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Objective In view of the situation that tracheal atrophy causes the overall airway size to become smaller in the elderly, effects of the airway wall surface on reconstruction of a narrow airway and the airflow field under different respiratory conditions were investigated. Methods A three-dimensional (3D) model of human airway was established by using Mimics, and flow field in the airway was simulated by computational fluid dynamics (CFD) method. The inner wall pressure and the distribution of airflow were analyzed and compared under different breathing states. Results Under different respiratory states, the pressure of endotracheal wall was relatively uniform in the endotracheal wall, but decreased significantly in air inlet of the bronchial stenosis segment, and reached negative pressure near the narrowest area. The airflow velocity decreased from the center of the pipe to the boundary layer, and the velocity reached the maximum at the narrow area. Vortex was generated when airflow passed through the narrow area, and the larger the inlet flow velocity was, the larger the positive pressure and negative pressure were, the more obvious the pressure drop at the narrow area was, and the more obvious the vortex phenomenon was. Conclusions The constriction of the airway stenosis area caused by negative pressure will lead to the patient’s dyspnea, and the eddy current will cause the airway wall to be affected by the aerodynamic shear stress and may damage the airway wall mucosa. Therefore, understanding of the pressure distribution and velocity distribution in the narrow airway can provide references for clinical diagnosis and treatment of such diseased airways.
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In this study, the reverse engineering technology was used to analyze the prescription and process of Doppelherz® Energy DIRECT, based on the composition of the prescription on the official website of the product, the detection method of composition is established according to the pharmacopoeia and literature information, combined with gravimetric analysis to complete prescription analysis. The prescription composition of the reference listed drug was determined to be composed of caffeine, taurine, vitamin B, anhydrous glucose, citric acid, sorbitol, sucralose, magnesium salts of fatty acids, in which the glucose content was 71.4%, the citric acid content was 7.0% and the magnesium salts of fatty acids content was < 5.8%. According to patent inquiry, Raman imaging and other technologies, the preparation process of the marketed preparation has been basically obtained, and the development of the self-made preparation has been completed on this basis. The study was approved by the Ethics Committee of the Academy of Military Medical Sciences. Combined with the results of the taste evaluation experiment and the caffeine dissolution test of the preparation in 1 min, the hot-melt extrusion technology was screened out as the taste-masking technology of the self-made preparation, the parameters of the hot-melt extrusion process were screened by differential scanning calorimetry analysis, and finally a product with good taste and qualified quality was obtained, which provided a reference method for the research and development of related preparations.
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Objective The three-dimensional (3D) solid model of medulla oblongata-upper cervical spinal cord based on specimen pathological section data was established, and the stress and strain levels of medulla oblongata-upper cervical spinal cord under dentate process compression were obtained by finite element analysis, so as to provide references for clinical research. Methods Mimics was used to process the slice data, so as to establish the point cloud model. SolidWorks was used to locate, edit and optimize the point cloud model, so as to establish the 3D solid model. HyperMesh was used to establish the finite element model and ANSYS was used for finite element analysis. Results The medulla oblongata-upper cervical spinal cord model with clear boundary between gray matter and white matter and white matter fiber bundle was established. The stress and strain levels and stress-strain curves of white matter and gray matter under different compression degrees were obtained. Conclusions Combined with pathological sections of specimens and reverse engineering, the 3D medulla oblongata-upper cervical spinal cord model with clear morphology and structure of gray/white matter can be established. When the medulla oblongata-upper cervical spinal cord is compressed, the stress level of gray matter is lower than that of white matter, and about 20% of compression is the critical state of white matter. When the disease develops beyond the critical state, the biomechanical properties of white matter may fail, resulting in gray matter damage.
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BACKGROUND: Biomechanical properties of the residual limb-socket interface not only have a direct impact on the fit of the prosthesis, but also the basis for optimal design of the socket structure. Combining digital design technology with rehabilitation medical engineering will effectively improve the efficiency and quality of the prosthesis socket. OBJECTIVE; The reverse-positive combined modeling method was used to design a custom-made socket model for patients with calf amputation to evaluate the interfaciai stress between the residual limb and the socket. The socket was iteratively designed. The optimized model was produced by three-dimensional printing to improve traditional hand-made socket methods. METHODS: Two patients with calf amputation were selected (Volunteers of the Inner Mongolia Honorary Military Rehabilitation Center). According to the CT scan image of the patient’s residual limb, Mimics was used for image processing, and then Geomagic and UG were used to obtain the geometric model of the residual limb. Through the use of the computer-aided design software Fusion360, the socket was forward modeled according to the different tolerances of the tissue structure of the various parts of the residual limb. The Mooney-Revlin superelastic model was used to define the material properties of the soft tissue, and the finite element analysis of the residual limb-socket interface stress was performed. The iterative design of the socket was carried out according to the feedback of the results, and the acceptance socket model after re-modification was evaluated. Three-dimensional printing produced a socket, which received experimental measurements. RESULTS AND CONCLUSION: (1) The stress of the interface between the socket and the residual limb after iterative design was analyzed, and the stress values of the residual limbs were lower than the pain threshold, which met the design standard and could achieve functional transferability and safety comfort. (2) Two patients wearing three-dimensional printing made the socket adaptability and stability, and the walking symmetry was significantly improved compared with the hand-made socket, meeting the biomechanical requirements of the residual limb. (3) A complete design, evaluation and manufacturing system for the prosthetic lumen was established.
