1.Restoration of osteogenic differentiation of bone marrow mesenchymal stem cells in mice inhibited by cyclophosphamide with psoralen
Chenglong WANG ; Zhilie YANG ; Junli CHANG ; Yongjian ZHAO ; Dongfeng ZHAO ; Weiwei DAI ; Hongjin WU ; Jie ZHANG ; Libo WANG ; Ying XIE ; Dezhi TANG ; Yongjun WANG ; Yanping YANG
Chinese Journal of Tissue Engineering Research 2025;29(1):16-23
BACKGROUND:Psoralen has a strong anti-osteoporotic activity and may have a restorative effect on chemotherapy-induced osteoporosis. OBJECTIVE:To explore the restorative effect of psoralen on the osteogenic differentiation of bone marrow mesenchymal stem cells in mice inhibited by cyclophosphamide and its mechanism. METHODS:C57BL/6 mouse bone marrow mesenchymal stem cells were isolated and cultured.Effect of psoralen on viability of bone marrow mesenchymal stem cells was detected by MTT assay.Osteogenic induction combined with alkaline phosphatase staining was used to determine the optimal dose of psoralen to restore the osteogenic differentiation of bone marrow mesenchymal stem cells inhibited by cyclophosphamide.The mRNA expression levels of Runx2,alkaline phosphatase,Osteocalcin,osteoprotegerin,and Wnt/β-catenin signaling pathway-related genes Wnt1,Wnt4,Wnt10b,β-catenin,and c-MYC were measured by RT-qPCR at different time points under the intervention with psoralen.The protein expression of osteogenic specific transcription factor Runx2 and Wnt/β-catenin signaling pathway related genes Active β-catenin,DKK1,c-MYC,and Cyclin D1 was determined by western blot assay at different time points under the intervention with psoralen. RESULTS AND CONCLUSION:(1)There was no significant effect of different concentrations of psoralen on the viability of bone marrow mesenchymal stem cells.The best recovery of the inhibition of osteogenic differentiation of bone marrow mesenchymal stem cells caused by cyclophosphamide was under the intervention of psoralen at a concentration of 200 μmol/L.(2)Psoralen reversed the reduction in osteogenic differentiation marker genes Runx2,alkaline phosphatase,Osteocalcin and osteoprotegerin mRNA expression and Runx2 protein expression in bone marrow mesenchymal stem cells caused by cyclophosphamide conditioned medium.(3)Psoralen reversed the decrease in Wnt/β-catenin pathway-related genes Wnt4,β-catenin,c-MYC mRNA and Active β-catenin,c-MYC,and Cyclin D1 protein expression and the increase in DKK1 protein expression in bone marrow mesenchymal stem cells caused by cyclophosphamide conditioned medium.(4)The results showed that cyclophosphamide inhibited osteogenic differentiation of bone marrow mesenchymal stem cells in mice,and psoralen had a restorative effect on it.The best intervention effect was achieved at a concentration of 200 μmol/L psoralen,and this protective effect might be related to the activation of Wnt4/β-catenin signaling pathway by psoralen.
