北京大学学报（医学版）最新文献

{"title":"[Deep learning algorithms for intelligent construction of a three-dimensional maxillofacial symmetry reference plane].","authors":"Yujia Zhu, Hua Shen, Aonan Wen, Zixiang Gao, Qingzhao Qin, Shenyao Shan, Wenbo Li, Xiangling Fu, Yijiao Zhao, Yong Wang","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>To develop an original-mirror alignment associated deep learning algorithm for intelligent registration of three-dimensional maxillofacial point cloud data, by utilizing a dynamic graph-based registration network model (maxillofacial dynamic graph registration network, MDGR-Net), and to provide a valuable reference for digital design and analysis in clinical dental applications.</p><p><strong>Methods: </strong>Four hundred clinical patients without significant deformities were recruited from Peking University School of Stomatology from October 2018 to October 2022. Through data augmentation, a total of 2 000 three-dimensional maxillofacial datasets were generated for training and testing the MDGR-Net algorithm. These were divided into a training set (1 400 cases), a validation set (200 cases), and an internal test set (200 cases). The MDGR-Net model constructed feature vectors for key points in both original and mirror point clouds (X, Y), established correspondences between key points in the X and Y point clouds based on these feature vectors, and calculated rotation and translation matrices using singular value decomposition (SVD). Utilizing the MDGR-Net model, intelligent registration of the original and mirror point clouds were achieved, resulting in a combined point cloud. The principal component analysis (PCA) algorithm was applied to this combined point cloud to obtain the symmetry reference plane associated with the MDGR-Net methodology. Model evaluation for the translation and rotation matrices on the test set was performed using the coefficient of determination (<i>R</i>²). Angle error evaluations for the three-dimensional maxillofacial symmetry reference planes were constructed using the MDGR-Net-associated method and the \"ground truth\" iterative closest point (ICP)-associated method were conducted on 200 cases in the internal test set and 40 cases in an external test set.</p><p><strong>Results: </strong>Based on testing with the three-dimensional maxillofacial data from the 200-case internal test set, the MDGR-Net model achieved an <i>R</i>² value of 0.91 for the rotation matrix and 0.98 for the translation matrix. The average angle error on the internal and external test sets were 0.84°±0.55° and 0.58°±0.43°, respectively. The construction of the three-dimensional maxillofacial symmetry reference plane for 40 clinical cases took only 3 seconds, with the model performing optimally in the patients with skeletal Class Ⅲ malocclusion, high angle cases, and Angle Class Ⅲ orthodontic patients.</p><p><strong>Conclusion: </strong>This study proposed the MDGR-Net association method based on intelligent point cloud registration as a novel solution for constructing three-dimensional maxillofacial symmetry reference planes in clinical dental applications, which can significantly enhance diagnostic and therapeutic efficiency and outcomes, while reduce expert dependence.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"113-120"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759812/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Hydrodynamic finite element analysis of biological scaffolds with different pore sizes for cell growth and osteogenic differentiation].","authors":"Yibo Hu, Weijia Lyu, Wei Xia, Yihong Liu","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>The triply periodic minimal surface (TPMS) Gyroid porous scaffolds were built with identical porosity while varying pore sizes were used by fluid mechanics finite element analysis (FEA) to simulate the <i>in vivo</i> microenvironment. The effects of scaffolds with different pore sizes on cell adhesion, proliferation, and osteogenic differentiation were evaluated through calculating fluid velocity, wall shear stress, and permeability in the scaffolds.</p><p><strong>Methods: </strong>Three types of gyroid porous scaffolds, with pore sizes of 400, 600 and 800 μm, were established by nTopology software. Each scaffold had dimensions of 10 mm × 10 mm × 10 mm and isotropic internal structures. The models were imported to the ANSYS 2022R1 software, and meshed into over 3 million unstructured tetrahedral elements. Boun- dary conditions were set with inlet flow velocities of 0.01, 0.1, and 1 mm/s, and outlet pressure of 0 Pa. Pressure, velocity, and wall shear stress were calculated as fluid flowed through the scaffolds using the Navier-Stokes equations. At the same time, permeability was determined based on Darcy' s law. The compressive strength of scaffolds with different pore sizes was evaluated by ANSYS 2022R1 Static structural analysis.