OBJECTIVE: To compare the biomechanical properties of personalized Y-shaped plates with horizontal plates, vertical plates, and traditional Y-shaped plates in the treatment of distal humeral intra-articular fractures through finite element analysis, and to evaluate their potential for clinical application. METHODS: The study selected a 38-year-old male volunteer and obtained a three-dimensional model of the humerus by scanning his upper limbs using a 64-slice spiral CT. Four types of fracture-internal fixation models were constructed using Mimics 19.0, Geomagic Wrap 2017, Creo 6.0, and other software: horizontal plates, vertical plates, traditional Y-shaped plate, and personalized Y-shaped plate. The models were then meshed using Hypermesh 14.0 software, and material properties and boundary conditions were defined in Abaqus 6.14 software. AnyBody 7.3 software was used to simulate elbow flexion and extension movements, calculate muscle strength, joint forces, and load torques, and compare the peak stress and maximum displacement of the four fixation methods at different motion angles (10°, 30°, 50°, 70°, 90°, 110°, 130°, 150°) during elbow flexion and extension. RESULTS: Under dynamic loading during elbow flexion and extension, the personalized Y-shaped plate exhibits significant biomechanical advantages. During elbow flexion, the peak internal fixation stress of the personalized Y-shaped plate was (28.8±0.9) MPa, which was significantly lower than that of the horizontal plates, vertical plates, and traditional Y-shaped plate ( P<0.05). During elbow extension, the peak internal fixation stress of the personalized Y-shaped plate was (18.1±1.6) MPa, which was lower than those of the other three models, with significant differences when compared with horizontal plates and vertical plates ( P<0.05). Regarding the peak humeral stress, the personalized Y-shaped plate model showed mean values of (10.9±0.8) and (13.1±1.4) MPa during elbow flexion and extension, respectively, which were significantly lower than those of the other three models ( P<0.05). Displacement analysis showed that the maximum displacement of the humerus with the personalized Y-shaped plate during elbow flexion was (2.03±0.08) mm, slightly higher than that of the horizontal plates, but significantly lower than that of the vertical plates, showing significant differences ( P<0.05). During elbow extension, the maximum displacement of the humerus with the personalized Y-shaped plate was (1.93±0.13) mm, which was lower than that of the other three models, with significant differences when compared with vertical plates and traditional Y-shaped plates ( P<0.05). Stress contour analysis showed that the stress of the personalized Y-shaped plate was primarily concentrated at the bifurcation of the Y-shaped structure. Displacement contour analysis showed that the personalized Y-shaped plate effectively controlled the displacement of the distal humerus during both flexion and extension, demonstrating excellent stability. CONCLUSION The personalized Y-shaped plate demonstrates excellent biomechanical performance in the treatment of distal humeral intra-articular fractures, with lower stress and displacement, providing more stable fixation effects.
Humans ; Male ; Adult ; Healthy Volunteers ; Finite Element Analysis ; Tomography, Spiral Computed ; Models, Anatomic ; Biomechanical Phenomena ; Humeral Fractures, Distal/surgery* ; Fracture Fixation, Internal/instrumentation* ; Bone Plates ; Computer Simulation ; Precision Medicine/methods* ; Elbow Joint/surgery* ; Elbow/surgery* ; Humerus/surgery* ; Torque ; Stress, Mechanical ; Intra-Articular Fractures/surgery* ; Prosthesis Design/methods* ; Imaging, Three-Dimensional ; Range of Motion, Articular

OBJECTIVE: To explore the application progress and clinical value of digital technologies in the surgical treatment of ankylosing spondylitis (AS). METHODS: By systematically reviewing domestic and international literature, the study summarized the specific application scenarios, operational procedures, and technical advantages of digital technologies [including preoperative three-dimensional (3D) planning, intraoperative real-time navigation, robot-assisted surgery, and 3D printing] in AS surgery, and analyzed their impact on surgical accuracy, complication rates, and clinical outcomes. RESULTS: Digital technologies significantly improve the precision and safety of AS surgery. Preoperative 3D planning enables personalized surgical protocols; intraoperative navigation systems dynamically adjusts surgical trajectories, reducing the risk of iatrogenic injury; robot-assisted surgery can minimize human errors and enhance implant positioning accuracy; 3D-printed anatomical models and guides optimize the correction of complex spinal deformities. Furthermore, the combined applications of these technologies shorten operative time, reduce intraoperative blood loss, decrease postoperative complications (e.g., infection, nerve injury), and accelerate functional recovery. CONCLUSION Through multidimensional integration and innovation, digital technologies provide a precise and minimally invasive solution for AS surgical treatment. Future research should focus on their synergy with biomaterials and intelligent algorithms to further refine surgical strategies and improve long-term prognosis.
Humans ; Spondylitis, Ankylosing/diagnostic imaging* ; Printing, Three-Dimensional ; Surgery, Computer-Assisted/methods* ; Robotic Surgical Procedures/methods* ; Imaging, Three-Dimensional ; Postoperative Complications/prevention & control* ; Digital Technology ; Models, Anatomic

