Loading...

Table of Content

    08 March 2023, Volume 27 Issue 7 Previous Issue    Next Issue
    For Selected: Toggle Thumbnails
    Design and optimization of bone trabecular structure with triply periodic minimal surfaces
    Liu Jiaxin, Jia Peng, Men Yutao, Liu Lu, Wang Yeming, Ye Jinduo
    2023, 27 (7):  992-997.  doi: 10.12307/2023.076
    Abstract ( 508 )   PDF (2113KB) ( 111 )   Save
    BACKGROUND: Bone tissue engineering scaffolds have been widely used in recent years, but their stability and controllability are poor, which may produce stress concentration easily. Triply periodic minimal surfaces have many advantages, such as porosity, smoothness, connectivity, diversity and controllability, which provide a new idea for the design and application of bone tissue scaffolds.
    OBJECTIVE: To construct bone trabecular structure based on implicit surface method and optimize the structure by using finite element numerical simulation and topology optimization technology.
    METHODS: (1) Based on the parameterization of implicit surface method and modeling S-P, D and G trabecular structures of triply periodic minimal surface were constructed. (2) Compression simulation of the constructed trabecular bone structure was carried out using finite element numerical simulation method. (3) The structure optimization of S-P bone trabecular structure was carried out by using variable density method and Solid Isotropic Material with Penalization interpolation model. 
    RESULTS AND CONCLUSION: (1) The stress nephogram showed that the three trabecular structures exhibited larger stress values at the intersection of the unit structures. The S-P type appeared at the radial connection of the unit. The G type appeared at the axial connection. The D type appeared at the axial and radial connection. The equivalent stresses of S-P, G and D structures were 105.07, 694.78 and 637.36 MPa, respectively. (2) The displacement nephogram showed that the displacement of the three trabecular structures close to the displacement surface was the largest and decreased along the axial direction. The total deformation of the S-P type was smaller than that of the G and D types. (3) The porosity of the three trabecular bone structures was higher than 50%, with the highest porosity of the S-P type (90.7%) and an aperture of 0.63 mm. Bone ingrowth performance was better than G and D types. (4) After topology optimization, the equivalent stress of S-P structure was 149.11 MPa, the mass of which was reduced by 13.9%, which met the design requirements of bone tissue scaffold. (5) Therefore, the method of the design of bone trabecular structure that combines triply periodic minimal surface parametric modeling with finite element numerical simulation and topology optimization provides a new idea for the surface structure design of bone implants. 
    Figures and Tables | References | Related Articles | Metrics
    Effect of hydrogel-loaded simvastatin microspheres on osteoblast proliferation and differentiation
    Liu Xiaolin, Mu Xinyue, Ma Ziyu, Liu Shutai, Wang Wenlong, Han Xiaoqian, Dong Zhiheng
    2023, 27 (7):  998-1003.  doi: 10.12307/2023.033
    Abstract ( 415 )   PDF (1311KB) ( 92 )   Save
    BACKGROUND: The number of patients with periodontitis increases year by year, and the use of traditional periodontal treatment cannot restore the periodontal soft and hard tissue. Therefore, it is necessary to prepare a drug sustained-release material to assist the treatment of periodontitis and restore the damaged soft and hard tissues of periodontitis.
    OBJECTIVE: To prepare bovine serum albumin microspheres composite hydrogel material, detect the dual sustained release effect on simvastatin, and further study the effect of the composite material on the adhesion and proliferation of osteoblasts. 
    METHODS: (1) Bovine serum albumin microspheres loaded with simvastatin were prepared by solvent removal method. The morphology of microspheres was observed by transmission electron microscopy and scanning electron microscopy and the particle size of microspheres was measured. The encapsulation rate, drug loading rate and in vitro release of microspheres were detected by a microplate analyzer. (2) Simvastatin albumin microspheres were loaded into the prepared hydrogel, and in vitro drug release from hydrogels was detected using a microplate reader. The morphology of the composite material was observed by scanning electron microscopy. The hydrogel extract was used to culture MC3T3-E1 cells. The proliferation of osteoblasts was detected by CCK-8 assay. The alkaline phosphatase expression in osteoblasts was detected by alkaline phosphatase kit. 
    RESULTS AND CONCLUSION: (1) Transmission electron microscopy showed that bovine serum albumin microspheres and blank microspheres loaded with simvastatin were smooth, spherical and dispersed, with no obvious aggregation. The particle size of bovine serum albumin microspheres was uniform, and 80% of the microspheres had a particle size between 0.2 μm and 0.8 μm. Scanning electron microscopy showed that the microspheres were smooth and spherical with good dispersion and uniform particle size distribution, ranging from 0.2 μm to 0.8 μm. (2) The encapsulation rate and drug loading rate of simvastatin microspheres were 68.9%-87.5% and 0.95%-1.21%, respectively. (3) Drug-loaded microspheres had the performance of gentle and sustained release of simvastatin. The release curve of simvastatin in the drug-loaded hydrogel is a fast release in the early stage and a slow sustained release process in the later stage, in which the drug-loaded hydrogel can release faster than the drug-loaded microspheres and reach the effective concentration of the drug. The slow release in the later stage maintains the concentration of the drug. (4) Scanning electron microscopy showed that the drug-loaded hydrogel had a porous strip-like structure, which was suitable for the adhesion and growth of osteoblasts, and spherical drug-loaded microspheres could be seen on the surface of the hydrogel. (5) The drug-loaded hydrogel can promote the proliferation and alkaline phosphatase expression of MC3T3-E1 cells. (6) Simvastatin microspheres hydrogel composite had good biocompatibility and could promote the adhesion and proliferation of osteoblasts. 
    Figures and Tables | References | Related Articles | Metrics
    Sustained releasing of pyrazinamide, capreomycin, moxifloxacin and amikacin loaded bone cement in vitro
    Yuan Hucheng, Ding Yongguo, Ma Xuehua, Ma Wenxin, Sun Jianmin, Wang Zili, Jin Weidong
    2023, 27 (7):  1017-1022.  doi: 10.12307/2023.080
    Abstract ( 511 )   PDF (935KB) ( 68 )   Save
    BACKGROUND: Oral anti-tuberculosis drugs have serious systemic side effects after removal of bone and joint tuberculosis lesions. It is imperative to seek a sustained-release drug system that can not only save drug dosage, but also increase local drug concentration in lesions and reduce systemic blood drug concentration. 
    OBJECTIVE: To observe the sustained-release properties of polymethyl methacrylate bone cement loaded with antituberculosis drugs pyrazinamide, capreomycin, moxifloxacin, and amikacin in PBS artificial simulated body fluid. 