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Objective: The reverse engineering technology was used to analyze the prescription and process of Good Sense Stay Awake®, the reference listed drug of caffeine tablets, in order to provide guidance for the development of generic caffeine tablets. Methods: Firstly, the prescription information of the reference listed drug was obtained by literature research. Then, quantitative analysis of the composition of the prescription was achieved by the high-performance liquid chromatography with a crystal refractive index detection and the gravimetric analysis method;the particle size of raw and auxiliary materials was analyzed by Raman imaging technology;the crystal habit and crystal form of active pharmaceutical ingredient(API)were characterized by the optical microscope and X-ray powder diffraction technology, respectively;the preparation process of reference listed drug was determined by disintegration method;and finally, the package material was identified by the morpholine reagent. Moreover, three batches of samples were pre-pared according to the determined prescription and process, and the quality was compared with the reference listed drug. Results: By the reverse engineering analysis of the reference listed drug, the prescription composition of the reference listed drug was determined to be composed of glucose, microcrystalline cellulose, pregelatinized starch, maltodextrin, magnesium stearate, colloidal silica and yellow lake, in which the glucose content was 32% and the microcrystalline cellulose content was <23%. The API crystal form of the reference listed drug was consistent with that of the self-made preparation. The average particle size of caffeine, microcrystalline cellulose, glucose, maltodextrin and pregelatinized starch was approximately 206, 112, 172 and 61 μm, respectively. The tablet preparation process was the direct compression method, and the packaging material was polyvinyl chloride aluminum foil. The quality of the three batches of home-made preparations was the same as that of the reference listed drug. Conclusion: Caffeine tablets with the same quality as Good Sense Stay Awake® were successfully prepared by reverse engineering of the reference listed drug, which provides a reference for the application of reverse engineering in the generic drug development and consistency evaluation.
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Objective@#To analyze the impact of the activation mode on the results of space closure in the mandibular arch using a double keyhole loop (DKHL) with a typodont model and reverse engineering technique to provide guidance for clinical treatment. @*Methods@#Nine normal mandibular typodont models after leveling were randomly divided into 3 groups, which then underwent three types of DKHL activation for space closure. Each model was assessed at the initial stage and after the warm water bath, and the images were superimposed to measure the displacement of special crown and root mark points. All statistical analysis of the data was performed using SPSS 19.0@*Results@# After equal activation times, the root retraction of anterior teeth and the crown forward position of posterior teeth in groups activated at the distal loop (conditions 2 and 3) were much greater than those in the group activated horizontally (condition 1). Activation between mesial and distal loops (condition 3) induced significant anterior tooth intrusion, together with elongation and buccal inclination of posterior teeth. The displacement of mark points among the three conditions showed a statistically significant difference. @* Conclusion @# The movement of mandibular anterior and posterior teeth could be flexibly controlled through different DKHL activation modes, which should be chosen carefully according to individual conditions.
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Objective: To design osteotomy templates for the construction of mandibular defect by using fibular flap in a reverse engineering technique approach. Methods: Five patients with mandibular defect were enrolled and their treatments were designed in a three-dimensional (3D) virtual planning software package. The 3D printing model with shaped reconstruction plate and titanium-screws were under CT scanning and the image was reconstructed and registered back to the original mandible and fibula in a surface-best-fit method. Then the osteotomy template with screw holes of shaped reconstruction plate was designed and fabricated. The reconstruction of mandible with multiple fibular segments was guided by the osteotomy template. Results: All the five patients were discharged successfully with satisfied outcome. The deviation between virtual plan and actual results were calculated: max deviation (3.53±2.33) mm and the angle deviation 3.31˚±1.48˚. Conclusion: The accuracy of the osteotomy template is satisfied and can be applied to the clinical use.
