2.Personalized GYROID condylar prosthesis:design and finite element analysis
Danyu LIU ; Tingting JIANG ; Zhixiu JIANG ; Yuchen JI ; Yilin CAO ; Lei WANG ; Yucheng SU ; Xinyu WANG
Chinese Journal of Tissue Engineering Research 2025;29(17):3548-3556
BACKGROUND:Currently,the mandibular joint prosthesis manufactured at home and abroad needs to rely on screws to fix the condylar part of the prosthesis during the replacement process,and the retention hole is reserved to facilitate the operation during the operation.However,due to the lack of personalized jaw design,the reattachment plate may not fit the jaw,resulting in screw loosening and dislocation.Therefore,personalized condylar prosthesis replacement is of great value in the repair of the temporomandibular joint.OBJECTIVE:To design a personalized condylar prosthesis with an internal GYROID for mandibular condylar repair and reconstruction.METHODS:The GYROID structure was selected in the Rhinoceros 7 software with the single cell size of 6 mm and the wall thickness of 0.2,0.3,0.4,0.5,0.6,0.7,0.8 mm.The mechanical properties of the GYROID structure were analyzed by finite element method.3D printing of GYROID structural test specimens with different wall thickness(0.2,0.3,0.4,0.5,0.6,0.7,and 0.8 mm)was performed to test the mechanical properties of the specimens through room temperature compression experiments.A wall thickness value conforming to the range of mandibular mechanical properties was selected through finite element analysis and room temperature compression test results.An adult male mandibular CT data were used for inverse modeling to design a condylar prosthesis with an internal GYROID.Finite element analysis was used to simulate the movement of the apical staggered position and the opposite-blade jaw position after condylar prosthesis replacement.RESULTS AND CONCLUSION:(1)The results of finite element analysis and room temperature compression experiment showed that the elastic modulus of the GYROID structure increased with the increase of wall thickness.The elastic modulus of the GYROID structure with wall thickness of 0.5-0.7 mm was within the range of the elastic modulus of the mandible(1.5-4.0 GPa).Therefore,the 6 mm monocellular GYROID structural model with a wall thickness of 0.6 mm was selected for the design of the condylar prosthesis.(2)The results of finite element analysis showed that the stress distribution of mandibular model was symmetrical.The stress distribution of the two types of occlusion was roughly the same,and the stress peak was not significantly different.The stress concentrated in the neck of the condylar prosthesis,and the stress on the replacement side was slightly larger than that on the healthy side.The maximum equivalent stress of the whole internal fixation model was 269.34 MPa,and the maximum equivalent stress of the screw was 20.14 MPa.The equivalent stress and equivalent strain values of the prosthesis were greater than that of the opposite edge jaw position when the tooth tip was interlaced.The equivalent stress and equivalent strain values of the screw were smaller than that of the opposite edge jaw position when the tooth tip was interlaced.(3)The results showed that the design and retention of the personalized GYROID condylar prosthesis were good,which was consistent with the mechanical conduction of the mandible.