OBJECTIVE: To establish digital model of Ideberg typeⅡregional glenoid fracture anatomical plate with 3D metal printing technology. METHODS: The scapular imaging data of a 34-year-old healthy male volunteer were retrospectively selected. Mimics 15.01, NX 12.0 and other software were used to design Ideberg typeⅡ regional scapular fracture guide plate system. STL data were input into a metal 3D printer to print 1∶1 scapular model and anatomical plate of scapular pelvis with guide sleeve. The fit of the plate was tested in vitro and the accuracy of the screw position was evaluated by imaging. The printing time of scapular model, design of the nail path and making time of the anatomic guided plate were recorded. RESULTS: 3D metal-printed Ideberg typeⅡ guide plate for scapular fracture fitted well to 3D printed scapular model, the locking screw was oriented accurately, and X-ray and CT showed good screw position. The printing time of scapula model, time of nail path design and special-shaped anatomical guide plate production were 52.0, 15.0 and 320 min, respectively. CONCLUSION Anatomical plates based on 3D metal printing technology could achieve good adhesion of Ideberg typeⅡ regional fractures and precise screw placement, providing a new and accurate surgical method for the treatment of Ideberg typeⅡ glenoid fractures.
Humans ; Printing, Three-Dimensional ; Male ; Adult ; Bone Plates ; Fractures, Bone/diagnostic imaging* ; Fracture Fixation, Internal/methods* ; Pelvic Bones/surgery* ; Metals ; Scapula/surgery* ; Models, Anatomic

PURPOSE: To judge the injury mode and injury severity of the real human body through the measured values of anthropomorphic test devices (ATD) injury indices, the mapping relationship of lumbar injury between ATD and human body model (HBM) was explored. METHODS: Through the ATD model and HBM simulation, the mapping relationship of lumbar injury between the 2 subjects was explored. The sled environment consisted of a semi-rigid seat with an adjustable seatback angle and a 3-point seat belt system with a seatback-mounted D-ring. Three seatback recline states of 25°, 45°, and 65° were designed, and the seat pan angle was maintained at 15°. A 23 g, 47 km/h pulse was used. The validity of the finite element model of the sled was verified by the comparison of ATD simulation and test results. ATD model was the test device for human occupant restraint for autonomous vehicles (THOR-AV) dummy model and HBM was the total human model for safety (THUMS) v6.1. The posture of the 2 models was adjusted to adapt to the 3 seat states. The lumbar response of THOR-AV and the mechanical and biomechanical data on L1 - L5 vertebrae of THUMS were output, and the response relationship between THOR-AV and THUMS was descriptive statistically analyzed. RESULTS: Both THOR-AV and THUMS were submarined in the 65° seatback angle case. With the change of seatback angle, the lumbar spine axial compression force (F_z) of THOR-AV and THUMS changed in the similar trend. The maximum F_z ratio of THOR-AV to THUMS at 25° and 45° seatback angle cases were 1.6 and 1.7. The flexion moment (M_y) and the time when the maximum M_y occurred in the 2 subjects were very different. In particular, the form of moment experienced by the L1 - L5 vertebrae of THUMS also changed. The changing trend of M_y measured by THOR-AV over time can reflect the changing trend of maximum stress of L1 and L2 of THUMS. CONCLUSION The F_z of ATD and HBM presents a certain proportional relationship, and there is a mapping relationship between the 2 subjects on F_z. The mapping function can be further clarified by applying more pulses and adopting more seatback angles. It is difficult to map M_y directly because they are very different in ATD and HBM. The M_y of ATD and stress of HBM lumbar showed a similar change trend over time, and there may be a hidden mapping relationship.
Humans ; Lumbar Vertebrae/injuries* ; Finite Element Analysis ; Biomechanical Phenomena ; Manikins ; Spinal Injuries/physiopathology*