    METHODS: Polymethyl methacrylate bone cement Palacos R powder was mixed with antituberculosis drugs pyrazinamide, capreomycin, moxifloxacin, and amikacin in the proportion of 40 g:1.5 g and 40 g:2.5 g, respectively. The 20 mL of liquid monomer were added to prepare 8 groups of anti-tuberculosis drug-loaded bone cement standard specimens, with 5 samples in each group. In the control group, 40 g bone cement powder and 20 mL liquid monomer were mixed in the same way to prepare 5 standard bone cement samples without drugs. The drug was soaked in PBS and placed in 37 ℃ constant temperature water bath oscillator. The extract was taken at set time points. The drug concentration of each group was determined by high performance liquid chromatography. 
    RESULTS AND CONCLUSION: (1) The time of the lowest drug release concentration in PBS artificial simulated body fluid of pyrazinamide 1.5 g group, pyrazinamide 2.5 g group, capreomycin 1.5 g group, capreomycin 2.5 g group, moxifloxacin 1.5 g group, moxifloxacin 2.5 g group, amikacin 1.5 g group and amikacin 2.5 g group was 45, 60, 150, 150, 120, 120, 60 and 90 days, respectively. Among these groups, the capreomycin 1.5 g group, capreomycin 2.5 g group, moxifloxacin 1.5 g group, moxifloxacin 2.5 g group, and amikacin 2.5 g group had a longer drug release period, while the control group had no drug release. (2) It is concluded that polymethyl methacrylate bone cement loaded with capreomycin (1.5 g and 2.5 g), moxifloxacin (1.5 g and 2.5 g), and amikacin (2.5 g) has a long release cycle and good release performance.
    Figures and Tables | References | Related Articles | Metrics
    Antibiotic bone cement intramedullary nail prepared using 3D printed mold for the treatment of long bone infection in lower limbs
    Zhao Wei, Feng Wei, Yang Tieyi, Ren Wei, Wang Yuxin, Lyu Huicheng, Chang Zhiqiang, Feng Xiaodong, Wang Ziheng, Guo Shibing
    2023, 27 (7):  1023-1030.  doi: 10.12307/2023.026
    Abstract ( 426 )   PDF (1552KB) ( 223 )   Save
    BACKGROUND: Due to many problems in the preparation technology and intraoperative operation of antibiotic cement rods or nails, their applications are still limited. 
    OBJECTIVE: To explore the clinical effect of antibiotic bone cement intramedullary nail implantation prepared using 3D printed molds combined with debridement in the treatment of postoperative infection in the lower extremities long bone infection. 
    METHODS: From October 2018 to October 2020, 16 patients with femoral and tibial infection were treated by antibiotic bone cement intramedullary nail medullary cavity implantation made of 3D printed mold. There were 10 cases of femur and 6 cases of tibia. According to Cierny Mader’s classification of bone infection, there were 4 cases of type III, 7 cases of type I + type III, and 5 cases of type I + type IV. The time from the first (surgical) treatment to the initial infection was 0.5-120 months and the duration of infection was 0.5-118 months. In the intramedullary nail fixation group, the soft tissue scar, granulation tissue and dead bone at the infected fracture end and the interlocking screw were completely removed after the removal of intramedullary nail. The soft tissue involved in infection was removed for patients with sinuses and soft tissue abscesses. The necrotic and inflammatory tissues in the medullary cavity were removed with soft drill and examined. Antibiotic bone cement intramedullary nail was implanted after repeated irrigation of the medullary cavity. In the non-intramedullary nail fixation or non-fixation group, the infected broken end or focal infection site was cut open. The sinuses and infected soft tissue were removed together. The pulp was expanded according to the standard procedures of femoral or tibial intramedullary nail fixation. The other procedures were the same as before. 
    RESULTS AND CONCLUSION: (1) All patients were followed up for 12-24 months. There was no recurrence of infection or complications. (2) One case was infected with malunion of fracture. The range of motion of the knee joint was 50 degrees in a patient with femoral fracture. (3) Bacterial culture and histological examination of intramedullary tissue obtained from six patients with bone cement nail removal were all negative. (4) The hospital stay of all patients was 7-53 months. The medical expenses ranged from 6 000 to 49 400 yuan. (5) It is concluded that a medullary debridement in combination with antibiotic bone cement intramedullary nail implantation is an effective treatment for long bone infection. The application of this technique in the treatment of lower limb long bone infection can shorten the operation time and greatly reduce the medical cost. Level of evidence: therapeutic research level IV.
    Figures and Tables | References | Related Articles | Metrics
    Finite element analysis of elastic ankle brace performance
    Guo Tingting, Xie Hong, Xu Guanghua
    2023, 27 (7):  1031-1037.  doi: 10.12307/2023.071
    Abstract ( 491 )   PDF (3059KB) ( 114 )   Save
    BACKGROUND: Ankle injury is a high incidence type of sports injury. Common sequelae include chronic ankle instability and repeated ankle sprain. Long-term development will form secondary arthritis, resulting in ankle dysfunction. Elastic ankle brace is a common protective device used to prevent ankle injury.
    OBJECTIVE: To predict the influence of elastic ankle brace on stress of the ankle internal tissue under different motion states using finite element method so as to the influence of elastic ankle brace on ankle protection performance. 
    METHODS: A healthy ankle three-dimensional finite element model was constructed using reverse engineering technology, based on CT image sequences. The plantar pressure test and anterior drawer test were utilized to validate the effectiveness of the model. Ankle varus and valgus were simulated in the absence of ankle brace and under the action of three different kinds of elastic ankle brace to extract overall ankle displacement and stress distribution of the internal tissue.
    RESULTS AND CONCLUSION: (1) The simulation results of plantar pressure of foot and ankle finite element model were in good agreement with the experimental results. The simulation results of anterior drawer test were in good agreement with the corpse experiment in literature, which proved the validity of this model. (2) Elastic ankle brace reduced the overall displacement of ankle and the peak stress of internal tissue in the states of varus, valgus, internal rotation and external rotation, and the effect was enhanced with the increase of the elastic modulus of the material. It demonstrates the protective effect of elastic ankle brace and provides a reference for the digital evaluation of the protective effect of elastic ankle brace.
    Figures and Tables | References | Related Articles | Metrics
    Efficacy of gutta-percha splint on a rabbit fracture model
    Zhang Wei, Huang Zhichao, Zhao Ruifeng, Liang Huan, Ma Yufeng, Shen Yanguang, Zhong Honggang, Chen Zhaojun, Zhang Jichuan, Chen Weiheng
    2023, 27 (7):  1055-1061.  doi: 10.12307/2023.014
    Abstract ( 388 )   PDF (2771KB) ( 47 )   Save
    BACKGROUND:  Gutta-percha has low yield strength and shows hard and tough mechanical properties. On this basis, a sports protective gear that can be freely shaped according to the body shape has been developed, and it has been preliminarily confirmed that this performance can reduce the damage to athletes caused by external impact forces.
