Aim To study the proliferation,invasion and migration ability of Quaking(QKI)in gastric cancer(GC)via elucidating the molecular mechanisms associated with QKI in the occurrence and development of GC through bioinformatics.Methods Differential expression analysis of QKI was performed across vari-ous human cancer samples by merging data from the TCGA and GTEx databases.The correlation was ana-lyzed between QKI protein expression and tumor muta-tion burden(TMB)score,microsatellite instability(MSI)score,and ESTIMATE score,and the correla-tion was also explored between QKI protein expression and overall survival(OS),disease free survival(DFS),and progression free survival(PFS).EMT related genes that could encode DECircRNAs were ob-tained through bioinformatics analysis to construct a QKI-EMT-circRNAs regulatory network.The differenti-ally expressed circRNAs and EMT related genes in TMK1 cells were verified.The proliferation,invasion and migration ability of the QKI was studied by using the knockdown system.Results QKI was differential-ly expressed in the vast majority of tumors and was closely related to TMB,MSI,and tumor microenviron-ment(TME);QKI emerged as a high-risk factor for predicting OS,DFS,and PFS in individuals with com-mon human cancers.QKI regulated the splicing of 6 EMT related gene transcripts to form eight circRNAs,all of which were significantly associated with the prog-nosis of gastric cancer patients.Cell experiments showed that compared to normal gastric epithelial cells,only hsa_ccirc_0004015,CALD1,and CDK14 were down-regulated in TMK1 cells.Knocking down QKI inhibited the proliferation,invasion and migration ability of TMK1 cells.Conclusion QKI exerts regu-latory control over the transcription of six EMT-related genes,resulting in the formation of circRNAs,thereby promoting the pathogenesis and progression of GC.QKI is highly expressed in TMK1 cells,and knock-down of QKI can inhibit the proliferation,invasion and migration ability of TMK1 cells.

Objective To explore the effect of activation of mammalian target of rapmycin complex 2(mTORC2)/Akt signaling pathway on dopaminergic neurons and behavior in 6-hydroxydopamine (6-OHDA) model mice and its possible mechanism. Methods Selecting 36 mice which The Nestin-CreERTM and ROSA26-LacZ reporter genes were detected at the same time in 3-month-old male C57BL/6J mice weighing 20-25 g divideng them into 4 gruops, NS+ corn oil group, 6-OHDA+corn oil group, 6-OHDA+PP242 group and 6-OHDA+A-443654 group, and 6-OHDA was injected into the right striatum of the brain to replicate the Parkinson’s disease (PD) model of mice, and then daily intraperitoneal injection of mTORC2/Akt signaling pathway agonist A-443654 or inhibitor PP242. Serum interleukin-1β (IL-1β) and tumor necrosis factor-α(TNF-α)levels were measured by enzyme-linked immunosorbent assay. Immunohistochemistry and immunofluorescence staining were performed to investigate the change of microglia, dopaminergic neurons as well as neural progenitor cells (NPCs). Western blotting was used to detect the expression of related protein of mTORC2/Akt signaling pathway including rictor, p-Akt and regulated in development and DNA dgmage responses 1(REDD1) and the interaction between them were verified by immunoprecipitation. Finally, the behavioral performance of each group of mice was observed. Results With the activation of microglia and the increase of inflammatory factors in PD model mice, the number of dopaminergic neurons in the substantia nigra(SN) decreased significantly, and the motor function of the mice was impaired, but the number of NPCs increased significantly compared with the control mice, mTORC2/Akt signaling pathway related protein expression was also significantly up-regulated. A-443654 treatment further up-regulated the expression of these proteins, meanwhile the indicators mentioned above were ameliorated. However, the inhibitor PP242 treatment group showed completely opposite result with the agonist group. Conclusion A-443654 can promote the proliferation of NPCs and the number of new-born dopaminergic neurons by up-regulating related proteins of mTORC2/Akt signaling pathway, and reducing the activation of microglia and the level of inflammation factors, which ultimately lead to the amelioration of SN-striatal dopaminergic neurons and behavioral performance in PD model mice.