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This paper aims to explore the feasibility of building a finite element model of left atrial diverticulum (LAD) using reverse engineering software based on computed tomography (CT) images. The study was based on a three-dimensional cardiac CT images of a atrial fibrillation patient with LAD. The left atrium and LAD anatomical features were accurately reproduced by using Geomagic Studio 12 and Mimics 15 reverse engineering software. In addition, one left atrial model with LAD and one without LAD were created with ANSYS finite element analysis software, and the validity of the two models were verified. The results show that it is feasible to establish the LAD finite element model based on cardiac three-dimensional CT images using reverse engineering software. The results of this paper will lay a theoretical foundation for further hemodynamic analysis of LAD.
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BACKGROUND:As lumbar spine biomechanics research is unceasingly thorough and the constant development of related fusion and dynamic fixation device, the spine fusion technique which is represented by artificial disc replacement is a new choice to the spine surgeons. Therefore, it is particularly important to design reasonable artificial intervertebral disc. OBJECTIVE:To establish the finite element model of the new artificial disc replacement of the lumbar motion segment for further biomechanical study. METHODS:The L3-4 thin-section CT images of a healthy male volunteer was selected, combined with human anatomy data and applied the reverse engineering technology to rebuild the lumbar spine model with medical image software Mimics and tool software Geomagic Studio. The three-dimensional model of the silicone artificial disc was converted into a finite element model through software ANSYS12.0. RESULTS AND CONCLUSION:Through CT scanning, digital image processing and computer-aided design, the three-dimensional model of the lumbar motion segment and the finite element model of artificial disc replacement were successful y established. The finite element model contained 691 085 units and 1 008 913 nodes which could be applied constraint and load and could be used for spinal biomechanics and the further research of the new artificial intervertebral disc.
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Objective: To explore a simple and effective method for establishing three dimensional finite element model of the maxillary first premolar, so as to provide a mathematic model for future biomechanic research. Methods: Micro-CT was used to scan the extracted, intact left maxillary first premolar and the obtained images were transferred for use. The point data of the enamel, dentin, and pulp were collected by Mimics 10.0 software and were fed into Imageware 12.0 software for treatment with point cloud data and inverse algorithm of curve. After surface fitting, the tooth solid model was accomplished by Ansys 11.0 software. Then the enamel, dentin, and pulp were integrated through Boolean operation using Ansys 11.0. The solid models of periodontium and alveolar bone were constructed and the 3D meshes were created separately; and the models were tested with loading. Results: A fine three-dimensional finite element model of the maxillary first premolar, including the pulp, periodontium and alveolar bone was established. After 3D meshing, the enamel had 26 685 tetrahedral elements, the dentin had 11 082 tetrahedral elements, the pulp had 11 843 tetrahedral elements, the periodontium had 22 004 tetrahedral elements, and the alveolar bone had 66 767 tetrahedral elements. The model had a total of 241 381 10-node-tetrahedral elements; it had a high precision and exactly demonstrated the morphology of the tooth and the curvilinear shape of enamelo-cementel junction. The stress distribution of enamel focused on the middle of occlusal face and enamelocemental junction; the stress distribution of dentin also focused on the enamelo-cemental junction. Conclusion: A three-dimensional finite element model of maxillary first premolar has been established by combining the Micro-CT technology and reverse-engineering software; the model has satisfactory geometric and mechanical comparability.
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PURPOSE: The template-guided implant surgery offers several advantages over the traditional approach. The purpose of this study was to evaluate the accuracy of coordinate synchronization procedure with 5-axis milling machine for surgical template fabrication by means of reverse engineering through universal CAD software. MATERIALS AND METHODS: The study was performed on ten edentulous models with imbedded gutta percha stoppings which were hidden under silicon gingival form. The platform for synchordination was formed on the bottom side of models and these casts were imaged in Cone beam CT. Vectors of stoppings were extracted and transferred to those of planned implant on virtual planning software. Depth of milling process was set to the level of one half of stoppings and the coordinate of the data was synchronized to the model image. Synchronization of milling coordinate was done by the conversion process for the platform for the synchordination located on the bottom of the model. The models were fixed on the synchordination plate of 5-axis milling machine and drilling was done as the planned vector and depth based on the synchronized data with twist drill of the same diameter as GP stopping. For the 3D rendering and image merging, the impression tray was set on the conbeam CT and pre- and post-CT acquiring was done with the model fixed on the impression body. The accuracy analysis was done with Solidworks (Dassault systems, Concord, USA) by measuring vector of stopping's top and bottom centers of experimental model through merging and reverse engineering the planned and post-drilling CT image. Correlations among the parameters were tested by means of Pearson correlation coefficient and calculated with SPSS (release 14.0, SPSS Inc. Chicago, USA) (alpha = 0.05). RESULTS: Due to the declination, GP remnant on upper half of stoppings was observed for every drilled bores. The deviation between planned image and drilled bore that was reverse engineered was 0.31 (0.15 - 0.42) mm at the entrance, 0.36 (0.24 - 0.51) mm at the apex, and angular deviation was 1.62 (0.54 - 2.27)degrees. There was positive correlation between the deviation at the entrance and that at the apex (Pearson Correlation Coefficient = 0.904, P = .013). CONCLUSION: The coordinate synchronization 5-axis milling procedure has adequate accuracy for the production of the guided surgical template.
