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.

BACKGROUND:Currently,there are many modeling methods for pelvic organ prolapse animal models,and the commonly used methods are vaginal balloon dilatation,oophorectomy and the combination of the two.There is no study comparing the three modeling methods in detail.OBJECTIVE:To construct and validate a rat animal model of pelvic organ prolapse using three different methods and to identify the advantages and disadvantages of various models.METHODS:Seventy-two 8-week SPF-grade female Sprague-Dawley rats were selected and randomly divided into four groups,namely,vaginal balloon dilatation group,ovariectomy group,ovariectomy combined with vaginal balloon dilatation group(the combined group),and the sham-operated group(no ovariectomy and no vaginal dilatation).The vaginal wall tissues of rats were collected at 4,8 and 12 weeks after the operation for hematoxylin-eosin staining,Masson staining,EVG staining and immunohistochemical staining of α-smooth muscle actin,Vimentin and matrix metalloproteinase 9 detection,and the pelvic floor muscle tissues were taken at 4,8 and 12 weeks after the operation for hematoxylin-eosin staining,Masson staining and EVG staining.RESULTS AND CONCLUSION:(1)Hematoxylin-eosi staining showed that there was no significant difference in the decrease of vaginal epithelial layer thickness in the vaginal balloon dilatation group compared with the sham-operated group,(P＞0.05),while the thickness of the vaginal epithelial layer was significantly reduced in the ovariectomy group and the ovariectomy combined with vaginal balloon dilation group(P＜0.001),and the reduction was more significant in the ovariectomy combined with vaginal balloon dilation group,remained stable at 8 weeks after surgery and lasted until 12 weeks.(2)The changes in the content of collagen fibers and elastic fibers in the vaginal wall stained by Masson and EVG staining were the same as the changes in the thickness of the vaginal epithelial layer stained by hematoxylin-eosin,and there were no changes in collagen fibers and elastic fibers in the pelvic floor muscle tissues of the treatment groups.(3)At 4,8 and 12 weeks after treatment,there was no significant difference in the expression levels of α-smooth muscle actin,Vimentin and matrix metalloproteinase 9 in the vaginal wall tissue of the balloon dilation group compared with the control group(P＞0.05),whereas the expression levels of α-smooth muscle actin and Vimentin were significantly decreased in the ovariectomy group and ovariectomy combined with vaginal balloon dilation group(P＜0.01)and the expression of matrix metalloproteinase 9 showed a significant increase(P＜0.01),with a more pronounced increase in the ovariectomy combined with vaginal balloon dilation group,and the increase reached a stable state at 8 weeks after surgery and could persist up to 12 weeks.To conclude,vaginal balloon dilatation could not maintain the degeneration of pelvic organ prolapse formed by the vaginal wall for a long period,and both ovariectomy and the combined method can be used.Ovariectomy combined with vaginal balloon dilatation can significantly accelerate and aggravate the formation of typical histological features of pelvic organ prolapse in vaginal wall tissues,effectively shorten the experimental period,and improve the efficiency.These effects reach a stable state at 8 weeks after surgery and can be sustained up to 12 weeks,which is practical and convenient for the study of pelvic organ prolapse animal models.

BACKGROUND:Naringin has been shown to promote the proliferation and osteogenic differentiation of bone marrow derived mesenchymal stem cells,making it a potential candidate for treating osteoporosis andenhancing fracture healing.However,its clinical application is limited by its low bioavailability.OBJECTIVE:To prepare chitosan/β-tricalcium phosphate scaffolds loaded with naringin and characterize their biological properties.METHODS:Chitosan/β-tricalcium phosphate scaffolds were prepared by freeze-drying and chemical crosslinking.The chitosan/β-tricalcium phosphate scaffolds were immersed in anhydrous ethanol solution containing naringin for 3 hours.After vacuum cold drying,chitosan/β-tricalcium phosphate/naringin scaffolds were obtained.The pore size,porosity,swelling rate,degradation rate,mechanical properties,and in vitro release capacity of naringin of the scaffolds were characterized.Rat bone marrow mesenchymal stem cells were inoculated on the surface of chitosan/β-tricalcium phosphate scaffolds and chitosan/β-tricalcium phosphate/naringin scaffolds,respectively,and cell proliferation,adhesion,activity and alkaline phosphatase activity after osteogenic differentiation were detected.RESULTS AND CONCLUSION:(1)The results of scanning electron microscopy showed that the naringin-chitosan/β-tricalcium phosphate composite scaffold had a porous mesh structure.The average pore diameter was(106.82±25.22)μm;the porosity was(76.26±4.81)％;24-hour swelling rate was(796.17±31.76)％;in vitro degradation rate of 7.71％at 4 weeks,and naringin could be slowly released in vitro for 9 days.There was no significant difference in the average pore size,porosity,24-hour swelling rate,in vitro degradation rate,compression strength and compression modulus at 4 weeks between the chitosan/β-tricalcium phosphate scaffold and the chitosan/β-tricalcium phosphate scaffold(P＞0.05).(2)Rat bone marrow mesenchymal stem cells adhered well to the surfaces of the two scaffolds and had good activity.Compared with the chitosan/β-tricalcium phosphate scaffold,the chitosan/β-tricalcium phosphate/naringin scaffold promoted the proliferation of rat bone marrow mesenchymal stem cells(P＜0.05),and increased the alkaline phosphatase activity of bone marrow mesenchymal stem cells after osteogenic differentiation(P＜0.05).(3)The results show that the chitosan/β-tricalcium phosphate/naringin scaffolds exhibit favorable physical properties and can effectively promote the adhesion,proliferation,and osteogenic differentiation of bone marrow-derived mesenchymal stem cells.