2.Relationship Between YWHAQ Expression and Clinicopathological Features and Prognosis of Patients with Gastric Adenocarcinoma
Xueqing LIU ; Libo YANG ; Linhai LI ; Ping SHENG ; Sicheng LIU ; Lihua LI
Cancer Research on Prevention and Treatment 2025;52(5):393-399
Objective To investigate the expression of YWHAQ protein in gastric adenocarcinoma tissues and its correlation with clinical pathological features and prognosis. Methods A total of 127 patients with gastric cancer who underwent radical surgery were enrolled. Clinical data and postoperative cancer tissue samples were collected from the patients. Immunohistochemistry was used to detect the protein expression of YWHAQ in gastric adenocarcinoma tissues. The relationship between YWHAQ expression and clinical pathological features and prognosis was analyzed. Bioinformatics prediction was performed to identify potential pathways regulated by YWHAQ in gastric adenocarcinoma. A protein-protein interaction network for YWHAQ was constructed using the STRING database. Results YWHAQ gene expression was significantly higher in gastric adenocarcinoma tissues than in normal tissues (P<0.05). The expression level of the YWHAQ protein was significantly correlated with age, tumor invasion depth, lymph node metastasis, and tumor stage (P<0.05). Kaplan-Meier survival analysis showed that patients with high YWHAQ expression had significantly poorer long-term survival than those with low expression (P<
3.Analysis of sleep quality and influencing factors in migraine patients with patent foramen ovale
Yijun HU ; Diwen ZHANG ; Libo WANG ; Bo LIU ; Hongmei YE ; Xiongfei ZHAO
Sichuan Mental Health 2025;38(3):241-246
BackgroundMigraine is a common chronic neurological disease, and patent foramen ovale (PFO) has been closely associated with migraine. Current research primarily focuses on the pathological mechanism and the therapeutic effects of interventional closure, with limited attention paid to the impact of PFO on sleep quality in migraine patients. ObjectiveTo compare the difference in sleep quality between PFO-positive and PFO-negative migraine patients, and to analyzes influencing factors of sleep quality in PFO-positive migraine patients, so as to provide references for clinical interventions to improve sleep quality in PFO-positive migraine patients. MethodsA total of 673 migraine patients who met the diagnostic criteria of migraine in the International Classification of Headache Disorders, third edition (ICHD-3), and all patients underwent contrast-enhanced transcranial Doppler (c-TCD) and transthoracic echocardiographic right heart contrast echocardiography (cTTE) in the Third Hospital of Mianyang from January 2020 to October 2024. Basic demographic data were collected using a self-designed questionnaire, headache severity was assessed with the Visual Analogue Scale (VAS), and sleep quality was invaluated using the Pittsburgh Sleep Quality Index (PSQI). PFO patients was diagnosed through c-TCD combined with c-TTE. Binary logistic regression analysis was employed to examine the influencing factors of sleep quality in PFO-positive migraine patients. ResultsA total of 673 (100.00%) migraine patients were enrolled, including 223 PFO-positive cases (33.14%) and 450 PFO-negative cases(66.86%). The PFO-positive group showed significantly more severe headache severity (χ2=15.799, P<0.01) and poorer sleep quality (χ2=14.377, P<0.01) compared with PFO-negative group. PFO-positive patients demonstrated significantly higher barrier factor scores of sleep quality, sleep latency, sleep efficiency, sleep disturbance, hypnotic medication use, and daytime dysfunction compared with PFO-negative counterparts (t=3.634, 3.269, 2.785, 3.428, 2.907, 3.637, Bonferroni adjust P<0.05/7=0.007).By contrast, no significant difference was noted in sleep duration scores between the two groups(t=2.349, Bonferroni adjust P>0.05/7=0.007).The Binary Logistic regression analysis revealed that age (OR=1.021, 95% CI: 1.001~1.041), headache severity (OR=6.030, 95% CI: 4.085~8.901), and PFO grade (OR=1.893,95% CI: 1.288~2.784)were significant influencing factors for sleep quality in migraine patients with PFO. ConclusionMigraine patients with PFO-positive exhibited poorer sleep quality compared wtih PFO-negative patients. Older age, higher headache servity, and more severe PFO grade are identified as risk factors for impaired sleep quality in PFO-positive migraine patients.
