2.Analysis of Positive Results of Anti-M Unexpected Antibody in Pediatric Inpatients in Central China.
Dong-Dong TIAN ; Ding ZHAO ; Wei LI ; Yong-Jun WANG ; Hong-Bing HU ; Yuan-Qing YANG ; Zheng-Feng LI
Journal of Experimental Hematology 2025;33(4):1155-1160
OBJECTIVE:
To analyze the positive rate and distribution of anti-M unexpected antibody in pediatric inpatients aged 0 to 14 years in central China.
METHODS:
A total of 30 049 pediatric inpatients admitted to the Second Xiangya Hospital of Central South University, Wuhan Children's Hospital and Children's Hospital Affiliated of Zhengzhou University from May 2020 to August 2022 were enrolled in this study, and relevant clinical data were collected. Blood samples from the patients were tested for blood typing and screened for unexpected antibodies. For samples that screened positive for unexpected antibodies, identification was conducted using the identification panel to determine the specificity of the antibodies. The distribution and differences of anti-M antibodies in pediatric patients of different sexes, ages, blood groups, disease types, with or without a history of blood transfusion, and across different regions were analyzed.
RESULTS:
Among 30 049 inpatients, the positive rate of unexpected antibodies was 0.91% (273/30 049), of which the positive rate of anti-M antibodies was 0.44% (131/30 049). The positive rate of anti-M antibodies in the neonates aged 0 to < 1 month was 0.10% (5/4 881), and all of them were IgG antibodies from their mothers; The positive rate of anti-M antibodies for the group aged from 1 month to < 1 year old was 0.23% (7/3 108), with no anti-M antibodies detected in patients aged 1-6 months; The positive rates of anti-M antibodies in the 1-4 years old group, 5-9 years old group, and 10-14 years old group were 0.87% (88/10 064), 0.38% (27/7 190), and 0.08% (4/4 806), respectively. The positive rate of anti-M antibodies in the 1-4 years old group was significantly higher than that of the other groups ( P <0.001), and there were also statistical differences in the positive rate between the 5-9 years old group and the 0-< 1 month and 10-14 years old groups ( P <0.001). The prevalences of anti-M antibodies in ABO blood group A, B, O and AB were 0.32% (30/9 482), 0.70% (58/8 293), 0.32% (31/9 595) and 0.45% (12/2 679), respectively. The prevalence of anti-M antibodies in patients with blood group B was significantly higher than that in patients with blood groups A and O ( P <0.05). The prevalences of anti-M antibodies in Hunan, Hubei and Henan was 0.18%, 0.32% and 0.71%, respectively. The prevalence of anti-M antibodies in Henan was significantly higher than that in Hunan and Hubei ( P <0.05), and the distribution showed obvious regional differences between the north and the south. There were no significant differences in the positive rate of anti-M antibodies between the children with different sexes, disease types, and with or without a history of blood transfusion (P >0.05).
CONCLUSION
This study reveals the distribution pattern of anti-M antibodies in pediatric inpatients aged 0-14 years in central China, which has reference value for the research on unexpected red blood cell antibodies in Chinese children.
Humans
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Child
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China
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Infant
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Child, Preschool
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Adolescent
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Female
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Male
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Inpatients
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Infant, Newborn
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Blood Grouping and Crossmatching
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Antibodies/blood*
3.Efficacy and safety of recombinant human anti-SARS-CoV-2 monoclonal antibody injection(F61 injection)in the treatment of patients with COVID-19 combined with renal damage:a randomized controlled exploratory clinical study
Ding-Hua CHEN ; Chao-Fan LI ; Yue NIU ; Li ZHANG ; Yong WANG ; Zhe FENG ; Han-Yu ZHU ; Jian-Hui ZHOU ; Zhe-Yi DONG ; Shu-Wei DUAN ; Hong WANG ; Meng-Jie HUANG ; Yuan-Da WANG ; Shuo-Yuan CONG ; Sai PAN ; Jing ZHOU ; Xue-Feng SUN ; Guang-Yan CAI ; Ping LI ; Xiang-Mei CHEN