3.Design of customized Gyroid condylar prosthesis and finite element analysis of articular disc
Tingting JIANG ; Danyu LIU ; Zhixiu JIANG ; Yuchen JI ; Yilin CAO ; Yucheng SU ; Xinyu WANG
Chinese Journal of Tissue Engineering Research 2025;29(28):6003-6011
BACKGROUND:Condylar prosthesis replacement,as one of the surgical methods for the treatment of temporomandibular joint diseases,not only needs to restore the morphology and function,but also needs to ensure long-term stable application.OBJECTIVE:To design finite element analysis of a customized Gyroid condylar prosthesis.METHODS:Gyroid structure specimens with different wall thicknesses(250,350,450,550,650,and 750 μm)were designed by software.Finite element simulation compression experiments were carried out to test the elastic modulus of the specimens.The Gyroid structure wall thickness range that matches the elastic modulus of mandibular cancellous bone and whose pore size meets the osteogenesis conditions was screened out.This range was subdivided and Gyroid structure specimens were made using 3D printing technology.Mechanical compression experiments were carried out on a universal testing machine.The Gyroid structure wall thickness that meets the mechanical properties of mandibular bone,has an easier osteogenesis and a smaller strength was screened out by elastic modulus and compressive strength,and subsequent experiments were carried out.A three-dimensional model of a customized Gyroid condylar prosthesis was designed,and the finite element analysis of the blade jaw position and cusp interdigitation position of the model under natural occlusion was simulated.RESULTS AND CONCLUSION:(1)Finite element analysis results showed that with the increase of wall thickness,the elastic modulus of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 350,450,550,650,and 750 μm matched the elastic modulus of mandibular cancellous bone.Since the subsequent experiments needed to be subdivided into groups and the pore size of the 550,650,and 750 μm wall thickness group(pore size 800-1 000 μm)was within the osteogenesis range.Gyroid structure specimens with wall thickness of 550,600,650,700,and 750μm were selected for mechanical compression experiments on a universal testing machine.(2)The results of mechanical compression experiments showed that with the increase of wall thickness,the elastic modulus and compressive strength of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 550,600,and 650 μm was within the elastic modulus of the mandibular cancellous bone.Finally,the wall thickness of 650 μm and the pore size of 900 μm were selected to construct the three-dimensional model of the mandibular customized Gyroid condylar prosthesis.(3)The results of finite element analysis of three-dimensional model of the mandibular customized Gyroid condylar prosthesis showed that the stress of the articular disc in the edge-to-edge occlusion was mainly concentrated on the lower surface of the anterior middle band,and the stress of the articular disc in the interposition of tooth tips was mainly concentrated on the lateral surface of the lower surface.The maximum displacement and the maximum equivalent stress of the left and right articular discs in the edge-to-edge occlusion and the interposition of tooth tips were similar.The maximum displacement was 0.031,0.030,0.028,and 0.018 mm,and the maximum equivalent stress was 2.87,2.30,2.73,and 1.71 MPa,respectively.(4)The results showed that the Gyroid structure with a wall thickness of 650 μm was consistent with the mechanical properties of the mandible,which reduced the strength of the titanium alloy and reduced the damage of the articular disc caused by the customized Gyroid condylar prosthesis.
4.Design of customized Gyroid condylar prosthesis and finite element analysis of articular disc
Tingting JIANG ; Danyu LIU ; Zhixiu JIANG ; Yuchen JI ; Yilin CAO ; Yucheng SU ; Xinyu WANG
Chinese Journal of Tissue Engineering Research 2025;29(28):6003-6011
BACKGROUND:Condylar prosthesis replacement,as one of the surgical methods for the treatment of temporomandibular joint diseases,not only needs to restore the morphology and function,but also needs to ensure long-term stable application.OBJECTIVE:To design finite element analysis of a customized Gyroid condylar prosthesis.METHODS:Gyroid structure specimens with different wall thicknesses(250,350,450,550,650,and 750 μm)were designed by software.Finite element simulation compression experiments were carried out to test the elastic modulus of the specimens.The Gyroid structure wall thickness range that matches the elastic modulus of mandibular cancellous bone and whose pore size meets the osteogenesis conditions was screened out.This range was subdivided and Gyroid structure specimens were made using 3D printing technology.Mechanical compression experiments were carried out on a universal testing machine.The Gyroid structure wall thickness that meets the mechanical properties of mandibular bone,has an easier osteogenesis and a smaller strength was screened out by elastic modulus and compressive strength,and subsequent experiments were carried out.A three-dimensional model of a customized Gyroid condylar prosthesis was designed,and the finite element analysis of the blade jaw position and cusp interdigitation position of the model under natural occlusion was simulated.RESULTS AND CONCLUSION:(1)Finite element analysis results showed that with the increase of wall thickness,the elastic modulus of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 350,450,550,650,and 750 μm matched the elastic modulus of mandibular cancellous bone.Since the subsequent experiments needed to be subdivided into groups and the pore size of the 550,650,and 750 μm wall thickness group(pore size 800-1 000 μm)was within the osteogenesis range.Gyroid structure specimens with wall thickness of 550,600,650,700,and 750μm were selected for mechanical compression experiments on a universal testing machine.(2)The results of mechanical compression experiments showed that with the increase of wall thickness,the elastic modulus and compressive strength of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 550,600,and 650 μm was within the elastic modulus of the mandibular cancellous bone.Finally,the wall thickness of 650 μm and the pore size of 900 μm were selected to construct the three-dimensional model of the mandibular customized Gyroid condylar prosthesis.(3)The results of finite element analysis of three-dimensional model of the mandibular customized Gyroid condylar prosthesis showed that the stress of the articular disc in the edge-to-edge occlusion was mainly concentrated on the lower surface of the anterior middle band,and the stress of the articular disc in the interposition of tooth tips was mainly concentrated on the lateral surface of the lower surface.The maximum displacement and the maximum equivalent stress of the left and right articular discs in the edge-to-edge occlusion and the interposition of tooth tips were similar.The maximum displacement was 0.031,0.030,0.028,and 0.018 mm,and the maximum equivalent stress was 2.87,2.30,2.73,and 1.71 MPa,respectively.(4)The results showed that the Gyroid structure with a wall thickness of 650 μm was consistent with the mechanical properties of the mandible,which reduced the strength of the titanium alloy and reduced the damage of the articular disc caused by the customized Gyroid condylar prosthesis.