    OBJECTIVE: To evaluate the effect of gutta-percha splint on fracture fixation.
    METHODS: Thirty-five adult male New Zealand rabbits were used to establish closed fracture models of the left tibia by the modified three-point stress method. Totally 30 successful models were randomly divided into two groups (n=15) and fixed with gutta-percha splint and gypsum, respectively. The effects of the two external fixation methods were compared by X-ray imaging and fracture healing was observed at 2 hours, 4 and 6 weeks after fixation. After 6 weeks of fixation, the tibia specimens were observed for gross and histological morphology.
    RESULTS AND CONCLUSION: (1) X-ray films: Clear fracture line was seen 2 hours after fixation, without obvious periosteal reaction. After 4 weeks, the fracture line became blurred, and a large area of spindle low-density callus shadow was seen at the broken end. After 6 weeks, the fracture line nearly disappeared; the callus connected together to form a cortical bone bridge, and the bone marrow cavity was partially canalized, and partially close to recanalization. After 6 weeks, gray value at the fracture site was higher in the gutta-percha splint group than that in the gypsum group (P < 0.05). (2) General observation: In the gutta-percha splint group, except for three rabbits with malunion, the fracture line of the rest of the rabbits basically disappeared; part of the outer callus was absorbed, and the cortical bone density was close to the normal level. In the gypsum group, except for four rabbits with malunion, the fracture line of the rest of the rabbits disappeared, a small part of the outer callus was absorbed, and the cortical bone density was close to the normal level. (3) Histological morphology: In the gutta-percha splint group, new bone trabeculae were thick; the trabecular space was reduced and fused to form lamellar bone, and the medullary cavity had been partially recanalized. In the gypsum group, new bone trabeculae were reticular, forming a woven bone, and a large number of transected small arteries, veins and capillaries could be seen in the medullary cavity. (4) Complications: Within 6 weeks of fixation, the extremity swelling, purple darkening, displacement and malunion, and the number of local pressure ulcers in the gutta-percha splint group tended to be less than those in the gypsum group, but there was no significant difference in statistical analysis (P > 0.05). (5) The results showed that gutta-percha splint could play a similar fixation effect to plaster on the rabbit model of closed tibial fracture. 
    Figures and Tables | References | Related Articles | Metrics
    Biomechanical analysis of All-on-Four and pterygomaxillary implants under different maxillary bone conditions
    Zhu Lin, Gu Weiping, Wang Can, Chen Gang
    2023, 27 (7):  985-991.  doi: 10.12307/2023.035
    Abstract ( 381 )   PDF (1548KB) ( 86 )   Save
    BACKGROUND: Implant fixation has become a more satisfactory repair method for patients. All-on-Four and pterygomaxillary implants can meet the implant requirements under certain conditions. At present, there is no biomechanical comparative analysis of the two schemes under different bone quality conditions. 
    OBJECTIVE: To explore the appropriate implant scheme, three-dimensional finite element analysis was used to compare the stress distribution of All-on-Four and pterygomaxillary implant under different bone conditions.
    METHODS: The cone beam CT data of an edentulous patient with severe maxillary bone deficiency were selected, in order to set up physical models with three kinds of cortical bone thickness (1.0, 1.5, 2.0 mm) and two cancellous bone densities (high density, low density). For each model, All-on-Four and pterygomaxillary implant schemes were designed respectively. A total of 12 models were established and 200 N vertical static forces were applied to the bilateral posterior teeth to calculate the von Mises stress values of implants and cortical bone, together with the deformation of titanium framework. 
    RESULTS AND CONCLUSION: (1) The von Mises stress values of implants and cortical bone were at the most distal site and the deformation of titanium framework was at the distal end of the stent in All-on-Four and pterygomaxillary implant designs. (2) Under the same cancellous bone density, the von Mises stress values of implants and cortical bone and the deformation of titanium framework were the highest in 1 mm cortical bone, and decreased with the increase of cortical bone thickness in All-on-Four and pterygomaxillary implant designs. (3) Under the same implant design, the von Mises stress values of implant, cortical bone and the deformation of titanium framework were larger in low-density cancellous bone than those of high-density cancellous bone. (4) Under the condition of the same bone, the von Mises stress values of implant, cortical bone and titanium framework deformation in pterygomaxillary implant group were lower than those in All-on-Four group (P < 0.05). (5) The results showed that the increase of cortical bone thickness and cancellous bone density could reduce the stress concentration of implants and cortical bone and the deformation of titanium framework. From the perspective of biomechanics, the pterygomaxillary implant was more favorable for long-term prognosis than All-on-Four.
    Figures and Tables | References | Related Articles | Metrics
    Three-dimensional finite element analysis of stress distribution in different smooth collar implants
    Sun Jiangwei, Wang Junxiang, Baibujiafu·Yellisi, Dai Huijuan, Nijati·Turson
    2023, 27 (7):  1004-1011.  doi: 10.12307/2023.078
    Abstract ( 387 )   PDF (2869KB) ( 93 )   Save
    BACKGROUND: In oral implant repair, soft tissue level implants are different from bone level implants, which adopt non-embedded surgical methods. A good neck design can promote bone bonding or reduce marginal bone absorption and facilitate the formation of stable soft tissue sealing. Therefore, the neck structure design of implants is one of the key factors for the success of implant repair.
    OBJECTIVE: To simulate and analyze the stress distribution of implant components and implant-bone interface during the restoration of mandibular molars with four different smooth collar implants using three-dimensional modeling and finite element analysis software. 
    METHODS: The cone-beam CT image data of a patient undergoing mandibular first molar implantation were selected, and the mandible model was established by Mimics 21.0 software. The mandible model was imported into Solidworks 2018 software. Smooth neck implant models were constructed as follows: the standard conventional cervical implant (2.8 mm in height, 4.8 mm in diameter), standard wide cervical implant (2.8 mm in height, 6.5 mm in diameter), aesthetic conventional neck implant (1.8 mm in height, 4.8 mm in diameter), and aesthetic wide neck implant (1.8 mm in height, 6.5 mm in diameter). The four models were repaired with pure titanium base table and zirconia full-crown screw fixation. The von-Mises stress distribution of implant components and the implant-bone interface in four groups of different smooth collar implants were compared and analyzed under vertical and oblique loadings. 