Chinese Journal of Infection Control 2024;23(3):257-264
Objective To explore the efficacy and safety of recombinant human anti-severe acute respiratory syn-drome coronavirus 2(anti-SARS-CoV-2)monoclonal antibody injection(F61 injection)in the treatment of patients with coronavirus disease 2019(COVID-19)combined with renal damage.Methods Patients with COVID-19 and renal damage who visited the PLA General Hospital from January to February 2023 were selected.Subjects were randomly divided into two groups.Control group was treated with conventional anti-COVID-19 therapy,while trial group was treated with conventional anti-COVID-19 therapy combined with F61 injection.A 15-day follow-up was conducted after drug administration.Clinical symptoms,laboratory tests,electrocardiogram,and chest CT of pa-tients were performed to analyze the efficacy and safety of F61 injection.Results Twelve subjects(7 in trial group and 5 in control group)were included in study.Neither group had any clinical progression or death cases.The ave-rage time for negative conversion of nucleic acid of SARS-CoV-2 in control group and trial group were 3.2 days and 1.57 days(P=0.046),respectively.The scores of COVID-19 related target symptom in the trial group on the 3rd and 5th day after medication were both lower than those of the control group(both P<0.05).According to the clinical staging and World Health Organization 10-point graded disease progression scale,both groups of subjects improved but didn't show statistical differences(P>0.05).For safety,trial group didn't present any infusion-re-lated adverse event.Subjects in both groups demonstrated varying degrees of elevated blood glucose,elevated urine glucose,elevated urobilinogen,positive urine casts,and cardiac arrhythmia,but the differences were not statistica-lly significant(all P>0.05).Conclusion F61 injection has initially demonstrated safety and clinical benefit in trea-ting patients with COVID-19 combined with renal damage.As the domestically produced drug,it has good clinical accessibility and may provide more options for clinical practice.
4.HIV detection in Jiading District from 2009 to 2023
ZHANG Yong ; DING Yingying ; ZHONG Peisong ; WANG Weibing ; FENG Yan ; WU Xuefu ; YIN Fanglan
Journal of Preventive Medicine 2024;36(12):1056-1059
Objective:
To analyze the HIV detection results through different detection routes in Jiading District, Shanghai Municipality from 2009 to 2023, so as to provide the reference for improving HIV detection measures.
Methods:
Data pertaining to HIV detection in Jiading District from 2009 to 2023 was collected through the HIV/AIDS Comprehensive Control System of Chinese Disease Prevention and Control Information System. The number of HIV detection and HIV positive rates through detection routes including voluntary counseling and testing (VCT) clinics, sexually transmitted disease (STD) clinics, pre-operation and blood transfusion (products), premarital and antenatal periods, other clinical outpatients and other populations were described.
Results:
A total of 1 729 347 HIV tests were conducted in Jiading District from 2009 to 2023, with an average annual growth rate of 7.55%. A total of 1 125 HIV positive cases were confirmed, with an HIV positive rate of 6.51/104. The number of HIV detection conducted in VCT clinics, STD clinics, pre-operation and blood transfusion (products), premarital and antenatal periods, other clinical outpatients and other populations were 11 516, 112 880, 692 609, 635 770, 196 315 and 80 257, respectively. The main detection routes were pre-operation and blood transfusion (products) as well as premarital and antenatal periods, accounting for 40.05% and 36.76%, respectively. The HIV positive rates in VCT clinics, STD clinics, pre-operation and blood transfusion (products), premarital and antenatal periods, other clinical outpatients and other populations were 336.05/104, 21.79/104, 2.93/104, 0.35/104, 10.95/104 and 6.48/104, respectively. The HIV positive rate in VCT clinics was higher than that in other detection routes (all P<0.001).
Conclusions
From 2009 to 2023, the number of HIV tests increased in Jiading District, mainly through pre-operation and blood transfusion (products) as well as premarital and antenatal periods. The HIV positive rate was the highest in VCT clinics.