5.Personalized GYROID condylar prosthesis:design and finite element analysis
Danyu LIU ; Tingting JIANG ; Zhixiu JIANG ; Yuchen JI ; Yilin CAO ; Lei WANG ; Yucheng SU ; Xinyu WANG
Chinese Journal of Tissue Engineering Research 2025;29(17):3548-3556
BACKGROUND:Currently,the mandibular joint prosthesis manufactured at home and abroad needs to rely on screws to fix the condylar part of the prosthesis during the replacement process,and the retention hole is reserved to facilitate the operation during the operation.However,due to the lack of personalized jaw design,the reattachment plate may not fit the jaw,resulting in screw loosening and dislocation.Therefore,personalized condylar prosthesis replacement is of great value in the repair of the temporomandibular joint.OBJECTIVE:To design a personalized condylar prosthesis with an internal GYROID for mandibular condylar repair and reconstruction.METHODS:The GYROID structure was selected in the Rhinoceros 7 software with the single cell size of 6 mm and the wall thickness of 0.2,0.3,0.4,0.5,0.6,0.7,0.8 mm.The mechanical properties of the GYROID structure were analyzed by finite element method.3D printing of GYROID structural test specimens with different wall thickness(0.2,0.3,0.4,0.5,0.6,0.7,and 0.8 mm)was performed to test the mechanical properties of the specimens through room temperature compression experiments.A wall thickness value conforming to the range of mandibular mechanical properties was selected through finite element analysis and room temperature compression test results.An adult male mandibular CT data were used for inverse modeling to design a condylar prosthesis with an internal GYROID.Finite element analysis was used to simulate the movement of the apical staggered position and the opposite-blade jaw position after condylar prosthesis replacement.RESULTS AND CONCLUSION:(1)The results of finite element analysis and room temperature compression experiment showed that the elastic modulus of the GYROID structure increased with the increase of wall thickness.The elastic modulus of the GYROID structure with wall thickness of 0.5-0.7 mm was within the range of the elastic modulus of the mandible(1.5-4.0 GPa).Therefore,the 6 mm monocellular GYROID structural model with a wall thickness of 0.6 mm was selected for the design of the condylar prosthesis.(2)The results of finite element analysis showed that the stress distribution of mandibular model was symmetrical.The stress distribution of the two types of occlusion was roughly the same,and the stress peak was not significantly different.The stress concentrated in the neck of the condylar prosthesis,and the stress on the replacement side was slightly larger than that on the healthy side.The maximum equivalent stress of the whole internal fixation model was 269.34 MPa,and the maximum equivalent stress of the screw was 20.14 MPa.The equivalent stress and equivalent strain values of the prosthesis were greater than that of the opposite edge jaw position when the tooth tip was interlaced.The equivalent stress and equivalent strain values of the screw were smaller than that of the opposite edge jaw position when the tooth tip was interlaced.(3)The results showed that the design and retention of the personalized GYROID condylar prosthesis were good,which was consistent with the mechanical conduction of the mandible.