</p><p><strong>Results: </strong>A linear relationship was observed between the wall shear stress and fluid velocity at inlet flow rates of 0.01, 0.1 and 1 mm/s, with increasing velocity leading to higher wall shear stress. At the flow velocity of 0.1 mm/s, the initial pressures of scaffolds with pore sizes of 400, 600 and 800 μm were 0.272, 0.083 and 0.079 Pa, respectively. The fluid pressures were gradually decreased across the scaffolds. The average flow velocities were 0.093, 0.078 and 0.070 mm/s, the average wall shear stresses 2.955, 1.343 and 1.706 mPa, permeabilities values 0.54×10^-8 1.80×10^-8 and 1.89×10^-8 m² in the scaffolds with pore sizes of 400, 600 and 800 μm. The scaffold surface area proportions according with optimal wall shear stress range for cell growth and osteogenic differentiation were calcula-ted, which was highest in the 600 μm scaffold (27.65%), followed by the 800 μm scaffold (17.30%) and the 400 μm scaffold (1.95%). The compressive strengths of the scaffolds were 23, 26 and 34 MPa for the 400, 600 and 800 μm pore sizes.</p><p><strong>Conclusion: </strong>The uniform stress distributions appeared in all gyroid scaffold types under compressive stress. The permeabilities of scaffolds with pore sizes of 600 and 800 μm were significantly higher than the 400 μm. The average wall shear stress in the scaffold of 600 μm was the lowest, and the scaffold surface area proportion for cell growth and osteogenic differentiation the largest, indicating that it might be the most favorable design for supporting these cellular activities.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"97-105"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759801/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Clinical features and risk factors of patients with oral bleeding in dental emergency].","authors":"Huaqiu Guo, Zhe Wang, Xue Yang, Jie Bai","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>To analyze the clinical characteristics and risk factors of patients with oral bleeding.</p><p><strong>Methods: </strong>A retrospective study was performed on patients with oral bleeding in the Department of Oral Emergency in Peking University School and Hospital of Stomatology from January 2019 to December 2022. The distribution of the patients ' gender, age, cause of bleeding, systemic condition, treatment methods and risk factors of hemostasis methods, and number of visits were analyzed.</p><p><strong>Results: </strong>A total of 4 764 patients with oral bleeding were enrolled, including 2 660 males (55.84%) and 2 104 females (44.16%), with an average age of 40.7 years. The most common causes of oral bleeding were bleeding after tooth extraction (3 080 cases, 64.65%), followed by gingival bleeding (1 386 cases, 29.09%), bleeding after outpatient surgery (194 cases, 4.07%), maxillofacial mass bleeding (33 cases, 0.69%), postoperative bleeding of inpatient (24 cases, 0.50%), and bleeding from other causes (47 cases, 0.99%). Simple hemostatic methods were applied in 1 867 cases (39.19%) while 2 897 cases (60.81%) used complex methods, among which iodine strip tamponade and suture were the most commonly used methods of hemostasis. Logistic regression analysis showed that the male patients had a higher proportion of complex methods than the female patients; gingival bleeding were often stopped by simple hemostatic methods while complex methods were more likely to be applied in the patients with bleeding after tooth extraction. The patients with hypertension and coagulation disorders were more likely to visit the hospital for repeated bleeding. Gender and age did not affect the number of visits.</p><p><strong>Conclusion: </strong>Oral bleeding was one of the common diseases in oral emergency. The common causes were bleeding after tooth extraction and gingival bleeding. Most patients could be treated by compression, local suture and packing of iodine strips while some cases with severe bleeding needed further treatment to stop bleeding. A minority of patients with oral bleeding could induce systemic complications, which should be paid full attention by clinicians.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"142-147"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759785/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Bacterial biofilm formation of peritoneal dialysis catheter in patients with peritonitis-associated catheter removal].","authors":"Aichun Liu, Huiping Zhao, Bei Wu, Shuying Zheng, Li Zuo, Mei Wang","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>Peritoneal dialysis(PD)-associated peritonitis is a common and major complication of PD and the most common cause of technical failure of PD. The presence of bacterial biofilm may be an important factor leading to refractory or recurrence of peritonitis. To investigate the formation and characteristics of bacterial biofilms on PD catheters after peritonitis-associated catheter removal.