5.Effect of Osteoking on Inflammatory Injury and NF-κB/NFATc1 Signaling Pathway in Model Mice with Postmenopausal Osteoporosis
Tiantian YU ; Ruibing FENG ; Qing WANG ; Chaowen LI ; Jiahao CHEN ; Ruixuan JIANG ; Yinshuai DING ; Yong HUANG ; Hao HU
Chinese Journal of Experimental Traditional Medical Formulae 2024;30(10):62-69
ObjectiveTo explore the possible mechanism of Osteoking (OK) on postmenopausal osteoporosis (PMOP). MethodForty adult female mice were randomly divided into a sham operation (Sham) group, osteoporosis model (OVX) group, estradiol intervention (E2) group, and OK group, with 10 mice in each group. The modeling was completed by conventional back double incision ovariectomy, and the corresponding drugs were given one week later. After 12 weeks, the body mass and uterine index of mice were measured, and the pathological changes of bone tissue and the number of osteoclasts (OCs) were determined by hematoxylin-eosin (HE) and tartrate-resistant acid phosphatase (TRAP) staining, respectively. Bone mineral density (BMD), trabecular number (Tb.N), trabecular separation (Tb.Sp), and bone volume fraction (BV/TV) were measured by microcomputed tomography (Micro-CT). The maximum load of the femur was detected by a three-point bending test. The contents of tumor necrosis factor-α (TNF-α) and bone resorption marker C-terminal telopeptide of type Ⅰ collagen (CTX-1) were measured by enzyme linked immunosorbent assay (ELISA). The protein expression levels of nuclear factor-kappa B p65 (NF-κB p65), phosphorylated nuclear factor-kappa B p65 (p-NF-κB p65), nuclear factor kappa B inhibitor alpha (IκBα), phosphorylated nuclear factor kappa B alpha (p-IκBα), nuclear factor of activated T cells 1 (NFATc1), and proto-oncogene (c-Fos) were detected by Western blot. The mRNA expressions of OCs-related specific genes matrix metalloproteinase-9 (MMP-9), NFATc1, TRAP, cathepsin K (CTSK), and c-Fos were detected by real-time fluorescence quantitative polymerase chain reaction (Real-time PCR). ResultCompared with the Sham group, the uterine index decreased significantly in the OVX group, and the body mass (BMI) increased significantly. The structure of bone trabeculae was completely damaged, and the number of OCs increased. BMD, Tb.N, BV/TV, and maximum load decreased, while Tb.Sp was up-regulated. The levels of TNF-α and CTX-1 in serum were up-regulated. The protein expressions of c-Fos, p-NF-κB p65/NF-κB p65, NFATc1, and p-IκBα/IκBα were increased. The mRNA expressions of NFATc1, c-Fos, CTSK, TRAP, and MMP-9 were up-regulated (P<0.05, P<0.01). Compared with the OVX group, the body mass of the OK and E2 groups decreased, and the uterine index increased. The bone trabeculae increased, and the number of OCs decreased. BMD, Tb.N, BV/TV, and maximum load increased, while Tb.Sp decreased. The levels of TNF-α and CTX-1 in serum were decreased. The protein expressions of c-Fos, p-NF-κB p65/NF-κB p65, NFATc1, and p-IκBα/IκBα were decreased, and the mRNA expressions of NFATc1, c-Fos, CTSK, TRAP, and MMP-9 were decreased (P<0.05, P<0.01). ConclusionOK can inhibit the NF-κB/NFATc1 signaling pathway and reduce bone mass loss by reducing the level of inflammatory injury factors in PMOP mice, which is one of the mechanisms for treating PMOP.
6.Correlation study of transcranial sonography combined with serum biomarkers and cognitive status in patients with Parkinson′s disease
Hai WANG ; Yingchun ZHANG ; Changwei DING ; Caishan WANG ; Yujing SHENG ; Xiaofang CHEN ; Ying ZHANG ; Min YANG ; Pan MAO ; Yong YANG ; Ping FENG ; Chengjie MAO ; Jing CHEN ; Chunfeng LIU
Chinese Journal of Ultrasonography 2024;33(6):512-518
Objective:To explore the correlation between transcranial sonography (TCS) combined with serum homocysteine (Hcy), blood glucose, blood lipids, the cognitive status of Parkinson′s disease (PD) patients, and to analyze the clinical application value of these parameters in assessing the cognitive status of PD patients.Methods:A total of 152 PD patients admitted to the Second Affiliated Hospital of Soochow University from January 2020 to June 2023 were retrospectively collected as the PD group, and 101 healthy examinees matched for age and gender during the same period were selected as control group. Clinical data [age, gender, duration of illness, Montreal Cognitive Assessment (MoCA) score, Mini-Mental State Examination (MMSE) score, Unified Parkinson′s Disease Rating Scale Part Ⅲ (UPDRS-Ⅲ) score, Hoehn-Yahr (H-Y) stage, etc.], serum