Objective: To investigate the effects of lncRNA DRAIC on proliferation, apoptosis, migration and invasion of lung adenocarcinoma cells and its mechanism. Methods: Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) was used to detect the expression of DRAIC in lung cancer tissues and corresponding adjacent normal tissues of 40 patients with lung adenocarcinoma who underwent surgery in Tangshan People's Hospital from 2019 to 2020. Lung adenocarcinoma cells A549 and H1299 were cultured in vitro and divided into si-NC group, si-DRAIC group, miR-NC group, let-7i-5p mimics group, si-DRAIC+ inhibitor-NC group, and si-DRAIC+ let-7i-5p inhibitor group. CCK-8 method and clone formation experiment were used to detect cell proliferation. Flow cytometry was used to detect cell apoptosis. Transwell array was used to detect the cell migration and invasion. Western blot was used to detect the protein expressions of Caspase-3, Caspase-9, Bcl-2 and Bax. The double luciferase reporter gene experiment was used to verify the regulatory relationship between DRAIC and let-7i-5p. Independent sample t test was used for comparison between two groups, one-way ANOVA was used for comparison between multiple groups, and Pearson correlation analysis was used for correlation analysis. Results: Compared with adjacent tissues, the expression level of DRAIC in lung adenocarcinoma tissues increased (P<0.05), but the expression level of let-7i-5p decreased (P<0.05). The expression levels of DRAIC and let-7i-5p in lung adenocarcinoma tissues were negatively correlated (r=-0.737, P<0.05). The absorbance value of A549 and H1299 cells in the si-DRAIC group at 48, 72 and 96 hours were lower than those in the si-NC group (P<0.05), the number of clones formed [(91.00±6.08 vs. 136.67±6.51); (50.67±1.53 vs. 76.67±4.51)], the number of migration [(606.67±31.34 vs. 960.00±33.06); (483.33±45.96 vs. 741.67±29.67)], the number of invasion [(185.00±8.19 vs. 447.33±22.05); (365.00±33.87 vs. 688.00±32.97)] were lower than those in the si-NC group (P<0.05). However, the apoptosis rates of cells [(13.43±2.79)% vs. (4.53±0.42)%; (23.77±1.04)% vs. (6.60±1.42)%] were higher than those in the si-NC group (P<0.05). The protein expressions of Caspase-3, Caspase-9 and Bax in si-DRAIC group were higher than those in si-NC group, and the protein expression of Bcl-2 was lower than that in si-NC group (P<0.05). DRAIC is located in the cytoplasm. DRAIC targeted and negatively regulated the expression of let-7i-5p. The absorbance values of A549 and H1299 cells in the let-7i-5p mimics group at 48, 72 and 96 hours were lower than those in the miR-NC group (P<0.05), the number of clones formed [(131.33±14.47 vs. 171.33±6.11); (59.33±4.93 vs. 80.33±7.09)], the number of migration [(137.67±3.06 vs. 579.33±82.03); (425.00±11.14 vs. 669.33±21.13)], the number of invasion [(54.00±4.36 vs. 112.67±11.59); (80.00±4.58 vs. 333.33±16.80)] were lower than those in the miR-NC group (P<0.05). However, the apoptosis rates of cells [(14.57±1.10)% vs. (6.97±1.11)%; (23.97±0.42)% vs. (7.07±1.21)%] were higher than those in the miR-NC group (P<0.05). The protein expressions of Caspase-3, Caspase-9 and Bax in let-7i-5p mimics group were higher than those in miR-NC group, and the protein expression of Bcl-2 was lower than that in miR-NC group (P<0.05). The absorbance values of A549 and H1299 cells in the si-DRAIC+ let-7i-5p inhibitor group at 48, 72 and 96 hours were higher than those in the si-DRAIC+ inhibitor-NC group (P<0.05), the number of clones formed [(82.00±5.29 vs. 59.00±5.57); (77.67±4.93 vs. 41.33±7.57)], the number of migration [(774.33±35.81 vs. 455.67±19.04); (569.67±18.72 vs. 433.67±16.77)], the number of invasion [(670.33±17.21 vs. 451.00±17.52); (263.67±3.06 vs. 182.33±11.93)] were higher than those in the si-DRAIC+ inhibitor-NC group (P<0.05). However, the apoptosis rates of cells [(7.73±0.45)% vs. (19.13±1.50)%; (8.00±0.53)% vs. (28.40±0.53)%] were lower than those in the si-NC group (P<0.05). The protein expressions of Caspase-3, Caspase-9 and Bax in si-DRAIC+ let-7i-5p inhibitor group were higher than those in si-DRAIC+ inhibitor-NC group, and the protein expression of Bcl-2 was lower than that in si-DRAIC+ inhibitor-NC group (P<0.05). Conclusion: DRAIC is highly expressed in lung adenocarcinoma, and DRAIC promotes the proliferation, migration and invasion of lung adenocarcinoma cells and inhibits apoptosis by targeting let-7i-5p.