7.Investigation on quality of disinfection in the SARS-CoV-2 nucleic acid sampling sites in Shanghai, 2022
Yucheng ZHANG ; Junhua FAN ; Liang TIAN ; Ning JIANG ; Xiaofan JI ; Lyulan HUANG ; Xing ZHANG ; Renyi ZHU
Shanghai Journal of Preventive Medicine 2023;35(5):505-507
ObjectiveTo investigate the quality of disinfection in the SARS-CoV-2 nucleic acid sampling sites in Shanghai. MethodsSwab samples of medical staff’ hands and environments of different SARS-CoV-2 nucleic acid sampling sites were collected from July to September 2022, with the total number of bacterial colonies cultured and counted. ResultsA total of 728 swab samples were collected from 69 sampling sites. The median total number of bacterial colonies on hand surface, object surface and air samples were 0 CFU·cm-2, 0 CFU·cm-2, and1 CFU·(petri dish∙5 min)-1, respectively, and P95 was 13 CFU·cm-2, 5.3 CFU·cm-2, and 17.8 CFU·(culture vessel∙5 min)-1, respectively. According to the GB 15982‒2012 Hygienic Standard for Disinfection in Hospitals class Ⅳ environment, 680 samples met the standard (93.4%). Furthermore, 96.9%, 92.0%, and 92.2% of the samples in the sampling sites of tertiary/secondary hospitals, community health centers, and community convenience sampling sites met the standard, respectively. Quality of disinfection did not differ significantly across these sampling sites. ConclusionThe quality of disinfection in the SARS-CoV-2 nucleic acid sampling sites in Shanghai is generally good. Additionally, hand hygiene of medical staff and disinfection on object surface in some sampling sites need to be strengthened.
8.Expert consensus on the bone augmentation surgery for alveolar bone defects
ZHANG Fugui ; SU Yucheng ; QIU Lixin ; LAI Hongchang ; SONG Yingliang ; GONG Ping ; WANG Huiming ; LIAO Guiqing ; MAN Yi ; JI Ping
Journal of Prevention and Treatment for Stomatological Diseases 2022;30(4):229-236
Alveolar bone is an important anatomic basis for implant-supported denture restoration, and its different degrees of defects determine the choices of bone augmentation surgeries. Therefore, the reconstruction of alveolar bone defects is an important technology in the clinical practice of implant restoration. However, the final reconstructive effect of bone quality, bone quantity and bone morphology is affected by many factors. Clinicians need to master the standardized diagnosis and treatment principles and methods to improve the treatment effect and achieve the goal of both aesthetic and functional reconstruction of both jaws. Based on the current clinical experience of domestic experts and the relevant academic guidelines of foreign counterparts, this expert consensus systematically and comprehensively summarized the augmentation strategies of alveolar bone defects from two aspects: the classification of alveolar bone defects and the appropriate selection of bone augmentation surgeries. The following consensus are reached: alveolar bone defects can be divided into five types (Ⅰ-0, Ⅰ-Ⅰ, Ⅱ-0, Ⅱ-Ⅰ and Ⅱ-Ⅱ) according to the relationship between alveolar bone defects and the expected position of dental implants. A typeⅠ-0 bone defect is a bone defect on one side of the alveolar bone that does not exceed 50% of the expected implant length, and there is no obvious defect on the other side; guided bone regeneration with simultaneous implant implantation is preferred. Type Ⅰ-Ⅰ bone defects refer to bone defects on both sides of alveolar bone those do not exceed 50% of the expected implant length; the first choice is autologous bone block onlay grafting for bone increments with staged implant placement or transcrestal sinus floor elevation with simultaneous implant implantation. Type Ⅱ-0 bone defects show that the bone defect on one side of alveolar bone exceeds 50% of the expected implant length, and there’s no obvious defect on the other side; autologous bone block onlay grafting (thickness ≤ 4 mm) or alveolar ridge splitting (thickness > 4 mm) is preferred for bone augmentation with staged implant placement. Type Ⅱ-Ⅰ bone defects indicate that the bone plate defect on one side exceeds 50% of the expected implant length and the bone defect on the other side does not exceed 50% of the expected implant length; autologous bone block onlay grafting or tenting techniques is preferred for bone increments with staged implant implantation. Type Ⅱ-Ⅱ bone defects are bone plates on both sides of alveolar bone those exceed 50% of the expected implant length; guided bone regeneration with rigid mesh or maxillary sinus floor elevation or cortical autologous bone tenting is preferred for bone increments with staged implant implantation. This consensus will provide clinical physicians with appropriate augmentation strategies for alveolar bone defects.