tests (Hcy, blood glucose, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein concentration), and TCS examination results (third ventricular width, midbrain area, peak systolic velocity of bilateral middle cerebral arteries, bilateral middle cerebral artery resistance index, bilateral substantia nigra hyperechoic area) were collected. The two groups were divided into pure PD group and PD group with elevated Hcy, pure control group and control group with elevated Hcy, based on an Hcy concentration threshold of ≥15 μmol/L. The differences in the above parameters among the four groups were compared. The correlation between Hcy and cognitive status (MoCA score, MMSE score) of PD patients and the above parameters were analyzed.Results:The MoCA score and MMSE score of the PD group with elevated Hcy were lower than those of the pure PD group, and the UPDRS-Ⅲ score and H-Y stage were higher than those of the pure PD group (all P<0.001). The order of Hcy concentration from high to low was PD group with elevated Hcy, pure Hcy elevation group, pure PD group, and pure control group. The differences in serum data and TCS data among the four groups were statistically significant (all P<0.001). Spearman correlation analysis showed: ①In the PD group, the concentration of Hcy was positively correlated with glucose concentration, H-Y stage, low-density lipoprotein concentration, right middle cerebral artery resistance index, UPDRS-Ⅲ score, total cholesterol concentration, triglyceride concentration, left middle cerebral artery resistance index, third ventricular width, and age ( rs=0.422, 0.350, 0.348, 0.334, 0.325, 0.300, 0.293, 0.283, 0.221, 0.164, all P<0.05); Hcy concentration was negatively correlated with midbrain area, MMSE score, MoCA score, peak systolic velocity of right middle cerebral artery, peak systolic velocity of left middle cerebral artery, and high-density lipoprotein concentration ( rs=-0.328, -0.282, -0.245, -0.229, -0.224, -0.192, all P<0.05). ②Clinical data, serum data, and TCS data of PD patients were all correlated with MoCA score and MMSE score, with midbrain area showing the largest positive correlation ( rs=0.524, 0.516; both P<0.05) and H-Y stage showing the largest negative correlation( rs=-0.490, -0.468; both P<0.05). Conclusions:PD patients with elevated Hcy have lower cognitive scores than pure PD patients. The correlation between Hcy concentration and blood glucose concentration is the highest in PD patients, followed by H-Y stage. The cognitive scores of PD patients are most correlated with midbrain area and unrelated to substantia nigra hyperechoic area. Lowering serum Hcy concentration in PD patients may be one of the ways to delay cognitive impairment.
7.Application of polyetheretherketone rod semi-rigid pedicle screw internal fixation in lumbar non-fusion surgery
Tao LIU ; Xing YU ; Jian-Bin GUAN ; Yong-Dong YANG ; He ZHAO ; Ji-Zhou YANG ; Yi QU ; Feng-Xian WANG ; Ding-Yan ZHAO ; Zi-Yi ZHAO
China Journal of Orthopaedics and Traumatology 2024;37(7):676-683
Objective To investigate the effect of Polyetheretherketone(PEEK)rod semi-rigid pedicle screw fixation sys-tem in lumbar spine non-fusion surgery.Methods A total of 74 patients with tow-level lumbar degenerative diseases who un-derwent surgery from March 2017 to December 2019 were divided into PEEK rod group and titanium rod group.In the PEEK rod group,there were 34 patients,including 13 males and 21 females,aged from 51 to 79 years old with an average of(62.4±6.8)years old;There were 1 patient of L1-L3 segments,7 patients of L2-L4 segments,20 patients of L3-L5 segments and 6 pa-tients of L4-S1 segments.In the titanium rod group,there were 40 patients,including 17 males and 23 females,aged from 52 to 81 years old with an average of(65.2±7.3)years old;There were 3 patient of L1-L3 segments,11 patients of L2-L4 segments,19 patients of L3-L5 segments and 7 patients of L4-S1 segments.The general conditions of operation,such as operation time,intraoperative blood loss,postoperative drainage was recorded.The visual analogue scale(VAS)for low back pain and Os-westry disability index(ODI)were compared in preoperatively and postoperatively(3 months,12 months and last follow-up)between two groups.The change of range of motion(ROM)was observed by flexion and extension x-ray of lumbar Results All patients successfully completed the operation.The follow-up time ranged from 22 to 34 months with an average of(26.8±5.6)months.The operative time(142.2±44.7)min