Pulpitis is a common infective oral disease in clinical situations. The regulatory mechanisms of immune defense in pulpitis are still being investigated. Osteomodulin (OMD) is a small leucine-rich proteoglycan family member distributed in bones and teeth. It is a bioactive protein that promotes osteogenesis and suppresses the apoptosis of human dental pulp stem cells (hDPSCs). In this study, the role of OMD in pulpitis and the OMD-induced regulatory mechanism were investigated. The OMD expression in normal and inflamed human pulp tissues was detected via immunofluorescence staining. Intriguingly, the OMD expression decreased in the inflammatory infiltration area of pulpitis specimens. The cellular experiments demonstrated that recombined human OMD could resist the detrimental effects of lipopolysaccharide (LPS)-induced inflammation. A conditional Omd knockout mouse model with pulpal inflammation was established. LPS-induced inflammatory impairment significantly increased in conditional Omd knockout mice, whereas OMD administration exhibited a protective effect against pulpitis. Mechanistically, the transcriptome alterations of OMD overexpression showed significant enrichment in the nuclear factor-κB (NF-κB) signaling pathway. Interleukin-1 receptor 1 (IL1R1), a vital membrane receptor activating the NF-κB pathway, was significantly downregulated in OMD-overexpressing hDPSCs. Additionally, the interaction between OMD and IL1R1 was verified using co-immunoprecipitation and molecular docking. In vivo, excessive pulpal inflammation in Omd-deficient mice was rescued using an IL1R antagonist. Overall, OMD played a protective role in the inflammatory response via the IL1R1/NF-κB signaling pathway. OMD may optimize the immunomodulatory functions of hDPSCs and can be used for regenerative endodontics.
Pulpitis/metabolism* ; NF-kappa B/metabolism* ; Animals ; Signal Transduction ; Humans ; Mice ; Mice, Knockout ; Dental Pulp/metabolism* ; Disease Models, Animal ; Lipopolysaccharides

Tooth pulpitis is a prevalent oral disorder. Understanding the underlying mechanisms of pulpitis and developing effective treatment strategies hold great significance. Ferroptosis has recently emerged as a new form of cell death, but the role of ferroptosis in pulpitis remains largely unknown. In our study, single-cell RNA sequencing (scRNA-seq) was used to identify cellular heterogeneity between 3 pulpitis tissue and 3 healthy pulp tissue, and explored ferroptosis occurrence in pulpitis tissue and inflamed dental pulp cells (DPCs). In scRNA-seq, 40 231 cells (Pulpitis: 17 814; Healthy pulp: 22 417) were captured, and visualized into 12 distinct cell clusters. Differentially expressed ferroptosis-related genes (DE-FRGs) were almost presented in each cluster in pulpitis vs healthy pulp. ROS and Fe²⁺ levels significantly rose, and immunohistochemistry showed low expression of GPX4 and high expression of PTGS2 in pulpitis. In LPS-stimulated DPCs, thymosin α1 increased the expression of GPX4 and FTL, and decreased expression of TNF-α, IL-1β, IL-6, and Fe²⁺ levels. In rat pulpitis models, both prothymosin α (PTMA, precursor of thymosin α1) gelatin sponge placed at the hole of pulp (LPS-P(gs)) and PTMA injection in pulp (LPS-P(i)) significantly reduced infiltration of inflammatory cells and expression of PTGS2, and increased the expression of GPX4. In RNA sequencing, the expression of DE-FRGs were reversed when thymosin α1 were added in LPS-stimulated DPCs. Collectively, single-cell atlas reveals cellular heterogeneity between pulpitis and healthy pulp, and ferroptosis occurrence in pulpitis. Thymosin α1 may reduce ferroptosis in DPCs to alleviate pulpitis and thus potentially has the ability to treat pulpitis.
Ferroptosis/drug effects* ; Dental Pulp/drug effects* ; Animals ; Pulpitis/pathology* ; Rats ; Thymalfasin/pharmacology* ; Humans ; Male ; Thymosin/pharmacology* ; Disease Models, Animal ; Rats, Sprague-Dawley

OBJECTIVES: This study aimed to investigate the influence of the dimensional stability of 3D printed resin master model on the replication accuracy of implant replicas. METHODS: Ten digital impressions of patients undergoing continuous crowns or fixed bridge restoration supported by two implants were obtained, and resin models with implant replicas were 3D printed. Scanning rods were fixed on the replicas 3, 7, and 14 days after printing. The 3D, linear, and angular deviations of the scanning rods at different times were analyzed through Geomagic Wrap 2021 software. RESULTS: The position of the replicas shifted mesiolingually, in the same direction as the shrinkage of the model. From day 7 onward, the 3D, distance linear, and angular deviations of the replicas (scanning rod) significantly increased compared with those on the 3rd day (P<0.05). On the 14th day, the changes were even more pronounced, with the above deviations showing statistical significance (P<0.05) compared with those for the 3-day and 7-day groups. No statistical difference in height linear deviation was observed among the groups. CONCLUSIONS The insufficient dimensional stability of 3D printed resin models can lead to changes in the relative position and angle of the replicas, thereby affecting the accuracy of the replicas in recreating the implant's position. Complete manufacturing of prosthesis is recommended within 7 days after the model is printed.
Printing, Three-Dimensional ; Humans ; Dental Implants ; Models, Dental ; Dental Impression Technique ; Crowns