    RESULTS AND CONCLUSION: (1) Whether it was vertical loading or oblique loading, the peak values of von-Mises stress were located in the neck region of the implant, and the peak values of von-Mises stress at the implant-bone interface were located in the cortical bone region of the neck region of the implant. (2) When using the same smooth collar implant, compared with the vertical loading group, the peak values of Von-Mises stress were greater in the four different smooth collar implants in the oblique loading group. (3) Under vertical or oblique loading, the maximum von-Mises stress of the standard implant group was greater than that of the standard implant group, and the maximum von-Mises stress of the aesthetic implant group was lower than that of the aesthetic implant group. (4) The maximum von-Mises stress on the implant-bone interface in the wide-neck standard implant group was lower than that in the other smooth cervical implant groups, regardless of vertical or oblique loading. (5) The results showed that the stress distribution of implant components and implant-bone interface was different with different smooth collar implants.
    Figures and Tables | References | Related Articles | Metrics
    Selective laser melting forming process and deformation experiment of titanium alloy full crown
    Wang Shuxiang, Wu Quan, Zhou Xiaosong, Kuang Xiantao
    2023, 27 (7):  1012-1016.  doi: 10.12307/2023.038
    Abstract ( 392 )   PDF (1225KB) ( 30 )   Save
    BACKGROUND: Full crowns have variable shapes and sizes, and are used for tooth restoration. This type of thin-walled parts usually requires high precision, light weight and thin wall thickness, but it is easy to deform during forming and reduce the accuracy of the workpiece.
    OBJECTIVE: To explore the influence of different energy densities on the deformation of titanium alloy full crowns, and obtain the optimal combination of process parameters for forming titanium alloy full crowns. 
    METHODS: The full crown of Ti-6Al-4V titanium alloy was formed by selective laser melting. The influence of energy densities (77.38, 48.15, 32.83, 71.76, 46.97, 61.51, 68.18, 85.71, 55.56 J/mm3) on deformation was studied. The process parameters were optimized, and the parts printed after parameter optimization were heat treated.
    RESULTS AND CONCLUSION: Deformation experiments showed that a reasonable combination of process parameters could reduce the degree of deformation of the formed parts. When the energy density was 68.18 J/mm3 (laser power, scanning speed, and scanning distance were 180 W, 800 mm/s, 0.11 mm, respectively), the average value of deformation of the specimen formed at this energy density was 1.594 mm, which was smaller than the deformation of the cantilever beam at other energy densities. Under the optimized combined process parameters, the average amount of deformation after heat treatment was 0.355 mm; the average roughness was 8.306 μm; the average hardness was 345 HV, in line with industry standards. The research results provide experimental data and theoretical basis for forming high-quality thin-walled parts. 
    Figures and Tables | References | Related Articles | Metrics
    Simulation analysis of stress distribution of NRT FILES in curved root canals
    Jiang Yifang, Cai Qimin, Chu Zhengyi, Qin Min, Shen Yurong, Gu Yuanping
    2023, 27 (7):  1038-1042.  doi: 10.12307/2023.072
    Abstract ( 420 )   PDF (1696KB) ( 27 )   Save
    BACKGROUND: In root canal therapy, the fatigue fracture of NiTi alloy instruments is often caused by stress exceeding the elastic limit of metal plastic deformation or repeated bending at the root canal bend. 
    OBJECTIVE: To explore the stress distribution on the inner wall of root canals when NRT FILES are used as root canal preparation materials, and to examine the stress concentration area.
    METHODS: Solidworks software was used for 3D modeling of NRT FILES to simulate the state of the instruments in real oral environment. Six groups of simplified root canal models were established: (1) Bending angle of 30°, bending radius of 5 mm, root apex bending; (2) Bending angle of 30°, bending radius of 5 mm, middle root bending; (3) Bending angle of 30°, bending radius of 2 mm, root apex bending; (4) Bending angle of 30°, bending radius of 2 mm, middle root bending; (5) Bending angle of 45°, bending radius of 5 mm, root apex bending; (6) Bending angle of 45°, bending radius of 2 mm, root apex bending. The simplified root canal model and the root canal file model were assembled, and the stress points and stress distribution on the inner wall of the root canal were analyzed. 
    RESULTS AND CONCLUSION: The maximum stresses of root canal files in groups (1)-(6) were 1 185, 1 354, 1 371, 1 678, 1 335, and 2 557 MPa, and the maximum strains were 0.010 36, 0.013 54, 0.013 79, 0.016 48, 0.013 45, and 0.022 03, respectively. Different bending parts of root canals could affect the stress borne by the root canal file. In root canal therapy, the lower the root canal file went down along the root canal, the greater the contact radius between these two pieces, the worse the rigidity of the root canal file, the greater the stress it bore, and the easier it was to fracture. The smaller the root canal bending radius, the greater the stress bore on the root canal file. The smaller the bending angle of the root canal, the greater the stress on the file. In the curved part of the root canal tip, the root canal file bore greater stress when the bending radius of the root canal was small, and it was more prone to fracture; similarly, in the curved part of the middle of root canal, the root canal file also bore greater stress with small bending radius. Therefore, it is necessary to pay extra attention to the bending degree of the root canal and select an appropriate root canal file for root canal treatment. 
    Figures and Tables | References | Related Articles | Metrics
    Bioactivity of phase-transition lysozyme for surface modification of zirconia all-ceramic implant material mediating hydroxyapatite coating
    Zhang Tingting, Liu Juan, Zhang Xu
    2023, 27 (7):  1043-1049.  doi: 10.12307/2023.040
    Abstract ( 364 )   PDF (2218KB) ( 50 )   Save
    BACKGROUND: Zirconium implants are used in the field of oral implants due to good biocompatibility. Because of its biological inertness, the surface of the implant needs to be modified to improve its bioactivity. Hydroxyapatite coating is a widely used modification technique for implant surfaces.
    OBJECTIVE: The phase-transition lysozyme was modified on the zirconia surface, based on which a hydroxyapatite coating was constructed to confer its bioactivity and improve the success rate of implants.
    METHODS: The phase-transition lysozyme solution was dropped onto the surface of the smooth zirconia specimen for 2 hours. The phase-transition lysozyme-modified zirconia specimen was incubated in the simulated body fluid for 10 days to induce the hydroxyapatite coating. The contact angle, roughness and mechanical properties of unmodified zirconia specimens, phase-transition lysozyme-modified zirconia specimens and hydroxyapatite-coated zirconia specimens were tested. The three kinds of zirconia specimens were co-cultured with MC3T3-E1 cells, separately. The cell proliferation and alkaline phosphatase activity were detected. Unmodified zirconia specimens and hydroxyapatite-coated zirconia specimens were co-cultured with MC3T3-E1 cells, separately, and cell adhesion was observed under a scanning electron microscope.