4.Clinical application of locally trained and re-optimized lung SBRT RapidPlan model
Libo ZHANG ; Weiqiang GE ; Ye YAO
Chinese Journal of Radiological Health 2025;34(5):726-732
Objective To explore the clinical effectiveness of a locally trained and re-optimized RapidPlan model in lung stereotactic body radiation therapy (SBRT). Methods A total of 132 lung SBRT cases were retrospectively collected as a training group for the establishment of an initial RapidPlan model (RP-1) in the Eclipse 15.5 treatment planning system. RP-1 was then used to optimize the training group plans to generate the first-generation RapidPlans, which were used as a new training group to generate the upgraded RapidPlan model (RP-Plus). Additional 40 lung SBRT cases were selected to verify the quality and efficiency of RP-Plus plans, which were further assessed through clinical quality assurance (QA). Results The RP-Plus reduced the average number of optimization cycles by 2.1 times and 0.3 times compared to manual and RP-1 methods, respectively, and reduced the optimization time by 57.6% and 18.8%. The conformity index met clinical requirements, and the gradient index and Max2cm(%) were improved compared to RP-1 (both P < 0.05). The RP-Plus plans showed lower dosimetric parameters of organs at risk, including lung V20Gy, spinal cord Dmax, and heart
5.Correlation between urination intermittences and urodynamic parameters in benign prostatic hyperplasia patients.
Ning LIU ; Libo MAN ; Feng HE ; Guanglin HUANG ; Jianpo ZHAI
Journal of Peking University(Health Sciences) 2025;57(2):328-333
OBJECTIVE:
To explore the impact factors and the clinical significance of the urination intermittences in benign prostatic hyperplasia (BPH) patients.
METHODS:
A retrospective study was performed in BPH patients who underwent urodynamic studies in Beijing Jishuitan Hospital form January 2016 to June 2021. The patients were aged 45 to 84 years with a median age of 63 years, and all the patients had no previous history of neurological disease and had no positive findings in neurological examinations. All the patients had free uroflometry followed by urethral catheterization and urodynamic tests. The voiding work of bladder was calculated using the detrusor power curve method, and the voiding power of bladder and the voiding energy consumption were also calculated. The frequency of urination intermittences generated in uroflometry was also recorded and the patients were divided into different groups according to it. The detrusor pressure at maximal flow rate (PdetQmax), the maximal flow rate (Qmax), the bladder contractile index (BCI), the bladder outlet obstruction index (BOOI), the voiding work, the voiding power, and the voiding energy consumption were compared among the different groups. Multiva-riate analyses associated with presence of urination intermittences were performed using step-wise Logistic regressions.
RESULTS:
There were 272 patients included in this study, of whom, 179 had no urination intermittence (group A), 46 had urination intermittence for only one time (group B), 22 had urination intermittence for two times (group C), and 25 had urination intermittence for three times and more (group D). The BCI were 113.4±28.2, 101.0±30.2, 83.3±30.2, 81.0±30.5 in groups A, B, C, and D, respectively; The voiding power were (29.2±14.8) mW, (16.4±9.6) mW, (14.5±7.1) mW, (8.5±5.0) mW in groups A, B, C, and D, respectively, and the differences were significant (P < 0.05). The BOOI were 41.6±29.3, 46.4±31.0, 41.4±29.0, 42.7±22.8 in groups A, B, C, and D, respectively; The voiding energy consumption were (5.41±2.21) J/L, (4.83±2.31) J/L, (5.02±2.54) J/L, (4.39±2.03) J/L in groups A, B, C, and D, respectively, and the differences were insignificant (P>0.05). Among the patients, 179 cases were negative in presence of urination intermittences and 93 cases were positive. Step-wise Logistic regression analysis showed that bladder power (OR=0.814, 95%CI: 0.765-0.866, P < 0.001), BCI (OR=1.023, 95%CI: 1.008-1.038, P=0.003), and bladder work (OR=2.232, 95%CI: 1.191-4.184, P=0.012) were independent risk factors for urination intermittences in the BPH patients.
CONCLUSION
The presence of urination intermittences in the BPH patients was mainly influenced by bladder contractile functions, and was irrelevant to the degree of bladder outlet obstruction. The increase of frequency of urination intermittences seemed to be a sign of the decrease of the bladder contractile functions in the BPH patients.