Humans ; Adenocarcinoma/genetics* ; Apoptosis/genetics* ; bcl-2-Associated X Protein/metabolism* ; Caspase 3/metabolism* ; Caspase 9/metabolism* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Lung/metabolism* ; MicroRNAs/metabolism* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; RNA, Long Noncoding/genetics*

Objective: To investigate the clinical features and gene variation characteristics of children with dynein cytoplasmic 1 heavy chain 1 (DYNC1H1) gene associated spinal muscular atrophy with lower extremity predominant (SMALED) 1. Methods: The clinical data of 4 SMALED1 children admitted to Peking University First Hospital from December 2018 to May 2021, who were found to have pathogenic variation of DYNC1H1 gene through genetic testing, except for other genes known to be related to motor retardation, were retrospectively summarized to analyze the phenotype and genotype characteristics. Results: There were 3 males and 1 female. The age of onset was 1 year, 1 day, 1 day and 4 months, respectively. The age of diagnosis was 4 years and 10 months, 9 months, 5 years and 9 months, and 3 years and 1 month, respectively. The clinical manifestations were muscle weakness and muscular atrophy of lower limbs, 2 cases with foot deformity, 1 case with early non progressive joint contracture, 1 case with hip dislocation and 1 case with mental retardation. De novo heterozygous missense variations in DYNC1H1 gene were found in all 4 children. According to the rating of American College of medical genetics and genomics, they were all possible pathogenic and pathogenic variations, with p.R598C, p.P776L, p.Y1109D variations had been reported, and p.I1086R variation had not been reported. Conclusions: For those with unexplained lower limb muscle weakness, muscle atrophy, joint contracture and foot deformity, upper limb motor ability related retention, with or without mental retardation, as well as the motor ability progresses slowly, it is necessary to consider the possibility of SMALED1 and the detection of DYNC1H1 gene when necessary.
Female ; Male ; Humans ; Intellectual Disability ; Retrospective Studies ; Muscular Atrophy, Spinal/genetics* ; Lower Extremity ; Muscle Weakness ; Muscular Atrophy ; Contracture ; Cytoplasmic Dyneins/genetics*

Objective: To analyze the follow-up and clinical effect of multidisciplinary treatment on the children with spinal muscular atrophy (SMA). Methods: The clinical data including nutritional status, respiratory function, bone health and motor function of 45 children with SMA who received multidisciplinary management 1-year follow-up in the Children's Hospital, Zhejiang University School of Medicine from July 2019 to October 2021 were retrospectively collected. Comparisons before and after management were performed using paired-samples t-test or Wilcoxon rank-sum test, etc. Results: The age of 45 patients (25 boys and 20 girls) was 50.4 (33.6, 84.0) months at the enrollment, with 6 cases of type 1, 22 cases of type 2, and 17 cases of type 3 respectively. After the multidisciplinary management, the cases of SMA patients with malnutrition decreased from 22 to 12 (P=0.030), the level of vitamin D were significantly increased ((45±17) vs. (48±14) nmol/L, t=-4.13, P<0.001). There was no significant difference in the forced vital capacity %pred, the forced expiratory volume at 1 second %pred, and the peak expiratory flow %pred ((76±19)% and (76±21)%, (81±18)% and (79±18)%, (81±21)% and (78±17)%; t=-0.24, 1.36, 1.21; all P>0.05). The Cobbs angle of scoliosis also improved significantly (8.0°(0°, 13.0°) vs. 10.0°(0°, 18.5°), Z=-3.01, P=0.003). The Hammersmith functional motor scale expanded scores of children with SMA type 2 and type 3 both showed significant elevation (11.0 (8.0, 18.0) vs. 11.0 (5.0, 18.5) scores, 44.0 (36.5, 53.0) vs. 44.0 (34.0, 51.5) scores, Z=2.44, 3.11, P=0.015, 0.002). Conclusion: Multidisciplinary management is beneficial for delaying the progression of the multi-system impairments of SMA patients, such as malnutrition, restrictive ventilation dysfunction and scoliosis.