    RESULTS AND CONCLUSION: (1) The contact angle of the hydroxyapatite coating group was smaller than that of the unmodified group (P < 0.05), and the roughness was greater than that of the unmodified group (P < 0.05). There was no significant difference in the Vickers hardness and fracture strength of the three groups of specimens (P > 0.05). (2) CCK-8 assay showed that the absorbance values of cell proliferation in the hydroxyapatite coating group on 3, 5, and 7 days of culture were higher than those in the phase-transition lysozyme group and the unmodified group (P < 0.05). The alkaline phosphatase activity of the hydroxyapatite coating group was higher than that of the phase-transition lysozyme group and the unmodified group at 7 and 14 days of culture (P < 0.05). (3) Scanning electron microscope showed that MC3T3-E1 cells adhered closely to the surfaces of the two kinds of zirconia materials after 12 hours of culture. After 3 days of culture, the number of cells on the surfaces of the two materials increased, and the number of cells in the hydroxyapatite coating group was high and cell junctions appeared. (4) The results show that for zirconia all-ceramic materials, the preparation of hydroxyapatite coating on the basis of phase-transition lysozyme modification can improve its hydrophilicity and cytocompatibility without affecting the mechanical properties of the material.
    Figures and Tables | References | Related Articles | Metrics
    Clear aligner orthodontic therapy of rotated mandibular teeth with different shapes: a three-dimensional finite element analysis
    Li Huiqin, Wang Chunjuan, Wang Yu, Wang Weifeng, Chen Dinggen, Li Na
    2023, 27 (7):  1050-1054.  doi: 10.12307/2023.073
    Abstract ( 469 )   PDF (3168KB) ( 72 )   Save
    BACKGROUND: The rotation is unpredictable tooth movement in clear aligner treatment. Tooth shape can affect the efficiency of tooth de-rotation, but there is no relevant biomechanical study.
    OBJECTIVE: To investigate aligner activation influencing on biomechanics of clear aligner orthodontic therapy of rotated mandibular teeth with different shapes.
    METHODS: A three-dimensional finite element model of mandibular dentition-periodontium-alveolar bone-appliance with highly simulated crown shape was established based on cone-beam computed tomography and intraoral optical scanning data of an adult who had rotated lower central incisor and second premolar. The initial displacement, movement trend and von Mises stress distribution of periodontium of target teeth and adjacent teeth were analyzed when the loading of three different aligner activation of 1.0°, 1.5° and 2.0° was applied to rotated the left lower central incisor (group A) and second premolar (group B).
    RESULTS AND CONCLUSION: (1) The displacement and periodontium stress of target teeth were significantly higher in the group A than those in the group B under different rotation loads. Increasing the aligner activation could improve the efficiency of tooth de-rotation to a certain degree, but the risk of periodontal tissue injury was also increased. It was suggested that aligner activation should not exceed 1.5° for the lower incisor and 2.0° for the lower premolars. (2) In group A, the displacement of meso-adjacent tooth was 65%-105% as much as target tooth. For incisor de-rotation, we should pay attention to the adverse effect on adjacent teeth. (3) During the rotation movement, mesial tipping and slightly intrusive movement of target teeth were observed, and adjacent teeth showed the trend of tipping movement, which required additional measures to strengthen the grip on three-dimensional movement of teeth.
    Figures and Tables | References | Related Articles | Metrics
    Carbon nanomaterials in oral implant
    Xu Xingxing,  Wen Chaoju,  Meng Maohua,  Wang Qinying,  Chen Jingqiao,  Dong Qiang
    2023, 27 (7):  1062-1070.  doi: 10.12307/2023.103
    Abstract ( 666 )   PDF (1040KB) ( 318 )   Save
    BACKGROUND: With the continuous progress and development of oral nanomaterials, a large number of studies have found that carbon nanomaterials are widely used in the field of oral implant. 
    OBJECTIVE: To review the main classification, structural characteristics, osteogenesis, antibacterial, protein/drug carrier and related applications of carbon nanomaterials in oral implant.  
    METHODS: After clarifying the classification of carbon nanomaterials, the Chinese search terms were “graphene/carbon nanotubes/Carbon Nanofibers/carbon nanomaterials, oral implant/osteogenesis and oral cavity/antibacterial and oral cavity/drug loaded and oral cavity”. English search terms were “Graphene/carbon nanotubes/Carbon Nanofibers/carbon nanomaterials, dental implant/osteogenesis AND oral/ antibacterial AND oral/drug loaded AND oral”. The first author searched the relevant articles published from January 1998 to August 2021 in CNKI, Wanfang, VIP, and PubMed databases by computer. The search time limit of some classical articles was extended. Finally, 64 English articles and 9 Chinese articles were included according to the inclusion criteria.
    RESULTS AND CONCLUSION: (1) Carbon nanomaterials are mainly divided into three categories: zero dimensional, one-dimensional and two-dimensional carbon nanomaterials. Because of their unique spatial structure and good physical and chemical properties, they have a great application potential in implant surface coating, scaffold material modification, drug loading, and preparation of barrier membrane. (2) In addition, the osteogenic and antibacterial effects of the material are also conducive to the formation of stable bone integration and good soft tissue sealing. It also has certain research significance in the prevention and treatment of periimplant inflammation. (3) There are many kinds of carbon nanomaterials. Many studies also functionalize carbon nanomaterials and other biomolecular materials into composites, so that some properties can be obtained. In addition, carbon nanomaterials also have antibacterial effect, and graphene is often functionalized with other antibacterial agents (such as silver nanoparticles) to enhance antibacterial performance. (4) In general, graphene, as a typical two-dimensional carbon nanomaterial, has always been a research hotspot in oral implant and other fields. Graphene oxide is a widely used class of graphene derivative materials. It is found that when it is applied to implant surface modification, it has certain research significance in the treatment and prevention of periimplant inflammation. (5) However, the research on the signaling pathway and immune regulation mechanism of stem cell differentiation/osteogenesis induced by carbon nanomaterials is not clear, and the cytotoxicity, degradation and adverse reactions of materials still need to be further studied. (6) At present, a cost-effective, scalable and repeatable process for the preparation of carbon nanomaterials and the evaluation index of material biocompatibility need to be studied. In addition, it is also necessary to further study the significance of carbon nanomaterials in the prevention and treatment of periimplant inflammation when applied to implant surface coating.
    Figures and Tables | References | Related Articles | Metrics
    Application of the interaction between biological scaffolds and macrophages in bone regeneration
    Yang Yitian, Wang Lu, Yao Wei, Zhao Bin
    2023, 27 (7):  1071-1079.  doi: 10.12307/2022.853
    Abstract ( 565 )   PDF (2791KB) ( 297 )   Save
    BACKGROUND: In recent years, the way of repairing tissue defects with biological scaffolds has been widely concerned by scholars. As an external implant, the body inflammatory response is vital for the integration between materials and tissues, in which macrophages serve as important participants and regulators. It is necessary to understand the interaction between biological scaffolds and macrophages, which will have crucial guiding significance for the design of new scaffolds in the future. 