Prostatic Hyperplasia/physiopathology*
;
Humans
;
Male
;
Urodynamics
;
Urination
;
Retrospective Studies
;
Middle Aged
;
Aged
;
Aged, 80 and over
;
Urinary Bladder/physiopathology*
;
Urination Disorders/etiology*
6.Differential Resting-State Brain Activity Following Early- and Late-Night Sleep Loss.
Tianqi DI ; Libo ZHANG ; Shiqiu MENG ; Yang GUO ; Wangyue LIU ; Enyu ZHENG ; Zhoulong YU ; Yan SUN ; Jie SHI
Neuroscience Bulletin 2025;41(9):1696-1700
7.Effective implementation of hour-1 bundle for sepsis patients in emergency department based on crisis resource management.
Chengli WU ; Jiaqiong SU ; Libo ZHAO ; Qin XIA ; Lan XIA ; Wanyu MA ; Ruixia WANG
Chinese Critical Care Medicine 2025;37(1):23-28
OBJECTIVE:
To explore the implementation effect of hour-1 bundle for sepsis patients based on crisis resource management (CRM) system.
METHODS:
A historical control study was conducted. The hour-1 bundle for sepsis based on CRM was used to train 24 nurses in the emergency department from October 2022 to March 2023. Clinical data of sepsis patients admitted to the emergency department of the First People's Hospital of Zunyi from April 2022 to September 2023 were collected. The patients were divided into three groups based on different stages of CRM system construction: control group (before construction, from April to September in 2022), improvement group (during construction, from October 2022 to March 2023) and observation group (after construction, from April to September in 2023). The baseline data, implementation rate of hour-1 bundle [including blood culture, antibiotic usage, blood lactic acid (Lac) detection, fluid resuscitation, hypertensors usage], identification and diagnosis time, and prognosis parameters [including correction rate of hypoxemia, intensive care unit (ICU) occupancy rate, and 28-day survival rate]. Sepsis cognition survey and non-technical skill (NTS) evaluation of nurses in emergency department were conducted before and after training.
RESULTS:
Finally 43 cases were enrolled in the control group, improvement group and observation group, respectively. There was no statistically significant difference in baseline data including the gender, age, primary site, heart rate, systolic blood pressure, acute physiology and chronic health evaluation II (APACHE II) score, sequential organ failure assessment (SOFA) score, mechanical ventilation ratio among the three groups with comparability. With the gradual improvement of the CRM system, the implementation rate of 1-hour bundle was gradually increased, and the implementation rate in the control group, improvement group and observation group were 65.12% (28/43), 74.42% (32/43) and 88.37% (38/43), respectively, with statistically significant difference (P < 0.05). It was mainly reflected in the completion rate of blood culture, antibiotic usage rate, Lac detection rate and hypertensors usage rate within 1 hour, which were significantly higher in the observation group than those in the control group [completion rate of blood culture: 90.70% (39/43) vs. 62.79% (27/43), antibiotic usage rate: 88.37% (38/43) vs. 60.47% (26/43), Lac detection rate: 93.02% (40/43) vs. 72.09% (31/43), hypertensors usage rate: 88.37% (38/43) vs. 60.47% (26/43), all P < 0.05]. The fluid resuscitation rates within 1 hour in the three groups were all over 90%, with no statistically significant difference among the three groups. The recognition and diagnosis time in the observation group was significantly shorter than that in the control group and the improvement group (hours: 0.41±0.15 vs. 0.61±0.21, 0.51±0.18, both P < 0.05), the correction rate of hypoxemia and 28-day survival rate were significantly higher than those in the control group [correction rate of hypoxemia: 95.35% (41/43) vs. 74.42% (32/43), 28-day survival rate: 83.72% (36/43) vs. 60.47% (26/43), both P < 0.05], and ICU occupancy rate was significantly lower than that in the control group [72.09% (31/43) vs. 93.02% (40/43), P < 0.05]. After training in the CRM system, the score of the sepsis awareness survey questionnaire for emergency department nurses was significantly increased as compared with before training (60.42±5.29 vs. 44.17±9.21, P < 0.01), and NTS also showed significant improvement.
