiang LYU
Chinese Journal of Urology 2025;46(9):661-668
Objective:To construct a nomogram based on preoperative MRI imaging features for the prediction of muscle-invasive upper urinary tract urothelial carcinoma(UTUC)and evaluate its performance.Methods:This retrospective cohort study analyzed the clinical data of 99 UTUC patients treated at the First Affiliated Hospital of Nanjing Medical University from April 2018 to May 2024. Among them,69(69.7%)were male and 30(30.3%)were female,with a median age of 67.0 years. All patients underwent preoperative MRI and radical nephroureterectomy. According to postoperative pathology,tumors staged ≥ T 2 were assigned to the muscle-invasive group,and those staged ≤ T 1 were assigned to the non-muscle-invasive group. Baseline data,pathological information,and imaging characteristics were collected and compared between the two groups. Logistic regression analysis was performed to identify risk factors for muscle-invasive UTUC,and a nomogram was constructed. The diagnostic performance of the model was assessed using receiver operating characteristic(ROC)curves,calibration curves,and decision curve analysis(DCA). Results:Among the 99 patients,70(70.7%)were diagnosed with muscle-invasive UTUC,and 29(29.3%)with non-muscle-invasive UTUC. The muscle-invasive group had significantly larger tumor size[4.5(2.8,7.0)cm vs. 3.0(2.3,4.5)cm, P = 0.029],a higher incidence of multifocal tumors[37.1%(26/70)vs. 3.5%(1/29), P < 0.001],patchy tumors[30.0%(21/70)vs. 6.9%(2/29), P = 0.019],spiculated tumor margins[52.9%(37/70)vs. 17.2%(5/29), P = 0.001],tumor compression on renal parenchyma or periureteral/peripelvic fat[68.6%(48/70)vs. 10.3%(3/29), P < 0.001],high-grade pathology[92.9%(65/70)vs. 75.9%(22/29), P = 0.043],lymph node metastasis[28.6%(20/70)vs. 0, P = 0.001],and lymphovascular invasion[42.9%(30/70)vs. 10.3%(3/29), P=0.002]. The apparent diffusion coefficient(ADC)values[0.9(0.8,1.1)× 10 -3 mm2/s vs. 1.1(1.0,1.4)× 10 -3 mm2/s, P < 0.001]and normalized ADC(NADC)values[0.8(0.7,1.0)vs. 0.9(0.8,1.1), P = 0.002]were significantly lower in the muscle-invasive group. Univariate logistic regression identified multifocality,patchy tumor patterns,spiculated tumor margins,tumor compression on renal parenchyma or periureteral/peripelvic fat,and low NADC values as risk factors for muscle-invasive UTUC(all P < 0.05). Multivariate analysis revealed multifocality( OR = 17.903,95% CI 1.650 - 194.253, P = 0.018),tumor compression on renal parenchyma or perirenal / ureteral fat( OR = 14.690,95% CI 3.069 - 70.323, P < 0.001),and low NADC value( OR = 0.016,95% CI 0.001 - 0.471, P = 0.017)as independent risk factors. A nomogram was constructed based on these factors. The area under the ROC curve(AUC)of the model was 0.898(95% CI 0.838 - 0.957),with an optimal cutoff value of 0.639. The model showed an accuracy of 83.8%,sensitivity of 81.4%,and specificity of 89.7%. Calibration curves indicated good calibration,and DCA showed that the model provided substantial clinical net benefit. Conclusions:This study constructed a nomogram based on preoperative MRI features,including tumor multifocality,compression on renal parenchyma or periureteral/peripelvic fat and NADC value,which demonstrates good predictive performances for muscle-invasive UTUC.