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Chicago , Collodion , Cone-Beam Computed Tomography , Gutta-Percha , Mandrillus , Models, Theoretical , SiliconesABSTRACT
New surgical techniques utilizing computer-aided engineering have been recently developed to improve the quality of surgery and reduce the risk to patients. This paper reports the surgical cases using rapid prototyping assisted orthopeadic fracture surgery (RPAOFS). RPAOFS utilizes the symmetric characteristics of the human body, and the potential for RE and RP in which the physical shape is manufactured repidly from the CT data. The physical shape before the injury was manufactured from the RP using the mirror transformed CAD data of the uninjured extents. Subsequently, pre-operative planning, such as the selection of the proper implant, preforming of the implant, selection of the fixation positions, and surgery are performed utilizing the physical shape. RPAOFS was applied to two cases such as a distal tibia communited fracture and a proximal tibia plateau fracture. The surgical results showed that RPAOFS is an effective surgical tools.
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Humans , Human Body , Surgery, Computer-Assisted , TibiaABSTRACT
In this paper,RE&RP's engineering principle and basic medical application such as surgery's design are introduced.In the end there is a view of its application prospect.
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Objective To discuss the foreground of application of reverse engineering reconstruction of dental models and to establish the foundation of developing a system for complete denture CAD/CAM. Methods The models of an edentulous jaw were measured with reverse engineering, and the 3D models were reconstructed with a computer. Results 3D models of the edentulous jaw were achieved. The characteristics of these 3D images were clear and accurate. Conclusion CAD models are reconstructed with reverse engineering accurately and technical problems in 3D model of complete denture CAD/CAM are resolved.
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Objective:To establish a precise three-dimensional finite element model of temporomandibular joint.Methods: On the basis of images of Chinese Visible Human, the reverse engineering technology was applied to reconstruct the Computer Aided Design(CAD) model of temporomandibular joint.Afterwards, the model was established. Results:A three-dimensional finite element model consisting of 66 122 nodes and 212 704 elements of temporomandibular joint including cortical bone, cancellous bone, mandibular dental arch, masticatory muscles, articular cartilage and periodontal ligament was constructed. Conclusion:The finite element model is more efficient and more precise.
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Objective:To explore a method for setting up three dimensional finite element model of posterior glass fiber reinforced composite resin-bonded-fixed-partial dentures (GFRC-RBFPD) including restoration, periodontal tissue and alveolar bone. Methods:A stone model was fabricated including abutments and pontic of restoration, then it was scanned with laser scanner. Acquired data were integrated in Geomagic 5.0. Basic 3D geometric model was established. Different parts of abutement and prosthesis were designed in I-DEAS 10 NX Series and Geomagic, then periodontal tissue and alveolar bone were set up in Geomagic 5.0. Completed 3D geometric model was input into MSC.Marc Mentat 2003 for mesh generation. Boundary conditions were defined. Model was calculated in Mentat 2003. Results:3D geometric model and finite element model including GFRC-RBFPD, abutments, periodontal membrane and bone (bone lamina dura,cortical bone and cancellous bone) were established.Little contour information was lost, comparability between models was improved.Conclusion:The 3-dimensional laser scanning technique, CAD and mesh generation technique are effective in the establishment of 3-dimensional finite element model of GFRC-RBFPD.
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Objective To discuss the accuracy of 3DSS three-dimensional scanning system, which was used to reconstruct the 3D digital model of unilateral orbital defect patients. Methods By using 3DSS spectrometer on the case of patients with unilateral orbital defect, the related scan dates of facial structure were collected, and the reconstructed digital models were processed wax pattern by SLS prototyping machine. Results The digital solid model of three-dimensional reconstruction was smooth and complete, and border over the natural. The designed resin prosthesis can be inosculated with the orbital defect tightly and symmetrically. Conclusion To adopt the system can be successfully completed unilateral orbital defect restoration design and production, and ultimately satisfied the clinical requirement of prosthesis production.