    OBJECTIVE: To review the researches on the interaction between biological scaffolds and macrophages as well as the regulation of this dynamic balance between them.
    METHODS: PubMed, Web of Science, and CNKI were used to search the related articles published from 1971 to 2021. The search terms were “macrophage polarization, M2, foreign body, tissue engineering, scaffolds, mediation, bone, degradation” in English and Chinese. An inductive analysis was conducted in the 76 selected articles on the latest research progress in this field.
    RESULTS AND CONCLUSION: (1) Immune response plays an indispensable role in tissue regeneration and repair. (2) Macrophage is an important regulator of inflammatory response. It will polarize into different phenotypes such as pro-inflammatory or anti-inflammatory according to different microenvironment stimuli. On one hand, the imbalance of macrophage polarization in different stages of inflammatory response will hinder the integration of biological scaffold materials and tissue repair. The high expression of pro-inflammatory macrophages in the early stage of biomaterial implantation is conducive to the integration of biomaterials. In the late stage of inflammation, however, the sustained high expression of pro-inflammatory macrophages will hinder the formation of new bone. On the other hand, the properties of biological scaffolds (composition, hardness, roughness, surface geometry, hydrophilicity, etc.) will affect the polarization direction of macrophages. For example, adjusting the surface morphology of scaffolds cannot change the ideal physical and chemical properties of scaffolds, but promote effectively the polarization of macrophages towards pro-regenerative phenotype and tissue repair. (3) At present, the effect of biological scaffolds on macrophages has been realized by changing the composition, preparation methods and adjusting the physical and chemical properties of scaffolds. However, how to efficiently regulate this dynamic balance is still the focus and our key direction in the future, In particular, how to successfully translate the ideal results of basic research in vitro into practical application in vivo is still under further exploration.
    Figures and Tables | References | Related Articles | Metrics
    Alginate scaffold in articular cartilage repair
    Li Cheng, Zheng Guoshuang, Kuai Xiandong, Yu Weiting
    2023, 27 (7):  1080-1088.  doi: 10.12307/2023.028
    Abstract ( 553 )   PDF (1185KB) ( 84 )   Save
    BACKGROUND: Due to the anatomical and physiological characteristics of articular cartilage, its self-repair ability is limited, so how to repair large cartilage defects (diameter > 4 mm) has become one of the most attractive problems in the medical field. With the development of bio-materials and tissue engineering, the further development of scaffold technology, especially the hydrogel scaffold that simulates the microenvironment of extracellular matrix, provides a new therapeutic idea for the repair of cartilage injury.
    OBJECTIVE: To summarize the properties of alginate, the preparation of alginate saline gel scaffold and the research progress in the repair of cartilage injury.
    METHODS: A computer-based search of Web of Science, PubMed, Wanfang and CNKI was performed for papers published from January 2016 to December 2020 with the key words of “alginate hydrogel; cartilage tissue engineering or chondro*, osteochondral, scaffold” in Chinese and English. According to the inclusion criteria, 60 articles were included for review. 
    RESULTS AND CONCLUSION: (1) Alginate, as negatively charged natural hydrophilic polysaccharide, can endow traditional alginate saline gel with better mechanical properties, adhesion, biodegradability and biocompatibility by modification technology. (2) The modified alginate composite hydrogel scaffold is beneficial to maintain the normal morphology of seed cells, synthesize the corresponding extracellular matrix, promote the expression of cartilage-related genes, and show excellent chondrogenic ability. (3) It has been reported that alginate composite hydrogel scaffold can form cartilage tissue similar to the surrounding normal cartilage in animals and effectively repair the defect. (4) In summary, alginate composite hydrogel scaffold has a good ability to promote cartilage repair, which provides a new therapeutic idea for cartilage tissue engineering. However, this material needs to be supported by more perfect preclinical trial data to promote its clinical transformation process.
    Figures and Tables | References | Related Articles | Metrics
    Regeneration of facial nerve injury repaired by biomaterial nerve conduits
    Xu Cong, Zhao He, Sun Yan
    2023, 27 (7):  1089-1095.  doi: 10.12307/2023.104
    Abstract ( 554 )   PDF (1066KB) ( 70 )   Save
    BACKGROUND: Autologous nerve transplantation is the first choice for repairing the damaged facial nerve and treating facial paralysis, but the donor nerve is limited and will cause certain damage to the donor site. Biomaterial catheter is an important branch of tissue engineering. It provides physical barrier and three-dimensional regeneration channel for the nerve by connecting the nerve broken end, and it is the most potential facial nerve repair method. 
    OBJECTIVE:  To review the application progress of biomaterials used to repair facial nerve injury in recent years.
    METHODS: “biomaterials, nerve conduits, facial nerve” were used as the Chinese and English search terms. Relevant articles were searched on CNKI and PubMed from inception to January 2022. According to the inclusion and exclusion criteria, 68 relevant articles were finally included. 
    RESULTS AND CONCLUSION: (1) At present, biological material nerve conduits used for facial nerve injury can be roughly divided into acellular materials and degradable materials. Acellular materials mainly include arteries, veins, and muscles, while degradable materials mainly include collagen, polyglycolic acid, polycaprolactone, silk protein, chitosan, and graphene. (2) Vein and collagen are the two materials most studied at present. After combining with stem cells and neurotrophic factors, their nerve regeneration effect is significantly enhanced, but there is still a certain gap between them and autologous nerve transplantation. (3) Graphene is more active and more easily combined with neurotrophic substances. It has anti-inflammatory effects and promotes the increase of M2 macrophages, which is conducive to nerve healing and regeneration. It is one of the most promising biomaterials at present. (4) The effects of various biomaterials loaded with stem cells, growth factors or sculpted micropatterns on the repair of facial nerve injury were summarized. “Multiple combination” is the trend of nerve conduit development. The combination of cells and growth factors can effectively promote nerve regeneration, but the difference of adsorption rate and release rate between biomaterials is large, which easily leads to resource waste and short action time. (5) The longitudinal microchannels carved on the nerve conduit can provide guidance for neuronal regeneration and speed up axon regeneration, which is the focus of future research on nerve conduit direction for facial nerve injury. 
    Figures and Tables | References | Related Articles | Metrics
    Current status and prospects of bioprosthetic heart valves
    Chen Shisong, Liu Xiaohong, Xu Zhiyun
    2023, 27 (7):  1096-1102.  doi: 10.12307/2023.105
    Abstract ( 812 )   PDF (894KB) ( 365 )   Save
    BACKGROUND: Heart valve disease is common among cardiac surgical disorders, and prosthetic heart valve replacement surgery is the standard treatment for symptomatic valve disease. Bioprosthetic valves, an essential component of prosthetic heart valves, have made some breakthroughs in materials and therapies, but still have some drawbacks. 