OBJECTIVES: To evaluate the accuracy of a self-developed extraoral scanning system based on four-camera stereophotogrammetric technology in the acquisition of three-dimensional positional information on dental implants and conduct a comparative study involving an intraoral scanning system. METHODS: With the use of an in vitro edentulous jaw model with implants, extraoral (experimental group) and intraoral (control group) scanning systems were employed to obtain STL (Standard Tessellation Language) datasets containing three-dimensional morphological and positional information on scan bodies. In addition, a dental model scanner was used to obtain reference data. The three-dimensional morphological, linear, and angular deviations between groups and reference data were analyzed using Geomagic Wrap 2021 software to compare trueness and precision. RESULTS: The extraoral scanning system demonstrated superior trueness in three-dimensional morphological, linear, and angular deviations compared with the intraoral scanning system, with statistically significant differences (P<0.001). The extraoral scanning system also showed a higher precision in three-dimensional morphological deviation (P<0.001). As the number of implants increased, the extraoral scanning system exhibited increased three-dimensional morphological and linear deviations (P<0.001) but maintained a stable angular deviation. The intraoral scanning system displayed significant increases in three-dimensional morphological, linear, and angular deviations with the increase in the number of implants (P<0.05). CONCLUSIONS The stereophotogrammetry-based extraoral scanning system outperforms intraoral scanning system in terms of the accuracy for multi-unit implant positioning and provides a novel approach for attaining a fully digital workflow for implant rehabilitation in edentulous jaws.
Jaw, Edentulous ; Humans ; Dental Impression Technique ; Dental Implants ; Imaging, Three-Dimensional/methods* ; Photogrammetry/methods* ; Models, Dental

OBJECTIVES: This study aimed to use machine learning algorithms to build a prediction model of the first permanent molar caries of 9-year-old children in Suzhou and screen out risk factors. METHODS: Random stratified whole group sampling was applied to randomly select 9-year-old students from 38 primary schools in 14 townships and streets in Wuzhong District for oral examination and questionnaire survey. Multifactor Logistics regression was used to analyze the risk factors of tooth decay. The data set was randomly divided into training sets and verification sets according to 8∶2, and R 4.3.1 was used to build five machine learning algorithms: random forest, decision tree, extreme gradient boosting (XGBoost), Logistics regression, and lightweight gradient enhancement (LightGBM). The predictive effect of these five models was evaluated using the area under the characteristic curve (AUC). The marginal contribution of quantitative characteristics to the caries prediction model was determined through Shapley additive explanations (SHAP). RESULTS: This study included 7 225 samples that met the standard. The caries rate of the first permanent molar was 54.96%. Multifactor Logistic regression analysis showed that sweet drinks, dessert and candy, snack frequency, and snacks before going to bed after brushing teeth were correlated with the occurrence of first permanent molar caries (P<0.05). The AUC values of decision tree, Logistic regression, LightGBM, random forest, and XGBoost were 75.5%, 83.9%, 88.6%, 88.9%, and 90.1%, respectively. Compared with the variables after single heat coding, the SHAP value of high-frequency sweets (such as dessert candy ≥2 times a day, mother's sugary diet ≥2 times a day) and bad oral hygiene habits (such as frequent snacks before going to bed after brushing teeth and irregular brushing teeth) exhibited the highest positive. CONCLUSIONS XGBoost algorithm has a good prediction effect for first permanent molar caries in 9-year-old children. High-frequency sweet factors and bad oral hygiene habits have a strong positive impact on the risk of first permanent molar caries and are key drivers that can be used in the formulation of targeted interventions.
Humans ; Dental Caries/epidemiology* ; Child ; Machine Learning ; China/epidemiology* ; Molar ; Risk Factors ; Female ; Logistic Models ; Male ; Decision Trees ; Algorithms

Decontamination ; Disinfection ; Manikins ; Protective Clothing ; Personal Protective Equipment ; Health Personnel