OBJECTIVE: To quantitatively evaluate the accuracy of data obtained from liquid-interference surfaces using an intraoral 3D scanner (IOS) integrated with a compressed airflow system, so as to provide clinical proof of accuracy for the application of the compressed airflow system-based scanning head in improving data quality on liquid-interference surfaces. METHODS: The study selected a standard model as the scanning object, adhering to the "YY/T 1818-2022 Dental Science Intraoral Digital Impression Scanner" guidelines, a standard that defined parameters for intraoral scanning. To establish a baseline for accuracy, the ATOS Q 12M scanner, known for its high precision, was used to generate true reference values. These true values served as the benchmark for evaluating the IOS performance. Building on the design of an existing scanner, a new scanning head was developed to integrate with a compressed airflow system. This new design aimed to help the IOS capture high-precision data on surfaces where liquid-interference, such as saliva, might otherwise degrade scanning accuracy. The traditional scanning method, without airflow assistance, was employed as a control group for comparison. The study included five groups in total, one control group and four experimental groups, to investigate the effects of scanning lens obstruction, airflow presence, liquid media, and the use of the new scanning head on scanning process and accuracy. Each group underwent 15 scans, generating ample data for a robust statistical comparison. By evaluating trueness and precision in each group, the study assessed the impact of the compressed airflow system on the accuracy of IOS data collected from liquid-interference surfaces. Additionally, we selected Elite and Primescan scanners as references for numerical accuracy values. RESULTS: The scanning accuracy on liquid-interference surfaces was significantly reduced in terms of both trueness and precision [Trueness: 18.5 (6.5) vs. 38.0 (6.7), P < 0.05; Precision: 19.1 (8.5) vs. 31.7 (15.0), P < 0.05]. The use of the new scanning head assisted by the compressed airflow system significantly improved the scanning accuracy [Trueness: 22.3(7.6) vs. 38.0 (6.7), P < 0.05; Precision: 25.8 (9.6) vs. 31.7 (15.0), P < 0.05]. CONCLUSION The scanning head based on the compressed airflow system can assist in improving the accuracy of data obtained from liquid-interference surfaces by the IOS.
Imaging, Three-Dimensional/methods* ; Humans ; Dental Impression Technique/instrumentation*

OBJECTIVE: To identify the role of gene silencing or overexpression of Nemo-like kinase (NLK) during the process of neural differentiation of human mesenchymal stem cells (hBMSCs), and to explore the effect of NLK downregulation by transfection of small interfering RNA (siRNA) on promoting neuralized tissue engineered bone regeneration. METHODS: NLK-knockdown hBMSCs were established by transfection of siRNA (the experimental group was transfected with siRNA silencing the NLK gene, the control group was transfected with control siRNA and labeled as negative control group), and NLK-overexpression hBMSCs were established using lentivirus vector transfection technique (the experimental group was infected with lentivirus overexpressing the NLK gene, the control group was infected with an empty vector lentivirus and labeled as the empty vector group). After neurogenic induction, quantitative real-time polymerase chain reaction (qPCR) was used to detect the expression of neural-related gene, and Western blot as well as immunofluorescence staining about several specific neural markers were used to evaluate the neural differentiation ability of hBMSCs.6-week-old male nude mice were divided into 4 groups: ① β-tricalcium phosphate (β-TCP) group, ② β-TCP+ osteogenic induced hBMSCs group, ③ β-TCP+ siRNA-negative control (siRNA-NC) transfection hBMSCs group, ④ β-TCP+ siRNA-NLK transfection hBMSCs group. Four weeks after the subcutaneous ectopic osteogenesis models were established, the osteogenesis and neurogenesis were detected by hematoxylin-eosin (HE) staining, Masson staining and tissue immunofluorescence assay. Statistical analysis was conducted by independent sample t test. RESULTS: After gene silencing of NLK by siRNA in hBMSCs, neural-related genes, including the class Ⅲ β-tubulin (TUBB3), microtubule association protein-2 (MAP2), soluble protein-100 (S100), nestin (NES), NG2 proteoglycan (NG2) and calcitonin gene-related peptide (CGRP), were increased significantly in NLK-knockdown hBMSCs compared with the negative control group(P < 0.05), and the expression levels of TUBB3 and MAP2 of the NLK silencing group were also increased. Oppositely, after NLK was overexpressed using lentivirus vector transfection technique, TUBB3, MAP2, S100 and NG2 were significantly decreased in NLK-overexpression hBMSCs compared with the empty vector group (P < 0.05), and the expression level of TUBB3 was also decreased. 4 weeks after the subcutaneous ectopic osteogenesis model was established, more mineralized tissues were formed in the β-TCP+ siRNA-NLK transfection hBMSCs group compared with the other three groups, and the expression of BMP2 and S100 was higher in the β-TCP+ siRNA-NLK transfection hBMSCs group than in the other groups. CONCLUSION Gene silencing of NLK by siRNA promoted the ability of neural differentiation of hBMSCs in vitro and promoted neuralized tissue engineered bone formation in subcutaneous ectopic osteogenic models in vivo in nude mice.
Bone Regeneration/genetics* ; Animals ; Mesenchymal Stem Cells/cytology* ; Humans ; RNA, Small Interfering/genetics* ; Tissue Engineering/methods* ; Cell Differentiation ; Mice, Nude ; Gene Silencing ; Mice ; Male ; Protein Serine-Threonine Kinases/genetics* ; Intracellular Signaling Peptides and Proteins/genetics* ; Transfection ; Cells, Cultured ; Lentivirus/genetics*