    OBJECTIVE: To summarize some existing related researches on bioprosthetic valves and prospect the future.
    METHODS: The first author searched the relevant literature from January 2012 to March 2022 by computer on CNKI and PubMed databases in March 2022, using “bioprosthetic valves, biomaterials, decellularization, cross-linking agents, endothelialization, TAVR” as the Chinese and English search terms. Finally, 79 articles were included for review.
    RESULTS AND CONCLUSION: (1) Bioprosthetic valves have superior biocompatibility and hemodynamic properties, less thrombosis, and no lifelong anticoagulation for patients, but bioprosthetic valves are prone to calcification, leading to structural valve degradation and making them less durable. (2) Bovine and porcine are the primary biomaterials for traditional xenogeneic valves, and new materials are now mainly derived from transgenic pigs and fish bladders. (3) Decellularization techniques can reduce the immunogenicity of biologic valves, while decellularization combination methods can improve decellularization efficiency while protecting the extracellular matrix. (4) Chemical cross-linking agents are cytotoxic leading to calcification. Alternative fixatives or modified cross-linking methods can reduce adverse reactions; natural cross-linking agents are human-compatible and alleviate calcification. (5) Biological valve endothelialization has anticoagulant and anti-inflammatory effects, and a variety of coating techniques can facilitate the progression of endothelialization. (6) A variety of new interventional valves are being developed or put into the clinic and developing rapidly.
    Figures and Tables | References | Related Articles | Metrics
    Early thrombosis and prevention of small-diameter blood vessel prosthesis
    Shi Yehong, Wang Cheng, Chen Shijiu
    2023, 27 (7):  1110-1116.  doi: 10.12307/2023.020
    Abstract ( 511 )   PDF (1641KB) ( 63 )   Save
    BACKGROUND: Small-diameter blood vessel prosthesis has a wide application value in the treatment of peripheral vascular diseases, but the problem of graft failure due to early thrombosis needs to be solved.
    OBJECTIVE: To summarize research progress on early thrombosis and prevention of small-diameter blood vessel prosthesis. 
    METHODS: The relevant literature published on CNKI, Wanfang, PubMed, and Google Scholar databases from 2000 to 2020 was retrieved by the first author. The Chinese search terms were “small-diameter blood vessel prosthesis, small-diameter tubular stents, tissue-engineered blood vessels, antithrombotic, thrombosis, hemocompatibility, hydrophilicity, endothelialization”. The English search terms were “small-caliber vascular graft, vascular tissue engineering applications, endothelialization, hemocompatibility, surface modification”. The relevant literature on the pathophysiological mechanism and prevention of small-diameter blood vessel prosthesis thrombosis in China and abroad was retrieved, and the surface modification and endothelialization of biological materials were taken as the inclusion criteria. Finally, 57 articles were selected for review.
    RESULTS AND CONCLUSION: Prevention of thrombosis is a hotspot and a difficulty in the study of small-diameter blood vessel prosthesis. The research progress at home and abroad in recent years shows that the early thrombosis of small-diameter blood vessel prosthesis is related to plasma protein adsorption and contact activation of coagulation factors. By improving the surface hydrophilicity, releasing antithrombotic substances, planting seed cells and target gene induction, the thrombosis of small-diameter blood vessel prosthesis has been improved to a certain extent, but it is still in the experimental stage, and there is still a certain distance from clinical application. Therefore, it is necessary to further explore or optimize a more suitable vascular material to provide more choices for clinical application.
    Figures and Tables | References | Related Articles | Metrics
    Application and design of piezoelectric materials for bone defect repair
    Tang Haotian, Liao Rongdong, Tian Jing
    2023, 27 (7):  1117-1125.  doi: 10.12307/2023.044
    Abstract ( 806 )   PDF (1330KB) ( 249 )   Save
    BACKGROUND: Bone has the piezoelectric effect, which can transform its stress into electrical signals on the bone surface, and regulate bone metabolism and growth through electrical signals. As bone implants, the bioelectrical piezoelectric materials can promote bone healing by generating surface charges and restoring the potential of injured tissue. 
    OBJECTIVE: To introduce the piezoelectric effect of the bone, the feasibility of piezoelectric materials on promoting bone repair and research progress of piezoelectric materials applied to bone tissue engineering from the perspective of piezoelectricity and review the osteogenesis mechanism of piezoelectric materials in order to provide new ideas for bone defect repair. 
    METHODS: Using “piezoelectric effect, piezoelectric materials, piezoelectric ceramic, piezoelectric polymers, osteogenesis, bone tissue engineering, scaffolds, bone defect, energy harvester” as Chinese and English search terms, 88 articles were searched and summarized on PubMed, Web of Science, ScienceDirect, CNKI and Wanfang databases. 
    RESULTS AND CONCLUSION: (1) Piezoelectric materials can simulate the bioelectric microenvironment of extracellular matrix of bone tissue due to the piezoelectric properties of generating electricity when deformed and can be made into scaffolds to enhance bone repair function without relying on growth factors or drugs by applying electrical stimulation to bone tissue. (2) Piezoelectric materials promote osteogenesis by stimulating voltage-gated calcium channel and α5β1 integrin, increasing regional blood flow and other approaches. (3) At present, no single piezoelectric material can meet the characteristics of piezoelectric materials applied to bone tissue engineering. Therefore, piezoelectric composites made from combining piezoelectric ceramics with piezoelectric polymers or bioactive materials are consequently created. Comparing with piezoelectric ceramics, piezoelectric composites are easier to process, demonstrating superior biocompatibility and enhanced functions of promoting bone cell adhesion and mineralization, which makes it the best piezoelectric material for the treatment of bone defects. (4) Although piezoelectric materials can simulate the bioelectric microenvironment of bone tissue to enhance osteogenesis, the mechanism of piezoelectric materials interacting with bone cells is not clear, and the microenvironment of different bone tissues is unique, which limits the clinical application of piezoelectric materials. With the further study of biomaterials and elucidation of the interaction between piezoelectric materials and cells, piezoelectric materials are expected to provide new ways for the repair of bone defects.   
    Figures and Tables | References | Related Articles | Metrics
    Piezoelectric materials for vascularized bone regeneration
    Xu Yan, Li Ping, Lai Chunhua, Zhu Peijun, Yang Shuo, Xu Shulan
    2023, 27 (7):  1126-1132.  doi: 10.12307/2023.031
    Abstract ( 609 )   PDF (1074KB) ( 166 )   Save
    BACKGROUND: Due to the inherent piezoelectric properties of bone and vascular tissues, piezoelectric materials have been developed and investigated in the field of vascularized bone tissue regeneration. Therefore, the effects of piezoelectric materials on cellular response and tissue regeneration in the electrical microenvironment of bone and vascular tissues were systematically investigated so as to overcome the limitations of insufficient neovascularization in tissue-engineered bone grafts, widening piezoelectric materials for their clinical applications.