</p><p><strong>Methods: </strong>The patients with maintenance PD who were regularly followed up in the Peking University People' s Hospital from June 2007 to January 2022 were retrospectively analyzed. The patients who withdrew from PD because of peritonitis and removed the PD catheter in our hospital and underwent the scanning electron microscope examination of the catheter were selected. The general information of the patients, the electron microscope results of the PD catheter and the bacterial culture results of the PD fluid were summarized.</p><p><strong>Results: </strong>(1) A total of 18 patients were included, 11 were female (accounting for 61.1%). The average age of the patients was (59.1±11.5) years, and the average duration of dialysis was (80.1±47.4) months. Primary kidney diseases were predominantly chronic glomerulonephritis (55.6%), followed by diabetic nephropathy (27.8%), and others (16.6%). The reasons for catheters removal in 18 patients were refractory peritonitis in 11 cases, recurrent peritonitis in 5 cases, and fungal peritonitis in 2 cases. (2) 16 of the 18 patients (88.9%) had catheter bacterial biofilm, and the bacterial biofilm forms were all cocci. Some were arranged in grape-like shapes, and their diameters ranged from about 500 nm to 1 000 nm. The bacterial culture results of peritoneal dialysis fluid showed that the three most common pathogens were <i>Escherichia coli</i>, methicillin-sensitive <i>Staphylococcus aureus</i> (MSSA), and <i>Staphylococcus epidermidis</i>. (3) Among the 18 patients enrolled, 13 patients (72.2%) had peritonitis in the past. The causative bacteria of peritonitis in 9 patients were cocci, including coagulase-negative <i>Staphylococci</i> (<i>Staphylococcus suis</i>, <i>Staphylococcus surface</i>, <i>Staphylococcus xylosus</i>, <i>Staphylococcus warneri</i>), <i>Staphylococcus aureus</i>, <i>Streptococcus</i> (<i>Streptococcus salivarius</i> and <i>Aerococus viridans</i>).</p><p><strong>Conclusion: </strong>Bacterial biofilm formation on the inner surface of PD catheter is common in peritonitis-associated catheter removal patients. Not all PD catheters removed due to peritonitis have bacterial biofilms. Bacterial biofilms and peritonitis pathogens may not be consistent.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"161-165"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759799/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Cyclic fatigue resistance of nickel-titanium files made by Gold heat treatment in simulated S-shaped root canals at different temperatures].","authors":"Wenxin Chen, Xiaomei Hou","doi":"","DOIUrl":"","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Objective: &lt;/strong&gt;To compare the cyclic fatigue resistance of nickel-titanium files made by 3 new heat treatment in simulated S-shaped root canals at different temperatures.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Gold heat-treated nickel-titanium files TruNatomy (25 mm, tip size 26#/0.04) and ProTaper Gold (25 mm, tip size 25#/0.08) were selected as the experimental group, M wire technique nickel-titanium file ProTaper Next (25 mm, tip size 25#/0.06) was selected as the control group. It was speculated that the Gold technique used in TruNatomy nickel-titanium file was R phase separation technique, which included a complete intermediate R-phase, increasing its flexibility. ProTaper Gold was a CM wire nickel-titanium file and the increased phase transformation temperature by heat treatment introduced martensite at room temperature, while it underwent gold heat treatment on the surface, generating an intermediate R phase during phase transformation, providing hyperelastic. ProTaper Next used M wire technique, M wire included austenite at room temperature, where heat mechanical processing introduced hardened martensite, which was incapable of participating phase transformation. Because of the lower elastic modulus of hardened martensite than austenite, the flexibility of the file was increased. Twenty instruments of each nickel-titanium file were submitted to the cyclic fatigue test by using a simulated canal with double curvatures at room tem-perature (24 ℃) and 65 ℃, 10 instruments of each nickel-titanium file were selected at each temperature (&lt;i&gt;n&lt;/i&gt;=10). At the same temperature, the number of cyclic fatigue (NCF) and fragment length were analyzed by using One-Way analysis of variance at a significance level of &lt;i&gt;P&lt;/i&gt; &lt; 0.05. NCF and fragment length of the same nickel-titanium file at room temperature and 65 ℃ were compared by paired sample &lt;i&gt;t&lt;/i&gt; test and the significance level was α=0.05. Fractured surfaces were analyzed by using scanning electron microscope.