Objective:To investigate the survival rate and clinical failure reasons of onlay and occlusal veneer restorations retrospectively,and to put forward valuable suggestions for the selection of clinical in-dications.Methods:A total of 102 patients and 124 teeth treated by one of the authors from 2016 to 2019 were subjected to CAD/CAM lithium silicate reinforced glass-ceramic onlay or veneer restorations of premolars and molars,including 43 teeth with pulp vitality,81 endodontic treated teeth,and occlusal thickness of restoration was 1.5 mm.After four years of restoration,retrospective surveys were conducted to record the survival rate of restorations,the causes of restoration failure,and patient satisfaction rates,and the survival rate of restorations between vital teeth and endodontic treated teeth and among restored teeth was statistically analyzed by Chi-square test.Results:The survival rates of restorations on vital teeth and endodontic treated teeth were 95.5％and 90.0％,respectively,the average survival rate was 90.2％.The survival rates of vital teeth were higher than those of endodontic treated teeth without statis-tical difference.There was also no statistically significant difference among the tooth locations.The cau-ses of failure included the cracking of the restoration,the loss of the restoration,the fracture of the abut-ment teeth,secondary caries below the adjacent contact point,and food impaction caused by the loose-ning of the adjacent contact point.The overall patient satisfaction rate was 91.5％.Conclusion:The 4-year survival rate of glass-ceramic onlays and occlusal veneers is lower than that of the full crown restora-tion,and there are more complications than that of the single-crown restorations.The design of the resto-ration should be carefully selected based on the vitality of the abutment tooth and the remaining amount of tooth tissue.When there is too little tooth structure left,a post and crown should be selected for restora-tion.Adequate strength and thickness of the restoration should be ensured to prevent food impaction.Due to the small amount of abutment tooth preparation,it has the advantages of less stimulation of the pulp and periodontal tissue,and can be recommended as a trial restoration.

In fixed prosthodontics, clear exposure of the preparation margin is the prerequisite for obtaining accurate digital impressions and improving the marginal fit of restorations. To resolve the issues associated with the cord retraction technique, such as pain, acute injury, and prolonged procedural time, this study proposes a new technology for intraoral digital impression taking with pneumatic gingival retraction. The new scanning head blows a high-speed airflow that instantaneously separates the free gingiva, locally exposing the subgingival preparation margin. Combined with the farthest point preservation stitching algorithm based on the distance from the normal vector and high-speed laser scanning photography, it achieves global preparation edge data and gingival reconstruction, realizing painless, non-invasive, and efficient precise acquisition of the preparation margin. Using this new technique, a patient with a full porcelain crown restoration on a posterior tooth was treated. The digital impression revealed a clear margin of the preparation, and the crown made from this data has a good marginal fit.

Objective:To evaluate the clinical survival rates and influence factors of different types of resin-bonded fixed partial dentures (RBFPD) used in anterior missing teeth restoration.Methods:Ninety-three RBFPD were delivered to 92 patients [92 patients,43 males and 49 females, average age (46.1±12.8) years] who visited Peking University School and Hospital of Stomatology from January 2006 to December 2021 for restoration of 1 or 2 anterior missing teeth. Altogether 32 cases of glass fiber reinforced RBFPD, 39 cases of glass-based ceramic RBFPD and 22 cases of porcelain-fused-to-metal RBFPD were retrospectively analyzed. The complete survival rate, functional survival rate, patients′ satisfaction and color matching of the restorations were recorded and evaluated every year since the replacement with RBFPD. The Kaplan-Meier survival curve method was used for survival analysis, and the Log-rank analysis was used to compare the effect of the number of missing teeth, position (maxillary or mandibular), cantilever or non-cantilever and gender on the survival rate of the restorations.Results:The overall survival time for the 93 RBFPD was 13.7 years (95% CI: 12.3-15.1 years). There was a decreasing trend in complete survival and functional survival for all three material RBFPD from year to year, but complete and functional survival rates exceeded 90% at year 5 and exceeded 80% at year 10. The complete survival rate of the glass-ceramic RBFPD was higher than the other two during the follow-up period, with a complete survival rate of 90% (35/39) at year 15. The porcelain-fused-to-metal RBFPD had a higher functional survival rate in years 1-8, but the complete and functional survival rates showed a substantial decrease after year 9. The single-factor Log-rank analysis showed that the success rate of porcelain-fused-to-metal RBFPD was significantly higher than that of glass fiber reinforced RBFPD (χ2=7.33, P=0.007), and the success rate of RBFPD with 1 missing tooth restored was significantly higher than that of RBFPD with 2 missing teeth restored (χ2=3.23, P=0.072). The differences in success rates between different restoration positions (maxillary and mandibular), cantilever or non-cantilever, and gender factors were not statistically significant (χ2=2.26, P=0.133; χ2=0.68, P=0.411; χ2=1.07, P=0.300). Conclusions:For the restoration of individual missing anterior teeth, both porcelain-fused-to-metal RBFPD and glass-based ceramic RBFPD achieve a high long-term clinical success rate, with glass-based ceramic RBFPD being more able to ensure long-term restorative result.