CONCLUSION
CRM plays a significant role in promoting the implementation of sepsis hour-1 bundle, which can improve the implementation rate of hour-1 bundle and NTS of medical staff, effectively improve patients' hypoxemia, reduce patients' ICU occupancy rate and 28-day risk of death.
Humans
;
Sepsis/therapy*
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Emergency Service, Hospital
;
Patient Care Bundles
;
Intensive Care Units
;
Female
;
Male
;
Middle Aged
8.Effect of calcitonin gene-related peptide on autophagy in hypoxic/reoxygenated cardiomyocytes through regulation of PI3K/Akt/mTOR signaling pathway.
Chinese Critical Care Medicine 2025;37(1):53-58
OBJECTIVE:
To investigate the effects of calcitonin gene-related peptide (CGRP) on autophagy in hypoxic/reoxygenated (H/R) cardiomyocytes and its relationship with the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway.
METHODS:
The rat cardiomyocyte cell line H9c2 was routinely cultured in vitro and passaged for experiments when the cells grew to 80% fusion. (1) CGRP dosage screening experiment: the cells were divided into blank control group, H/R group and different dosages of CGRP pretreatment groups. H9c2 cells were placed in a closed hypoxia chamber for 2 hours and then reoxygenated in a conventional incubator for 12 hours to prepare the H/R model. The CGRP pretreatment groups were pretreated with 0.01, 0.1, 0.5, 1, 5, and 10 μmol/L CGRP before the modeling process. The blank control group was not given any treatment. Cell counting kit-8 (CCK-8) was used to detect the cell survival rate, and the most suitable drug dosage was screened out. (2) Intervention experiment: H9c2 cells were divided into blank control group, H/R group, CGRP+H/R group, and CGRP+PI3K target inhibitor ly294002 (LY)+H/R group. H/R group was prepared as cellular H/R model. CGRP (1 μmol/L) alone or in combination with LY (10 μmol/L) was administered to CGRP+H/R group and CGRP+LY+H/R group, respectively, prior to the preparation of cellular H/R model. The blank control group was cultured routinely without treatment. The cell survival rate was detected by CCK-8. The level of lactate dehydrogenase (LDH) release was detected by colorimetric assay. The expressions of autophagy-related proteins [autophagy effector protein Beclin-1, microtubule-associated protein 1 light chain 3-II (LC3-II), autophagy protein p62] and PI3K/Akt/mTOR signaling pathway proteins [phosphorylated Akt (p-Akt), phosphorylated mTOR (p-mTOR)] were detected by Western blotting.
RESULTS:
(1) Results of CGRP dosage screening experiment: compared with the blank control group, the cell survival rate of the H/R group decreased significantly; and after giving 0.1, 0.5, 1, 5 μmol/L CGRP for pretreatment, the cell survival rate increased significantly, and intervention effect of 1 μmol/L CGRP was the best, and the difference was statistically significant when compared with that of the H/R group [(74.23±6.18)% vs. (23.43±4.09)%, P < 0.01], so it was used as the intervention dosage for the subsequent experiment. (2) Intervention experiment results: compared with the blank control group, the cell survival rate in the H/R group was significantly reduced, the level of LDH release was significantly increased, the protein expressions of Beclin-1 and LC3-II were significantly increased, and the protein expressions of p62, p-Akt and p-mTOR were significantly reduced, indicating that the death of cardiomyocytes occurred after the treatment of H/R and was accompanied by the elevation of autophagy level, and this process was associated with the activation of PI3K/Akt/mTOR signaling pathway. Compared with the H/R group, CGRP pretreatment increased cell survival rate [(76.02±2.43)% vs. (46.15±3.29)%, P < 0.01], decreased the level of LDH release (U/L: 169.83±11.65 vs. 590.17±34.50, P < 0.01), and down-regulated the protein expressions of Beclin-1 and LC3-II [Beclin-1 protein (Beclin-1/β-actin): 1.27±0.15 vs. 1.93±0.19, LC3-II protein (LC3-II/LC3-I): 1.27±0.13 vs. 1.98±0.18, both P < 0.01], up-regulated the protein expressions of p62, p-Akt, p-mTOR [p62 protein (p62/β-actin): 0.96±0.02 vs. 0.63±0.05, p-Akt protein (p-Akt/Akt): 0.76±0.04 vs. 