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;In double-curved canals, all the failure of the files due to cyclic fatigue was first seen in the apical curvature before the coronal curvature. At room temperature, in the apical curvature, NCF of TruNatomy was 344.4±96.6, ProTaper Gold was 175.0±56.1, ProTaper Next was 133.3±39.7, NCF of Tru Natomy was the highest (&lt;i&gt;P&lt;/i&gt; &lt; 0.05). In the coronal curvature, NCF of TruNatomy was 618.3± 75.3, ProTaper Gold was 327.5±111.8, ProTaper Next was 376.6±67.9, NCF of TruNatomy was also the highest (&lt;i&gt;P&lt;/i&gt; &lt; 0.05). There was no significant difference among the apical and coronal fragment length of the 3 nickel-titanium files (&lt;i&gt;P&lt;/i&gt;&gt;0.05). At 65 ℃, in the apical curvature, NCF of TruNatomy was 289.6±65.8, ProTaper Gold was 187.5±75.4, ProTaper Next was 103.0±38.5, NCF of TruNatomy was the highest (&lt;i&gt;P&lt;/i&gt; &lt; 0.05). In the coronal curvature, NCF of TruNatomy was 454.2±45.4, ProTaper Gold was 268.3±31.4, ProTaper Next was 283.8±31.7, NCF of TruNatomy wa","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"136-141"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759792/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Accuracy of dynamic navigation system for immediate dental implant placement].","authors":"Hong Li, Feifei Ma, Jinlong Weng, Yang DU, Binzhang Wu, Feng Sun","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>Dynamic navigation approaches are widely employed in the context of implant placement surgery. Implant surgery can be divided into immediate and delayed surgery according to the time of implantation. This retrospective study was developed to compare the accuracy of dynamic navigation system for immediate and delayed implantations.</p><p><strong>Methods: </strong>In the study, medical records from all patients that had undergone implant surgery between August 2019 and June 2021 in the First Clinical Division of the Peking University School and Hospital of Stomatology were retrospectively reviewed. There were 97 patients [53 males and 44 females, average age (47.14±11.99) years] and 97 implants (delayed group: 51; immediate group: 46) that met with study inclusion criteria and were included. Implant placement accuracy was measured by the superposition of the planned implant position in the preoperative cone beam computed tomography (CBCT) image and the actual implant position in the postoperative CBCT image. The 3-dimensional (3D) entry deviation (3D deviation in the coronal aspect of the alveolar ridge), 3D apex deviation (3D deviation in the apical area of the implant) and angular deviation were analyzed as the main observation index when comparing these two groups. The 2-dimensional (2D) horizontal deviation of the entry point and apex point, and the deviation of entry point depth and apex point depth were the secondary observation index.</p><p><strong>Results: </strong>The overall implant restoration survival rate was 100%, and no mechanical or biological complications were reported. The implantation success rate was 100%. The 3D entry deviation, 3D apex deviation and angular deviation of all analyzed implants were (1.146±0.458) mm, (1.276±0.526) mm, 3.022°±1.566°, respectively; while in the delayed group these respective values were (1.157±0.478) mm, (1.285±0.481) mm and 2.936°±1.470° as compared with (1.134±0.440) mm, (1.265±0.780) mm, 3.117°±1.677° in the immediate group. No significant differences (<i>P</i>=0.809, <i>P</i>=0.850, <i>P</i>=0.575) in accuracy were observed when comparing these two groups.</p><p><strong>Conclusion: </strong>Dynamic computer-assisted implant surgery system promotes accurate implantation, and both the immediate and delayed implantations exhibit similar levels of accuracy under dynamic navigation system that meets the clinical demands. Dynamic navigation system is feasible for immediate implantation.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"85-90"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759790/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Frameshift mutation in <i>RELT</i> gene causes amelogenesis imperfecta].","authors":"Zhenwei Zhang, Xinran Xu, Xuejun Gao, Yanmei Dong, Hua Tian","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>To analyze <i>RELT</i> gene mutation found in a pedigree with clinical features and inheritable pattern consistent with amelogenesis imperfecta (AI) in China, and to study the relationship between its genotype and phenotype.</p><p><strong>Methods: </strong>Clinical and radiological features were recorded for the affected individuals. Peripheral venous blood samples of the patient and family members were collected for further study, and the genomic DNA was extracted to identify the pathogenic gene. Whole exome sequencing (WES) was performed to analyze the possible pathogenic genes, and Sanger sequencing was performed for validation. SIFT and PolyPhen-2 were used to predict and analyze the mutation effect. Comparison of RELT amino acids across different species were performed by using Uniprot website. In addition, the three-dimen-sional structures of the wild type and mutant proteins were predicted by Alphafold 2.