Objective One of the major challenges to emergency department is to provide high quality and time sensitive service under limitation of human/material resources,along with patients population with extremely complex conditions.We presented a study that based on a big data got from real world and used wavelet transform technique to analyze time-dependent diseases spectrum patterns and evolution patterns,which will provide solid methodological support for optimizing resources configuration for acute care surgery service.Methods Record data of patients admitted to acute care surgery from 2007-2014 were collected by using data management tool (Avaintec,Helsinki,Finland).The data were cleansed and were transformed to continuing spectrum according to time series of admission time points (per 9 hours).Matlab was used for wavelet transform,and applied five levels of wavelet decomposition and calculated the best decomposition levels by K-mean algorithm for each level.Then we used aprori algorithm for data mining (frequent patterns mining).Results A total of 23 795 cases were enrolled and acute abdomens were made up biggest proportion of admission.Meanwhile,it is found that the spectrum of acute care surgery admission frequency was a complex rising sequence.After wavelet decomposition,signal wave A reflexed trends evolution in a given time scale,and noise wave D reflexed minutia at relevant time scale.In another words,a principal wave A1 represented fluctuation at a cycle of 16 days.Noise wave D1 reflected intensity level in this 16 days' cycle.For example,the 5 · 12 episodes of massive earthquake in 2008 were included in the study,it is found that a significant noise wave at D3 level that indicated a 4 days' cycle.Clinically,it indicated explosive admissions to acute care surgery in 4 days.Conclusions The admission spectrum to acute care surgery is a phenomenon of multi-scale.Based on wavelet decomposing,we can easily analyze the rule of admission spectrum from electronic records of patients and can be used for optimization the emergency medicine resources.

Objective To observe the inhibitory effect of pyridoxine hydrochloride (PN) combined with common chemotherapeutics on mice hepatoma cells H22 in vitro. Methods MTT assay was used to determine the effects of PN in combination with 10 different antineoplastic agents on H22 cells, and immuno-histochemistry was used to observe the distribution of PN in H22 cells and morphologic changes of the cells before and after PN treatment. Results After 24 hours incubation with 5 mmol/L PN, the treated cells expanded apparently with nucleus chipping. PN entered the tumor cell and was mainly condensed in cytoplasma and H22 cells were sensitive to PN. When administered concomitantly with chemotherapic agents, most of the combinations showed antagonistic effects while a few of the combinations were additive. For instance, doxorubicin (ADM) used in combination with PN inhibited cell proliferation with an IR value (IR=0.63) much lower than ADM alone (IR=0.71, P<0.01), and the CI value was less than 0.9, which indicated an antagonistic effect. However, PN in combination with ifosfamide (ICTX) showed additive effect (CI>0.9), and the IR value (IR=0.60) in combined group was higher than that (IR=0.40) in ICTX group (P<0.05). Conclusion PN treatment could increase the intracellular PLP level and result in growth inhibition and cell death, and combined administration of PN and ICTX might be a potential method to improve efficacy and to reduce toxic effects while a co-administration of PN and ADM should be avoided.

Aim To explore the changes of Apelin/APJ system in LPS-induced injury of rat pulmonary mi-crovascular endothelial cells( PMVECs) , and the effect and mechanism of Apelin. Methods PMVECs were cultured with the explant technique, and the identifica-tion of rat PMVECs was carried out by immunocyto-chemical staining of factorⅧrelated antigen. MTT as-say was used to evaluate the viability of PMVECs. The mRNA expression of Apelin and APJ was detected by RT-PCR. The protein expression of PCNA and the phosphorylation of Akt was analyzed by Western blot. Results The mRNA expression of Apelin and APJ showed a compensatory increase after LPS treatment for a short period of time ( P<0. 01 ) , but with the exten-sion of time, which was significantly inhibited, even lower than the control group ( P<0. 05 or P<0. 01 ) , suggesting that Apelin/ APJ system might be involved in LPS-induced PMVECs injury. MTT results showed that 10 -6 ~10 -9 mol · L-1 Apelin obviously promoted the proliferation of rat PMVECs ( P <0. 05 or P <0. 01 ) , and with certain concentration and time de-pendence. Moreover, Apelin also improved the LPS-induced PMVECs injury in different degrees ( P<0. 05 or P < 0. 01 ) . In addition, Western blot analysis showed that Apelin significantly reversed the decrease of the protein expression of PCNA and the Akt phos-phorylation level induced by LPS ( P <0. 05 or P <0. 01 ) . Conclusions The Apelin/APJ system is in-volved in LPS-induced PMVECs injury. Apelin plays an important role in protecting the pulmonary microvas-cular endothelial function and reversing the LPS-in-duced PMVECs injury, which might be related to the activation of Akt phosphorylation pathway.