Child ; Male ; Female ; Humans ; Child, Preschool ; Scoliosis ; Retrospective Studies ; Follow-Up Studies ; Muscular Atrophy, Spinal ; Malnutrition

Objective: To study the effects of dihydromyricetin (DMY) on the proliferation, apoptosis and epithelial mesenchymal transition (EMT) of esophageal squamous cell carcinoma (ESCC) cell KYSE150 and KYSE410. Methods: KYSE150 and KYSE410 cells were treated with different concentrations of DMY (0, 25, 50, 100, 150, 200 μmol/L) for 24 hours. The median inhibition concentration (IC₅₀) values of KYSE150 and KYSE410 were detected by cell counting kit-8 (CCK-8) method. Then 0.5‰ dimethyl sulfoxide (DMSO) was used as control group, dihydromyricetin (DMY), dihydromyricetin and transforming growth factor-β1 (DMY+ TGF-β1), transforming growth factor-β1 (TGF-β1) were used as experimental group. Cell proliferation and apoptosis rates were measured by clonal formation and flow cytometry. Transwell invasion and wound healing assay were used to detect cell invasion and migration. The protein expression levels of Caspase-3, Caspase-9, Bcl-2, Bax, Smad2/3, phosphorylation-Smad2/3 (p-Smad2/3) and Vimentin were detected by western blot. Results: The IC₅₀ values of DMY on KYSE410 and KYSE150 cells were 100.51 and 101.27 μmol/L. The clone formation numbers of KYSE150 and KYSE410 in DMY group [(0.53±0.03) and (0.31±0.03)] were lower than those in DMSO group [(1.00±0.10) and (1.00±0.05), P<0.05]. The apoptosis rates of KYSE150 and KYSE410 cells in DMY group [(1.84±0.22)% and (2.80±0.07)%] were higher than those in DMSO group [(1.00±0.18)% and (1.00±0.07)%, P<0.05]. The invasion numbers of KYSE150 and KYSE410 cells in DMY group [(0.42±0.03) and (0.29±0.05)] were lower than those in DMSO group [(1.00±0.08) and (1.00±0.05), P<0.05]. The migration rates of KYSE150 and KYSE410 cells in DMY group [(0.65±0.14)% and (0.40±0.17)%] were lower than those in DMSO group [(1.00±0.10)% and (1.00±0.08)%, P<0.05]. The clone formation numbers of KYSE150 and KYSE410 in TGF-β1 group [(1.01±0.08) and (0.99±0.25)] were higher than those in DMY+ TGF-β1 group [(0.73±0.10) and (0.58±0.05), P<0.05]. The apoptosis rates of KYSE150 and KYSE410 cells in TGF-β1 group [(0.81±0.14)% and (1.18±0.10)%] were lower than those in DMY+ TGF-β1 group [(1.38±0.22)% and (1.85±0.04)%, P<0.05]. The invasion numbers of KYSE150 and KYSE410 cells in TGF-β1 group [(1.19±0.11) and (1.39±0.11)] were higher than those in DMY+ TGF-β1 group [(0.93±0.09) and (0.93±0.05), P<0.05]. The migration rates of KYSE150 and KYSE410 cells in TGF-β1 group [(1.87±0.19)% and (1.32±0.04)%] were higher than those in DMY+ TGF-β1 group [(0.86±0.16)% and (0.77±0.12)%, P<0.05]. The protein expression levels of Bax, Caspase-3 and Caspase-9 in KYSE150 and KYSE410 cells in DMY group were higher than those in DMSO group, while the protein expression level of Bcl-2 was lower than that in DMSO group (P<0.05). The protein expression levels of p-Smad2/3, Smad2/3 and Vimentin in KYSE150 and KYSE410 cells in DMY group were lower than those in DMSO group (P<0.05). The protein expression levels of Bax, Caspase-3 and Caspase-9 in KYSE150 and KYSE410 cells in TGF-β1 group were lower than those in DMY+ TGF-β1 group, and the protein expression level of Bcl-2 was higher than that in DMY+ TGF-β1 group (P<0.05). The protein expression levels of Bax, Caspase-3 and Caspase-9 in KYSE150 and KYSE410 cells in DMY+ TGF-β1 group were lower than those in DMY group, and the protein expression level of Bcl-2 was higher than that in DMY group (P<0.05). The protein expression levels of p-Smad2/3, Smad2/3 and Vimentin in KYSE150 and KYSE410 cells in TGF-β1 group were higher than those in DMY+ TGF-β1 group (P<0.05). Conclusion: DMY can inhibit the proliferation and EMT of ESCC mediated by TGF-β1 and promote cell apoptosis.