9.Molecular Characteristics and Potent Immunomodulatory Activity of Fasciola hepatica Cystatin
Kai ZHANG ; Yucheng LIU ; Guowu ZHANG ; Xifeng WANG ; Zhiyuan LI ; Yunxia SHANG ; Chengcheng NING ; Chunhui JI ; Xuepeng CAI ; Xianzhu XIA ; Jun QIAO ; Qingling MENG
The Korean Journal of Parasitology 2022;60(2):117-126
Cystatin, a cysteine protease inhibitor found in many parasites, plays important roles in immune evasion. This study analyzed the molecular characteristics of a cystatin from Fasciola hepatica (FhCystatin) and expressed recombinant FhCystatin (rFhcystatin) to investigate the immune modulatory effects on lipopolysaccharide-induced proliferation, migration, cytokine secretion, nitric oxide (NO) production, and apoptosis in mouse macrophages. The FhCystatin gene encoded 116 amino acids and contained a conserved cystatin-like domain. rFhCystatin significantly inhibited the activity of cathepsin B. rFhCystatin bound to the surface of mouse RAW264.7 cells, significantly inhibited cell proliferation and promoted apoptosis. Moreover, rFhCystatin inhibited the expression of cellular nitric oxide, interleukin-6, and tumor necrosis factor-α, and promoted the expression of transforming growth factor-β and interleukin-10. These results showed that FhCystatin played an important role in regulating the activity of mouse macrophages. Our findings provide new insights into mechanisms underlying the immune evasion and contribute to the exploration of potential targets for the development of new drug to control F. hepatica infection.
10. Modeling of mongolian acupuncture upper limb simulation system based on virtual reality techniques
Chinese Journal of Tissue Engineering Research 2020;24(11):1745-1749
BACKGROUND: Training for acupuncture manipulation is an important step from theory to clinical practice in Mongolian medicine. OBJECTIVE: To establish mechanical models related to different Mongolian acupuncture techniques of the upper limb acupoints in a virtual environment, and to demonstrate the Mongolian acupuncture process of upper limb acupoints at multiple levels. METHODS: A professional from the Mongolian Medical College of Inner Mongolia Medical University performed a demonstration for Mongolian acupuncture of the forearm acupoints via perpendicular insertion (needle insertion at a 90° angle to the skin), oblique insertion (needle insertion at a 45° angle to the skin), and cruciform insertion (needle rotation after insertion into the skin). Information was collected with ATP-IV acupuncture manipulation parameter tester within 10 seconds of acupuncture. The scanning conditions were voltage 9 V and current 250 mA, and the remaining parameters were set to the default value. The voltage-time diagram was plotted based on X, Y and Z axis sampling information, and the acupuncture process model was established as previously reported. Biomechanical analysis was performed on the modeling of the Mongolian acupuncture process. The implementation of the research program was in line with the relevant ethical requirements of Inner Mongolia Medical University. RESULTS AND CONCLUSION: The parameters of perpendicular, transverse, and cross-shaped insertion were measured by the ATP-IV acupuncture manipulation parameter tester. The axial force of the needle raised rapidly after the needle tip touched the soft tissue surface, and dropped sharply, accompanied by the sense of frustration, after piercing the soft tissue. Then the resistance of the needle tended to be flat due to the soft tissue elasticity and friction. These findings were basically consistent with the biomechanical results reported by Okamura. Compared with the complicated acupuncture manipulation of traditional Chinese medicine, the acupuncture methods described in the Mongolian medical literature, characterized by simple operation and simple appliance, only include one three-step acupuncture technique combined with hand feeling and eight acupuncture techniques combined with acupoints.


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