and intraoperative blood loss(166.5±67.4)ml in PEEK group were lower than those in titanium group[(160.7±57.3)min、(212.8±85.4)ml](P<0.05).There was no significant differences in postoperative drainage between the two groups(P>0.05).At the final follow-up visit,in PEEK group and titanium group VAS of low back pain[(0.8±0.4)points vs(1.0±0.5)points],VAS for leg pain[(0.7±0.4)points vs(0.8±0.5)points]and ODI[(9.8±1.6)%vs(12.1±1.5)%]were compared with preoperative[(5.8±1.1)points vs(6.0±1.1)points],[(7.2±1.7)points vs(7.0±1.6)points],[(68.5±8.9)%vs(66.3±8.2)%]were significantly different(P<0.05).There was no significant difference in VAS scores between the two groups at each postoperative time point(P>0.05).At 3 months after surgery,there was no difference in ODI between the two groups(P>0.05).There were significant differences in ODI between PEEK group and titanium rod group at 12 months[(15.5±2.1)%vs(18.4±2.4)%]and at the last follow-up[(9.8±1.6)%vs(12.1±1.5)%](P<0.05).The total range of motion(ROM)of lumbar decreased in both groups after surgery.At 12 months after surgery and the last follow-up,the PEEK group compared with the titanium rod group,the total range of motion of lumbar was statistically significant(P<0.05).The range of motion(ROM)of the fixed segments decreased in both groups after surgery.The ROM of the fixed segments in PEEK group decreased from(9.5±4.6)° to(4.1±1.9)° at the last follow-up(P<0.05),which in the titanium rod group was de-creased from(9.8±4.3)°to(0.9±0.5)° at the last follow-up(P<0.05).The range of motion(ROM)of upper adjacent segment increased in both groups,there was statistical significance in the ROM of upper adjacent segment between the two groups at 12 months after surgery and the last follow-up,(P<0.05).There was no screw loosening and broken rods in both groups during the follow-up period.Conclusion The PEEK rod semi-rigid pedicle screw internal fixation system used in lumbar non-fusion surgery can retain part of the mobility of the fixed segment,showing comparable short-term clinical efficacy to titanium rod fu-sion.PEEK rod semi-rigid pedicle screw internal fixation system is a feasible choice for the treatment of lumbar spine degener-ative diseases,and its long-term efficacy needs further follow-up observation.
8.Evaluation of the Promoter Activity of the CHO Cell Expression System Based on Site-specific Integration
Chen LU ; Zi-Yu WANG ; Yan-Fei CAI ; Yong-Qiang DENG ; Jian JIN ; Xue-Feng DING ; Yun CHEN
Chinese Journal of Biochemistry and Molecular Biology 2024;40(10):1400-1408
In industrial production,the expression level of drug proteins in Chinese hamster ovary cells(CHO)is influenced by many factors:the regulatory elements on transcription and translation,the ge-nomic integration sites,and the expression system.Transcription,as the first step of gene expression,largely affects protein expression,and the promoter plays a crucial role in the initiation of transcription.Most of the promoters were screened through transient transfection or random integration,but the presence of unclear copy number or random integration sites makes it difficult to accurately evaluate the promoter activity.To some extent,site-specific integration can reduce the impact of positional effects on exogenous genes and may potentially increase the expression level of exogenous genes.In the early stage of our re-search,multiple sites that can stably express exogenous proteins were identified and verified in the CHO cell genome.In this study,one of these sites(2c6)was selected for the evaluation of promoter activity.The CRISPR/Cas9 gene editing technique was used to site-specifically integrate the reporter gene(EG-FP)regulated by the simian virus early promoter(SV40),mouse elongation factor-1α(mEF-1α),chicken β-actin(cACTB)promoter,and human phosphoglycerate kinase promoter(hPGK)into the 2c6 site,respectively.The mean fluorescence intensity of the cells was analyzed by flow cytometry,and the mRNA level of EGFP was detected by qPCR to comprehensively evaluate the activity of the promoter.The results showed that the activities of the mEF-1α and mACTB promoters were better than those of SV40 and hPGK.The results of the secondary flow cytometry sorting showed that site-specific integration can more accurately evaluate the activity of the promoter in the CHO cell expression system.
9.Qualitative and quantitative analysis of chemical components of Dracocephalum moldavica based on UPLC-Q-TOF-MS/MS and UPLC.