Apoptosis ; Caspase 3/metabolism* ; Caspase 9/metabolism* ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Dimethyl Sulfoxide/pharmacology* ; Epithelial-Mesenchymal Transition ; Esophageal Neoplasms/metabolism* ; Esophageal Squamous Cell Carcinoma ; Flavonols ; Humans ; Signal Transduction ; Transforming Growth Factor beta1/pharmacology* ; Vimentin/metabolism* ; bcl-2-Associated X Protein/pharmacology*

Nonalcoholic fatty liver disease (NAFLD) is regarded as the most common liver disease with no approved therapeutic drug currently. Silymarin, an extract from the seeds of Silybum marianum, has been used for centuries for the treatment of various liver diseases. Although the hepatoprotective effect of silybin against NAFLD is widely accepted, the underlying mechanism and therapeutic target remain unclear. In this study, NAFLD mice caused by methionine-choline deficient (MCD) diet were orally administrated with silybin to explore the possible mechanism and target. To clarify the contribution of peroxisome proliferator-activated receptor α (PPARα), PPARα antagonist GW6471 was co-administrated with silybin to NAFLD mice. Since silybin was proven as a PPARα partial agonist, the combined effect of silybin with PPARα agonist, fenofibrate, was then evaluated in NAFLD mice. Serum and liver samples were collected to analyze the pharmacological efficacy and expression of PPARα and its targets. As expected, silybin significantly protected mice from MCD-induced NAFLD. Furthermore, silybin reduced lipid accumulation via activating PPARα, inducing the expression of liver cytosolic fatty acid-binding protein, carnitine palmitoyltransferase (Cpt)-1a, Cpt-2, medium chain acyl-CoA dehydrogenase and stearoyl-CoA desaturase-1, and suppressing fatty acid synthase and acetyl-CoA carboxylase α. GW6471 abolished the effect of silybin on PPARα signal and hepatoprotective effect against NAFLD. Moreover, as a partial agonist for PPARα, silybin impaired the powerful lipid-lowering effect of fenofibrate when used together. Taken together, silybin protected mice against NAFLD via activating PPARα to diminish lipid accumulation and it is not suggested to simultaneously take silybin and classical PPARα agonists for NAFLD therapy.

Objective:To investigate clinical significance of Presepsin(soluble CD14 subtype) in the diagnosis and condition assessment of sepsis in children compared with traditional biomarkers.Methods:For the prospective study, 102 children with sepsis admitted to the PICU of the Children′s Hospital of the Capital Institute of Pediatrics from January 2017 to December 2018 were selected, including 57 cases in the sepsis group, 45 cases in the severe sepsis/septic shock group and 25 cases in the non-infectious systemic inflammatory response syndrome(SIRS group), and 35 children with healthy physical examination during the same period as the control group.The sepsis group was further divided into the survival group( n=86)and the death group( n=16)based on the 28-day mortality.The data collected included serum Presepsin, procalcitonin(PCT), C-reaction protein(CRP) and interleukin(IL)-6 levels on days 1, 3 and 7 of admission, and compared with paediatric critical case scores. Results:(1)The levels of serum Presepsin [12.43(7.21, 15.07) ng/mL], PCT [23.00(5.70, 87.00) ng/mL], CRP [160.0(105.5, 200.0) mg/L], IL-6 [1 000.0(125.0, 1, 000.0) pg/mL] were significantly higher than those in the sepsis, SIRS and control groups( P<0.001). (2) The area under the ROC curve(AUC) values for Presepsin, PCT, and IL-6 subjects on day 1 of admission were 0.856, 0.812, and 0.516, respectively.The sensitivity of Presepsin at a cut-off value of 4.40 ng/mL for the diagnosis of sepsis was 81.1% and the specificity was 72.3%, which would significantly higher diagnostic efficacy of the combination of Presepsin, PCT and IL-6.(3) There was a significant difference between the survival and death groups in Presepsin( P<0.001), and Presepsin was significantly higher in the death group on days 3 and 7 than those in the survival group(both P<0.001); IL-6 was significantly higher in the death group on day 3 than that in the survival group( P=0.04); the differences in PCT and CRP between the death and survival groups at all time points were not statistically significant(both P>0.05 ). (4) The AUCs of inflammatory factors on days 1, 3 and 7 to predict sepsis outcome were 0.597, 0.656 and 0.951 for Presepsin, 0.576, 0.613 and 0.655 for PCT and 0.726, 0.786 and 0.664 for IL-6, respectively.The diagnostic values of Presepsin on day 7 and IL-6 on days 1 and 3 were higher.The combination of Presepsin, PCT and IL-6 significantly improved the prognostic judgment of sepsis.(5) The difference between sepsis-related acute kidney injury(AKI) and non-AKI was not statistically significant when comparing Presepsin on day 1 and 3(all P>0.05). Presepsin levels on day 7 were significantly higher in children with sepsis-associated AKI than in those without AKI( P<0.001). Conclusion:Presepsin is a good biomarker for sepsis diagnosis in children, which is equivalent to PCT in the diagnosis of sepsis, superior to IL-6 and superior to PCT in the prognosis evaluation.Combined testing of Presepsin, PCT and IL-6 may improve the diagnosis of sepsis and the assessment of the condition in children.