BACKGROUND:Studies have found that probiotics have a certain preventive and therapeutic effect on peri-implantitis,and there are further explorations in the mechanism against peri-implantitis.OBJECTIVE:To review the mechanism and clinical application of probiotics in the treatment of peri-implantitis.METHODS:Relevant literature was searched on PubMed,Web of Science,CNKI,and WanFang Data,using the search terms of"probiotics,peri-implantitis,flora imbalance,immunoregulation,inflammatory reaction,mechanism of action"in Chinese and English.A total of 90 articles were finally included.RESULTS AND CONCLUSION:Probiotics have the following mechanisms.They can activate the anti-inflammatory mechanism by inhibiting the secretion of inflammatory factors and promoting the production of anti-inflammatory factors.They can destroy the cell wall of pathogenic bacteria by secreting microbial complexes and bacteriocins,reduce the pH value of biofilms,improve the composition of microorganisms in microecology,induce the change of bacterial community structure,and restore the balance of microbial population around implants.They have immunomodulatory effects and can enhance the resistance of the host oral mucosa to pathogenic bacteria in the surrounding area of the implant.In addition,probiotics can produce antibacterial compounds,offset the adhesion of pathogenic microorganisms,and regulate immune function.Through the above mechanisms,probiotics have certain potential in the adjuvant treatment of peri-implantitis,which can improve the clinical parameters of peri-implantitis and affect the microbiota.Probiotic therapy provides a new treatment option,but more long-term prospective studies are needed to further verify its effect.