Ming-Lei XU ; Hui-Min GAO ; Yong-Xin ZHANG ; Zhi-Jian LI ; Yang DING ; Qing-Rong WANG ; Shi-Xia HUO ; Wei-Hong FENG ; Yu-Tong KANG ; Liang-Mian CHEN ; Zhi-Min WANG
China Journal of Chinese Materia Medica 2024;49(23):6352-6367
Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS/MS) was used to rapidly identify the chemical components in Dracocephalum moldavica, and UPLC was employed to determine the content of its main components. MS analysis was performed using an electrospray ionization(ESI) source and data were collected in the negative ion mode. By comparing the retention time and mass spectra of reference compounds, and using a self-built compound database and the PubChem database, 68 compounds were identified from D. moldavica, including 36 flavonoids, 22 phenylpropanoids, 4 phenols, and 6 other compounds. On this basis, a UPLC quantitative method was established to simultaneously determine 8 main components, i.e., luteolin-7-O-glucuronide, apigenin-7-O-glucuronide, rosmarinic acid, diosmetin-7-O-glucuronide, tilianin, acacetin-7-O-glucuronide, acacetin-7-O-(6″-O-malonyl)-glucoside, and acacetin. A Waters ACQUITY BEH C_(18) column(2.1 mm × 100 mm, 1.7 μm) was used, with acetonitrile and a water solution containing 0.1% formic acid and 0.1% phosphoric acid as the mobile phase for gradient elution. The detection wavelength was set at 330 nm, with a flow rate of 0.4 mL·min~(-1), and the column temperature was maintained at 35 ℃. The 8 components demonstrated good linearity(r≥0.999 9) over a wide mass concentration range(50 or 100 times). The average recovery rate ranged from 97.5% to 105.1%, and the relative standard deviations(RSDs) were 0.90% to 3.4%(n= 6), indicating that the method was simple, accurate, and reliable. In 17 batches of D. moldavica samples, the content of these 8 components ranged from 0.405 to 2.10, 0.063 to 0.342, 0.446 to 2.43, 0.415 to 1.47, 1.57 to 4.34, 0.173 to 0.386, 1.00 to 5.40, and 0.069 to 0.207 mg·g~(-1), respectively. These results indicate significant differences in the internal quality of the samples, highlighting the need for strict quality control to ensure their pharmacodynamic efficacy. This study provides a scientific basis for the rapid discovery of pharmacodynamic substances, comprehensive quality control, and the formulation or revision of quality standards for D. moldavica.
Tandem Mass Spectrometry/methods*
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Chromatography, High Pressure Liquid/methods*
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Drugs, Chinese Herbal/chemistry*
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Lamiaceae/chemistry*
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Flavonoids/chemistry*
10.Three-dimensional finite element analysis of cement flow in abutment margin-crown platform switching.
Meng En OU ; Yun DING ; Wei Feng TANG ; Yong Sheng ZHOU
Journal of Peking University(Health Sciences) 2023;55(3):548-552
OBJECTIVE:
To analyze the cement flow in the abutment margin-crown platform switching structure by using the three-dimensional finite element analysis, in order to prove that whether the abutment margin-crown platform switching structure can reduce the inflow depth of cement in the implantation adhesive retention.
METHODS:
By using ANSYS 19.0 software, two models were created, including the one with regular margin and crown (Model one, the traditional group), and the other one with abutment margin-crown platform switching structure (Model two, the platform switching group). Both abutments of the two models were wrapped by gingiva, and the depth of the abutment margins was 1.5 mm submucosal. Two-way fluid structure coupling calculations were produced in two models by using ANSYS 19.0 software. In the two models, the same amount of cement were put between the inner side of the crowns and the abutments. The process of cementing the crown to the abutment was simulated when the crown was 0.6 mm above the abutment. The crown was falling at a constant speed in the whole process spending 0.1 s. Then we observed the cement flow outside the crowns at the time of 0.025 s, 0.05 s, 0.075 s, 0.1 s, and measured the depth of cement over the margins at the time of 0.1 s.
RESULTS:
At the time of 0 s, 0.025 s, 0.05 s, the cements in the two models were all above the abutment margins. At the time of 0.075 s, in Model one, the gingiva was squeezed by the cement and became deformed, and then a gap was formed between the gingiva and the abutment into which the cement started to flow. In Model two, because of the narrow neck of the crown, the cement flowed out from the gingival as it was pressed by the upward counterforce from the gingival and the abutment margin. At the time of 0.1 s, in Model one, the cement continued to flow deep inside with the gravity force and pressure, and the depth of the cement over the margin was 1 mm. In Model two, the cement continued to flow out from the gingival at the time of 0.075 s, and the depth of the cement over the margin was 0 mm.
CONCLUSION
When the abutment was wrapped by the gingiva, the inflow depth of cement in the implantation adhesive retention can be reduced in the abutment margin-crown platform switching structure.
Finite Element Analysis
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Cementation/methods*
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Gingiva
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Crowns
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Dental Abutments
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Dental Cements
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Dental Stress Analysis


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