0.48±0.02, p-mTOR protein (p-mTOR/mTOR): 1.13±0.09 vs. 0.68±0.15, all P < 0.05], suggesting that CGRP was able to reduce the H/R-induced cardiomyocyte injury, and this process was accompanied by a decrease in the level of cellular autophagy and activation of the PI3K/Akt/mTOR signaling pathway. Compared with the CGRP+H/R group, the cell survival rate was significantly lower than that in the CGRP+LY+H/R group [(56.95±6.63)% vs. (76.02±2.43)%, P < 0.01], LDH release level was significantly higher (U/L: 436.00±27.44 vs. 169.83±11.65, P < 0.01), and the protein expressions of Beclin-1 and LC3-II were significantly up-regulated [Beclin-1 protein (Beclin-1/β-actin): 1.63±0.12 vs. 1.27±0.15, LC3-II protein (LC3-II/LC3-I): 1.61±0.13 vs. 1.27±0.13, both P < 0.01], and significantly down-regulated p62, p-Akt, and p-mTOR protein expressions [p62 protein (p62/β-actin): 0.57±0.09 vs. 0.96±0.02, p-Akt protein (p-Akt/Akt): 0.45±0.01 vs. 0.76±0.04, p-mTOR protein (p-mTOR/mTOR): 0.66±0.06 vs. 1.13±0.09, all P < 0.05], suggesting that PI3K-targeted inhibitor was able to reverse the protective effect of CGRP on H/R cells.
CONCLUSIONS
CGRP pretreatment attenuated H/R-induced cardiomyocyte injury, increased cell survival rate, and reduced cellular LDH release. This effect may be achieved through inhibiting the activation of PI3K/Akt/mTOR signaling pathway.
Animals
;
Myocytes, Cardiac/drug effects*
;
Signal Transduction/drug effects*
;
Rats
;
TOR Serine-Threonine Kinases/metabolism*
;
Calcitonin Gene-Related Peptide/pharmacology*
;
Proto-Oncogene Proteins c-akt/metabolism*
;
Autophagy/drug effects*
;
Cell Line
;
Cell Hypoxia
;
Phosphatidylinositol 3-Kinases/metabolism*
9.Juvenile Parkinson's disease caused by PRKN gene compound heterozygous mutation:A case report and literature review
Qian LI ; Chunyang KANG ; Xiaoyang LIU ; Libo WANG ; Jiajun CHEN ; Jia LI
Journal of Jilin University(Medicine Edition) 2024;50(1):248-253
Objective:To conduct the genetic analysis of a family with one patient suffering from juvenile Parkinson's disease(JP)and discuss the clinical manifestations,genetic mutation characteristics,and treatment plans prompted by PRKN gene compound heterozygous mutations,and to enhance the clinicians'awareness of this disease.Methods:The clinical data of one patient with JP caused by PRKN gene mutations was analyzed,the clinical manifestations and genetic mutation features of the patient were summarized,and the related literatures were reviewed.Results:The patient,a 16-year-old male,was admitted to the hospital due to unstable gait,trembling limbs with rigidity in both lower limbs for three years.The examination results revealed a panic gait,clear consciousness,fluent speech,normal muscle strength in limbs,increased"gear-like"muscle tone in both upper limbs,and"lead-pipe"rigidity in both lower limbs;the sensory functions and tendon reflexes were normal.The head,neck,and thoracic magnetic resonance imaging(MRI)results showed no abnormalities.18F-fluorodeoxyglucose(18F-FDG)positron emission tomography/computed tomography(PET/CT)results showed that the head size and shape were normal,the glucose metabolism in the left cerebellum and middle temporal gyrus was slightly decreased,and the glucose metabolism in bilateral thalami,right frontal lobe,parietotemporal lobe,and left medial frontal lobe was increased.The dopamine transporter(DAT)PET/CT results showed that there was no radioactive distribution in the brain cortex and the DAT distribution in the posterior part of both striata was decreased.The whole-exome sequencing results showed the patient had two PRKN gene mutations,such as codons c.8T>A and c.850G>C compound heterozygous mutations,and each mutation was from one parent;the patient's father carried the c.8T>A mutation,the patient's mother carried the c.850G>C mutation,and the patient's sister had the same genetic mutation site as the patient's father.Conclusion:PRKN gene compound heterozygous mutations may be the basis of the disease in this family.Identification of the mutation c.8T>A expands the mutation spectrum of the PRKN gene,and provides the valuable information for the research on the pathogenic genetic mutations of the JP patients.