BACKGROUND:Autologous bone,allogeneic bone or artificial bone has been used to promote bone defect repair in the clinic,but the rate of non-healing is still high.The key is to ignore the importance of periosteum in the bone healing process.In the early stage of the project,the project team constructed an electrospinning membrane loaded with vascular endothelial growth factor to highly simulate the intramembranous osteogenesis of natural periosteum at the bone defect site,which promoted bone regeneration to a certain extent.However,the injured area often faces the dilemma of severe inflammatory response mediated by macrophages and lack of seed cells,resulting in the risk of inactivation or diffusion of delivered biological factors.Therefore,it is necessary to further optimize and coordinate the immune regulation and angiogenesis functions of biomimetic periosteum to promote bone repair.OBJECTIVE:To investigate the physicochemical properties of stem cell-engineered bionic periosteum and its role in regulating the inflammatory microenvironment to promote bone repair.METHODS:By combining L-polylactic acid-based microsol electrospinning,type Ⅰ collagen self-assembly and gel stem cell transplantation technology,a bionic periosteum(M@C-B)was constructed,in which the core layer loaded with vascular endothelial growth factor and the shell layer delivered bone marrow mesenchymal stem cells to regulate the immune microenvironment of bone defects.The physicochemical properties of the periosteum were characterized by scanning electron microscopy,transmission electron microscopy,and Fourier transform infrared spectroscopy.A co-culture system was established between the bionic periosteum and macrophages,bone marrow mesenchymal stem cells and human umbilical vein endothelial cells to explore immune regulation and in vitro osteogenic and angiogenic abilities.Finally,the osteogenic properties of the stem cell engineered bionic periosteum were further verified in a rat femoral condyle defect model.RESULTS AND CONCLUSION:(1)Transmission electron microscopy results showed that the micro-sol electrospinning(MS)formed a distinct core-shell structure.Scanning electron microscopy indicated that after the assembly of the collagen-l artificial periosteum(M@C)on the surface of the vascular endothelial growth factor-loaded micro-sol,a distinct"spider web-like"fibrous structure was deposited.Infrared spectroscopy further confirmed the successful self-assembly of collagen-l.Release experiments demonstrated that the M@C group mitigated the burst release phenomenon compared to the MS group,maintaining internal vascular endothelial growth factor activity and sustained release.(2)Live/dead cell staining and CCK-8 assay showed that bone marrow mesenchymal stem cells proliferated well and survived on three types of artificial periosteum:MS,purely aligned poly(L-lactic acid)(PLLA)surface self-assembled collagen-l artificial periosteum(PLLA@C),and vascular endothelial growth factor-loaded micro-sol fiber surface self-assembled collagen-l-bone marrow mesenchymal stem cells artificial periosteum(M@C-B).Among them,the M@C-B group had the highest number of live cells and the fastest proliferation rate.(3)Alkaline phosphatase staining,alizarin red staining,and osteopontin immunofluorescence staining showed that the PLLA@C and M@C-B groups significantly promoted osteogenic differentiation of bone marrow mesenchymal stem cells.Angiogenesis experiments demonstrated that the vascular endothelial growth factor-loaded groups(MS and M@C-B)had longer blood vessel lengths and more reticular vascular-like structures with more cross-linked nodes,with the M@C-B group being the most prominent.(4)Immunofluorescence and flow cytometry showed that artificial periosteum in the M@C-B group significantly inhibited the pro-inflammatory macrophage phenotype and promoted the polarization of macrophages towards the anti-inflammatory M2 phenotype.(5)In vivo studies further confirmed that the M@C-B group showed superior bone mineral density,trabecular thickness,relative bone volume,and trabecular spacing compared to other groups.(6)These results indicate that bone marrow mesenchymal stem cell-engineered artificial periosteum,through the rapid regulation of the bone defect immune microenvironment by the collagen-l-bone marrow mesenchymal stem cells outer phase and the sustained release of vascular endothelial growth factor by the micro-sol electrospinning core-shell structure of the inner phase,synergistically promotes bone healing.

BACKGROUND:Studies have shown that lipid metabolism and related diseases can affect the development of osteoporosis.OBJECTIVE:Using bibliometric visualization analysis software to analyze and summarize the frontier content and research hotspots in the field of lipid metabolism affecting osteoporosis.METHODS:Using the Web of Science core collection database as the retrieval platform,relevant literature regarding the effect of lipid metabolism on osteoporosis from 2004 to 2024 was retrieved.VOSviewer and CiteSpace were used for bibliometric and visual analyses.RESULTS AND CONCLUSION:A total of 1 277 articles were included,and the number of articles on the effect of lipid metabolism on osteoporosis at home and abroad was increasing year by year.The number of articles published in China was 417,ranking first,and the United States was 243,ranking second.Shanghai Jiao Tong University ranked first with 30 articles.Professor Rosen Clifford J from Tufts University School of Medicine and Professor Recker Robert R from Clayton University were the most cited authors.The number of documents published in BONE in the Netherlands ranked first,and the JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM in England was the most cited journal.Bone mineral density,bone metabolism,menopause,and obesity were the core keywords,and they were also research hotspots in this field.The above results show that in the past 20 years,research in the field of lipid metabolism affecting osteoporosis has focused on the role of abnormal lipid metabolism in bone mineral density and bone metabolism,thereby regulating osteoporosis and post-menopause osteoporosis.Clarifying the pathway of this mechanism and"bone-lipid balance"is the future research idea and direction.