9.Bibliometric Analysis of Research Hotspots and Trends of Sijunzi Decoction
Jun YUAN ; Cheng ZHENG ; Yun LIU ; Jie XU ; Xiao DING ; Fuyan LI ; Zhimeng XU
Journal of Guangzhou University of Traditional Chinese Medicine 2025;42(9):2342-2348
Objective To conduct a bibliometric analysis of domestic and international literature on the research of Sijunzi Decoction over the past 20 years,and to explore the research status,hotspots,and development trends of Sijunzi Decoction.Methods This article retrieved journal articles related to the research of Sijunzi Decoction from 2004 to 2024 in the CNKI,Wanfang,VIP,and Web of Science databases.Microsoft Excel was used for publication volume analysis,while CiteSpace software was employed for keyword co-occurrence,clustering,and burst analysis,and then the analysis results were visualized.Results After literature retrieval and screening,3 573 Chinese articles and 113 English articles were included.Over the past two decades,the publication volume showed a trend of steadily increasing.The most frequent keywords in Chinese and English literature on the research of Sijunzi Decoction were spleen deficiency syndrome and gene expression,while the keywords with strongest burst were experimental research and data mining.Conclusion The research of Sijunzi Decoction in the last 20 years was mainly through animal experiments and clinical applications,and the research hotspots focus on the treatment of diseases of spleen deficiency syndrome and on the improvement of immune function of cancer patients.The extraction and identification of active components in Sijunzi Decoction and the study on the therapeutic mechanism in diseases of spleen deficiency syndrome are probably the future research trends.
10.Analysis of thickness changes in peripapillary retinal nerve fiber layer and associated risk factors in patients with Moyamoya disease
Shui-Qin CAO ; Xiao-Han HU ; Fang-Bing HAO ; Qing GUO ; Ran DING ; Hui LI ; Li-Li CHEN ; Li-Li ZHANG ; Ge LIANG
Medical Journal of Chinese People's Liberation Army 2025;50(7):855-861
Objective To investigate the characteristics of thickness changes in peripapillary retinal nerve fiber layer(pRNFL)and identify related risk factors in patients with Moyamoya disease(MMD).Methods A retrospective study was conducted on 150 MMD patients(150 eyes)aged 6-65 years admitted to the Neurosurgery Department of the Fifth Medical Center,Chinese PLA General Hospital from May 2016 to December 2023(observation group),and 150 age-matched healthy volunteers(150 eyes)from the hospital's ophthalmology outpatient department(control group).Both groups were subdivided into pediatric(≤18 years),young adult(18-40 years),and middle-aged(40-65 years)subgroups.The pRNFL thickness in four quadrants was measured by optical coherence tomography(OCT):superior(pRNFL-Sup),inferior(pRNFL-Inf),nasal(pRNFL-Nas),temporal(pRNFL-Tmp),and average thickness(pRNFL-Avg).General clinical data and pRNFL thickness were compared between two groups.Univariate and multivariate logistic regression analyses were performed to identify risk factors for pRNFL thinning in MMD patients.The cohort was randomly divided into training(n=210)and validation(n=90)sets at a 7:3 ratio.A predictive model for pRNFL thinning in MMD patients was constructed based on logistic regression results.Model performance was evaluated using the area under the receiver operating characteristic curve(AUC),and clinical utility was assessed via decision curve analysis.Results Compared with control group,MMD patients exhibited significantly reduced pRNFL-Avg,pRNFL-Sup,pRNFL-Tmp,and pRNFL-Inf thickness(P<0.05 or P<0.001),while pRNFL-Nas showed no significant difference(P>0.05).In the pediatric subgroup,pRNFL-Avg and pRNFL-Inf were thinner(P<0.05).In the young adult subgroup,pRNFL-Avg and pRNFL-Sup were reduced(P<0.001 or P<0.05).In the middle-aged subgroup,pRNFL-Avg,pRNFL-Sup,pRNFL-Inf,and pRNFL-Tmp were all thinner(P<0.05 or P<0.001).Multivariate logistic regression identified visual field defects(OR=15.28,95%CI 2.95-79.10),disease duration(OR=1.11,95%CI 1.05-1.18),and the number of involved cerebral vessels(OR=1.49,95%CI 1.01-2.22)as independent risk factors for pRNFL thinning.The predictive model achieved AUC of 0.94(95%CI 0.91-0.97)and 0.95(95%CI 0.91-0.99)in the training and validation sets,respectively.Decision curve analysis confirmed the model's favorable clinical net benefit.Conclusion Thinning of pRNFL was observed in Moyamoya disease patients with visual field defects,disease duration,and cerebral vascular involvement identified as independent risk factors for pRNFL atrophy.

Result Analysis
Print
Save
E-mail