10.Comparison of initial stability of mandibular first molar repaired with different threaded implants under immediate loading
Xinru LI ; Wenbo ZHAO ; Yan JI ; Weiwei TENG ; Yiming WANG ; Libo ZHOU
Chinese Journal of Tissue Engineering Research 2024;28(22):3445-3450
BACKGROUND:The threaded conical implant has a good ability to control micro movements and is conducive to immediate loading.However,the effects of double-threaded conical cylindrical implants and conical cylindrical implants on stress distribution and initial stability of implant-bone interface after immediate loading have not been reported. OBJECTIVE:To investigate the impact of double-threaded conical cylindrical implants and conical cylindrical implants on the biological distribution of the implant and the surrounding bone interface during immediate loading in the mandibular molar region. METHODS:(1)Three-dimensional finite element analysis:Conical beam CT scans of the mandible and first molar of a volunteer were used to develop a basal model of the mandible.The double-threaded conical cylindrical implants and conical cylindrical implants were assembled with the mandibular models,and an immediate-load(or delayed implantation)implant model(a total of four models)for the first mandibular molar was established.Loads in four directions(100 N):axial,lingual and buccal 45°,mesial and distal,and buccal and lingual,were applied to the central fossa of each model's crown.Three-dimensional finite element method was used to analyze the implant displacement and the stress distribution at the implant-bone interface.(2)In vitro experiment:With the assistance of the oral implant robot,the double-threaded conical cylindrical implants and conical cylindrical implants were implanted on the same artificial bone pieces,separately,and the immediate load model of immediate implant implantation(or delayed implantation)was established in vitro(a total of four groups of models).Osstell resonance frequency analyzer and SmartPeg sensor were used to measure the implant stability coefficient in four vertical directions:front,rear,left,and right measurements,evaluate the initial stability,and verify the finite element analysis results. RESULTS AND CONCLUSION:(1)The displacement difference between double-threaded conical cylindrical implants and conical cylindrical implants was small when the immediate loading of delayed implantation was applied,but the maximum stress value of conical cylindrical implant-bone interface was greater than that of double-threaded conical cylindrical implant-bone interface.When the immediate loading of immediate implantation was applied,the maximum stress value and the maximum displacement of bone around the implant appeared when the load was applied in mesiodistal direction.The stress value of the conical cylindrical implant reached 298.84 MPa and the maximum displacement was 0.31 mm,both of which were larger than that of the double-threaded conical cylindrical implant.(2)The results of in vitro experiments showed that the stability coefficient of the double-threaded conical cylindrical implant was greater than that of the conical cylindrical implant.(3)Compared with the conical cylindrical implant,the double-threaded conical cylindrical implant has higher initial stability under immediate loading,suggesting that the use of double-threaded conical cylindrical implant should be given priority in clinical immediate loading.

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