BACKGROUND:The quadriceps strength of patients with osteoporosis and sarcopenia is significantly reduced,which can further reduce the function of the knee joint,affect the function of the lower limbs and even lead to a decrease in whole-body coordination.It is speculated that a reasonable quadriceps training program and personalized guidance are beneficial to the recovery of knee joint function in patients with osteoporosis and sarcopenia.OBJECTIVE:To observe the effect of short-term moderate-intensity resistance rehabilitation training on the mass and function of the quadriceps and knee joint function in patients with osteoporosis and sarcopenia.METHODS:Using the integrated physical examination and rehabilitation model,375 patients with osteoporosis and sarcopenia were screened at the Health Management Center of Shanghai Public Health Clinical Center.They underwent 12 weeks of combined/comprehensive exercise rehabilitation based on resistance exercise,including quadriceps resistance isotonic and isometric contraction training twice a week(3-5 sets each time,10-15 minutes per set)and aerobic exercise/balance exercise two or three times a week(30 minutes each time).Assessments and data collection were performed before rehabilitation training,12 weeks after rehabilitation training,and at follow-up 12 weeks after stopping rehabilitation training,mainly including knee joint range of motion and proprioception,quadriceps muscle strength,and cross-sectional area(magnetic resonance imaging results),pain,knee joint function(Hospital for Special Surgery score)and walking function("up-and-go"time and 6 m pace test results)as well as the patient's psychological status assessment.RESULTS AND CONCLUSION:All 375 patients completed 12 weeks of rehabilitation training and 12 weeks of follow-up without any adverse events.(1)Compared with before training,the patients' gait speed and knee range of motion increased significantly after 12 weeks of rehabilitation training(P＜0.01),the time of"stand-to-walk"decreased(P＜0.01),and the proprioception of the knee joint and the strength of the quadriceps femoris were significantly improved(P＜0.01);and at the follow-up visit 12 weeks after stopping training,the above indicators and functions of the patients were well maintained(P＞0.05).(2)Magnetic resonance imaging results showed that the effective cross-sectional area of the quadriceps femoris did not improve significantly after 12 weeks of rehabilitation training(P＞0.05);but the Hospital for Special Surgery score of knee joint function increased significantly(P＜0.01),and the visual analog pain scale score decreased significantly(P＜0.01),suggesting that this may be related to the improvement of quadriceps femoris quality by resistance rehabilitation training.(3)The results of the Hospital Anxiety and Depression Scale score showed that the anxiety and depression scores of the patients continued to decrease,both at 12 weeks of rehabilitation training and at 12 weeks after stopping training(P＜0.01).It is suggested that resistance rehabilitation training of the quadriceps can help patients with osteoporosis and sarcopenia to restore quadriceps muscle strength,increase range of motion,improve proprioception and joint stability,thereby enhancing knee joint function,reducing pain,improving depression and anxiety,and to a certain extent promoting the coordinated recovery of the musculoskeletal system.

Objective:To investigate the survival outcomes and prognostic factors in patients undergoing radical resection for pancreatic body and tail cancer.Methods:A retrospective case series study was conducted on 992 patients who underwent radical resection for pancreatic body and tail cancer at the Pancreatic Center of the First Affiliated Hospital of Nanjing Medical University from January 2016 to June 2024. In this study, 577 (58.2%) were male and 415 (41.8%) were female,with an age of (65±9) years (range: 26 to 86 years). Follow-up continued until June 2024. Survival rates were estimated using the Kaplan-Meier method,and prognostic factors were identified using univariate and multivariate Cox proportional hazards models.Results:Among 992 patients,open surgery was the predominant approach (89.1%, 884/992), and radical antegrade modular pancreatosplenectomy (RAMPS) was performed in 317 patients (32.0%). Combined organ resection,venous resection,and arterial resection were performed in 23.5%, 9.3%,and 11.2% of patients,respectively. The rates of R0, R1-1 mm, and R1-direct resections were 49.8% (494/992),41.5% (412/992), and 8.7% (86/992),respectively. Stage ⅡB was the most common TNM stage (32.2%,319/992). A total of 801 patients (80.8%) received adjuvant chemotherapy. The median follow-up period was 32.0(8.8) months(range:3.2 to 105.3 months),during which 508 patients (51.2%) died. The overall median survival (OS) was 26.4 months,with 1-,3-, and 5-year survival rates of 79.0%,40.0%, and 29.0%, respectively. In the recent five years (from 2020 to 2024), the median OS improved significantly to 34.1 months compared to 20.0 months from 2016 to 2019 ( P<0.01). Histological subtype analysis showed that the median OS time was 26.7 months for pancreatic ductal adenocarcinoma (PDAC, n=855),58.9 months for invasive intraductal papillary mucinous carcinoma (IPMC, n=32),and 15.7 months for adenosquamous carcinoma of pancreas (ASCP, n=73) ( P=0.001). Among PDAC patients, adjuvant chemotherapy significantly improved survival (29.1 months vs. 14.4 months, P<0.01);in IPMC patients, adjuvant chemotherapy also extended survival (65.7 months vs. 58.9 months, P=0.047). Although ASCP patients receiving chemotherapy had a longer median OS time than those without (18.8 months vs. 8.9 months),the difference was not statistically significant ( P=0.151). Multivariate Cox regression analysis in PDAC patients indicated that adjuvant chemotherapy, R0 resection, T stage,N stage,and tumor differentiation were independent prognostic factors ( P<0.01). The median OS time by TNM stage was:not reached for stage ⅠA, 51.6 months for ⅠB, 25.5 months for ⅡA, 23.7 months for ⅡB, 23.0 months for Ⅲ, and 14.4 months for Ⅳ. The median OS time for R0,R1-1 mm,and R1-direct resections was 34.1,24.7,and 15.7 months,respectively ( P<0.01). Conclusion:Adjuvant chemotherapy,R0 resection,tumor stage,and differentiation are independent prognostic factors for pancreatic body and tail cancer.