OBJECTIVE: To investigate the correlation between the quadriceps cross-sectional area (CSA) and quadriceps muscle volume (QMV) at different horizontal levels from the upper edge of the patella, and to determine the best observation position. METHODS: Thigh magnetic resonance imaging (MRI) images of 22 Chinese young men [age: (29±6) years] with anterior cruciate ligament (ACL) rupture were examined. The CSA was measured at 18, 15, and 12 cm above the upper edge of the pate-lla (denoted by CSA-18, CSA-15 and CSA-12 respectively), and the QMV and CSA were determined by semiautomatic segmentation. A curve model was established to estimate QMV. Bland-Altman analysis was performed to determine the confidence limits of the volumes. RESULTS: On the unaffected side, the mean QMV was (1 944.45±323.77) cm³. The quadriceps CSA at the upper edge of the patella at 18, 15, and 12 cm was (80.80±12.16) cm², (77.53±12.03) cm², and (72.68±10.51) cm², respectively. The coefficients of determination (R²), ascertained using curve estimation models, for the 3 positions were 0.819, 0.755, and 0.684 (P < 0.001), and the standard deviations of the volume estimated value (SEE) were 7.4%, 8.7%, and 9.8%. The fitting equations of the three horizontal positions were all good, but the fitting degree of CSA-18 was the highest. The Bland-Altman scatter plot showed that the arithmetic means of the QMV at 18, 15 and 12 cm from the upper edge of the patella 0.8 cm³, -1.1 cm³, and 0.9 cm³ and 95% limits of agreement (LoA) were (-268.8, 270.5), (-315.2, 313.1), and (-355.7, 357.5), respectively. The estimated QMV was in good agreement with the measured value. The difference between the estimated CSA-18 and measured values was the smallest. The results on the affected side were consistent. CONCLUSION The correlation between QMV and CSA in the young men with the upper edge of patella as baseline was reliable and consistent. Among them, CSA-18 had the highest correlation with the QMV. However, different observation sites could be selected for different injuries of the quadriceps.
Adult ; Anterior Cruciate Ligament Injuries/surgery* ; Anterior Cruciate Ligament Reconstruction ; Humans ; Magnetic Resonance Imaging ; Male ; Patella ; Quadriceps Muscle/diagnostic imaging* ; Young Adult

OBJECTIVE: To investigate the effects of preparation height and cement space on the fit and retention of computer aided design (CAD)/computer aided manufacturing (CAM) zirconia crown, and to provide reference for the clinical design and fabrication of CAD/CAM crowns. METHODS: 3D printing system was used to fabricate resin abutment teeth with convergence angle of 2° and height of 1-3 mm. The models' optical impressions were collected by the three-shape scanner. Then, the cement spaces were set by Cradle CAD/CAM system at 10-50 μm to create an all-ceramic zirconia crown. The fit of the crowns was measured by using silicone rubber interstitial impression method. The retention of the crowns was measured by pull-off test with uniaxial tensile force after the crown was bonded. The data were analyzed by SPSS 22.0 soft-ware. RESULTS: When the preparation height was fixed, the fitness values of different cement space groups have statistical difference (P<
0.05), whereas the retention values of different cement space groups have no statistical difference (P>0.05). The fitness values of different preparation height groups have no statistical difference (P>0.05), and the retention values of different preparation height groups have statistical difference (P<0.05) when the cement space was fixed. No interaction was observed between the cement space and the preparation height (P>0.05). CONCLUSIONS When cradle CAD/CAM system is used to create a full crown in the clinic, the preparation height should be set to more than 3 mm, and the cement space should be set at 30 μm.
Computer-Aided Design ; Crowns ; Dental Porcelain ; Dental Prosthesis Design ; Zirconium