    OBJECTIVE: To review the application and progress of piezoelectric biomaterials in the field of vascularized bone regeneration.
    METHODS: The key words included “piezoelectric material, bone regeneration, vascularization, angiogenesis” in Chinese and English. The articles published from 2011 to 2021 were searched on PubMed, Web of Science and CNKI.
    RESULTS AND CONCLUSION: Piezoelectric biomaterials possessed excellent biocompatibility and superior piezoelectricity. The electrical signals generated from the piezoelectric effect not only stimulate bone and vascular tissues but also mediate tissue regeneration. Piezoelectric biomaterials can overcome the drawbacks of inert biomaterials without the bioactivity, exhibiting the promising prospects for application in vascularized bone regeneration. Nevertheless, the mechanisms for piezoelectric materials regulating tissue repair and regeneration remain unknown. There are few comprehensive studies targeting the overall regeneration of vascularized bone. The shortcomings of the performance of piezoelectric materials, such as non-degradation properties and insufficient mechanical properties, should be further improved. 
    Figures and Tables | References | Related Articles | Metrics
    Mesenchymal stem cell therapy for pneumoconiosis using nanomaterials combined with multi-modal molecular imaging
    Xue Ting, Zhang Xinri, Kong Xiaomei
    2023, 27 (7):  1133-1140.  doi: 10.12307/2023.083
    Abstract ( 536 )   PDF (1425KB) ( 104 )   Save
    BACKGROUND: Previous studies indicate that mesenchymal stem cells are used for therapy of pneumoconiosis. However, related studies are still at the stage of preclinical research due to a lack of effective tracing techniques in vivo for mesenchymal stem cells. Therefore, these effective tracing techniques in vivo for stem cells are the key to solve it. 
    OBJECTIVE: To review the research progresses of present therapy situations for pneumoconiosis, related studies on mesenchymal stem cell therapy for pneumoconiosis and different nanoparticles combined with multi-modal molecular imaging in mesenchymal stem cell therapy for pneumoconiosis, evaluate the contribution, effect and prospect of different types of nanomaterials multi-modal imaging tracking technology in the research status of mesenchymal stem cell therapy for pneumoconiosis, and analyze the present problems and future development directions. 
    METHODS: PubMed database was searched for articles published from 2016 to 2021. Key words were “pneumoconiosis, pulmonary fibrosis, stem cells, MSCs, trace, nanoparticles, multi-modal imaging, therapy”. According to the inclusion and exclusion criteria, 60 relevant articles were finally included for review. 
    RESULTS AND CONCLUSION: (1) Preclinical studies indicate that gold nanoparticles, magnetic nanoparticles and near-infrared-long persistent luminescence nanoparticles are innovative and ingenious in design with a series of advantages such as biocompatibility, stability, safety and capabilities of multi-modal imaging. Initial effectiveness is achieved in preclinical applications of in vivo tracking and anti-fibrosis therapeutic evaluation in the process of anti-pulmonary fibrosis treatment of mesenchymal stem cells. Meanwhile, each nanoparticle has its own advantages, for instance, long-term in vivo tracking, targeting special localization and long persistent luminescence respectively are merits of the gold nanoparticles, magnetic nanoparticles and near-infrared-long persistent luminescence nanoparticles. (2) Gold nanoparticles are the most promising nanoparticles of clinical application in the studies on the mesenchymal stem cell therapy for pneumoconiosis using nanoparticles combined with multi-modal molecular imaging, to a large extent, which promote the progress and clinical transformation in the area of mesenchymal stem cell therapy for pneumoconiosis. (3) Reliable technology of research on nanoparticles combined with multi-modal molecular imaging is provided to clinical application for realizing the mesenchymal stem cell therapy for pneumoconiosis. It is of great significance for propelling the clinical transformation and application of technology of targeting therapy for pneumoconiosis. (4) In the era of precision medicine, further study and detailed exploration are needed in the future to elucidate the mechanism of mesenchymal stem cell therapy for pneumoconiosis, to solve the critical problems including enhancing the targeted accumulation of nanoparticles-labeled mesenchymal stem cells, increasing the cellular uptake, controlling sustained release efficacy, prolonging the half-life of drugs and maintaining stable blood concentration, and how to combine multi-modal molecular imaging of nanoparticles with the diagnosis-and-treatment integration of drug delivery system with versatile therapeutic functions and biodegradable and cleared in vivo characteristics. 
    Figures and Tables | References | Related Articles | Metrics
    Effects of different dressings in the treatment of burn wounds: a network meta-analysis
    Li Wenjie, You Aijia, Zhou Junli, Fang Sujuan, Li Chun
    2023, 27 (7):  1141-1148.  doi: 10.12307/2023.007
    Abstract ( 682 )   PDF (1370KB) ( 95 )   Save
    OBJECTIVE: There are a variety of external dressings for treating burn, but which one is better than others has not been confirmed by evidence-based research. This article evaluated the efficacy of eleven dressings in treating burn wounds by network meta-analysis. 
    METHODS: Computer search was conducted on CNKI, Wanfang Data Knowledge Service Platform, VIP Database, CBM, PubMed, Embase, Web of Science, and Cochrane Library. The search time was from the database establishment to August 2021. The randomized controlled clinical trials of different dressings for treating burn wounds were included. The literature was screened and extracted, and the software RevMan 5.4 and Stata 14.2 were used to evaluate the literature quality and analyze the data. 
    RESULTS: A total of 32 clinical randomized controlled trials involving 3 795 burn patients and 11 kinds of dressings were included. The results of the network meta-analysis showed that (1) in terms of shortening burn wound healing time, which ranked as follows from good to bad: recombinant human granulocyte-macrophage colony-stimulating factor > platelet-rich plasma > aloe vera gel > fibroblast growth factor > silver ion dressing > amnion > recombinant human epidermal growth factor > honey dressing > traditional dressings > silver sulfadiazine cream > porcine xenograft dressings. (2) In terms of controlling the burn wound infection rate, which ranked as follows from good to bad: honey dressing > porcine xenograft dressings > silver ion dressing > aloe vera gel > silver sulfadiazine cream > platelet-rich plasma > traditional dressings. 
    CONCLUSION: The recombinant human granulocyte-macrophage colony-stimulating factor had the best overall effect on shortening the healing time of burn wound, and the honey dressing had the best overall effect on controlling the infection rate of burn wound. However, more high-quality randomized controlled trials are needed to further confirm this point in the future.
    Figures and Tables | References | Related Articles | Metrics