Objective:To investigate the main causes of failed endoscopic retrograde cholangiopancreatography (ERCP) in children and the remedial treatment strategies.Methods:This retrospective cohort study analyzed the clinical data of 21 children who experienced failed ERCP at Beijing Children′s Hospital, Capital Medical University between January 2021 and December 2024. Data was collected included demographic information, clinical diagnoses, and ERCP outcomes. The annually trend in the ERCP failure rate was analyzed. Patients were categorized by etiology into the following groups: chronic pancreatitis, post-surgical status, pancreatic trauma, pancreas divisum, non-neoplastic pancreatic lesions, and ulcerative colitis. The relationship between etiologies and ERCP failure was analyzed by Fisher exact test.Results:A total of 175 ERCP procedures were included, of which 21 procedures failed (12.0%). The failure rate decreased annually from 2021 to 2024: 18.2% (4/22), 13.2% (5/38), 11.4% (5/44), and 9.9% (7/71), respectively. The etiological distribution among the 21 failed cases was as follows: chronic pancreatitis 28.6% (6/21), pancreatic duct stenosis following pancreatic trauma 23.8% (5/21), post-surgical status 14.3% (3/21), pancreas divisum 9.5% (2/21), acute pancreatitis 9.5% (2/21), non-neoplastic pancreatic lesions 9.5% (2/21), and pancreatic duct stenosis associated with ulcerative colitis 4.8% (1/21). Remedial treatments included surgical intervention (2 cases), ultrasound-guided percutaneous drainage (3 cases), and repeat ERCP (2 cases). For post-surgical and pancreatic trauma patients, failure was primarily due to bile duct stenosis, pancreatic duct stenosis, or pancreaticobiliary duct disruption. Active surgical interventions such as cholangiojejunostomy and pancreaticojejunostomy, and ultrasound-guided drainage following ERCP failure led to significant clinical improvement.Conclusions:A stratified management approach guided by etiology is essential following failed ERCP in children. Early and active remedial treatment, particularly surgical interventions, is recommended for post-surgical and pancreatic trauma cases.

OBJECTIVE To investigate the application status of prescription pre-review systems in healthcare institutions of Yunnan province， evaluate their system functions and management capabilities， and provide a practical basis for promoting rational drug use. METHODS A questionnaire survey was conducted among public healthcare institutions at or above the secondary level in Yunnan province to investigate the deployment status of the systems. A capability maturity assessment framework was constructed， encompassing 6 dimensions and 39 indicators， including real-time prescription review， prescription correlation review， rule setting， evidence-based information support， prescription authority management， and system operation management. This framework was then used to evaluate the institutions that had implemented the pre-review systems. RESULTS A total of 100 valid questionnaires were collected， with 37 institutions having adopted prescription pre-review systems， mainly tertiary hospitals. The system predominantly adopted a modular architecture and was embedded into the hospital information system through application programming interfaces and middleware， providing certain capabilities for real-time prescription risk identification. Evaluation results indicated that basic functions such as reviewing indications， contraindications， and drug compatibility performed well， while deficiencies remained in functions related to parenteral nutrition prescription， review of drug dosage for specific diseases， individual patient characteristic recognition， and rule setting. Moreover， the construction of review centers and establishment of management systems were also not well-developed. CONCLUSIONS The overall application rate of prescription pre-review systems in Yunnan province remains low. System functions and management mechanisms require further improvement. It is recommended to enhance information infrastructure in lower-level institutions and explore regionally unified review models to promote standardized and intelligent development of prescription review practices.