</p><p><strong>Results: </strong>The proband exhibited typical hypocalcified AI, with heavy wear, soft enamel, rough and discolored surface, and partial enamel loss, while his parents didn ' t have similar manifestations. WES and Sanger sequencing results indicated that the proband carries a homozygous frameshift mutation in <i>RELT</i> gene, NM_032871.3: c.1169_1170del, and both of his parents were carriers. This mutation was predicted to be pathogenic by SIFT and PolyPhen-2. Up to now, there were 11 mutation sites in <i>RELT</i> gene were reported to be associated with AI, and all of the patients exhibited with hypocalcified AI. Compared with the wild-type RELT protein, the mutant protein p. Pro390fs35 conformation terminated prematurely, affecting the normal function of the protein.</p><p><strong>Conclusion: </strong>Through phenotype analysis, gene sequencing, and functional prediction of a Chinese family with typical amelogenesis imperfecta, this study found that <i>RELT</i> gene frameshift mutation can lead to protein dysfunction in AI patients. Further research will focus on the role and mechanism of RELT in enamel development at the molecular and animal levels, providing molecular biology evidence for the genetic counseling, prenatal diagnosis, and early prevention and treatment of AI.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"13-18"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759784/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Durability of the anti-demineralization effects of fluoride varnish on dental root surfaces: An <i>in vitro</i> study].","authors":"Hongyan Tian, Xue Cai, Xiaoyan Wang","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>To study the durability of the anti-demineralization effects of fluoride varnish after being applied to dental root surfaces.</p><p><strong>Methods: </strong>Coronal and radicular dentin samples were prepared from extracted human teeth. Duraphat^® (DP) was applied to the dentine surfaces to form a protective film. The film-dentin interfaces were observed by scanning electron microscopy (SEM) and the fluoride element was analyzed with energy dispersive spectrometer (EDS). Thus, the differences between applying DP on crowns and roots were compared. Radicular dentin samples were prepared and randomly divi-ded into four groups: (1) Blank: DP was not applied, and demineralized in acetic acid (pH 4.5) for 4 days; (2) Blank+aging: DP was not applied, the samples were put into deionized water for 14 days at room temperature, and then demineralized in acetic acid (pH 4.5) for 4 days; (3) DP: DP was applied and demineralized in acetic acid (pH 4.5) for 4 days; (4) DP+aging: DP was applied, the samples were put into deionized water for 14 days at room temperature, and then demineralized in acetic acid (pH 4.5) for 4 days. Finally, SEM observation and EDS analysis of fluoride content were performed on film-dentin interfaces to evaluate the degree of demineralization, the morphology of DP film, and the penetration of fluorine.</p><p><strong>Results: </strong>The immediate penetration depth of fluoride element from DP was deeper in the coronal dentin than that in radicular dentin. The samples in the blank and blank+aging groups demine-ralized significantly after acid etching. The DP group did not undergo demineralization, and the fluorine element penetrated to (76.00±8.94) μm below the interfaces. The structure of the protective film in the DP+aging group was damaged, but the underneath dentin did not undergo demineralization. The fluorine element still remained at a depth of (5.00±3.53) μm below the interfaces.</p><p><strong>Conclusion: </strong>DP has an anti-demineralization effect on the root surface, and this effect can still be exerted for a period of time after losing the structure of protective film. It has the ability to prevent root caries and a certain durability.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"73-77"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759796/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Early efficacy of local tranexamic acid in reducing postoperative swelling in hallux valgus surgery].","authors":"Ning Sun, Xuewen Wang, Yong Wu, Shuang Ren, Heng Li, Hui DU, Xiaofeng Gong","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>To evaluate the early efficacy of local application of tranexamic acid on the osteotomy surface during hallux valgus surgery in reducing postoperative occult blood loss and thus postoperative swelling.</p><p><strong>Methods: </strong>The data of 40 cases with hallux valgus osteotomy admitted to the Department of Foot and Ankle Surgery of Jishuitan Hospital from July 11, 2022 to October 8, 2022, including 5 males and 35 females were retrospectively analyzed. According to the inclusion and exclusion criteria, 32 cases were finally divided into 16 cases in the observation group (application of tranexamic acid) and 16 cases in the control group (no application of tranexamic acid). The observation group was paired with the control group one by one in accordance with the operation style, and the change in the anterior and posterior diameter of the first metatarsal head, the change in the circumferential diameter of the foot, the length of the first metatarsal midline and the length of the plumbline of the foot measured by postoperative CT were compared between the two groups before and after surgery, in order to evaluate the degree of swelling around the incision after the surgery. The first metatarsal midline and plumb line were measured by reference to the two auxiliary lines that intersect the soft tissue border in the sesamoid bone position to measure the rotation angle of the first metatarsal. A total of three clinicians completed the measurements of these two line segments and interobserver comparisons were performed.</p><p><strong>Results: </strong>By interobserver comparison, the consistency of the length of the midline of the first metatarsal and the plumbline measured by CT was high and could be considered a reliable measurement. After the paired <i>t</i>-test, there was no statistical difference in the amount of changes in the anteroposterior diameter of the first metatarsal before and after surgery between the observation and control groups (<i>P</i>>0.05), and the amount of changes in the circumferential diameter of the foot before and after surgery was smaller in the observation group than in the control group, which was statistically significant (<i>P</i> < 0.05); the length of the midline of the first metatarsal and the plumbline of the foot measured by CT after surgery was smaller in the observation group than in the control group, which was statistically significant (<i>P</i> < 0.05).</p><p><strong>Conclusion: </strong>Local application of tranexamic acid on the osteotomy surface during hallux valgus osteotomy can relieve postoperative swelling to some extent, which may be related to the fact that tranexamic acid reduces occult blood loss in the postoperative period.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"172-177"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759809/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Influence of emergence profile designs on the peri-implant tissue in the mandibular molar: A randomized controlled trial].","authors":"Juan Wang, Lixin Qiu, Huajie Yu","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Objective: </strong>To compare the influence of different emergence profile of implants in mandibular molar on the peri-implant soft tissue.</p><p><strong>Methods: </strong>Forty-four implants were divided into two equal groups by mucosal thickness, ≥2 mm (group A) or < 2 mm (group B), and were randomly included in the test group and the control group. In the control group, the patients were treated by a prosthesis with no transmucosal modifications (subgroups A1 and B1). In groups A1 and B1, the prostheses maintained the original emergence profile of the healing abutment. In the test group, the prostheses were designed based on a width-to-height ratio (W/H) of 1.3 ∶ 1 (subgroups A2 and B2). In group A2, the buccal transmucosal configuration design was slightly concave, and in group B2, the prostheses were designed with convex buccal transmucosal configuration. Assessments were made before delivery of the definitive restoration (T0), one month (T1) and 12 months (T2) after loading. The soft tissue and prosthesis information were obtained by intraoral scan and were converted to digital models. The digital models of different time were superimposed together. Buccal mucosal W/H, emergence angle (EA) and buccal mucosal margin recession (ΔGM) were measured.</p><p><strong>Results: </strong>One year after loading, the buccal mucosal margin recession in the test group (groups A2 and B2) was significantly lower than that in the control group (groups A1 and B1). The ΔGM in group A2 was significantly lower than that in group A1 (<i>P</i>=0.033), but in groups B1 and B2, it was not significantly different. The W/H in group A2 increased significantly one month after loading, but remained stable at one year. In the A1 group, the W/H changed little from initial to one month, but increased significantly at one year after loading. The W/H in group B2 remained stable from the beginning to one year, while in group B1, it changed little one month after loading, but increased significantly by one year.</p><p><strong>Conclusion: </strong>When the initial mucosal thickness was ≥2 mm, the slightly concave prosthesis designed based on the biological W/H significantly maintained the level of buccal mucosa. When the mucosal thickness was < 2 mm, the slightly convex prosthesis design maintained a more stable W/H over one year.</p>","PeriodicalId":8790,"journal":{"name":"北京大学学报（医学版）","volume":"57 1","pages":"65-72"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759793/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}